Mid-term Survival, Clinical and Hemodynamic Outcomes of a New Generation Mechanical Mitral Valve Prosthesis: 5-year Results from a Randomized Trial
M. Chu1, M. Ruel2, M. Gerdisch3, R. Damiano4, R. Smith5, W. Brent. Keeling6, M. Wait7, R. Hagberg8, G. Sethi9, A. L. Pruitt10, K. Accola11, F. Dagenais12, A. Markowitz13, J. Ye14, M. Sekela15, D. Swistel16, L. Harville17, E. Lehr18, J. DeRose19, J. Puskas20 1Western University, London Health Sciences Centre, London, Ontario 2University of Ottawa Heart Institute, Ottawa, Ontario 3Franciscan Health Indianapolis, Indianapolis, Indiana 4Washington University School of Medicine, St. Louis, Missouri 5Cardiac Surgical Specialists, Plano, Texas 6Emory University, Atlanta, Georgia 7University of Texas - Southwestern Medical Center, Dallas, Texas 8Hartford Healthcare Medical Group Cardiac Surgery, Hartford, Connecticut 9Tucson Medical Center, Tucson, Arizona 10Michigan Heart & Vascular Institute - CT Surgeons of Ann Arbor, Ypsilanti, Michigan 11Adventhealth CardioThoracic Surgery, Orlando, Florida 12Laval University, Quebec City, Quebec 13University Hospitals of ClevelandX, Cleveland, Ohio 14St. Paul's Hospital, Vancouver, British Columbia 15University of Kentucky, Lexington, Kentucky 16NYU Langone Medical Center, New York, New York 17University of Oklahoma, Oklahoma City, Oklahoma 18Swedish Heart and Vascular Institute, Seattle, Washington 19Montefiore-Einstein, Norwood, New Jersey 20Mount Sinai Morningside Hospital, New York, New York
Chair/Chief, Professor of Surgery Western University, London Health Sciences Centre London, Ontario, Canada
Disclosure(s):
Michael Chu, MD, FRCSC: No relevant disclosure to display
Purpose: Prior clinical studies showed optimal flow with a new generation mechanical mitral valve with a single, nominal orifice area mounted on 4 different cuffs compensating for varying annular sizes (1,2). This report presents the 5-year clinical and hemodynamic performance using data from an FDA-monitored, randomized, controlled trial (3). Methods: The trial included 401 patients, >3 months after implantation of a mechanical mitral prosthesis at 44 centers in North America, comparing standard (2.5-3.5) to low INR (2.0-2.5). Patients were clinically followed annually through 8 years, with core-laboratory adjudicated transthoracic echocardiograms at 1, 3, and 5 years. Analyses by body surface area (BSA) and across different labeled valve sizes assessed mean pressure gradients (MG) over time. The interaction between BSA and labeled valve size was tested using a factorial ANOVA. Change in MG from 1 year to 3 or 5 years were evaluated using a paired t-test or Wilcoxon signed rank test. Possible interactions between BSA and labeled valve size on MG changes were explored using MANOVA for repeated measurements. Results: At operation, patients had a mean age of 55±11 years, 61% were women and 73% were symptomatic. The most common etiology was rheumatic disease. Fifty-one percent (n=203) underwent implantation with a standard cuff (25mm, 27/29mm, 31/33mm) and 49% (n=198) with a conform-X cuff (25/33mm). At a mean follow-up of 4.1 years, there were thirty deaths (4 valve-related), with a linearized rate (LOR) of 1.8 %/pt-yr. Actuarial survival was 92% at 5 years overall (Figure 1) with 91% and 94% for standard and conform-X cuffs (p=0.54), respectively. Re-operation was required in 11 patients, with a LOR of 0.66 %/pt-yr. Over time, analyses by labeled valve size (Figure 2), individually or all sizes combined, and BSA showed no statistical differences, suggesting stable hemodynamic valve performance. There was no relationship between labeled valve size and BSA on changes in MG (interaction p-value: 0.36). At 1 year, there was a slight increase in MG with increasing BSA (p-value 0.0023), and in patients with 25mm and 27/29mm labeled valve sizes. The trend was driven by MG results in higher BSAs. MG across the 4 labeled valve sizes was not statistically different within time-period. At 5-years, 87% were in NYHA class I or II. Conclusion: In the PROACT mitral trial, patients experienced excellent survival and good hemodynamic performance after implantation of a new generation mitral valve, with low valve-related morbidity. Functional status and hemodynamics were stable over 5 years for the single internal orifice area across 4 cuff sizes accommodating different anatomies, regardless of BSA.
Identify the source of the funding for this research project: Funded by CryoLife/Artivion; PROACT ClinicalTrials.gov number, NCT00291525
