Substudy results stratified by the aetiology of MR. (A) Prevalence, extent, and distribution of PVSFR stratified by the aetiology of MR. PVSFR appeared more frequently in right PVs compared with left PVs in all aetiologies. Bar graphs show the prevalence of the number of PVSFRs in each aetiology of MR. The horizontal axis shows the number of PVSFRs. In DMR, 77.8% patients did not have a matched distribution of PVSFR (1, 2, or 3) in individuals. In V-FMR, 60.0% patients had a matched distribution of PVSFR (0 or 4) in individuals. (B) Correlations of the number of PVSFRs with PCWP and 3D-VCA stratified by the aetiology of MR. DMR, degenerative MR; MR, mitral regurgitation ; PCWP, pulmonary capillary wedge pressure; PVSFR, pulmonary venous systolic flow reversal; V-FMR, ventricular functional MR; 3D-VCA, 3D vena contracta area.