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1.  Perioperative visual loss after spine surgery 
World Journal of Orthopedics  2014;5(2):100-106.
Perioperative visual loss (POVL) is an uncommon, but devastating complication that remains primarily associated with spine and cardiac surgery. The incidence and mechanisms of visual loss after surgery remain difficult to determine. According to the American Society of Anesthesiologists Postoperative Visual Loss Registry, the most common causes of POVL in spine procedures are the two different forms of ischemic optic neuropathy: anterior ischemic optic neuropathy and posterior ischemic optic neuropathy, accounting for 89% of the cases. Retinal ischemia, cortical blindness, and posterior reversible encephalopathy are also observed, but in a small minority of cases. A recent multicenter case control study has identified risk factors associated with ischemic optic neuropathy for patients undergoing prone spinal fusion surgery. These include obesity, male sex, Wilson frame use, longer anesthetic duration, greater estimated blood loss, and decreased percent colloid administration. These risk factors are thought to contribute to the elevation of venous pressure and interstitial edema, resulting in damage to the optic nerve by compression of the vessels that feed the optic nerve, venous infarction or direct mechanical compression. This review will expand on these findings as well as the recently updated American Society of Anesthesiologists practice advisory on POVL. There are no effective treatment options for POVL and the diagnosis is often irreversible, so efforts must focus on prevention and risk factor modification. The role of crystalloids versus colloids and the use of α-2 agonists to decrease intraocular pressure during prone spine surgery will also be discussed as a potential preventative strategy.
PMCID: PMC4017302  PMID: 24829872
Perioperative visual loss; Ischemic optic neuropathy; Central retinal artery occlusion; Cortical blindness; Posterior reversible encephalopathy; Spine surgery; Prone positioning
2.  Positioning patients for spine surgery: Avoiding uncommon position-related complications 
World Journal of Orthopedics  2014;5(4):425-443.
Positioning patients for spine surgery is pivotal for optimal operating conditions and operative-site exposure. During spine surgery, patients are placed in positions that are not physiologic and may lead to complications. Perioperative peripheral nerve injury (PPNI) and postoperative visual loss (POVL) are rare complications related to patient positioning during spine surgery that result in significant patient disability and functional loss. PPNI is usually due to stretch or compression of the peripheral nerve. PPNI may present as a brachial plexus injury or as an isolated injury of single nerve, most commonly the ulnar nerve. Understanding the etiology, mechanism and pattern of injury with each type of nerve injury is important for the prevention of PPNI. Intraoperative neuromonitoring has been used to detect peripheral nerve conduction abnormalities indicating peripheral nerve stress under general anesthesia and to guide modification of the upper extremity position to prevent PPNI. POVL usually results in permanent visual loss. Most cases are associated with prolonged spine procedures in the prone position under general anesthesia. The most common causes of POVL after spine surgery are ischemic optic neuropathy and central retinal artery occlusion. Posterior ischemic optic neuropathy is the most common cause of POVL after spine surgery. It is important for spine surgeons to be aware of POVL and to participate in safe, collaborative perioperative care of spine patients. Proper education of perioperative staff, combined with clear communication and collaboration while positioning patients in the operating room is the best and safest approach. The prevention of uncommon complications of spine surgery depends primarily on identifying high-risk patients, proper positioning and optimal intraoperative management of physiological parameters. Modification of risk factors extrinsic to the patient may help reduce the incidence of PPNI and POVL.
PMCID: PMC4133449  PMID: 25232519
Spine surgery; Complication; Position; Nerve injury; Visual loss
3.  Postoperative Vision Loss after Spine Surgery: A Single-Institution Case-Control Comparison 
The Ochsner Journal  2014;14(2):179-183.
Postoperative vision loss (POVL) after spine surgery is a rare but devastating outcome. We present the first case-control study from a single institution for POVL with the diagnoses of ischemic optic neuropathy or central vision loss after complex spine surgery.
POVL cases following spine surgeries between December 1995 and December 2010 at the Cleveland Clinic were identified retrospectively using administrative codes. Each instance of POVL was matched to 5 case-control patients based on age, gender, body mass index, systolic blood pressure, diastolic blood pressure, mean arterial pressure, and hematocrit. Duration of anesthesia, fluid volumes, and hemodynamic measurements were then compared between POVL cases and control cases using Wilcoxon rank sum test.
Six patients developed POVL. These patients had significantly greater blood loss (P=0.002, Wilcoxon test) and a significantly greater volume of red blood cells transfused (P=0.006) than the control patients. No other intraoperative measures differed significantly after Bonferroni correction for multiple outcomes.
We found that patients with POVL had significantly greater blood loss and significantly more red blood cell transfusions than their matched controls.
PMCID: PMC4052583  PMID: 24940126
Optic neuropathy–ischemic; spinal fusion; surgical procedures–operative; vision–ocular
4.  Perioperative visual loss in ocular and nonocular surgery 
Incidence estimates for perioperative vision loss (POVL) after nonocular surgery range from 0.013% for all surgeries up to 0.2% following spine surgery. The most common neuro-ophthalmologic causes of POVL are the ischemic optic neuropathies (ION), either anterior (AION) or posterior (PION). We identified 111 case reports of AION following nonocular surgery in the literature, with most occurring after cardiac surgery, and 165 case reports of PION following nonocular surgery, with most occurring after spine surgery or radical neck dissection. There were an additional 526 cases of ION that did not specify if the diagnosis was AION or PION. We also identified 933 case reports of central retinal artery occlusion (CRAO), 33 cases of pituitary apoplexy, and 245 cases of cortical blindness following nonocular surgery. The incidence of POVL following ocular surgery appears to be much lower than that seen following nonocular surgery. We identified five cases in the literature of direct optic nerve trauma, 47 cases of AION, and five cases of PION following ocular surgery. The specific pathogenesis and risk factors underlying these neuro-ophthalmic complications remain unknown, and physicians should be alert to the potential for loss of vision in the postoperative period.
