Carcinoid heart disease: medical and surgical considerations.

Carcinoid tumors are rare, arising in 1.2-2.1 per 100,000 people in the general population per year.1 In 20%-30% of patients, the initial presentation occurs as a result of peptide production, ie, carcinoid syndrome. The malignant carcinoid syndrome consists of flushing, gastrointestinal hypermotility (secretory diarrhea), bronchospasm, and carcinoid heart disease. The syndrome is caused by the release of the vasoactive substances 5-hydroxytryptamine (serotonin), 5-hydroxytryptophan, histamine, bradykinins, tachykinins, and prostaglandins. The diagnosis of carcinoid syndrome is usually suspected by clinical features and confirmed by elevation of the byproduct of serotonin metabolism, 5hydroxy indole acetic acid (5HIAA). The urinary 5-HIAA (24hour collection) is a specific and reproducible test that provides a reliable biological marker for the assessment of tumor activity and the response to intervention.2 Measurement of circulating plasma chromogranin A, a protein produced by neuroendocrine cells, has also become a useful marker for carcinoid tumor diagnosis and follow-up.3,4