Outcome in Patients with Symptomatic Occlusion of the InternalCarotid Artery

OBJECTIVES: to assess whether the risk of recurrent ischaemic stroke in patients with symptomatic internal carotid artery (ICA) occlusion has changed over the past decades, to determine risk factors for the occurrence of ischaemic stroke and to assess the risk of endarterectomy (CEA) of a severe contralateral ICA stenosis. DESIGN: retrospective cohort study. PATIENTS AND METHODS: patients with symptomatic ICA occlusion were identified from duplex registry files between 1991 and 1995. Information was obtained on vascular risk factors, performance of CEA for a contralateral ICA stenosis and on recurrence of ischaemic stroke. The rate of complications occurring within 30 days after CEA of the contralateral ICA in patients with symptomatic ICA occlusion was compared with the risk of CEA in patients with asymptomatic ICA occlusion and severe contralateral ICA stenosis (symptomatic or asymptomatic). RESULTS: ninety-seven patients were identified. Mean follow-up time was 26 months. The annual risk of (non-)fatal stroke was 5.3% for all strokes (95% CI 2. 9%-9.6%) and 3.8% for ipsilateral stroke (95% CI 1.9%-7.7%). Hyperlipidaemia and severe stenosis of the contralateral ICA were independent risk factors. Twenty-two of 32 patients with a severe stenosis of the contralateral ICA underwent CEA, of which one patient died and three suffered a minor ischaemic stroke. The perioperative risk of CEA in the control group of 20 patients with asymptomatic contralateral ICA occlusion was 0% (0 of 20). CONCLUSIONS: outcome in patients with symptomatic ICA occlusion has not substantially improved over the years. CEA for severe stenosis of the contralateral ICA carried a relatively high risk in our series, but deserves to be studied in a controlled design.     

Prevalence, progression and natural history of asymptomatic carotid stenosis: is there a place for carotid endarterectomy?

The purpose of this study was to determine the prevalence, progression and prognosis of asymptomatic carotid artery stenosis in a population of 1198 patients with peripheral arterial disease (n = 986) or aortic aneurysm (n = 212), mean age 67.7 (S.D. = 10.0) years. Patients were recruited from 1985 to 1989 with annual assessment of carotid artery stenosis of over 50% using Doppler peak frequency analysis. Patients were followed up annually until 1990 or their first event, transient ischaemic attack (TIA), amaurosis fugax (AFx), stroke without antecedent TIA, or death (mean follow up 20 months). Life tables were used to determine risk of events in different patient groups. Only 164 (13.7%) patients had a stenosis of over 50% in either of the common or internal carotid arteries, disease was bilateral in 33 (2.8%) patients. A total of 33 patients (2.8%) had over 80% stenosis in common or internal carotid arteries. During follow up 37 (3.1%) patients developed a stenosis greater than 50%. Only 27 (2.3%) patients developed a stroke, 11 of which were fatal. A further 33 (2.8%) suffered a TIA or AFx and a total of 155 patients died during follow up. The total neurological event rate (TIA, AFx and stroke) was significantly associated with the presence of over 50% stenosis, [relative risk (RR) = 2.98, 95% confidence interval (95% C.I.) 1.68-5.29, p less than 0.001] and carotid bruit (RR = 1.16, 95% C.I. 1.23-3.81, p = 0.010). Although risk of stroke was higher in patients with a 50% stenosis, this failed to achieve statistical significance (RR = 1.78, 95% C.I. 0.66-4.80, p = 0.275).(ABSTRACT TRUNCATED AT 250 WORDS)     

Progression of asymptomatic carotid stenosis: A natural history study in 1004 patients