PMCID: PMC2893763  PMID: 20596508
perioperative; postoperative; vision loss; ocular surgery; nonocular surgery
5.  Ischemic Optic Neuropathy Following Spine Surgery 
Perioperative visual loss (POVL) is a devastating injury that has been reported infrequently after nonocular surgery. The most common cause of POVL is ischemic optic neuropathy (ION). Increasing numbers of cases of ION are being reported after spine surgery, but the etiology of postoperative ION remains poorly understood. After a MEDLINE search of the literature, we reviewed published case reports of ION, specifically those reported after spine surgery performed with the patient in the prone position. Most of the cases involved posterior ION (PION, n = 17), and the remainder anterior (AION, n = 5). Most patients had no or few preoperative vascular disease risk factors. All except one PION and 2 of 5 AION cases reported symptom onset within the first 24 hours after surgery. Visual loss was frequently bilateral (40% of AION, 47% of PION cases). Mean operative time exceeded 450 minutes. The lowest average intraoperative mean arterial blood pressure was 64 mm Hg and the mean lowest intraoperative hematocrit was 27%. The average blood loss was 1.7 L for AION and 5 L for PION patients. PION patients received an average of 8 L of crystalloid solution and 2.2 L of colloid intraoperatively. This compilation of case reports suggests that a combination of prolonged surgery in the prone position, decreased ocular perfusion pressure, blood loss and anemia/hemodilution, and infusion of large quantities of intravenous fluids are some of the potential factors involved in the etiology of postoperative ION. However, levels of blood pressure and anemia intraoperatively were frequently at levels considered acceptable in anesthesia practice. The etiology of postoperative ION remains incompletely understood. Potential strategies to avoid this complication are discussed.
PMCID: PMC2699455  PMID: 15632541
ischemic optic neuropathy; optic nerve; spine surgery; visual loss
6.  A case report and brief review of the literature on bilateral retinal infarction following cardiopulmonary bypass for coronary artery bypass grafting 
Postoperative visual loss is a devastating perioperative complication. The commonest aetiologies are anterior ischaemic optic neuropathy (AION), posterior ischaemic optic neuropathy (PION), and central retinal artery occlusion (CRAO). These appear to be related to certain types of operation, most commonly spinal and cardiac bypass procedures; with the rest divided between: major trauma causing excessive blood loss; head/neck and nasal or sinus surgery; major vascular procedures (aortic aneurysm repair, aorto-bifemoral bypass); general surgery; urology; gynaecology; liposuction; liver transplantation and duration of surgery. The non-surgical risk factors are multifactorial: advanced age, prolonged postoperative anaemia, positioning (supine v prone), alteration of venous drainage of the retina, hypertension, smoking, atherosclerosis, hyperlipidaemia, diabetes, hypercoagulability, hypotension, blood loss and large volume resuscitation. Other important cardiac causes are septic emboli from bacterial endocarditis and emboli caused by atrial myxomata. The majority of AION cases occur during CPB followed by head/neck surgery and prone spine surgery. CPB is used to allow coronary artery bypass grafting on a motionless heart. It has many side-effects and complications associated with its use and we report here a case of bilateral retinal infarction during routine coronary artery bypass grafting in a young male patient with multiple risk factors for developing this complication despite steps to minimise its occurrence.
PMCID: PMC3253690  PMID: 22104114
7.  Anterior ischemic optic neuropathy after conventional coronary artery bypass graft surgery 
Perioperative optic neuropathy is a disease which can lead to serious, irreversible damage of vision. This complication could be the result of non-ocular surgery, for example, cardiac or spinal procedures.
We present a case of anterior ischemic neuropathy (AION) which occurred following a conventional coronary artery bypass graft procedure.
Case Report
A 57-year-old man, 4 days after Conventional Coronary Artery Bypass Graft surgery as result of multi-vessel stabile coronary artery disease and history of anterolateral wall myocardial infarction, was admitted to the Eye Clinic due to significant loss of vision in his right eye. The patient had hypertension and was a heavy smoker. On admission, the slit lamp examination revealed a relative afferent pupillary defect in the right eye. The fundus examination showed optic disc edema with the presence of flame hemorrhages. Best corrected visual acuity (BCVA) was 0.02. The results of eye examination and fluorescein angiography confirmed the diagnosis of AION. Anti-aggregation and antithrombotic treatment was continued with steroids and vasodilators. After 7 days of this treatment we noticed the improvement of BCVA to 0.2. At 6-month follow-up, the vision was stable, and fundus examination revealed optic disc atrophy.
After cardiac surgical operations, such as coronary artery bypass graft procedures, anterior ischemic optic neuropathy may occur. In those cases, close cooperation between the various specialists is necessary.
PMCID: PMC3539541  PMID: 21629193
coronary artery bypass graft; off-pump coronary artery bypass; perioperative ischemic neuropathy; anterior ischemic optic neuropathy
8.  Amaurosis after spine surgery: survey of the literature and discussion of one case 
European Spine Journal  2010;20(2):171-176.
