Key result
Testing transcatheter aortic valves in patient-specific replicas demonstrated a decline in hemodynamic performance compared to idealized ISO testing, correlated with stent radial expansion.
Why the study?
Current ISO standard testing of transcatheter aortic valves in idealized geometries excludes effects that may hamper in situ clinical performance, which might be addressed using patient-specific replicas.
In vitro testing of TAVs in patient-specific replicas reveals performance declines not captured by standard idealized ISO testing, suggesting a need for complementary testing methods.
Standard ISO testing may underestimate TAV hemodynamic performance in patient anatomies; leaves open whether regulatory benchmarks require patient-specific validation.
Following in vitro tests established for surgical prosthetic heart valves, transcatheter aortic valves (TAV) are similarly tested in idealized geometries-excluding effects that may hamper TAVR performance in situ. Testing in vitro in pulse duplicator systems that incorporated patient-specific replicas would enhance the testing veracity by bringing it closer to the clinical scenario. To that end we compare TAV hemodynamic performance tested in idealized geometries according to the ISO standard (baseline performance) to that obtained by testing the TAVs following deployment in patient-specific replicas. Balloon-expandable (n = 2) and self-expandable (n = 3) TAVs were tested in an idealized geometry in mock-circulation system (following ISO 5840-3 guidelines) and compared to the measurements in a dedicated mock-circulation system adapted for the five patient-specific replicas. Patient-specific deployments resulted in a decline in performance as compared to the baseline idealized testing, as well as a variation in performance that depended on the design features of each device that was further correlated with the radial expansion and eccentricity of the deployed TAV stent (obtained with CT-scans of the deployed valves). By excluding the deployment effects in irregular geometries, the current idealized ISO testing is limited to characterize the baseline device performance. Utilizing patient-specific anatomic contours provides performance indicators under more stringent conditions likely encountered in vivo. It has the potential to enhance testing and development complementary to the ISO standard, for improved TAV safety and effectiveness.
No takes yet. Share an insight, caveat, or question.
Kovarovic et al. (2020) studied Transcatheter aortic valve replacement (n=5). Patient-specific replicas vs. Idealized geometries (ISO standard) was evaluated on Hemodynamic performance. Testing transcatheter aortic valves in patient-specific replicas demonstrated a decline in hemodynamic performance compared to idealized ISO testing, correlated with stent radial expansion.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: