Comparison of eight prosthetic aortic valves in a cadaver model.

OBJECTIVES: Proper valve selection is critical to ensure appropriate valve replacement for patients, because implantation of a small valve might place the patient at risk for persistent gradients. Labeled valve size is not the same as millimeter measure of prosthetic valve diameters or the annulus into which it will fit. Studies that use the labeled valve size in lieu of actual measured diameter in millimeters to compare different valves might be misleading. Using human cadaver hearts, we sized the aortic annulus with 8 commonly used prosthetic aortic valve sizers and compared the valves using geometric orifice area. This novel method for comparing prosthetic valves allowed us to evaluate multiple valves for implantation into the same annulus.

METHODS: Aortic annular area was determined in 66 cadavers. Valve sizers for 8 prosthetic valves were used to determine the appropriate valve for aortic valve replacement. Regression analyses were performed to compare the relationship between geometric orifice area and aortic annular area.

RESULTS: Tissue valves had a larger orifice area for any annular size but were not different at small sizes. Supra-annular valves were larger than intra-annular valves for the small annulus, but this relationship was not uniform with increasing annular size.

CONCLUSIONS: Labeled valve size relates unpredictably to annular size and orifice area. No advantage in geometric orifice area could be demonstrated between these tissue valves at small annular sizes. Valves with the steepest slope on regression analysis might provide a larger benefit with upsizing with respect to geometric orifice area.