Mitral valve regurgitation in patients undergoing TAVI: Impact of severity and etiology on clinical outcome

Background: Mitral regurgitation (MR) is frequently associated with severe aortic stenosis, but its influence on outcomes after transcatheter aortic valve implantation (TAVI) remains controversial. This study sought to assess the baseline etiology and degree of MR in TAVI population, identify the predictors of MR changes and investigate the clinical and prognostic impact of baseline MR at mid and long-term follow-up. Methods: We enrolled 572 consecutive patients who underwent TAVI. MR degree and etiology were evaluated by echocardiography at baseline and 1-year follow-up. Clinical outcomes were obtained up to 3-year follow-up. Results: At baseline, 168 patients (29%) had moderate-to-severe MR (MR ≥ 2). Organic MR was more frequently associated with MR ≥ 2 (MR < 2: 20%, MR ≥ 2: 43%, p < 0.001). Relevant MR had improved more in functional MR (79%) compared to organic MR (50%, p = 0.001). At the multivariate analysis, the coexistence of coronary artery disease (p = 0.026), absence of atrial fibrillation (p = 0.038) and functional etiology (p = 0.025) were predictors of MR improvement after TAVI. Patients with baseline MR ≥ 2 had a higher mortality rate than those with MR < 2 at 1-year and 3-year follow-up. Moreover, a landmark analysis starting from 1-year to 3-year follow-up, demonstrated that organic MR was associated with an increased risk of mortality throughout 3-year follow-up compared with functional MR, irrespective of MR severity. Conclusions: Baseline MR ≥ 2 in TAVI patients was associated with early and late mortality rate. At 1-year, significant improvement in MR severity was observed mainly in patients with functional MR ≥ 2. Organic MR ≥ 2 had a negative impact on 3-year, but not 1-year, mortality rate.