Bioprosthetic Valve Fracture Performed Before Versus After Viv Tavr: Impact Of High-pressure Balloon Inflation On Leaflet Calcification
Keith B. Allen1, Adnan K. Chhatriwalls2, Abdul Yousef3, Tara Tod3, Adam Greenbaum4, Brian Whisenant5, Michael Mack6, Janarthanan Sathananthan7, John Webb7
1St. Luke's Mid America Heart Institute, Kansas City, MO, USA, 2St. Luke's Mid America Heart Institute, KANSAS CITY, MO, USA, 3Edwards Life Science, Irvine, CA, USA, 4Emory University, Atlanta, GA, USA, 5Intermountain Healthcare, Murry, UT, USA, 6Baylor Health Care System, Plano, TX, USA, 7St. Paul's Hospital, University of British Columbia, Vancouver, BC, Canada
BACKGROUND: Bioprosthetic valve fracture (BVF) can optimize transcatheter heart valve (THV) expansion and reduce transvalvular gradients during valve-in-valve transcatheter aortic valve replacement (VIV TAVR). However, the optimal timing of BVF remains debatable with unknown impact of high-pressure balloon inflation on the structural integrity and durability of THV leaflets.
METHODS: BVF was performed before and after VIV TAVR and THV leaflets were compared using an accelerated leaflet calcification animal model. For the test group (n=8), 23 mm SAPIEN 3 THVs were implanted into 21 mm Magna surgical valves followed by BVF using a 23 mm TRUE balloon. For the control group (n=7), the same size/type of THV and surgical valves were utilized (n=7), however, BVF was performed before VIV TAVR. THV leaflets were removed, cut into multiple 6mm samples and implanted intramuscularly into New Zealand rabbits. Rabbits were survived for a mean of 60±5 days followed by calcium content testing.
RESULTS: The fracture threshold of the surgical valves was similar between groups and ranged from 18-22.5 atmospheres. Regardless of whether BVF was performed before or after VIV TAVR, gross visual inspection of the excised leaflets demonstrated no acute leaflet injury in either group. A total of 124 tissue disc samples were obtained from THVs in the test group (n=62) and control group (n=62) and implanted intramuscularly in 31 rabbits. Leaflet calcium content is summarized in Table 1. No difference in leaflet calcification was observed between test and control samples (113.5 ± 71.2 vs 114.6 ± 70.2 mcg Ca/mg tissue dry, p = 0.8; 95% confidence intervals -18.7, 19.5).
CONCLUSION: In vitro testing demonstrates that the high pressure exerted from a non-compliant TRUE balloon on SAPIEN 3 THV leaflets when BVF is performed after VIV TAVR does not result in accelerated leaflet calcification in a rabbit model.
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