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1.  CT Findings of Risk Factors for Persistent Type II Endoleak from Inferior Mesenteric Artery to Determine Indicators of Preoperative IMA Embolization 
Annals of Vascular Diseases  2014;7(3):274-279.
Purpose: To identify the computed tomography (CT) findings of persistent type II endoleak from the inferior mesenteric artery (IMA) which indicate the need for preoperative IMA embolization.
Materials and Methods: Included were 120 patients (96 males, 49–93 years old, mean: 77.7) who underwent endovascular aortic aneurysm repair (EVAR) between June 2007 and October 2010. The relationship between persistent type II endoleak and CT findings of IMA orifice was examined.
Results: CT showed no type II endoleak from IMA in 106 patients (89%; Group N), and transient type II endoleak from IMA in 10 patients (8.3%; Group T). CT showed persistent type II endoleak from IMA in 4 patients (3.3%; Group P) and three of them underwent reintervention. Univariate Cox-Mantel test analysis indicated that stenosis (p = 0.0003) and thrombus (p = 0.043) in IMA orifice were significant factors for persistent type II endoleak. The ratios of patients with proximal IMA more than 2.5 mm diameter in Groups N, Y, and P were 26/106 (24%), 5/10 (50%) and 4/4 (100%), respectively.
Conclusion: Indicators for embolization of IMA prior to EVAR for the prevention of type II endoleak appear to be: (1) more than 2.5 mm in diameter and (2) no stenosis due to calcification or mural thrombus in IMA orifice.
doi:10.3400/avd.oa.14-00008
PMCID: PMC4180689  PMID: 25298829
CT; inferior mesenteric artery; type II endoleak; endovascular aneurysm repair
2.  Influencing Factors for Abdominal Aortic Aneurysm Sac Shrinkage and Enlargement after EVAR: Clinical Reviews before Introduction of Preoperative Coil Embolization 
Annals of Vascular Diseases  2014;7(3):280-285.
Background: We previously reported effectiveness of coil embolization (CE) to aortic branched vessels before endovascular aortic repair (EVAR) for abdominal aortic aneurysm (AAA) because of significant shrinkage of aneurysmal sac. In this study, we investigated EVAR cases to clarify influential factors of aneurysmal shrinkage and enlargement.
Methods: 148 consecutive cases before the introduction of CE were retrospectively reviewed based on the presence of PT2EL (persistent type 2 endoleak) and change in sac diameter after EVAR by multivariate analysis.
Results: (A) PT2EL risk factors were patent inferior mesenteric artery (IMA) and thinner mural thrombus inside aneurysmal sac. (B) Sac enlargement risk factors were antiplatelet intake, PT2EL, and female gender. (C) Sac shrinkage predictive factors were the absences of thoracic aortic aneurysm, antiplatelet intake, PT2EL, and coronary artery disease.
Conclusion: CE to IMA was considered to be effective because patent IMA and antiplatelet intake were significant risk factors for sac enlargement. So, more meticulous therapeutic strategy, including treatment priority (AAA first or CAD first) and choice of treatment (EVAR vs. AAA) based on anatomical features of AAA was required to improve late outcomes.
doi:10.3400/avd.oa.14-00050
PMCID: PMC4180690  PMID: 25298830
EVAR; endoleak; sac enlargement and shrinkage; coil embolization
3.  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.
Method
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
Summary
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
4.  Endovascular Repair of Descending Thoracic Aortic Aneurysm 
Executive Summary
Objective
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
Objectives
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
Mortality
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.
Conclusions
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.  Clinical significance of type I endoleak on completion angiography 
Purpose
Type I endoleak is known to be associated with sac enlargement and occasional rupture, therefore, the treatment of type I endoleak is recommended at the time of diagnosis. The aim of this study was to identify the significance of early type I endoleak found on completion angiography.
Methods
Between January 2000 and December 2012, a total of 86 patients underwent endovascular abdominal aortic aneurysm repair (EVAR) and 10 patients (11.6%) were diagnosed with type Ia endoleak on completion angiography. Clinical and radiologic data were reviewed retrospectively.