Postoperative vision loss (POVL) associated with spine surgery is a well known, albeit very rare complication. POVL incidence after spinal surgery ranges from 0.028 to 0.2%; however, due to the increase in number and duration of annual complex spinal operations, the incidence may increase. Origin and pathogenesis of POVL remain frequently unknown. A 73-year-old patient presented with lumbar disc herniation with associated neurological deficits after conservative pre-treatment at a peripheral hospital. Known comorbidities included arterial hypertension, moderate arterial sclerosis, diabetes mellitus type 2, mildly elevated blood lipids and treated prostate gland cancer. During lumbar spine surgery in modified prone position the patient presented with an acute episode of severe hypotension, which required treatment with catecholamines and Trendelenburg positioning. Three hours postoperatively, a visual loss in the right eye occurred, resulting in a complete amaurosis. Antihypertensive medication, arteriosclerosis and intraoperative hypotension are possible causes for the POVL. Intraoperative administration of catecholamines and Trendelenburg positioning for treatment of systemic hypotension might further compromise ocular perfusion. In patients with comorbidities compromising arterial blood pressure, blood circulation and microcirculation, POVL must be considered as a severe postoperative complication. It is recommended to inform patients about such complications and obtain preoperative informed consent regarding POVL. Any recent modification of antihypertensive medication must be reported and analysed for potential intraoperative hemodynamic consequences, prior to spine surgery in prone position.
PMCID: PMC3030706  PMID: 20809093
Amaurosis; Blood pressure; Spinal surgery; Prone position; Postoperative vision loss (POVL)
9.  Perioperative visual loss with non-ocular surgery: Case report and review of literature 
Indian Journal of Ophthalmology  2014;62(4):503-505.
Perioperative visual loss (POVL), a rare but devastating complication, has been reported after spine, cardiac, and head-neck surgeries. The various causes include ischemic optic neuropathy, central or branch retinal artery occlusion, and cortical blindness. The contributory factors described are microvascular diseases and intraoperative hemodynamic compromise. However, the exact association of these factors with post-operative blindness has not yet been confirmed. A case of POVL with caesarian section surgery is being presented. The visual loss occurred due to a combined occlusion of central retinal artery and vein. The causes, presentation, and risk factors of POVL after non-ocular surgery are being discussed.
PMCID: PMC4064236  PMID: 24008804
Caesarian section; combined occlusion; non-ocular surgery; perioperative visual loss
10.  Perioperative visual loss: what do we know, what can we do? 
BJA: British Journal of Anaesthesia  2009;103(Suppl 1):i31-i40.
Perioperative visual loss (POVL), a rare, but devastating complication, can follow non-ocular surgery. Highest rates of visual loss are with cardiac and spine surgery. The main causes of visual loss after non-ocular surgery are retinal vascular occlusion and ischaemic optic neuropathy. This review updates readers on the incidence, suspected risk factors, diagnosis, and treatment of POVL due to these conditions.
PMCID: PMC2791856  PMID: 20007988
complications, neurological; complications, neuropathy; eye, intraocular pressure; eye, pupil; surgery, spinal
11.  Temporary postoperative visual loss associated with intracerebral hemorrhage after laparoscopic appendectomy: a case report 
Korean Journal of Anesthesiology  2014;67(3):221-224.
Postoperative visual loss (POVL) after non-ophthalmic surgery is rare, with a reported incidence ranging from 0.013 to 0.2%. Most perioperative visual loss is associated with spine operations and cardiac bypass procedures. The most common cause of POVL is ischemic optic neuropathy. However, there are no previous reports of postoperative visual loss after laparoscopic appendectomy. A 43-year-old female with no underlying disease underwent laparoscopic appendectomy; the operation was completed in one hour and her blood pressure was stable during the perioperative period. In the post-anesthetic care unit, the patient complained of nausea and headache, but she did not complain of any unusual visual symptoms. Approximately one hour after arriving at the ward, the patient complained of visual disturbance. Neurologic examination revealed left homonymous hemianopsia, and subarachnoid hemorrhage and intracerebral hemorrhage were found in the occipital area on brain MRI.
PMCID: PMC4188771  PMID: 25302101
Complications; Laparoscopic appendectomy; Postoperative visual loss
12.  Bilateral ischemic optic neuropathy after transurethral prostatic resection: a case report 
BMC Ophthalmology  2006;6:32.
Nonarteritic ischemic optic neuropathy affects the anterior portion of the optic nerve and is characterized by sudden, painless visual loss. The affected eye has a relative afferent pupillary defect. The typical funduscopic appearance includes optic disc edema, with associated nerve fiber layer hemorrhage. Risk factors include advanced age, systemic hypertension, nocturnal hypotension, diabetes mellitus, and a small cup-to-disc ratio. Bilateral presentation is rare. Postoperative optic neuropathy has been associated with nonocular surgery; risk factors include a combination of prolonged surgical times, acute systemic hypotension, anemia due to blood loss, or prone positioning. We report for the first time a patient with bilateral, simultaneous anterior ischemic optic neuropathy after elective transurethral prostatic resection.
Case presentation
A 66-year old man underwent surgery for benign prostatic hyperplasia. The preoperative blood pressure was 140/85 mmHg, hemoglobin 15.9 g/dL, and hematocrit 48.6%. Two hours postoperatively, the blood pressure, hemoglobin, and hematocrit dropped dramatically. One day later, transient horizontal diplopia developed. Funduscopy showed a congenitally small cup-to-disc ratio without papillary edema. Other ocular findings were unremarkable. By 4 days postoperatively, sudden and painless amaurosis bilaterally developed when the patient awoke with nausea and vomiting. Visual acuity was no light perception bilaterally. The optic discs were swollen with small hemorrhages. Scans of the head and orbits and electrolyte levels were normal. There were no responses on visual evoked potentials bilaterally. The blood pressure was 90/50 mm Hg, the hemoglobin 7.0 g/dL, and the hematocrit 22.9%, necessitating infusion of three units of packed red blood cells. The blood pressure, hematocrit, and hemoglobin increased to normal levels. Three months later the visual acuity remained no light perception. The pupils were unreactive and there was marked optic disc atrophy bilaterally.
Bilateral and simultaneous acute ischemic optic neuropathy may be a rare but devastating surgical complication. The combination of anemia and hypotension may increase the risk of anterior ischemic optic neuropathy postoperatively after transurethral prostatic resection.
