Linking Coronary Microvascular and Cardiac Diastolic Dysfunction in Diabetes: Are Women More Vulnerable?

Abstract

Accumulating evidence has demonstrated a clear association of coronary microvascular dysfunction with poor cardiac outcomes (1–4). For example, in patients with normal myocardial perfusion imaging, coronary microvascular dysfunction is a powerful predictor of major adverse cardiac events and improves risk discrimination in clinical risk models (1). Furthermore, these studies suggest that coronary microvascular dysfunction may underlie the increased cardiac risk associated with some comorbid conditions. Particularly, in patients with diabetes, the presence of coronary microvascular dysfunction effectively accounted for all of the increased cardiac mortality compared with patients with diabetes with no coronary microvascular dysfunction (5). Whether sex differences exist with regard to coronary dysfunction and outcomes in patients with diabetes has not been addressed; however, it is critically needed given the impact of diabetes to abrogate the cardiovascular protection afforded by female sex hormones (6). Coronary microvascular dysfunction is defined clinically as a coronary flow reserve (CFR) (ratio of resting to maximal hyperemic coronary blood flow) <2 in the absence of obstructive coronary artery disease (CAD) (4). Previous work has revealed important sex-specific relationships between coronary dysfunction and ultimate outcomes in broad patient populations referred for angiography (1,3). Namely, prospective examination revealed that symptomatic intermediate-to-high–risk women, but not men, with impaired CFR experience increased cardiovascular events (3). This has been attributed largely to the underlying cause of impaired CFR in women …