Cardiac Remodeling Following Percutaneous Mitral Valve Repair – Initial Results Assessed by Cardiovascular Magnetic Resonance Imaging

Extent and determinants of left ventricular reverse remodeling in patients with secondary mitral regurgitation undergoing MitraClip implantation

Background

In secondary MR, data on left ventricular (LV) remodeling after MitraClip procedure are rare, even this information may impact patient selection. This study investigated changes in LV structure and function by cardiovascular magnetic resonance (CMR) following MitraClip implantation for secondary mitral regurgitation (MR) in order to assess extent and predictors of LV reverse remodeling (LVRR).

Methods and Results

Twenty-nine patients underwent CMR imaging prior to and six months after MitraClip procedure. LVRR was defined by a decrease of LV end-diastolic volume index (LVEDVi) > 15% compared to baseline. According to the definition of LVRR, 34% of patients displayed LVRR at follow-up CMR. Baseline LV stroke volume index (LVSVi), LV ejection fraction (LVEF), LV circumferential strain and MR volume at baseline were predictors of LVRR at follow-up. At second CMR, we detected an improvement in hemodynamic status as illustrated by an increase in effective LVSVi (28 ± 8 ml/m² vs. 33 ± 8 ml/m²; p = 0.053) and cardiac index (2.0 ± 0.5 vs. 2.3 ± 0.5 l/min; p = 0.016), while LVEF and LV strain parameters did not change (p > 0.05). Improvements in effective LVSVi were associated with the decrease of MR volume (r = 0.509; p = 0.018) and MR fraction (r = 0.629; p = 0.002) by MitraClip.

Conclusions

Together, MitraClip implantation is associated with LVRR in one third of patients. Baseline LV function and magnitude of MR are important predictors of LVRR. Improvement of hemodynamic status may be assessed by effective stroke volume index and correlates with the reduction of MR by MitraClip implantation, rather than an increase in LV contractility.

Left atrial global function in chronic heart failure patients with functional mitral regurgitation after MitraClip

BACKGROUND

Left atrial (LA) volumes and function are believed to improve following interventional reduction of mitral regurgitation (MR) with MitraClip. However, exact LA alterations after MitraClip in patients with functional MR and functional mitral regurgitation (FMR) are unknown.

OBJECTIVES

We aimed to evaluate the effect of MitraClip on LA volumes and global function in patients with FMR and its importance for patients' prognosis.

METHODS

All patients underwent three-dimensionally transthoracic echocardiography with an offline evaluation of LA geometry and strain analysis at baseline and follow-up (FU). FU examinations were planned for 6 and 12 months after MitraClip.

RESULTS

We prospectively included 50 consecutive surgical high-risk (logistic EuroSCORE: 17.2 ± 13.9%) patients (77 ± 9 years, 22% female) with symptomatic moderate-to-severe to severe functional MR without atrial fibrillation. Echocardiographic evaluation showed that the E/E' ratio was significantly higher at FU (15.6 ± 7.3, 24.1 ± 13.2, p = .05) without relevant changes in systolic left ventricle (LV) function (p = .5). LA volumes (end-diastolic volume [LA-EDV] and end-systolic volume [LA-ESV]) (LA-EDV: 83.1 ± 39.5 ml, 115.1 ± 55.3 ml, p = .012; LA-ESV: 58.4 ± 33.4 ml, 80.1 ± 43.9 ml, p = .031), muscular mass (105.1 ± 49.3 g, 145.4 ± 70.6 g, p = .013), as well as LA stroke volume (24.6 ± 12.5 ml, 34.9 ± 19.1 ml, p = .016) significantly increased after the procedure. LA ejection fraction (LA-EF: 31.7 ± 12.8%, 31.1 ± 12.3%, p = .8) and atrial global strain (aGS: -10.8 ± 5.4%, -9.7 ± 4.45%, p = .4) showed no significant changes at FU. Despite no relevant changes during FU, the baseline aGS was found to be the strongest predictor for mortality and adverse interventional outcome.

CONCLUSION

MitraClip increases atrial stroke volume, atrial volumes, and muscular mass in patients with FMR. We found that the baseline aGS the strongest predictor for mortality, rehospitalization, and higher residual MR at FU.