Association between coronary microcirculatory resistance, left atrial strain and heart failure with preserved ejection fraction in patents with ischemia and non-obstructive coronary arteries (INOCA)

Abstract

Abstract Background Coronary microvascular dysfunction (CMD) plays an important role in the pathogenesis of ischemia and non-obstructive coronary arteries (MINOCA) and heart failure with preserved ejection fraction (HFpEF). Left atrial strain (LAS) evaluation by transthoracic echocardiography (TTE) was proposed as a new diagnostic method to assess left ventricular dysfunction and HFpEF. However, its implementation into the diagnostic workup of INOCA has never been evaluated. Purpose The primary objective of the study was to evaluate the frequency of HFpEF in patents with INOCA using LAS as a marker of left ventricular dysfunction. The secondary objective was to assess the association between coronary microcirculatory resistance, LAS and HFpEF. Methods MOSAIC-COR is a single-center, prospective, observational registry of patents with INOCA diagnosed with pressure wire-based comprehensive coronary physiology assessment and provocative test with acetylcholine. In the absence of significant coronary artery stenosis CFR and IMR was calculated in LAD using thermodilution to assess CMD. Serum levels of NT-proBNP and LAS indexes (LA reservoir strain, LA contraction strain, LA conduit strain) were calculated to diagnose HFpEF according to EACVI consensus document published in the year 2022. Results We assessed 63 patients with INOCA, 35% male. Median age was 67 years. Baseline clinical characteristics of the study group is presented in Table. Coronary microvascular dysfunction was diagnosed in 37 patents (59%) and HFpEF was diagnosed in 15 patents (24%) . Worse left atrium reservoir strain was connected with higher value of IMR (P < 0.001) and higher level of NT-proBNP (P < 0.001). Worse left atrium conduit strain was connected with higher value of IMR (P = 0.04). Left atrium contraction strain was connected with higher level of NT-proBNP (P < 0.001) (Figure). Conclusions Confirmation of HFpEF in 24% of INOCA opens new therapeutic option for this group of patents. Association between microvascular resistance and left atrium strain may reflect pathophysiological connection between INOCA and HFpEF. Implementation of SGLT-2 inhibitors in the treatment of CMD with and without INOCA require further evaluation.