Arterial and Cardiac Clots Found Similar

A new study shows that contrary to traditional beliefs, stroke-causing clots derived from arterial and cardiac sources are composed of similar components.

Researchers from the University of California, Los Angeles (UCLA, USA), studied clots removed from the brain blood vessels of 25 stroke victims. The clots were retrieved during treatment using a novel mechanical clot-retrieval device called the MERCI (mechanical embolus removal in cerebral ischemia) retriever. The removed clots were analyzed under the microscope to compare their component structures.

Unexpectedly, no two retrieved clots looked the same, but the large majority (75%) of thromboemboli shared architectural features of random fibrin: platelet deposits interspersed with linear collections of nucleated cells (monocytes and neutrophils) and confined erythrocyte-rich regions. The same components were involved in both the newly formed and mature clots. While red blood-cell accumulations had previously been considered to dominate the structure of clots that formed within a heart chamber, the new results suggest that red cells often accumulate on clots after impaction in the brain artery. The findings were reported in the June 29, 2006, online issue of the journal Stroke.

"This could potentially change the way we treat clots,” said co-author Dr. Jeffrey Saver, professor of neurology at the David Geffen School of Medicine at UCLA and co-director of the UCLA Stroke Center. "Now that we can retrieve clots, we can analyze their molecular composition and determine the combination of mechanical therapies and clot-dissolving agents most likely to allow us to open up arteries.”

The MERCI retriever, which allows removal and analysis of clots within six hours of symptoms onset, was invented at UCLA and sponsored by Concentric Medical (Mountain View, CA, USA). The U.S. Food and Drug Administration (FDA) approved the MERCI Retriever in 2004 for removal of clots from brain arteries in patients experiencing ischemic stroke within the first eight hours of stroke onset.



Related Links:
University of California Los Angeles
Concentric Medical