Carcinoid heart disease: a clinical pathologic, and therapeutic update.

The carcinoid syndrome is a rare clinical entity, the unique manifestations of which continue to excite the interest of physicians. Despite a common origin from neural crest tissue, the tumors are partially differentiated, as evidence by the different secretory products of foregut, midgut, and hindgut carcinoids. They also differ in their ability to metastasize, thus presenting an even more varied clinical picture. The prognosis of patients with carcinoid syndrome varies with the origin of the tumor and extent of metastases. The management of patients with carcinoid syndrome is difficult. Despite an understanding of the neurohormones that carcinoid tumors secrete, their various antagonists and inhibitors have been only partially successful in providing symptomatic relief. Carcinoid heart disease represents the most intriguing aspect of this syndrome. Although valvular dysfunction most often coexists with flushing and diarrhea, the findings of tricuspid regurgitation or stenosis occasionally provide the first clue to the presence of the disease. Despite intensive research, the definite etiology of these valvular lesions has not been established. A small group of patients has been managed by valve replacement. While surgical treatment has been successful in improving hemodynamics in most of these patients, it is expected to prolong life only in those without extensive liver metastases. In patients with extensive metastatic disease, one must carefully consider whether the risks and trauma of cardiac surgery for palliation are justified.