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1.  Fenestrated Endovascular Grafts for the Repair of Juxtarenal Aortic Aneurysms 
Executive Summary
Endovascular repair of abdominal aortic aneurysm (AAA) allows the exclusion of the dilated aneurismal segment of the aorta from the systematic circulation. The procedure requires, however, that the endograft extends to the healthy parts of the aorta above and below the aneurysm, yet the neck of a juxtarenal aortic aneurysm (JRA) is too short for a standard endovascular repair. Fenestrated endovascular aortic repair (f—EVAR) provides a solution to overcome this problem by enabling the continuation of blood flow to the renal and visceral arteries through holes or ‘fenestrations’ in the graft. These fenestrations are designed to match the ostial diameter of the renal and visceral arteries.
There are three varieties fenestration, small, large, and scallop, and their location needs to be customized to fit the anatomy of the patient. If the device is not properly designed, if the alignment is inaccurate, or if the catheterization of the visceral arteries is not possible, the procedure may fail. In such cases, conversion to open surgery may become the only option as fenestrated endografts are not retrievable.
It is recommended that a stent be placed within each small fenestration to the target artery to prevent shuttering of the artery or occlusion. Many authors have noted an increased risk of vessel occlusion in unstented fenestrations and scallops.
Once placed in a patient, life-long follow-up at regular intervals is necessary to ensure the graft remains in its intended location, and that the components have adequate overlap. Should the need arise, routine follow-up allows the performance of timely and appropriate intervention through detection of events that could impact the long-term outcomes.
Alternative Technology
The technique of fenestrated endovascular grafting is still in evolution and few studies have been with published mid-term outcome data. As the technique become more common in vascular surgery practices, it will be important to determine if it can provide better outcomes than open surgical repair (OSR).
In an OSR approach, aortic clamping above one or both renal arteries, or above the visceral arteries, is required. The higher the level of aortic clamping, the greater the risk of cardiac stress and renal or visceral ischemia. During suprarenal or supraceliac aortic clamping, strain-induced myocardial ischemia may also occur due to concomitant rise in cardiac afterload and a decrease in cardiac output. Reports indicate that 6% of patients undergoing surgical repair develop myocardial infarction. The ideal level of clamp location remains controversial with conflicting views having been reported.
A search of electronic databases (OVID MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, The Cochrane Library, and the International Agency for Health Technology Assessment [INAHTA] database was undertaken to identify evidence published from January 1, 2004 to December 19, 2008. The search was limited to English-language articles and human studies. The automatic search alerts were received and reviewed up to March 23, 2009.
The literature search and automatic search update identified 320 citations, of which 13 met inclusion/exclusion criteria. One comparative study presented at an international seminar, five single-arm studies on f—EVAR, and 7 studies on OSR (one prospective and six retrospective) were considered for this analysis.
To grade the strength of the body of evidence, the grading system formulated by the GRADE working group and adopted by MAS, was applied. The GRADE system classifies evidence quality as high (Grade A), moderate (Grade B), or low (Grade C) according to four key elements: study design, study quality, consistency across studies, and directness.
A summary of the characteristics of the f—EVAR and OSR studies found through the literature search is shown in Table ES-1.
Patient Characteristics: f–EVAR Studies versus OSR Studies
JRA, Juxtarenal aortic aneurysm; SRA, Suprarenal aortic aneurysm; TAA, Thoracic aortic aneurysm
Mortality Outcomes
The pooled estimate for 30-day mortality was 1.8% among the f—EVAR studies and 3.1% among the OSR studies that reported data for the repair of JRA separately. The pooled estimate for late mortality was 12.8% among the f—EVAR studies and 23.7% among the OSR studies that reported data for JRA separately.
Visceral Artery Events Reported in f—EVAR Studies
Renal Events during f-EVAR
A total of three main renal arteries and two accessory renal arteries became occluded during the procedure. These were all due to technical issues, except one accessory renal artery in which the artery was intentionally covered. One patient required open surgery following the procedure.
Renal Events During the follow-up
A total of 12 renal arteries (12 patients) were found to be occluded during follow-up. In two patients, the same side accessory renal artery was also occluded. Four (1.5%) patients lost one kidney and five (2.3%) patients underwent dialysis, three (1.4%) of which became permanent.
A total of 16 cases of renal artery stenosis (16 patients) occurred during follow-up. Eight of these were treated and eight were observed. Segmental renal infarcts were found in six patients but renal function was not impaired.
Mesenteric Events during f-EVAR
Three mesenteric events occurred during the f—EVAR procedures resulting in two deaths. One patient developed bowel ischemia due to embolization of the superior mesenteric artery (SMA); this patient died 13 days after the procedure from multiorgan failure. One patient died eights days after the procedure from mesenteric ischemia and bowel perforation. The third SMA event occurred during surgery with subsequent occlusion in early follow-up.
Mesenteric Events during Follow-up
During follow-up, five (1.8%) SMA occlusions/partial occlusions and one SMA stenosis were noted. Three of the five patients with SMA occlusion/partial occlusion remained asymptomatic and no further intervention was necessary. One patient underwent SMA bypass surgery and in two patients, the problem solved by SMA stenting. A summary of the outcomes reported in the f—EVAR and OSR studies is shown in Table ES-2.
Summary of Outcomes: Fenestrated Endovascular Graft Versus Open Surgical Repair for Treatment of Juxtarenal Aortic Aneurysm
Short- and medium-term results (up to 2 years) of f—EVAR for the repair of JRA showed that outcomes in f—EVAR series compare favourably with the figures for the OSR series; however, uncertainty remains regarding the long-term results. The following observations are based on low quality evidence.
F—EVAR has lower 30-day mortality than OSR (1.8% vs. 3.1%) and a lower late-mortality over the period of time that patients have been followed (12.8% vs. 23.7%).
There is a potential for the loss of target vessels during or after f—EVAR procedures. Loss of a target vessel may lead to loss of its respective end organ. The risk associated with this technique is mainly due to branch vessel ischemia or occlusion (primarily among the renal arteries and SMA). Ischemia or occlusion of these arteries can occur during surgery due to technical failure and/or embolization or it may occur during follow-up due to graft complications such as graft migration, component separation, or arterial thrombosis. The risk of kidney loss in this series of f—EVAR studies was 1.5% and the risk of mesenteric ischemia was 3.3%. In the OSR studies, the risk of developing renal insufficiency was 14.4% and the risk of mesenteric ischemia was 2.9%.
F—EVAR has a lower rate of postoperative cardiac and pulmonary complications.
Endoleak occurs in 22.5% of patients undergoing f—EVAR (all types) and about 8% of these require treatment. Most of the interventions performed to treat such endoleaks conducted using a minimally invasive approach.
Due to the complexity of the technique, patients must be appropriately selected for f—EVAR, the procedure performed by highly experienced operators, and in centers with advanced, high-resolution imaging systems to minimize the risk of complications.
Graft fenestrations have to be custom designed for each patient to fit and match the anatomy of their visceral arteries. Planning and sizing thus requires scrutiny of the target vessels with a high degree precision. This is important not only to prevent end organ ischemia and infarction, but to avoid prolonging procedures and subsequent adverse outcomes.
Assuming the average cost range of FEVAR procedure is $24,395-$30,070 as per hospital data and assuming the maximum number of annual cases in Ontario is 116, the average estimated cost impact range to the province for FEVAR procedures is $2.83M-$3.49M annually.
PMCID: PMC3377528  PMID: 23074534
2.  Suprarenal or Supraceliac Aortic Clamping during Repair of Infrarenal Abdominal Aortic Aneurysms 
Texas Heart Institute Journal  2001;28(4):254-264.
Suprarenal or supraceliac aortic clamping during repair of infrarenal abdominal aortic aneurysms can be complicated by renal, hepatic, and intestinal ischemia. To determine whether suprarenal or supraceliac clamping increases morbidity and mortality, we retrospectively reviewed our recent nonrandomized experience. Between January 1993 and December 1998, 716 patients underwent elective (n=682) or urgent (n=34) infrarenal abdominal aortic aneurysm repair. Infrarenal clamping was used in 516 (72.1%) and suprarenal or supraceliac clamping in 200 (27.9%). The suprarenal/supraceliac group had significantly more older patients (≥70 years of age) (65.5% vs 47.7%) and a higher incidence of preoperative renal insufficiency (7.5% vs 5.5%). Suprarenal or supraceliac clamping was used during repair of ruptured (n=25), juxtarenal (n=7), or inflammatory abdominal aortic aneurysms (n=4); during concomitant renal or visceral revascularization (n = 43); in other difficult settings (n=13); or at the surgeon's discretion (n=108). The decision for such clamping was always made during surgery. In treating ruptured aneurysms, suprarenal/supraceliac clamping (25/200) was used more often than infrarenal clamping (9/516) (12.5% vs 1.74%). Operative times were similar in both groups, but transfusion requirements and length of hospital stay were slightly greater in the suprarenal/supraceliac group. Perioperative mortality was 3.1% overall, but higher in the suprarenal/supraceliac group than in the infrarenal (7.5% vs 1.4%). Postoperative complications developed in 26 (13%) of patients who underwent suprarenal/supraceliac clamping. Abdominal re-exploration was required in 9 other patients. We conclude that, despite associated comorbidities, elective suprarenal/supraceliac clamping during infrarenal abdominal aortic aneurysm repair is safe, facilitates repair, and does not significantly increase mortality. (Tex Heart Inst J 2001;28:254–64)
PMCID: PMC101201  PMID: 11777150
Aortic aneurysm, abdominal; supraceliac clamping; suprarenal clamping
3.  Predictive Value of Conventional Computed Tomography 
Texas Heart Institute Journal  2002;29(3):172-175.
