Evaluation of regional hepatic perfusion (RHP) by contrast-enhanced ultrasound in patients with cirrhosis

Abstract

Background & aims: Ultrasonographic contrast agents allow the assessment of myocardial and renal perfusion through the analysis of refill kinetics after microbubbles rupture. This study evaluated the feasibility of contrast-enhanced ultrasonographic (CEUS) estimations of regional hepatic perfusion in patients with cirrhosis, and its correlation with clinical and hemodynamic parameters.

Methods: Fifty-five patients with cirrhosis undergoing hepatic vein catheterization were included. Hepatic perfusion was studied by CEUS (using Contrast Coherent Imaging) during a continuous i.v. infusion of microbubbles (SonoVue®); after their rupture (high insonation power), tissue refill was digitally recorded and time-intensity curves were electronically calculated on a region of interest of the right hepatic lobe. Regional hepatic perfusion (RHP) was calculated as microbubbles velocity×microbubble concentration. During hepatic vein catheterization, we measured hepatic blood flow by indocyanine green (ICG) infusion, hepatic venous pressure gradient (HVPG), and cardiac output (Swan-Ganz catheter).

Results: RHP was higher in patients than in healthy controls (5.1±3.7 vs. 3.4±0.7, p=0.003), and correlated with MELD (R=0.403, p=0.002), Child-Pugh score (R=0.348, p=0.009), and HVPG (R=0.279, p=0.041). RHP inversely correlated with ICG extraction (R=-0.346, p=0.039), ICG intrinsic clearance (R=-0.327, p=0.050), and ICG clearance (R=0.517, p=0.001), and directly correlated with hyperdynamic syndrome markers (cardiac index R=0.422, p=0.003; mean arterial pressure R=-0.405, p=0.004; systemic vascular resistance R=-0.496, p=0.001).

Conclusions: RHP increases in patients with cirrhosis and correlates with the degree of liver failure and hyperdynamic syndrome. RHP increases along with liver functional reserve decrease, suggesting that RHP increase occurs mainly through anatomical/functional shunts. RHP by CEUS is a feasible novel, objective, quantitative, non-invasive tool, potentially useful for the estimation of hepatic perfusion in patients with cirrhosis.