Carotid endarterectomy for asymptomatic carotid stenosis: a meta-analysis

OBJECTIVE: To assess the value of carotid endarterectomy for prevention of stroke in patients with asymptomatic carotid stenosis. DESIGN: Systematic review and meta-analysis of randomised controlled trials in patients with asymptomatic carotid stenosis in which subjects were allocated to carotid endarterectomy or to medical treatment alone. SUBJECTS: Five trials enrolled 2440 patients with stenosis >/ 50%. MAIN OUTCOME MEASURES: Stroke ipsilateral to the stenosis, all strokes, and perioperative complications (stroke or death). RESULTS: In patients who underwent carotid endarterectomy (n=1215) there was a significant reduction in the odds of ipsilateral stroke plus perioperative stroke or death (odds ratio 0.62; 95% confidence interval 0.44 to 0.86), corresponding to a 2% absolute risk reduction over about 3.1 years. The prevalence of stroke in any location was also reduced (0.68; 0.51 to 0.9) in patients undergoing carotid endarterectomy. During the immediate postoperative period there was an increased prevalence of stroke or death among such patients (4.51; 2.36 to 8.64). CONCLUSION: Carotid endarterectomy in patients with asymptomatic carotid stenosis unequivocally reduces the incidence of ipsilateral stroke, though the absolute benefit is relatively small. Given the modest benefit of surgery for unselected patients with asymptomatic carotid artery stenosis carotid endarterectomy cannot be routinely recommended for these patients pending reliable identification of high risk subgroups, and medical management is a sensible alternative for most patients.     

Dissociative experiences and eating disorders in a female college sample

OBJECTIVES: Perioperative ischaemic stroke is the leading cause of morbidity and mortality associated with carotid endarterectomy (CEA). The aim was to test the hypotheses that the detection of microembolic ultrasonic signals (MES) with transcranial Doppler ultrasound (TCD) during and after the operation may be of value in identifying patients at increased perioperative stroke risk. DESIGN: Open prospective case series. PATIENTS AND METHODS: Eighty-one consecutive patients undergoing CEA with TCD monitoring. Preoperative, intraoperative and interval postoperative TCD monitoring of the middle cerebral artery (MCA) ipsilateral to the operated carotid artery. On-line pre- and intraoperative MES counting and blinded off-line analysis of postoperative MES counts. End-points were any focal neurological deficit and death at 30 days postoperatively. RESULTS: MES were detected in 94% of patients intraoperatively and 71% of cases during the first postoperative hour. MES counts ranged from 0 to 25 per operative phase (range of median counts 0-8) and from 0 to 212 per hour postoperatively (range of median counts 0-4). Eight cases (10%) developed postoperative MES counts greater than 50/h. Five of these eight cases evolved ischaemic neurological deficits in the territory of the insonated MCA, indicating a strong association between frequent postoperative microembolism and the development of early cerebral ischaemia (chi 2 = 34.2, p < 0.0001). Intraoperative MES were not associated with clinical outcome measures. CONCLUSIONS: MES counts of greater than 50/h in the early postoperative phase of carotid endarterectomy are predictive of the development of ipsilateral focal cerebral ischaemia.     

Intraoperative high-dose regional urokinase infusion for cerebrovascular occlusion after carotid endarterectomy

Operative stroke complicating carotid endarterectomy is traditionally treated by reexploration of the operative site to correct a potentially causative lesion; however, attempts are not made to diagnose or treat the intracranial arterial occlusion. A 65-year-old man had a right hemiplegia during a left carotid endarterectomy that was caused by premature reversal of heparin, which resulted in thrombosis of his left anterior cerebral artery. On reexploration, the patient was treated with a 1-hour infusion of 1 million U urokinase through an indwelling carotid shunt. A repeat arteriogram demonstrated patency of the left anterior cerebral artery, with complete clot dissolution and resolution of the right hemiplegia on awakening. Natural history studies of stroke and prospective, angiographically controlled clinical trials of intraarterial thrombolytic therapy for acute stroke support the use of intraoperative intraarterial infusion of urokinase as part of a therapeutic approach to patients who have an ischemic stroke during carotid endarterectomy.     

