Jan. 27, 2015
The recently developed Carcinoid Heart Disease Clinic at Mayo Clinic's campus in Rochester, Minnesota, comprises cardiologists collaborating with experts in oncology, anesthesiology and cardiac surgery to determine optimal medical, surgical and interventional treatment options for affected patients. They also see patients who have had valve replacement surgery for carcinoid heart disease to determine prosthesis function and clinical status.
For the past three decades, Mayo Clinic cardiovascular medical, surgical and anesthesia specialists as well as medical and surgical oncology specialists have provided multidisciplinary care for patients with carcinoid heart disease. During this time, more than 200 patients have had valve replacement surgery for carcinoid heart disease at Mayo Clinic. Mayo Clinic investigators have demonstrated improved survival for patients with carcinoid disease over the years compared with historical controls, in part related to valve replacement surgery.
Carcinoid heart disease affects more than 50 percent of patients with carcinoid tumors, derived from midgut neuroendocrine tissue. These tumors and their metastases produce active substances, including serotonin. Serotonin released from both the primary tumor and metastases causes thickening and dysfunction of the right-sided cardiac valves, with subsequent valve regurgitation.
Patients with severe carcinoid heart disease may be asymptomatic or may present with fatigue, dyspnea, edema or ascites. "In patients with metastatic carcinoid disease, cardiac involvement results in reduced survival compared with those without cardiac involvement," according to Heidi M. Connolly, M.D., a cardiologist at Mayo Clinic's campus in Rochester and director of the Carcinoid Heart Disease Clinic. "Valve replacement surgery improves the survival and symptoms of patients with carcinoid heart disease."
Carcinoid heart disease always involves the tricuspid valve, and pulmonary valve disease affects more than 60 percent of patients. Left-sided valve disease occurs in 10 percent of patients and is thought to occur primarily in those who have an intracardiac shunt, which allows serotonin-rich blood to bypass the filter of the lungs and enter the left heart chambers.
Left-sided valve disease also occurs in patients with very active metastatic disease and high circulating serotonin levels. Cardiac metastases are uncommon, occurring in 5 percent of patients with cardiac involvement. Endocardial right heart plaque deposition is often identified at the time of surgical inspection but rarely causes clinical right ventricular compromise.
Occasionally, identification of carcinoid heart disease is the first clue to recognizing metastatic carcinoid disease. However, in most patients, cardiac involvement occurs years after metastatic carcinoid disease is identified.
An elevation in the brain natriuretic peptide level may raise clinical suspicion of carcinoid heart disease in asymptomatic patients, and some have suggested that this test be used as a screening tool. However, if clinical suspicion is high, echocardiography is the diagnostic test of choice; the echocardiographic appearance of the valves is pathognomonic, and valvular dysfunction can be quantified.
Cardiac magnetic resonance imaging or computerized tomography may provide additional important clinical information in select patients, such as assessment of right heart size and function to determine timing of operation.
There are limited medical treatment options for patients with symptomatic carcinoid heart disease. Diuretics may improve edema and ascites but generally do not relieve symptoms of dyspnea and fatigue. Patients with carcinoid heart disease are candidates for valve replacement if they have symptoms related to their valve disease and progressive right heart enlargement or dysfunction.
"Occasionally, asymptomatic patients with carcinoid heart disease are referred for valve operation to prepare the patient for liver surgery, such as debulking or transplantation," says Dr. Connolly. "Elevated right atrial pressure related to carcinoid heart disease increases the risk of liver surgery, and these patients are best treated with valve replacement before liver resection or transplantation."
Medical management, including therapy with somatostatin analogues such as octreotide, must be optimized before valve surgery or other interventions in an effort to avoid a potentially life-threatening carcinoid crisis in patients with carcinoid syndrome.
Bioprosthetic valves are generally preferred because of the need for future interventions and the risk of anticoagulation in patients with mechanical valve prostheses. Patch enlargement of the pulmonary annulus is sometimes indicated at the time of pulmonary valve replacement. Postoperative treatment with warfarin anticoagulation for six months is recommended.
Valve replacement procedures can be performed at a low risk in patients with controlled metastatic carcinoid disease. In the most recent series from Mayo Clinic (2010 through 2012), cardiac surgical mortality was less than 5 percent.
Occasionally, percutaneous intervention is feasible in patients with carcinoid heard disease, such as device closure of patent foramen ovale and valve-in-valve procedures for patients with bioprosthesis dysfunction.
The multidisciplinary Carcinoid Heart Disease Clinic provides individualized review of patients with carcinoid heart disease to determine the degree of cardiac valve involvement and the best type and timing of intervention.