Left Ventricular Diastolic Function: Comparison of Slow Coronary Flow Phenomenon and Left Ventricular Hypertrophy in the Absence of Obstructive Coronary Disease.

Background An interplay of myocardial structural abnormalities and coronary arterial dysfunction underlies the worsening left ventricular compliance. The conventionally used angina drugs have demonstrated a beneficial effect on both angina and coronary flow in cases with microvascular dysfunction and non-obstructive coronary disease. Despite that, vasoactive therapy only partially affects diastolic function in this patient population. Purpose This retrospective study was planned to evaluate the association of myocardial mass, delayed epicardial coronary flow, and vasoactive drugs with parameters of diastolic function in two cohorts with preserved left ventricular function and non-obstructive coronary disease in patients with slow coronary flow phenomenon (SCFP) and patients with the hypertensive disease and left ventricular hypertrophy. Material and methods The epicardial coronary flow was evaluated in 48 patients with unstable angina in the absence of coronary stenosis >50%, by applying the methods of corrected thrombolysis in myocardial infraction frame count (cTFC). The abnormalities in the left ventricular function were assessed by echocardiography using PW-Doppler of the diastolic mitral inflow and tissue Doppler imaging. Twenty-one (43.8%) patients were diagnosed with SCFP, and twelve patients (25%) had slow epicardial coronary flow, hypertensive disease, and ventricular hypertrophy (SF). The remaining 15 (31.3%) were patients with ventricular hypertrophy, hypertension, and non-delayed epicardial coronary flow (NF). Results The patients with SF showed reduced peak early diastolic lateral mitral annular velocity (e') when compared to SCFP (7.1±1.9cm/s vs 8.6±2.1 cm/s, p=0.045) and NF (7.1±1.9 cm/s vs 8.7±1.8 cm/s, p=0.018). A borderline significant difference was observed for the peak early diastolic septal mitral annular velocity (e'S) between the patients with SF and SCFP ( 7.0±1.3 cm/s vs 8.3±2.1 cm/s, p=0.057). The ratio of mitral diastolic inflow velocity to early diastolic velocity of the mitral annulus (E/e') in the SF group was a tendency higher than E/e' of the patients with SCFP (9.8±3.1 vs. 8.2±2.1, p=0.084) and NF (9.8±3.1 vs. 7.8±1.5, p=0.051) .In the group with left ventricular hypertrophy, E/e' >10 was more frequently observed in patients with a marked delay in the epicardial flow (33.1 ± 13.1 frames vs. 25.4 ± 11.8 frames, p=0.011) and higher left ventricular mass (146.9 ± 17.7 g/m2 vs. 126.1 ± 121.5 g/m2, p=0.027). Conclusions Patients with microvascular angina represent a diverse population. The echocardiographic parameters of left ventricular relaxation (e') and end-diastolic pressure (E/e') are abnormally altered in the population with left ventricular hypertrophy compared to SCFP. The delayed epicardial flow further impairs diastolic function in hypertensive patients with hypertrophy and non-obstructive coronary disease.