Understanding TAVR device expansion as it relates to morphology of the bicuspid aortic valve: A simulation study

Abstract

The bicuspid aortic valve (BAV) is a common and heterogeneous congenital heart abnormality that is often complicated by aortic stenosis. Although initially developed for tricuspid aortic valves (TAV), transcatheter aortic valve replacement (TAVR) devices are increasingly applied to the treatment of BAV stenosis. It is known that patient-device relationship between TAVR and BAV are not equivalent to those observed in TAV but the nature of these differences are not well understood. We sought to better understand the patient-device relationships between TAVR devices and the two most common morphologies of BAV. We performed finite element simulation of TAVR deployment into three cases of idealized aortic anatomies (TAV, Sievers 0 BAV, Sievers 1 BAV), derived from patient-specific measurements. Valve leaflet von Mises stress at the aortic commissures differed by valve configuration over a ten-fold range (TAV: 0.55 MPa, Sievers 0: 6.64 MPa, and Sievers 1: 4.19 MPa). First principle stress on the aortic wall was greater in Sievers 1 (0.316 MPa) and Sievers 0 BAV (0.137 MPa) compared to TAV (0.056 MPa). TAVR placement in Sievers 1 BAV demonstrated significant device asymmetric alignment, with 1.09 mm of displacement between the center of the device measured at the annulus and at the leaflet free edge. This orifice displacement was marginal in TAV (0.33 mm) and even lower in Sievers 0 BAV (0.23 mm). BAV TAVR, depending on the subtype involved, may encounter disparate combinations of device under expansion and asymmetry compared to TAV deployment. Understanding the impacts of BAV morphology on patient-device relationships can help improve device selection, patient eligibility, and the overall safety of TAVR in BAV.

Patient-specific multi-scale design optimization of transcatheter aortic valve stents

“…The aortic annulus diameter was 23mm, which is in the range of candidates for the Evolut R device of size 26 [25]. In the patient-specific model, the calcified deposits were similar to a general aortic valve calcification pattern (coaptation pattern) [17,26].…”

Leaflet Stresses During Full Device Simulation of Crimping to 6 mm in Transcatheter Aortic Valve Implantation, TAVI

“…This more realistic representation has been used more recently but, again, not through a full crimping range. 17 , 20 …”

A clinical perspective on endovascular stroke treatment biomechanics

“…At the highest level, the. three techniques appear to be equally effective: Two randomized controlled trials have compared stent-retriever thrombectomy to thrombus aspiration and showed similar rates of successful reperfusion (eTICI 2b/3) and clinical outcomes (Lapergue et al, 2017;Turk et al, 2019). Furthermore, the recently presented ASTER II trial showed no significant differences between stentretriever thrombectomy and a primary combined approach, although the rate of near-complete reperfusion was 8% higher in the latter group (Neuronews, 2019).…”

“…Several in silico studies in the field of interventional cardiology have recently been published in this regard (Kusner et al, 2021;Luraghi et al, 2021a), and there are some initial results on stent retriever thrombectomy simulation studies as well (Luraghi et al, 2021b). Once they have found their way into clinical routine, these novel computational approaches may soon assist operators in choosing the optimal thrombectomy approach for a given patient to maximize chances of fast and successful reperfusion.…”