Impaired dynamic cerebral autoregulation in carotid artery stenosis

BACKGROUND AND PURPOSE: If it could be determined whether cerebral blood flow can be maintained (autoregulated) during transient falls in arterial blood pressure, we might be able to identify patients with carotid stenosis who are at risk of stroke. However, conventional methods of determining autoregulation in such patients are invasive and/or expensive. METHODS: We used a new noninvasive method to estimate dynamic cerebral autoregulation in 27 patients with carotid stenosis and 21 age-matched normal controls. After a stepwise fall in arterial blood pressure, we determined the rate of rise of middle cerebral artery blood flow velocity compared with that of arterial blood pressure. We compared the method with a conventional method of determining cerebral hemodynamics, CO2 reactivity. RESULTS: Autoregulatory index (ARI) was significantly reduced in middle cerebral arteries ipsilateral to a stenosed/ occluded carotid artery: mean +/- SD 3.3 +/- 2.2 compared with normal controls (6.3 +/- 1.1; P < .0001) and nonstenosed carotid arteries in patients (5.9 +/- 2.1; P < .002). A subgroup of patients with severe impairment was identified. ARI returned to normal after carotid endarterectomy was performed. In a number of cases, ARI was impaired in the presence of CO2 reactivity. CONCLUSIONS: This simple technique allows identification of impaired autoregulation in patients with carotid artery disease. It may allow identification of patients at risk from transient falls of blood pressure as may occur at the onset of antihypertensive therapy and during surgery. It may allow a subgroup of patients with asymptomatic carotid stenosis who are at risk of hemodynamic stroke to be identified.     

Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators

BACKGROUND: Previous studies have shown that carotid endarterectomy in patients with symptomatic severe carotid stenosis (defined as stenosis of 70 to 99 percent of the luminal diameter) is beneficial up to two years after the procedure. In this clinical trial, we assessed the benefit of carotid endarterectomy in patients with symptomatic moderate stenosis, defined as stenosis of less than 70 percent. We also studied the durability of the benefit of endarterectomy in patients with severe stenosis over eight years of follow-up. METHODS: Patients who had moderate carotid stenosis and transient ischemic attacks or nondisabling strokes on the same side as the stenosis (ipsilateral) within 180 days before study entry were stratified according to the degree of stenosis (50 to 69 percent or <50 percent) and randomly assigned either to undergo carotid endarterectomy (1108 patients) or to receive medical care alone (1118 patients). The average follow-up was five years, and complete data on outcome events were available for 99.7 percent of the patients. The primary outcome event was any fatal or nonfatal stroke ipsilateral to the stenosis for which the patient underwent randomization. RESULTS: Among patients with stenosis of 50 to 69 percent, the five-year rate of any ipsilateral stroke (failure rate) was 15.7 percent among patients treated surgically and 22.2 percent among those treated medically (P=0.045); to prevent one ipsilateral stroke during the five-year period, 15 patients would have to be treated with carotid endarterectomy. Among patients with less than 50 percent stenosis, the failure rate was not significantly lower in the group treated with endarterectomy (14.9 percent) than in the medically treated group (18.7 percent, P=0.16). Among the patients with severe stenosis who underwent endarterectomy, the 30-day rate of death or disabling ipsilateral stroke persisting at 90 days was 2.1 percent; this rate increased to only 6.7 percent at 8 years. Benefit was greatest among men, patients with recent stroke as the qualifying event, and patients with hemispheric symptoms. CONCLUSIONS: Endarterectomy in patients with symptomatic moderate carotid stenosis of 50 to 69 percent yielded only a moderate reduction in the risk of stroke. Decisions about treatment for patients in this category must take into account recognized risk factors, and exceptional surgical skill is obligatory if carotid endarterectomy is to be performed. Patients with stenosis of less than 50 percent did not benefit from surgery. Patients with severe stenosis (> or =70 percent) had a durable benefit from endarterectomy at eight years of follow-up.     