The present study aimed to evaluate the diagnostic reliability of computed tomography in determining the proximal extent of abdominal aortic aneurysms and the possibility of infrarenal clamping.
Preoperative computed tomographic findings, together with the operative data for 95 patients, were retrospectively analyzed in light of the operative findings. Eighty-nine (93.68%) of the patients were men and 6 (6.32%) were women, with a mean age of 66.27 ± 18.14 years.
Diagnosis of infrarenal aneurysm by computed tomography was confirmed at the time of surgery in 91 (95.79%) of 95 patients. The negative-predictive value of computed tomography in detecting supra-aneurysmal renal arteries was found to be 95.79%. The specificity was 98.91%. Infrarenal cross-clamping was performed in 59 (62.11%) of 95 patients, whose aortic segments between the renal artery orifices and the proximal borders of the aneurysms had a mean length of 26.4 ± 7.11 mm by computed tomography. Suprarenal clamping was required in 36 (37.89%) of the 95 patients, whose aortic segments had a mean length of 12.7 ± 3.48 mm.
We conclude that conventional computed tomography is reasonably accurate in determining the proximal extent of abdominal aortic aneurysms. Although there is a high rate of error in determining the possibility of infrarenal clamping when no specific measurements are taken, infrarenal clamping can be planned when measurement by computed tomography shows a length of ≥26 mm between the renal arteries and the proximal extent of the aneurysm. In patients with shorter aortic segments, suprarenal aortic clamping should be considered. (Tex Heart Inst J 2002;29:172–5)
PMCID: PMC124755  PMID: 12224719
Aorta, abdominal/surgery; aortic aneurysm/diagnosis; aortic aneurysm, abdominal/radiography; aortic aneurysm, abdominal/surgery; predictive value of tests; retrospective study; tomography, X-ray computed
4.  Endovascular Repair of Descending Thoracic Aortic Aneurysm 
Executive Summary
To conduct an assessment on endovascular repair of descending thoracic aortic aneurysm (TAA).
Clinical Need
Aneurysm is the most common condition of the thoracic aorta requiring surgery. Aortic aneurysm is defined as a localized dilatation of the aorta. Most aneurysms of the thoracic aorta are asymptomatic and incidentally discovered. However, TAA tends to enlarge progressively and compress surrounding structures causing symptoms such as chest or back pain, dysphagia (difficulty swallowing), dyspnea (shortness of breath), cough, stridor (a harsh, high-pitched breath sound), and hoarseness. Significant aortic regurgitation causes symptoms of congestive heart failure. Embolization of the thrombus to the distal arterial circulation may occur and cause related symptoms. The aneurysm may eventually rupture and create a life-threatening condition.
The overall incidence rate of TAA is about 10 per 100,000 person-years. The descending aorta is involved in about 30% to 40% of these cases.
The prognosis of large untreated TAAs is poor, with a 3-year survival rate as low as 25%. Intervention is strongly recommended for any symptomatic TAA or any TAA that exceeds twice the diameter of a normal aorta or is 6 cm or larger. Open surgical treatment of TAA involves left thoracotomy and aortic graft replacement. Surgical treatment has been found to improve survival when compared with medical therapy. However, despite dramatic advances in surgical techniques for performing such complex operations, operative mortality from centres of excellence are between 8% and 20% for elective cases, and up to 50% in patients requiring emergency operations. In addition, survivors of open surgical repair of TAAs may suffer from severe complications. Postoperative or postprocedural complications of descending TAA repair include paraplegia, myocardial infarction, stroke, respiratory failure, renal failure, and intestinal ischemia.
The Technology
Endovascular aortic aneurysm repair (EVAR) using a stent graft, a procedure called endovascular stent-graft (ESG) placement, is a new alternative to the traditional surgical approach. It is less invasive, and initial results from several studies suggest that it may reduce mortality and morbidity associated with the repair of descending TAAs.
The goal in endovascular repair is to exclude the aneurysm from the systemic circulation and prevent it from rupturing, which is life-threatening. The endovascular placement of a stent graft eliminates the systemic pressure acting on the weakened wall of the aneurysm that may lead to the rupture. However, ESG placement has some specific complications, including endovascular leak (endoleak), graft migration, stent fracture, and mechanical damage to the access artery and aortic wall.
The Talent stent graft (manufactured by Medtronic Inc., Minneapolis, MN) is licensed in Canada for the treatment of patients with TAA (Class 4; licence 36552). The design of this device has evolved since its clinical introduction. The current version has a more flexible delivery catheter than did the original system. The prosthesis is composed of nitinol stents between thin layers of polyester graft material. Each stent is secured with oversewn sutures to prevent migration.
Review Strategy
To compare the effectiveness and cost-effectiveness of ESG placement in the treatment of TAAs with a conventional surgical approach
To summarize the safety profile and effectiveness of ESG placement in the treatment of descending TAAs
Measures of Effectiveness
Primary Outcome
Mortality rates (30-day and longer term)
Secondary Outcomes
Technical success rate of introducing a stent graft and exclusion of the aneurysm sac from systemic circulation
Rate of reintervention (through surgical or endovascular approach)
Measures of Safety
Complications were categorized into 2 classes:
Those specific to the ESG procedure, including rates of aneurysm rupture, endoleak, graft migration, stent fracture, and kinking; and
Those due to the intervention, either surgical or endovascular. These include paraplegia, stroke, cardiovascular events, respiratory failure, real insufficiency, and intestinal ischemia.
Inclusion Criteria
Studies comparing the clinical outcomes of ESG treatment with surgical approaches
Studies reporting on the safety and effectiveness of the ESG procedure for the treatment of descending TAAs
Exclusion Criteria
Studies investigating the clinical effectiveness of ESG placement for other conditions such as aortic dissection, aortic ulcer, and traumatic injuries of the thoracic aorta
Studies investigating the aneurysms of the ascending and the arch of the aorta
Studies using custom-made grafts
Literature Search
The Medical Advisory Secretariat searched The International Network of Agencies for Health Technology Assessment and the Cochrane Database of Systematic Reviews for health technology assessments. It also searched MEDLINE, EMBASE, Medline In-Process & Other Non-Indexed Citations, and Cochrane CENTRAL from January 1, 2000 to July 11, 2005 for studies on ESG procedures. The search was limited to English-language articles and human studies.
One health technology assessment from the United Kingdom was identified. This systematic review included all pathologies of the thoracic aorta; therefore, it did not match the inclusion criteria. The search yielded 435 citations; of these, 9 studies met inclusion criteria.
Summary of Findings
The results of a comparative study found that in-hospital mortality was not significantly different between ESG placement and surgery patients (2 [4.8%] for ESG vs. 6 [11.3%] for surgery).
Pooled data from case series with a mean follow-up ranging from 12 to 38 months showed a 30-day mortality and late mortality rate of 3.9% and 5.5%, respectively. These rates are lower than are those reported in the literature for surgical repair of TAA.
Case series showed that the most common cause of early death in patients undergoing endovascular repair is aortic rupture, and the most common causes of late death are cardiac events and aortoesophageal or aortobronchial fistula.
Technical Success Rate
Technical success rates reported by case series are 55% to 100% (100% and 94.4% in 2 studies with all elective cases, 89% in a study with 5% emergent cases, and 55% in a study with 42% emergent cases).
Surgical Reintervention
In the comparative study, 3 (7.1%) patients in the ESG group and 14 (26.5%) patients in the surgery group required surgical reintervention. In the ESG group, the reasons for surgical intervention were postoperative bleeding at the access site, paraplegia, and type 1 endoleak. In the surgical group, the reasons for surgery were duodenal perforation, persistent thoracic duct leakage, false aneurysm, and 11 cases of postoperative bleeding.
Pooled data from case series show that 9 (2.6%) patients required surgical intervention. The reasons for surgical intervention were endoleak (3 cases), aneurysm enlargement and suspected infection (1 case), aortic dissection (1 case), pseudoaneurysm of common femoral artery (1 case), evacuation of hematoma (1 case), graft migration (1 case), and injury to the access site (1 case).
Endovascular Revision
In the comparative study, 3 (7.1%) patients required endovascular revision due to persistent endoleak.
Pooled data from case series show that 19 (5.3%) patients required endovascular revision due to persistent endoleak.
Graft Migration
Two case series reported graft migration. In one study, 3 proximal and 4 component migrations were noted at 2-year follow-up (total of 5%). Another study reported 1 (3.7%) case of graft migration. Overall, the incidence of graft migration was 2.6%.
