Mechanisms of cerebral artery thrombosis: a histopathological analysis on eight necropsy cases.

The mechanisms of thrombus formation in atherosclerotic cerebral arteries are still controversial, although intraplaque haemorrhage and rupture of the atheromatous plaques have been proposed. A histopathological analysis of segments of the thrombosed large intracranial arteries was carried out on eight patients who died within 28 days after brain infarction. The study revealed occlusive thrombi in six and mural thrombi in two, developing mostly at the site of greatest stenosis or just distal to it. The histological characteristics of the thrombosed arteries were plaque rupture in three, intramural haemorrhage in one, ulceration in one, and thrombosis in the absence of plaque rupture or intramural haemorrhage in three. Occlusive emboli distal to the site of cerebral artery thrombosis (intracranial artery-to-artery thromboembolism) were observed in two. The following conclusions were drawn from the study: 1) plaque rupture or intraplaque haemorrhage is not a sine qua non for cerebral artery thrombosis; 2) occlusions occur at the site of greatest luminal compromise or just distal to it, and 3) non-occlusive mural thrombosis can occur in the absence of plaque rupture and eventually lead to local occlusion or distal embolisation.