Fontan-Associated Dyslipidemia

Background Hypocholesterolemia is a marker of liver disease, and patients with a Fontan circulation may have hypocholesterolemia secondary to Fontan-associated liver disease or inflammation. We investigated circulating lipids in adults with a Fontan circulation and assessed the associations with clinical characteristics and adverse events. Methods and Results We enrolled 164 outpatients with a Fontan circulation, aged ≥18 years, in the Boston Adult Congenital Heart Disease Biobank and compared them with 81 healthy controls. The outcome was a combined outcome of nonelective cardiovascular hospitalization or death. Participants with a Fontan (median age, 30.3 [interquartile range, 22.8-34.3 years], 42% women) had lower total cholesterol (149.0±30.1 mg/dL versus 190.8±41.4 mg/dL, P<0.0001), low-density lipoprotein cholesterol (82.5±25.4 mg/dL versus 102.0±34.7 mg/dL, P<0.0001), and high-density lipoprotein cholesterol (42.8±12.2 mg/dL versus 64.1±16.9 mg/dL, P<0.0001) than controls. In those with a Fontan, high-density lipoprotein cholesterol was inversely correlated with body mass index (r=-0.30, P<0.0001), high-sensitivity C-reactive protein (r=-0.27, P=0.0006), and alanine aminotransferase (r=-0.18, P=0.02) but not with other liver disease markers. Lower high-density lipoprotein cholesterol was independently associated with greater hazard for the combined outcome adjusting for age, sex, body mass index, and functional class (hazard ratio [HR] per decrease of 10 mg/dL, 1.37; 95% CI, 1.04-1.81 [P=0.03]). This relationship was attenuated when log high-sensitivity C-reactive protein was added to the model (HR, 1.26; 95% CI, 0.95-1.67 [P=0.10]). Total cholesterol, low-density lipoprotein cholesterol, and triglycerides were not associated with the combined outcome. Conclusions The Fontan circulation is associated with decreased cholesterol levels, and lower high-density lipoprotein cholesterol is associated with adverse outcomes. This association may be driven by inflammation. Further studies are needed to understand the relationship between the severity of Fontan-associated liver disease and lipid metabolism.