STEMI既往者に対し完全血管形成術は安全である (Abstract 410-14)

Patients who experience an ST segment elevation myocardial infarction (STEMI) and suffer from substantial narrowing in multiple heart arteries may benefit from receiving angioplasty in constricted arteries not affected by the MI, thereby reducing the need for future angioplasty, according to research presented at the American College of Cardiology's 64th Annual Scientific Session.

The study is the largest prospective, controlled trial to evaluate whether patients should receive preventive angioplasty, also known as complete revascularization, after receiving emergency angioplasty in response to an MI. A total of 627 STEMI patients in Denmark who survived an initial angioplasty procedure were randomized to receive either standard follow-up care or complete revascularization two days after the emergency procedure.

After an average of 27 months, 17 percent of the patients who received standard care returned for unplanned angioplasty or bypass surgery compared to only 5 percent of the patients who received complete revascularization. Rates of MI and death were comparable between the two groups.

Of the patients who returned for unplanned angioplasty, more than 40 percent of patients in both groups were considered urgent revascularizations.

"Our results show that it is safe to do a complete revascularization in this particular patient population," said Thomas Engstrøm, M.D., Ph.D., senior consultant at the University of Copenhagen and the study's lead author. "We think this approach should be implemented in the guidelines, as it may help patients avoid returning for future angioplasty in an urgent manner."

While this approach was found to reduce the likelihood of unplanned angioplasty or bypass, the study authors were surprised to find there were no significant differences in rates of death or repeat MI.

"The neutral impact from complete revascularization on death and repeat heart attacks is informative for physicians [because] if their patients have other risk factors, like poor compliance with dual antiplatelet medical therapy or a need for complex angioplasty that may lead to unsuccessful results, a more conservative approach can be taken without increasing the risk for death or MI," he said.

About 40 percent of STEMI patients are found to have narrowing of other coronary arteries in addition to the one with the blockage that caused their MI. Multivessel disease can substantially increase the risk of death and other cardiac events, such as repeat MI or need for urgent angioplasty. According to the study authors, there is no consensus regarding treatment of multivessel disease; therefore, approaches to reduce the risk are needed.

The trial, which took place in Denmark, included patients who underwent successful angioplasty for STEMI and had multivessel disease with narrowing of at least 50 percent, as well as a fractional flow reserve of less than 0.80 measured with a guide wire-based procedure that can accurately measure blood pressure and flow through a specific part of the coronary artery.

The results add to mounting evidence showing preventive revascularization to be beneficial in certain patients.

Engstrøm said research is needed to look into whether or not complete angioplasty can be conducted earlier than two days post-STEMI. The researchers' rationale for this timeframe—two days after the initial procedure—was to let the patient's body recover and to allow for more accurate identification of arteries in need of angioplasty.

The study was funded by the Danish Agency for Science, Technology and Innovation and the Danish Council for Strategic Research.