Etiologic factors for recurrent carotid artery stenosis.

Since 1966, 29 patients with recurrent carotid artery stenosis have been encountered. The mean (+/- SEM) internal between initial carotid endarterectomy and secondary presentation was 67.5 +/- 9.2 months (range 6 to 180 months). There was a disproportionate number of women with recurrent stenosis. The mean age at initial endarterectomy in patients with recurrent stenosis, 54.6 +/- 1.4 years, was significantly less (P less than 0.001) than that of all patients who had endarterectomy. To define the etiologic factors for recurrence, 21 of these patients were matched with case-control patients of the same age and sex who had undergone endarterectomy the same year but did not develop recognized recurrent stenosis. There was no significant difference in the incidence of hypertension, diabetes mellitus, coronary artery disease, bilateral carotid disease, other vascular operations, or family history for atherosclerosis in patients with recurrent stenosis compared to control patients. The indications for primary endarterectomy, angiographic distribution of disease, and operative details were similar in both groups. There was no difference in the incidence of regular, therapeutic aspirin ingestion following initial endarterectomy (52.5% in both groups). There was a striking difference in smoking habits. Ninety-five percent of patients with recurrent stenosis continued to smoke following initial endarterectomy, compared to 23.8% of control patients (P less than 0.001). Lipid fractionation studies were performed in both groups, and there were no significant differences in levels of cholesterol, triglycerides, high-density lipoprotein (HDL)-cholesterol, and total cholesterol/HDL-cholesterol ratio. Dose-response platelet aggregometry detected no differences between groups in the sensitivity of platelets to adenosine diphosphate (ADP), collagen, and epinephrine. Reoperation in patients with recurrent stenosis was associated with minimal morbidity, no deaths, and generally excellent results.