SAVR versus TAVI: What about the Hemodynamic Performance? An In Vivo and In Vitro Analysis

Surgical aortic valve replacement (SAVR) is nowadays discussed whether it remains the gold standard of treatment. In the last decade, there has been a tremendous increase in transcatheter aortic valve implantation (TAVI) due to the growing expertise and excellent results of the catheter-based approach. We, therefore, retrospectively compared the rapid deployment valve (RDV), the Edwards Intuity valve (IEV), with the Edwards Sapien 3 (S3V) with regard to post-procedural hemodynamics.

A total of 246 patients treated with TAVI or SAVR between February 2009 and November 2015 were included. One-hundred twenty-five patients were analyzed in the SAVR group and compared with 121 patients undergoing TAVI. Transvalvular pressure gradients (PGs) and the incidence and extent of aortic regurgitation (AR) were compared post-procedurally by echocardiography for each valve size. In vitro hemodynamics were analyzed by placing both valves into an aortic silicone phantom connected to a pulsatile flow pump and measured using phase-contrast magnetic resonance imaging (4D flow MRI).

Post-procedurally, mean transvalvular PGs for the 23 mm valves were 9 (7;11.5) versus 13 (9;18) (p < 0.001), whereas maximum PGs were 16.5 (14;22) versus 25.5 mm Hg (17.5;34) (p < 0.001) in IEV and S3V patients, respectively. The 21 mm IEV showed significantly lower transvalvular PGs compared with the 23 mm S3V: mean PGs: 11 (8;13) versus 13 (9;18) (p < 0.05); maximum PG: 19.5 (13;24) versus 25.5 (18;34) mm Hg (p < 0.05). Analysis revealed significantly lower post-procedural transvalvular PGs for larger valves sizes. With respect to AR, the incidence of AR was significantly lower in IEV group (p < 0.05). In vitro velocities and turbulent kinetic energy values showed similar results between both valves.

Implanted RDVs presented a lower incidence of paravalvular regurgitation and were associated with significantly lower post-procedural transvalvular PGs, especially for small valve sizes. Our data might support the application of rapid deployment aortic valves in patients with small aortic annulus in the TAVI era.