Elevated Serum Cobalamin in Patients With Decompensated Biventricular Failure

Abstract

Serum cobalamin (vitamin B12), bound to transcobalamin II, 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 B12 without hepatocyte necrosis. Serum B12, 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 ischemic 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. 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-à-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.