Hepatic stiffness in the bidirectional cavopulmonary circulation: The Liver Adult-Pediatric-Congenital-Heart-Disease Dysfunction Study group

Abstract

Objectives: We hypothesized that hepatic injury in single-ventricle CHD has origins that predate the Fontan operation. We aimed to measure hepatic stiffness using ultrasound and shear wave elastography (SWE) in a bidirectional cavopulmonary connection (BCPC) cohort.

Methods: Subjects were prospectively recruited for real-time, hepatic, ultrasound-SWE for hepatic stiffness (kPa) and echocardiography. Doppler velocities, a velocity-time integral, flow volume, and resistive index, pulsatility index, and acceleration index were measured in celiac and superior mesenteric arteries, and in the main portal vein (MPV). Comparisons were made among subjects who had BCPC, subjects who were healthy, and a cohort of patients who had undergone the Fontan procedure.

Results: Forty subjects (20 patients who had BCPC; 20 age- and gender-matched control subjects) were studied. The hepatic stiffness in BCPC was elevated, compared with that in control subjects (7.2 vs 5.7 kPa; P = .039). Patients who had BCPC had significantly higher celiac artery resistive index (0.9 vs 0.8; P = .002); pulsatility index (2.2 vs 1.7; P = .002); and systolic-diastolic flow ratio (10.1 vs 5.9; P = .002), whereas the superior mesenteric artery acceleration index (796 vs 1419 mL/min in control subjects; P = .04) was lower. An elevated resistive index (0.42 vs 0.29; P = .002) and pulsatility index (0.55 vs 0.35; P = .001) were seen in MPV, whereas MPV flow was reduced (137.3 vs 215.7 mL/min in control subjects; P = .036). A significant correlation was found for hepatic stiffness with right atrial pressure obtained at catheterization (P = .002). Comparison with patients who underwent the Fontan procedure showed patients who had BCPC had lower hepatic stiffness (7.2 vs 15.6 kPa; P < .001).

Conclusions: Hepatic stiffness is increased with BCPC physiology, and this finding raises concerns that hepatopathology in palliated, single-ventricle CHD is not exclusively attributable to Fontan physiology. Hepatic stiffness measurements using SWE are feasible in this young population, and the technique shows promise as a means for monitoring disease progression.

Keywords: Fontan procedure; bidirectional cavopulmonary anastomosis; congenital heart disease; hepatic stiffness; shear wave elastography.