Mitral valve-in-valve hemodynamic performance: An in vitro study.

Area of Science:

• Cardiovascular Research
• Biomedical Engineering
• Prosthetic Valve Technology

Background:

• The valve-in-valve (VinV) procedure is an option for high-risk patients with failed mitral surgical bioprostheses.
• Assessing the hemodynamic performance of different VinV configurations is crucial for patient selection and procedural success.

Purpose of the Study:

• To evaluate the hemodynamic function of various valve-in-valve (VinV) configurations in failed mitral surgical bioprostheses.
• To identify factors influencing hemodynamic outcomes in the VinV procedure for mitral valve replacement.

Main Methods:

• An in vitro study utilizing a double activation duplicator to test 11 surgical bioprostheses and 15 VinV configurations.
• Hemodynamic conditions were simulated under 8 different scenarios.
• Internal orifice diameter (IOD) of surgical bioprostheses was measured using a Smartscope.

Main Results:

• The VinV procedure resulted in significantly worse antegrade hemodynamic parameters, including reduced effective orifice area and increased regurgitant fraction, compared to surgical bioprostheses alone.
• Moderate to severe mitral stenosis occurred in 52 of 120 tested VinV configurations.
• Internal orifice diameter (IOD) was the primary determinant of effective orifice area and regurgitant fraction; IOD < 22 mm increased stenosis risk, especially with >20% oversizing, while IOD > 23 mm with <8% oversizing increased paravalvular regurgitation risk.

Conclusions:

• The valve-in-valve procedure in mitral surgical bioprostheses generally yields satisfactory hemodynamic results.
• Significant mitral stenosis risk increases with a surgical bioprosthesis IOD < 22 mm, particularly with >20% oversizing.
• Significant paravalvular regurgitation is infrequent, associated with larger IODs and <8% oversizing.