Mar. 2, 1998 Magnetic resonance imaging (MRI) of the heart after a heart attack may help determine which patients do well and which ones will later suffer complications such as recurrent heart attack, congestive heart failure, stroke or death, according to a study led by Johns Hopkins researchers.
"This technology could be a cost-effective means to identify which patients need to be monitored in order to prevent or minimize future cardiac events," says João A.C. Lima, M.D., senior author of the study and an associate professor of medicine at Hopkins.
Patients whose MRI scans showed their hearts' capillaries were partially blocked with dying blood cells and debris following a heart attack were more likely to suffer frequent heart complications within the next two years. Capillaries are the body's narrowest blood vessels and are more easily clogged by such debris than larger vessels -- arteries and veins.
In addition, researchers noted that the more serious the heart attack, the higher the patient's risk of later problems.
"Vascular obstruction shown on the MRI scans accurately predicted long-term outcome in patients who had heart attacks," Lima says. "MRI also helped determine the size of the heart attack and the subsequent risk of developing complications."
Results of the study were published in the March 3 issue of Circulation: Journal of the American Heart Association.
Researchers did MRI scans of 44 patients' hearts an average of 10 days after heart attack. Seventeen of the patients returned six months later for a repeat MRI scan.
Of the 11 patients who had vascular obstruction, five (45 percent) experienced at least one significant post-heart attack complication, such as a second heart attack, congestive heart failure, a stroke or death. In contrast, only three (9 percent) of the 33 without obstruction suffered later complications. Problems occurred an average of 14 months after heart attack.
In addition, researchers noted that the risk of having post-heart attack complications increased with the magnitude of the heart attack. Thirty percent of the patients with small heart attacks suffered later complications, compared to 43 percent of those with medium-sized heart attacks and 71 percent of those with large heart attacks.
Blood vessel blockage also increased the risk of patients' developing heart wall damage. Of the 17 patients who returned for a second MRI scan, five of eight patients who had blocked vessels had a thinner heart wall and scar tissue. In comparison, none of the nine patients without blockage developed scar tissue.
"This is one of the first in an increasing number of clinical studies that show us how MRI is likely to become the dominant method for imaging the heart in the near future," says Elias A. Zerhouni, M.D., a co-author of the paper. Zerhouni, professor and director of radiology at Hopkins, is a developer of the MRI techniques used in this study.
The study was supported by the American Heart Association and the National Heart, Lung and Blood Institute.
The study's other authors were Katherine C. Wu, M.D.; Carlos H. Lugo-Olivieri, M.D.; Lili A. Barouch, M.D.; Steven P. Schulman, M.D.; and Roger S. Blumenthal, M.D., of Hopkins; and Robert M. Judd, Ph.D., of Northwestern University Medical School.
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