SUN-500 - Perioperative Hemodynamic Variability in Pheochromocytoma Resection: A Comparison between Selective and Nonselective Alpha Blockade

Introduction: Preoperative alpha‑adrenergic blockade is standard for pheochromocytoma (PCC) resection, but the optimal regimen remains debated. Traditional non‑selective blockade with phenoxybenzamine is increasingly replaced by selective α1‑blockers such as doxazosin due to cost, tolerance, and availability considerations. We compared perioperative outcomes between these approaches.


Methods: We performed a retrospective cohort study of 190 patients undergoing PCC resection between 2010–2025 who received ≥1 week of phenoxybenzamine or doxazosin. Primary outcomes included intraoperative hemodynamics, vasopressor and fluid requirements, ICU admission, and hospital length of stay (LOS).


Results: A total of N=190 patients were included, median age 53.8 years [42.9, 63.7], 60.5% (N=115) female, 77.9% (N=148) Caucasian, with median tumor size 4.0 cm [2.8, 5.6]. The median duration of alpha-blockade therapy was 30 days [25, 48]. Compared to those treated with phenoxybenzamine (N=129, 67.9%), those treated with doxazosin (N=61, 32.1%) were older (56.6 yrs [48.7, 66.8] vs. 51.0 [41.3, 62,3], p=0.027). There were no significant differences with respect to sex, ethnicity, tumor size, or biochemical phenotype. Hospital length of stay was slightly longer with doxazosin on univariable analysis (2 [1, 3] vs 1 [1, 2] day, p=0.008) and remained longer on multivariable analysis (adjusted increase 30.9%, 95% CI 8.6 to 57.9%, p=0.005). Intraoperative max heart rate (HR) was lower with doxazosin (100 [90, 110] vs. 110 [100, 120] bpm, p< 0.001), associated with an adjusted 9.5 bpm lower max HR (95% CI -15.0 to -4.1, p< 0.001). HR range was also lower with doxazosin (44 [32, 53] vs 50 [38, 62] bpm, p=0.008) (adjusted -8.4 bpm, 95% CI -14.5 to -2.2, p=0.008). There were no significant differences in ICU utilization, 90-day mortality, intraoperative IV fluid or vasopressor use, intraoperative MAP parameters or incidence of extreme hypertension (SBP≥190) or hypotension (SBP≤70) between groups.

Conclusion: Phenoxybenzamine and doxazosin provide comparable perioperative hemodynamic stability for patients undergoing PCC resection, with no significant differences in blood pressure excursions, vasopressor requirements, or ICU utilization. The lower maximum heart rate and narrower range observed with doxazosin likely reflect its selective alpha blockade, offering a potential clinical advantage in limiting reflex tachycardia without compromising blood pressure control. While doxazosin was associated with a statistically longer hospital LOS, the absolute difference remained small within the context of a brief median hospitalization. Overall, our data supports the safety and efficacy of either agent for preoperative preparation. Future prospective or multicenter studies are needed to confirm these associations and further explore cost and resource utilization.

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