Results
Of the 10 patients, two underwent EVAR with custom-made stent-grafts in the initial stage and both of them needed immediate treatment: one case involved open repair while the other involved insertion of an additional stent-graft. In 8 patients, the amount of leakage decreased after repeated balloon molding. They were managed conservatively and followed up with computed tomography angiography within 2 weeks after EVAR. In 7 of the 8 cases, type Ia endoleaks disappeared. In one patient with a persistent endoleak and a folded posterior wall of the stent-graft, coil embolization was performed 1 week after EVAR. With a median follow-up of 12 months (range, 1-61 months), no patients showed recurrence of type I endoleak or sac expansion.
Conclusion
Type I endoleaks diagnosed on completion angiography sealed spontaneously in 7 of 10 patients (70.0%). In cases of decreased amounts of leakage after balloon molding, simple observation may be an alternative to repetitive procedures. The long-term follow-up of patients with self-sealed type I endoleaks is mandatory.
doi:10.4174/astr.2014.86.2.95
PMCID: PMC3994602  PMID: 24761415
Endovascular aneurysm repair; Abdominal aortic aneurysm; Endoleak
6.  Endovascular Repair of Abdominal Aortic Aneurysm 
EXECUTIVE SUMMARY
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.
OBJECTIVE
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).
BACKGROUND
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
7.  CT- and Fluoroscopy-Guided Percutaneous Transabdominal Embolization of Type II Endoleak 
The Eurasian Journal of Medicine  2013;45(2):132-134.
We report a case of a 79-year-old male patient who was treated 3 years previously at another hospital for an abdominal aortic aneurysm with a maximal diameter of 80 mm. After the treatment control period, computed tomography imaging revealed a type II endoleak and no progression in the size of the aneurysm sac. Selective injection of the superior mesenteric artery revealed that the endoleak was filled by the inferior mesenteric artery via the marginal artery. However, it was not possible to access using retrograde catheterization. We decided to treat the type II endoleak percutaneously. Embolization was performed at the tomography table using fluoroscopy with a mobile C-arm, and the puncture was performed transabdominally because there was no access to the sac via a translumbar approach. Under fluoroscopic guidance, various diameter/length coils were deployed. Follow-up computed tomography scans confirmed the collapsed aneurysm sac. When other conventional endovascular methods have failed, percutaneous transabdominal treatment of a type II endoleak with sac enlargement offers an alternative treatment method.
doi:10.5152/eajm.2013.26
PMCID: PMC4261490  PMID: 25610266
Abdominal aortic aneurysm; embolization; type II endoleak
8.  Evaluation and Treatment of Suspected Type II Endoleaks in Patients with Enlarging Abdominal Aortic Aneurysms 
Purpose
To evaluate angiographic diagnosis and embolotherapy of patients with enlarging abdominal aortic aneurysms and computed tomographic (CT) diagnosis of type II endoleak.
Materials and Methods
A retrospective review was performed of all patients referred to a single vascular and interventional radiology section from January 1, 2003, to June 1, 2011, with a diagnosis of enlarging aneurysm and type II endoleak. Twenty-five patients underwent 40 procedures between 12 and 82 months after endograft insertion (mean, 48 mo) for diagnosis and/or treatment of endoleaks.
Results
Type II endoleaks were treated with cyanoacrylate, coils, and ethylene vinyl alcohol copolymer in 16 patients. Technical success rate was 88% (14 of 16 patients) and clinical success rate was 100% (16 of 16 patients). Aneurysm growth was arrested in all cases over a mean follow-up of 27.5 months (range, 6 – 88 mo). Endoleaks in nine patients were misclassified on CT; two had type I endoleaks and seven had type III endoleaks. Four of the nine patients (two type I endoleaks and two type III endoleaks) were correctly classified after initial angiography. The other five type III endoleaks were correctly classified on CT after coil embolization of the inferior mesenteric artery. Direct embolization was performed via sac puncture with ethylene vinyl alcohol copolymer in two of the latter five patients and eliminated endoleaks in both.
