Influences of mitral annuloplasty on left ventricular flow dynamics assessed with 3-dimensional cine phase-contrast flow magnetic resonance imaging

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 3-dimensional cine phase-contrast magnetic resonance imaging. A band group included 7 patients with semi-rigid and 2 with flexible partial bands. The ring group included 5 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. LVEL in patients who underwent mitral repair (0.84 ± 0.42 mW) was greater 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 and transmitral mean pressure gradient (r = -0.25, P = .414), but a negative relationship exists between indexed ring orifice area and LVEL (r = -0.84, P < .001).

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.

Keywords: 3-dimensional cine phase-contrast magnetic resonance imaging; blood flow imaging; energy loss; hemodynamic; mitral annuloplasty; mitral repair.