Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
Carcinoid Heart Disease
Carcinoid tumors are rare neuroendocrine tumors that secrete vasoactive compounds, including serotonin. The estimated incidence of carcinoid tumors is reported between 1.0 and 8.4 per 100,000. Carcinoid tumors are classified based on their embryologic site of origin: foregut (bronchus, stomach, proximal duodenum), midgut (distal duodenum, jejunum, ileum, appendix, ascending colon), and hindgut (transverse and descending colon, rectum). Midgut tumors arising from the ileum and appendix are the most common. Carcinoid syndrome occurs in 30% to 40% of patients and results from the release of vasoactive compounds into the systemic circulation, leading to intermittent episodes of flushing, diarrhea, bronchospasm, and hypotension. Up to two-thirds of patients with carcinoid syndrome develop carcinoid heart disease, and carcinoid heart disease may also be the presenting problem in up to 20% of patients with carcinoid tumors. ,
Carcinoid Heart Disease
The pathogenesis of carcinoid heart disease remains poorly understood, but vasoactive substances secreted by neuroendocrine cells, including serotonin, prostaglandins, histamine, and bradykinin, are believed to play an important role. In particular, plasma serotonin levels and urine levels of the primary serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) are higher in patients with carcinoid heart disease. , Urine 5-HIAA level of 300 μmol/24 hours or greater is an independent predictor of the development or progression of carcinoid heart disease. Most patients with carcinoid heart disease have liver metastases whose vasoactive compounds reach the heart and systemic circulation via the hepatic vein. However, patients with primary ovarian carcinoid can also develop cardiac involvement in the absence of liver metastases because these compounds can drain directly into the inferior vena cava. ,
Typical cardiac lesions are described as fibrous, plaquelike areas of endocardial thickening that deposit most commonly on the surface of valve leaflets but may also affect the subvalvular apparatus and cardiac chambers. , Right-sided valvular lesions predominate because vasoactive substances are normally inactivated in the lungs. However, left-sided lesions can be seen in up to 15% of patients and are thought to occur in the setting of right-to-left intracardiac shunts, bronchial carcinoids, or high levels of circulating vasoactive substances. , Patients with carcinoid heart disease often present with a murmur or symptoms of right heart failure. The onset of carcinoid heart disease is a marker for increased mortality rates in patients with carcinoid tumors, who have a median survival time of 14 months. ,
You're Reading a Preview
Become a Clinical Tree membership for Full access and enjoy Unlimited articles
If you are a member. Log in here
