Patient selection for elective revascularization to reduce myocardial infarction and mortality: new lessons from randomized trials, coronary physiology, and statistics.

Abstract

As stated in American College of Cardiology/American Heart Association Guidelines, randomized trials have not demonstrated that elective percutaneous coronary intervention (PCI) reduces myocardial infarction (MI) or mortality over medical treatment. Even the Fractional Flow Reserve Guided PCI Versus Medical Therapy in Stable Coronary Disease (FAME 2) trial showed no statistically significant benefit of PCI over the deferred group by traditional intention-to-treat, nonbenchmark analysis starting at randomization that includes procedure-related events. Benchmark analysis in FAME 2 beginning 1 week after PCI removed procedure-related events that counterbalanced subsequent reduced MI and mortality compared with the deferred group. Meta-analysis of the literature on risk of events related to fractional flow reserve (FFR), including FFR Versus Angiography in Multivessel Evaluation (FAME), and other physiological measures of severity reveal an underappreciated, powerful interdependence among physiological severity of stenosis, diffuse coronary artery disease (CAD), event rates, sample size, and statistical certainty of differences. This analytic review synthesizes an evidenced-based, quantitative hypothesis and potential solution to this issue based on hard data from the literature by coauthors of diverse cardiovascular disciplines in trial design, biostatistics, invasive procedures, coronary physiology, fluid dynamics, coronary pathology, and quantitative imaging. Our synthesis elucidates a dual hypothesis for failure of elective PCI in stable CAD to reduce MI or mortality and novel trial design for selecting patients for whom PCI will likely reduce these events. First, a large burden of global diffuse CAD carries a high risk of coronary events unmitigated by PCI of a focal stenosis. Second, focal stenosis severity in previous randomized revascularization trials has been too modest without objectively quantified sufficient severity to observe benefit of PCI. In previous trials, mixture of diffuse coronary disease and intermediate stenosis may not incur high enough risk for potential benefit by PCI for sample size of reported trials. Greater quantitative severity with …