Outcome of transcatheter aortic valve replacement in bicuspid aortic valve stenosis with new-generation devices

Abstract

Objectives: To compare device success and paravalvular leak rates of 3 new-generation transcatheter aortic valve replacement devices in patients with bicuspid aortic valve stenosis and to test their biomechanical performance in a computer-based simulation model of aortic root with increasing ellipticity.

Methods: This retrospective multicentre study included 56 bicuspid aortic valve patients undergoing transcatheter aortic valve replacement with new-generation devices: Lotus/Lotus Edge (N = 15; 27%), Evolut-R (N = 20; 36%) and ACURATE neo (N = 21; 37%). Three virtual simulation models of aortic root with increasing index of eccentricity (0-0.25-0.5) were implemented. Stress distribution, stent-root contact area and paravalvular orifice area were computed.

Results: Device success was achieved in 43/56 patients (77%) with comparable rates among Lotus (87%), Evolut-R (60%) and ACURATE neo (86%; P = 0.085). Moderate paravalvular leak rate was significantly lower in the Lotus group as compared to Evolut-R group (0% vs 30%; P = 0.027) and comparable to the ACURATE neo group (0% vs 10%; P = 0.33). By index of eccentricity = 0.5, Lotus showed a uniform and symmetric pattern of stress distribution with absent paravalvular orifice area, ACURATE neo showed a mild asymmetry with small paravalvular orifice area (1.1 mm2), whereas a severely asymmetric pattern was evident with Evolut-R, resulting in a large paravalvular orifice area (12.0 mm2).

Conclusions: Transcatheter aortic valve replacement in bicuspid aortic valve patients with new-generation devices showed comparable device success rates. Lotus showed moderate paravalvular leak rate comparable to that of ACURATE neo and significantly lower than Evolut-R. On simulation, Lotus and ACURATE neo showed optimal adaptability to elliptic anatomies as compared to Evolut-R.

Keywords: Bicuspid aortic valve; Computational simulation; New-generation devices; Transcatheter aortic valve replacement.

Figure 1:

Postprocedural outcome and simulation postprocessing. Device success (A); moderate paravalvular leak (B); mean aortic gradient (P-values are Bonferroni corrected) (C); stent–root interaction area (D), average Von Mises stress distribution (E) and paravalvular orifice area (F).

Figure 2:

Simulation analysis. Patterns of stent–root interaction area (first row) and Von Mises stress distribution (second row) by increasing IE among the 3 devices; resultant paravalvular orifice areas (third row) are displayed. IE: index of eccentricity.

Figure 3:

Case example with ACURATE neo size L. Type I bicuspid aortic valve stenosis with very elliptic shape of the orifice (inter-commisural distance: 31.6 mm) and high calcium burden (A, B); final fluoroscopy shows the elliptic accommodation of ACURATE neo in right caudal and left cranial respectively with no residual paravalvular leak (C, D); despite valve compression, the final hemodynamics show a mean aortic gradient of 13 mmHg and absence of paravalvular leak (E); postprocedural computed tomography angiography shows the excellent stent conformability of ACURATE neo to the elliptic shape of bicuspid aortic valve (max diameter: 31.1 mm; min diameter: 8.1 mm; index of eccentricity = 0.74), with the maximal stent diameter matching the inter-commissural distance (F).

Figure 4:

Case example with Evolut-R 34 mm. Type I bicuspid aortic valve stenosis (inter-commisural distance: 30.2 mm) (A); final angiography shows deep implantation of the prosthesis at the level of left-coronary cusp, with no significant paravalvular leak (B); on transthoracic echocardiography, the prosthesis has excellent transvalvular gradients, but a mild paravalvular leak is evident (C, D); on computed tomography angiography, the prosthesis retained a more circular shape (max diameter: 24.9 mm; min diameter: 18.2 mm; index of eccentricity = 0.27) and failed to fully adapt to the elliptic shape of bicuspid aortic valve (maximal stent diameter < inter-commissural distance), thus leaving a gap (arrow, E, F).