Simulations of transcatheter aortic valve implantation: implications for aortic root rupture.

Aortic root rupture is one of the most severe complications of transcatheter aortic valve implantation (TAVI). The mechanism of this adverse event remains mostly unknown. The purpose of this study was to obtain a better understanding of the biomechanical interaction between the tissue and stent for patients with a high risk of aortic rupture. We simulated the stent deployment process of three TAVI patients with high aortic rupture risk using finite element method. The first case was a retrospective analysis of an aortic rupture case, while the other two cases were prospective studies, which ended with one canceled procedure and one successful TAVI. Simulation results were evaluated for the risk of aortic root rupture, as well as coronary artery occlusion, and paravalvular leak. For Case 1, the simulated aortic rupture location was the same as clinical observations. From the simulation results, it can be seen that the large calcified spot on the interior of the left coronary sinus between coronary ostium and the aortic annulus was pushed by the stent, causing the aortic rupture. For Case 2 and Case 3, predicated results from the simulations were presented to the clinicians at multidisciplinary pre-procedure meetings; and they were in agreement with clinician's observations and decisions. Our results indicated that the engineering analysis could provide additional information to help clinicians evaluate complicated, high-risk aortic rupture cases. Since a systematic study of a large patient cohort of aortic rupture is currently not available (due to the low occurrence rate) to clearly understand underlying rupture mechanisms, case-by-case engineering analysis is recommended for evaluating patient-specific aortic rupture risk.