PMCID: PMC1624848  PMID: 17034630
13.  Transient bilateral post-operative visual loss in spinal surgery 
European Spine Journal  2011;21(Suppl 4):495-498.
Post-operative visual loss (POVL) following spinal surgery is a rare but devastating complication. Although a number of intra-operative and post-operative factors have been implicated, the exact etiology may still remain unclear.
To report a unique case of transient bilateral POVL in a patient who had undergone lumbar surgery in the prone position.
Study design/setting
This patient was followed up prospectively for 1 year.
Prospective follow-up of a single patient following spinal surgery, who developed transient bilateral POVL.
This patient’s visual loss improved within 48 h.
This is the only documented case of POVL to have resolved completely within 48 h.
PMCID: PMC3369061  PMID: 22170448
Post-operative; Visual loss; Spinal surgery
14.  Human Erythropoietin Effect in Postoperative Visual Loss Following Spine Surgery: A Case Report 
Postoperative visual loss (POVL) has become the focus of attention for anesthesiologists as a hallmark of perioperative management in spine surgery. A number of Intraoperative and postoperative factors has been documented but the exact etiology is still unclear. Nowadays, perioperative management and also complete curing of POLV is a big question of ophthalmologists and anesthesiologists. The purpose of this case report is to present a unique experience of complete curing the POLV.
Case Presentation:
Our patient was a 61-year-old man, with 75 kg weight and 180 cm height. The patient had no history of visual impairment except mild cataract in his right eye. The patient had a history of diffuse idiopathic skeletal hyperostosis (DISH). The patient had undergone lumbar surgery in prone position. The operation time was about 6 hours. About 30 minutes after transferring to postanesthesia care unit (PACU), patient was awake and complained of losing his eyesight. There was no vision and light perception in his right eye on primary examination. Urgent ophthalmologist consultation was requested. In ophthalmology examinations, the pupil reflex to light was absent in the right eye. After obtaining patients and his family informed consent, four hours after the operation, 40000 I.U. of recombinant human erythropoietin (rhEPO) was administered for patient in PACU (IV infusion, in 30 min). An ophthalmologist visited him every 6 hours after administration of rhEPO. The patient was transferred to intensive care unit (ICU) one hour later with total visual loss in the right eye. Ophthalmologic examination after the second dose of rhEPO, 30 hours after the operation, reported pupil reflex enhancement and light perception in his right eye. Finally the third dose of rhEPO (40000 I.U., IV infusion) was administered on the third day. Ophthalmologic examination after the third dose of rhEPO, 60 hours after the operation, reported normal pupillary light reflex of the right eye and visual acuity improvement to 20/20. The patient was discharged from hospital after six days, with normal visual acuity and without any new complications except surgical site pain.
Our case report showed the therapeutic effect of rhEPO in complete curing of POVL. Regarding the side effects of EPO such as thrombogenic effects or mild hemodynamic changes like transient sinus tachycardia during infusion, it seems that beneficial effects of EPO is more than its disadvantages and expenses, for patients with POVL.
PMCID: PMC3997951  PMID: 24790903
Complications; Optic Neuropathy, Ischemic; Postoperative Period; Postoperative; Spinal Cord Ischemia; Vision Disorders
15.  Effects of on- and off-pump coronary artery surgery on graft patency, survival, and health-related quality of life: Long-term follow-up of 2 randomized controlled trials 
Off-pump coronary artery bypass grafting reduces postoperative morbidity and uses fewer resources than conventional surgical intervention with cardiopulmonary bypass. However, only 15% to 20% of coronary artery bypass grafting operations use off-pump coronary artery bypass. One reason for not using off-pump coronary artery bypass might be the surgeon's concern about the long-term patency of grafts performed with this technique. Therefore our objective was to compare long-term outcomes in patients randomized to off-pump coronary artery bypass or coronary artery bypass grafting with cardiopulmonary bypass.
Participants in 2 randomized trials comparing off-pump coronary artery bypass and coronary artery bypass grafting with cardiopulmonary bypass were followed up for 6 to 8 years after surgical intervention to assess graft patency, major adverse cardiac-related events, and health-related quality of life. Patency was assessed by using multidetector computed tomographic coronary angiographic analysis with a 16-slice scanner. Two blinded observers classified proximal, body, and distal segments of each graft as occluded or not. Major adverse cardiac-related events and health-related quality of life were obtained from questionnaires given to participants and family practitioners.
Patency was studied in 199 and health-related quality of life was studied in 299 of 349 survivors. There was no evidence of attrition bias. The likelihood of graft occlusion was no different between off-pump coronary artery bypass (10.6%) and coronary artery bypass grafting with cardiopulmonary bypass (11.0%) groups (odds ratio, 1.00; 95% confidence interval, 0.55–1.81; P>.99). Graft occlusion was more likely at the distal than the proximal anastomosis (odds ratio, 1.11; 95% confidence interval, 1.02–1.20). There were also no differences between the off-pump coronary artery bypass and coronary artery bypass grafting with cardiopulmonary bypass groups in the hazard of death (hazard ratio, 1.24; 95% confidence interval, 0.72–2.15) or major adverse cardiac-related events or death (hazard ratio, 0.84; 95% confidence interval, 0.58–1.24), or mean health-related quality of life across a range of domains and instruments.
Long-term health outcomes with off-pump coronary artery bypass are similar to those with coronary artery bypass grafting with cardiopulmonary bypass when both operations are performed by experienced surgeons.
PMCID: PMC2836483  PMID: 19185140
16.  A surgical approach to coexistent coronary and carotid artery disease. 
Heart  1997;77(2):164-167.