Aortic Rupture
In the comparative study, aortic rupture due to bare stent occurred in 1 case (2%). The pooled incidence of aortic rupture or dissection reported by case series was 1.4%.
Postprocedural Complications
In the comparative study, there were no statistically significant differences between the ESG and surgery groups in postprocedural complications, except for pneumonia. The rate of pneumonia was 9% for those who received an ESG and 28% for those who had surgery (P = .02). There were no cases of paraplegia in either group. The rate of other complications for ESG and surgery including stroke, cardiac, respiratory, and intestinal ischemia were all 5.1% for ESG placement and 10% for surgery. The rate for mild renal failure was 16% in the ESG group and 30% in the surgery group. The rate for severe renal failure was 11% for ESG placement and 10% for surgery.
Pooled data from case series show the following postprocedural complication rates in the ESG placement group: paraplegia (2.2%), stroke (3.9%), cardiac (2.9%), respiratory (8.7%), renal failure (2.8%), and intestinal ischemia (1%).
Time-Related Outcomes
The results of the comparative study show statistically significant differences between the ESG and surgery group for mean operative time (ESG, 2.7 hours; surgery, 5 hours), mean duration of intensive care unit stay (ESG, 11 days; surgery, 14 days), and mean length of hospital stay (ESG, 10 days; surgery, 30 days).
The mean duration of intensive care unit stay and hospital stay derived from case series is 1.6 and 7.8 days, respectively.
Ontario-Based Economic Analysis
In Ontario, the annual treatment figures for fiscal year 2004 include 17 cases of descending TAA repair procedures (source: Provincial Health Planning Database). Fourteen of these have been identified as “not ruptured” with a mean hospital length of stay of 9.23 days, and 3 cases have been identified as “ruptured,” with a mean hospital length of stay of 28 days. However, because one Canadian Classification of Health Interventions code was used for both procedures, it is not possible to determine how many were repaired with an EVAR procedure or with an open surgical procedure.
Hospitalization Costs
The current fiscal year forecast of in-hospital direct treatment costs for all in-province procedures of repair of descending TAAs is about $560,000 (Cdn). The forecast in-hospital total cost per year for in-province procedures is about $720,000 (Cdn). These costs include the device cost when the procedure is EVAR (source: Ontario Case Costing Initiative).
Professional (Ontario Health Insurance Plan) Costs
Professional costs per treated patient were calculated and include 2 preoperative thoracic surgery or EVAR consultations.
The professional costs of an EVAR include the fees paid to the surgeons, anesthetist, and surgical assistant (source: fee service codes). The procedure was calculated to take about 150 minutes.
The professional costs of an open surgical repair include the fees of the surgeon, anesthetist, and surgical assistant. Open surgical repair was estimated to take about 300 minutes.
Services provided by professionals in intensive care units were also taken into consideration, as were the costs of 2 postoperative consultations that the patients receive on average once they are discharged from the hospital. Therefore, total Ontario Health Insurance Plan costs per treated patient treated with EVAR are on average $2,956 (ruptured or not ruptured), as opposed to $5,824 for open surgical repair and $6,157 for open surgical repair when the aneurysm is ruptured.
Endovascular stent graft placement is a less invasive procedure for repair of TAA than is open surgical repair.
There is no high-quality evidence with long-term follow-up data to support the use of EVAR as the first choice of treatment for patients with TAA that are suitable candidates for surgical intervention.
However, short- and medium-term outcomes of ESG placement reported by several studies are satisfactory and comparable to surgical intervention; therefore, for patients at high risk of surgery, it is a practical option to consider. Short- and medium-term results show that the benefit of ESG placement over the surgical approach is a lower 30-day mortality and paraplegia rate; and shorter operative time, ICU stay, and hospital stay.
PMCID: PMC3382300  PMID: 23074469
5.  Endovascular Repair of Abdominal Aortic Aneurysm 
The Medical Advisory Secretariat conducted a systematic review of the evidence on the effectiveness and cost-effectiveness of endovascular repair of abdominal aortic aneurysm in comparison to open surgical repair. An abdominal aortic aneurysm [AAA] is the enlargement and weakening of the aorta (major blood artery) that may rupture and result in stroke and death. Endovascular abdominal aortic aneurysm repair [EVAR] is a procedure for repairing abdominal aortic aneurysms from within the blood vessel without open surgery. In this procedure, an aneurysm is excluded from blood circulation by an endograft (a device) delivered to the site of the aneurysm via a catheter inserted into an artery in the groin. The Medical Advisory Secretariat conducted a review of the evidence on the effectiveness and cost-effectiveness of this technology. The review included 44 eligible articles out of 489 citations identified through a systematic literature search. Most of the research evidence is based on non-randomized comparative studies and case series. In the short-term, EVAR appears to be safe and comparable to open surgical repair in terms of survival. It is associated with less severe hemodynamic changes, less blood transfusion and shorter stay in the intensive care and hospital. However, there is concern about a high incidence of endoleak, requiring secondary interventions, and in some cases, conversion to open surgical repair. Current evidence does not support the use of EVAR in all patients. EVAR might benefit individuals who are not fit for surgical repair of abdominal aortic aneurysm and whose risk of rupture of the aneurysm outweighs the risk of death from EVAR. The long-term effectiveness and cost-effectiveness of EVAR cannot be determined at this time. Further evaluation of this technology is required.
The objective of this health technology policy assessment was to determine the effectiveness and cost-effectiveness of endovascular repair of abdominal aortic aneurysms (EVAR) in comparison to open surgical repair (OSR).
Clinical Need
An abdominal aortic aneurysm (AAA) is a localized, abnormal dilatation of the aorta greater than 3 cm or 50% of the aortic diameter at the diaphragm. (1) A true AAA involves all 3 layers of the vessel wall. If left untreated, the continuing extension and thinning of the vessel wall may eventually result in rupture of the AAA. The risk of death from ruptured AAA is 80% to 90%. (61) Heller et al. (44) analyzed information from a national hospital database in the United States. They found no significant change in the incidence rate of elective AAA repair or ruptured AAA presented to the nation’s hospitals. The investigators concluded that technologic and treatment advances over the past 19 years have not affected the outcomes of patients with AAAs, and the ability to identify and to treat patients with AAAs has not improved.
Classification of Abdominal Aortic Aneurysms
At least 90% of the AAAs are affected by atherosclerosis, and most of these aneurysms are below the level of the renal arteries.(1)
An abdominal aortic aneurysm may be symptomatic or asymptomatic. An AAA may be classified according to their sizes:(7)
Small aneurysms: less than 5 cm in diameter.
Medium aneurysms: 5-7cm.
Large aneurysms: more than 7 cm in diameter.
Small aneurysms account for approximately 50% of all clinically recognized aneurysms.(7)
Aortic aneurysms may be classified according to their gross appearance as follows (1):
Fusiform aneurysms affect the entire circumference of a vessel, resulting in a diffusely dilated lesion
Saccular aneurysms involve only a portion of the circumference, resulting in an outpouching (protrusion) in the vessel wall.
Prevalence of Abdominal Aortic Aneurysms
In community surveys, the prevalence of AAA is reported to be between 1% and 5.4%. (61) The prevalence is related to age and vascular risk factors. It is more common in men and in those with a positive family history.
In Canada, Abdominal aortic aneurysms are the 10th leading cause of death in men 65 years of age or older. (60) Naylor (60) reported that the rate of AAA repair in Ontario has increased from 38 per 100,000 population in 1981/1982 to 54 per 100,000 population in 1991/1992. For the period of 1989/90 to 1991/92, the rate of AAA repair in Ontarians age 45 years and over was 53 per 100,000. (60) In the United States, about 200,000 new cases are diagnosed each year, and 50,000 to 60,000 surgical AAA repairs are performed. (2) Ruptured AAAs are responsible for about 15,000 deaths in the United States annually. One in 10 men older than 80 years has some aneurysmal change in his aorta. (2)
Symptoms of Abdominal Aortic Aneurysms
AAAs usually do not produce symptoms. However, as they expand, they may become painful. Compression or erosion of adjacent tissue by aneurysms also may cause symptoms. The formation of mural thrombi, a type of blood clots, within the aneurysm may predispose people to peripheral embolization, where blood vessels become blocked. Occasionally, an aneurysm may leak into the vessel wall and the periadventitial area, causing pain and local tenderness. More often, acute rupture occurs without any prior warning, causing acute pain and hypotension. This complication is always life-threatening and requires an emergency operation.
Diagnosis of Abdominal Aortic Aneurysms
An AAA is usually detected on routine examination as a palpable, pulsatile, and non-tender mass. (1)
Abdominal radiography may show the calcified outline of the aneurysms; however, about 25% of aneurysms are not calcified and cannot be visualized by plain x-ray. (1) An abdominal ultrasound provides more accurate detection, can delineate the traverse and longitudinal dimensions of the aneurysm, and is useful for serial documentation of aneurysm size. Computed tomography and magnetic resonance have also been used for follow-up of aortic aneurysms. These technologies, particularly contrast-enhanced computer tomography, provide higher resolution than ultrasound.
