Last Updated: 2008-04-17 18:14:05 -0400 (Reuters Health)

NEW YORK (Reuters Health) – Final results of the Multi MERCI (Mechanical Embolus Removal in Cerebral Ischemia) trial show that a newer generation mechanical thrombectomy device achieved trends towards higher rates of recanalization and better clinical outcomes compared with first-generation devices in patients with acute ischemic stroke due to large vessel intracranial occlusion.

Although the differences did not reach statistical significance, mortality trended lower and the proportion of patients with good clinical outcomes trended higher, "consistent with better recanalization," Dr. Wade S. Smith of the University of California at San Francisco and colleagues report in the April issue of the journal Stroke.

The Multi MERCI trial compared the performance of the newer generation L5 Retriever thrombectomy device designed to attain a better grasp of the thrombus with that of first generation X5 and X6 devices, as well as to further evaluate the safety and efficacy of combining IV tissue plasminogen activator (tPA) with mechanical clot removal.

A total of 164 patients with large vessel stroke received thrombectomy within 8 hours of symptom onset; 131 of these patients were initially treated with the L5 Retriever.

Primary recanalization was achieved in 75 of 131 vessels (57.3%) in which the newer L5 Retriever was deployed, compared with 15 of 33 vessels (45.5%) in which the older generation X5/X6 devices were deployed (p = 0.25), the investigators report.

With the use of adjunctive tPA when required, recanalization was achieved in 91 of 131 patients (69.5%) in whom the L5 device was used compared with 21 of 33 patients (63.6%) treated with the X5 or X6 devices (p = 0.54).

"Among patients who experienced recanalization, there was a 2-fold survival advantage and a significantly higher proportion of patients lived without significant disability," Dr. Wade and colleagues note.

"Multi MERCI also met its secondary pre-specified safety endpoint: device-related serious adverse events rate of 2.4%," the authors say.

"At present," Dr. Wade and colleagues conclude, "mechanical embolectomy is a useful technique for restoring blood in patients with large vessel acute ischemic stroke, especially in those who are ineligible for thrombolytics or in those who have failed thrombolytic therapy."

Stroke 2008;39:1205-1212.

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