OBJECTIVE: To assess the early results of combined coronary artery bypass graft surgery and carotid endarterectomy. DESIGN: Retrospective and ongoing analysis of patients who underwent combined coronary artery bypass graft surgery and carotid endarterectomy. SETTING: Cardiothoracic unit in a London teaching hospital. PATIENTS: From June 1987 to March 1995, 64 patients were identified. They were patients who were scheduled to have coronary artery bypass graft surgery or required urgent coronary revascularisation and who were found to have significant coexistent carotid disease. (Unilateral carotid stenosis > 70%, bilateral carotid stenosis > 50%, or unilateral carotid stenosis > 50% with contralateral occlusion.) INTERVENTIONS: Both procedures were performed during one anaesthesia: the carotid endarterectomy was performed first without cardiopulmonary bypass. After completion of carotid endarterectomy, coronary artery bypass graft surgery was performed. MAIN OUTCOME MEASURES: The incidence of stroke, transient ischaemic attack, and myocardial infarction in the early postoperative period was analysed. RESULTS: Myocardial revascularisation was successful in all 64 patients. There were no perioperative infarcts. In three patients (4.7%) a new neurological deficit developed postoperatively: two recovered fully before hospital discharge. CONCLUSIONS: Combined coronary artery bypass graft surgery and carotid endarterectomy were performed safely and with good results.
PMCID: PMC484667  PMID: 9068401
17.  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
18.  Patients' Perspective on Full Disclosure and Informed Consent Regarding Postoperative Visual Loss Associated With Spinal Surgery in the Prone Position 
Mayo Clinic Proceedings  2011;86(9):865-868.
OBJECTIVE: To determine patients' opinions regarding the person, method, and timing for disclosure of postoperative visual loss (POVL) associated with high-risk surgery.
PATIENTS AND METHODS: On the basis of findings of a pilot study involving 219 patients at Mayo Clinic in Florida, we hypothesized that at least 80% of patients would prefer disclosure of POVL by the surgeon, during a face-to-face discussion, before the day of scheduled surgery. To test the hypothesis, we sent a questionnaire to 437 patients who underwent prolonged prone spinal surgical procedures at Mayo Clinic in Rochester, MN, or Mayo Clinic in Arizona from December 1, 2008, to December 31, 2009.
RESULTS: Among the 184 respondents, 158 patients gave responses supporting the hypothesis vs 26 with at least 1 response not supporting it, for an observed incidence of 86%. The 2-sided 95% confidence interval is 80% to 91%.
CONCLUSION: At least 80% of patients prefer full disclosure of the risk of POVL, by the surgeon, during a face-to-face discussion before the day of scheduled surgery. This finding supports development of a national patient-driven guideline for disclosing the risk of POVL before prone spinal surgery.
PMCID: PMC3258003  PMID: 21878598
19.  Intravascular Ultrasound to Guide Percutaneous Coronary Interventions 
Executive Summary
The objective of this health technology policy assessment was to determine the effectiveness and cost-effectiveness of using intravascular ultrasound (IVUS) as an adjunctive imaging tool to coronary angiography for guiding percutaneous coronary interventions.
Intravascular Ultrasound
Intravascular ultrasound is a procedure that uses high frequency sound waves to acquire 3-dimensional images from the lumen of a blood vessel. The equipment for performing IVUS consists of a percutaneous transducer catheter and a console for reconstructing images. IVUS has been used to study the structure of the arterial wall and nature of atherosclerotic plaques, and obtain measurements of the vessel lumen. Its role in guiding stent placement is also being investigated. IVUS is presently not an insured health service in Ontario.
Clinical Need
Coronary artery disease accounts for approximately 55% of cardiovascular deaths, the leading cause of death in Canada. In Ontario, the annual mortality rate due to ischemic heart disease was 141.8 per 100,000 population between 1995 and 1997. Percutaneous coronary intervention (PCI), a less invasive approach to treating coronary artery disease, is used more frequently than coronary bypass surgery in Ontario. The number of percutaneous coronary intervention procedures funded by the Ontario Ministry of Health and Long-term Care is expected to increase from approximately 17, 780 in 2004/2005 to 22,355 in 2006/2007 (an increase of 26%), with about 95% requiring the placement of one or more stents. Restenosis following percutaneous coronary interventions involving bare metal stents occurs in 15% to 30% of the cases, mainly because of smooth muscle proliferation and migration, and production of extracellular matrix. In-stent restenosis has been linked to suboptimal stent expansion and inadequate lesion coverage, while stent thrombosis has been attributed to incomplete stent-to-vessel wall apposition. Since coronary angiography (the imaging tool used to guide stent placement) has been shown to be inaccurate in assessing optimal stent placement, and IVUS can provide better views of the vessel lumen, the clinical utility of IVUS as an imaging tool adjunctive to coronary angiography in coronary intervention procedures has been explored in clinical studies.
A systematic review was conducted to answer the following questions:
What are the procedure-related complications associated with IVUS?
Does IVUS used in conjunction with angiography to guide percutaneous interventions improve patient outcomes compared to angiographic guidance without IVUS?
Who would benefit most in terms of clinical outcomes from the use of IVUS adjunctive to coronary angiography in guiding PCIs?
What is the effectiveness of IVUS guidance in the context of drug-eluting stents?
What is the cost-effectiveness ratio and budget impact of adjunctive IVUS in PCIs in Ontario?
A systematic search of databases OVID MEDLINE, EMBASE, MEDLINE In-Process & Other Non-Indexed Citations, The Cochrane Library, and the International Agency for Health Technology Assessment (INAHTA) database for the period beginning in May 2001 until the day of the search, November 4, 2005 yielded 2 systematic reviews, 1 meta-analysis, 6 randomized controlled trials, and 2 non-randomized studies on left main coronary arteries. The quality of the studies ranged from moderate to high. These reports were combined with reports from a previous systematic review for analysis. In addition to qualitative synthesis, pooled analyses of data from randomized controlled studies using a random effect model in the Cochrane Review Manager 4.2 software were conducted when possible.
