Background: Pheochromocytoma and paraganglioma (PPGL) are rare catecholamine-secreting tumors. Surgical resection of PPGL carries a risk of hemodynamic instability (HDI). Preoperative treatment with alpha blocker is known to reduce intraoperative HDI.
Objective: To determine predictive risk factors for intraoperative HDI in PPGL surgical resection.
Methods: This is a retrospective study of adult PPGL patients who underwent resection during 2003 - 2015. The patients' biochemical and imaging profiles, pre-, peri-, postoperative medical and anesthetic records were reviewed. The HDI included hypertensive, hypotensive, tachycardia, and bradycardia events.
Results: Seventy-four patients (64 pheochromocytoma, 10 paraganglioma) underwent 78 operations. Intraoperative HDI events occurred in 76 operations. Common HDI were hypertensive and hypotensive events (90%, 67% respectively). Rate of intraoperative vasodilator treatments were higher than vasopressor treatments (94%, 68% respectively). Significant hypertensive and hypotensive HDI ≥ 10 events, occurred in 11 operations, were associated with malignant PPGL by multivariate analysis (OR 8.1; P < 0.01). From subgroup analysis, tumor diameter correlated with hypertensive and tachycardia episodes (r 0.25; P 0.04, r 0.75; P < 0.01 respectively). Anemia at presentation was associated with hypertensive HDI (OR 3.2; P 0.02). Perioperative antihypertensive dose uptitration was associated with hypotensive HDI (OR 3.7; P 0.04). Beta blocker usage was associated with bradycardia and postoperative hypotension (OR 1.2; P 0.02, OR 2.9; P 0.03). Among alpha blocker types, prazosin usage was associated with more tachycardia events than doxazosin usage (OR 8.8; P <0.01).
Conclusion: Hemodynamic instability was common among PPGL resections, resulting in high rates of vasodilator and vasopressor usage. Malignant PPGL and larger tumors remained the common risk factors for HDI even after alpha blocker treatment. Anemia without evidence of bleeding and beta blocker usage were potentially risk factors for HDI. Types of alpha blockers may not be equally effective in preventing HDI. There was no 30-days mortality found.