Purpose: The purpose of this study was to delineate the natural history of the progression of asymptomatic carotid stenosis. Methods: In a 10-year period, 1701 carotid arteries in 1004 patients who were asymptomatic were studied with serial duplex scans (mean follow-up period, 28 months; mean number of scans, 2.9/patient). At each visit, stenoses of the internal carotid artery (ICA) and the external carotid artery (ECA) were categorized as none (0 to 14%), mild (15% to 49%), moderate (50% to 79%), severe (80% to 99%), preocclusive, or occluded. Progression was defined as an increase in ICA stenosis to ≥50% for carotid arteries with a baseline of <50% or as an increase to a higher category of stenosis if the baseline stenosis was ≥50%. The Cox proportional hazards model was used for data analysis. Results: The risk of progression of ICA stenosis increased steadily with time (annualized risk of progression, 9.3%). With multivariate modeling, the four most important variables that affected the progression (P < .02) were baseline ipsilateral ICA stenosis ≥50% (relative risk [RR], 3.34), baseline ipsilateral ECA stenosis ≥50% (RR, 1.51), baseline contralateral ICA stenosis ≥50% (RR, 1.41), and systolic pressure more than 160 mm Hg (RR, 1.37). Ipsilateral neurologic ischemic events (stroke/transient ischemic attack) occurred in association with 14.0% of the carotid arteries that were studied. The progression of ICA stenosis correlated with these events (P < .001), but baseline ICA stenosis was not a significant predictor. Conclusion: In contrast to recently published studies, we found that the risk of progression of carotid stenosis is substantial and increases steadily with time. Baseline ICA stenosis was the most important predictor of the progression, but baseline ECA stenosis also was identified as an important independent predictor. Contralateral ICA stenosis and systolic hypertension were additional significant predictors. We found further that the progression of ICA stenosis correlated with ischemic neurologic events but not baseline stenosis. The data provide justification for the use of serial duplex scans to follow carotid stenosis and suggest that different follow-up intervals may be appropriate for different patient subgroups. (J Vasc Surg 1999;29:208-16.)     

Clinical and radiographic risk factors for operative stroke and death in the European carotid surgery trial.

OBJECTIVES: carotid endarterectomy is associated with significant morbidity and mortality. A better understanding of the relationships between baseline characteristics and outcome may help to reduce the risks of surgery. In order to make accurate and unbiased estimates of surgical risk it is important to study cohorts of patients that were established prospectively, where independent physicians assessed outcome, and where the decision to analyse and report the results was not data-dependent. The surgical arm of the European Carotid Surgery Trial (ECST) is such a cohort. METHODS: the 30-day outcome of carotid endarterectomy was analysed in ECST surgery patients in relation to their baseline clinical and angiographic characteristics. The severity of operative strokes was compared with that of strokes that occurred in the medical group. RESULTS: 1729 patients underwent trial surgery. There were 17 deaths (1.0%, 95% CI=0.6-1.6) and 105 non-fatal major strokes (6.1%, 95% CI=5.0-7.3) within 30 days of surgery. The risk of major stroke or death was 7.1% (95% CI=5.9-8.4). The risk of disabling or fatal stroke was 3.0% (95% CI=2.1-3.8). The ratio of disabling to non-disabling operative strokes was similar to that in the medical group. Several baseline characteristics predicted the operative risk of stroke and death in univariate analyses, but only four were independent risk factors in a multiple regression analysis: presentation with cerebral TIA vs ocular ischaemic events only (HR=2.99, 95% CI=1.33-6.69, p=0.008); female sex (HR=2.04, 95% CI=1.37--3.06, p=0.001); systolic hypertension (HR=1.01 per 10 mmHg, 95% CI=1.00-1.02, p=0.03) and peripheral vascular disease (HR=2.17, 95% CI=1.17-2.89, p=0.001). CONCLUSIONS: the operative risk of stroke and death in the ECST was comparable with other prospective studies and trials in which patients were assessed postoperatively by both a physician and a surgeon. Case fatality and disability after operative stroke are similar to strokes that occur on medical treatment only. Several baseline patient characteristics predict surgical risk and it may be possible to use these characteristics to aid patient selection and surgical audit.     

Carotid artery disease and stroke during coronary artery bypass: a critical review of the literature.

