Mechanical Thrombectomy with the Novel NeVa M1 Stent Retriever: Do the Drop Zones Represent a Risk or a Benefit?

Objective: The NeVa M1 thrombectomy device is a novel hybrid-cell stent retriever with multifunctional zones for optimized retrieval of resistant clots located in the M1 segment of the middle cerebral artery. The objective was to evaluate the safety and efficacy of the NeVa in a "real-life" setting.

Methods: Twenty-nine consecutive patients (median age: 77 years) treated with the NeVa M1 for acute ischemic stroke of the M1 segement were retrospectively reviewed. First-pass and final modified thrombolysis in cerebral infarction (mTICI) scores, device-related complications, symptomatic intracranial hemorrhage, and 90-day modified Rankin scale (mRS) scores are reported. Primary outcome parameters were first-pass mTICI 2b-3 reperfusion and mRS 0-2 at 90 days.

Results: Median National Institutes of Health Stroke Scale scores decreased from 16 to 12 after treatment. mTICI 2b-3 reperfusion rates were 55% after the first pass, 79% after 1-2 passes, and 100% after the final pass. mTICI 2c-3 was obtained in 48% after the first pass, 62% after 1-2 passes, and 72% after the final pass. Rescue treatment was performed in 4 patients (14%). Device-related complications included 1 asymptomatic caroticocavernous fistula, 1 asymptomatic M2 dissection, and 1 symptomatic intracranial hemorrhage. The procedure-related vasospasm rate was 48%. A 90-day mRS of 0-2 was achieved by 31%.

Conclusions: The NeVa M1 provides a high first-pass complete reperfusion rate with an adequate safety profile. To retrieve resistant clots, the stent design exerts high mechanical traction forces, which may trigger vasospasm and vessel wall damage. Large, comparative studies are warranted to draw a definite conclusion on this device.