Two randomized trials suggest (but do not prove) that mechanical thrombectomy improves functional outcomes.

The Interventional Management of Stroke III trial was recently stopped because low-dose intravenous tissue plasminogen activator (IV TPA) combined with thrombectomy or intra-arterial TPA did not improve outcomes compared with standard-dose IV TPA alone. This disappointing preliminary report is now followed by more encouraging publications from two other trials.

SWIFT and TREVO 2 are industry-sponsored randomized trials comparing new stent retrievers with the Merci Retriever, which was FDA-approved in 2004 as the first mechanical thrombectomy device. Both trials enrolled patients who could not receive or had failed to respond to IV TPA and could undergo thrombectomy within 8 hours of stroke onset. Participants had NIH Stroke Scale (NIHSS) scores of 8 (median score, 18–19). Patients underwent up to three attempts with the randomly assigned device before receiving rescue therapy as needed with any approved endovascular technique.

In SWIFT, the Solitaire device significantly outperformed the Merci Retriever in achieving recanalization (69% vs. 30%) and in providing good neurological outcomes (modified Rankin Scale score [mRS] 2; 58% vs. 33%) and lower mortality (17% vs. 38%) at 90 days. Similarly, the Trevo Retriever achieved significantly higher rates of recanalization (86% vs. 60%) and 90-day good outcomes (mRS 2; 40% vs. 22%) than the Merci Retriever.

Comment: Although it is unlikely, the differences in clinical outcomes could reflect harm from the Merci Retriever rather than benefit from the Solitaire and Trevo devices. To definitively establish the effectiveness of thrombectomy, we need trials comparing such new devices with IV TPA alone, perhaps using advanced imaging to identify appropriate candidates. In the meantime, clinicians should strongly consider transferring patients who cannot receive or do not quickly respond to IV TPA to endovascular-capable stroke centers for consideration of available treatment options and enrollment in randomized trials.

Source: Journal Watch Neurology