Elevated Serum Cobalamin in Patients With Decompensated Biventricular Failure

Background: Serum cobalamin (vitamin B-12), bound to transcobalamin 11, is taken up by the endothelium of the hepatic vasculature via a receptor-mediated membrane transport process. We hypothesized hepatic congestion is associated with elevated serum B-12 without hepatocyte necrosis. Methods and Results: Serum B-12, aspartate and alanine transaminases, alkaline phosphatase, bilirubin (Bili), and brain natriuretic peptide (BNP) were monitored at the time of admission in 91 hospitalized patients: (a) 38 with decompensated biventricular failure having systemic venous distention, tricuspid regurgitation (TR), and echocardiographic evidence of inferior vena cava dilation and moderate to marked TR; (b) 18 with acute left heart failure having a myocardial infarction, an ischernic cardiomyopathy, or hypertensive heart disease; and (c) 35 without clinical evidence of failure despite myocardial infarction, pericarditis, or atrial arrhythmia. Serum cobalamin (normal 180-600 pg/mL) was elevated with biventricular failure (861.4 +/- 53.0 pg/mL) compared with (P < 0.0001) left heart or no failure, where B12 remained normal. Serum aspartate, alanine, and alkaline phosphatase were normal in each group whereas Bili was increased (1.8 +/- 0.2 mg/dL; P < 0.05) with biventricular failure. Plasma BNP was elevated in each group. Conclusions: Elevated cobalamin and Bili are respective biomarkers of hepatocellular dysfunction and cholestasis in patients having decompensated biventricular failure with systemic venous distention and TR without hepatocyte necrosis vis-a-vis left heart failure or in the absence of clinical failure. Elevated plasma BNP did not distinguish between the presence or absence of systemic venous congestion.