Symptomatic recurrent carotid stenosis and aneurysmal degeneration after endarterectomy

BACKGROUND: Aneurysmal degeneration of a carotid reconstruction was not recognized until the patient, who was known to have recurrent carotid artery stenosis, had a thromboembolic stroke. This sequelae of carotid endarterectomy is a serious complication, associated with a high morbidity and mortality rate. This review was conducted to establish the risk of transient ischemic attack and stroke for patients found to have recurrent carotid stenosis associated with aneurysmal degeneration of the carotid artery after endarterectomy. METHODS: A case is reported, and 100 literature references of aneurysmal degeneration of the carotid artery after endarterectomy were reviewed. RESULTS: False aneurysm from anastomotic disruption was the most common presentation identified in the cases reviewed. Nineteen of the patients had a significant neurologic event; however, three (50%) of six patients with aneurysm and recurrent carotid artery stenosis had a transient ischemic attack or stroke. CONCLUSIONS: The incidence of neurologic symptoms is markedly increased when recurrent carotid artery stenosis is associated with carotid aneurysm. During postoperative surveillance after endarterectomy, the identification of recurrent carotid artery stenosis requires evaluation for aneurysmal degeneration of the carotid artery with duplex scanning. These patients are at significant risk for transient ischemic attack and stroke. This rare complication merits operative repair.     

Influence of projected complication rates on estimated appropriate use rates for carotid endarterectomy. Appropriateness Project Investigators. Academic Medical Center Consortium

OBJECTIVE: To examine specifically the influence of estimated perioperative mortality and stroke rate on the assessment of appropriateness of carotid endarterectomy. DATA SOURCES/STUDY SETTING: An expert panel convened to rate the appropriateness of a variety of potential indications for carotid endarterectomy based on various rates of perioperative complications. We then applied these ratings to the charts of 1,160 randomly selected patients who had carotid endarterectomy in one of the 12 participating academic medical centers. STUDY DESIGN: An expert panel evaluated indications for carotid endarterectomy using the modified Delphi approach. Charts of patients who received surgery were abstracted, and clinical indications for the procedure as well as perioperative complications were recorded. To examine the impact of surgical risk assessment on the rates of appropriateness, three different definitions of risk strata for combined perioperative death or stroke were used: Definition A, low risk < 3 percent; Definition B, low risk < 5 percent; and Definition C, low risk < 7 percent. PRINCIPAL FINDINGS: Overall hospital-specific mortality ranged from 0 percent to 4.0 percent and major complications, defined as death, stroke, intracranial hemorrhage, or myocardial infarction, varied from 2.0 percent to 11.1 percent. Most patients (72 percent) had surgery for transient ischemic attack or stroke; 24 percent of patients were asymptomatic. Most patients (82 percent) had surgery on the side of a high-grade stenosis (70-99 percent). When the thresholds for operative risk were placed at the values defined by the expert panel (Definition A), only 33.5 percent of 1,160 procedures were classified as "appropriate." When the definition of low risk was shifted upward, the proportion of cases categorized as appropriate increased to 58 percent and 81.5 percent for Definitions B and C, respectively. CONCLUSIONS: Despite the high proportion of procedures performed for symptomatic patients with a high degree of ipsilateral extracranial carotid artery stenosis and generally low rates of surgical complications at the participating institutions, the overall rate of "appropriateness" using a perioperative complication rate of < 3 percent was low. However, the rate of "appropriateness" was extremely sensitive to judgments about a single clinical feature, surgical risk. These data show that before applying such "appropriateness" ratings, it is crucial to perform sensitivity analyses in order to assess the stability of the results. Results that are robust to moderate in variation in surgical risk provide a much sounder basis for policy making than those that are not.     