Conclusions
Aneurysm growth caused by type II endoleaks was arrested by embolization. CT misclassification occurred relatively commonly; type III endoleaks purported to be type II endoleaks were found in 28% of patients (seven of 25).
doi:10.1016/j.jvir.2012.04.003
PMCID: PMC3506247  PMID: 22609291
9.  Outcome of Renal Stenting for Renal Artery Coverage During Endovascular Aortic Aneurysm Repair 
Journal of Vascular Surgery  2009;49(5):1100-1106.
Objective
To determine the outcome of adjunctive renal artery stenting for renal artery coverage at the time of endovascular abdominal aortic aneurysm repair (EVAR).
Methods
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.
Results
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.
Conclusions
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.
doi:10.1016/j.jvs.2008.11.060
PMCID: PMC3276369  PMID: 19233597
10.  Successful treatment of type I endoleak of common iliac artery with balloon expandable stent (Palmaz XL stent) during endovascular aneurysm repair 
Type 1 endoleak of common iliac artery (type Ib endoleak) should be treated during endovascular aneurysm repair (EVAR). An 86-year-old female was diagnosed with abdominal aortic aneurysm measuring 6.6 cm in diameter and right internal iliac artery aneurysm measuring 4.0 cm in diameter. She underwent EVAR after right internal iliac artery embolization. There was type Ib endoleak, which was repaired by balloon-expandable stent, Palmaz XL stent (Cordis). We report successful treatment of type Ib endoleak with Palmaz XL stent, which may be considered as an alternative option for type Ib endoleak after EVAR.
doi:10.4174/jkss.2012.82.1.59
PMCID: PMC3268146  PMID: 22324049
Abdominal aortic aneurysm; Endovascular procedure; Endoleak
11.  Transradial approach for the endovascular treatment of type I endoleak after aortic aneurysm repair: a case report 
BMC Surgery  2013;13(Suppl 2):S47.
Background
Endovascular repair of aortic aneurysms (EVAR) is obtained through the positioning of an aortic stent-graft, which excludes the aneurysmatic dilation. Type I endoleak is the most common complication, and it is caused by an incompetent proximal or distal attachment site, causing the separation between the stent-graft and the native arterial wall, and in turn creating direct communication between the aneurysm sac and the systemic arterial circulation. Endoleak occurrence is associated with high intrasac pressures, and requires a quick repair to prevent abdominal aortic aneurysm rupture.
Case presentation
We report the first case of a 80-year-old man undergoing percutaneous closure of a peri-graft endoleak (type I) by transcatheter embolization through radial arterial access.
Conclusion
The transradial approach has been shown to be a safe and effective alternative to the traditional transfemoral approach. A decrease in vascular complications and improved patient comfort are the primary benefits of this technique in patients with previous EVAR.
doi:10.1186/1471-2482-13-S2-S47
PMCID: PMC3851154  PMID: 24267381
12.  External aortic wrap for repair of type 1 endoleak☆ 
INTRODUCTION
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.
PRESENTATION OF CASE
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.
DISCUSSION
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.
CONCLUSION
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.
doi:10.1016/j.ijscr.2014.08.008
PMCID: PMC4189073  PMID: 25217878
Endoleak; EVAR; AAA; Dacron graft
13.  Static sac size with a type II endoleak post-endovascular abdominal aortic aneurysm repair: surveillance or embolization? 
A best evidence topic was written according to a structured protocol. The question addressed was whether embolization is superior to surveillance for a type II endoleak associated with a static sac size post-endovascular abdominal aortic aneurysm repair (EVAR). Four hundred and sixty-one papers were identified, of which 10 papers presented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, and relevant outcomes and results are tabulated. A review of the available literature suggests that most type II endoleaks are innocuous and will seal spontaneously during the long-term follow-up, even when they persist for more than 6 months. An analysis of the large European Collaborators on Stent-Graft Techniques for Aortic Aneurysm Repair (EUROSTAR) registry that includes prospective data on 2463 patients from 87 European hospitals showed that type II endoleaks were not associated with an increased risk of rupture; this correlates well with the large single-centre studies included in this review. Based on the available evidence, we conclude that the management of most isolated type II endoleaks should be conservative—with close radiological follow-up—even when persistent, with intervention restricted to theoese associated with sac enlargement >5 mm over a 6-month period or >10 mm when compared with pre-EVAR diameter.
