Background: There is little evidence about the prognostic role of mitral regurgitation (MR) in patients with low flow, low gradient aortic stenosis (LFLG-AS) undergoing transcatheter aortic valve replacement (TAVR).
Aims: The aim of this study was to assess the prevalence and outcome implication of moderately severe to severe MR in patients with LFLG-AS before and after TAVR.
Methods: This study included consecutive patients with LFLG-AS undergoing TAVR at two Italian high-volume centres. The study population was categorized according to the baseline MR severity and to the presence of MR improvement at discharge. The primary outcome was the composite of all-cause death and hospitalization for worsening heart failure (HF) up to one year. The secondary outcomes were the single components of the primary outcome.
Results: The study included 268 patients; 57 (21%) patients showed MR>2+. Patients with MR>2+ showed a lower one-year survival free from the primary outcome (Log-Rank <0.001; Figure1), all-cause death (Log-Rank <0.001), and HF hospitalization (Log-Rank <0.001) compared to patients with MR≤2+. At multivariable analysis, baseline MR>2+ was an independent predictor of the primary outcome (p<0.001). Among patients with baseline MR>2+, MR improvement was reported in 24 (44%) cases after TAVR. The one-year survival free from the primary outcome was significantly higher in patients with MR improvement than in those without (Log-Rank = 0.009), and both groups had a significantly lower survival free from the primary outcome when compared with patients with baseline MR <2+ (Figure 2). One-year survival free from the all-cause death (Log-Rank = 0.036) and HF hospitalization (Log-Rank = 0.005) was consistently higher in patients with MR improvement than in those without.
Conclusions: In this study, the presence of moderately severe to severe MR in LFLG-AS patients undergoing TAVR portend a worse clinical outcome at one year. TAVR may improve MR severity in nearly half of the patients, resulting in a potential outcome benefit after discharge.