Role of transcranial Doppler and stump pressure during carotid endarterectomy

BACKGROUND AND PURPOSE: The aim of our study was to clarify the pathophysiology of perioperative cerebral complications during carotid endarterectomy in our series. METHODS: By means of transcranial Doppler ultrasonography and stump pressure measurement, we monitored 112 patients who underwent carotid endarterectomy under general anesthesia for symptomatic or asymptomatic severe carotid stenosis. RESULTS: Of 18 patients who underwent carotid endarterectomy with intra-arterial shunt, 2 (11.1%) developed an ischemic stroke. Of the other 94 patients, one suffered a nucleocapsular hemorrhage and 5 had cerebral ischemic complications. In these 5 patients, the duration of clamping was significantly longer (mean +/- SD, 16.4 +/- 1.1 versus 12.7 +/- 2.6 minutes; P = .0019), and the decrease of middle cerebral artery mean velocity on clamping was significantly greater (mean +/- SD, 56.4 +/- 4.9% versus 28.8 +/- 20.2%; P = .0031), while stump pressure was not significantly different. Microembolic signals were recorded in 70 patients (62.5%) and were not associated with cerebral ischemic complications. The 7 patients who developed cerebral ischemic complications had a significantly higher percentage of stenosis in the contralateral internal carotid artery (mean +/- SD, 82.0 +/- 17.8% versus 29.3 +/- 36.4%; P = .0018). CONCLUSIONS: The results of our study suggest that the major complications of carotid endarterectomy may be due to hemodynamic factors. Stump pressure alone is not a reliable indicator of hemodynamic changes that predict cerebral ischemia. Particulate microembolism may cause more subtle changes in cerebral parenchyma, but further studies are needed to clarify this point.     

In vitro expression of soluble and cell surface-associated CD44 on endometrial cells from women with and without endometriosis

CONTEXT: The relative importance of hemodynamic factors in the pathogenesis and treatment of stroke in patients with carotid artery occlusion remains controversial. OBJECTIVE: To test the hypothesis that stage II cerebral hemodynamic failure (increased oxygen extraction measured by positron emission tomography [PET]) distal to symptomatic carotid artery occlusion is an independent risk factor for subsequent stroke in medically treated patients. DESIGN AND SETTING: Prospective, blinded, longitudinal cohort study of patients referred from a group of regional hospitals between 1992 and 1996. PATIENTS: From 419 subjects referred, 81 with previous stroke or transient ischemic attack in the territory of an occluded carotid artery were enrolled. All were followed up to completion of the study, with average follow-up of 31.5 months. MAIN OUTCOME MEASURES: Telephone contact every 6 months recorded the subsequent occurrence of all stroke, ipsilateral ischemic stroke, and death. RESULTS: Stroke occurred in 12 of 39 patients with stage II hemodynamic failure and in 3 of 42 patients without (P = .005); stroke was ipsilateral in 11 of 39 patients with stage II hemodynamic failure and in 2 of 42 patients without (P = .004). Six deaths occurred in each group (P = .94). The age-adjusted relative risk conferred by stage II hemodynamic failure was 6.0 (95% confidence interval [CI], 1.7-21.6) for all stroke and 7.3 (95% CI, 1.6-33.4) for ipsilateral stroke. CONCLUSIONS: Stage II hemodynamic failure defines a subgroup of patients with symptomatic carotid occlusion who are at high risk for subsequent stroke when treated medically. A randomized trial evaluating surgical revascularization in this high-risk subgroup is warranted.     

Carotid endarterectomy without a shunt for symptomatic lesions associated with contralateral severe stenosis or occlusion

PURPOSE: The purpose of this study was to assess the adequacy of thiopental protection against ischemic cerebral damage in patients undergoing carotid endarterectomy for symptomatic stenosis greater than 70% in association with contralateral stenosis greater than 70% or contralateral occlusion. METHODS: All patients (n=259) with severe bilateral carotid disease who underwent carotid endarterectomy for symptomatic stenosis greater than 70% were extracted from the database of an ongoing prospective carotid surgery study. Large-dose thiopental sodium without shunting was used for cerebral protection during endarterectomy. Asymmetric electroencephalogram changes during the operation, carotid occlusion time, stroke onset, and neuropathologic outcomes were analyzed. RESULTS: Three contralateral strokes occurred in the series, producing a cerebral morbidity/mortality rate of 1.2% (major 0.4%, minor 0.8%). Transient morbidity was 1.9% made of two reversible ischemic neurologic deficits and three transient ischemic attacks. New asymmetric electroencephalography changes were seen in 49 (19% patients, one of whom had transient deficit. Average occlusion time was 35 minutes. All strokes occurred within 24 hours of the procedure. Patients with previous stroke and and systemic hypertension seemed at greatest risk, and the contralateral hemisphere was the area at greatest risk. All transient deficits were ipsilateral and related to technical complications rather failed protection. CONCLUSIONS: Thiopental cerebral protection eliminates strokes caused by complications of shunting, prevents ischemic stroke during carotid occlusion for periods up to 67 minutes (average 35 minutes), allows meticulous management of the operative site, may modify or minimize clinical neurologic deficit, and in our experience has rendered intraluminal shunting obsolete.     

