Mohammed A Almekhlafi MD, FRCPC, Abstract Co-Author: Nothing to Disclose

Bijoy Menon MBBS, MD, Abstract Co-Author: Nothing to Disclose

Andrew Demchuk MD, Abstract Co-Author: Nothing to Disclose

Mayank Goyal MD, FRCPC, Presenter: Shareholder, Calgary Scientific, Inc Research grant, Bayer AG

To compare the complete recanalization rates, puncture-to-recanalization times, and complications of the MERCI device, Penumbra System (PS), and Retrievable Stents (RS: Solitaire or Trevo) in acute ischemic stroke treatment.

We conducted a systematic review and meta-analysis of studies or abstracts published until February 2011 reporting original data on 10 patients or more.

We identified 14 eligible studies: 4 on MERCI device (N=357), 5 on PS (N=256), and 5 on RS (N=135); none was randomized. All studies reporting on MERCI were prospective and half were multicentre while 40% of those reporting on PS were multicenter and 60% prospective, and all studies reporting on RS were single-center experiences with 40% being prospective. There was significant heterogeneity in the reporting of methods and procedural outcomes. Complete recanalization (TIMI 3) was achieved in 16.8% of patients treated with MERCI compared to 33.6% with PS and 54.8% of those treated with RS. Any recanalization (TIMI 2/3) was achieved in 59.1% of MERCI-treated patients compared to 86% with PS and 94.8% of RS. Using the random effect model, mean puncture-to-recanalization time for MERCI device was 117 minutes (95%CI 100.4 to 133.5), 63.5 minutes for PS (95%CI 35.6 to 91.3), and 58.5 minutes for RS (95% CI 44.5 to 72.4). Distal emboli were reported in 1.1% of MERCI studies compared to 6.6% of PS and 3% of RS studies. Symptomatic intracranial hemorrhage was reported in 8.4% in MERCI studies, 9.8% of PS studies and 9.6% of RS. The three-month mortality rate was 37.8% in MERCI studies, 20.7% in PS, and 12.3% in RS studies. Functional independence (mRS≤2) at three months was not reported in all studies. It was achieved in 31.5% of studies reporting on MERCI, compared 32% of PS, and 47.4% in RS studies.

In this meta-analysis, retrievable stents were associated with the highest recanalization rates, lowest mortality and better functional outcome. While some of these results are attributed to the device used, improved operators’ learning curve, availability of other mechanical devices, and improved stroke care are among the other contributing factors.

A standardized approach to reporting outcomes of endovascular stroke therapies is imperative to enable any meaningful comparison of available devices.

Almekhlafi, M, Menon, B, Demchuk, A, Goyal, M, A Meta-Analysis of Observational Studies Comparing Procedural Efficacy of the MERCI Device, Penumbra System, and Retrievable Stents in the Endovascular Management of Acute Ischemic Strokes.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11013594.html