Two-year cardiac mortality after MitraClip treatment of functional mitral regurgitation in ischemic and non-ischemic dilated cardiomyopathy.

BACKGROUND

MitraClip implantation has evolved as a new tool for treatment of inoperable or high-risk patients with severe functional mitral regurgitation (FMR) due to dilated cardiomyopathy (DCM). Limited data are available regarding MitraClip outcomes comparing patients with ischemic and non-ischemic DCM.

METHODS

From 2008 to 2016, 314 patients received MitraClip for FMR at four institutions: Brescia, Zurich and Milan. Patients were stratified according to MR aetiology in non-ischemic FMR (n = 99) and ischemic FMR (n = 215). Preoperative risk factors, operative variables and outcomes up to 2-year were evaluated. A multivariable Cox Proportional Hazards survival model with covariate adjustments was used to assess the relationship between FMR aetiology and 2-year cardiac mortality.

RESULTS

As expected, patients with ischemic FMR had significantly more risk factors and comorbidities. Overall procedural success rate was 80% and in-hospital cardiac mortality was 3% without significant differences between aetiology. Two-year overall (25% vs. 19%, p = 0.574) and cardiac (18% vs. 16%, p = 0.990) mortality rates were comparable. No differences were detected in terms of re-hospitalization rates (32%), LVAD implantation (4.5%) and mitral valve surgery (1%). LVEF ≤ 25%, LVEDV > 216 ml, NT-proBNP ≥ 10.000 pg/ml and AF were the strongest baseline predictors of 2-year cardiac mortality. Greater improvements of 6MWT and NYHA functional class were observed in patients with non-ischemic FMR.

CONCLUSIONS

The ischemic or non-ischemic aetiology of DCM did not affect in-hospital and 2-year cardiac mortality after MitraClip in patients with FMR. In case of unfavorable baseline clinical condition, the indication for MitraClip should be carefully weighed in favour of conservative medical therapy alone or left ventricular assist device.