Valve Type, Size, and Deployment Location Affect Hemodynamics in an In Vitro Valve-in-Valve Model.

OBJECTIVES: The purpose of this study was to optimize hemodynamic performance of valve-in-valve (VIV) according to transcatheter heart valve (THV) type (balloon vs. self-expandable), size, and deployment positions in an in vitro model.

BACKGROUND: VIV transcatheter aortic valve replacement is increasingly used for the treatment of patients with a failing surgical bioprosthesis. However, there is a paucity in understanding the THV hemodynamic performance in this setting.

METHODS: VIV transcatheter aortic valve replacement was simulated in a physiologic left heart simulator by deploying a 23-mm SAPIEN, 23-mm CoreValve, and 26-mm CoreValve within a 23-mm Edwards PERIMOUNT surgical bioprosthesis. Each THV was deployed into 5 different positions: normal (inflow of THV was juxtaposed with inflow of surgical bioprosthesis), -3 and -6 mm subannular, and +3 and +6 mm supra-annular. At a heart rate of 70 bpm and cardiac output of 5.0 l/min, mean transvalvular pressure gradients (TVPG), regurgitant fraction (RF), effective orifice area, pinwheeling index, and pullout forces were evaluated and compared between THVs.

RESULTS: Although all THV deployments resulted in hemodynamics that would have been consistent with Valve Academic Research Consortium-2 procedure success, we found significant differences between THV type, size, and deployment position. For a SAPIEN valve, hemodynamic performance improved with a supra-annular deployment, with the best performance observed at +6 mm. Compared with a normal position, +6 mm resulted in lower TVPG (9.31 ± 0.22 mm Hg vs. 11.66 ± 0.22 mm Hg; p < 0.01), RF (0.95 ± 0.60% vs. 1.27 ± 0.66%; p < 0.01), and PI (1.23 ± 0.22% vs. 3.46 ± 0.18%; p < 0.01), and higher effective orifice area (1.51 ± 0.08 cm(2) vs. 1.35 ± 0.02 cm(2); p < 0.01) at the cost of lower pullout forces (5.54 ± 0.20 N vs. 7.09 ± 0.49 N; p < 0.01). For both CoreValve sizes, optimal deployment was observed at the normal position. The 26-mm CoreValve, when compared with the 23-mm CoreValve and 23-mm SAPIEN, had a lower TVPG (7.76 ± 0.14 mm Hg vs. 10.27 ± 0.18 mm Hg vs. 9.31 ± 0.22 mm Hg; p < 0.01) and higher effective orifice area (1.66 ± 0.05 cm(2) vs. 1.44 ± 0.05 cm(2) vs. 1.51 ± 0.08 cm(2); p < 0.01), RF (4.79 ± 0.67% vs. 1.98 ± 0.36% vs. 0.95 ± 1.68%; p < 0.01), PI (29.13 ± 0.22% vs. 6.57 ± 0.14% vs. 1.23 ± 0.22%; p < 0.01), and pullout forces (10.65 ± 0.66 N vs. 5.35 ± 0.18 N vs. 5.54 ± 0.20 N; p < 0.01).

CONCLUSIONS: The optimal deployment location for VIV in a 23 PERIMOUNT surgical bioprosthesis was at a +6 mm supra-annular position for a 23-mm SAPIEN valve and at the normal position for both the 23-mm and 26-mm CoreValves. The 26-mm CoreValve had lower gradients, but higher RF and PI than the 23-mm CoreValve and the 23-mm SAPIEN. In their optimal positions, all valves resulted in hemodynamics consistent with the definitions of Valve Academic Research Consortium-2 procedural success. Long-term studies are needed to understand the clinical impact of these hemodynamic performance differences in patients who undergo VIV transcatheter aortic valve replacement.