The use of balloon-expandable aortic transcatheter heart valves might improve symptoms, quality of life and stable prosthesis function in patients with severe mitral annular calcification (MAC), failed annuloplasty ring and bioprosthetic mitral valve (MV) dysfunction at 2-year follow-up, a new study suggests.
The Mitral Implantation of Transcatheter Valves (MITRAL) study also found that patients who underwent the mitral valve-in-ring (MViR) implantation experienced higher mortality rates than patients who underwent mitral valve-in-valve (MViV) and valve-in-mitral annular calcification (ViMAC). Thus, survival rates might be greater in patients who receive MViV or ViMAC over MViR.
These data were reported by Mackram F. Eleid, MD, of the Mayo Clinic, and colleagues in a review published Monday online and in the Dec. 6 issue of the Journal of the American College of Cardiology.
Patients who have severe MV disease are at high risk for needing conventional mitral surgery. Less invasive alternatives, such as balloon-expandable aortic transcatheter valves, have been well-studied up to 1-year post-procedure. The MITRAL study investigators chose to evaluate clinical outcomes in patients at the 1-year and 2-year post-procedure timepoints.
This study included patients across 13 U.S. institutions. Patients were required to need treatment for one of three conditions: severe MAC, prior failed mitral annuloplasty ring repair or prior failed bioprosthetic MV replacement who were classified as high-risk for surgery.
Over 3 years, 91 patients were enrolled into three groups: ViMAC (n = 31), MViR (n = 30) and MViV (n = 30). In the ViMAC group, the average age was 75 ± 8 years, 71% were female, 39% had diabetes and the average Society of Thoracic Surgeons (STS) score was 8.6% ± 8.2%. In the MViR group, the average age was 72 ± 9 years, 37% were female, 30% had diabetes and the average STS score was 8.7% ± 4.7%. In the MViV group, the average age was 76 ± 10 years, 63% were female, 20% had diabetes and the average STS score was 10.2% ± 6.5%.
Two-year all-cause mortality was classified into cardiovascular (21.4% ) and noncardiovascular (17.9%) causes. Two-year all-cause mortality rates were 39.3% in the ViMAC, 50% in the MViR and 6.7% in the MViV group. At 2 years, in the ViMAC group, 66.7% of patients were New York Heart Association (NYHA) functional class I-II, and the mean MV gradient was 5.6 ± 2.0 mm Hg. In the MViR group, 65% of patients were NYHA functional class I-II, and the mean MV gradient was 6.5 ± 2.7 mm Hg. Finally, in the MViV group, 85% of patients were NYHA functional class I-II, and the mean MV gradient was 6.9 ± 2.4 mm Hg.
At the 2-year follow-up, all patients presented with mild mitral regurgitation, and survivors in the three groups demonstrated improved scores on the Kansas City Cardiomyopathy Questionnaire (KCCQ) compared to baseline.
The investigators concluded that patients’ quality of life (as measured by the NYHA functional class and KCCQ score) increased at the 2-year follow-up compared to the 1-year follow-up in all three groups, and survival rates were greatest in the MViV group, with the highest mortality rates in the MViR group. The authors did note that this study is not generalizable because of the small, carefully selected pool of participants.
In an editorial commenting on the MITRAL study, R. Jay Widmer, MD, PhD, and Molly Szerlip, MD, of Baylor Scott and White Healthcare, Plano, Texas, discussed how the 2-year results of the MITRAL study show slight improvements from the 1-year results.
The editorialists noted that all three interventions improved quality of life and heart failure symptom reduction at 2 years, but not all interventions had decreased mortality. The ViMAC and MViR groups had higher mortality rates, whereas ViMAC patients had the highest mortality rates at 1 year than the other two groups.
However, the editorialists noted these numbers are comparable to other early heart disease treatments. “… they are in line with 3-year COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation) data in terms of mortality, and clearly superior to medical therapy alone in inoperable patients in whom surgical mitral procedures are prohibitive,” Widmer and Szerlip wrote.
Patient selection is also an important factor in these studies, and though the MITRAL study had a small number of participants, Widmer and Szerlip concluded that, “This [study] sets the stage for larger studies and registries with a variety of patients and therapies that increases the scale of this work to advance the field of mitral valve therapies.”
Eleid MF, Wang DD, Pursnani A, et al. 2-Year Outcomes of Transcatheter Mitral Valve Replacement in Patients with Annular Calcification, Rings, and Bioprostheses. J Am Coll Cardiol. 2022;23:2171–2183.
Widmer JR, Szerlip M. Percutaneous Mitral Valve Replacement. J Am Coll Cardiol. 2022;23:2184–2186.
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