Understanding Patient Characteristics and Coronary Microvasculature: Early Insights from the Coronary Microvascular Disease Registry.

Coronary angiography has limitations in accurately assessing the coronary microcirculation. A new comprehensive invasive hemodynamic assessment method utilizing coronary flow reserve (CFR) and the index of microvascular resistance (IMR) offers improved diagnostic capabilities. This study aimed to present early real-world experience with invasive hemodynamic assessment of the coronary microvasculature in symptomatic patients with nonobstructive coronary artery disease (CAD) from the Coronary Microvascular Disease Registry, which is a prospective, multi-center registry that standardized the evaluation of patients with angina and nonobstructive CAD who underwent invasive hemodynamic assessment of the coronary microvasculature using the Coroventis CoroFlow Cardiovascular System. All patients underwent comprehensive invasive hemodynamic assessment. Analysis was performed on the first 154 patients enrolled in the Coronary Microvascular Disease Registry; their mean age was 62.4 years and 65.6% were female. A notable proportion of patients (31.8%) presented with a Canadian Cardiovascular Society Angina Score of 3 or 4. Coronary microvascular dysfunction was diagnosed in 39 of 154 patients (25.3%), with mean fractional flow reserve of 0.89 ± 0.43, mean resting full cycle ratio of 0.93 ± 0.08, mean CFR of 1.8 ± 0.9, and mean IMR of 36.26 ± 19.23. No in-hospital adverse events were reported in the patients. This study demonstrates the potential of invasive hemodynamic assessment using CFR and IMR to accurately evaluate the coronary microvasculature in patients with nonobstructive CAD. These findings have important implications for improving the diagnosis and management of coronary microvascular dysfunction, leading to more targeted and effective therapies for patients with microvascular angina.