OBJECTIVES: to determine the role of carotid artery disease in the pathophysiology of stroke after coronary artery bypass (CABG). DESIGN: systematic review of the literature. RESULTS: the risk of stroke after CABG was 2% and remained unchanged between 1970-2000. Two-thirds occurred after day 1 and 23% died. 91% of screened CABG patients had no significant carotid disease and had a <2% risk of peri-operative stroke. Stroke risk increased to 3% in predominantly asymptomatic patients with a unilateral 50-99% stenosis, 5% in those with bilateral 50-99% stenoses and 7-11% in patients with carotid occlusion. Significant predictive factors for post-CABG stroke included; (i) carotid bruit (OR 3.6, 95% CI 2.8-4.6), (ii) prior stroke/TIA (OR 3.6, 95% CI 2.7-4.9) and (iii) severe carotid stenosis/occlusion (OR 4.3, 95% CI 3.2-5.7). However, the systematic review indicated that 50% of stroke sufferers did not have significant carotid disease and 60% of territorial infarctions on CT scan/autopsy could not be attributed to carotid disease alone. CONCLUSIONS: carotid disease is an important aetiological factor in the pathophysiology of post-CABG stroke. However, even assuming that prophylactic carotid endarterectomy carried no additional risk, it could only ever prevent about 40-50% of procedural strokes.     

A new method for characterizing carotid plaque: multiple cross-sectional view echomorphology

PURPOSE: This study compares the ability of computer-derived B-mode ultrasound gray-scale measurements from a single longitudinal view (SLV) versus multiple cross-sectional views (MCSV) to differentiate symptomatic from asymptomatic carotid plaque causing more than 70% stenosis. METHOD: Seventy-four internal carotid artery (ICA) stenoses (70%-99%; 33 asymptomatic, 41 symptomatic within 3 months) were imaged to obtain the "best" SLV and five to eight MCSV images at 5 mm intervals from the carotid bifurcation. Digitized sonograms were computerized and normalized to the gray scale median (GSM) of blood (0) and vessel adventitia (200). Plaque GSM was determined for each frame (image analysis, MATLAB 5.3). General risk factors for stroke and plaque echogenicity (SLV GSM; minimum MCSV GSM; cross-sectional axial heterogeneity (highest minus lowest MCSV GSM) were determined for each group. RESULTS: Risk factors for stroke were similar in both groups, as was mean SLV GSM: symptomatic, 34 (95% confidence interval [CI], 24.8-43.0), asymptomatic, 43 (CI, 32.6-53.2); P =.1. Minimum MCSV GSM was lower for symptomatic plaque: 7 (CI, 4.2-9.8] vs 18.3 (CI, 12.2-24.5); P =.002. Greater axial GSM heterogeneity was present in symptomatic plaque: 34.5 (CI, 27.2-41.9) vs 16 (CI, 11.0-20.8); P =.0001. CONCLUSIONS: MCSV cross-sectional imaging that enables objective assessment of regional plaque echolucency and heterogeneity is more sensitive than SLV sonography for differentiating symptomatic from asymptomatic plaque.     

Variability in measurement of internal carotid artery stenosis by arch angiography and duplex ultrasonography--time for a reappraisal?

OBJECTIVES: to determine the inter- and intra-observer variability of ICA stenosis measurement using duplex, ECST and NASCET methods. DESIGN: a retrospective review of arch angiograms and carotid duplex scans in 50 patients. MATERIALS AND METHODS: carotid stenoses were calculated by three independent observers according to NASCET and ECST methods. Variation between observers for NASCET and ECST was determined. For each observer, the variation between NASCET and ECST was determined. The variation between duplex and both NASCET and ECST was determined. RESULTS: inter-observer agreement on the degree of ICA stenosis was clinically and statistically good for NASCET but was poorer for ECST. For each observer, comparison between NASCET and ECST showed 95% limits of agreement of around 50 percentage points. Comparison of duplex with NASCET and ECST showed similar 95% limits of agreement. CONCLUSIONS: arch angiography allows reproducible measurement of carotid stenosis by the NASCET method between different observers. For the ECST method, reproducibility is not so good. Variations in results between NASCET and ECST and between angiography and duplex are significant. In view of the similar results of the NASCET and ECST trials, this suggests that degree of stenosis may only be a surrogate marker for outcome following carotid endarterectomy.     