doi:10.1093/icvts/ivs201
PMCID: PMC3422929  PMID: 22617500
Abdominal aortic aneurysm; Endovascular repair; Endoleak; Conservative management
14.  Ten-year results of endovascular abdominal aortic aneurysm repair from a large multicenter registry 
Journal of vascular surgery  2013;58(2):324-332.
Objective
To assess outcomes after endovascular abdominal aortic aneurysm repair (EVAR) in an integrated health care system.
Methods
Between 2000 and 2010, 1736 patients underwent EVAR at 17 centers. Demographic data, comorbidities, and outcomes of interest were collected. EVAR in patients presenting with ruptured or symptomatic aneurysms was categorized as urgent; otherwise, it was considered elective. Primary outcomes were mortality and aneurysm-related mortality (ARM). Secondary outcomes were change in aneurysm sac size, endoleak status, major adverse events, and reintervention.
Results
Overall, the median age was 76 years (interquartile range, 70–81 years), 86% were male, and 82% were Caucasian. Most cases (93.8%) were elective, but urgent use of EVAR increased from 4% in the first 5 years to 7.3% in the last 5 years of the study period. Mean aneurysm size was 5.8 cm. Patients were followed for an average of 3 years (range, 1–11 years); 8% were lost to follow-up. Intraoperatively, 4.5% of patients required adjunctive maneuvers for endoleak, fixation, or flow-limiting issues. The 30-day mortality rate was 1.2%, and the perioperative morbidity rate was 6.6%. Intraoperative type I and II endoleaks were uncommon (2.3% and 9.3%, respectively). Life-table analysis at 5 years demonstrated excellent overall survival (66%) and freedom from ARM (97%). Postoperative endoleak was seen in 30% of patients and was associated with an increase in sac size over time. Finally, the total reintervention rate was 15%, including 91 instances (5%) of revisional EVAR. The overall major adverse event rate was 7.9% and decreased significantly from 12.3% in the first 5 years to 5.6% in the second 5 years of the study period (P < .001). Overall ARM was worse in patients with postoperative endoleak (4.1% vs 1.8%; P < .01) or in those who underwent reintervention (7.6% vs 1.6%; P < .001).
Conclusions
Results from a contemporary EVAR registry in an integrated health care system demonstrate favorable perioperative outcomes and excellent clinical efficacy. However, postoperative endoleak and the need for reintervention continue to be challenging problems for patients after EVAR. (J Vasc Surg 2013;58:324–32.)
doi:10.1016/j.jvs.2013.01.051
PMCID: PMC3930460  PMID: 23683376
15.  Aneurysmal degeneration and type Ib endoleak with proximal aneurysm rupture: A case report, review of literature and technical suggestions 
Introduction
Despite the reduction in mortality incidences of AAA in proportion to increased use of EVAR, the natural history of aneurysms with the presence of an endoleak post EVAR remains unclear. With a cumulative AAA rupture incidence of 2% at six years post EVAR, the lack of an immediate endoleak is not an indicator of success.
Case report
We present a case of an 80-year-old man who presented to the emergency department with generalised abdominal pain and hypotension. Four years earlier he had underwent an EVAR for a 6 cm infra-renal AAA. The computed tomography angiogram (CTA) illustrated aneurysmal dilatation of the left common iliac artery with extensive retroperitoneal haemorrhage. The patient was transferred to the operating room for an endovascular repair but due to significant episodes of haemodynamic instability, an emergency exploratory laparotomy was performed. To our surprise, there was a left-sided infra-renal anterolateral rupture of the aneurysm sac. The stent was explanted with difficulty from its fixed proximal aortic section down to left-sided common iliac artery. The fixed bare portion of the stent in the proximal aorta and in the right common iliac artery was left in-situ and the rest was integrated to a trouser graft with an end-to-end technique.
