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Randomized controlled trial of stented and stentless aortic bioprotheses: hemodynamic performance at 3 years
R J Williams1, D F Muir, V Pathi
1Department of Cardiothoracic Surgery and Cardiology, The Western Infirmary, Glasgow, Scotland.
Insights
The Toronto SPV stentless bioprosthesis offers superior hemodynamic performance and better left ventricular mass regression compared to the Carpentier Edwards SAV bioprosthesis after aortic valve replacement. This stentless valve allows for larger implantation and lower transvalvular gradients.
Area of Science:
- Cardiovascular Surgery
- Biomedical Engineering
- Cardiac Valve Replacement
Background:
- Aortic valve replacement is a critical procedure for managing aortic valve disease.
- Bioprosthetic valves are commonly used, but their long-term performance and impact on cardiac remodeling are areas of ongoing research.
- Comparing stentless versus stented bioprostheses is important for optimizing patient outcomes.
Purpose of the Study:
- To compare the hemodynamic performance of the Toronto SPV stentless bioprosthesis and the Carpentier Edwards SAV (CE) stented bioprosthesis.
- To evaluate left ventricular mass regression following aortic valve replacement with these two types of bioprostheses.
- To assess the feasibility of implanting larger valves in a given aortic annulus size with the stentless option.
Main Methods:
- A randomized prospective trial involving 40 patients undergoing aortic valve replacement.
- Hemodynamic measurements using thermodilution cardiac output catheter and echocardiography.
- Left ventricular mass assessment via magnetic resonance imaging (MRI) at baseline, 6 months, and 32 months.
Main Results:
- The stentless group allowed implantation of a larger valve (mean diameter 3 mm larger).
- Superior transvalvular gradients were observed in the stentless group at 1 week and maintained at 32 months.
- Significantly greater regression of left ventricular mass was observed in the stentless group at 32 months (diastole: 38% vs. 20%; systole: 23% vs. 13%).
Conclusions:
- A larger stentless aortic valve can be implanted into a given aortic annulus size, resulting in superior residual aortic valve gradients.
- Lower transvalvular gradients associated with the stentless bioprosthesis appear to promote improved long-term regression of left ventricular mass.
- The Toronto SPV stentless bioprosthesis demonstrates favorable hemodynamic performance and ventricular remodeling benefits compared to the CE stented bioprosthesis.
Abstract:
A randomized prospective trial was undertaken to compare the hemodynamic performance and left ventricular regression after aortic valve replacement with the Toronto SPV stentless bioprosthesis and the Carpentier Edwards SAV (CE) bioprosthesis. Forty patients were randomized after the annular and sinotubular diameters had been measured. Early hemodynamic measurements were made with a thermodilution cardiac output catheter, and echocardiography was used thereafter. Left ventricular mass was assessed using magnetic resonance imaging (MRI) at 1 week, 6 months, and 32 months. The mean annular size was 25.3+/-2.2 mm (CE) and 25.5+/-1.5 mm (Toronto), although it was possible to implant valves with a mean diameter 3 mm larger in the stentless group (26.0+/-1.7 mm cf. 23.0+/-1.7 mm). Hemodynamic performance in the first 24 hours showed no significant difference between the groups, but there was a trend for shorter ventilation time and shorter stays in the intensive therapy unit in the stentless group. Echocardiography showed superior transvalvular gradients in the stentless group at 1 week (mean 5.5+/-3.1 mm Hg cf. 8.9+/-2.5 mm Hg), and this difference was maintained at a mean follow-up time of 32 months (3.5+/-0.6 mm Hg cf. 6.3+/-0.6 mm Hg). Similar regression of left ventricular mass was seen in both groups at 6 months, but at 32 months, measurement in diastole showed a reduction of 38% (P<.01) in the stentless group compared with 20% (P = ns) in the stented group, and measurements in systole showed a 23% (P<.01) and 13% (P = ns) reduction, respectively. This study confirms that a larger stentless valve can be implanted into a given size of aortic annulus with superior residual aortic valve gradients. These lower gradients seem to result in improved long-term regression of left ventricular mass as measured by MRI.