EDITORIAL COMMENT Stenosis Is in the Eye of the Observer: Impact of Pressure Recovery on Assessing Aortic Valve Area*

Severity of aortic stenosis. The study by Garcia et al. (1) in this issue of the Journal has bearing on a long-standing clinical quandary: Doppler continuity aortic valve areas (2,3), taken in the context of typical catheterization valve area cutoff values (4,5), often appear to produce misclassi-fication toward higher degrees of severity, particularly in patients with relatively mild obstruction (6–8). Several technical factors may produce apparent area overestimation, such as the assumption of a uniform subvalvular velocity profile in the Doppler calculation. This study, however, shows that an independent cause of Doppler–catheter discrepancy is pressure recovery, a real physical phenomenon. See page 435 Pressure recovery. There has been a growing awareness that the simplified Bernoulli equation applied to Dopple