Microvascular dysfunction associated with reduced nailfold capillary density in patients with ischemia with no obstructive coronary artery disease

Funding Acknowledgements None. Introduction The impairment of microvascular function present in coronary microcirculation with chronic angina without obstructive coronary arteries. There are insufficient data in the literature regarding possible generalized microangiopathy in this population. Aim The aim of this study is to demonstrate whether patients with Angina with No Obstructive Coronary Artery Disease (ANOCA) compared to individuals without coronary microvascular dysfunction (CMD) are characterized by a different level of nailfold capillaroscopy abnormalities. Methods We examined 18 participants without CMD - non-CMD group [9 female, 50%, mean age: 54.4±8.1 years) and 26 patients with ANOCA - CMD group (22 female, 84,6%, mean age : 53.2±10.7 years). Functional coronary angiography was performed for the assessment of coronary microcirculation in all patients. Coronary flow reserve (CFR) and index of microvascular resistance (IMR) were measured in the left anterior descending coronary artery using a temperature/pressure sensor-tipped guidewire. In addition, the assessment of skin microcirculation was performed by capillaroscopy, a non-invasive technique to evaluate small vessels of the microcirculation in the nailfold, using stereomicroscope in all patients. Results In CMD group, mean CFR and IMR were 1.34±0.6 and 44.8±28, respectively. Out of the 26 MVD patients with abnormal CFR, 7 of them (27%) had a normal value of IMR, indicating functional microvascular dysfunction. On the other hand, 18 patients (69%) had an abnormal IMR, indicating structural microvascular dysfunction. Capillary density in patients with MVD was significantly decreased compared to the control group (7.6±2.2 vs 10.9±1.8 vessels/mm, p=0.04). The difference in capillary density between the two groups was statistically significant after adjustment for multiple comparisons (p<0.05). No significant difference was found in body mass index, renal function, medical history of dyslipidemia, diabetes mellitus and smoking status between the two groups (p<0.05). Conclusion Nailfold capillary density was reduced in ANOCA patients compared to control group. These data may provide new insights regarding possible generalized microangiopathy in CMD patients. These results suggest that there is an association between microcirculatory impairment at both heart and peripheral vascular bed level.