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Long-term survival after valve replacement with Björk-Shiley CC valves. Björk-Shiley Study Group
M Kallewaard1, A Algra, J Defauw
1Julius Center for Patient Oriented Research, Utrecht University, Medical School, The Netherlands.
Insights
Long-term survival for Bjork-Shiley convexo-concave (BScc) valve recipients is better than previously estimated. Prophylactic replacement guidelines may underestimate true survival, necessitating personalized risk assessment based on age and valve position.
Area of Science:
- Cardiovascular Surgery
- Biomedical Engineering
- Public Health
Background:
- Bjork-Shiley convexo-concave (BScc) valve recipients require accurate life expectancy data for clinical decisions.
- Limited information exists on the long-term outcomes and survival rates of BScc valves.
- Understanding determinants of survival is crucial for patient management and guideline development.
Purpose of the Study:
- To describe long-term survival and its determinants in the Dutch BScc valve recipient cohort.
- To compare mortality figures with the general population and existing prophylactic replacement guidelines.
- To assess the accuracy of current life expectancy estimates for BScc valve recipients.
Main Methods:
- Follow-up data collected for all Dutch BScc valve recipients (n=2,264) up to 1996.
- Kaplan-Meier product-limit method used for survival analysis over 15 years.
- Cox regression analysis identified determinants of survival; Standardized Mortality Ratios (SMRs) compared cohort mortality to the general population.
Main Results:
- 15-year survival rates were 55.0% (aortic), 40.8% (mitral), and 38.6% (double valve recipients).
- SMR was 4.2 in the first year post-surgery, decreasing to 2.0 thereafter and remaining constant.
- SMR varied by time since implantation, patient age at implantation, and valve position.
Conclusions:
- Current life expectancy estimates in prophylactic replacement guidelines for BScc valves often underestimate actual survival.
- Patient age, valve position, and time-specific risks are critical factors influencing post-surgery mortality.
- Personalized risk assessment, considering age-specific excess mortality rates, is recommended for BScc valve recipients.
Abstract:
Information on the life expectancy of Bjork-Shiley convexo-concave (BScc) valve recipients is necessary when considering prophylactic replacement. However, little is known about the late results after valve replacement with BScc valves. We describe long-term survival and its determinants of the Dutch BScc cohort and compare mortality figures with those of the general population and those used in guidelines for prophylactic replacement. Follow-up was obtained on all Dutch BScc valve recipients (n = 2,264) (end of study 1996). Survival over a 15-year period and its determinants were described using the Kaplan-Meier product-limit method and Cox regression, respectively. Standardized mortality ratios (SMRs) were used to compare mortality rates of BScc valve recipients who survived at least 30 days after surgery with the Dutch population rates. Survival at 15 years for aortic, mitral, and double valve recipients was 55.0% (95% confidence interval [CI] 51.9 to 58.1), 40.8% (95% CI 37.1 to 44.4), and 38.6% (95% CI 33.2 to 43.9), respectively. The determinants of survival were patient, history, and procedure related. The SMR for all BScc valve recipients was 4.2 (95% CI 3.4 to 5.2) in the first year of follow-up, after which it decreased to 2.0 (95% CI 1.8 to 2.3) and remained constant until the 14th year. SMRs depended on time since implantation, age at the time of implantation, and position of the valve replaced. Most of life expectancy estimates in prophylactic replacement guidelines of BScc valves underrate the true survival estimates. Age, valve position, and time- specific risks of death after valvular surgery should be accounted for. Different excess mortality rates should be applied for patients from different age groups: the older the patient the lower the excess.