Introduction: Histopathological analysis of the thrombi, which was retrieved from stroke patients with large-vessel occlusion during mechanical thrombectomy, may provide information about underlying pathologies. It is likely that the size of the thrombi differ between stent retriever and aspiration catheter.
Objective: This study aimed to evaluate the thrombus composition and its association with radiological findings, stroke subtypes, and reperfusion times.
Methods: From June 2014 to August 2016, 51 patients were treated at our hospital by mechanical thrombectomy using stent retriever and/or aspiration catheter. The received thrombi were subjected to semi-quantitative analysis to quantify red blood cells, platelet, and/or fibrin in the overall area. We divided the patients into two groups according to the predominant composition of the thrombus: red thrombus group or white thrombus group. These two groups were compared with respect to imaging, clinical, and neurointerventional data.
Results: Histopathological analysis of retrieved thrombus from 44 patients with acute stroke due to internal carotid artery, middle cerebral artery, or basilar artery occlusion was performed. There were no significant changes with respect to the time from onset to reperfusion, time from puncture to reperfusion, and type of atrial fibrillation (paroxysmal or persistent). Postoperative stenotic lesion was significantly higher in patients with white thrombi than in those with red thrombi (83% vs 19%, p = 0.001). Preoperative susceptibility vessel sign on magnetic resonance imaging correlated with the proportion of red thrombi than with that of white thrombi (59% vs 33%, p = 0.04). The maximum diameter of thrombi was significantly larger in the combination Penumbra aspiration catheter group compared with that in the non-combination group (9.2 ± 3.7 vs 5.3 ± 4.7mm, p < 0.001).
Conclusion: Histological thrombus features vary significantly according to the underlying cause and may help to differentiate between large-artery atherosclerosis and cerebral embolism. Aspiration first pass technique could retrieve a large thrombus.