The mean pressure difference across the valve in aortic stenosis is an indicator of the severity of the obstruction to flow. Non-invasive determination of the mean pressure gradient by Doppler ultrasonography is, however, complicated by the squared relation between instantaneous velocities and pressure differences. The validity of a new simple formula for calculation of the mean pressure difference from the peak pressure difference was evaluated in 26 patients with aortic stenosis. The formula is: Δpmean = 0·64 Δpmean, where Δpmean is the mean pressure gradient and LlPpeak the peak pressure gradient. There was a close correlation between the mean pressure differences determined by application of the formula to the peak pressure differences measured at catheterisation and the mean pressure differences obtained by planimetry (r = 0·97, SEE = 4·7 mmHg). The correlation between mean pressure differences determined by continuous wave Doppler ultrasound and the formula and those measured by planimetry was also close (r = 0·91, SEE = 7·6 mmHg) and only three patients showed a difference between the two methods of >10mmHg. The new formula is a simple and reliable means of estimating the mean pressure difference from Doppler recordings and it facilitates the comparison of Doppler and catheterisation data.
CITATION STYLE
Teien, D., Karp, K., & Eriksson, P. (1986). Non-invasive estimation of the mean pressure difference in aortic stenosis by Doppler ultrasound. Heart, 56(5), 450–454. https://doi.org/10.1136/hrt.56.5.450
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