Ischemia With Non–obstructive Coronary Artery Disease (Inoca): A Single Centre Experience

Abstract Background Myocardial ischemia with non–obstructive coronary arteries (INOCA) is a chronic coronary syndrome condition that is associated with recurrent clinical presentations with chest pain, impaired functional capacity, reduced quality of life, myocardial infarction and heart failure. INOCA is usually under–diagnosed precisely. We report our experience for endotype characterization, tailored therapy and short term follow up. Methods Thirty–five patients presenting with clinical presentation of chronic ischemic heart disease requiring coronary angiography for diagnosis, who referred to our department between October 2022 and December 2023 were included. All patients with acute coronary syndrome (ACS), prior artery bypass grafting (CABG), presence of obstructive CAD (stenosis 70% or FFR 0.80), sever valvular heart disease and EF 40% were excluded. All patients were clinically evaluated and subjected to validated questionnaires to characterize angina and quality of life. Subsequently, functional coronary angiographic evaluation was carried out, through the bolus thermodilution method using adenosine, including a study of the fractional flow reserve (FFR), the determination of coronary flow reserve (CFR), and the index of microvascular resistance (IMR), specific for the microvascular district. Finally, acetylcholine test to evaluate the presence of any epicardial vasospasm. Based on the results of these evaluations, 4 endotypes can be identified: microvascular dysfunction (CMD), vasospastic angina (VSA), both CMD and VSA and non–cardiac chest pain. Results The majority of patients were female (63%), with hypertension (86%), hyperlipidemia (86%) and diabetes (23%). They presented with typical angina (87%) and half of them (60%) undergone provocative ischemia tests (76% tested positive). Following functional coronary angiographic evaluation, 57% patients had a diagnosis of INOCA, of these 30% microvascular dysfunction (CMD), 40% vasospastic angina (VSA), 30% both CMD and VSA. The acetylcholine test was performed in all patients, resulting positive in 14 out of 35 (40%). Each patient was prescribed a personalized therapy. Short term follow–up was performed with a general improvement in symptoms following optimized medical therapy. Conclusion INOCA is a heterogeneous nosological entity, underdiagnosed and often poorly treated. Invasive functional angiography is helpful to identify endotypes and appropriate therapy with a significant clinical benefit.