Clinical results of carotid artery stenting compared with carotid endarterectomy

OBJECTIVES: Carotid artery stenting (CAS) is an alternative to carotid endarterectomy (CEA) for treating carotid artery stenosis. We conducted a systematic review and meta-analysis of the clinical trials to date comparing these two procedures to determine their relative safety and efficacy. METHODS: Searches of the Cochrane Controlled Trials Register, MEDLINE, and EMBASE identified two cohort studies and eight randomized, controlled trials (RCTs) comparing CEA and CAS. Meta-analysis was performed for the primary outcome of 30-day stroke or death, using an intention-to-treat analysis. Between-trial heterogeneity was assessed using the chi2 test, and fixed-effects models were used to pool estimates in the absence of heterogeneity. Meta-regression was conducted to investigate potential effect differences by patient, intervention, and trial characteristics. To evaluate the effect of study design and inclusion criteria, sensitivity and subgroup analyses were performed. RESULTS: Ten trials encompassing 3580 patients were analyzed. Patients who underwent CAS had a higher risk of 30-day stroke/death relative to patients who underwent CEA (risk ratio [RR], 1.30; 95% CI, 1.01-1.67). Meta-analysis and meta-regression demonstrated no between-trial heterogeneity. Sensitivity analysis of only RCTs showed similar higher risk for stroke/death (RR, 1.38; 95% CI, 1.06-1.79) in CAS patients. Subgroup analysis of trials enrolling only symptomatic patients showed higher risk of 30-day stroke/death (RR, 1.63; 95% CI, 1.18-2.25), but trials enrolling both symptomatic and asymptomatic patients showed no significant differences (RR, 0.89; 95% CI, 0.59-1.35). CONCLUSIONS: Meta-analysis of trials to date shows CAS is associated with higher 30-day risk of stroke/death compared with CEA. Thus, for the patient at average surgical risk, the role of CAS is unproven, especially for symptomatic patients. And for the patient at high surgical risk, the role of any intervention is uncertain in the setting of competing comorbidities. The results of ongoing clinical trials in this area will likely provide additional evidence to support treatment choices for carotid artery stenosis.     

Improvement of carotid blood flow after carotid endarterectomy--evaluation using intraoperative ultrasound flow measurement.

OBJECTIVES: to examine the relationship between the degree of extracranial internal carotid artery (ICA) stenosis and changes in the ipsilateral ICA blood flow after carotid endarterectomy (CEA). MATERIALS AND METHODS: in a prospective study we studied 51 patients with unilateral 60-99% ICA stenosis (median degree 84%, asymptomatic stenosis n = 13, symptomatic stenosis n = 38). The degree of ICA diameter stenosis was determined by ex-vivo plastination of the surgically removed atherosclerotic specimen and video-assessed planimetry. Intraoperative transit time ultrasound flow measurements of the carotid arteries were performed before and after CEA. Blood flow changes were assessed by mathematical approximations. Statistics were done by use of the Wilcoxon signed Rank test. RESULTS: common carotid artery (CCA) and ICA median blood flow increased after CEA from 370 and 130 ml/min to 450 and 282 ml/min, respectively (p <.001). The relative increase of ICA blood flow was 5% and 18% for 60-69% and 70-79% ICA stenosis (n.s.) but 70% and 247% for 80-89% and 90-99% stenosis (p <.001 each). Mathematical evaluation (fourth-polynomal function) determined a significant increase of carotid blood flow after CEA in ICA stenosis of > or =82.3%. CONCLUSIONS: in the absence of severe contralateral ICA occlusive disease a significant increase of ipsilateral ICA blood flow by CEA can be expected in patients with an ICA stenosis of > or =82.3% (linear degree of stenosis, ECST criteria).     

Diagnostic Performance of Duplex Ultrasonography in the Detection of High Grade Internal Carotid Artery Stenosis

OBJECTIVES: to establish on a national basis whether the diagnostic accuracy of carotid duplex justifies carotid surgery without preoperative angiography. DESIGN: prospective national multicentre study with 10 participating university and county hospitals. MATERIAL AND METHODS: one hundred and thirty-four patients, aged 69+/-9 years, were subjected to routine carotid duplex ultrasonography and angiography. The influence of relevant factors on the relation between ultrasonographic and angiographic variables was evaluated using multiple regression analysis. The capacity of carotid ultrasonography to detect internal carotid artery (ICA) stenosis > or =80% was assessed by receiver operating characteristic analysis. RESULTS: the correlation between peak systolic velocity in ICA (PSV(ICA)) and the angiographic degree of stenosis was strong and significantly influenced only by the applied Doppler angle. Accordingly, the optimal PSV(ICA) cutpoint values for the diagnosis of ICA stenosis > or =80% (ECST method) differed substantially (2.1 and 3.2 m/s) between the two considered angle ranges (0-49 degrees and 50-62 degrees ), the ability to identify high grade ICA stenosis being significantly better at small Doppler angles (0-49 degrees ). CONCLUSION: ultrasonographic duplex technique identifies high grade ICA stenosis with a high degree of accuracy, which can be further improved by the application of small Doppler angles and the use of angle range specific PSV(ICA) cut-off points.     