Discussion
On detection of an endoleak, the aim should focus on their endovascular management, as open conversions are associated with high mortality and morbidity. Conclusion: If open conversion is indicated, all technical aspects of the repair including partial stent extraction should be considered for best outcome.
doi:10.1016/j.amsu.2014.02.018
PMCID: PMC4268475  PMID: 25568785
Abdominal aortic aneurysm (AAA); Endovascular aneurysm repair (EVAR); Endoleak; Technical suggestion; Explantation of endograft
16.  Early and delayed rupture after endovascular abdominal aortic aneurysm repair in a 10-year multicenter registry 
Journal of vascular surgery  2014;60(5):1146-1152.
Objective
Rupture after abdominal endovascular aortic aneurysm repair (EVAR) is a function of graft maintenance of the seal and fixation. We describe our 10-year experience with rupture after EVAR.
Methods
From 2000 to 2010, 1736 patients with abdominal aortic aneurysm (AAA) from 17 medical centers underwent EVAR in a large, regional integrated health care system. Preoperative demographic and clinical data of interest were collected and stored in our registry. We retrospectively identified patients with postoperative rupture, characterized as “early” and “delayed” rupture (≤30 days and >30 days after the initial EVAR, respectively), and identified predictors associated with delayed rupture.
Results
The overall follow-up rate was 92%, and the median follow-up was 2.7 years (interquartile range, 1.2–4.4 years) in these 1736 EVAR patients. We identified 20 patients with ruptures; 70% were male, the mean age was 79 years, and mean AAA size at the initial EVAR was 6.3 cm. Six patients underwent initial EVAR for rupture (n = 2) or symptomatic presentation (n = 4). Of the 20 post-EVAR ruptures, 25% (five of 20) were early, all occurring within 2 days after the initial EVAR. Of these five patients, four had intraoperative adverse events leading directly to rupture, with one type I and one type III endoleak. Of the five early ruptures, four patients underwent endovascular repair and one received repair with open surgery, resulting in two perioperative deaths. Among the remaining 15 patients, the median time from initial EVAR to rupture was 31.1 months (interquartile range, 13.8–57.3 months). Most of these delayed ruptures (10 of 15) were preceded by AAA sac increases, including three patients with known endoleaks who underwent reintervention. At the time of delayed rupture, nine of 15 patients had new endoleaks. Among all 20 patients, six patients did not undergo repair (all delayed patients) and died, nine underwent repeated EVAR, and five had open repair. For patients who underwent repair for delayed rupture, mortality at 30 days and 1 year were 44.4% and 66.7%, respectively. Multivariable Cox regression analysis identified age 80 to 89 (hazard ratio, 3.3; 95% confidence interval, 1.1–9.4; P =.03), and symptomatic or ruptured initial indication for EVAR (hazard ratio, 7.4; 95% confidence interval, 2.2–24.8; P < .01) as significant predictors of delayed rupture.
Conclusions
Rupture after EVAR is a rare but devastating event, and mortality after repair exceeds 60% at 1 year. Most delayed cases showed late AAA expansion, thereby implicating late loss of seal and increased endoleaks as the cause of rupture in these patients and mandating vigilant surveillance.
doi:10.1016/j.jvs.2014.05.046
PMCID: PMC4331642  PMID: 24957409
17.  Technical tips and procedural steps in endovascular aortic aneurysm repair with concomitant recanalization of iliac artery occlusions 
SpringerPlus  2013;2:605.
Purpose
The goal of this paper is to describe our technical strategy and procedural steps for endovascular aneurysm repair (EVAR) when performed with concomitant recanalization of the iliac artery occlusion.
