Original ResearchPerioperative hemodynamics and outcomes of patients on metyrosine undergoing resection of pheochromocytoma or paraganglioma

- Metyrosine, a catecholamine synthesis inhibitor, is an expensive treatment used before resection of pheochromocytoma.
- Does this profound adrenergic blockade affect perioperative hemodynamic instability, and consequently outcomes?
- Due to availability of large number of patients in the Mayo Clinic Pheochromocytoma Registry we explore these outcomes.
- Postoperative outcomes were similar between patients who received metyrosine vs other less expensive adrenergic blockers.

IntroductionTo describe outcomes of patients with metyrosine (MET) pretreatment for abdominal surgical resection of pheochromocytoma or paraganglioma (PCC/PGL) compared with patients who had phenoxybenzamine (PBZ) pretreatment.MethodsRetrospective review of perioperative outcomes for PCC/PGL patients treated with MET and propensity-matched comparison of MET and PBZ (MET + PBZ) with PBZ alone.ResultsMET preparation was given in 63 cases (26 laparoscopic and 37 open, of which 55 also received PBZ). All patients had wide perioperative hemodynamic oscillations. Patients with open procedures required more intravenous fluids and blood transfusions; 35% required postoperative vasopressor infusions for hypotension and 38% developed acute kidney injury. One laparoscopic procedure required postoperative vasopressor infusion, and 12% of patients developed acute kidney injury. Forty-five MET + PBZ patients were propensity-matched with PBZ-only patients. Intraoperatively, MET + PBZ patients had lower minimum systolic and diastolic blood pressures than PBZ-only patients (median systolic, 74 vs 80 mm Hg, P = 0.01; median diastolic, 42 vs 46 mm Hg, P = 0.005) and larger intraoperative blood pressure oscillations (median systolic range, 112 vs 93 mm Hg, P = 0.06; median diastolic range, 58 vs 51 mm Hg, P = 0.02). Postoperative vasopressor infusion use was similar between MET + PBZ and PBZ only (16% vs 11%, P = 0.76). Major outcomes were not different between regimens.ConclusionLarge hemodynamic oscillations were present in our PCC/PGL patients treated with MET + PBZ. These patients had a wider range of intraoperative blood pressure variations than PBZ-only patients. No differences in postoperative comorbid outcomes were found between MET + PBZ and PBZ-only groups.