P18 PROGNOSTIC IMPACT OF MITRAL REGURGITATION BEFORE AND AFTER TRANSCATHETER AORTIC VALVE REPLACEMENT IN PATIENTS WITH SEVERE LOW FLOW, LOW GRADIENT AORTIC STENOSIS

Abstract 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.