Predicting the effect of carotid artery occlusion during carotid endarterectomy: comparing transcranial doppler measurements and cerebral angiography

BACKGROUND and PURPOSE: We correlated the mean transcranial Doppler blood flow velocity (FVm) during carotid endarterectomy with the functional collateral pathway(s) documented by angiography. METHODS: Three patient groups were established: group 1 was dependent on the anterior communicating artery, group 2 on the anterior communicating artery and ipsilateral posterior communicating artery, and group 3 on the ipsilateral posterior communicating artery. Continuous middle cerebral artery FVm and electroencephalographic monitoring were performed in 45 patients during carotid endarterectomy. RESULTS: Clamped FVm was lowest in group 3 at 17+/-9 cm/s versus 36+/-16 and 33+/-11 cm/s for groups 1 and 2 (P<0.01). FVm values in groups 1 and 2 were similar. There was significant cerebral arterial vasodilation in group 3 patients on the basis of a pulsatility index of 0.38+/-0.15. The maximum FVm after clamp release was similar among the 3 groups. Normalized blood flow velocity 1 minute before release of the clamp was increased from the minimum flow velocity after clamping only in group 1 and 2 patients. CONCLUSIONS: The ipsilateral posterior communicating artery is a minor collateral pathway during acute carotid occlusion that contributes little to the collateral flow if there is a functional anterior communicating artery. Collateral flow through the middle cerebral artery is not recruited during occlusion in group 3 patients. The reperfusion FVm transient is independent of the primary collateral pathway. Documentation of functional collateral pathways on the basis of Doppler or angiographic examination may be advantageous in future studies since it can provide the basis for comparison among studies.     

Comparison of hemodynamic cerebral ischemia and microembolic signals detected during carotid endarterectomy and carotid angioplasty

BACKGROUND AND PURPOSE: There has been concern about carotid percutaneous transluminal angioplasty (PTA) carrying a greater risk of cerebral ischemia than carotid endarterectomy. We set out to compare cerebral hemodynamics and microembolization during carotid PTA and CEA. METHODS: We used transcranial Doppler to monitor the middle cerebral artery of 28 patients undergoing carotid PTA (n = 14) or carotid endarterectomy (CEA) with a shunt (n = 14). Each period during which the internal carotid artery was occluded by PTA balloon or by clamp when the shunt was not in place was timed. Individual periods were summated to give a total occlusion time. Ischemic time was defined as the period for which mean middle cerebral artery velocity fell to a third or less of baseline. Microembolic signals were counted during each procedure. RESULTS: CEA resulted in significantly longer individual and total occlusion time than PTA (mean individual occlusion time, seconds), CEA, 168 +/- 51; PTA, 20 +/- 7; P < .001; mean total occlusion time; CEA, 337 +/- 70; PTA, 26 +/- 10; P < .001. Ischemic time was also significantly longer during CEA than during PTA (CEA, 165 +/- 40; PTA, 17 +/- 5; P = .001). There were significantly more microembolic signals during PTA than during CEA (mean number of microembolic signals during CEA, 52 +/- 64; during PTA, 202 +/- 119; P = .001). There was no correlation between any of the parameters measured and periprocedural stroke, which occurred in one patient in each group. CONCLUSION: PTA results in less hemodynamic ischemia but more cerebral microembolism than CEA. In this small series, however, it is not possible to comment on the relations between ischemic time, microembolism, and stroke.     