Materials and methods
Three octogenarians having abdominal aortic aneurysm (AAA)/common iliac artery aneurysms (CIAA) with unilateral external iliac artery (EIA) occlusion underwent EVAR with recanalization of the occluded iliac arteries. Crossing the iliac artery occlusions was attempted in a retrograde approach using a 0.035 inch-hydrophilic guidewire. After passage of a guidewire, predilation was performed using 6mm balloon. Then a 12-Fr sheath was advanced via the occluded EIA for contralateral iliac limb delivery. Internal iliac artery embolization was subsequently performed as needed. A self-expanding stent was then placed in the occluded EIA after EVAR.
Results
Recanalization of the EIA occlusion, followed by stentgraft delivery through the occlusion and EVAR, was successfully performed in all three patients. Penetration of the occluded EIA was successfully achieved only by retrograde approach in two patients, and by bidirectional approach in the other patient. No perioperative complication or death occurred. Postoperative CT showed no type I or III endoleaks in the aneurysms and patent iliac arteries in all patients.
Conclusions
Total endovascular repairs were successfully performed for three patients with AAA and concomitant unilateral EIA occlusions. The proposed steps described in this report might reduce the complication rate and enhance the technical success rate associated with this procedure.
doi:10.1186/2193-1801-2-605
PMCID: PMC3837076  PMID: 24294549
Abdominal aortic aneurysm; Endovascular aneurysm repair; Iliac artery occlusion; Peripheral arterial disease; Stent placement
18.  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)
doi:10.3400/avd.cr.13-00070
PMCID: PMC3793182  PMID: 24130616
aortic aneurysm; stentgraft; debranching procedure; chimney method; coil embolization
19.  Preoperative Coil Embolization to Aortic Branched Vessels for Prevention of Aneurysmal Sac Enlargement Following EVAR: Early Clinical Result 
Annals of Vascular Diseases  2013;6(2):175-179.
Objective: Persistent Type 2 endoleaks (PT2) after endovascular aortic aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA) are associated with increased adverse outcomes, including aneurysmal sac enlargement and rupture. The aim of this study was to report early clinical outcomes of coil embolization (CE) to aortic branched vessels prior to EVAR and assess the effectiveness of this strategy in terms of prevention of sac growth due to PT2.
Materials and Methods: Between May 2007 and April 2012, EVAR was performed for 215 cases, divided into two groups (150 cases in Group A, before introduction of CE; 21 in Group B, receiving CE before EVAR). Early clinical outcomes were compared between groups.
Results: Fifty percent of cases in Group B had a marked reduction of aneurysmal sac diameter based on multi-detector row computed tomographic angiography (MDCTA) findings at the 6-month follow-up after EVAR, whereas, only 25% of cases in Group A had shrinkage of the aneurysmal sac during the same time period after EVAR.
Conclusion: This strategy has the possibility of improving late outcomes of EVAR by reducing endoleak volumes beforehand.
doi:10.3400/avd.oa.12.00079
PMCID: PMC3692987  PMID: 23825498
EVAR; endoleaks; coil embolization
20.  Long-Term Results of Aortic Banding for Complex Infrarenal Neck Anatomy and Type I Endoleak after Endovascular Abdominal Aortic Aneurysm Repair 
Texas Heart Institute Journal  2012;39(6):799-805.
For many patients with abdominal aortic aneurysm, unsuitable anatomy of the infrarenal aortic neck precludes endovascular aortic aneurysm repair or causes type I endoleak after the procedure. In an attempt to overcome these challenges, we retrospectively examined the usefulness of aortic banding as an adjunctive procedure to endovascular repair in 8 patients who had an abdominal aortic aneurysm with a complex infrarenal aortic neck. The procedures were performed with the patients under general anesthesia and involved making an 8-cm upper-midline laparotomy incision to expose the aneurysmal aorta. Three patients underwent aortic banding before endovascular repair; the other 5 underwent banding after the repair because of persistent type I endoleak. After banding, the abdominal aortic aneurysm was successfully excluded in all 8 patients. Long-term follow-up (mean, 38 ± 20 mo) revealed no type I endoleak and no procedure-related complications. In patients who have an abdominal aortic aneurysm with complex infrarenal neck anatomy or a refractory type I endoleak, performing aortic banding as an adjunctive procedure to endovascular aortic repair appears to be a safe strategy with good long-term results.
