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Mitral Regurgitation After Percutaneous Mitral Valvuloplasty
Quick Takes
- Following percutaneous mitral valvuloplasty for rheumatic mitral stenosis, patients without significant mitral regurgitation had a 1-year event-free survival rate of 95%.
- The mechanism of mitral regurgitation associated with the least favorable clinical outcomes was damage to the central scallops and/or subvalvular apparatus. More than half of these patients underwent mitral valve replacement during the index admission, and 1-year event-free survival rate in this group was 7%.
Study Questions:
What is the incidence, and what are the mechanisms and clinical outcomes of mitral regurgitation (MR) after percutaneous mitral valvuloplasty (PMV) for rheumatic mitral stenosis (MS)?
Methods:
Consecutive patients who were referred to a tertiary center in Brazil for management of rheumatic MS from 2011 to 2019 were prospectively enrolled in the study. Each patient underwent a comprehensive transthoracic echocardiogram (TTE) and a transesophageal echocardiogram (TEE) with three-dimensional (3D) imaging prior to PMV, and if MR developed post-procedurally, a follow-up 3D TEE was also performed. Postprocedural MR was considered significant if moderate or severe based on effective orifice area. The long-term clinical endpoint was a composite of cardiovascular death or mitral valve replacement (MVR).
Results:
The study population included 344 patients (mean age 45.1 years, 85% women). All patients had severe MS. Median Wilkins score was 7, and 81% of patients were considered low risk for PMV based on the echo score revisited. Significant MR after PMV developed in 64 patients (18.6%). The most common mechanism of MR was commissural (22 patients, 34.4%), followed by posterior leaflet tear with commissural MR (16 patients, 25%) and by severe damage to the central scallop and/or subvalvular apparatus (15 patients, 23.4%). The least common mechanism was central MR associated with excessive valve opening (11 patients, 17.2%).
During a mean follow-up of 3 years, 60 patients reached the composite clinical endpoint (51 MVRs, nine deaths). In patients without significant MR, event-free survival rates were 95% at 1 year and 86% at 9 years. Patients with significant MR due to central scallop/subvalvular damage were particularly likely to undergo MVR (14/15 patients, with nine requiring surgery during the initial hospital stay and five undergoing emergent surgery for tearing of the A2 scallop with hemodynamic instability); their event-free survival rate at 1 year was lowest at 7%. Patients with only commissural MR had event-free survival rates of 89% at 1 year and 81% at 3 years. In a multivariable model, independent predictors of long-term outcomes were MR mechanism (noncommissural MR associated with worse outcomes than commissural MR), post-procedural mitral valve area and mean gradient, change in B-type natriuretic peptide level, and Doppler-derived net atrioventricular compliance. The Wilkins score was not associated with MR after PMV, and although the echo score revisited was associated with MR, the discrimination was poor (C-statistic, 0.60).
Conclusions:
Moderate or severe MR following PMV for rheumatic MS occurs in approximately 1/5 of patients. Patients with commissural MR have the most favorable outcomes, while those with MR due to damage of the central scallop/subvalvular apparatus have poor event-free survival.
Perspective:
This relatively large series of patients with rheumatic MS is a valuable addition to the literature, clarifying mechanisms of post-PMV MR and their prognostic implications. Further research will be needed to clarify echocardiographic characteristics that increase risk of postprocedural MR, particularly MR associated with central scallop damage, as those patients seem to be at highest risk for acute postprocedural complications. The findings of this study suggest that cardiac surgery backup for PMV is important to ensure patient safety.
Clinical Topics: Cardiac Surgery, Cardiovascular Care Team, 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: Cardiac Surgical Procedures, Diagnostic Imaging, Disease-Free Survival, Echocardiography, Echocardiography, Transesophageal, Heart Valve Diseases, Hemodynamics, Imaging, Three-Dimensional, Mitral Valve Insufficiency, Mitral Valve Stenosis, Natriuretic Peptide, Brain, Rheumatic Heart Disease, Balloon Valvuloplasty
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