Angiographic Baseline Proximal Thrombus Appearance of M1/M2 Occlusions in Mechanical Thrombectomy

Purpose Analyzing stroke thrombi has proven to be valuable in prognostication and risk stratification of stroke etiology, reperfusion success and outcomes. The aim of this study was to test if the baseline appearance of the proximal thrombus on digital subtraction angiography (DSA) can predict these parameters in acute ischemic stroke patients treated with mechanical thrombectomy. Methods The appearance of the most proximal part of the thrombus was determined based on DSA. Thrombus perviousness, density, and histology were measured beforehand as described previously. Baseline, technical, and outcome variables were compared using the chi(2)-test, analysis of variance and the Kruskal-Wallis test. Results A total of 144 stroke patients with M1 and M2 occlusions could be included in this present study. Of the patients 60.4% had a cutoff, 27.1% a tapered, and 12.5% a meniscus/tram-track appearance of the thrombus on baseline DSA. The number of maneuvers was higher in the cutoff cohort (P= 0.003). Age (P= 0.777), female sex (P= 0.936), administration of intravenous thrombolysis (P= 0.364), percentage of M1 occlusions (P= 0.194), Alberta Stroke Program early computed tomography score (ASPECTS, P= 0.256), usage of balloon guide catheters (P= 0.367), general anesthesia (P= 0.184), procedure time (P= 0.214) and symptom onset to groin puncture time (P= 0.114) did not significantly differ. Alongside a lower National Institutes of Health scale (NIHSS) score on admission (P= 0.085), good functional outcome was favorable for the meniscus/tram-track cohort (P= 0.030). Stroke etiology according to the trial of Org 10172 in acute stroke treatment (TOAST) criteria as well as thrombus perviousness, density, and histology showed no association with the thrombus appearance. Conclusion Baseline cut off thrombus appearance predicts a higher number of thrombectomy maneuvers. In day to day practice this may prepare the neurointerventionalist for a more challenging endovascular procedure ahead. Stroke etiology, clinical outcomes and thrombus-specific characteristics did not show any associations with the thrombus appearance.