Surgical treatment of common carotid artery occlusion

Eight patients with common carotid artery (CCA) occlusion underwent bypass with saphenous vein to either the carotid bifurcation (five), the internal carotid artery (two), or the external carotid artery (one). Indications included ipsilateral transient ischemic attack (two), recent nondisabling hemispheric stroke (two), and transient nonhemispheric cerebral symptoms (two). Two asymptomatic patients with CCA occlusion and contralateral internal carotid stenosis underwent prophylactic revascularization prior to planned aortic surgery. There were no perioperative strokes, occlusions, or deaths. Late ipsilateral stroke occurred in two patients, and one patient had a single transient ischemic attack after 2 years. The four patients with preoperative transient cerebral ischemia experienced relief of their symptoms. Duplex ultrasound is an accurate screening modality for distal patency. Collateral filling of the internal or external carotid artery can usually be demonstrated after aortic arch or retrograde brachial contrast injection. End-to-end distal anastomosis after endarterectomy eliminates the original occlusive plaque as a potential source of emboli. The subclavian artery is preferred for inflow on the left. The CCA origin is easily accessible for inflow on the right. Bypass of the occluded CCA is safe and may be effective in relieving transient cerebral ischemic symptoms, although long-term ipsilateral neurologic sequelae may still occur.     

The Edinburgh Extended Glasgow Outcome Scale (EEGOS): rationale and pilot studies

OBJECTIVES: To determine whether patch angioplasty is more effective than primary closure in carotid endarterectomy, and whether one type of patch is better than another. DESIGN: Systematic review of the randomised trials. MATERIALS: Trials were identified from the Cochrane Stroke Review Group database plus additional handsearching, electronic searching, and personal contact. METHODS: Two authors independently selected studies for inclusion and extracted details of trial quality and data on the following outcomes: any stroke; stroke ipsilateral to the operated artery; death; occlusion or restenosis, and other significant arterial complications. Meta-analysis of odds ratios (OR) was performed using the Peto method. RESULTS: Six trials (882 operations) compared routine patching with primary closure. Routine patching was associated with significant reductions in the risks of ipsilateral stroke during the perioperative period (OR 0.34, 95% CI 0.15-0.76) and during long-term follow-up (OR 0.38, 95% CI 0.16-0.88). Significant reductions in the odds of any stroke, stroke or death, acute arterial occlusion and long-term restenosis were also found. However, these results were based on very small numbers of outcome events and may be biased by losses to follow-up and publication bias. Three trials (326 operations) compared the use of polytetrafluoroethylene patches with venous patches. There were too few events (strokes, deaths, arterial complications) to determine whether there were significant differences between the patch materials. Fewer pseudoaneurysms occurred in those who received synthetic patches but the clinical consequence of this was unclear. CONCLUSIONS: Routine carotid patch angioplasty was associated with promising reductions in the risks of ipsilateral stroke and death, but the results should be interpreted cautiously because of the small number of outcome events, significant losses to follow-up, and poor trial methodology. Ideally, a large definitive trial should be performed. There is insufficient evidence to support the preferential use of one particular type of patch versus another.     

Determinants of outcome after carotid endarterectomy

BACKGROUND: The efficacy of carotid endarterectomy for selected patients has been evaluated with randomized controlled clinical trials. The generalizability of these studies to average surgical practice remains an important public health concern. OBJECTIVE: The objective of the study was to determine the predictors of outcome after carotid endarterectomy on a regional basis. Patients and Methods: The study was designed as a retrospective cohort study and included all consecutive patients presented for carotid endarterectomy at the 8 University of Toronto-affiliated hospitals in the period from January 1, 1994, to December 31, 1996. The main outcome measure was 30-day postoperative stroke or death rate. RESULTS: During the study interval, 1280 primary carotid endarterectomies were performed. The overall combined stroke and death rate was 6.3% for all patients who underwent endarterectomy (4.0% for patients who were asymptomatic). The significant predictors of poor outcome were the following: presenting symptoms (odds ratio, 1.74; 95% confidence interval [CI], 0.96, 3.12), low surgeon volume (<6 cases per year; odds ratio, 3.98; 95% CI, 1.65, 9.58), and left-sided surgery (odds ratio, 1.72; 95% CI, 1.07, 2.76). CONCLUSION: These data suggest that adoption of the recommendations of the symptomatic carotid endarterectomy trials is appropriate. However, endarterectomy for asymptomatic lesions remains of uncertain benefit on a regional basis and must be individualized to the experience of the specific surgeon. The surgeon volume/outcome relationship that is identified in this study suggests a need for a minimum volume threshold for this procedure.     