Abdominal aortography remains the gold standard to evaluate patients with aneurysms for surgery. This technique helps document the extent of the aneurysms, especially their upper and lower limits. It also helps show the extent of associated athereosclerotic vascular disease. However, the procedure carries a small risk of complications, such as bleeding, allergic reactions, and atheroembolism. (1)
Prognosis of Abdominal Aortic Aneurysms
The risk of rupture of an untreated AAA is a continuous function of aneurysm size as represented by the maximal diameter of the AAA. The annual rupture rate is near zero for aneurysms less than 4 cm in diameter. The risk is about 1% per year for aneurysms 4 to 4.9 cm, 11% per year for aneurysms 5 to 5.9 cm, and 25% per year or more for aneurysms greater than 6 cm. (7)
The 1-year mortality rate of patients with AAAs who do not undergo surgical treatment is about 25% if the aneurysms are 4 to 6 cm in diameter. This increases to 50% for aneurysms exceeding 6 cm. Other major causes of mortality for people with AAAs include coronary heart disease and stroke.
Treatment of Abdominal Aortic Aneurysms
Treatment of an aneurysm is indicated under any one of the following conditions:
The AAA is greater than 6 cm in diameter.
The patient is symptomatic.
The AAA is rapidly expanding irrespective of the absolute diameter.
Open surgical repair of AAA is still the gold standard. It is a major operation involving the excision of dilated area and placement of a sutured woven graft. The surgery may be performed under emergent situation following the rupture of an AAA, or it may be performed electively.
Elective OSR is generally considered appropriate for healthy patients with aneurysms 5 to 6 cm in diameter. (7) Coronary artery disease is the major underlying illness contributing to morbidity and mortality in OSR. Other medical comorbidities, such as chronic renal failure, chronic lung disease, and liver cirrhosis with portal hypertension, may double or triple the usual risk of OSR.
Serial noninvasive follow-up of small aneurysms (less than 5 cm) is an alternative to immediate surgery.
Endovascular repair of AAA is the third treatment option and is the topic of this review.
PMCID: PMC3387737  PMID: 23074438
6.  Predictors of Postoperative Mortality of Ruptured Abdominal Aortic Aneurysm: A Retrospective Clinical Study 
Yonsei Medical Journal  2012;53(4):772-780.
Despite significant improvements in surgery, anesthesia, and postoperative critical care, the postoperative mortality rate of ruptured abdominal aortic aneurysm (RAAA) has remained at 40% to 50% for several decades. Therefore, we evaluated factors associated with the postoperative mortality of RAAA.
Materials and Methods
From January 1999 to December 2008, a retrospective study was performed with 34 patients who underwent open repair of RAAA. The preoperative factors included age, sex, smoking, comorbidities, serum creatinine, hemoglobin, shock, pulse rate, and time from emergency room to operation room. The intraoperative factors included blood loss, transfusion, aortic clamping site and time, aneurysmal characteristics, rupture type, graft type, hourly urine output (HUO), and operative time. The postoperative factors included inotropic support, renal replacement therapy (RRT), reoperation, bowel ischemia, multiple organ failure (MOF), and intensive care unit stay. The 2-day and the 30-day mortality rates were analyzed separately.
The 2-day and the 30-day mortality rates were 14.7% and 41.2%, respectively. On univariate analysis, shock, transfusion, HUO, inotropic support and MOF for the 2-day mortality and serum creatinine, transfusion, aortic clamping site, HUO, inotropic support, RRT and MOF for the 30-day mortality were statistically significant. On multivariate analysis, shock, inotropic support and MOF for the 2-day mortality and aortic clamping site, RRT and MOF for the 30-day mortality were statistically significant.
To decrease the postoperative mortality rate of RAAA, prevention of massive hemorrhage and acute renal failure with infrarenal aortic clamping, as well as prompt operative control of bleeding and maintenance of systemic perfusion are important.
PMCID: PMC3381467  PMID: 22665345
Abdominal aortic aneurysm; ruptured; postoperative mortality
7.  Risk Factors for Postoperative Complications after Open Infrarenal Abdominal Aortic Aneurysm Repair in Koreans 
Yonsei Medical Journal  2011;52(2):339-346.
Open infrarenal abdominal aortic aneurysm (AAA) repair is performed without event in most cases. However, some patients suffer major morbidities such as renal failure, myocardial infarction, paraplegia, acute respiratory distress syndrome, or hepatic dysfunction. Predicting what kinds of patient populations are more prone to develop such complications may keep the clinicians more attentive to the patients, possibly leading to better prognoses. In this retrospective study, we searched the incidence of and risk factors for postoperative complications and their predictive equations in 162 patients who underwent open infrarenal AAA repair.
Materials and Methods
Postoperative complications were observed within 30 days. Patient characteristics, types of aneurysm and surgery, and hemodynamic and metabolic variables during the periclamp period were analyzed in relation to postoperative complications using multiple logistic regression analysis.
Postoperative complications involved the cardiac (20%), pulmonary (14%), renal (13%), gastrointestinal (6%), hepatic (3.1%), and neurologic (2.5%) systems, and bleeding occurred in 1.2% of cases. The mortality rate was 5.6%. The risk factors were age [> 67 yrs, odds ratio (OR) 2.6], clamp duration (> 110 min, OR 4.7), volume of blood transfusion (> 1,280 mL, OR 4.4), emergency operation (OR 1.4), and vasopressor infusion during clamp (OR 1.4). The prediction model was: P(x) = exp(α)/[1 + exp(α)] α;-2.2 + 0.9 × age + 1.5 × clamp duration + 1.5 × transfusion + 0.3 × emergency + 0.4 × vasopressor infusion [insert 1 if risk factors exist, otherwise, insert 0 to each variable].
A significant number of complications occurred after infrarenal AAA repair. Therefore, creating a protocol to identify and monitor high risk patients would improve postoperative care.
PMCID: PMC3051228  PMID: 21319356
Complications; infrarenal aortic aneurysm; risk factors
8.  The coral reef aorta – a single centre experience in 70 patients 
Coral reef aorta (CRA) is described as rock-hard calcifications in the visceral part of the aorta. These heavily calcified plaques grow into the lumen and can cause significant stenoses, which may lead to malperfusion of the lower limbs, visceral ischemia or hypertension due to renal ischemia. From January 1984 to February 2007, 70 patients (24 men, 46 women, mean age 59.5 years, range 14 to 81 years) underwent treatment in the Department of Vascular Surgery and Renal Transplantation, University Hospital, Heinrich-Heine-University (Düsseldorf, Germany) for CRA. The present study is based on a review of patients’ records and the prospective follow-up in the outpatient clinic. The most frequent finding was renovascular arterial hypertension (44.3%) causing headache, vertigo and visual symptoms. Intermittent claudication due to peripheral arterial occlusive disease was found in 28 patients (40.0%). Seventeen patients (24.3%) presented with chronic visceral ischemia causing diarrhea, weight loss and abdominal pain. Sixty-nine of the 70 patients (98.6%) underwent surgery; in 57 patients, aortic reconstruction was achieved with thromboendarterectomy, performed on an isolated suprarenal segment in six cases (8.7%), an infrarenal segment in 15 cases (21.7%), and the supra- and infrarenal aorta in 43 cases (62.3%). Eight patients (11.6%) died during or soon after surgery. Postoperative complications requiring corrective surgery occurred in 11 patients (15.9%). Almost one-third of the patients (n=19, 27.5%) returned for follow-up after a mean of 52.6 months (range six to 215 months). Of the 19 patients, there was significant clinical and diagnostic improvement in 16 patients (84.2%) and three patients (15.8%) were unchanged. Impairment was not observed. Despite the existing and improving surgical techniques for the treatment of CRA, its pathophysiological basis and genesis is not yet understood.
PMCID: PMC2733021  PMID: 22477301
Aorta; Atherosclerotic occlusive disease; Calcification; Coral reef aorta
9.  Vascular relaxation of canine visceral arteries after ischemia by means of supraceliac aortic cross-clamping followed by reperfusion 
The supraceliac aortic cross-clamping can be an option to save patients with hipovolemic shock due to abdominal trauma. However, this maneuver is associated with ischemia/reperfusion (I/R) injury strongly related to oxidative stress and reduction of nitric oxide bioavailability. Moreover, several studies demonstrated impairment in relaxation after I/R, but the time course of I/R necessary to induce vascular dysfunction is still controversial. We investigated whether 60 minutes of ischemia followed by 30 minutes of reperfusion do not change the relaxation of visceral arteries nor the plasma and renal levels of malondialdehyde (MDA) and nitrite plus nitrate (NOx).
Male mongrel dogs (n = 27) were randomly allocated in one of the three groups: sham (no clamping, n = 9), ischemia (supraceliac aortic cross-clamping for 60 minutes, n = 9), and I/R (60 minutes of ischemia followed by reperfusion for 30 minutes, n = 9). Relaxation of visceral arteries (celiac trunk, renal and superior mesenteric arteries) was studied in organ chambers. MDA and NOx concentrations were determined using a commercially available kit and an ozone-based chemiluminescence assay, respectively.
