Journal: Anesth Analg 105(5):1192-1199, 2007. 21 References
Reprint: Dept of Anesthesiology, Mayo Clinic, 200 First St. SW, Rochester MN 55905 (MD Abel, MD)
Faculty Disclosure: Abstracted by J. Joyce, who has nothing to disclose.
Carcinoid tumors arise from enterochromaffin cells found in the small bowel. Tumor cells secrete an array of substances, including vasoactive amines such as serotonin, prostaglandins, and vasoactive peptides. The carcinoid syndrome occurs when these substances are secreted into the systemic venous system from a tumor metastasized to the liver or originating in the ovaries, lungs, or thyroid. Carcinoid crisis, characterized by flushing, hypotension, and bronchospasm, can be provoked pharmacologically by administration of epinephrine, norepinephrine, dopamine, isoproterenol, and calcium. Octreotide has been demonstrated to control intraoperative carcinoid symptoms.
Carcinoid valvular disease results from exposure of cardiac valves to chronically elevated plasma serotonin levels. These lesions are usually limited to right-sided valves, typically resulting in tricuspid and pulmonary valve regurgitation and stenosis. Left-sided cardiac involvement occurs in the presence of pulmonary tumors, right-to-left intracardiac shunts, or in the presence of overwhelming disease. Patients having cardiac surgery often require vasoactive medications to support the circulatory system. These medications might trigger carcinoid crises, and their intraoperative use may lead to more octreotide administration.
The aim of this study was to evaluate whether vasoactive medications used during cardiac surgery would provoke carcinoid activity resulting in an increased administration of octreotide. The authors further sought to evaluate whether use of aprotinin would attenuate carcinoid activity as demonstrated by less frequent use of octreotide. Finally, these authors analyzed whether octreotide and/or aprotinin usage impacted mortality.
The clinical introduction of octreotide has provided the anesthesiologist with an effective tool to manage manifestations of carcinoid activity. Octreotide controls carcinoid symptoms by inhibiting carcinoid tumor cells from secreting vasoactive peptides and amines into the circulation. In this study, the authors made the assumption that the total intraoperative octreotide dose was a reflection of carcinoid activity. This assumption is supported by the observation that patients not administered octreotide preoperatively were less likely to be administered octreotide intraoperatively, suggesting less carcinoid activity. Currently, there is no other quantitative measure of intraoperative carcinoid activity. Total intraoperative octreotide dose cannot be used as a surrogate measure for hemodynamic instability. Hemodynamic instability in these patients is multifactorial.
The fact that intraoperative octreotide administration did not vary with mortality suggests the cause of death was multifactorial. The majority of patients in this cohort received vasopressor medications. Catecholamines trigger carcinoid tumors to release a variety of substances that are responsible for the carcinoid crises. Intraoperative hypotension in these patients can be recalcitrant, or even paradoxically worsened by the administration of vasoactive medications, because these medications stimulate more carcinoid activity. Octreotide has become the therapy of choice for treating intraoperative hypotension in patients with carcinoid syndrome because it blocks the release of tumor-secreted substances. In this series, administration of catecholamine drugs was not associated with higher intraoperative octreotide dosages, suggesting their use did not result in increased carcinoid secretion.
The authors found that the use of aprotinin was associated with increased intraoperative octreotide dosages. Aprotinin use has been reported in patients with carcinoid syndrome to treat carcinoid crisis with variable results. Aprotinin failed to block carcinoid symptoms provoked by administration of epinephrine and norepinephrine. The authors found that the use of aprotinin was associated with reduced blood transfusions, but not with differences in mortality. These results suggest that hypotension in patients with carcinoid heart disease should be treated with octreotide, but vasoactive medications can be safely administered for refractory hypotension in the presence of octreotide. |
