Impact of clinical and hemodynamic factors on coronary flow reserve and invasive coronary flow capacity in non-obstructed coronary arteries - A patient level pooled analysis of the DEBATE and ILIAS studies.

AIMS: Coronary Flow Reserve (CFR) is a physiological index for the assessment of myocardial flow impairment due to focal or microcirculatory coronary artery disease (CAD). Coronary flow capacity (CFC) is another flow-based concept in diagnosing ischemic heart disease, based on hyperemic average peak velocity (hAPV) and CFR. We evaluated clinical and hemodynamic factors which potentially influence CFR and CFC in non-obstructed coronary arteries. METHODS AND RESULTS: Intracoronary Doppler flow velocity measurements to obtain CFR and CFC were performed after inducing hyperemia in 390 non-obstructed vessels of patients who were scheduled for elective percutaneous coronary intervention (PCI) of another vessel. Akaike's Information Criterion (AIC) revealed age, female gender, history of myocardial infarction, hypercholesterolemia, diastolic blood pressure, oral nitrates and rate pressure product as independent predictors of CFR and CFC. After regression analysis, age and female gender were associated with lower CFR and age was associated with worse CFC in angiographically non-obstructed vessels. CONCLUSIONS: Age and female gender are associated with lower CFR, and age with worse CFC in an angiographically non-obstructed coronary artery. CFC seems to be less sensitive to variations in clinical and hemodynamic parameters than CFR, and therefore is a promising tool in contemporary clinical decision making in the cardiac catheterization laboratory.