Preoperative Metyrosine Improves Cardiovascular Outcomes for Patients Undergoing Surgery for Pheochromocytoma and Paraganglioma.

BACKGROUND: The goal of preoperative pharmacotherapy for pheochromocytoma (PCC) and paraganglioma (PGL) resection is to minimize intraoperative hemodynamic instability and perioperative cardiovascular complications, but no standard preoperative regimen exists. Historically, treatment used metyrosine and phenoxybenzamine (MP). The recent metyrosine shortage required that phenoxybenzamine alone (PA) be used for treatment. The authors examined their experience to determine the impact of preoperative metyrosine treatment on patient outcomes.

METHODS: A retrospective cohort study investigated patients who underwent initial PCC/PGL resection (2000-2014). The primary outcome was intraoperative hemodynamics, measured by heart rate (HR) and systolic blood pressure (SBP). The secondary outcomes included perioperative complications and cardiovascular-specific complications (CVC). Univariate analysis was performed, and adjusted risk differences were estimated after confounding was taken into account.

RESULTS: Of 174 patients, 142 (81.6 %) were in the MP group. The MP and PA patients had comparable intraoperative use of antihypertensives (83.9 vs 78.1 %; p = 0.443), vasopressors (74.6 vs 87.5 %; p = 0.120), and fluid resuscitation (mean, 24.4 vs 24.8 ml/min; p = 0.761). Although the perioperative complication rate did not differ significantly between the MP and PA groups (respectively 23.4 vs 34.4 %; p = 0.198), the PA patients had a 15.8 % higher rate of CVC even after controlling for confounders (p = 0.034). Compared with the MP patients, the PA patients had significantly more hemodynamic instability intraoperatively, with a greater range in HR (7.4 bpm; p = 0.034) and SBP (14.8 mmHg; p = 0.020).

CONCLUSIONS: In this study, preoperative metyrosine improved intraoperative hemodynamic stability and decreased CVC rates in patients undergoing PCC/PGLresection. These data suggest that the addition of preoperative metyrosine may improve operative outcomes.