A dehydroalanyl residue can capture the 5''-deoxyadenosyl radical generated from S-adenosylmethionine by pyruvate formate-lyase-activating enzyme

OBJECTIVE: To analyze the effects of carotid endarterectomy on the retrobulbar circulation of patients with severe occlusive carotid artery disease (OCAD) by means of color Doppler imaging (CDI). DESIGN: Prospective. PARTICIPANTS: A total of 17 consecutive patients with severe OCAD and neurologic symptoms (with a history of transitory ischemic attack or cerebral vascular accident) participated. INTERVENTION: All 17 patients underwent carotid endarterectomy. The CDI of both orbits was performed by one masked investigator before surgery and at 1 week and 1 month after surgery. MAIN OUTCOME MEASURES: Peak systolic velocity, end diastolic velocity, and resistive index of the ophthalmic, central retinal, and temporal short posterior ciliary arteries were measured. The authors compared the hemodynamic parameters at all intervals. RESULTS: Peak systolic and end diastolic velocities in the ophthalmic, central retinal, and temporal short posterior ciliary arteries increased significantly 1 week and 1 month after carotid endarterectomy (P < 0.05). After surgery, the resistive indices in the central retinal and temporal short posterior ciliary arteries decreased significantly at both intervals (P < 0.05). The six patients who had reversed ophthalmic artery flow before surgery showed forward ophthalmic artery flow after carotid endarterectomy. The contralateral orbits showed no significant hemodynamic change after endarterectomy (P < 0.05). CONCLUSIONS: Hemodynamic changes in patients with severe OCAD undergoing carotid endarterectomy suggest improvement in the ipsilateral retrobulbar blood flow.     

Course of cerebrovascular reactivity in patients with carotid artery occlusions

BACKGROUND AND PURPOSE: Patients with internal carotid artery occlusions and highly impaired cerebrovascular reactivity have been identified as having an increased risk of stroke. It is still unclear, however, whether cerebral hemodynamics may be restored in the course of time by the development of collaterals. METHODS: During a 5-year period we assessed cerebrovascular reactivity in 452 carotid occlusions by transcranial Doppler CO2 testing. Ninety-eight patients could be reinvestigated at least once after 2 to 58 months (mean follow-up time, 26 months). RESULTS: On admission, patients with recent transient ischemic attack or stroke (< or = 3 months) as well as patients with contralateral carotid stenoses of 80% diameter reduction or greater and occlusions revealed a significantly higher incidence of impaired CO2 reactivity (P < .0001 and P < .01, respectively). During follow-up, 64% of the patients with no or minor contralateral carotid stenoses, but only 22% of the patients with bilateral carotid occlusions, showed a spontaneous improvement in cerebrovascular reactivity (P < .001), mainly during the first few months. In six of eight patients cerebral hemodynamics on the occluded side improved after endarterectomy of a contralateral high-grade carotid stenosis. Five of the patients who did not undergo surgery developed a stroke during follow-up, with three of them occurring in patients with permanently exhausted cerebrovascular reactivity. CONCLUSIONS: In the majority of patients with carotid occlusions an initially impaired cerebrovascular reactivity improves spontaneously with time. This could influence therapeutic decisions: During the first few months antihypertensive treatment may be avoided in such cases until a reestablished reactivity can be demonstrated. If cerebral hemodynamics remain depleted, extracranial-intracranial bypass surgery or endarterectomy of an asymptomatic contralateral high-grade carotid stenosis could be helpful.     

Risk factors for stroke after cardiac surgery: Buffalo Cardiac-Cerebral Study Group

