Anatomical Evaluation Of Balloon-expandable Transcatheter Aortic Valve Replacement - Computed Tomography Insights For Hypo-attenuating Leaflet Thickening
Miho Fukui, Vinayak N. Bapat, Santiago Garcia, Hirotomo Sato, Maurice Enriquez-Sarano, John R. Lesser, Joao L. Cavalcante, Paul Sorajja.
Minneapolis Heart Institute Foundation, Minneapolis, MN, USA.
OBJECTIVE: While transcatheter aortic valve replacement (TAVR) therapy has become a standard therapy, there have been concerns regarding the occurrence of hypo-attenuating leaflet thickening (HALT), which may affect prosthesis durability. Mechanistic insight into causative factors for HALT remains limited. This study sought to examine the occurrence of non-uniform expansion of TAVR prostheses, and correlate its extent to the frequency of HALT.
METHODS: We prospectively examined 352 patients with cardiac CT screening for HALT at 30-day following balloon-expandable TAVR with 23, 26, or 29 mm prostheses. Deformation of the TAVR prostheses, prosthesis sinus volumes, and commissural alignment were analyzed on the post-procedural CT (Figure A and B). For descriptive purposes, an index of TAVR deformation was calculated, with values >1.00 representing relative underexpansion of the mid-segment of the prosthesis.
RESULTS: Overall, underexpansion of the mid-segment of the prosthesis was common, with an index >1.05 present in 92%. Among all patients, HALT was present in 21%, and directly associated with greater THV deformation (index, 1.12[1.10-1.13] vs. 1.08[1.06-1.10]; HALT vs. no HALT; p<0.001). Smaller TAVR sinus volume was related to worse prosthesis deformation, and also was associated with HALT across the range of prosthetic sizes (all p<0.01) (Figure C). In multivariate analyses that include clinical variables previously associated with HALT (e.g., anticoagulant therapy), only the deformation index and TAVR sinus volume remained associated with HALT across all valve sizes.
CONCLUSIONS: Deformation of THV prosthesis with balloon-expandable TAVR therapy is common, and its extent is independently associated with HALT across a range of commonly used prosthesis sizes, with a stronger relation than that observed for other clinical variables. THV deformation might explain HALT occurrence, which will have implications for clinical management and valve design strategies that might mitigate its risk and potential consequences.
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