MitraClip Treatment of Secondary Mitral Regurgitation in Heart Failure with Reduced Ejection Fraction: Lessons and Implications from Trials and Registries

Impact of extra-mitral valve cardiac involvement in patients with primary mitral regurgitation undergoing transcatheter edge-to-edge repair

BACKGROUND

In the context of primary mitral regurgitation (PMR), the selection of patients for transcatheter edge-to-edge repair (TEER) does not include a systematic assessment of PMR-associated cardiac remodelling.

AIMS

We aimed to investigate the epidemiology and prognostic significance of different phenotypes of extra-mitral valve (MV) cardiac involvement in a large series of patients with PMR referred for TEER.

METHODS

The study included 654 patients from the multicentre Italian GIOTTO registry, stratified into groups according to extra-mitral valve (MV) cardiac involvement. The primary endpoint was all-cause death at 2-year follow-up.

RESULTS

Patients with no cardiac involvement (NI; n=58), left heart involvement (LHI; n=343) and right heart involvement (RHI; n=253) were analysed. Acute technical success was achieved in 98% of patients. Kaplan-Meier curve analysis revealed significantly worse survival in patients with LHI and RHI (p=0.041). On multivariate Cox regression analysis, extra-MV cardiac involvement, haemoglobin level and technical success were independent predictors of the primary endpoint occurrence.

CONCLUSIONS

Grading cardiac involvement may help refine risk stratification, since at least 1 group of extra-MV cardiac involvement represents in itself a negative predictor of midterm outcome.

Effect of Chronic Kidney Disease on 5-Year Outcome in Patients With Heart Failure and Secondary Mitral Regurgitation Undergoing Percutaneous MitraClip Insertion

Chronic kidney disease (CKD) is strongly related to outcomes in cardiovascular diseases. Limited data are available regarding the independent prognostic role of CKD after transcatheter mitral valve repair with MitraClip. We sought to evaluate the real impact of CKD in a large series of patients with heart failure (HF) and secondary mitral regurgitation (SMR) who underwent MitraClip treatment. The study included 565 patients with severe SMR from a multicenter international registry. Patients were stratified into 3 groups according to estimated glomerular filtration rate (eGFR) assessment before MitraClip implantation: normal eGFR (≥60 ml/min/1.73 m²) (n = 196), mild-to-moderate CKD (30 to 59 ml/min/1.73 m²) (n = 267), and severe CKD (<30 ml/min/1.73 m²) (n = 102). The primary end point was a composite of overall death and the first rehospitalization for HF, the secondary end points were overall death, cardiac death, and first rehospitalization for HF. CKD was present in about 2/3 of patients. At 5-year Kaplan-Meier analysis, primary clinical end point occurred in 60% of patients with normal eGFR, compared with 73% cases in patients with mild-to-moderate CKD and 91% in patients with severe CKD (p <0.001). Long-term overall death rate significantly decreased with increasing eGFR, and cardiac death and rehospitalization for HF rates. Multivariate Cox regression analysis identified severe CKD as the strongest independent predictor of adverse outcome (hazard ratio 2.136, 95% confidence interval 1.164 to 3.918, p = 0.014). In conclusion, CKD affected about 2/3 of patients who underwent MitraClip treatment for severe SMR, and it was a strong and independent predictor of 5-year adverse outcomes.

Prognostic Value of Pre-operative Atrial Fibrillation in Patients With Secondary Mitral Regurgitation Undergoing MitraClip Implantation

Limited data are available regarding the independent prognostic role of preoperative atrial fibrillation (AF) after transcatheter mitral valve repair with MitraClip. We sought to evaluate the impact of preoperative AF in patients with heart failure (HF) and concomitant secondary mitral regurgitation (MR) after MitraClip treatment. The study included 605 patients with significant secondary MR from a multicenter international registry. Patients were stratified into 2 groups according to the presence or absence of preoperative AF. Primary end point was 5-year overall death, secondary end points were 5-year cardiac death and first re-hospitalization for HF. To account for baseline differences, patients were propensity score matched 1:1. The overall prevalence of preoperative AF was 44%. At 5-year Kaplan-Meier analysis, compared with patients without AF, those with AF had significantly more adverse events in term of overall death (67% vs 43%; HR 1.84, log-rank p <0.001) and cardiac death (56% vs 29%; HR 2.11, log-rank p <0.001) and re-hospitalization for HF (63% vs 52%; HR 1.33, log-rank p = 0.048). Multivariate analysis identified AF as independent predictor of worse outcome in term of primary end point (HR 1.729, 95% C.I. 1.060 to 2.821; p = 0.028). After propensity score matching, patients with AF had higher rates of death and cardiac mortality but similar rates of re-hospitalization for HF. In conclusion, in patients with HF undergoing MitraClip treatment for secondary MR, preoperative AF is common and an unfavourable predictor of 5-year death and cardiac death. However, AF did not affect the frequency of re-hospitalization for HF.