Pedro R. Moreno, M.D., now at Brigham and Women's Hospital and Harvard Medical School in Boston, first author of both studies, and John T. Fallon, M.D., Ph.D., professor of pathology and medicine at The Mount Sinai School of Medicine in New York City, say determining the amount of macrophage infiltration in plaque provides a clinically useful test that is "the first histologic or anatomic prognostic indicator of restenosis."
...Fallon and his colleagues obtained plaque tissue samples from 38 men and 12 women who underwent an artery-clearing procedure called coronary atherectomy at Boston's Massachusetts General Hospital.
Atherectomy is a procedure in which plaque is shaved away and suctioned up."It's like roto-rootering the arteries," Fallon
Analysis of the tissues showed that the 30 people who later experienced restenosis had macrophage-rich areas that were more than twice as large as similar areas in the 20 people who did not develop restenosis.
"The more macrophages we found in the plaque tissue taken out during atherectomy, the more likely that particular patient was to restenose," Fallon
In the second report the researchers suggest that macrophages also may play a role in the rupture of the "fibrous cap" that covers plaque in much the same way that asphalt pavement covers a road.
Using tissue samples from the same 50 patients in the first study, Moreno, Fallon
and their colleagues looked also for a chemical the scavenger cells release called tissue factor.