4:21 PMAbstract No. 355 - Selective arterial calcium stimulation (SACST) with hepatic venous sampling in patients with non-pancreatic mediated hyperinsulinemic hypoglycemia

Abstract

To review the biochemical results of selective arterial calcium stimulation (SACST) with hepatic venous sampling in patients with non-pancreatic mediated hyperinsulinemic hypoglycemia An IRB-approved, HIPAA-compliant retrospective review was undertaken of 9 patients with hyperinsulinemic hypoglycemia who underwent SACST with hepatic venous sampling from 1/1996 to 3/2014 and were later diagnosed with autoimmune or factitial hypoglycemia. 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 calculated. In 4 patients with autoimmune hypoglycemia, both baseline systemic arterial and hepatic venous insulin concentrations were elevated in all vessels sampled (range, 95-1704 uIU/ml) and there was no increase in the hepatic venous insulin concentration following calcium injection into any vessel (1.0 -1.2-fold). In patients with insulin (N=3) or sulfonylurea (N=2) factitial hypoglycemia, the baseline systemic arterial insulin concentration exceeded the hepatic venous insulin concentration in one or more vessels (1.1- 3.6-fold) and there was little to no increase in the absolute or relative hepatic venous insulin concentration over baseline following calcium injection in 4 of 5 patients (1.1 to 2.3-fold) while one patient with factitial insulin hypoglycemia had an increase in insulin concentration from 2.1 to 37 uIU/ml (17.6-fold) following calcium injection. In patients undergoing SACST, high baseline systemic arterial and hepatic venous insulin concentrations in all vessels without an increase in hepatic venous insulin concentration following calcium injection may suggest autoimmune hypoglycemia. Alternatively, higher baseline systemic arterial compared to hepatic venous insulin concentrations with minimal to no increase in absolute hepatic venous insulin concentration following calcium injection may raise concern for factitial hypoglycemia and the relative-fold increase in hepatic venous insulin concentration in these patients may not be reliable, particularly with a low baseline hepatic venous insulin concentration.