Fig 1.
In silico anatomic models of TAV, BAV Sievers 0, and BAV Sievers 1.
Labelled values are retained throughout all valve models. Hsinotubular junction = 22.1 mm, H1 = 18 mm, H2 = 14 mm, Dannulus = 25 mm, Taorta = 1.5 mm, Tmid leaflet = 0.8 mm, Tleaflet tup = 1.3 mm. Both TAV and BAV Sievers 1 demonstrate commissures that span 120 degrees while BAV Sievers 0 commissures are placed 180 degrees apart.
Fig 2.
TAVR expansion in BAV subtypes, according to the Sievers classification, compared with TAV.
Though Sievers 0 BAV leaflets experience higher Von Mises stress (σVM) than Sievers 1 or TAV leaflets (6.64 MPa vs 4.19 MPa vs Tricuspid 0.55 MPa), stress concentration at the level of the commissures is greater in Sievers 1 BAV (0.316 MPa), than Sievers 0 (0.137 MPa) or TAV (0.056 MPa). Stent displacement, describing the physical deviation of the implanted device as compared to full unrestrained expansion, follows with stress (TAV 0.77 mm, Sievers 0 1.52 mm, Sievers 1 2.49 mm).
Fig 3.
AVR expansion in BAV subtypes, according to the Sievers classification, compared with TAV.
Device axisymmetry is noted by comparison of cross sections taken at the valve annulus (black) and leaflet free edge (red). In TAV and Sievers 0 BAV, device centroid at the annulus (black circle) shows little displacement from the device centroid measured at the leaflet free edge (red circle) (TAV: 0.33 mm, Sievers 0 BAV: 0.23 mm). In Sievers 1 BAV there is marked device eccentricity with 1.09 mm of displacement between the device centroid measured at the annulus and leaflet free edge. Devices in TAV and BAV experience different degrees of opening, with BAV deployment experiencing smaller geometric orifice areas (GOA), illustrated in cross section at the level of the leaflet free edge (TAV 644.68 mm2, BAV Sievers 0 459.18 mm2, BAV Sievers 1 541.55 mm2).
Table 1.
Comparative stresses, strains, and resulting configuration experiences by both patient anatomy and TAVR devices implanted in Sievers 0 BAV, Sievers 1 BAV, and TAV.