Surgical Redo MVR vs. Transcatheter Mitral Valve-in-Valve

Study Questions:

What are the clinical outcomes and echocardiographic findings after transcatheter mitral valve-in-valve replacement (TMVR) compared to redo surgical mitral valve replacement (SMVR)?

Methods:

Patients with a degenerated mitral bioprosthesis who underwent redo SMVR or TMVR at three US institutions between January 2007 and August 2017 were retrospectively identified. Clinical and echocardiographic outcomes of patients who underwent TMVR were compared with those of patients who underwent redo SMVR.

Results:

A total of 62 patients underwent TMVR (14 apical access, 48 transseptal access [including 5 with an apical rail]) and 59 patients underwent SMVR (40 median sternotomy, 19 thoracotomy or mini-thoracotomy, 1 robotic; concomitant tricuspid repair in 8 [17%]) during the study period. Mean age and the Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) scores were significantly higher among patients who underwent TMVR compared to those who underwent SMVR (age 74.9 ± 9.4 years vs. 63.7 ± 14.9 years, p < 0.001; STS-PROM 12.7 ± 8.0% vs. 8.7 ± 10.1%, p < 0.0001). Total procedure time, intensive care unit hours, and post-procedure length of stay all were significantly shorter in the TMVR group. There was no difference in mortality at 1 year between the two groups (TMVR 11.3% vs. SMVR 11.9%; p = 0.92). Mean mitral valve pressure gradient and the grade of mitral regurgitation (MR) at 30 days were not significantly different between the TMVR and SMVR groups (mitral valve pressure gradient 7.1 ± 2.5 mm Hg vs. 6.5 ± 2.5 mm Hg, p = 0.42; MR ≥ moderate 3.8% vs. 5.6%, p = 1.00). At 1 year, the mitral valve pressure gradient was higher in the TMVR group (TMVR 7.2 ± 2.7 vs. SMVR 5.5 ± 1.8; p = 0.01), although there was no difference in the grade of MR (≥ moderate TMVR 4.2% vs. SMVR 4.5%, p = 1.00). However, ≥ moderate tricuspid regurgitation (TR) was more common at 1 year after TMVR than after SMVR (TMVR 68.2% vs. SMVR 37.5%, p = 0.04).

Conclusions:

Despite greater age and higher STS-PROM in TMVR patients, there was no difference in 1-year mortality between the TMVR and SMVR groups. Echocardiographic findings after TMVR were similar to SMVR at 30 days. There was a statistically significant difference in mitral gradient at 1 year, although the authors suggest that this likely is not clinically important. The authors concluded that TMVR may be an alternative to SMVR in patients with previous mitral bioprosthetic valves.

Perspective:

This retrospective, observational study found that, despite greater patient age and higher STS-PROM, patients who underwent TMVR for mitral bioprosthesis degeneration had no difference in 1-year mortality compared to patients who underwent redo SMVR. Careful patient selection presumably contributed to favorable outcomes. Despite no significant difference in the rate of ≥ moderate TR preoperatively and a low rate of concomitant tricuspid valve repair at the time of SMVR, the observed higher rate of significant TR at 1 year deserves consideration. Finally, the durability of TMVR remains unknown, potentially limiting its appropriateness among less elderly patients with mitral bioprosthesis degeneration requiring re-intervention.

Clinical Topics: Cardiac Surgery, Geriatric Cardiology, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Valvular Heart Disease, Cardiac Surgery and VHD, Interventions and Imaging, Interventions and Structural Heart Disease, Echocardiography/Ultrasound, Mitral Regurgitation

Keywords: Bioprosthesis, Cardiac Surgical Procedures, Diagnostic Imaging, Echocardiography, Geriatrics, Heart Valve Diseases, Mitral Valve, Mitral Valve Insufficiency, Sternotomy, Thoracotomy, Treatment Outcome, Tricuspid Valve Insufficiency


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