Author + information
- Received June 10, 2015
- Revision received August 11, 2015
- Accepted August 12, 2015
- Published online December 28, 2015.
- Prem A. Midha, MS∗,
- Vrishank Raghav, PhD∗,
- Jose F. Condado, MD, MS†,
- Sivakkumar Arjunon, PhD∗,
- Domingo E. Uceda, BS∗,
- Stamatios Lerakis, MD†,
- Vinod H. Thourani, MD†,
- Vasilis Babaliaros, MD† and
- Ajit P. Yoganathan, PhD∗∗ ()
- ↵∗Reprint requests and correspondence:
Dr. Ajit P. Yoganathan, Georgia Institute of Technology & Emory University, Wallace H. Coulter Department of Biomedical Engineering, Technology Enterprise Park, Suite 200, 387 Technology Circle, Atlanta, Georgia 30313-2412.
Objectives The aim of this study was to investigate the hemodynamic performance of a transcatheter heart valve (THV) deployed at different valve-in-valve positions in an in vitro model using a small surgical bioprosthesis.
Background Patients at high surgical risk with failing 19-mm surgical aortic bioprostheses are not candidates for valve-in-valve transcatheter aortic valve replacement, because of risk for high transvalvular pressure gradients (TVPGs) and patient-prosthesis mismatch.
Methods A 19-mm stented aortic bioprosthesis was mounted into the aortic chamber of a pulse duplicator, and a 23-mm low-profile balloon-expandable THV was deployed (valve-in-valve) in 4 positions: normal (bottom of the THV stent aligned with the bottom of the surgical bioprosthesis sewing ring) and 3, 6, and 8 mm above the normal position. Under controlled hemodynamic status, the effect of these THV positions on valve performance (mean TVPG, geometric orifice area, and effective orifice area), thrombotic potential (sinus shear stress), and migration risk (pullout force and embolization flow rate) were assessed.
Results Compared with normal implantation, a progressive reduction of mean TVPG was observed with each supra-annular THV position (normal: 33.10 mm Hg; 3 mm: 24.69 mm Hg; 6 mm: 19.16 mm Hg; and 8 mm: 12.98 mm Hg; p < 0.001). Simultaneously, we observed increases in geometric orifice area (normal: 0.83 cm2; 8 mm: 1.60 cm2; p < 0.001) and effective orifice area (normal: 0.80 cm2; 8 mm: 1.28 cm2; p < 0.001) and reductions in sinus shear stresses (normal: 153 dyne/cm2; 8 mm: 40 dyne/cm2; p < 0.001), pullout forces (normal: 1.55 N; 8 mm: 0.68 N; p < 0.05), and embolization flow rates (normal: 32.91 l/min; 8 mm: 26.06 l/min; p < 0.01).
Conclusions Supra-annular implantation of a THV in a small surgical bioprosthesis reduces mean TVPG but may increase the risk for leaflet thrombosis and valve migration. A 3- to 6-mm supra-annular deployment could be an optimal position in these cases.
The work at the Cardiovascular Fluid Mechanics Laboratory at the Georgia Institute of Technology was funded through discretionary funds available to Dr. Yoganathan through the Wallace H. Coulter Endowed Chair. Dr. Thourani is a consultant or researcher for Edwards Lifesciences, Medtronic, St. Jude Medical, Sorin Medical, Boston Scientific, Abbott Medical, and DirectFlow Medical. Drs. Babaliaros and Lerakis are consultants or researchers for Edwards Lifesciences and Abbott Medical. Dr. Yoganathan is a consultant or researcher for St. Jude Medical and Boston Scientific. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received June 10, 2015.
- Revision received August 11, 2015.
- Accepted August 12, 2015.
- 2015 American College of Cardiology Foundation