Noninvasive assessment of portal hypertension shows promise
Virtual hepatic venous pressure gradient (vHVPG), a novel noninvasive approach to assess portal hypertension, is shown to correlate well with the gold-standard invasive method in a recent Chinese study.
“Measurement of hepatic venous pressure gradient [HVPG] is currently the standard method to assess portal hypertension. It is measured by means of catheterization of the hepatic vein with a balloon catheter, which is invasive and expensive with a high technical requirement,” explained investigator Dr Yanna Liu of the Southern Medical University, Guangzhou, Guangdong, China. “International liver associations such as the European Association for the Study of the Liver [EASL] and the American Association for the Study of Liver Diseases [AASLD] have therefore called for alternative tests to assess portal hypertension.” [J Hepatol 2015;63:743-752; Hepatology 2017;65:310-335]
Between August 2016 and April 2017, Liu and colleagues conducted the prospective CHESS-1601 study to evaluate the performance of noninvasive vHVPG in diagnosing clinically significant portal hypertension (CSPH) in 102 patients with compensated cirrhosis. Among these patients, 81.4 percent were confirmed to have CSPH by direct HVPG measurement. [https://clinicaltrials.gov/ct2/show/NCT02842697]
Results showed that vHVPG had an area under the curve of 0.88, sensitivity of 76 percent, and specificity of 90 percent in diagnosing CSPH.
The diagnostic performance of vHVPG was also better than that of other noninvasive models such as FibroScan, HVPGCT score and measurement of portal diameter. “However, the results require further validation as the current sample size is small,” said Liu.
“Portal hypertension is frequently observed in patients with cirrhosis, and is associated with a number of life-threatening complications. CSPH, defined as HVPG ≥10 mm Hg, is the strongest predictor of liver decompensation and hepatocellular carcinoma,” she explained.
“vHVPG is a novel approach combining an individual’s anatomical structure and haemodynamic changes, which allows direct simulation of HVPG,” Liu continued. “vHVPG is determined via construction of a three-dimensional hepatic vein-portal vein model with CT angiography images, followed by measurement of portal vein velocity with doppler ultrasound.”
She also emphasized the importance of obtaining quality CT images in improving the diagnostic accuracy of vHVPG.
“In our study, many cases were excluded from analysis due to poor CT image quality,” noted Liu. “Meanwhile, the correlation between vHVPG and HVPG was found to improve further in our exploratory analysis that included patients with CT images of moderate-to-excellent quality [n=50] only. In this group of patients, 66 percent were accurately classified as having CSPH, while only 8 percent were misclassified.”
“Our results suggest that vHVPG can act as a surrogate for invasive HVPG as the two methods correlated well with each other in diagnosing CSPH in cirrhotic patients,” she concluded. “However, the diagnostic performance of vHVPG should be further validated in larger cohorts of non-CSPH cases, since most of the patients [81.4 percent] in our study had CSPH as confirmed by HVPG.”
Liu received the runner-up prize of the 2017 International Digestive Disease Forum Young Investigator’s Awards for her present work.