CORRELATION OF DOPPLER-DERIVED GRADIENTS WITH CARDIAC-CATHETERIZATIONGRADIENTS IN SUPRAVALVULAR AORTIC-STENOSIS

The purpose of this study was to compare estimates for pressure gradie nts of supravalvular aortic stenosis derived from continuous wave Dopp ler ultrasound with gradients measured directly by catheterization. Pr essure gradients at rest (14 patients) and after exercise (nine patien ts) were measured by fluid-filled catheters placed proximally and dist ally to the stenosis. Doppler spectral signals were simultaneously obt ained using a 2.0 MHz nonimaging transducer in the suprasternal notch. Doppler and pressure recordings were analyzed to measure maximal inst antaneous, mean, midsystolic and peak-to-peak gradients. Maximal insta ntaneous Doppler gradient showed an excellent linear correlation with maximal instantaneous catheterization gradient (r = 0.97; SEE = 10.4 m mHg). The correlation of Doppler-estimated maximal gradient to peak-to -peak catheterization gradient was also linear (r = 0.93; SEE = 16 mmH g) but resulted in a systematic overestimation of the invasive peak-to -peak gradient (mean overestimation: 22 mmHg; SEM = 4.8 mmHg). Measure ment of the Doppler gradient at midsystole resulted in a better correl ation with the peak-to-peak catheterization gradient (r = 0.96, SEE = 10.6 mmHg) and a minor overestimation (mean overestimation: 10.7 mmHg; SEM = 3.1 mmHg). A good correlation was also seen between Doppler- an d catheterization-derived mean gradients (r = 0.96; SEE = 6.2 mmHg). A n excellent correlation was found between maximal instantaneous resp. mean Doppler- and maximal instantaneous resp. mean catheterization-der ived gradients after exercise (r = 0.96; SEE = 10.8 mmHg resp. r = 0.9 5, SEE = 6.5 mmHg). The results in this study suggest that pressure gr adients obtained from continuous wave Doppler ultrasound are accurate in predicting corresponding cardiac catheterization measurements.