PMCID: PMC3528212  PMID: 23304016
Aortic aneurysm, abdominal/complications/surgery; blood vessel prosthesis implantation/adverse effects/methods; patient selection; postoperative complications; risk factors; stents; treatment outcome; vascular surgical procedures/instrumentation
21.  Occlusion of the common and internal iliac arteries for aortoiliac aneurysm repair: experience with the Amplatzer vascular plug 
Canadian Journal of Surgery  2009;52(6):E276-E280.
Background
We sought to evaluate and describe our centre’s experience with the Amplatzer vascular plug (AVP) for the occlusion of common and internal iliac arteries (CIA; IIA) during endovascular aortic aneurysm repair (EVAR).
Methods
We performed a retrospective analysis of 20 consecutive patients between October 2006 and December 2007, who underwent occlusion of the CIA or IIA before or during EVAR to prevent endoleak.
Results
Among these 20 patients, 21 occlusion procedures occurred and 20 were successful. In the only unsuccessful case, the patient had EVAR, but occlusion with an AVP was not possible because of severe narrowing at the origin of the vessel. Of the successfully treated patients, 2 presented with ruptured aneurysms, whereas the others had elective procedures. Eleven patients received aortouni-iliac grafts and femoral–femoral bypass, and 9 patients received a bifurcated stent graft. In 5 patients, the AVP occlusion and EVAR procedures were staged; in these cases occlusion occurred first, followed by EVAR on average 29 (standard deviation [SD] 23) days later. We deployed 7 AVPs in the CIA, whereas 13 were deployed in the IIA. The average diameter of the vessels occluded was 10 (SD 1) mm and the average size of the device used was 13 (SD 1) mm, representing a device diameter 28% (SD 2%) greater than the vessel diameter. We used a single device in 18 patients, whereas 2 devices were deployed in the same artery in 2 patients. Four patients underwent concomitant coil embolization. On follow-up computed tomography (CT) scans, all occlusion procedures were clinically successful. At the 14-month (SD 1 mo) follow-up, 4 patients had a small type-II endoleak unrelated to the occlusion procedure and 1 had a type-I endoleak that required graft limb extension. Four patients had buttock claudication but none had changes in sexual function, ischemic complications or device dislodgement on CT scans.
Conclusion
The AVP is a safe and effective method to occlude the CIA and IIA in patients undergoing EVAR.
PMCID: PMC2792393  PMID: 20011164
22.  Endoluminal Abdominal Aortic Aneurysm Repair 
Texas Heart Institute Journal  2010;37(1):19-24.
Endovascular abdominal aortic aneurysm repair (EVAR) is an attractive alternative to open surgical repair. Distal endograft migration and type 1 endoleak are recognized to be the 2 main complications of EVAR. First-generation endografts had a stronger propensity for distal migration, modular component separation, thrombosis, and loss of structural integrity. Substantial progress has been made in recent years with 2nd- and 3rd-generation devices to prevent these complications. Some of the most common predictors of endograft failure are angulated and short infrarenal necks, large-diameter necks, and thrombus in the aneurysmal sac. The purpose of this study is to describe and review our experience in using innovative techniques and a newer generation of endografts to prevent distal migration and type 1 endoleak in patients with challenging infrarenal neck anatomy. The use of these innovative EVAR techniques and the new generation of endografts in patients with challenging infrarenal neck anatomy has yielded encouraging procedural and intermediate-term results.
PMCID: PMC2829788  PMID: 20200623
Aneurysm, dissecting; aorta, abdominal; aortic aneurysm; aortic diseases; blood vessel prosthesis implantation; foreign-body migration; prosthesis design; stents
23.  Evaluation of Texture for Classification of Abdominal Aortic Aneurysm After Endovascular Repair 
Journal of Digital Imaging  2011;25(3):369-376.
