Portal Vein Pulsatility Index as a Noninvasive Tool for Staging Nonalcoholic Fatty Liver Disease: A Case-Control...

Nonalcoholic fatty liver disease (NAFLD) causes progressive liver fibrosis and vascular remodeling. Portal vein pulsatility index (PVPI) has emerged as a potential ultrasound biomarker for high-risk NAFLD, but its relationship to other Doppler measures is not fully explored.

To evaluate PVPI as a noninvasive tool for staging NAFLD and to incorporate portal vein resistive index (RI) and peak systolic velocity (PSV) parameters for a more comprehensive assessment of hepatic vascular resistance.

We performed a case-control study of NAFLD patients (spanning mild steatosis to advanced fibrosis) and healthy controls. All subjects underwent duplex Doppler ultrasound. PVPI was calculated as [(Vmax - Vmin)/Vmean]. Simulated portal RI and PSV values for each NAFLD severity group were also derived. Key outcomes were compared across steatosis grades and fibrosis categories and correlated with fibrosis risk scores.

NAFLD patients had significantly lower PVPI than controls (p < 0.001), and PVPI decreased progressively with higher steatosis grade and fibrosis stage. High-risk NAFLD (significant fibrosis) showed a markedly reduced PVPI (mean ~0.20 vs. ~0.30 in low-risk) alongside a decline in portal RI and PSV. For example, portal PSV dropped from ~13 cm/s in mild NAFLD to ~10 cm/s in advanced fibrosis. PVPI correlated with fibrosis stage (r ~ -0.44), and adding RI/PSV helped delineate increases in hepatic vascular resistance.

Portal vein Doppler indices (PVPI, RI, PSV) worsen with NAFLD severity. PVPI, especially when complemented by RI and PSV, is a promising noninvasive marker for staging NAFLD and identifying high-fibrosis risk.