Both acetylcholine and calcium ionophore caused relaxation in endothelium-intact rings and no statistical differences were observed among the three groups. Sodium nitroprusside promoted relaxation in endothelium-denuded rings, and there were no inter-group statistical differences. Both plasma and renal concentrations of MDA and NOx showed no significant difference among the groups.
Supraceliac aortic cross-clamping for 60 minutes alone and followed by 30 minutes of reperfusion did not impair relaxation of canine visceral arteries nor evoke biochemical alterations in plasma or renal tissue.
PMCID: PMC2913934  PMID: 20642850
10.  A systematic review and meta-analysis of hybrid aortic arch replacement 
Annals of Cardiothoracic Surgery  2013;2(3):247-260.
Evolution in the endovascular era has influenced the management of aortic arch pathologies. Several studies have described the use of a combined endovascular and open surgical approach to the treatment of arch diseases. Hybrid repair of arch pathologies has been considered as a less invasive method, and is therefore an appealing option for high-risk patients who are unsuitable for open repairs. The aim of the present meta-analysis was to assess the efficacy of hybrid techniques in patients with aortic arch pathologies.
Extensive electronic literature search was undertaken to identify all articles published up to December 2012 that described hybrid aortic arch repair with intrathoracic supra-aortic branch revascularisation and subsequent stent graft deployment. Eligible studies were divided into two groups: group I included studies on the aortic arch debranching procedure and group II included studies that reported an elephant trunk technique (either “frozen” or stented). Separate meta-analyses were conducted in order to assess technical success, stroke, spinal cord ischemia (SCI), renal failure requiring dialysis, and cardiac and pulmonary complications rate, as well as 30-day/in-hospital mortality.
Forty-six studies were eligible for the present meta-analysis: 26 studies with a total of 956 patients reported aortic arch debranching procedures, and 20 studies with 1,316 patients performed either ‘frozen’ or stented elephant trunk technique. The pooled estimate for 30-day/in-hospital mortality was 11.9% for the arch debranching group and 9.5% for the elephant trunk group. Cerebrovascular events of any severity were found to have occurred postoperatively at a pooled rate of 7.6% and 6.2%, while irreversible spinal cord injury symptoms were present in a pooled estimate of 3.6% and 5.0% in the arch debranching and elephant trunk group, respectively. Renal failure requiring dialysis occurred at 5.7% and 3.8% in both groups, while cardiac complications rate was 6.0% in the arch debranching cohort and pulmonary complication was 19.7% in the elephant trunk cohort.
Hybrid arch techniques provide a safe alternative to open repair with acceptable short- and mid-term results. However, stroke and mortality rates remain noteworthy. Future prospective trials that compare open conventional techniques with the hybrid method or the entirely endovascular methods are needed.
PMCID: PMC3741846  PMID: 23977592
Aortic arch; hybrid; debranching; frozen elephant trunk; stented elephant trunk
11.  Determinants of Gastrointestinal Complications in Cardiac Surgery 
Texas Heart Institute Journal  2003;30(4):280-285.
We designed this study to define determinants of gastrointestinal complications after cardiac surgery. From January 1992 through December 2000, 11,058 patients underwent cardiac surgery on cardiopulmonary bypass at our institution. Data were prospectively collected and univariate and multivariate analyses conducted.
A total of 147 gastrointestinal complications occurred in 129 patients (129/11,058; 1.2%) including gastroesophagitis (18, 12.2%), upper gastrointestinal hemorrhage (42, 28.6%), perforated peptic ulcer (7, 4.7%), cholecystitis (10, 6.8%), pancreatitis (13, 8.8%), intestinal ischemia (17, 11.5%), colitis (18, 12.2%), diverticulitis (5, 3.4%), intestinal occlusion (2, 1.1%), lower gastrointestinal hemorrhage (1, 0.7%), and mixed gastrointestinal complications (14, 9.5%). Patients with gastrointestinal complications were significantly older and had significantly higher comorbidity (unstable angina, chronic renal failure, and peripheral vascular disease), morbidity (prolonged mechanical ventilation, intra-aortic balloon pumping, bleeding, acute renal failure, stroke, and infection), and mortality rates (22.5% vs 4%, P <0.0001). They also had longer cardiopulmonary bypass times and higher valvular surgery rates. Multivariate analysis identified 6 independent predictors for gastrointestinal complications: prolonged mechanical ventilation (odds ratio [OR], 5.5), postoperative renal failure (OR, 4.2), sepsis (OR, 3.6), valve surgery (OR, 3.2), preoperative chronic renal failure (OR, 2.7), and sternal infection (OR, 2.4).
Factors such as mechanical ventilation, renal failure, and sepsis are the stronger predictors for GI complications, causing splanchnic hypoperfusion, hypomotility, and hypoxia. Furthermore, excessive anticoagulation after valve replacement may lead to GI hemorrhage. Valve surgery, often requiring anticoagulation, increases bleeding. Monitoring mechanical ventilation and hemodynamic parameters, adopting early extubation and mobilization measures, preventing infections, and strictly monitoring renal function and anticoagulation may prevent catastrophic abdominal complications. (Tex Heart Inst J 2003;30:280–5)
PMCID: PMC307712  PMID: 14677737
Cardiac surgical procedures; cardiopulmonary bypass; gastrointestinal complications; independent determinants; multivariate analysis; postoperative complications/etiology; risk factors
12.  Treatment of Acute Visceral Aortic Pathology with Fenestrated-Branched Endovascular Repair in High Surgical Risk Patients 
Journal of vascular surgery  2013;58(1):56-65.e1.
The safety and feasibility of fenestrated/branched endovascular repair of acute visceral aortic disease in high risk patients is unknown. The purpose of this report is to describe our experience with surgeon-modified endografts(sm-EVAR) for the urgent or emergent treatment of pathology involving the branched segment of the aorta in patients deemed to have prohibitively high medical and/or anatomic risk for open repair.
A retrospective review was performed on all patients treated with sm-EVAR for acute indications. Planning was based on 3D-CTA reconstructions and graft configurations included various combinations of branch, fenestration, or scallop modifications.
Sixteen patients [mean age(±SD)68±10 years; 88% male] deemed high risk for open repair underwent urgent or emergent repair using sm-EVAR. Indications included: degenerative suprarenal or thoracoabdominal aneurysm (6), presumed or known mycotic aneurysm(4), anastomotic pseudoaneurysm (3), false lumen rupture of type B dissection(2), and penetrating aortic ulceration(1). Nine (56%) had previous aortic surgery and all patients were either ASA class IV(N=9) or IV-E(N=7). A total of 40 visceral vessels (celiac=10, SMA=10, RRA=10, LRA=10) were revascularized with a combination of fenestrations (33), directional graft branches (6), and graft scallops (1). Technical success was 94% (N=15/16), with one open conversion. Median contrast use was 126mL (range 41–245) and fluoroscopy time was 70 minutes(range 18–200). Endoleaks were identified intra-operatively in 4 patients [type II(N=3); IV(N=1)] but none have required remediation. Mean LOS was 12±15 days (median 5.5; range 3–59).
Single complications occurred in 5(31%) patients: brachial sheath hematoma (1), stroke(1), ileus(1), respiratory failure(1), and renal failure(1). An additional patient experienced multiple complications including spinal cord ischemia(1) and multi-organ failure resulting in death(N=1;in-hospital mortality 6.3%). The majority of patients were discharged to home (63%;N=10) or short term rehabilitation units (25%;N=4) while one patient required admission to a long-term acute care (LTAC) setting. There were no re-interventions at a median follow-up of 6.2(range 1–16.1) months. Postoperative CTA was available for all patients and demonstrated 100% branch vessel patency, with 1 type III endoleak pending intervention. There were two late deaths at 1.4 and 13.4 months due to non-aortic related pathology.
Urgent or emergent treatment of acute pathology involving the visceral aortic segment with fenestrated/branched endograft repair is feasible and safe in selected high-risk patients; however the durability of these repairs is yet to be determined.
PMCID: PMC4183351  PMID: 23706619
13.  Possible graft-related complications in visceral debranching for hybrid B dissection repair 
Annals of Cardiothoracic Surgery  2014;3(4):393-399.
Hybrid repair (HR) of thoracoabdominal aortic aneurysm (TAAA) and dissection (TAAD), consisting of rerouting renovisceral branches followed by endograft aortic repair, has been shown to be a feasible option. It is especially appealing in patients unfit for both open and total endovascular repair. In order to determine the role of dissecting etiology and intraoperative variables as risk factors for graft-related complications in visceral debranching, we retrospectively analyzed the clinical outcomes, patency rate and hemodynamic alterations of the renovisceral debranching grafts in our series.
We analyzed 55 consecutive patients who underwent thoracoabdominal aortic HR between 2001 and 2013 in our center. Forty-four procedures were performed for TAAA and 11 procedures for TAAD. In TAAD patients, dissection involved 9/44 (20.5%) renovisceral vessels. One hundred and fifty-nine visceral bypasses were made (156 retrograde; three anterograde).
