Optimal strategy for mechanical thrombectomy based on the preoperative imaging features of the thrombus

Successful recanalization is not achieved in approximately 20 % of stroke patients who underwent mechanical thrombectomy, possibly due to the characteristics of the underlying thrombus. This study aimed to identify the most appropriate thrombectomy strategy based on the preoperative imaging features of the thrombus.

We retrospectively evaluated the data of 70 patients who underwent mechanical thrombectomy. Thrombus density was assessed using non-contrast computed tomography (ΔCT values) and CT angiography (thrombus permeability). Difficult-to-retrieve thrombi were categorized based on the cutoff values (ΔCT <10 Hounsfield units and/or thrombus permeability <9 Hounsfield units). Favorable outcomes (modified Rankin scale score of 0-2) and successful recanalization (Thrombolysis in Cerebral Infarction grade 2b or 3) were evaluated. We also analyzed the interaction between thrombus imaging features and thrombectomy strategy (stent retriever (SR) alone vs. combined strategy) and its effect on recanalization.

Patients with favorable outcomes and successful recanalization had statistically higher ΔCT values and thrombus permeability. Multiple logistic analyses identified difficult-to-retrieve thrombi as independently associated with fewer favorable outcome (odds ratio: 0.12 [0.03-0.36], p < 0.001). The combined strategy demonstrated significantly greater effectiveness in achieving successful recanalization for difficult-to-retrieve thrombi compared with the SR-alone strategy (84.2 % vs. 50 %, odds ratio: 5.33, 95 % CI: 1.14-24.90, p = 0.038). However, normal thrombi demonstrated comparable responses with both strategies (92.3 % vs. 100 %, p = 0.394).

Given its procedural simplicity and cost-effectiveness, the SR-alone strategy may be effective for normal thrombi, whereas the combined strategy may be preferable for difficult-to-retrieve thrombi.