Troponin I, Troponin T, and Creatine Kinase-MB Mass in Patients with the Carcinoid Syndrome with and without Heart Failure

Abstract

Carcinoid heart disease is a well-known complication of longstanding carcinoid syndrome. It is characterized by the presence of “carcinoid plaques” on the mural endocardium (1). The carcinoid plaques are composed of smooth muscle cells, embedded in a stroma of acid mucopolysaccharides and collagen. In the plaques, the elastin fiber content is decreased, and the basal membrane of the endocardium is thickened and sometimes duplicated (2). Carcinoid plaques are found predominantly in the right heart (1), leading to pulmonary and tricuspid valve abnormalities. With echocardiography, tricuspid valve regurgitation is found in 56% of patients with a carcinoid syndrome (3). A correlation of echocardiographic abnormalities with (high) serotonin secretion by the carcinoid tumor has been described (3). Heart failure was a cause of death in 41% of 63 midgut carcinoid patients (4). In patients with a carcinoid syndrome, median survival was significantly reduced by the presence of cardiac involvement (5). Serotonin is a potent vasoconstrictor (6) and can lead to diminished myocardial blood flow (7). Plaque formation itself possibly affects the underlying myocardium. Furthermore, distention of the right heart, resulting from valve abnormalities, could lead to …