Significant mitral regurgitation in patients undergoing TAVR: Mechanisms and imaging variables associated with improvement

Background Significant mitral regurgitation (MR) is associated with poorer outcomes in patients undergoing transcatheter aortic valve replacement (TAVR). Factors associated with MR improvement have not been studied thoroughly. Methods Retrospective analysis of consecutive patients treated with TAVR with more than mild MR at baseline. MR evolution was assessed at 1-3 and 6-12 months after intervention. MR severity and mechanisms were assessed by echocardiography. Mitral annulus calcification (MAC) was quantified using preoperative cardiac CT. Results From 674 consecutive TAVR recipients, 78 with more than mild MR had a 6-12 months follow-up. Following TAVR, MR improved in 34 patients (43%), remained stable in 38 (49%) and worsened in 6 (8%). Patients with MR improvement had greater tenting area (141 +/- 56 vs. 99 +/- 40 mm(2), P < 0.01), tenting height (7.2 +/- 1.9 vs. 5.6 +/- 1.9 mm, P < 0.01) and lower ejection fraction (43 +/- 16 vs. 52 +/- 14%, P = 0.01). MAC was frequent (87.7% of patients) and a trend in greater MAC was observed in patients without MR improvement (3560 +/- 5587 vs. 2053 +/- 2800, P = 0.16). In multivariable analysis, tenting area (OR per 10 mm(2) increase: 1.012, 95% CI, 1.001-1.024 P = 0.039) and annulus calcifications associated with leaflet restriction (OR = 0.108, 95% CI, 0.012-0.956, P = 0.045) were independently associated with MR outcome after TAVR. Conclusion Larger mitral valve tenting area was associated with more improvement of MR after TAVR whereas extensive MAC associated with leaflet restriction was associated with less improvement. This may help in the clinical decision-making process of TAVR candidates with concomitant MR.