Treatment trajectories and procedural outcomes of patients with significant mitral annular calcification and mitral valve disease

Background Mitral annular calcification (MAC) represents a growing challenge in patients with mitral valve disease (MVD), as complex anatomy and advanced age often limit surgical options. Mitral transcatheter edge-to-edge repair (M-TEER) is an established therapy for mitral regurgitation (MR), but extensive MAC may impair procedural outcomes. Transcatheter mitral valve replacement (TMVR) has emerged as an alternative providing predictable MR reduction. Purpose To characterize treatment pathways and compare procedural outcomes in patients with significant MAC and MVD. Methods Consecutive patients with significant MAC referred for TMVR screening were prospectively enrolled in a single-center registry. MAC severity was assessed using contrast-enhanced multi-slice computed tomography (MSCT). Patients were stratified by treatment strategy: TMVR with dedicated devices, M-TEER, or conservative management. Patients undergoing mitral valve surgery (n=2) were excluded. Baseline clinical, echocardiographic, and MSCT characteristics were analyzed. Short-term outcomes included technical success, post-procedural transmitral gradient, residual MR at discharge, and in-hospital mortality. Results Among 230 screened patients, 48 (21%) with significant MAC were included. TMVR was performed in 25% (n=12) and M-TEER in 23% (n=11), while 52% (n=25) received conservative management. TMVR patients were younger (median 75 years [IQR 66–80]) than those treated with M-TEER (81 years [80–84]) or conservatively (79 years [76–81]). Secondary MR predominated in the TMVR group (67%), whereas primary MR was more common in the M-TEER and conservative groups (55–60%). Baseline transmitral gradients were similar (median 4 mmHg). Left ventricular ejection fraction was lower in TMVR patients (mean 42.5%) compared with M-TEER (58%) and conservative management (55%). Moderate or greater mitral stenosis (52%) and severe circumferential MAC (60%) were most prevalent in conservatively managed patients. Both interventions achieved substantial MR reduction, with residual MR ≤ I+ at discharge in 92% after TMVR and 82% after M-TEER. In contrast, 92% of conservatively treated patients had persistent severe MR (IV+). Median post-procedural transmitral gradient was 3 mmHg after both interventions. Technical success was high (TMVR 91.7%, M-TEER 90.9%). One in-hospital death occurred after TMVR (8.3%); none after M-TEER or conservative management. Conclusion Patients with significant MAC and MVD represent a heterogeneous high-risk population with limited treatment options. Both TMVR and M-TEER showed high procedural success and effective MR reduction. However, over half remained unsuitable for intervention, particularly those with severe circumferential MAC and concomitant mitral stenosis. These findings underscore the need for alternative strategies and prospective studies with long-term follow-up to optimize treatment selection in this challenging population.