Targeted medical treatment based on specific endotype defined by intracoronary physiology testing leads to rapid improvement of quality of life in symptomatic patients with INOCA

Abstract Introduction Ischemia with non-obstructed coronary arteries (INOCA) is a common but under-treated condition due to limited diagnostic methods and complex pathophysiologic mechanisms involving microvascular (MVA) and vasospastic angina (VSA), which both require tailored medical therapy. Purpose To prove the crucial role of intracoronary physiology testing to determine an exact INOCA endotype, adjust specific medical therapy and achieve improvement of quality of life in symptomatic patients with INOCA. Methods In the single centre study invasive testing was performed in 35 patients presented with cardiac symptoms, significant ischemia on non-invasive tests and non-obstructed epicardial coronary arteries during invasive or computed tomography coronary angiography (epicardial stenosis less than 50% and/or fractional flow reserve 0.80). MVA was defined as coronary flow reserve ≤ 2.5 and microvascular resistance index ≥ 25. The VSA was assessed if significant vasospasm (90%) with subsequent ischemic signs in ECG and chest pain was present during acetylcholine provocation test. Medical treatment was adjusted according to the European Society of Cardiology Guidelines and compared before and after invasive testing. Patients’ quality of life was assessed by Seattle Angina Questionnaire 7 (SAQ-7) before and 3 months after treatment adjustment. Results Invasive functional testing was performed in 35 patients. 19 (54.3%) patients were diagnosed with MVA, 9 (25.7%) with VSA, the combination of MVA and VSA was observed in 3 (8.6%) cases. In 4 patients (11.4%) the cause of symptoms was non-cardiac. Comparing medical treatment before and after invasive physiology testing - in patients with MVA significant increase in prescription of calcium channel blockers (CCB) (26.3% vs 94.7%, p0.001), antianginal treatment like ranolazine or trimetazidine (15.8% vs 94.7%, p0.001) and beta-blockers (BB) (42.1% vs 73.7%, p=0.05) was observed. In contrast, in patients with VSA the prescription of BB decreased by 66.6% (p=0.015) but increased the usage of CCB (44.4% vs 100%, p=0.03) and long-acting nitrates (0% vs 77.8%, p=0.002). There were no changes in prescribed treatment of patients with mixed INOCA endotype. Medical treatment adjustment according to the INOCA endotype resulted in an improvement in the SAQ-7 physical limitation (p0.001), angina frequency (p0.001), quality of life (p0.001) and summary score at 3 months (p0.001). There were no complications during the testing. Conclusion The intracoronary physiology testing is safe, and provides precise diagnosis in patients whose symptoms were previously attributed to non-cardiac causes, allowing to start early treatment suitable for exact INOCA endotype, which leads to a rapid improvement in patients quality of life.