Late carotid restenosis: aetiologic factors for recurrent carotid artery stenosis during long-term follow-up.

During a fourteen-year-period 257 patients underwent carotid endarterectomy in an unselected population of 700,000 inhabitants. The incidence of haemodynamically significant restenosis was 13.5% in 133 vessels in 116 patients studied by duplex scanning 28 to 209 months following carotid endarterectomy. The most striking differences between patent and restenosed cases were in serum cholesterol, triglyceride and HDL-cholesterol levels. The patients with a long-term low cholesterol (less than 6.5 mmol/l), low triglyceride (less than 1.42 mmol/l) and high HDL cholesterol (greater than 1.0 mmol/l) levels had significantly less high grade restenosis (P less than 0.05). Apolipoprotein A-I and B had no significant effect, but if the lowest limit of normal apolipoprotein A-I level was considered as 1.27 g/l the difference was significant. The frequency of a high-grade restenosis in patients with diabetes mellitus and coronary heart disease was not significantly increased, but supports the view that these are risk factors in the development of atherosclerotic changes in an operated carotid artery. The incidence of recurrent stenosis appears to be unrelated to hypertension, claudication, obesity, smoking, operative factors or to the indication for surgery. Men were more prone than women to get a high-grade restenosis. Postoperative treatment with acetylsalicylic acid was most effective, the incidence was only half of that expected, whereas the anticoagulants or a combination of acetylsalicylic acid and dipyridamole were of no benefit. Haematocrit, RBC, platelet count and thrombocrit were contradictory.