Ischemia and No Obstructive Coronary Artery Disease ( INOCA ): What Is the Risk?

Abstract

An increasing number of stable patients with evidence of ischemia but no obstructive coronary artery disease (CAD) at coronary angiography, now termed INOCA, are seen. Objective myocardial ischemia or limited coronary flow reserve (CFR) consistent with coronary microvascular dysfunction (CMD) are identified in most of these patients. Although these patients were previously thought to be at low risk for major adverse cardiovascular events (MACE) and were provided only reassurance, newer data document that stable INOCA patients are a heterogeneous population with an elevated MACE risk. Primary prevention cardiovascular risk scores for asymptomatic populations may underestimate risk in these patients, while secondary prevention risk scores developed in patients with established cardiovascular disease may overestimate risk. Medical therapies may be underutilized when no obstructive CAD is documented, and patients are commonly discharged from specialty practice. We review the existing knowledge regarding observed and predicted risk using available risk scores in stable INOCA patients to identify knowledge gaps and plan investigation needed to develop evidence‐based guidelines for this growing patient population.