Thirty-day mortality was 12.7% (n=7). Potential graft-related complications included four cases of pancreatitis (7.3%) and five of peri-operative renal failure (9.1%). At a mean follow-up of 36.1 months, the global rate of visceral graft occlusion was 9.4% (15/159), leading to fatal bowel infarction in two patients and kidney loss in seven patients. Actuarial primary patency in renovisceral grafts at 12, 24, and 36 months was 96.3%, 92.6%, and 90.2% respectively. At the level of the anastomosis of the graft to the superior mesenteric artery, significant flow alterations (systolic peak velocity >250 cm/s) were observed during computed flow dynamics analysis in 18.5% of cases. Overall, an additional procedure to ensure patency was required in 19 bypasses intraoperatively and three during follow-up. The presence of aortic dissection had no significant impact on debranching graft-related complications. During multivariate analysis, retropancreatic routing to CT was the only independent predictor of graft-related complications (P=0.006).
Specific visceral graft-related complications were not uncommon in our series and were often associated with clinical consequences. Hemodynamic alterations of debranching grafts were observed in particular at the level of the anastomosis with the superior mesenteric artery. Careful follow-up is mandatory in order to monitor visceral bypasses and facilitate patency when required.
PMCID: PMC4128930  PMID: 25133102
Thoracoabdominal aortic aneurysm (TAAA); hybrid repair (HR); visceral bypass; stent
14.  Complications after endovascular stent-grafting of thoracic aortic diseases 
To update our experience with thoracic aortic stent-graft treatment over a 5-year period, with special consideration for the occurrence and management of complications.
From December 2000 to June 2006, 52 patients with thoracic aortic pathologies underwent endovascular repair; there were 43 males (83%) and 9 females, mean age 63 ± 19 years (range 17–87). Fourteen patients (27%) were treated for degenerative thoracic aortic aneurysm, 12 patients (24%) for penetrating aortic ulcer, 8 patients (15%) for blunt traumatic injury, 7 patients (13%) for acute type B dissection, 6 patients (11%) for a type B dissecting aneurysm; 5 patients (10%) with thoraco-abdominal aortic aneurysms were excluded from the analyses. Fifteen patients (32%) underwent emergency treatment. Overall, mean EuroSCORE was 9 ± 3 (median 15, range 3–19). All procedures were performed in the theatre under general anesthesia. All complications occurring during hospitalisation were recorded. Follow-up protocol featured CT-A, and chest X-rays 1, 4 and 12 months after intervention, and annually thereafter.
Primary technical success was achieved in all patients; procedures never aborted because of access difficulty. Conversion to standard open repair was never required. Mean duration of the procedure was 119 ± 75 minutes (median 90, range 45–285). Mean blood loss was 254 mL (range 50–1200 mL). The mean length of the aorta covered by the SGs was 192 ± 21 mm (range 100–360). The LSA was over-stented in 17 cases (17/47, 36%). Overall 30-day operative mortality was 6.4% (3/47). Major complications included pneumonia (n = 9), cerebrovascular accidents (n = 4), arrhythmia (n = 4), acute renal failure (n = 3), and colic ischemia (n = 1). Overall, endoleak rate was 14%.
Although this report is a retrospective and not comparative analysis of thoracic aortic repair, the combined minor and major morbidity rate was lower than previous reported to results of either electively and emergency performed conventional repair.
PMCID: PMC1574296  PMID: 16968547
15.  The Sorin Freedom SOLO Stentless Tissue Valve 
Texas Heart Institute Journal  2013;40(1):50-55.
We prospectively evaluated the hemodynamic performance of the SORIN Freedom SOLO aortic bioprosthesis, a stentless bovine pericardial valve designed for supra-annular implantation.
Forty patients (mean age, 71.68 ± 5.25 yr; 29 men) with severe aortic stenosis underwent aortic valve replacement from January 2008 through August 2009. Patients were evaluated by transthoracic echocardiography and clinical examination, both preoperatively and again at 6 and 24 postoperative months. Peak and mean transvalvular gradients, end-diastolic and end-systolic diameters, interventricular septal and posterior wall thicknesses, indexed volumes of ventricular mass, degrees of aortic regurgitation, and left ventricular ejection fractions were calculated echocardiographically. The valves were implanted with single polypropylene sutures. In the early postoperative period, 1 patient (2.5%) died of multiorgan failure.
The mean aortic cross-clamp time was 86.05 ± 34.2 min. Echocardiographic peak gradients were 84.54 ± 16.85 mmHg (preoperative), 29.59 ± 6.27 mmHg (6 mo postoperative), and 24.33 ± 4.67 mmHg (24 mo postoperative) (P < 0.001); left ventricular mass indices were 176.26 ± 39.98 g/m2 (preoperative), 139.21 ± 30.1 (6 mo postoperative), and 120.51 ± 23.88 g/m2 (24 mo postoperative) (P < 0.001). During follow-up, the maximum aortic insufficiency recorded was trace, and no valve dysfunctions were observed. Temporary thrombocytopenia was documented in all patients during early postoperative follow-up (lowest level at day 3); recovery to preoperative levels occurred by day 10.
The Freedom SOLO aortic bioprosthesis is an easy-to-implant valve with excellent hemodynamic performance. The thrombocytopenia appears to be a transient laboratory finding.
PMCID: PMC3568268  PMID: 23466929
Aged; aortic stenosis/surgery; heart valve prosthesis implantation; heart valves/surgery; bioprosthesis; prosthesis design; thrombocytopenia/blood; treatment outcome
16.  Proximal clamping levels in abdominal aortic aneurysm surgery. 
Texas Heart Institute Journal  1999;26(4):264-268.
In the surgical treatment of abdominal aortic aneurysm, the single proximal cross-clamp can be placed at 3 alternative aortic levels: infrarenal, hiatal, and thoracic. We performed this retrospective study to evaluate the advantages and disadvantages of the 3 main aortic clamping locations. Eighty patients presented at our institution with abdominal aortic aneurysms from March 1993 through May 1998. Fifty of these patients had intact aneurysms and underwent elective surgery, and 30 had ruptured aneurysms that necessitated emergency surgery. Proximal aortic clamping was applied at the infrarenal level in 24 patients (22 from the intact aneurysm group, 2 from the ruptured group), at the hiatal level in 34 patients (22 intact, 12 ruptured), and at the thoracic level (descending aorta) via a limited left lateral thoracotomy in 22 patients (6 intact, 16 ruptured). Early mortality rates (within 30 days) were 4% (2 of 50 patients) among patients with intact aneurysms and 40% (12 of 30 patients) among those with ruptured aneurysms. In the 2 patients from the intact aneurysm group, proximal aortic clamps were applied at the hiatal level. In the ruptured aneurysm group, proximal aortic clamps were placed at the thoracic level in 10 patients, the infrarenal level in 1, and the hiatal level in 1. According to our study, the clinical status of the patient and the degree of operative urgency--as determined by the extent of the aneurysm--generally dictate the proximal clamp location. Patients who present with aneurysmal rupture or hypovolemic shock benefit from thoracic clamping, because it restores the blood pressure and allows time to replace the volume deficit. Infrarenal placement is advantageous in patients with intact aneurysms if there is sufficient space for the clamp between the renal arteries and the aortic aneurysm. In patients with juxtarenal aneurysms, hiatal clamping enables safe and easy anastomosis to the healthy aorta. Clamping at this level also helps prevent late anastomotic aneurysm formation, which is frequently encountered after inadvertent anastomosis of the graft to a diseased portion of the aorta. Further studies are needed in order to confirm these results.
PMCID: PMC325661  PMID: 10653253
17.  External aortic wrap for repair of type 1 endoleak☆ 
Type 1 endoleak is a rare complication after endovascular abdominal aortic aneurysm repair (EVAR) with a reported frequency up to 2.88%. It is a major risk factor for aneurysmal enlargement and rupture.
We present a case of a 68 year old gentleman who was found to have a proximal type 1 endoleak with loss of graft wall apposition on routine surveillance imaging post-EVAR. An initial attempt at endovascular repair was unsuccessful. Given the patient's multiple medical co-morbidities, which precluded the possibility of conventional graft explantation and open repair, we performed a novel surgical technique which did not require aortic cross-clamping. A double-layered Dacron wrap was secured around the infra-renal aorta with Prolene sutures, effectively hoisting the posterior bulge to allow wall to graft apposition and excluding the endoleak. Post-operative CT angiogram showed resolution of the endoleak and a stable sac size.
Several anatomical factors need to be considered when this technique is proposed including aortic neck angulation, position of lumbar arteries and peri-aortic venous anatomy. While an external wrap technique has been investigated sporadically for vascular aneurysms, to our knowledge there is only one similar case in the literature.
Provided certain anatomical features are present, an external aortic wrap is a useful and successful option to manage type 1 endoleak in high-risk patients who are unsuitable for aortic clamping.
