Characterization of Left Ventricular Hemodynamic Forces in Mitral Regurgitation Using 4-Dimensional-Flow Magnetic Resonance Imaging

Background: Mitral regurgitation (MR) is one of the most common valvular heart diseases. Despite the recognized importance of hemodynamic force (HDF) in cardiology, its exploration in MR has been limited. Therefore, using a retrospective observational study design, we aimed to investigate the potential of noninvasively assessed systolic and diastolic HDF derived from 4-dimensional-flow magnetic resonance imaging (4D-flow MRI) as markers for determining MR. Method: The study cohort included 15 controls (19-61 years) and 26 MR patients (20 with primary and 6 cases with secondary MR, 33-75 years) classified into trivial-to-severe MR through cardiac MRI. The 3 T/4D-flow MRI sequence was used to assess left ventricular (LV) HDF (integral of intraventricular pressure gradients over the LV cavity) in 3 directions (lateral-septal, inferior-anterior, and apical-basal) using “Segment,” v2.2 R6410. Results: A negative coefficient for peak-systolic apical-basal HDF corresponded to decreased ejection fraction (β = −8.1, SE = 3.3, t = −2.5, P = .03), and a positive association was found between LV mass index and peak-systolic apical-basal HDF (β = 25.6, SE = 11.1, t = 2.3, P = .04). Peak-systolic apical-basal and E-wave apical-basal (diastolic HDF at E-wave time point) HDF emerged as significant predictors in detecting severe MR (Estimate = 2.2, P = .007; Estimate = 1.8, P = .015, respectively). The peak-systolic apical-basal HDF was also notably correlated with age in moderate-severe MR ( r = 0.88, P = .022). Conclusion: Mitral regurgitation affects early diastolic filling and peak systolic ejection, indicated by peak-systolic and E-wave HDF in the apical-basal direction, offering insights into dynamic flow patterns and LV remodeling. Hemodynamic force analysis could enhance risk stratification and guide therapeutic decisions, complementing traditional diagnostic methods for improved MR management.