Findings of Literature Review & Analysis
Intravascular ultrasound appears to be a safe tool when used in coronary interventions. Periprocedural complications associated with the use of IVUS in coronary interventions ranged from 0.5% in the largest study to 4%. Coronary rupture was reported in 1 study (1/54). Other complications included prolonged spasms of the artery after stenting, dissection, and femoral aneurysm.
Based on pooled analyses of data from randomized controlled studies, the use of intravascular ultrasound adjunctive to coronary intervention in percutaneous coronary interventions using bare metal stents yielded the following findings:
For lesions predominantly at low risk of restenosis:
There were no significant differences in preintervention angiographic minimal lumen diameter between the IVUS-guided and angiography-guided groups.
IVUS guidance resulted in a significantly larger mean postintervention angiographic minimal lumen diameter (weighted mean difference of 0.11 mm, P = .0003) compared to angiographic guidance alone.
The benefit in angiographic minimal lumen diameter from IVUS guidance was not maintained at 6-month follow-up, when no significant difference in angiographic minimal lumen diameter could be detected between the two arms (weighted mean difference 0.08, P = .13).
There were no statistically significant differences in angiographic binary restenosis rates between IVUS-guidance and no IVUS guidance (Odds ratio [OR] 0.87 in favour of IVUS, 95% Confidence Interval [CI] [0.64–1.18], P = 0.37).
IVUS guidance resulted in a reduction in the odds of target lesion revascularization (repeat percutaneous coronary intervention or coronary bypass graft) compared to angiographic guidance alone. The reduction was statistically significant at a follow-up period of 6 months to 1 year, and at a follow-up period of 18 month to 2 years (OR 0.52 in favour of IVUS, 95% CI [0.33–0.81], P = .004).
Total revascularization rate (either target lesion or target vessel revascularization) was significantly lower for IVUS-guided patients at 18 months to 2.5 years after intervention (OR 0.43 in favour of IVUS, 95% CI [0.29–0.63], p < .0001).
There were no statistically significant differences in the odds of death (OR 1.36 in favour of no IVUS, P =0.65) or myocardial infarction (OR 0.95 in favour of IVUS, P = 0.93) between IVUS-guidance and angiographic guidance alone at up to 2.5 years of follow-up
The odds of having a major cardiac event (defined as death, myocardial infarction, and target lesion or target vessel revascularization) were significantly lower for patients with IVUS guidance compared to angiographic guidance alone during follow-up periods of up to 2.5 years (OR 0.53, 95% CI [0.36–0.78], P = 0.001). Since there were no significant reductions in the odds of death or myocardial infarction, the reduction in the odds of combined events reflected mainly the reduction in revascularization rates.
For lesions at High Risk of Restenosis:
There is evidence from one small, randomized controlled trial (n=150) that IVUS-guided percutaneous coronary intervention in long de novo lesions (>20 mm) of native coronary arteries resulted in statistically significant larger minimal lumen Diameter, and statistically significant lower 6-month angiographic binary restenosis rate. Target vessel revascularization rate and the rate of combined events were also significantly reduced at 12 months.
A small subgroup analysis of a randomized controlled trial reported no benefit in clinical or angiographic outcomes for IVUS-guided percutaneous coronary interventions in patients with diabetes compared to those guided by angiography. However, due to the nature and size of the analysis, no firm conclusions could be reached.
Based on 2 small, prospective, non-randomized controlled studies, IVUS guidance in percutaneous coronary interventions of left main coronary lesions using bare metal stents or drug-eluting stents did not result in any benefits in angiographic or clinical outcomes. These findings need to be confirmed.
Interventions Using Drug-Eluting Stents
There is presently no evidence on whether the addition of IVUS guidance during the implantation of drug-eluting stents would reduce incomplete stent apposition, or improve the angiographic or clinical outcomes of patients.
Ontario-Based Economic Analysis
Cost-effectiveness analysis showed that PCIs using IVUS guidance would likely be less costly and more effective than PCIs without IVUS guidance. The upfront cost of adjunctive use of IVUS in PCIs ranged from $1.56 million at 6% uptake to $13.04 million at 50% uptake. Taking into consideration cost avoidance from reduction in revascularization associated with the use of IVUS, a net saving of $0.63 million to $5.2 million is expected. However, since it is uncertain whether the reduction in revascularization rate resulting from the use of IVUS can be generalized to clinical settings in Ontario, further analysis on the budget impact and cost-effectiveness need to be conducted once Ontario-specific revascularization rates are verified.
Factors to be Considered in the Ontario Context
Applicability of Findings to Ontario
The interim analysis of an Ontario field evaluation that compared drug-eluting stents to bare metal stents showed that the revascularization rates in low-risk patients with bare metal stents were much lower in Ontario compared to rates reported in randomized controlled trials (7.2% vs >17 %). Even though IVUS is presently not routinely used in the stenting of low-risk patients in Ontario, the revascularization rates in these patients in Ontario were shown to be lower than those reported for the IVUS groups reported in published studies. Based on this information and previous findings from the Ontario field evaluation on stenting, it is uncertain whether the reduction in revascularization rates from IVUS guidance can be generalized to Ontario. In light of the above findings, it is advisable to validate the reported benefits of IVUS guidance in percutaneous coronary interventions involving bare metal stents in the Ontario context.
Licensing Status
As of January 16, 2006, Health Canada has licensed 10 intravascular ultrasound imaging systems/catheters for transluminal intervention procedures, most as class 4 medical devices.
Current Funding
IVUS is presently not an insured procedure under the Ontario Health Insurance Plan and there are no professional fees for this procedure. All costs related to the use of IVUS are covered within hospitals’ global budgets. A single use IVUS catheter costs approximately $900CDN and the procedure adds approximately 20 minutes to 30 minutes to a percutaneous coronary intervention procedure.
