Cardiopulmonary exercise testing in the evaluation of liver disease in adults who have had the Fontan operation

Summary Background Liver disease (LD) is a long-term complication in patients with a single ventricle who have had the Fontan operation. A decline in cardiopulmonary exercise testing (CPET) variables is associated with increased risk of hospitalization, but its association with LD is unknown. Aim To determine the association between CPET variables and LD in adults who have had the Fontan operation. Methods We retrospectively reviewed the medical records from two tertiary institutions. Results We identified 114 adults (≥ 18 years; mean 30.9 ± 7.4 years) who had undergone the Fontan operation: 56% were women; 63% had total cavopulmonary connection; 66% had New York Heart Association (NYHA) class I status; 42% had arrhythmias; 22% had systemic right ventricle; and 35% had ventricular dysfunction. Of 81 patients with liver-imaging data, 41% had LD (i.e. imaging evidence of cirrhosis, with or without portal hypertension, splenomegaly or varices). There were no differences in clinical or echocardiographic variables between those with and without LD. Among the 58 patients with CPET data, mean peak oxygen consumption (VO 2 ) was 18.6 ± 5.7 mL/kg/min, per-cent-predicted peak VO 2 was 53.9 ± 15.5%, peak oxygen pulse was 9.3 ± 2.9 mL/beat and per-cent-predicted peak oxygen pulse was 82.6 ± 21.5%. Of the 44 patients with liver and CPET data, each standard deviation decrease in per-cent-predicted peak VO 2 (16%) and per-cent-predicted peak oxygen pulse (22%) was associated with a 2.3-fold increase in the odds of LD, after adjusting for NYHA, institution and Fontan type ( P  = 0.04). Similarly, each standard deviation decrease in per-cent-predicted peak VO 2 and oxygen pulse was associated with an estimated 5.9-year and 4.9-year earlier onset of LD, respectively ( P  > 0.05). Conclusions Decline in per-cent-predicted peak VO 2 and oxygen pulse was associated with increased odds of LD in adults who had undergone the Fontan operation. Our study supports more rapid hepatic evaluation among patients with abnormal or worsening CPET variables.