Grading of internal carotid artery stenosis: validation of Doppler/duplex ultrasound criteria and angiography against endarterectomy specimen.

OBJECTIVES: duplex ultrasound has replaced angiography prior to carotid endarterectomy (CEA) in many institutions. However, the indications for CEA are based on angiographically controlled studies and widely accepted ultrasound criteria do not exist. Consequently, the reliability of Doppler and/or duplex ultrasound to predict a high-grade ICA stenosis has to be proven. DESIGN: prospective validation study. MATERIALS: one hundred and fifty carotid bifurcations assessed by ultrasound and selective angiography and 68 acrylat outcasts of carotid specimen after eversion CEA. METHODS: ICA stenosis was measured angiographically according to the ECST criteria. Combined Doppler acoustic standard criteria (CDASC), peak systolic frequency (PSF), peak systolic velocity (PSV) and end-diastolic velocity (EDV) served as criteria for the ultrasound assessment. These criteria and the results of angiography were compared to the degree of ICA stenosis determined by specimen measurements. RESULTS: the median degree of ICA stenosis as assessed by angiography (82%, range 56-97%) and CDASC (83%, range 50-99%) corresponded well to the specimen measurements (80%, range 50-95%). The sensitivity of angiography and CDASC to predict a 70-90% ICA stenosis (ECST criteria) compared to the specimen measurements was 88% and 95%, respectively. The positive predictive value (PPV) reached 92% and 96%, respectively. CDASC were equivalent to angiography and were superior to the best single frequency or velocity parameters. If CDASC do not indicate a >/=70% ICA stenosis in spite of a PSV >/=180 cm/s and/or an EDV >/=50 cm/s, angiography may detect patients with a >70% ICA stenosis. CONCLUSIONS: CDASC are valid in the quantification of high-grade ICA stenosis. They are more reliable than single velocity and/or frequency measurements. However, if velocity criteria and CDASC do not agree, angiography should be performed.     

Silent cerebral infarction: risk factor for stroke complicating carotid endarterectomy

"Silent" cerebral infarction is found in 20% to 30% of patients with significant internal carotid artery (ICA) disease. Our purpose was to determine whether such "silent" cerebral infarction in the operated carotid territory represents a risk factor for stroke during and immediately after carotid endarterectomy. Over 5 years we followed a cohort of 663 patients with symptomatic and asymptomatic ICA stenosis who were consecutively scheduled for surgery. The stenosis was more than 70% in patients with transient ischemic attacks and more than 95% in asymptomatic stenosis patients. All patients underwent preoperative computed tomography to determine the frequency, extent, and location of any "silent" cerebral infarction. Patients were grouped by the absence or presence of infarction in the operated carotid territory. Among the entire cohort, 20 patients had a major perioperative stroke (3.0%). All deaths were stroke-related. No intracranial bleeding occurred. Major stroke occurred in four (0.8%) patients without appropriate "silent" cerebral infarction, compared with 16 (8.8%) with an appropriate "silent" cerebral infarct (p < 0.001). After adjustment for confounding co-variables (e.g., gender, presence of preoperative symptoms, and age), "silent" cerebral infarction was found to be the only independent predictor of perioperative major stroke for symptomatic and asymptomatic stenosis (overall adjusted relative risk 11.5, 95% confidence interval 3.8-34.9, p < 0.0001). Patients with "silent" cerebral infarction seem to be at increased risk of perioperative stroke. Consequently, preoperative cerebral imaging is important for risk classification.     

