EVALUATION OF AORTIC-STENOSIS BY CONTINUOUS WAVE DOPPLER ULTRASOUND

[摘要] Patients (24) with suspected aortic stenosis (group I) were evaluated noninvasively by continuos wave Doppler ultrasound before undergoing cardiac catheterization. Normal subjects (20) served as the control group (group II). Maximal velocity measurements in the ascending aorta ranged from 3.0 to 5.8 m/s (mean 4.34 .+-. 0.65) in group I vs. 1.0 to 1.6 m/s (mean 1.28 .+-. 0.16) in group II (P < 0.001). Using the Bernoulli equation, the peak pressure gradient across the aortic valve was calculated from the maximal velocity in the group I patients. The results correlated well with the peak aortic valve gradient obtained at cardiac catheterization (r = 0.79). In 20 of these 24 patients, the peak Doppler gradient was within 25% of the gradient found at cardiac catheterization. In 3 patients, the Doppler study underestimated the gradient by slightly > 25% but still detected the presence of significant aortic stenosis. The Doppler technique failed to detect critical aortic stenosis in only 1 patient. Significant overestimation of the gradient by Doppler measurement did not occur in any patient. The technique was particularly helpful in older patients in whom other noninvasive tests often yield inconclusive results. An important but infrequent limitation of the technique is underestimation of the gradient that occurs when the angle of incidence between the ultrasound beam and aortic blood flow is too large. Continuous wave Doppler ultrasound apparently provides a reliable estimate of the valvular gradient in most patients with aortic stenosis.