According to an expert consultant, current use of IVUS in coronary interventions in Ontario is probably limited to high-risk cases such as interventions in long lesions, small vessels, and bifurcated lesions for which images from coronary angiography are indeterminate. It was estimated that IVUS is being used in about 6% of all percutaneous coronary interventions at a large Ontario cardiac centre.
Expert Opinion
IVUS greatly enhances the cardiac interventionists’ ability to visualize and assess high-risk lesions such as long lesions, narrow lesions, and bifurcated lesions that may have indeterminate angiographic images. Information from IVUS in these cases facilitates the choice of the most appropriate approach for the intervention.
The use of adjunctive IVUS in PCIs using bare metal stents in lesions predominantly at low risk for restenosis had no significant impact on survival, myocardial infarction, or angiographic restenosis rates up to 2.5 years after intervention.
The use of IVUS adjunctive to coronary angiography in percutaneous coronary interventions using bare metal stents in lesions predominantly at low risk for restenosis significantly reduced the target lesion and target vessel revascularization at a follow-up period of 18 months to 2.5 years.
One small study suggests that adjunctive IVUS in PCIs using bare metal stents in long lesions (>20 mm) significantly improved the 6-month angiographic restenosis rate and one-year target lesion revascularization rate. These results need to be confirmed with large randomized controlled trials.
Based on information from the Ontario field evaluation on stenting, it is uncertain whether the reduction in revascularization rate resulting from the use of IVUS in the placement of bare metal stents can be generalized to clinical settings in Ontario.
There is presently insufficient evidence available to determine the impact of adjunctive IVUS in percutaneous interventions in high-risk lesions (other than long lesions) or in PCIs using drug-eluting stents.
PMCID: PMC3379536  PMID: 23074482
20.  Bilateral anterior ischemic optic neuropathy after bilateral neck dissection 
The risk of visual loss after nonocular surgeries is very low, between 0.2% and 4.5%. According to the American Society of Anesthesiologists, ischemic optic neuropathy has been reported mostly after spinal surgery (54.2%), followed by cardiac surgery and radical neck dissection (13.3%). It may occur in association with some conditions that include systemic hypotension, acute blood loss and hypovolemia.
Case report:
A 46-year-old woman, whose diagnosis was laryngeal squamous cell carcinoma, complained of visual loss in her right eye two days after surgery (laryngectomy with bilateral radical neck dissection and left jugular ligature) and one day later in her left eye. The diagnosis was nonarteritic anterior ischemic optic neuropathy.
Anterior ischemic optic neuropathy related to nonocular surgery is usually bilateral and its prognosis is very poor, resulting in blindness or severe visual loss. Although rare, patients should be warned about this complication, which has a profound impact on quality of life, since no therapeutic measure, including correction of hypotension and anemia, seems to improve the prognosis of this complication.
PMCID: PMC2835530  PMID: 20234774
ischemic optic neuropathy; visual loss; radical neck dissection; blood loss
21.  Arterial bypass grafting of the coronary circulation 
Surgical coronary bypass has evolved continually, and recent developments favor performing coronary grafts with all-arterial conduits in order to obtain better long-term graft patencies. With bilateral internal mammary artery grafts and both radial arteries, four excellent arterial conduits exist for revascularization of the majority of multivessel disease patients, including those with valve disorders.
Using contemporary surgical techniques, it is possible to obtain greater than 95% overall long-term graft patencies that translate into better outcomes, including improved survival, freedom from myocardial infarction, percutaneous coronary intervention , and redo coronary bypass.
Two-thirds of patients receive a right internal mammary artery to the left anterior descending , a left internal mammary artery to the circumflex coronary artery system, and a radial artery to the right coronary artery Using newer management techniques, early postoperative complications, including the incidence of sternal infections, are extremely uncommon, and all-arterial grafts currently are used in over 75% of multivessel patients including those with concomitant valve disease. Because patencies and outcomes are so much better than with standard coronary bypass or percutaneous coronary intervention, referring physicians frequently favor all-arterial bypass as the primary therapy for patients with prognostically serious multivessel obstruction. Thus, all-arterial bypass could play an increasingly important role in the future treatment of severe coronary atherosclerosis.
PMCID: PMC3563437  PMID: 23439991
coronary artery bypass; IMA grafts; coronary artery disease; graft patency; outcome analysis
22.  Bilateral internal thoracic artery grafting 
Annals of Cardiothoracic Surgery  2013;2(4):485-492.
The effectiveness of the left internal mammary artery graft to the anterior descending coronary artery as a surgical strategy has been shown to improve the survival rate and decrease the risk of adverse cardiac events in patients undergoing coronary bypass surgery. These clinical benefits appear to be related to the superior short and long-term patency rates of the internal thoracic artery graft. Although the advantages of using of both internal thoracic arteries (ITA) for bypass grafting have taken longer to prove, recent results from multiple data sets now support these findings. The major advantage of bilateral ITA grafting appears to be improved survival rate, while the disadvantages of complex ITA grafting include the increased complexity of operation, and an increased risk of wound complications. While these short-term disadvantages have been mitigated in contemporary surgical practice, they have not eliminated. Bilateral ITA grafting should be considered the procedure of choice for patients undergoing coronary bypass surgery that have a predicted survival rate of longer than ten years.
PMCID: PMC3741891  PMID: 23977627
Coronary bypass surgery; bilateral internal thoracic artery grafting
23.  Is off-pump coronary artery bypass grafting superior to conventional bypass in octogenarians? 
Selected patients appear to benefit from off-pump coronary artery bypass compared with conventional coronary artery bypass with cardiopulmonary bypass. It is unknown whether elderly patients undergoing isolated coronary artery bypass grafting operations derive any benefit when performed off-pump. We hypothesized that off-pump coronary bypass offers a greater operative benefit to elderly patients when compared with conventional coronary artery bypass.
