Angiographic analysis of intravascular thrombus volume in patients with acute ischemic stroke

Purpose: To investigate the role that intravascular thrombus volume plays in mechanical thrombectomy and dose-titrated algorithms using pharmaceutical thrombolytic therapies. Methods: The angiographic studies of 33 consecutive patients (19 women; mean age 66±11 years) who underwent endovascular treatment for acute ischemic stroke were reviewed. A double-injection technique was utilized that involved 2 catheters for simultaneous injection of contrast proximal and distal to the thrombus to delineate its boundaries. The thrombus volume was calculated using the formula for cylindrical objects after measuring its length and diameter. Results: The volume of the 36 thrombi measured in the study group was 46±59 mm³. The mean length and diameter were 10±6 and 2±1 mm, respectively. The time between symptom onset and acquisition of angiographic images ranged from 167 to 589 minutes (mean 336±109). In a multivariate analysis, thrombus volume was not associated with any recanalization (odds ratio 2.4, 95% CI 0.02-191) after adjusting for initial occlusion grade, time between symptom onset and angiography, and previous intravenous use of thrombolytic agents. Volume capacities for retrieval devices to retain 50% and 75% of the thrombi were estimated as 29.2 mm ³ and 55.3 mm³, respectively. Conclusion: The large variation in thrombi volume must be considered in designing retrieval devices to optimize their performance.