Association of native T1 times with biventricular function and hemodynamics in precapillary pulmonary hypertension

In precapillary pulmonary hypertension (PH) patients, we sought to (1) investigate the relationship between ventricular insertion point (VIP) T1 times, hemodynamic parameters, and biventricular function, and (2) determine the predictors of anterior and inferior VIP T1 time. Twenty-two patients with precapillary PH underwent 1.5-T cardiac MR, right heart catheterization (RHC), and echocardiography. A group of 10 healthy age- and sex-matched volunteers served as controls. Biventricular function, morphology and mass were obtained from short-axis cine images. Native T1 times at anterior, inferior VIP, septum and LV lateral wall were respectively derived from all subjects. Mixed venous oxygen saturation (SvO₂) was the strongest hemodynamic parameters correlating with anterior (r_p = -0.67, P = 0.001) and inferior VIP T1 time (r_p = -0.81, P < 0.001). Elevated VIP T1 times were associated with reduced right ventricular (RV) ejection fraction, RV longitudinal and transverse motion, and increased RV end-diastolic and end-systolic volume index. LV diastolic function, quantified as mitral E velocity, was negatively correlated with anterior, inferior VIP (r_p = -0.55, P = 0.01) and septal T1 times (r_p = -0.50, P = 0.02), and positively correlated with RV systolic function and wall motion. In multivariate linear regression analyses, systolic eccentricity index (sEI) was the independent predictor of average VIPs T1 time (β= 0.47, P < 0.01), and remained significant correlation after adjustment of RHC and demographic parameters. In patients with precapillary PH, VIP T1 times are associated with biventricular function and hemodynamic parameters. Among all the parameters, sEI acts as a determinant of average VIPs T1 time.