Introduction: Transcatheter mitral valve replacement (TMVR) using aortic transcatheter heart valves (THV) is developing as an alternative to surgery for patients with severe mitral valve disease due to degenerated mitral bioprostheses or failed surgical rings who are poor surgical candidates. Outcomes of off-label procedures in the United States are being collected in the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy (STS/ACC TVT) Registry. A comprehensive analysis of mitral Valve-in-Valve (VIV) versus Valve-in-Ring (VIR) outcomes has not previously been performed. Objectives: To evaluate in-hospital and 30-day clinical outcomes of mitral VIV and VIR procedures in the United States.
Methods: Retrospective analysis of data from the STS/ACC TVT Registry on patients who underwent mitral VIV or VIR procedures.
Results: 587 patients underwent TMVR VIV (n=494) or VIR (n=93) procedures between January 2013 and December 2016 at 144 hospitals. Median age was 76 (VIV) and 73 (VIR) years, (p=0.024), 60.9% (VIV) and 44.1% (VIR) were female (p=0.003), median left ventricular ejection fraction was 55% in VIV and 50% in VIR (p <0.001), and median STS score was 10.5% (VIV) and 9.2% (VIR), p=0.131. Transseptal access was utilized in 35% VIV and 46.2% VIR procedures, p=0.081. Procedural success was achieved in 74.4% of VIV and 57.8%VIR (p=0.239). Left ventricular outflow tract (LVOT) obstruction was more common in VIR (5.4%) vs VIV (0.06%), p=0.003. Post-procedure median mean mitral valve gradient was 4mmHg in both groups. 95.7% of VIV and 86% of VIR patients had post-procedure mitral regurgitation ≤1(+), p<0.001. In-hospital mortality was 6.9% for VIV and 9.7% for VIR (p=0.343). 30-day mortality was 9% for VIV and 12% for VIR (p=0.387). At 30-day follow up, 85.6% of VIV and 77.7% of VIR patients were in New York Heart Association class I or II (p=0.398).
Conclusions: TMVR VIV and VIR using aortic transcatheter heart valves in high surgical risk patients are associated with similar in-hospital and 30-day mortality and symptom benefit. LVOT obstruction post-TMVR and residual mitral regurgitation ≥2 (+) were more frequent in VIR procedures. The long-term effect of these procedures is not known and requires further evaluation.