Utility of oral nicardipine and magnesium sulfate infusion during preparation and resection of pheochromocytomas

Abstract

Calcium channel blockade with nicardipine (NC) is an alternative to phenoxybenzamine (PB) preparation for resection of a pheochromocytoma. Intraoperative magnesium sulfate infusion (+MgSO(4)) is often used for its cardiovascular stabilizing properties. We hypothesized that preparation with NC would be similar clinically to PB for resection of a pheochromocytoma, and MgSO(4) infusion would not affect intraoperative stability. This retrospective review included 64 patients undergoing resections of a pheochromocytoma from 2003 to 2011. PB or NC was used preoperatively, with MgSO(4) use distributed equally in the population. Pre-, intra-, and postoperative hemodynamics and outcomes were compared. There was no difference in NC (n = 7) versus PB (n = 57) or +MgSO(4) (n = 33) versus -MgSO(4) (n = 31) groups for demographics with the exception of age. The NC group had smaller median tumor size and lesser plasma baseline levels of normetanephrine than the PB group, but subgroup analysis of all neoplasms <3.0 cm revealed no differences. Pre-, intra- and postoperative hemodynamic stability and outcomes were similar for NC versus PB analyses as well as the +MgSO(4) versus -MgSO(4) groups. NC use may be an equivalent alternative to PB in preoperative preparation, especially for smaller pheochromocytomas. Intraoperative MgSO(4) use does not seem to have a substantive effect on hemodynamic stability.