Influences of Mitral Annuloplasty on Left Ventricular Flow Dynamics Assessed with 4D flow MRI

Structured Abstract Objectives We assessed the influence of annuloplasty procedures in mitral repair on left ventricular (LV) vortex flow patterns and aortic outflow patterns, and flow energy loss (EL). Methods Twenty healthy volunteers and 14 patients who had undergone mitral valve repair were examined using three-dimensional cine phase-contrast magnetic resonance imaging (4D flow MRI). A band group included seven patients with semi-rigid and two with flexible partial bands. The ring group included five patients with semi-rigid complete rings. LV vortex flow patterns, aortic outflow patterns, EL, and aortic annulus changes during one cardiac cycle were evaluated. Results Mitral repair induced different vortex flow patterns compared with that of healthy volunteers. The vortex beneath the anterior mitral leaflet with semi-rigid devices was double-stranded in early diastole, and it was single-stranded with flexible bands with a large shift toward the apex during diastole. Left ventricular EL (LVEL) in patients who underwent mitral repair (0.84 ± 0.42 mW) was higher than that in healthy volunteers (0.47 ± 0.10 mW). Complete rings disturbed aortic outflow patterns, with EL distribution changes. Smaller devices relative to patient body size disturbed LV flow patterns and caused high EL. No significant relationship was found between indexed ring orifice area (IROA) and transmitral mean pressure gradient (mPG) (r=-0.25, P=0.414), but a negative relationship exists between IROA and LVEL (r=-0.84, P Conclusions Mitral repair, especially with relatively small annuloplasty rings, induced abnormal LV flow patterns and EL elevation, which have the potential to be a novel hemodynamic evaluation method after mitral repair.