PSAT008 Pheochromocytoma Management: Considerations for Cardiac Stress Testing

INTRODUCTION: Pheochromocytomas, though rare, can have dire consequences and should be treated with timely surgical resection. Left untreated, there is high risk for developing cardiomyopathy, hemorrhagic stroke, pulmonary edema, etc. However, the resection itself has a high risk for hemodynamic instability and cardiac complications. We present a case of pheochromocytoma in a patient with multiple comorbidities who required pre-op cardiac clearance and discuss the considerations for appropriate stress test selection. CASE: A 60-year-old male with PMH of HTN, T2DM, CKD, OSA, and PAD s/p bilateral LE amputations was incidentally found to have a 6×5×5cm left adrenal mass on CT A/P done after a motor vehicle accident. MRI confirmed 6.6cm left adrenal mass. Lab testing showed elevated plasma fractionated catecholamines with free metanephrines 2246 (<57 pg/mL), free normetanephrines 1014 (<148 pg/mL), total metanephrines 3260 (<4-fold ULN of MN+NMN), aldosterone 11 (<28 ng/dL), plasma renin activity 0.28 (0.25-5.82 ng/mL/h), post-DST cortisol 2.7 (<2.0 ng/dL; 2-10 is equivocal), and chromogranin A 1449 (<311 ng/mL). 24-hour urine showed metanephrines 4114 (90-315 mcg/24H), normetanephrines 1174 (122-676 mcg/24H), and total metanephrines 5288 (224-832 mcg/24H). I-123 MIBG scan confirmed suspicion for pheochromocytoma. BP was elevated despite doxazosin 4mg BID, lisinopril 20mg daily, amlodipine 10mg daily, and carvedilol 37.5mg BID. He was referred to urology who planned for surgical resection pending cardiac clearance. Cardiology requested stress test to assist with pre-op risk stratification given multiple cardiac risk factors. Exercise stress test was not possible due to h/o LE amputations. Dobutamine stress test was initially recommended as this is the default testing modality at our institution but after multi-disciplinary discussion, regadenoson stress test was later selected due to concern for catecholamine surge and pheochromocytoma crisis with dobutamine use. Stress test was completed without complications and showed small reversible perfusion defect. Cardiac clearance was obtained for semi-urgent surgery. Patient tolerated left adrenalectomy and pathology confirmed pheochromocytoma. BP is now well-controlled on carvedilol 25mg BID alone. DISCUSSION: Cardiac stress testing with an underlying pheochromocytoma requires thoughtful decision making. Case reports describe cardiogenic shock, hypertensive crisis, or even death after exercise or dobutamine stress testing, possibly secondary to catecholamine surge resulting in pheochromocytoma crisis. Dobutamine is a synthetic catecholamine that stimulates both β and α(1) receptors to increase inotropy and chronotropy, whereas regadenoson is a selective α2a receptor agonist that increases coronary vasodilation. In pheochromocytoma patients who require pre-op cardiac clearance, it is important to consider mechanism of action of various stress test modalities to avoid potential complications or consequent fatalities related to hemodynamic instability. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.