PMCID: PMC4189073  PMID: 25217878
Endoleak; EVAR; AAA; Dacron graft
18.  Ministernotomy for aortic valve replacement: a study of the preliminary experience 
Canadian Journal of Surgery  2000;43(1):39-42.
The aim of the study was to evaluate the technical feasibility and the postoperative course of aortic valve replacement through a ministernotomy.
The Montreal Heart Institute and the Hôpital Lariboisière, Paris, France.
A case series from 2 institutions.
Fifty-one patients who underwent aortic valve replacement through a ministernotomy. The sternal incision was started at the level of the sternal notch extending down to the third or fourth intercostal space with a transverse section of the sternum at this level on both sides or limited to the right side (inverted T or L incision). Thirty-nine patients had aortic stenoses, 6 patients were operated for aortic insufficiency and 6 had mixed disease. The mean (and standard deviation) preoperative left ventricular ejection fraction was 0.56 (0.17).
Main outcome measures
Cardiac bypass time, complications and outcome.
The patients received Carbomedics and St. Jude mechanical valves, Hancock and Carpentier–Edwards bioprostheses. Thirty-eight patients were administered antegrade and retrograde cardioplegia, 10 patients ante-grade and 3 retrograde blood cardioplegia only. The mean (and standard error) cardiopulmonary bypass time and aortic cross-clamp time were 104 (38) minutes and 72 (16) minutes respectively. Two patients (4%) died and 2 patients (4%) showed evidence of a stroke after the procedure. Hospital stay averaged 8 (5) days.
We conclude that aortic valve replacement can be done through a ministernotomy approach with perioperative results similar to those obtained through a conventional sternotomy.
PMCID: PMC3788925  PMID: 10714256
19.  Mini-Flank Supra-12th Rib Incision for Open Partial Nephrectomy Compared with Laparoscopic Partial Nephrectomy and Traditional Open Partial Nephrectomy 
PLoS ONE  2014;9(2):e89155.
The purpose of this study was to report our approach of partial nephrectomy (PN) using a supra-12th rib mini-flank incision. We compared mini-incision open partial nephrectomy (MI-OPN) with open partial nephrectomy (OPN) and laparoscopic partial nephrectomy (LPN) to verify whether MI-OPN can be an alternative to OPN and LPN.
This was a retrospective single-center study including 194 patients who underwent partial nephrectomy (PN) between February 2005 and December 2010. Demographic, perioperative, and complication data were compared among the MI-OPN group, OPN group and LPN group.
No statistical differences were reported in either group for age, sex, BMI, tumour side (right or left kidney), RENAL nephrometry scores, PADUA score and preoperative eGFR. The operative time was longer in LPN group when compared with MI-OPN and OPN group (all P<0.001). The warm ischemia time of LPN group was longer than MI-OPN group (P = 0.032) and OPN group (P = 0.005). The length of stay of LPN group was shorter than OPN group (P = 0.018), but was similar to MI-OPN group (P = 0.094). The incidence of renal artery clamping was lower in OPN group when compared with MI-OPN and LPN group (all P<0.001). More estimated blood loss was found in OPN group when compared with MI-OPN group (p = 0.003) and LPN group (P = 0.014). The overall incidence of postoperative complications was similar.
The approach of MI-OPN can couple the benefits of both minimally invasive and open partial nephrectomy techniques with less estimated blood loss, shorter operative time, shorter length of stay, less postoperative complications, and a smaller incision. MI-OPN may be an effective alternative to laparoscopic or traditional open approaches, which maybe more suitable for the tumors with high RENAL nephrometry score or PADUA score.
PMCID: PMC3931681  PMID: 24586557
20.  Aortic Replacement with Sutureless Intraluminal Grafts 
Texas Heart Institute Journal  1990;17(4):302-309.
To avoid the anastomotic complications and long cross-clamp times associated with standard suture repair of aortic lesions, we have implanted sutureless intraluminal grafts in 122 patients since 1976. Forty-nine patients had disorders of the ascending aorta, aortic arch, or both: their operative mortality was 14% (7 patients), and the group's 5-year actuarial survival rate has been 64%. There have been no instances of graft dislodgment, graft infection, aortic bleeding, or pseudoaneurysm formation. Forty-two patients had disorders of the descending aorta and thoracoabdominal aorta: their early mortality was 10% (4 patients), and the group's 5-year actuarial survival rate has been 56%. There was 1 early instance of graft dislodgment, but no pseudoaneurysm formation, graft erosion, aortic bleeding, intravascular hemolysis, or permanent deficits in neurologic, renal, or vascular function. Thirty-one patients had the sutureless intraluminal graft implanted in the abdominal aortic position: their early mortality was 6% (2 patients), and the 5-year actuarial survival rate for this group has been 79%. There were no instances of renal failure, ischemic complication, postoperative paraplegia, pseudoaneurysm, or anastomotic true aneurysm.
Our recent efforts have been directed toward developing an adjustable spool that can adapt to the widest aorta or the narrowest aortic arch vessel; but in the meanwhile, the present sutureless graft yields shorter cross-clamp times, fewer intraoperative complications, and both early and late results as satisfactory as those afforded by traditional methods of aortic repair. (Texas Heart Institute Journal 1990; 17:302-9)
PMCID: PMC324940  PMID: 15227522
Anastomosis, surgical; aorta, aorta, abdominal; aorta, thoracic; aortic aneurysm/aneurysm, dissecting; blood vessel prosthesis; postoperative complications; prosthesis design; suture techniques
21.  Open Repair of Intact Thoracoabdominal Aortic Aneurysms in the ACS-NSQIP 
Journal of vascular surgery  2013;58(4):894-900.
Repair of thoracoabdominal aortic aneurysms (TAAA) is uncommon. Studies using national data report mortality rates of 20% while single institution studies report 5-8% mortality. Clinical trials are currently evaluating branched and fenestrated endografts. The purpose of this study is to establish a benchmark for future comparisons with endovascular trials using open repair of TAAA in the National Surgical Quality Improvement Program (NSQIP) database.
We identified all patients undergoing open surgical repair of intact TAAA (elective and emergent) in NSQIP 2005-2010 using CPT and ICD-9 codes. We analyzed demographics, comorbidities, 30-day mortality, postoperative complications, and length of stay. Multivariable logistic regression was used to identify predictors of mortality.
We identified 450 patients (418 elective, 32 emergent) that underwent open surgical repair of an intact TAAA. Mean age was 69.4 years, 60.7% were male, and 85.6% were white. Comorbidities included hypertension (87.1%), COPD (27.3%), prior stroke/TIA (16.7%), diabetes (11.6%), and peripheral vascular disease (9.6%). Thirty-day mortality was 10.0%. Pulmonary complications were the most common: failure to wean from ventilator (39.1%), pneumonia (23.1%), and reintubation (13.8%). Acute renal failure requiring dialysis occurred in 10.7% of patients. On multivariable analysis, emergent repair [OR 3.3, 95% CI (1.03-10.83), P=.04], age > 70 years [OR 3.5, 95% CI (1.03-7.56), P=.001], preoperative dialysis [OR 8.4, 95% CI (1.90-37.29), P= .005], cardiac complication [OR 2.9, 95% CI (1.05-8.21), P=.04] and renal complication [OR 8.4, 95% CI (3.41-20.56), P<.001] were predictive of mortality.
In this study of NSQIP hospitals, the first to analyze open surgical repair of TAAA, the 30-day mortality rate of 10.0% is similar to single institution reports. However, morbidity and mortality after open TAAA repair remain high confirming the need for less invasive procedures.
Repair of thoracoabdominal aortic aneurysms (TAAA) is uncommon. Studies using national data report mortality rates of 20% while single institution studies report 5-8% mortality. Clinical trials are currently evaluating branched and fenestrated endografts. The purpose of this study is to establish a benchmark for future comparisons with endovascular trials using open repair of TAAA in the National Surgical Quality Improvement Program (NSQIP) database.
We identified all patients undergoing open surgical repair of intact TAAA (elective and emergent) in NSQIP 2005-2010 using CPT and ICD-9 codes. We analyzed demographics, comorbidities, 30-day mortality, postoperative complications, and length of stay. Multivariable logistic regression was used to identify predictors of mortality.
We identified 450 patients (418 elective, 32 emergent) that underwent open surgical repair of an intact TAAA. Mean age was 69.4 years, 60.7% were male, and 85.6% were white. Comorbidities included hypertension (87.1%), COPD (27.3%), prior stroke/TIA (16.7%), diabetes (11.6%), and peripheral vascular disease (9.6%). Thirty-day mortality was 10.0%. Pulmonary complications were the most common: failure to wean from ventilator (39.1%), pneumonia (23.1%), and reintubation (13.8%). Acute renal failure requiring dialysis occurred in 10.7% of patients. On multivariable analysis, emergent repair [OR 3.3, 95% CI (1.03-10.83), P=.04], age > 70 years [OR 3.5, 95% CI (1.03-7.56), P=.001], preoperative dialysis [OR 8.4, 95% CI (1.90-37.29), P= .005], cardiac complication [OR 2.9, 95% CI (1.05-8.21), P=.04] and renal complication [OR 8.4, 95% CI (3.41-20.56), P<.001] were predictive of mortality.
