Abstract 3107: Discrepancies Between Catheter and Doppler Estimates of Aortic Stenosis: the Role of Pressure Recovery Evaluated “in Vivo”
Background. Discrepancies are often observed between catheter and Doppler derived gradients and valve areas. The aim of this study is to verify if these can be attenuated by taking into account the pressure recovery.
Patients and Method. A total of 259 patients with aortic valve area < 2 cm2 were prospectively collected since Jan 1, 2000. During diagnostic catheterization, aortic valve gradient was taken as peak left ventricular pressure minus peak aortic pressure. Aortic valve area was calculated with Gorlin’s (AG). An echocardiogram was obtained within 15 days from this procedure . Transvalvular gradients were measured with Doppler technique, and aortic valve area (EOA) was computed with continuity equation. The diameter of ascending aorta was taken in parasternal long axis view, and ascending aorta sectional area (AA) was then computed according to geometric formulae. In order to correct for pressure recovery we used the energy loss coefficient equation (ELCO = (AA * EOA)/(AA - EOA)). Correlations between Gorlin’s area, continuity area and ELCO were evaluated by linear regression analysis. Since cardiac output affects the estimates of valve areas, we calculated the correlation separately for patients above and below the median cardiac index (CI) (2.7 l/m’/m2).
Results and Conclusions. A good linear correlation is present between AG and EOA with regression coefficient 0.88 independent of cardiac output. A better correlation is present between AG and ELCO, with regression coefficient , namely 0.99 with CI ≤ 2.7, and 0.94 with CI > 2.7. In conclusion, pressure recovery may cause discordance between EOA and AG. ELCO improves the correlation in different ranges of flow and valve area.