SAT-498 - Rethinking Preoperative Alpha-Blockade: Prolonged Treatment Increases Intraoperative Hypertensive Crisis in Pheochromocytoma Surgery - A Retrospective Cohort Study

Background:
Hypertensive crisis remains a major intraoperative complication during pheochromocytoma surgery and frequently requires urgent pharmacological intervention. To minimize this risk, preoperative α-adrenergic blockade is routinely recommended. While previous studies have focused primarily on the choice of α-blocker, the effects of blockade duration, selectivity, and final titrated dose on the occurrence and severity of hypertensive crisis remain incompletely defined.

Methods:
We conducted a retrospective cohort study of 110 patients undergoing laparoscopic adrenalectomy for pheochromocytoma. The type of α-adrenergic blockade (doxazosin [DOX] vs phenoxybenzamine [PXB]), duration of preoperative preparation, and final titrated dose were analysed in relation to the risk and duration of intraoperative hypertensive crisis, defined as systolic blood pressure exceeding 200 mmHg.

Results:
In the overall cohort, longer duration of preoperative α-adrenergic blockade was positively associated with greater intraoperative blood pressure instability. Specifically, the length of preoperative preparation correlated with the number of systolic blood pressure episodes exceeding 160 mmHg (p=0.03) and with the cumulative duration of hypertensive crisis (ρ=0.77, p< 0.01). In multivariable analysis, diabetes mellitus, urinary metanephrine concentrations > 10x upper limit of normal, and preoperative α-blockade lasting longer than 30 days were identified as independent risk factors for intraoperative hypertensive crisis (OR 3.22, 95% CI 1.22–8.51, p=0.018). The final titrated dose of α-blocker was not associated with hypertensive outcomes.
When stratified by α-blocker type, the overall duration of hypertensive crisis was significantly longer in patients treated with doxazosin compared with phenoxybenzamine (median 15.0 [10.0–30.0] vs 10.0 [5.0–15.0] minutes, p=0.03). Patients receiving doxazosin more frequently required intraoperative vasopressor support and experienced longer perioperative hospitalization than those treated with phenoxybenzamine.

Conclusions:
Longer preoperative α-adrenergic blockade was associated with increased intraoperative blood pressure instability and a higher risk of hypertensive crisis, particularly when preparation exceeded 30 days. Selective α-blockade with doxazosin was linked to prolonged hypertensive crises, greater intraoperative vasopressor requirements, and longer hospitalization. These findings suggest that extending the duration of preoperative α-blockade does not improve intraoperative hemodynamic control in pheochromocytoma surgery.

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