Changing waveform during respiration on hepatic vein Doppler sonography of severe portal hypertension: comparison with the damping index.

OBJECTIVES

The purposes of this study were to assess retrospectively whether the waveform change during respiration on hepatic vein Doppler sonography is a parameter of severe portal hypertension as estimated by the hepatic venous pressure gradient (HVPG) and to compare with a hepatic vein damping index (DI) at expiration.

METHODS

Spectral Doppler sonography of the hepatic vein was performed on 22 consecutive patients who underwent HVPG measurement for portal hypertension with liver cirrhosis. From the maximum and minimum velocities of systolic hepatofugal venous flow on Doppler sonography, 3 parameters were derived: damping index at expiration (DI(exp)), damping index ratio (DI(ratio)), and damping index difference (ΔDI) between inspiration and expiration. Considering an HVPG level of 12 mm Hg or higher as the threshold level for high-grade portal hypertension, we assessed the diagnostic capability of these Doppler sonographic parameters to discriminate using receiver operating characteristic curve analysis.

RESULTS

Area under the curve values for the DI(ratio) and ΔDI (0.875 and 0.889, P = .807 and .682, respectively) were slightly higher than the area for the DI(exp) (0.861; respectively). When the DI(exp) was greater than 0.56, the sensitivity and specificity for high-grade portal hypertension were 66.7% and 100.0%, respectively. In the case of the DI(ratio), the sensitivity and specificity were 77.8%, and 100.0% at greater than 0.69. The corresponding sensitivity and specificity at a value of 0.25 or less for the ΔDI were 83.3% and 100.0%.

CONCLUSIONS

The ratio and difference of the DI of the hepatic vein waveform are helpful parameters in assessing the severity of portal hypertension as well as using the existing DI on its own.