Limitations and pitfalls in the assessment of prosthetic valves with Doppler ultrasonography.

Normal Doppler-derived data for new prosthetic designs are currently gathered after marketing. Therefore the cardiologist needing to assess a new valve may need to equate Doppler results with data gathered invasively during premarket testing. This invites error because catheterization and Doppler ultrasonography are not always directly comparable. This review discusses difficulties in defining normal prosthetic function and problems arising from the comparison of catheter and Doppler data. It concludes that (1) the hemodynamic formulas in current use have limitations when applied to normally functioning prosthetic valves, (2) patterns of normal regurgitation differ widely between different valve designs and may occasionally resemble paraprosthetic leaks, (3) there is a good case for reporting only raw Doppler data rather than derived pressure drop or effective orifice area, (4) a new prosthetic design should be tested in vivo with Doppler ultrasonography before marketing, and (5) nonprosthetic factors affecting Doppler data and flow information should always be given.