The Influence of Vessel Curvature and Thrombus Composition on the Effectiveness and Outcomes of Thrombectomy in the Case of Acute Ischemic Stroke

Abstract

Introduction. It is believed that vascular anatomy has a direct influence on the complexity and course of mechanical thrombectomy, and its outcome determines the degree of reperfusion and clinical effect.
 Aim. To analyze the influence of the curvature of the intracranial arteries and the composition of the thrombus on the results of thrombectomy.
 Materials and methods. 64 patients who underwent mechanical thrombectomy for acute proximal occlusion of the ICA or MCA were prospectively examined. (44man/20women among them, the age of the patients ranged from 47-89years (67.2±1.2). The study was performed by measuring the ICA-M1 angle on angiograms in direct projection. Angles were compared between patients with successful (mTICI group 2b/3) and unsuccessful (mTICI group 0-2a) reperfusion. The functional result was evaluated according to the mRS scale as positive (0-3) and negative (4-5). Removed thrombi were examined by light microscopy with hematoxylin-eosin and orange-red-blue staining.
 Results. Among patients of the mTICI 2b/3 group, a larger angle of the ICA-M1 was measured (126.4±2.8°) compared to patients in the mTICI 0-2a group - 107.1±4.9° (p=0.05). Among patients with 1-2 passages, statistically significantly larger ICA-M1 angles were recorded (129.8±3.3°) than among patients with a number of passages >2 (109.2±5,7°, p<0.02). The duration of mechanical thrombectomy was <60min among patients with larger angles of the ICA-M1 (127.6±4.4° vs. 119.6±4.5°) than in patients with long interventions (>60 min) (p<0.05). Successful reperfusion (group mTICI 2b/3) was achieved in 47 (73.4%) patients. A clinically positive result(mRS 0-3) was observed among 37(57.8%) patients.
 During microscopic examination of thrombi among patient groups mTICI 0/2a, fibrin threads with signs of aging with purple and blue color were present on the periphery (24-48hours). With a favorable outcome of the operation, the coagulated fibrin fibers were stained red (<16hours).
 Conclusions. With a smaller curvature of the ICA and its branches, and in the presence of "fresh" thrombi, the efficiency of operations increases, and the number of passages and the duration of mechanical thrombectomy decrease. The neurological status of patients at admission correlates with the functional outcome at the time of discharge.