Effectiveness and Safety of Outpatient Alpha and Beta Blockade Titration Protocol in Pheochromocytoma

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 37-82-Pheochromocytoma & Paraganglioma
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-61
Catherine Ann Barrett*, Daryl Gray, Christopher Harle, Stephen Pautler and Stan Van Uum
Western University, London, ON, Canada
BACKGROUND: Pheochromocytomas and paragangliomas are rare catecholamine secreting tumors. Surgery is the mainstay of treatment but carries a significant risk of triggering a hypertensive crisis or cardiac arrhythmia through the release of catecholamines by the tumor. Pre-operative blockade is recommended but regimens vary and have not been evaluated for the outpatient setting.

OBJECTIVES: To evaluate the safety and efficacy of an outpatient titration protocol using phenoxybenzamine and propranolol for the pre-operative preparation of patients with pheochromocytoma.

PATIENTS AND METHODS: We identified all patients with a pheochromocytoma or paraganglioma who received pre-treatment according to our protocol from 2004 to 2012. Patients were treated with phenoxybenzamine and propranolol for 10-14 days prior to their scheduled surgery date. Phenoxybenzamine was started at 10mg OD and propranolol at 40mg BID and titrated to a target dose of 30mg TID and 40mg QID respectively. Patients measured blood pressure and heart rate (supine and standing) using an automated home blood pressure device in the morning and evening and body weight daily. Results were phoned in or faxed to the office 2-3 times per week. We monitored the effects on mean arterial pressure (MAP), heart rate, weight and side effects, and analyzed peri-operative hemodynamics.

RESULTS: We included 13 patients (7M6F), mean age 45±16 years, 11 pheochromocytoma and 2 paraganglioma. The final daily doses of phenoxybenzamine and propranolol were 88±14 and 165±42mg. Supine MAP was 99±12 versus 92±13mmHg (P=0.12 paired student T-test), standing MAP was 99±12 versus 82±12mmHg (P=0.01) and weight was 81± 18 and 82±19kg (P=0.03) for baseline and end of titration parameters. Intra-operatively, 9 patients experienced hypertension (SBP>160mmHg) and 5 patients experienced hypotension (MAP<60mmHg). Two patients with very large tumors, maximum diameter 10 and 15cm had major blood pressure swings during surgery. No patient experienced sequelae of the blood pressure swings.

CONCLUSIONS: In this small retrospective study, outpatient pre-treatment with phenoxybenzamine and propranolol is safe when closely monitored and doses individually adjusted. It does not completely prevent intraoperative blood pressure variations which were primarily found in patients with large tumors. Confirmation of results in a prospective study potentially including both short and long acting alpha blockers is needed. 

Disclosure: SP: Speaker, Astra Zeneca, Research Funding, Palladin labs , Research Funding, Sanofi. Nothing to Disclose: CAB, DG, CH, SV

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm