A Finite Element Analysis Study from 3D CT to Predict Transcatheter Heart Valve Thrombosis

Abstract

Background: Transcatheter aortic valve replacement has proved its safety and effectiveness in intermediate- to high-risk and inoperable patients with severe aortic stenosis. However, despite current guideline recommendations, the use of transcatheter aortic valve replacement (TAVR) to treat severe aortic valve stenosis caused by degenerative leaflet thickening and calcification has not been widely adopted in low-risk patients. This reluctance among both cardiac surgeons and cardiologists could be due to concerns regarding clinical and subclinical valve thrombosis. Stent performance alongside increased aortic root and leaflet stresses in surgical bioprostheses has been correlated with complications such as thrombosis, migration and structural valve degeneration. Materials and Methods: Self-expandable catheter-based aortic valve replacement (Medtronic, Minneapolis, MN, USA), which was received by patients who developed transcatheter heart valve thrombosis, was investigated using high-resolution biomodelling from computed tomography scanning. Calcific blocks were extracted from a 250 CT multi-slice image for precise three-dimensional geometry image reconstruction of the root and leaflets. Results: Distortion of the stent was observed with incomplete cranial and caudal expansion of the device. The incomplete deployment of the stent was evident in the presence of uncrushed refractory bulky calcifications. This resulted in incomplete alignment of the device within the aortic root and potential dislodgment. Conclusion: A Finite Element Analysis (FEA) investigation can anticipate the presence of calcified refractory blocks, the deformation of the prosthetic stent and the development of paravalvular orifice, and it may prevent subclinical and clinical TAVR thrombosis. Here we clearly demonstrate that using exact geometry from high-resolution CT scans in association with FEA allows detection of persistent bulky calcifications that may contribute to thrombus formation after TAVR procedure.

CoreValve vs. Sapien 3 Transcatheter Aortic Valve Replacement: A Finite Element Analysis Study

“…It is important to underline that unlike the standard aortic valve replacement, which allows the complete removal of calcifications, in the percutaneous procedure the calcifications are pressed against the aortic wall. The postoperative CT scan fails to show these calcifications [ 11 , 12 ]. Prosthetic stent deformation of both self-expandable and balloon-expandable devices was noted as a consequence of these calcifications, which caused a high degree of mismatch between the native aortic root wall and the stent profile.…”

“…Studies have suggested the role of complex native calcifications of the aortic valve in the occurrence of these complications [ 7 , 8 ]. However, the computed tomography (CT) imaging modalities routinely used in the perioperative work-up for TAVR have proven unable to clearly identify all the anatomical parameters or characteristics predicting the risk of occurrence of device complications [ 11 , 12 ].…”

The 2020 American College of Cardiology/ American Heart Association (ACC/AHA) Guideline for the Management of Patients with Valvular Heart Disease. Should the World Jump In?

“…Non-uniform expansion related to extensive calcifications is responsible for prosthetic device deformation that leads to an eccentricity > 10%, resulting in incomplete expansion of the metallic frame at almost all levels. In a fatigue simulation study, transcatheter valve leaflets were noted to sustain higher stresses, strains, and fatigue damage than did surgical aortic valve leaflets [ 60 ] . Finally, prosthetic valve thrombosis is considered a marker for SVD, and recent echocardiographic data from PARTNER-3 corroborated these concerns, observing leaflet thrombosis as the main cause of SVD at 1 year [ 52 ] .…”

In silico biomechanical design of the metal frame of transcatheter aortic valves: multi-objective shape and cross-sectional size optimization

“…Different TAV frame designs could be investigated as well. Finally, FE simulations could be coupled with computation fluid dynamics simulations, following device implantation, in order to address TAV implantation procedural complications such as PVL (De Jaegere et al 2016;Mao et al 2018;Rocatello et al 2019) and thrombosis (Bianchi et al 2019;Nappi et al 2020).…”