A total of 1993 elderly patients (age ≥80 years) underwent isolated, primary coronary artery bypass graft operations at 16 different statewide centers from 2003 to 2008. Patients were stratified into 2 groups: conventional coronary artery bypass (n = 1589, age = 82.5 ± 2.4 years) and off-pump bypass (n = 404, age = 83.0 ± 2.4 years). Preoperative risk, intraoperative findings, postoperative complications, and costs were evaluated.
Patients undergoing off-pump bypass grafting were marginally older (P = .001) and had higher rates of preoperative atrial fibrillation (14.6%vs 10.0%; P = .01) and New York Heart Association class IV heart failure (29.7% vs 21.1%; P <.001) than did those having conventional coronary bypass grafting. Other patient risk factors and operative variables, including Society of Thoracic Surgeons predicted risk of mortality, were similar in both groups (P = .15). Compared with off-pump bypass, conventional coronary bypass incurred higher blood transfusion rates (2.0 ± 1.7 units vs 1.6 ± 1.9 units; P = .05) as well as more postoperative atrial fibrillation (28.4% vs 21.5%; P = .003), prolonged ventilation (14.7% vs 11.4%; P = .05), and major complications (20.1% vs 15.6%; P = .04). Importantly, postoperative stroke (2.6% vs 1.7%; P = .21), renal failure (8.1% vs 6.2%; P = .12), and postoperative length of stay (P = .41) were no different between groups. Despite more complications in patients having conventional bypass, operative mortality (P = .53) and hospital costs (P = .43) were similar to those of patients having off-pump procedures.
Performance of coronary artery bypass grafting among octogenarian patients is safe and effective. Off-pump coronary artery bypass confers shorter postoperative ventilation but equivalent mortality to conventional coronary artery bypass. Off-pump coronary artery bypass was associated with a reduction in the composite incidence of major complications in unadjusted and adjusted analyses and should be considered an acceptable alternative to conventional bypass for myocardial revascularization in elderly patients.
PMCID: PMC3071621  PMID: 21051050
24.  Vision Loss After Spinal Fusion for Scoliosis in a Child With Spinal Cord Injury 
Vision loss after spinal surgery is a rare and devastating complication. Risk factors include patient age, operative time, estimated blood loss, and intraoperative fluid management. Children with spinal cord injury often develop scoliosis that requires surgical correction.
Study Design:
Case report.
Clinical and radiographic review was conducted of a 15-year-old boy who developed severe scoliosis after sustaining a C5 level injury at age 4 years from a motor vehicle crash.
The patient underwent a posterior spinal fusion from T2 to the pelvis, and good correction of the spinal deformity was attained. During the 8-hour procedure, blood loss was 4,000 mL (approximately 1.2 blood volumes) and 17,000 mL of fluids were administered. On postoperative day 5, it was determined that the patient had complete visual loss. Neuro-ophthalmology consultation confirmed the diagnosis of posterior ischemic optic neuropathy.
A significant number of children with spinal cord injury develop scoliosis requiring surgical correction. These procedures are often lengthy, with the potential for extensive blood loss and fluid shifts, factors that may increase the likelihood of postoperative vision loss. Patients should be counseled about this complication, and the surgical and anesthesiology teams should take all measures to minimize its occurrence.
PMCID: PMC2792468  PMID: 20025158
Blindness; Scoliosis; Spinal cord injuries; Spinal fusion; Neuropathy, optic, ischemic, posterior
25.  Impact of remote ischemic preconditioning preceding coronary artery bypass grafting on inducing neuroprotection (RIPCAGE): study protocol for a randomized controlled trial 
Trials  2014;15(1):414.
Neurological complications after cardiac surgery have a profound impact on postoperative survival and quality of life. The increasing importance of strategies designed to improve neurological outcomes mirrors the growing risk burden of the contemporary cardiac surgical population. Remote ischemic preconditioning (RIPC) reduces adverse sequelae of ischemia in vulnerable organs by subjecting tissues with high ischemic tolerance to brief periods of hypoperfusion. This trial will evaluate the neuroprotective effect of RIPC in the cardiac surgical arena, by employing magnetic resonance imaging (MRI) and neurocognitive testing.
Patients scheduled for elective coronary artery bypass grafting with the use of cardiopulmonary bypass will be screened for the study. Eligible patients will be randomized to undergo either a validated RIPC protocol or a sham procedure. The RIPC will be induced by inflation of a blood pressure cuff to 200 mmHg for 5 minutes, followed by a 5-minute reperfusion period. Three sequences of interchanging cuff inflations and deflations will be employed. Neurocognitive testing and MRI imaging will be performed preoperatively and on postoperative day 7. Paired pre- and postoperative neurocognitive and neuroimaging data will then be compared. The primary composite outcome measure will consist of new ischemic lesions on brain MRI, postprocedural impairment in brain connectivity on resting-state functional MRI (rs-fMRI), and significant new declines in neurocognitive performance. The secondary endpoint measures will be the individual components of the primary endpoint measures, expressed as continuous variables, troponin T release on postoperative day 1 and the incidence of major adverse cardiovascular events at 3 months postoperatively. Major adverse cardiovascular events, including accumulating cardiovascular mortality, stroke, nonfatal myocardial infarction, and rehospitalization for ischemia, will form a composite endpoint measure.
This trial will aim to assess whether RIPC in patients subjected to surgical myocardial revascularization employing cardiopulmonary bypass initiates a neuroprotective response. Should the results of this trial indicate that RIPC is effective in reducing the incidence of adverse neurological events in patients undergoing coronary artery bypass grafting, it could impact on the current standard of care.
Trial registration NCT02177981.
PMCID: PMC4223850  PMID: 25348157
coronary artery bypass grafting; functional; magnetic resonance imaging; neurocognitive outcome; remote ischemic preconditioning

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