In this study of NSQIP hospitals, the first to analyze open surgical repair of TAAA, the 30-day mortality rate of 10.0% is similar to single institution reports. However, morbidity and mortality after open TAAA repair remain high confirming the need for less invasive procedures.
PMCID: PMC3784637  PMID: 23642916
22.  Innovative Application of Available Stent Grafts in Japan in Aortic Aneurysm Treatment—Significance of Innovative Debranching and Chimney Method and Coil Embolization Procedure 
Annals of Vascular Diseases  2013;6(3):601-611.
Objective: We here describe our experience with innovative uses of these devices.
Patients and Methods: We reviewed treatment outcomes of 310 endovascular abdominal aortic repair (EVAR) and 83 thoracic endovascular aortic repair (TEVAR) cases performed between August 2007 and February 2012. We separately assessed results in elderly and high-risk patients who had a novel procedure. This group included 94 patients who underwent EVAR with IIA embolization, 10 patients who had EVAR and a renal artery chimney procedure for a short aortic neck, 20 patients who had two de-branching TEVAR or Chimney method for thoracic aortic aneurysms (TAA) and 3 patients who had debranching TEVAR for thoracic abdominal aortic aneurysms (TAAA).
Results: Of the 393 patients given stent grafts (SGs), 3 (0.8%) died in the hospital, including 1 patient with pneumonia who underwent EVAR and IIA embolization and 1 patient with a cerebral infarction who had TEVAR. Four patients (4.3%) who were treated with EVAR with internal iliac artery (IIA) embolization presented with residual buttock claudication 6 months postoperatively, and 3 patients (3.2%) had onset of ischemic enteritis; however, in all 7 patients, the condition resolved without additional intervention. In the 10 patients who had EVAR and a renal artery chimney method, the landing zone (LZ) was ≤10 mm, but neither endoleak nor renal artery occlusion was observed perioperatively or during midterm follow-up. Of the 20 patients who had a 2-debranching TEVAR, including 9 in whom the chimney method was used with the LZ in zone 0, 1 (5%) had a residual endoleak. In 3 patients with TAAA, we used SGs to cover 4 abdominal branches and bypassed the visceral artery; the outcomes were good, with all patients being ambulatory at hospital discharge.
Conclusion: Among innovative SGs treatments, the debranching procedure and the chimney method using catheterization and the coil-embolization technique provided good outcomes, as used in addition to surgical procedures. Aortic aneurysm treatment will become increasingly noninvasive with the continuing development of more innovative ways to use the SGs currently available in Japan. (*English Translation of Jpn J Vasc Surg 2012; 21: 165-173)
PMCID: PMC3793182  PMID: 24130616
aortic aneurysm; stentgraft; debranching procedure; chimney method; coil embolization
23.  Eight-Year Experience with Minimally Invasive Cardiothoracic Surgery 
World Journal of Surgery  2009;34(4):611-615.
Over the past decade, minimally invasive cardiac surgery (MICS) has emerged as an accepted approach for the management of cardiac disease that requires a surgical solution. We report the results of an 8-year, single-institution experience with MICS.
Between January 1, 2000 and December 31, 2007, a total of 910 patients underwent MICS. Major cases included aortic valve procedures (71, 7.8%), coronary artery bypass grafting (96, 10.5%), atrioseptal defect repair (103, 11.3%), and mitral valve procedures (507, 55.7%). Major outcomes of interest included the complication and mortality rates.
The mean age of the patients was 57 ± 15 years; the mean ejection fraction was 55% ± 11%; and the mean body mass index was 26.1 ± 4.9. Overall, 782 cases (85.9%) were performed through a mini-thoracotomy. Most of the cases were accomplished through central cannulation (765, 84.0%), and venous drainage was most commonly performed in a bicaval fashion (percutaneous superior vena cava and percutaneous inferior vena cava). The mean aortic cross-clamp and cardiopulmonary bypass (CPB) times were 58.1 ± 44.9 and 101.9 ± 66.8 min, respectively. Conversion to full sternotomy occurred in 10 patients, and the median length of stay in hospital was 6 days. The overall complication rate was 8.8%, and the 30-day mortality rate was 2.9%. In the multivariate logistic regression analysis, risk factors associated with in-hospital complications included age, CPB time, arterial cannulation location, conversion from off-CPB to on-CPB, hepatic insufficiency, and diabetes. In the multivariate hazards regression analysis, risk factors associated with mortality included postoperative stroke, renal failure, and sternal wound infection; CPB time; and previous surgery.
In our experience, minimally invasive approaches are effective and reproducible for a variety of cardiac operations, with acceptable operating time durations, morbidity, and mortality.
PMCID: PMC2864437  PMID: 19838752
24.  Postoperative Renal Function Preservation with Non-Ischemic Femoral Arterial Cannulation for Thoracoabdominal Aortic Repair 
Renal failure after thoracoabdominal aortic (TAAA) repair is a significant clinical problem. Distal aortic perfusion for organ and spinal cord protection requires cannulation of the left femoral artery. In 2006 we reported the finding that direct cannulation led to leg ischemia in some patients, and that this was associated with increased renal failure. Following this finding, we modified our perfusion technique to eliminate leg ischemia from cannulation. Here we present the effects of this change on postoperative renal function.
Between February 1991 and July 2008, we repaired 1464 TAAA, 1088 using distal aortic perfusion, and only those receiving distal perfusion were studied. Median age was 68 years and 378/1088 (35%) were female. In September 2006 we began to adopt a sidearm femoral cannulation technique that provides distal aortic perfusion while maintaining downstream flow to the leg. This was used in 167 (15%) patients. We measured the joint effects of preoperative glomerular filtration rate (GFR) and cannulation technique on highest postoperative creatinine, postoperative renal failure and mortality. Analysis was by multiple linear or logistic regression with interaction.
Preoperative GFR was the strongest predictor of postoperative renal dysfunction and mortality. No significant main effects of sidearm cannulation were noted. However, for peak creatinine and postoperative renal failure, strong interactions between preoperative GFR and sidearm cannulation were present, resulting in reductions of postoperative renal complications in the range of 15-20% when GFR was below 60. For normal GFR, the effect was negated or even reversed at very high levels of GFR. Mortality, though not significantly affected by sidearm cannulation, showed a similar trend to the renal outcomes.
Use of sidearm cannulation is associated with a clinically important and highly statistically significant reduction in postoperative renal complications in patients with low GFR. Reduced renal effect of skeletal muscle ischemia is the proposed mechanism. Effects among patients with good preoperative renal function are less clear. A randomized trial is needed.
PMCID: PMC2815229  PMID: 19853401
25.  Outcome of Renal Stenting for Renal Artery Coverage During Endovascular Aortic Aneurysm Repair 
Journal of Vascular Surgery  2009;49(5):1100-1106.
To determine the outcome of adjunctive renal artery stenting for renal artery coverage at the time of endovascular abdominal aortic aneurysm repair (EVAR).
Between 8/2000 to 8/2008, 29 patients underwent elective EVAR using bifurcated Zenith stent-grafts and simultaneous renal artery stenting. Renal artery stenting during EVAR was performed with endograft “encroachment” on the renal artery ostium (n = 23) or placement of a renal stent parallel to the main body of the endograft (“snorkel”, n = 8). Follow-up included routine contrast-enhanced computed tomography (CT), multi-view abdominal x-rays, and creatinine measurement at 1, 6, and 12 months, and then yearly thereafter.
31 renal arteries were stented successfully in 29 patients. All patients with planned renal artery stent placement (n=18) had a proximal neck length < 15mm. Mean proximal neck length was shorter in patients who underwent the “snorkel” technique (6.9 ± 3.1 mm) compared to those with planned endograft encroachment (9.9 ± 2.6 mm). None of the patients with unplanned endograft encroachment had neck lengths < 15mm (mean length: 26.3±10.2 mm). Mean proximal neck angulation was 42.8 ± 24.0 degrees and did not differ between the groups. One patient had a type I endoleak on completion angiography, and 2 additional patients had a type I endoleak on the first postoperative CT scan. All type I endoleaks resolved by the one-month postoperative CT scan. Primary-assisted patency of renal artery stents was 100% at a median follow-up of 12.5 months (range 2 days to 77.4 months). One patient had near occlusion of a renal artery stent noted on follow-up CT scan at 9 months; patency was restored by placement of an additional stent. One patient required dialysis following sustained hypotension from a right external iliac artery injury which resulted in prolonged post-operative bleeding. Mean creatinine at baseline was 1.1 ± 0.3 mg/dl, 1.2 ± 0.5 mg/dl at 1 month follow-up, and 1.2 ± 0.5 mg/dl at 2 years of follow-up. There were no cases of late type I endoleaks (>one month postoperatively) or stent-graft migration.
Adjunctive renal artery stenting during endovascular AAA repair using the “encroachment” and “snorkel” techniques is safe and effective. Short and medium term primary patency rates are excellent, but careful follow-up is needed to determine the durability of these techniques.
PMCID: PMC3276369  PMID: 19233597

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