Marder VJ et al. (2006) Analysis of thrombi retrieved from cerebral arteries of patients with acute ischemic stroke. Stroke 37: 2086–2093

Researchers from the David Geffen School of Medicine at the University of California, Los Angeles, have carried out a histopathological study of thromboemboli retrieved from the cerebral artery networks of patients with acute ischemic stroke. A mechanical retrieval device allowed the researchers to study emboli that would previously have been inaccessible.

Marder et al. removed thrombi from 25 patients shortly after the defined onset of stroke symptoms (mean delay between symptom onset and retrieval 6.2 ± 3.1 h). Most thromboemboli were retrieved in fragments, although removal as a single mass was achieved in 36% of cases. Only thromboemboli <3 mm wide reached the middle cerebral artery, whereas emboli extracted from the internal carotid artery reached a maximum width of 5 mm. Each thrombus sample had a unique histological appearance, despite the majority being composed of a complicated pattern of platelet and fibrin areas combined with deposits of nucleated cells and erythrocytes. This structural composition is consistent with clinical trial data indicating that both antiplatelet and anticoagulant agents are beneficial in stroke prevention. No relationship was found between thrombus histology and presumed cardiopathic or arteriopathic etiology or occlusion location, and no calcific deposits or cholesterol crystals were observed in any of the samples.

In addition to the 25 patients in whom thrombus extraction was successful, 29 patients underwent unsuccessful thrombus retrieval. The success of thrombus extraction was negatively correlated with patient age, but no relationship was found with sex, the timing of the retrieval procedure, stroke subtype or site of the thromboembolism.