Life expectancy and late stroke following carotid endarterectomy

Surgical versus nonoperative treatment of symptomatic carotid stenosis. 211 patients documented by intravenous angiography

From 1980 through 1982, intravenous extracranial digital subtraction angiography (DSA) was performed in 6684 patients at the Cleveland Clinic. Of these, 211 previously unoperated patients had prior transient ischemic attacks (TIA) or strokes in conjunction with greater than 50% carotid stenosis on unequivocal DSA studies. Nonoperative management was employed in 126 patients, including 120 (84%) who received antiplatelet therapy or formal anticoagulation. The remaining 85 patients underwent carotid endarterectomy. During a mean follow-up interval of 36 months, there was no overall difference in survival, late TIA, or stroke between the nonoperated and surgical cohorts. However, parity was maintained in these groups only because of the prevalence of intermediate (50-69%) stenotic lesions and stable internal carotid occlusions in the nonoperated group. Carotid endarterectomy provided superior stroke prevention for patients with greater than 70% unilateral stenosis (p = 0.04), for those with greater than 50% bilateral stenosis (p = 0.004), and for those with internal carotid occlusions associated with greater than 50% contralateral stenosis (p = 0.03). The special risk of such discrete subsets should be recognized in order to plan appropriate treatment at the present time, as well as to conduct safe clinical trials in the future.

Noninvasive assessment of stroke risk in asymptomatic and nonhemispheric patients with suspected carotid disease. Five-year follow-up of 294 unoperated and 81 operated patients

Based on the assumption that greater than or equal to 50% stenosis of the internal carotid artery increases stroke risk, noninvasive tests are being used to screen patients for prophylactic carotid endarterectomy. To assess the validity of this concept, 104 asymptomatic and 190 nonhemispheric patients referred for cerebrovascular tests were reviewed after 5 years. Carotid stenosis greater than or equal to 50% predicted a 15% stroke incidence at 2 years compared to a 3% incidence with 1-49% stenosis (p less than or equal to 0.05). Five-year cumulative stroke incidence was 21% with greater than 50% stenosis, 14% with 1-49% stenosis (NS), and 9% with 0% stenosis (p less than 0.05). Stenosis greater than or equal to 50% predicted increased cardiac mortality (p less than 0.025). Hypertensive patients, greater than 70 years, with greater than or equal to 50% stenosis had a 37% incidence of stroke; normotensive patients, less than 70 years, with or without stenosis, had few strokes. In patients with greater than or equal to 50% disease, surgery reduced the 5-year stroke rate from 21 to 8% (p less than 0.05), mitigated the effects of age and hypertension, and improved survival. Noninvasive test results must be considered in conjunction with age and hypertension in predicting stroke risk.

Colour-coded carotid Doppler imaging: an angiographic comparison of 324 bifurcations

The accuracy of a colour-coded Doppler ultrasound imaging system in the assessment of the extracranial carotid tree is presented. A series of 162 consecutive patients (324 bifurcations) were assessed with angiographic control. Doppler frequency shifts of between 3600 and 5000 Hz, corresponding to yellow on the colour code, detected carotid arteries that were stenosed greater than or equal to 50% with a sensitivity of 95%, a specificity of 72% and an overall accuracy of 81%. At frequency shifts of over 5000 Hz corresponding to the blue code, the sensitivity was 83%, specificity 90% and accuracy 87%. With highly stenosed lesions (90-99%), 24% were incorrectly diagnosed as occlusion by the imager. In those cases with a haemodynamically significant lesion on one side there is no evidence of a compensatory increase in velocity on the other side. The technique is readily learnt but an awareness of its pitfalls is essential for accurate scanning and these are discussed. Carotid Doppler imaging has superseded phono-angiography and peri-orbital Doppler examination in our laboratory and is used with the oculoplethysmograph in the routine assessment of patients with suspected carotid bifurcation disease.

[Late results following carotid endarterectomy]

186 carotid endarterectomies (142 patients) were performed under regional anaesthesia between 1976 and 1983: 32% in asymptomatic stage, 36% in TIA, 4% in frank stroke, 28% in completed stroke. Postoperative mortality was 3.8%, neurologic deficit following endarterectomy 4% (2% transient, 2% permanent). Patients were followed-up six months to seven years after the operation: The incidence of late stroke amounted to 7% (11% in TIA-patients, 5% in patients with completed stroke before endarterectomy). 24% of the operated patients died during the follow-up period, 46% because of myocardial infarction or heart failure, 14% because of stroke. Recurrent stenosis occurred in 6% (indirect Doppler-sonogramm), two patients (3%) with symptomatic recurrent stenosis underwent reoperation.