Numerical investigation of the effects of pre-dilatation on paravalvular leakage during transcatheter aortic valve implantation

Due to promising results, the patient cohort for transcather aortic valve replacement (TAVR) has been extended in recent years to include patients with a bicuspid aortic valve (BAV). There are different types of BAV. One variant is the tricommisural bicuspid aortic valve (TBAV). BAV have an increased risk of post-TAVR complications such as paravalvular leakage. In the case of paravalvular leakage, blood flows past the prosthesis back into the ventricle during diastole. Clinically, patients with BAV are often pre-dilated. For this reason, we want to investigate how pre-dilatation of BAV can affect the leakage rate. A simplified model is used for pre-dilatation, where the calcification nodule is cut along the free edge of the leaflets before the deployment. In order to evaluate the effects of this method, a deployment simulation was carried out for both geometries using an explicit calculation. A flow simulation was then performed to determine the paravalvular leakage. The pre-dilatation allows the leaflets to move independently of each other. Without pre-dilatation, the TAVR cannot fully expanded. The leakage rate is higher for the BAV than for the pre-dilated geometry (53.1mLs-1 vs. 19.4mLs-1). In this model, we have shown the effect of pre-dilatation on implantation results.