Hepatic Artery and Portal Vein Hemodynamics in Nonalcoholic Fatty Liver Disease in Adult Saudi Patients: A Doppler Ultrasound Study

Abstract

Background: Nonalcoholic fatty liver disease (NAFLD) is a growing public health problem. With the growing severity of NAFLD, there are considerable alterations in the hemodynamics of the hepatic circulation that might affect the prognosis of the condition, according to numerous reports written to assess the vasculature of the liver in patients affected with fatty liver disease. The aim of the study was to examine hemodynamic alterations in the hepatic artery (HA) and portal vein (PV) in NAFLD patients and determine how they relate to the severity of the condition, and to classify patients into various categories of NAFLD and connect the results to liver size and body mass index (BMI). Methods and Results: One hundred and six diagnosed NAFLD patients who attended the Imaging department at King Fahad Hospital from December 2019 to January 2020 were retrospectively studied. The mean age of the patients was 45.75±15.6 years, with a range of 10-79 years. The patients were examined by a TOSHIBA Xario, SSA-660A ultrasound system utilizing a multifrequency convex transducer (2–5 MHz) for all sonographic exams. B-mode assessed the liver parenchyma, and spectral Doppler estimated the HA and PV. The US appearance of hepatosteatosis, according to the severity of echogenicity, was graded (0-3). Most participants were asymptomatic (76.4%), and diabetes and diabetes with hypertension were diagnosed in 12.3% and 11.3%, respectively. It was observed that grade 1 hepatosteatosis was more prevalent than the other grades: 54 cases versus 41 cases for grade 2 and 11 cases for grade 3. The mean values of liver size and BMI in grade 3 were higher than in grade 1 (P=0.0033 and P=0.0054, respectively). A Spearman test found that the liver size (R=0.19, P=0.05) and BMI (R=0.26, P=0.01) had weak positive, but statistically significant, correlations with the severity of the hepatosteatosis grade. Doppler indices of the HA and PV in NAFLD patients did not differ significantly in hepatosteatosis grades 1-3. Only the PSV and EDV of the main PV showed a significant decrease in the hepatosteatosis grade 2 compared to grade 1 (P=0.0065 and P=0.0234, respectively). Despite the insignificant differences, the Doppler flow parameters of the HA decreased with the severity of hepatic steatosis; for example, the hepatic artery resistive index (HARI) was 0.77±0.16 in grade 1, 0.72±0.16 in grade 2, and 0.75±0.10 in grade 3, respectively. The hepatic artery pulsatility index (HAPI) was 1.62±49 in grade 1, 1.63±.68 in grade 2, and 1.74±0.77 in grade 3. There was also a trend toward a decrease in PSV and end-diastolic velocity (EDV) of HA with the severity of hepatosteatosis. Conclusion: The severity of hepatic steatosis is significantly correlated with liver size and BMI. The blood flow parameters of PV and HA decrease with the severity of hepatic steatosis except for the pulsatility index.