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Transcatheter Versus Surgical Pulmonary Valve Replacement: A Side-by-side Structural And Hemodynamic Characterization
Mina Shafiei, Dong Qiu, Ali Azadani.
University of Denver, Denver, CO, USA.

OBJECTIVE: Transcatheter pulmonary valve replacement (TPVR) is a less invasive alternative to surgical pulmonary valve replacement for pediatric patients with pulmonary stenosis. Some of the bioprosthetic valves used in TPVR, such as SAPIEN 3 (S3), are originally designed for the aortic position. Good short-term outcomes have been observed following TPVR with S3. However, the long-term outcomes are not fully determined, and complications such as subclinical leaflet thrombosis have been recognized following TPVR. This study aimed to perform a side-by-side comparison of S3 and a commonly used surgical bioprosthesis (PERIMOUNT Magna Ease) under pulmonary conditions.
METHODS: Hemodynamic characteristics of a 26-mm S3 and a 25-mm Magna Ease were evaluated in a pulse duplicator under pulmonary and aortic conditions (both child and adolescent). Detailed structural analysis of the leaflets was also obtained under the conditions using computational simulations in Abaqus/Explicit.
RESULTS: The effective orifice area of S3 was significantly more than Magna Ease under the normal pulmonary conditions (p=0.004). High-speed video recordings showed that S3 closed completely in the diastole under the pulmonary conditions. However, the Magna Ease did not reach complete closure under the pulmonary conditions. This contrasted with the aortic testing condition, where full valve closure was attained in both bioprostheses. The simulation results showed that the peak of maximum in-plane principal stress in S3 was more than Magna Ease in the diastole in pulmonary and aortic conditions (Figure-1). The results also indicated that S3 opening area was significantly smaller under the pulmonary conditions than the aortic condition. The altered leaflet kinematics can increase blood stasis on the S3 leaflets.
CONCLUSIONS: The study improves our understanding of the biomechanics involved in TPVR. Hemodynamic and structural characteristics of the S3 and Magna Ease differed considerably between the pulmonary and aortic conditions.


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