Background and aim of the study: Mitral regurgitation (MR) is frequently present in patients with calcific aortic stenosis (AS). Yet, the issue of whether to surgically correct the MR during aortic valve replacement (AVR) remains uncertain. The study aim was to define the outcome of MR after transcatheter aortic valve implantation (TAVI) in the TRanscatheter EndoVascular Implantation of VALves (REVIVAL) II trial.
Methods: Echocardiography was performed before and at 24 h, and three and six months after valve implantation. The degree of MR was evaluated by expert readers and by the vena contracta (VC) method. Significant MR was defined as at least mild to moderate MR. Those patients with a 30% reduction in VC were classified as good responders (GR group), and the remainder as poor responders (PR group).
Results: The study comprised 35 subjects with at least mild to moderate MR before TAVI. The mean VC of the whole group declined from 0.5 +/- 0.2 cm initially to 0.32 +/- 0.2 cm and 0.38 +/- 0.2 cm at 24 h and three months, respectively (p < 0.05). At three months, 12 patients had > 30% VC reduction; these constituted the GR group, while the remainder constituted the PR group. The percentage of patients with mitral annular calcification with restriction (MACr), defined as calcification encroaching onto the leaflets and restricting leaflet motion, was significantly lower in the GR group compared to the PR group (17% versus 61%, respectively; p < 0.05). The remaining pre-specified parameters did not differ significantly between the GR and PR groups, including age, gender, mitral valve tethering height and area (6 +/- 2 mm versus 5 +/- 3 mm and 10 +/- 4 mm2 versus 13 +/- 9 and 10 +/- 4 mm2, respectively), change in the aortic valve area (336 +/- 130% versus 285 +/- 180%), change in mean systolic aortic valve pressure (-20 +/- 8% versus - 23 +/- 10%), and left ventricular ejection fraction (47 +/- 15% versus 45 +/- 18%).
Conclusion: MR is improved significantly after TAVI for AS. MACr was the only variable associated with a reduction in MR improvement. These results suggest that a careful echocardiographic evaluation of the mitral valve prior to TAVI may help to predict which patients should experience an improvement in their MR.