RECURRENT STROKE AFTER TRANSIENT ISCHEMIC ATTACK OR MINOR ISCHEMIC STROKE - DOES THE DISTINCTION BETWEEN SMALL AND LARGE VESSEL DISEASE REMAIN TRUE TO TYPE

The incidence and vascular type of recurrent ischaemic stroke was stud ied in patients with supratentorial transient ischaemic attacks or non -disabling ischaemic strokes, who were treated with aspirin (30 or 283 mg). Patients were divided into groups with small vessel disease (SVD ) (n = 1216) or large vessel disease (LVD) (n = 1221) on the grounds o f their clinical features and CT at baseline. Patients with evidence o f both SVD and LVD (n = 180) were excluded from further analyses. Duri ng follow up (mean 2.6 years) annual stroke rate was 3.6% in both grou ps. Of the 107 patients with SVD at baseline who had recurrent strokes , 83 proved to have an identifiable infarct: 30 (28%) again had a smal l vessel infarct, 39 (36%) had a large vessel ischaemic stroke and in 14 (13%) the recurrent ischaemic stroke was in the posterior fossa. Of the 110 patients with LVD at baseline and recurrent stroke, 91 had an identifiable infarct: 67 (61%) again had a large vessel ischaemic str oke, 16 (15%) had a small vessel ischaemic stroke, and eight (7%) had the recurrent ischaemic stroke in the posterior fossa. Thus patients w ith a transient ischaemic attack or non-disabling ischaemic stroke cau sed by LVD were more likely to have an ischaemic stroke of the same ve ssel type during follow up than patients with SVD (relative risk 2.2; 95% confidence interval 1.5-3.4). Possible explanations for this diffe rence are: (1) patients with a small vessel ischaemic stroke at baseli ne had both SVD and LVD or were misdiagnosed; (2) recurrent small vess el ischaemic strokes may have occurred more often than reported, becau se they were silent or only minimally disabling; (3) recurrent large v essel ischaemic strokes occurring in patients initially diagnosed as h aving SVD might have been related to potential cardiac sources of embo li that had not been previously recognised; (4) the antiplatelet drug aspirin (30 or 283 mg) prescribed in this patient group may have preve nted thrombosis in small vessels better than in large vessels.