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Discrepancy of sizers for conventional and stentless aortic valve implants
Background And Aim Of The Study:
As the hemodynamic performance of an artificial heart valve is closely related to the size of the valve implanted, exact sizing of the prosthesis is important in aortic valve replacement. In the past, discrepancies have been recognized between the actual and labeled diameters of sizers used for conventional aortic valves; this study aimed to examine the accuracy of sizers for both conventional and stentless valves.
Methods:
Currently used sets of sizers were analyzed using a high-precision digital micrometer with a resolution of 0.01 mm. Sizers of aortic bileaflet mechanical valves (ATS, CarboMedics, St. Jude Medical Standard, St. Jude Medical HP), conventional aortic bioprostheses (Carpentier Edwards) and stentless aortic bioprostheses (Freestyle, TorontoSPV) were analyzed. The diameters were recorded when the sizer could not be moved laterally while still able to be rotated.
Results:
Results are given as mean +/- standard deviation for 20 repeat measurements. All mechanical valve sizers were 0.77 +/- 0.03 to 1.01 +/- 0.02 mm larger than labeled, whereas all bioprosthetic valve sizers proved to be sized as labeled (0 +/- 0.01 mm).
Conclusions:
Exact sizing is important in stentless valve replacement. The use of accurate sizers is recommended with other types of replacement valves as well. Results of valve replacement procedures worldwide would be more comparable if sizers of identical size were available in all operating rooms. As long as discrepancies between different sizers still exist, surgeons must be made aware of the problem.