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Low-Risk TAVR Durability vs. Predicted Life Expectancy
Quick Takes
- Discrete event simulation analysis was used in this study to try to model the effects of TAVR device durability on predicted life expectancy after TAVR in a hypothetical low-risk population with characteristics similar to the PARTNER 3 trial.
- Based on the simulation model, the durability of TAVR valves must be 70% shorter than that of surgical valves to result in reduced life expectancy in older low-risk patients.
- The threshold for TAVR device durability was substantially higher in younger low-risk patients.
Study Questions:
Using discrete event simulation (DES), what effect does bioprosthesis durability have on predicted life expectancy after transcatheter aortic valve replacement (TAVR) in patients at low risk?
Methods:
DES (a decision analytic technique that uses patient-level simulation to model competing events) was used to model hypothetical scenarios of TAVR versus surgical aortic valve replacement (SAVR) durability, where TAVR failure times were varied to determine the impact of TAVR durability on life-expectancy in a cohort of low-risk patients similar to those in recent trials. A DES model was constructed using a hypothetical patient population with characteristics similar to the PARTNER 3 trial, a recent randomized clinical trial that compared balloon-expandable TAVR to SAVR in a low-risk group (Society of Thoracic Surgeons–Predicted Risk of Mortality <4%). DES modeling was used to estimate the tradeoff between a less invasive procedure with unknown valve durability (TAVR) and that of a more invasive procedure with known durability (SAVR). Standardized differences were calculated, and a difference >0.10 was considered clinically significant. In the base case analysis, patients with structural valve deterioration requiring reoperation were assumed to undergo a valve-in-valve TAVR procedure. A sensitivity analysis was conducted to determine the impact of TAVR device durability on life expectancy in younger age groups (40, 50, and 60 years).
Results:
The hypothetical cohort consisted of low surgical risk aortic stenosis patients with mean age 73.4 ± 5.9 years. In the base case scenario, standardized difference in life expectancy was <0.10 between TAVR and SAVR until TAVR device failure time was 70% shorter than the SAVR device. At a TAVR device failure time <30% compared to surgical valves, SAVR was the preferred option. In younger patients, life expectancy was reduced when TAVR durability was 30%, 40%, and 50% shorter than surgical valves in 40-, 50-, and 60-year-old patients, respectively.
Conclusions:
Based on simulation models, the durability of TAVR valves must be 70% shorter than that of surgical valves to result in reduced life expectancy in patients with demographics similar to recent trials. However, in younger patients, the threshold for TAVR device durability was substantially higher. The authors concluded that the findings suggest that durability concerns should not influence the initial treatment decision regarding TAVR versus SAVR in older low-risk patients; but that, in younger low-risk patients, valve durability must be weighed against other patient factors such as life expectancy.
Perspective:
Recent clinical trials suggest that TAVR is noninferior and may be superior to SAVR in terms of mortality, stroke, and rehospitalization; however, the long-term durability of TAVR devices, and the impact of durability on outcomes, remains uncertain. This interesting study used DES modeling to try to anticipate how much compromise in bioprosthesis durability associated with TAVR would be necessary to (hypothetically) outweigh lower periprocedural complications compared to SAVR. Although the study is limited by its model that assumed normal life expectancy after AVR for aortic stenosis, it yielded reassuring findings at least among older low-risk patients. It is a conundrum of heart valve clinical research that true long-term device durability data are not known until devices have evolved, so that the long-term durability of a device currently being implanted in essence is never known. Although making clinical decisions based on modeling certainly has caveats, this study at least adds support to the use of TAVR rather than SAVR among older low-risk patients.
Clinical Topics: Cardiac Surgery, Geriatric Cardiology, Invasive Cardiovascular Angiography and Intervention, Valvular Heart Disease, Aortic Surgery, Cardiac Surgery and VHD, Interventions and Structural Heart Disease
Keywords: Aortic Valve Stenosis, Bioprosthesis, Cardiac Surgical Procedures, Geriatrics, Heart Valve Diseases, Heart Valve Prosthesis, Life Expectancy, Reoperation, Risk, Stroke, Transcatheter Aortic Valve Replacement
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