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Clinical Performance of Mechanical Aortic Valve Prostheses
Quick Takes
- In an observational, population-based, nationwide cohort study of adult patients who underwent bileaflet mechanical aortic valve replacement in Sweden from 2003 through 2018, the 10-year mortality for patients with a Bicarbon model (27%, 95% CI, 21%-34%) was significantly higher than that for patients with a Carbomedics model (17%, 95% CI, 15%-18%), Regent model (17%, 95% CI, 13%-20%), or Standard model (17%, 95% CI, 14%-19%).
- There were no statistically significant differences in secondary endpoints of the incidence of HF hospitalization or bleeding.
- Additional research on the comparative long-term performance of the Bicarbon valve would be of interest.
Study Questions:
Is there a difference in clinical performance between different bileaflet mechanical aortic valve prostheses?
Methods:
Data from the Swedish Cardiac Surgery Registry (part of the SWEDEHEART Register) were used to identify patients ≥18 years old who underwent mechanical aortic valve replacement (AVR) using a bileaflet mechanical valve (including On-X, Carbomedics, Bicarbon, Standard, Regent, Open Pivot, Masters, and Advantage valve models) in Sweden from 2003 through 2018; including patients with concomitant coronary artery bypass grafting or ascending aorta surgery but excluding patients with prior surgical or transcatheter AVR, patients undergoing surgery on another valve, and patients undergoing deep hypothermic or circulatory arrest. The National Patient Register was used to collect baseline characteristics and outcomes data. The primary outcome was all-cause mortality. Secondary outcomes were reintervention; heart failure (HF) hospitalization; bleeding; and stroke, transient ischemic attack (TIA), or embolic event. Regression standardization was used to account for baseline differences.
Results:
A total of 5,224 patients (aged 56.8 ± 11.7 years; 3,908 [74.8%] men) were included. Total follow-up time was 43,982 person-years (mean 8.4 ± 4.6 years, maximum 17.2 years). After regression standardization, there was a significant difference in 10-year mortality between the Carbomedics model group (17%, 95% confidence interval [CI], 15%-18%), Regent model group (17%, 95% CI, 13%-20%), and Standard model group (17%, 95% CI, 14%-19%) compared with the Bicarbon model group (27%, 95% CI, 21%-34%). The 10-year incidence of reintervention was statistically lower in the Bicarbon group (0.8%, 95% CI, 0.1-5.5%) and Open Pivot group (albeit with small numbers of events) than in the Standard group, Regent, On-X, and Masters (5.4%, 95% CI, 3.1-9.1%) groups. The 10-year incidence of stroke, TIA, or embolic event was statistically lower in the Regent group (6.2%, 95% CI, 4.2-9.1%) than in the On-X group (10.5%, 95% CI, 7.7-14.3%) and Carbomedics group (10.6%, 95% CI, 8.8-12.7%). There were no significant differences between valve model groups in the incidence of HF hospitalization or bleeding.
Conclusions:
In this cohort study of bileaflet mechanical surgical AVR outcomes in Sweden, the rate of all-cause mortality was higher in the Bicarbon group than in the Carbomedics, Regent, and Standard model groups. The authors conclude that these findings warrant further research on the long-term clinical performance of the Bicarbon valve.
Perspective:
Differences in clinical outcomes are known to exist between various bioprosthetic valve models, and between different mechanical prosthesis designs (caged ball, tilting disc, bileaflet). Most previously published studies report prosthesis performance of a single valve model or a comparison between two valve models. Data from this large, population-based, nationwide cohort study suggest that all bileaflet mechanical aortic valve prostheses might not be clinically equivalent. No statistically significant differences were found between groups in secondary endpoints of HF hospitalization or bleeding, and small numbers of events for reintervention might lead to caution in the interpretation of observed differences between groups. However, the finding of substantially higher 10-year mortality associated with the Bicarbon valve as a relative outlier raises concern. As the authors suggest, additional research on the comparative long-term performance of this device would be of interest.
Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Cardiac Surgery and VHD
Keywords: Cardiac Surgical Procedures, Heart Valve Prosthesis
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