Brief Communication: Radiographic Contrast Infusion and Catecholamine Release in Patients With Pheochromocytoma

Background: Contrast-enhanced computed tomography (CT) is useful for localizing pheochromocytoma. However, in patients with suspected pheochromocytoma, CT is often canceled or not performed because of the strong belief that intravenous contrast may induce hypertensive crisis. Objective: To examine whether intravenous low-osmolar contrast administration during CT induces catecholamine release that increases blood pressure or heart rate. Design: Prospective study. Setting: Warren G. Magnuson Clinical Center, National Institutes of Health, Bethesda, Maryland. Participants: 22 patients with pheochromocytoma (15 nonadrenal and 7 adrenal) and 8 unmatched control participants without pheochromocytoma. Measurements: Plasma catecholamine levels, blood pressure, and heart rate. Results: Plasma catecholamine levels within and between groups did not significantly differ before and after intravenous administration of low-osmolar CT contrast. Patients with pheochromocytoma experienced a clinically and statistically significant increase in diastolic blood pressure that was not accompanied by corresponding increases in plasma catecholamine levels. The difference became non -statistically significant after adjustment for use of alpha-and beta-blockers. Limitation: The study lacked a placebo group, and the sample was relatively small. Conclusion: Intravenous low-osmolar contrast-enhanced CT can safely be used in patients with pheochromocytoma who are not receiving alpha-or beta-blockers.