Structural Changesofthe Right Fibrous Trigone as a Risk Factor for Conduction Disturbance After Transcatheter Aortic Valve Implantation

Background: The right fibrous trigone, which the His bundle penetrates, is part of the subaortic area adjacent to the membranous septum. Structural alterations of the right fibrous trigone may cause conduction disturbance as a result of compression in this area after transcatheter aortic valve implantation. This study analyzed the hypothesis of whether imaging parameters of the RFT could predict the risk of conduction disturbance after transcatheter aortic valve implantation.

Methods: We retrospectively examined 209 patients who underwent transfemoral transcatheter aortic valve implantationat a tertiary cardiac center. The different valve models were divided into 2 groups: self-expanding valve and balloon-expandable valve. Using pre-procedure computed tomography, we evaluated for the alterations of the right fibrous trigone.

Results: New conduction disturbance was seen in 75 of 209 (35.8%) patients. Receiver operating characteristics plots displayed a right fibrous trigone density of −6 Hounsfieldunit for SEV and −16 Hounsfield unit for balloon-expandable valve as the optimal cut- off points for prediction conduction disturbance. In multiple regression analyses, the high density of RFT emerged as an independent predictor of conduction disturbance in both the self-expanding valve (odds ratio: 1.01, 95% CI: 1.01 to 1.02, P = 0.035) and bal- loon-expandable valve (odds ratio: 1.01, 95% CI: 1.01 to 1.03, P = 0.017) groups. A shorter membranous septum length and a greater implantation depth were also found to be significantly associated with a higher incidence of conduction disturbance in both trans- catheter aortic valve implantation groups.

Conclusion: High density of right fibrous trigone is independently associated with con- duction disturbance after transcatheter aortic valve implantation, and its pre-proce- dure computed tomography evaluation can help predict the new-onset of conduction disturbance.