Clinicians know there is a high risk of a future episode in the year following an acute coronary syndrome event such as myocardial infarction or severe angina, and earlier research has documented a surge in plaque accumulation after such events. Previous researchers have even noted accelerated atherosclerosis after angioplasty.

In the current study, French investigators used intravascular ultrasound to obtain three-dimensional images of the lumens of all three coronary arteries during the month following a major event. They found that roughly 80 percent of patients recovering from a first myocardial infarction had unstable plaque some distance from the occlusion, indicating vulnerability to future adverse cardiac events.

“We were very surprised to find that almost four out of five patients present one or more ruptured atherosclerotic plaques besides the culprit lesion,” says lead author Gilles Rioufol, M.D., Ph.D. “We were even more surprised to see that these distinct ruptured plaques involved all three main coronary trunks. In fact, for one in eight patients all three main arteries were affected.”

Rioufol’s team evaluated 72 arteries in 24 patients referred for angioplasty. Imaging with intravascular ultrasound involved threading the probe into a coronary artery during routine angiography and required roughly 10 minutes.

They found that 19 of the patients (79 percent) had at least one plaque rupture other than the one in the culprit lesion. Nearly 71 percent of patients had at least one diagnosed plaque rupture in two of the three arteries; 12.5 percent had at least one rupture in all three arteries. The non-culprit lesions tended to be smaller and less severe than the one causing clinically evident damage.

“At the time of acute coronary syndrome, usually one lesion is clinically active but the entire atherosclerotic coronary tree is destabilized,” Rioufol says.

The findings may lead to new screening tools or treatments. An accompanying editorial says the ability to diagnose vulnerable lesions before they rupture would have “tremendous potential” for prevention of myocardial infarction. Intravascular ultrasound and other invasive and noninvasive techniques may enable doctors to assess individual plaques and overall plaque condition. However, the editorial authors also noted that the current study was limited by the small number of patients studied and the lack of a control group.