Assessment of acute changes in ventricular volumes, function, and strain after interventional edge-to-edge repair of mitral regurgitation using cardiac magnetic resonance imaging.

Abstract

Whereas haemodynamic and echocardiographic studies suggest benefits for left ventricular (LV) function and cardiac output following reduction in LV preload by interventional edge-to-edge repair for mitral regurgitation (MR), there is limited data on volumetric and functional LV and right ventricular (RV) changes using cardiac magnetic resonance (CMR) imaging. Patients with moderate to severe MR and high surgical risk underwent MitraClip-implantation and CMR imaging before and within 7 days after the procedure. In addition to volumetric and flow studies, myocardial feature tracking (FT) technology for quantification of myocardial strain was applied. Twenty patients (age: 76 ± 8 years) with functional (n = 15) or degenerative MR (n = 5) with a mean logistic Euroscore I of 33 ± 16 underwent both successful MitraClip implantation and CMR imaging. MR fraction (36 ± 10 vs. 19 ± 12%; P < 0.001) and LV end-diastolic volume (115 ± 36 vs. 105 ± 41 mL/m2; P = 0.002) decreased significantly, whereas LV ejection fraction (42 ± 15 vs. 41 ± 16%, P = 0.8) and cardiac index (1.7 ± 0.5 vs. 1.8 ± 0.4 L/min/m2, P = 0.4) remained unchanged. MitraClip implantation resulted in a significant impairment of circumferential (-12.8 ± 4.8 vs. -8.2 ± 3.3; P = 0.002) and radial strain (15.4 ± 7.7 vs. 9.6 ± 5.3; P = 0.02) on basal short-axis view. On RV level, there were no significant changes in end-diastolic volume (83 ± 19 vs. 84 ± 18 mL/m2, P = 0.8), ejection fraction (42 ± 9 vs. 43 ± 11%, P = 0.8), or tricuspid regurgitation fraction (24 ± 17 vs. 25 ± 19%, P = 0.7). MitraClip implantation led to a significant improvement in New York Heart Association functional class (patients in functional class III-IV pre 100% vs. post 45%; P < 0.001). In severely compromised patients, marked reduction in MR by MitraClip implantation might not result in immediate improved cardiac output and effective biventricular forward flow.