Clinical outcome of patients with internal carotid artery occlusion: a prospective follow-up study

PURPOSE: We prospectively evaluated whether, and to what extent, different clinical presentations (symptomatic or asymptomatic) or the presence of atherosclerotic narrowing of the contralateral carotid system modifies the mortality rate and the incidence of nonfatal cerebrovascular events in patients with internal carotid artery (ICA) occlusion. METHODS: A prospective cohort study was conducted in the Unit Care of Angiology at the University Hospital of Padua in Italy. Consecutive patients with ICA occlusion were eligible for the study. Between 1990 and 1991, 41 such patients were identified at our center. All patients were observed prospectively for a mean of 44.5 months, except for one patient who was lost to follow-up after 12 months. Patients with severe (ie, more than 75%) stenosis of the contralateral internal carotid artery were scheduled for thromboendarterectomy. ICA occlusion was objectively documented in all patients by using a combination of echo-color Doppler scanning and continuous-wave Doppler scanning (periorbital flow). RESULTS: The overall mortality rate was 22.0% (95% CI, 10.6-37.6), and the stroke-related mortality rate was 7.3% (95% CI, 1.5-19.9). No differences in overall and stroke-related mortality rates were observed between asymptomatic and symptomatic patients. None of the patients experienced nonfatal cerebrovascular events. CONCLUSION: ICA occlusion seems to represent a relatively benign condition, in both its symptomatic and asymptomatic presentation. The presence of an atherosclerotic stenosis less than 75% of the contralateral ICA does not seem to worsen the prognosis of this condition.     

Asymptomatic carotid lesions after endarterectomy of contralateral carotid artery. Five-year follow-up study and prognosis

Of 185 patients who consecutively underwent carotid endarterectomy five years ago, 135 had a patent asymptomatic contralateral internal carotid artery (ICA). During follow-up (median, 59 months), 36 patients developed new neurologic symptoms (18 strokes and 18 transient ischemic attacks). Thirteen patients developed symptoms referable to the territory of the previously asymptomatic ICA (five strokes and eight transient ischemic attacks). Using life-table analysis, the annual stroke rate was estimated to be 1% and 2.2% considering the previously asymptomatic and symptomatic ICA, respectively. Separating patients according to the degree of stenosis on the preoperative angiogram and according to the presence of ulceration revealed a significantly higher incidence of neurologic events and strokes in patients with stenoses exceeding 50% and/or patients with obvious ulcerations. Although the risk of stroke without warning was increased in these subgroups, we did not consider the risk high enough to warrant prophylactic endarterectomy. An exception enough to warrant prophylactic endarterectomy. An exception may be the patient with a more than 90% stenosis.     

Perioperative risk and late outcome of nonelective carotid endarterectomy.

PURPOSE: In an earlier report of our database for 1924 isolated carotid endarterectomies (CEAs) from 1989 to 1995, multivariable analysis results indicated that the urgency of operation unfavorably influenced the combined stroke and mortality rate (CSM). This study was conducted in an attempt to document the features that contribute to perioperative complications and late outcome in 314 patients for whom CEA was considered to be nonelective because of the severity of previous symptoms, carotid stenosis, or medical comorbidities. METHODS: All the hospital charts and outpatient records were reviewed retrospectively for the 209 men and 105 women who had undergone nonelective CEAs (median age, 69 years). Information regarding the clinical risk factors, the operative indications (CHAT classification), the severity and distribution of carotid disease, and the surgical management were analyzed to assess the impact on the 30-day CSM and on the long-term survival rate and neurologic events during a median follow-up period of 34 months. RESULTS: Previous symptoms had occurred in 285 patients (91%) and included cortical transient ischemic attacks in 47%, amaurosis fugax in 20%, completed strokes in 14%, unstable strokes in 2%, and nonspecific or miscellaneous symptoms in 8%. Preoperative angiography was performed in 308 patients (98%), which confirmed the presence of 80% to 99% ipsilateral carotid stenosis in 79% of the patients and >90% stenosis in 43%. The median interval between presentation and surgical treatment was 2 days, but 48% of the 314 CEAs were performed within 24 hours of presentation. The 30-day CSM was 6.7% and ranged from 3.4% for 29 patients with severe asymptomatic carotid stenosis to 14% for those patients with unstable strokes. The cardiac and pulmonary risk factors were the only variables that were related statistically to the CSM. During the follow-up period, the risk for ipsilateral stroke was significantly higher in women (risk ratio [RR], 2.38; 95% confidence interval [CI], 1.02 to 5.56; P =.04) and in patients with higher gradients of cardiac and pulmonary risk factors (RR, 2.8; 95% CI, 1.6 to 4.8 per gradient increase; P <.001). The risk was significantly lower in patients who had undergone vein patch angioplasty (RR, 0.29; 95% CI, 0.12 to 0. 71; P =.006) in comparison with synthetic patching. However, 38 of the 55 patients (69%) who underwent synthetic patching also had widespread atherosclerosis for which the saphenous veins already had been harvested for coronary bypass grafting surgery or infrainguinal revascularization. CONCLUSION: In our experience, the perioperative risk of nonelective CEA primarily is determined by incidental cardiopulmonary disease. Vein patch angioplasty appears to enhance late results, but the late stroke rate associated with synthetic patching also may have been influenced by the extent of vascular disease in our study group.     

