Aspirin failure in symptomatic atherosclerotic carotid artery disease

Over a 26-month period 27 urgent carotid endarterectomies were performed on patients who had been taking antiplatelet aggregating drugs for 6 months to 2 years. Angiography confirmed an original diagnosis of symptomatic extracranial carotid artery stenosis and ulceration in all patients. Nineteen had been started on dosages of aspirin from 325 to 1,300 mg/day, and eight started on aspirin plus persantine. Compliance to aspirin use appeared high. All had partial or total resolution of the ischemic symptoms after aspirin therapy was instituted. On readmission three patients had early stroke in evolution, and 24 had crescendo transient ischemic attacks. Reevaluation included cerebral angiography which confirmed progression of carotid artery disease to 90% or greater stenosis in each instance. All patients underwent successful carotid endarterectomies. A review of history of these 27 in the urgent group as opposed to the 45 symptomatic carotid patients who were electively operated on in the same time period revealed no significant (P greater than 0.10) differences in incidence of risk factors for atherosclerosis. However, none of the elective group had regularly taken aspirin. It would appear that aspirin decreased ischemic symptoms in the patients who underwent urgent operation by its antithromboxane effect, inhibiting platelet aggregation and embolization. However, aspirin appeared to have a deleterious effect on these patients by allowing their carotid disease to progress to a dangerous state by eliminating the symptoms of progressive carotid artery atherosclerosis or by accentuating the process of atherosclerosis possibly by inhibition of arterial prostacyclin.