Echocardiographic assessment of isolated pulmonary valve stenosis: which outpatient Doppler gradient has the most clinical validity?

Maximum instantaneous Doppler gradient has been the primary variable used to assess severity of pulmonary valve stenosis. However, recent observations suggest that outpatient maximum Doppler gradient often overstates clinical severity, as measured by catheter peak-to-peak gradient (PPG). This study sought to determine which outpatient Doppler gradient was most predictive of subsequently measured PPG. Ninety patients were included. Outpatient mean Doppler gradient showed the best correlation and agreement with the catheter PPG (r = 0.82, bias = -5 mm Hg). Maximum Doppler gradients, even when corrected for proximal velocity, consistently overestimated the PPG (bias = +21-26 mm Hg). Outpatient mean gradient was most predictive of subsequent PPG and should be used to determine whether to intervene for patients with isolated pulmonary valve stenosis. Use of only the maximum Doppler gradient to assess pulmonary valve stenosis will lead to a systematic overstatement of the severity of the stenosis.