942-39 Carcinoid Heart Disease: Correlation of High Serotonin Levels with Valvular Abnormalities Detected by Cardiac Catheterization and Echocardiography

BackgroundAlthough seratonin has been postulated as an etiologic agent in the development of carcinoid heart disease, no direct evidence for different ambient serotonin levels in cardiac and noncardiac patients has been reported to date.Methods and ResultsThe present study reviews the experience with 604 patients in the Duke Carcinoid Database. Nineteen patients with proven carcinoid heart disease (by cardiac catheterization and/or echocardiography) were compared with the remaining 585 noncardiac patients in the database with regard to circulating serotonin and its principle metabolite. 5-hydroxyindoleacetic acid (5-HIAA). No significant demographic differences existed between the cardiac and noncardiac groups; however, typical carcinoid syndrome symptoms (i.e. flushing and diarrhea) were almost threefold more common in the cardiac group (p<0.001). The spectrum of heart disease among the 19 patients showed a strong right-sided valvular predominance with tricuspid regurgitation being the most common valvular dysfunction (92% by cardiac catheterization; 100% byechocardiography). No survival differences were found between the cardiac and noncardiac groups. Compared with the noncardiac group, heart disease patients demonstrated strikingly higher (p<0.0001) mean serum serotonin (9750 vs 4350 pmoles/ml), plasma serotonin (1130 vs 426 pmoles/ml), platelet serotonin (6240 vs 2700 pmoles/mg protein), and urine 5-HIAA (219 vs 55.3 mg/24 hr).ConclusionsThese data suggest that serotonin plays a major role in the pathogenesis of the cardiac plaque formation observed in carcinoid patients