Clinical, angiographic and radiographic outcome differences among mechanical thrombectomy devices: initial experience of a large-volume center

Background and purpose: Higher reperfusion rates have been established with endovascular treatment of acute ischemic stroke (AIS). There are limited data on the comparative performance of mechanical thrombectomy devices.

Methods: A retrospective single-center analysis was undertaken of all consecutive patients who underwent thrombectomy using Merci, Penumbra or stent retrievers (SR) from September 2010 to November 2012. Baseline characteristics, rates of successful recanalization (modified Thrombolysis in Cerebral Infarction (mTICI) score 2b-3), symptomatic intracerebral hemorrhage (sICH), final infarct volume, 90-day mortality and independent functional outcomes at 90 days were compared across the three devices.

Results: Our cohort included 287 patients. There were mild imbalances in baseline characteristics with trends towards higher National Institutes of Health Stroke Scale (NIHSS) score in patients in the Merci group (SR=18 vs Merci=21 vs Penumbra=19, p=0.06) and lower Alberta Stroke Program Early CT Score (ASPECTS) in patients in the SR group (>7: SR=51% vs Merci=61% vs Penumbra=62%, p=0.12). On univariate analysis there were no differences in the rate of sICH (SR=7% vs Merci=7% vs Penumbra=6%, p=0.921) and infarct volume (SR=61.5 mL vs Merci=69.5 mL vs Penumbra=59.2 mL, p=0.621). Trends towards better functional outcomes were found with Penumbra and SR vs Merci (41% vs 36% vs 25%, respectively, p=0.079). Complete or near complete reperfusion (mTICI 2b-3) was higher in the SR and Penumbra groups than in the Merci group (86% vs 78% vs 70%, respectively, p=0.027). Binary logistic regression showed that SR was an independent predictor of good functional outcome (OR 2.27, 95% CI 1.018 to 5.048; p=0.045).

Conclusions: Although our initial data confirm the superiority of SR technology over the Merci device, there was no significant difference in near complete/complete reperfusion, final infarct volumes or clinical outcomes between SR and Penumbra thromboaspiration.