A catheter-based imaging technology called optical coherence tomography (OCT) can successfully identify the characteristics of coronary plaques in patients with various cardiac symptoms. The report from researchers at Massachusetts General Hospital (MGH) will appear in the journal Circulation.
"More than 1.2 million people die from coronary artery disease every year, a quarter of them before or soon after arriving at the hospital," says Ik-Kyung Jang, MD, PhD, director of cardiovascular clinical research in the MGH Cardiology Division and lead author of the current study. "The ability to identify dangerous plaques before they rupture and produce a heart attack or sudden cardiac death will be crucial to innovative preventive therapies."
Plaques are deposits of fats, cholesterol and other materials that collect in major arteries, restricting or sometimes blocking blood flow. While some plaques are relatively stable, others are vulnerable to rupture and release their contents into the bloodstream, causing a blood clot to form. Heart attacks and other acute coronary events usually result from the rupture of high-risk, vulnerable plaques in coronary arteries, and the characteristics of those plaques have been determined primarily by autopsy studies.
OCT uses infrared light delivered via fiberoptic catheter to produce high-resolution, cross-sectional images of blood vessels. Study co-authors Guillermo Tearney, MD, PhD, of the MGH Pathology Department and the Wellman Center for Photomedicine at MGH, and Brett Bouma, PhD, also of the Wellman Center, developed the use of OCT to visualize coronary arteries, including vulnerable plaques. The technology developed in their laboratory was used for this first study to examine the structure of plaques in patients with cardiac disease.
The study enrolled patients scheduled to undergo cardiac catheterization for whom angiograms or other imaging techniques had identified the arterial lesion responsible for their symptoms. Participants either had experienced a recent heart attack or had acute coronary syndrome (ACS), a set of symptoms associated with reduced blood supply to the heart muscle. A third group had stable angina, chest pain that occurs with physical or mental stress, which is not usually related to plaque rupture. Clear OCT images of the suspicious lesions were obtained for 20 heart attack patients, 20 with ACS and 17 with stable angina.