Impact of aortic valve replacement for severe aortic stenosis on organic and functional mitral regurgitation

Aims: Concurrent mitral regurgitation (MR) influences treatment considerations in patients with severe aortic stenosis (sAS). Limited information exists regarding haemodynamic effects of sAS on MR severity and outcome of these patients. We assessed the impact of aortic valve replacement (AVR) on MR according to mechanism in patients with sAS and MR. Methods and results: In patients with sAS who received surgical or transcatheter AVR from 2008 to 2017, those with effective mitral regurgitant orifice area (ERO) ≥ 10 mm² prior to AVR were evaluated. The change in MR after AVR was considered significant when there was at least one grade difference. We compared the all-cause mortality of patients with and without improvement in MR. Of 234 patients with sAS and MR (age 80 ± 9 years, 52% male, ERO 19 ± 7 mm²), organic and functional MR were present in 166 (71%) and 68 (29%), respectively. MR improved in 136 (58%); improvement occurred with similar frequency in organic versus functional MR (59% and 57%, P = 0.88). Associated determinants were absence of atrial fibrillation in organic MR [odds ratio (OR) 2.09, 95% confidence interval (CI) 1.00–4.37; P = 0.049] and indexed aortic valve area (iAVA) ≤ 0.40 cm² in functional MR (OR 3.28, 95% CI 1.13–9.47; P = 0.028). In the overall cohort, mitral annulus diameter < 3 cm (OR 1.74, 95% CI 1.02–2.97; P = 0.041) and QRS duration < 115 ms (OR 1.73, 95% CI 1.00–2.98; P = 0.049) were independently associated with improvement in MR. During median follow-up of 3.5 years, lack of improvement in MR was not associated with higher mortality in the overall cohort of patients with ERO ≥ 20 mm² [adjusted hazard ratio (HR) 1.71, 95% CI 0.90–3.27; P = 0.10, adjusted for age, New York Heart Association III or IV, diabetes, and creatinine ≥ 2.0 mg/dL]. Lack of improvement in organic MR was associated with higher mortality (adjusted HR 3.36, 95% CI 1.40–8.05; P < 0.01). In patients with functional MR, change in MR was not associated with mortality (HR 1.24, 95% CI 0.44–3.47; P = 0.68). Conclusions: In nearly 60% of patients with sAS and MR, MR improved after AVR, even in the majority of patients with organic MR. Absence of atrial fibrillation in organic MR, iAVA ≤ 0.40 cm² in functional MR, and mitral annulus diameter < 3 cm and QRS duration < 115 ms in the overall population were associated with MR improvement. Post-operative improvement in organic MR was associated with better survival.