The use of the endovascular prostheses in abdominal aortic aneurysm has proven to be an effective technique to reduce the pressure and rupture risk of aneurysm. Nevertheless, in a long-term perspective, complications such as leaks inside the aneurysm sac (endoleaks) could appear causing a pressure elevation and increasing the danger of rupture consequently. At present, computed tomographic angiography (CTA) is the most common examination for medical surveillance. However, endoleak complications cannot always be detected by visual inspection on CTA scans. The investigation on new techniques to detect endoleaks and analyse their effects on treatment evolution is of great importance for endovascular aneurysm repair (EVAR) technique. The purpose of this work was to evaluate the capability of texture features obtained from the aneurysmatic thrombus CT images to discriminate different types of evolutions caused by endoleaks. The regions of interest (ROIs) from patients with different post-EVAR evolution were extracted by experienced radiologists. Three techniques were applied to each ROI to obtain texture parameters, namely the grey level co-occurrence matrix (GLCM), the grey level run length matrix (GLRLM) and the grey level difference method (GLDM). The results showed that GLCM, GLRLM and GLDM features presented a good discrimination ability to differentiate between favourable or unfavourable evolutions. GLCM was the most efficient in terms of classification accuracy (93.41% ± 0.024) followed by GLRLM (90.17% ± 0.077) and finally by GLDM (81.98% ± 0.045). According to the results, we can consider texture analysis as complementary information to classified abdominal aneurysm evolution after EVAR.
doi:10.1007/s10278-011-9417-7
PMCID: PMC3348989  PMID: 21901536
Aneurysm; EVAR; Texture features; Neural network
24.  Percutaneous Transabdominal Approach for the Treatment of Endoleaks after Endovascular Repair of Infrarenal Abdominal Aortic Aneurysm 
Korean Journal of Radiology  2009;11(1):107-114.
Objective
The purpose of this study was to evaluate the technical feasibility and clinical efficacy of percutaneous transabdominal treatment of endoleaks after endovascular aneurysm repair.
Materials and Methods
Between 2000 and 2007, six patients with type I (n = 4) or II (n = 2) endoleaks were treated by the percutaneous transabdominal approach using embolization with N-butyl cyanoacrylate with or without coils. Five patients underwent a single session and one patient had two sessions of embolization. The median time between aneurysm repair and endoleak treatment was 25.5 months (range: 0-84 months). Follow-up CT images were evaluated for changes in the size and shape of the aneurysm sac and presence or resolution of endoleaks. The median follow-up after endoleak treatment was 16.4 months (range: 0-37 months)
Results
Technical success was achieved in all six patients. Clinical success was achieved in four patients with complete resolution of the endoleak confirmed by follow-up CT. Clinical failure was observed in two patients. One eventually underwent surgical conversion, and the other was lost to follow-up. There were no procedure-related complications.
Conclusion
The percutaneous transabdominal approach for the treatment of type I or II endoleaks, after endovascular aneurysm repair, is an alternative method when conventional endovascular methods have failed.
doi:10.3348/kjr.2010.11.1.107
PMCID: PMC2799639  PMID: 20046501
Abdominal aortic aneurysm; Endovascular aneurysm repair; Endoleak; Embolization; N-butyl cyanoacrylate
25.  Ischemic Colitis Following Transarterial Embolization for Type 2 Endoleak of EVAR: Report of a Case 
Annals of Vascular Diseases  2012;5(1):92-95.
A 71 year old man was diagnosed to have enlargement of abdominal aortic aneurysm due to type 2 endoleak two years after endovascular aneurysm repair (EVAR). 3D-CT demonstrated a type 2 endoleak that originated from the superior mesenteric artery that fed the inferior mesenteric artery and the right iliolumbar artery that flowed into the 4th lumbar artery. Transarterial embolization was performed by means of N-butyl-2-cyanoacrylate (NBCA). After the treatment, he suffered ischemic colitis that extended from the sigmoid colon to the descending colon. Conservative treatment was mainly performed, and clinical improvement was observed over time. He was discharged after 73 postoperative days.
doi:10.3400/avd.cr.11.00081
PMCID: PMC3595925  PMID: 23555495
type 2 endoleak; transarterial embolization; ischemic colitis

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