This Article Full Text Full Text (PDF) All Versions of this Article: 37/5/1340    most recent 01.STR.0000217436.17531.fav1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Saver, J. L. Search for Related Content PubMed PubMed Citation Articles by Saver, J. L. Pubmed/NCBI databases Medline Plus Health Information Stroke Related Collections Acute Cerebral Infarction Emergency treatment of Stroke Related Articles

(Stroke. 2006;37:1340.)
© 2006 American Heart Association, Inc.

Controversies in Stroke

Does the Merci Retriever Work?

For

Jeffrey L. Saver, MD

From the Stroke Center and Department of Neurology, David Geffen School of Medicine of the University of California, Los Angeles.

Correspondence to Jeffrey L. Saver, MD, UCLA Stroke Center, 710 Westwood Plaza, Los Angeles, CA 90095. E-mail jsaver@ucla.edu

Section Editors: Geoffrey A. Donnan MD, FRACP Stephen M. Davis MD, FRACP

Key Words: acute stroke • brain ischemia • clinical trials • embolectomy • therapeutics

An extract of the first 250 words of the full text is provided, because this article has no abstract.

Technically, it works. And remarkably so. The Merci Retriever is a mechanical embolectomy device designed to reopen occluded vessels by extracting occlusive thrombi from the cerebral vasculature. In the Mechanical Embolus Removal in Cerebral Ischemia (MERCI) trial (parts I and II combined), among 151 patients enrolled in the intention-to-treat group; partial or complete recanalization by use of the device alone was achieved in 46%.¹ This rate substantially exceeded that in the prespecified comparator group—patients enrolled in the control arm of the Prolyse in Acute Cerebral Thromboembolism (PROACT-II) trial (18%). The associated probability value of <0.0001 indicates a less than 1 in 10 000 chance that this result occurred by chance. The Merci Retriever indeed works.

And it works well where we most need it to work: on proximal occlusions for which there was previously no good therapy. Proximal carotid terminus and M1 middle cerebral artery thrombi respond poorly to IV or intra-arterial fibrinolytic therapy, likely attributable in large part to the sheer volume of the clot burden requiring enzymatic digestion. The average volume of carotid terminus thrombi (0.4 ml) is more than an order of magnitude larger than that of M2 middle cerebral artery division thrombi (0.03 ml).² Such large clot burdens resist enzymatic digestion. For example, IV tissue plasminogen activator recanalizes only 10% of carotid terminus occlusions.³ In contrast, the Merci Retriever disposes of large proximal clots with comparative ease (53% recanalization rate in the MERCI Trial).

The Merci Retriever perfectly complements lytic therapy. The device’s size limits its . . . [Full Text of this Article]

Related Articles:

Does the Merci Retriever Work?: Against

Lawrence R. Wechsler
Stroke 2006 37: 1341-1342. [Extract] [Full Text] [PDF]

Merci Retriever: Does it Work?

Stephen M. Davis and Geoffrey A. Donnan
Stroke 2006 37: 1343-1344. [Extract] [Full Text] [PDF]

This article has been cited by other articles:

				The IMS II Trial Investigators The Interventional Management of Stroke (IMS) II Study Stroke, July 1, 2007; 38(7): 2127 - 2135. [Abstract] [Full Text] [PDF]