PURPOSE: The purpose of this study was to identify risk factors for stroke in patients undergoing heart surgery. METHODS: A retrospective chart review of patients who underwent cardiac surgery in three hospitals of the State University of New York at Buffalo system over a 36-month period was completed. Demographics and risk factors were recorded, and stroke and death were determined by chart review. Carotid artery stenosis was determined by duplex examination. Data were analyzed by chi-squared and multiple logistic regression. RESULTS: One thousand one hundred seventy-nine cases were analyzed, with a mortality rate of 2.3%, stroke rate of 1.6%, and combined stroke/death rate of 3.1%. Four variables were found to be associated with an increased risk of stroke: carotid artery stenosis greater than 50%, redo heart surgery, valve surgery, and prior stroke. Five variables were associated with increased mortality rates:; carotid artery stenosis greater than 50%, redo surgery, peripheral vascular disease, longer pump time, and hypercholesterolemia. Carotid artery stenosis greater than 50% was present in 14.7% of cases. Carotid artery stenosis greater than 75% was not itself associated with increased stroke risk. Most strokes occurred more than 24 hours after surgery. Stroke distribution did not correlate with site of carotid artery stenosis greater than 50%. CONCLUSIONS: Most neurologic events after heart surgery occur in a subset of patients who can be defined before operation. Whereas carotid artery stenosis greater than 50% is a strong risk factor, the role of prophylactic endarterectomy is unclear. Future studies should focus on this high-risk subgroup. A prospective study of prophylactic carotid endarterectomy in patients undergoing coronary artery bypass grafting is needed.     

Delayed full-thickness grafting of lower leg defects following removal of skin malignancies

Cerebral stroke is a serious complication related to carotid endarterectomy (CEA), being most frequently caused by thromboembolic events and less frequently on account of cerebral haemorrhage. The present series comprised five out of 857 (0.6%) patients who had undergone CEA at Oulu University Hospital between the years 1974 and 1993 and suffered a postoperative stroke four to 13 days after surgery due to intracerebral haemorrhage (IH). Preoperatively, all these patients were neurologically intact, with transient ischaemic attacked (TIA) as the main indication for CEA. All five patients had a history of arterial hypertension treated adequately preoperatively, and one patient had high blood pressure levels after surgery. Critical ipsilateral stenosis of the internal carotid artery (> 90%) was detected in the preoperative angiogram in all five cases. The primary outcome after CEA was uneventful in every case, without any signs of neurological deficiency. The symptoms, comprising severe headache, convulsions and/or hemiparesis occurred suddenly four to 13 days (mean seven days) after CEA. The diagnosis of IH was based on computed tomography (CT) findings. All five patients were treated conservatively. Three of them died. We conclude that even normotensive, neurologically intact patients without demonstrable cerebral infarction or postoperative hypertension may suffer cerebral haemorrhage after the relief of high-grade carotid stenosis. The role of possible insufficiency of the autoregulatory mechanisms of the cerebral vasculature on account of long-standing critical stenosis of the internal carotid artery and subsequent uncontrolled hyperperfusion following CEA are discussed.     

Acquired von Willebrand disease in patients with high platelet counts

Operative indication and risk factors for unruptured cerebral aneurysms were discussed. During the past 11 years, 38 aneurysms in 33 patients with a mean age of 54 years were operated on. All aneurysms were located in the anterior circulation; 16 were of carotid artery, 15 of the middle cerebral artery, 4 of the anterior communicating artery, and 3 of the distal anterior cerebral artery. Six cases (18.2%) developed neurological deficits postoperatively. The deficits were permanent in 3 cases (morbidity 9.1%). There was one operative death (mortality 3.0%). Operative risk factors were analyzed in 4 particular cases. Of these 4 cases, two cases had large aneurysms (14 and 16mm in diameter) located at carotid-ophthalmic and at the inferior wall of the carotid arteries, respectively. One developed unilateral blindness possibly due to operative manipulation, and the other showed hemiparesis with aphasia due to postoperative carotid stenosis caused by clipping. Of the rest 2 cases; one with multiple (carotid and middle cerebral) aneurysms developed hemiparesis because of postoperative stenosis of the atheromatous parent artery caused by clipping, and the other, with a large (17mm) aneurysm at the distal anterior cerebral artery, died of postoperative intracerebral hematoma. Both of these cases were associated with cerebral ischemic disease. All cases that developed postoperative neurological deficits had varying degrees of hypertension. Reviewing our series and other reports, it can be said that age is one of the most important factors that influence operative mortality. However, a lower risk of rupture develops as age increases. For those under 70 years of age, operation is considered safe in healthy individuals, especially among those without hypertension. However, in cases where there are large aneurysms, multiple lesions, less accessible locations and cerebral ischemic disease, operative risks should be kept in mind. Operative morbidity in these cases is relatively high compared to that found among others. Therefore, planning a meticulous surgical strategy and further careful operative manipulation are essentials, when surgical treatment is indicated.