Effect of image normalization on carotid plaque classification and the risk of ipsilateral hemispheric ischemic events: results from the asymptomatic carotid stenosis and risk of stroke study

The aim of this study was to determine the effect of image normalization on plaque classification and the risk of ipsilateral ischemic neurologic events in patients with asymptomatic carotid stenosis. The first 1,115 patients recruited to the Asymptomatic Carotid Stenosis and Risk of Stroke (ACSRS) study with a follow-up of 6 to 84 months (mean 37.1 months) were included in this study. Duplex ultrasonography was used for grading the degree of internal carotid artery stenosis and for plaque characterization (types 1-5), which was performed before and after image normalization. One hundred sixteen ipsilateral ischemic hemispheric events occurred. Image normalization resulted in 60% of plaques being reclassified. Before image normalization, a high event rate was associated with all types of plaque. After image normalization, 109 (94%) of the events occurred in patients with plaque types 1 to 3. For patients with European Carotid Stenosis Trial (ECST) 70 to 99% diameter stenosis (equivalent to North American Symptomatic Carotid Endarterectomy Trial [NASCET] 50-99%) with plaque types 1 to 3, the cumulative stroke rate was 14% at 7 years (2% per year), and for patients with plaque types 4 and 5, the cumulative stroke rate was 0.9% at 7 years (0.14% per year). The results suggest that asymptomatic patients with plaque types 4 and 5 classified as such after image normalization are at low risk irrespective of the degree of stenosis.     

Asymptomatic high-grade internal carotid artery stenosis: is stratification according to risk factors or duplex spectral analysis possible?

High-grade (80% to 99% diameter reduction) asymptomatic internal carotid artery stenoses are associated with an increased neurologic event rate (transient ischemic attack, stroke, asymptomatic internal carotid artery occlusion) compared to less severe asymptomatic lesions. However, many do remain free of associated events. To determine which are most dangerous, we compared risk factors and duplex scan results in two groups with asymptomatic high-grade internal carotid artery stenoses. Group A included 31 patients with 33 unoperated high-grade lesions that remained asymptomatic for at least 12 months (mean 30 months). Group B included 25 patients with 26 initially asymptomatic lesions that subsequently were associated with a neurologic event (mean time to event 7.4 months). The groups did not differ significantly in average age, sex, aspirin use, smoking, or prevalence of hypertension, diabetes, or cardiac disease. With respect to the index high-grade lesion, there was no difference in the frequency of a greater than 50% contralateral internal carotid artery stenosis or greater than 50% ipsilateral external carotid stenosis. However, on duplex scanning, high-grade stenoses with greater than 6.5 kHz end-diastolic frequencies were more frequently associated with an event than high-grade lesions with lower end-diastolic frequency (p = 0.0004). Similarly, seven of 23 lesions (30%) with end-diastolic frequency greater than 6.0 kHz were associated with subsequent internal carotid artery occlusion compared to only one of 29 (3.5%) with end-diastolic frequency less than or equal to 6.0 kHz (p = 0.025). Analysis of internal carotid artery end-diastolic frequency may help select a subgroup of patients with asymptomatic high-grade lesions who are at greatest risk for subsequent neurologic symptoms or ICA occlusion or both.     

