PHILADELPHIA – The eagerly awaited results of the ISCHEMIA trial – the largest-ever randomized trial of an initial invasive versus conservative management strategy for patients with stable ischemic heart disease – were emphatically declared practice-changing by interventional cardiologists and noninterventionalists alike at the American Heart Association scientific sessions.
At a median 3.3 years of follow-up of 5,179 participants with baseline moderate or severe ischemia at 320 sites in 37 countries in ISCHEMIA (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches), an initial invasive strategy accompanied by optimal medical therapy (OMT) didn’t reduce the risk of the primary composite endpoint of cardiovascular death, MI, hospitalization for unstable angina, heart failure, or resuscitated cardiac arrest, compared with a conservative strategy of OMT alone. The rates at 4 years were 15.5% with the conservative strategy and 13.3% with the invasive strategy, reported study chair Judith S. Hochman, MD, professor of medicine and senior associate dean for clinical sciences at New York University.
Nor was there a significant between-group difference in the major secondary endpoint of cardiovascular death or MI: 13.9% with the conservative strategy, 11.7% with invasive management.
“The probability of at least a 10% benefit of the invasive strategy on all-cause mortality was less than 10%, based on a prespecified Bayesian analysis,” she added.
Prior to enrollment and randomization, CT angiography was routinely performed to rule out left main coronary artery disease.
Fifty-four percent of participants in the National Heart, Lung, and Blood Institute–funded trial had severe ischemia on a baseline noninvasive stress test. To the investigators’ surprise, patients with more severe ischemia or more extensive multivessel involvement didn’t do better with the invasive approach.
Almost a quarter (23%) of patients in the conservative management group crossed over to revascularization within 4 years.
An invasive strategy did result in significantly greater improvement in angina control and quality of life, as measured using the Seattle Angina Questionnaire, than OMT alone in patients who had angina at least once a month at baseline.
“We have 100% confidence that there is a treatment benefit associated with an invasive approach early as well as late after randomization,” said John A. Spertus, MD, coprincipal investigator for the ISCHEMIA quality of life analysis.
Indeed, he calculated that, for patients with weekly angina, the number needed to treat with revascularization instead of OMT alone for one to be angina-free at 3 months was three.
However, in the 35% of ISCHEMIA participants who reported no angina within the past month at baseline, the invasive strategy offered no quality of life advantage, he added.
“I really think we need to hit ‘pause’ on asymptomatic revascularization. I just don’t see any benefit in patients without symptoms, left main disease excluded,” commented Dr. Spertus, director of health outcomes research at St. Luke’s Mid-America Heart Institute and professor of medicine at the University of Missouri, Kansas City.