Coronary Microvascular Function in Asymptomatic Middle-Aged Individuals with Cardiometabolic Risk Factors

Background In patients with ischemic heart disease, coronary microvascular dysfunction is associated with cardiovascular risk factors and poor prognosis; however, data from healthy individuals are scarce. Objectives The purpose of this study was to assess the impact of cardiovascular risk factors and subclinical atherosclerosis on coronary microvascular function in middle-aged asymptomatic individuals. Methods Myocardial perfusion was measured at rest and under stress using cardiac magnetic resonance in 453 individuals and used to generate myocardial blood flow (MBF) maps and calculate myocardial perfusion reserve (MPR). Subclinical atherosclerosis was assessed using 3-dimensional vascular ultrasound of the carotid and femoral arteries and coronary artery calcium scoring at baseline and at 3-year follow-up. Results Median participant age was 52.6 years (range: 48.9-55.8 years), and 84.5% were male. After adjusting for age and sex, rest MBF was directly associated with the number of the metabolic syndrome components present (elevated waist circumference, systolic and diastolic blood pressure, fasting glucose, and triglycerides and low high-density lipoprotein cholesterol), insulin resistance (homeostatic model assessment for insulin resistance), and presence of diabetes. MPR was reduced in the presence of several metabolic syndrome components, elevated homeostatic model assessment for insulin resistance, and diabetes. Stress MBF was inversely associated with coronary artery calcium presence and with global plaque burden. Higher stress MBF and MPR were associated with less atherosclerosis progression (increase in plaque volume) at 3 years. Conclusions In asymptomatic middle-aged individuals free of known cardiovascular disease, the presence of cardiometabolic risk factors and systemic (poly-vascular) subclinical atherosclerosis are associated with impaired coronary microvascular function. Better coronary microvascular function reduces atherosclerosis progression at follow-up. (Progression of Early Subclinical Atherosclerosis [PESA]; NCT01410318).