WASHINGTON – Using fractional flow reserve (FFR) to revascularize noninfarct coronary arteries during percutaneous coronary intervention (PCI) significantly reduced the subsequent 1-year risk of major adverse cardiovascular events among patients with ST-segment myocardial infarction and multivessel disease, according to the results of a randomized, multicenter trial.

Only 23 patients (8%) who underwent complete FFR-guided revascularization died or had a nonfatal myocardial infarction, cerebrovascular event, or repeat revascularization within a year of treatment, compared with 121 (20.5%) patients who underwent infarct-only treatment (hazard ratio, 0.35; 95% confidence interval, 0.22-0.55; P less than .001), Pieter C. Smits, MD, PhD, reported during a late-breaker session at the annual meeting of the American College of Cardiology.

Most of the difference in this combined primary endpoint stemmed from a markedly lower rate of repeat PCI (6% vs. 17.5%; P less than .001) after complete revascularization, Dr. Smits said. But FFR-guided complete revascularization also led to a significantly lower rate of hospitalizations for heart failure, unstable angina, or chest pain, he his associates reported in an article published simultaneously online March 18 in the New England Journal of Medicine (2017. doi: 10.1056/NEJMoa1701067 ).

Importantly, coronary angiography overestimated the physiological significance of noninfart lesions in the study, the researchers wrote. About half of noninfarct lesions that were considered significant on angiography had FFR values above 0.80, meaning that they were not physiologically significant.

Some 50% of patients with acute ST-segment elevation myocardial infarction (STEMI) have severe stenotic lesions of noninfarct coronary arteries. These lesions often are managed conservatively, but two recent randomized trials have challenged this approach, tying preventive stent placement to lower rates of subsequent adverse events. However, both studies based the decision to use stents on angiographic appearance, not symptoms or ischemia, even though angiography can fail to accurately estimate the functional severity of a lesion, the investigators wrote. For stable patients, using FFR to guide revascularization instead can prevent adverse events compared with angiography or conservative management, they added.

To more rigorously compare FFR-guided revascularization of noninfarct coronary arteries with infarct-only treatment, the researchers randomly assigned 885 adults with acute STEMI and multivessel disease to one of these two approaches during primary PCI. A total of 295 patients underwent FFR-guided complete revascularization, and 590 underwent infarct-only treatment plus FFR evaluation of noninfarct-artery lesions.

Compared with infarct-only treatment, complete revascularization was associated with lower, but statistically similar, rates of mortality (1.7% vs. 1.4%; HR, 0.80; 95% CI, 0.25-2.6; P = .7), nonfatal myocardial infarction (4.7% vs. 2.4%; HR, 0.5; 95% CI, 0.2-1.1; P = .1), and cerebrovascular events (0.7% vs. 0%). The study lacked power to detect differences in rates of these uncommon events, the researchers noted.

In the infarct-only treatment group, stable or unstable angina accounted for most repeat revascularizations, about 80% of which were clinically indicated based on the study protocol, according to the researchers. Performing FFR-guided revascularization during primary PCI prevents sequential catheterizations and can potentially save costs by reducing predischarge stress tests, they commented. In their study, 12% of patients in the infarct-only group underwent stress tests, compared with 7% of those who underwent FFR-guided revascularization (P = .03).

Two patients experienced a serious adverse event related to FFR, the investigators noted. In one case, the FFR wire caused a dissection in the noninfarcted right coronary artery. The artery subsequently infarcted and the patient died in the hospital. Another patient developed an occlusion of the noninfarcted left anterior descending coronary artery. The patient developed ST-segment elevation and recurrent chest pain, but underwent successful PCI of the artery. There were no other adverse events except for brief episodes of atrioventricular conduction delay and episodes of moderate hypotension, they wrote.

This was an open-label study, and it is possible that patients and physicians in the infarct-only group were biased toward subsequent revascularizations because they knew the angiography results, the researchers also noted.

Maasstad Cardiovascular Research funded the study with unrestricted grants from Abbott Vascular and St. Jude Medical. Dr. Smits disclosed grant support from Abbott Vascular and St. Jude Medical, and grants support and personal fees from both entities outside the submitted work.

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