Invasive Coronary Physiology Assessment and Predictors of Coronary Microvascular Dysfunction in Patients with Diabetes Mellitus

Background Diabetes mellitus (DM) has been associated with coronary microvascular dysfunction (CMD) in previous non-invasive studies. However, invasive studies have shown conflicting results. Methods To evaluate the prevalence and predictors of CMD in diabetic patients, invasive coronary physiology data of patients with fractional flow reserve (FFR) > 0.80 on the target vessel were analyzed from the BELmicro registry. Coronary flow reserve (CFR) < 2.5 and index of microcirculatory resistance (IMR) ≥ 25 were considered abnormal. Results Out of 402 patients, 72 had DM. Diabetic patients were older [69(61, 75) vs 64(58, 73), p = 0.02] and had higher rates of hypertension (73 % vs 56 %, p = 0.009) and dyslipidemia (89 % vs 64 %, p < 0.001) compared to non-diabetics. No differences were found between diabetic and non-diabetic patients in FFR [0.92(0.89, 0.94) vs 0.91(0.88, 0.94), p = 0.8] and CFR [3.0(2.1, 4.4) vs 2.8(2.0, 4.1), p = 0.4]. IMR was slightly lower in diabetics [16(9, 24) vs 18(12, 27), p = 0.04], but the rate of abnormal IMR was comparable to non-diabetics (23 % vs 31 %, p = 0.2). Prevalence of CMD was similar between diabetics and non-diabetics (46 % vs 48 %, p = 0.8). Rates of CMD were comparable between patients with longstanding DM (≥10 years) and recent diagnosis (52 % vs 35 %, p = 0.2). No association was found between glycated hemoglobin levels and CFR and IMR. Female sex was the only independent predictor of CMD in diabetics (OR: 2.71, 95 % CI: 1.02, 7.50, p = 0.049). Conclusions No differences in prevalence of CMD were found between diabetic and non-diabetic patients. Longstanding diabetes, glycemic control and concomitant cardiovascular risk factors were not associated with CMD in diabetic patients.