Selective Arterial Calcium Stimulation With Hepatic Venous Sampling in Immune-Mediated Hypoglycemia

The purpose of the current study was to review the biochemical results of selective arterial calcium stimulation (SACST) with hepatic venous sampling in patients with immune-mediated hyperinsulinemic hypoglycemia. A retrospective review was undertaken of four patients with immune-mediated hyperinsulinemic hypoglycemia who underwent SACST with hepatic venous sampling from January 1996 to March 2014. Baseline systemic arterial and hepatic venous insulin concentrations (uIU/mL) were compared, and the absolute and relative-fold increase in hepatic venous insulin concentration after calcium stimulation was calculated. Baseline systemic arterial and hepatic venous insulin concentrations were elevated in all vessels sampled (range, 95 to 1704 uIU/mL), and there was no increase in the absolute or relative (1.0- to 1.3-fold) hepatic venous insulin concentration after calcium injection into any vessel. These data suggest that there are distinct biochemical responses to SACST in patients with immune-mediated hyperinsulinemic hypoglycemia compared with patients with endogenous, pancreatic-mediated hypoglycemia, such as insulinoma or nesidioblastosis.