Search

Summary This study aimed at assessing left ventricular (LV), left atrial (LA) and right ventricular (RV) volumes in patients before and after MitraClip™ implantation by cardiac magnetic resonance imaging (CMR). Background The MitraClip™ is a novel device for percutaneous mitral valve repair. Recent studies demonstrated a reduction of LV volumes after MitraClip™ implantation using echocardiography. CMR is currently the reference method to assess cardiac volumes but has not been used to assess LV remodeling after MitraClip™ implantation so far. Methods Twelve patients with functional (n=7) or degenerative (n=5) mitral valve regurgitation grade 3 to 4 underwent CMR at baseline (BL) before and at 6 month follow-up (FU) after successful MitraClip™ implantation. CMR protocol consisted of short- and long-axis slices using a steady-state-free-precession cine sequence for the assessment of LV, LA and RV volumes. Results Minor device-related artifacts were observed, enabling reliable delineation of endocardial borders in all patients at FU. Figure 1) demonstrates typical device-related artifacts 6 month after implantation (A) in comparison with a corresponding pre-implantation image (B). Mean intra- and inter-observer biases were 0.9±2.0 and 1.6 ±2.9 % for LV end-diastolic (LVEDV), 0.3±4.7 and 1.8 ±6.4 % for LV end systolic (LVESV), 0.1±2.9 and 2.2±3.7 % for RVEDV, 1.7±7.8 and 3.5±8.8 % for RVESV as well as 0.3±7.6 and 13.7±14.0 % for LA (LAV) volume indices at FU. No significant differences in intra- or inter-observer biases were observed between BL and FU. LVEDV (127 (96-150) vs. 112 (86-150) ml/m 2 ; p=0.03) as well as LVESV (82 (54-91) vs. 69 (48-99) ml/m 2 ; p=0.03) indices significantly decreased from BL to FU. No significant difference was found for RVEDV (94 (75103) vs. 99 (77-123) ml/m 2 ; p=0.91), RVESV (48 (42-80) vs. 51 (40-81) ml/m 2 ; p=0.48) and LAV (87 (55-124) vs. 92 (48-137) ml/m 2 ; p=0.20) indices between BL and FU.

Diastolic dysfunction was recently recognized as an important cause for heart failure in patients with preserved ejection fraction. Diastolic dysfunction is typically assessed in clinical routine using transmitral and pulmonary-venous flow characteristics by Doppler-echocardiography. We hypothesized that VENC-MRI has a similar ability to identify patients with diastolic dysfunction compared to Doppler-echocardiography.

The presence of reduced LAA flow velocities indicates patients who are prone to thrombus formation in the LAA and therefore being at high risk for subsequent cardioembolic stroke. LAA flow velocities are typically assessed by TEE in clinical routine. VENC-MRI is an established tool for the quantification of transvalvular flow, but the feasibility of LAA flow measurements by VENC-MRI has not been studied so far.