Carotid endarterectomy before and after publication of randomized controlled trials

BACKGROUND: In 1991, the European Carotid Surgery Trial (ECST) and the North American Symptomatic Carotid Endarterectomy Trial (NASCET) demonstrated that carotid endarterectomy (CEA), in addition to best medical therapy, significantly reduces ipsilateral stroke in patients with high-grade (70 per cent or more) carotid artery stenosis compared with best medical therapy alone. In 1995, the Asymptomatic Carotid Atherosclerosis Study demonstrated that CEA was of benefit in asymptomatic patients with stenosis greater than 60 per cent. The aim of this paper was to examine how the practice and outcome of CEA have changed since publication of these data. METHODS: A prospectively gathered computerized database comprising 634 consecutive CEAs was studied. Two time intervals were analysed: 1975-1991 inclusive (17 years) and 1 January 1992 to 1 May 1998 (6 years 4 months). RESULTS: Since 1991, there has been a fourfold increase in the number of CEAs performed annually for symptomatic disease. CEA is now performed almost exclusively for high-grade (more than 70 per cent) stenosis. There has been a significant reduction in the total peri-operative neurological event rate (12.5 versus 5.9 per cent, P < 0.05), and the 30-day combined major stroke (Rankin grade 3-5) and mortality rate has fallen to 2.0 per cent. The number of patients who have CEA for asymptomatic disease remains small with 16 of 30 being randomized within the Asymptomatic Carotid Surgery Trial. CONCLUSION: Publication of ECST and NASCET data has been associated with a major increase in the number of CEAs performed for symptomatic disease in this unit. Despite a greater proportion of high-risk patients, the results have improved progressively.     

Outcome of progression from carotid stenosis to occlusion.

The incidence of symptoms at the moment the internal carotid artery (ICA) occludes was assessed in 33 patients. Duplex scanning was performed to determine the progression from stenosis to ICA occlusion. There were 24 patients with a primary stenosis and nine with a restenosis after a carotid endarterectomy. In 18% (6/33) the occlusion was accompanied by a stroke. A transient ischaemic attack (TIA) was seen in 12% (4/33) of patients and 70% (23/33) remained asymptomatic. There was no difference in stroke rate between patients with primary stenosis (4/24:17%) and those with restenosis (2/9:22%). The mean follow-up was 3.2 years and the mean elapse time to occlusion in patients with a stroke was 20 months, with a TIA, 32 months, and in asymptomatic patients, 44 months. It was also shown that a stenosis of greater than 80% diameter reduction had a faster progression (mean 1 year) than a less than 80% stenosis (mean 3.5 years) (p = 0.04). Patients with a stenosis greater than 80% tended to have a higher incidence (40%:2/5) of stroke at the time of occlusion than patients with a stenosis less than 80% (14%:2/28). The results show that an occlusion of the ICA is accompanied by a stroke in 18% of the cases and that patients with a rapid progression and/or greater than 80% stenosis are at high risk. From this point of view a carotid endarterectomy should be considered in order to prevent an occlusion of the ICA and a high risk of stroke.     

Assessment of short-term outcomes for protected carotid angioplasty with stents using recent evidence

BACKGROUND: Carotid artery stenosis is an important risk factor and etiology of stroke. Carotid endarterectomy (CEA) is the gold standard for the treatment of carotid artery stenosis; however, there are potential benefits to adopting the use of carotid artery stenting (CAS) with protection devices. A number of large protected CAS (PCAS) trials are underway, but final results are still several years away. In the interim, numerous PCAS studies have recently been published, and the aim of this study was to combine the published results and examine the outcomes and safety of PCAS. METHODS: Electronic, manual, and bibliographic searches of PubMed and PreMedline were conducted. Proportion differences were calculated for the periprocedural (30-day) outcomes of any stroke and any stroke or death. RESULTS: More than 400 articles were identified. Only 26 studies met the inclusion criteria, resulting in the inclusion of 2,992 patients treated with PCAS. Within this patient group, the pooled perioperative PCAS rate of any type of stroke was 2.4% +/- 0.3% (95% confidence interval [CI]). The 30-day minor stroke rate was 1.1% +/- 0.2% (95% CI), and the 30-day major stroke rate was 0.6% +/- 0.2% (95% CI). The 30-day mortality rate was 0.9% +/- 0.4% (95% CI). CONCLUSION: This study demonstrates relatively low rates of reported perioperative adverse events in PCAS. Selective use of PCAS to treat carotid artery stenosis in those at highest risk for surgical complications is appropriate until the randomized trials of CEA vs PCAS provide concurrent short- and long-term outcome data.