Current concepts in diagnosis and perioperative management of carcinoid heart disease

Carcinoid tumors are neuroendocrine tumors with a very unpredictable clinical behavior. In the setting of hepatic metastases, the tumor's release of bioactive substances into the systemic circulation results in carcinoid syndrome: a constellation of symptoms among which cutaneous flushing, gastrointestinal hypermotility, and cardiac involvement are the most prominent. Cardiac manifestations, also known as carcinoid heart disease, are secondary to a severe fibrotic reaction which frequently involves the right-sided valves and may extend towards the subvalvular apparatus leading to valve thickening and retraction. Left-sided involvement is rare and mostly observed in the presence of an interatrial shunt, endobronchial tumor localization, and high tumor activity. Echocardiographic techniques often reveal noncoaptation of the valves, which are fixed in a semiopen position. In patients with advanced lesions and severe valvular dysfunction, surgery is currently the only definitive treatment to potentially improve quality of life and provide survival benefit. Although cardiac surgery has been traditionally reserved for those patients with symptomatic right ventricular failure, a significant trend towards improved surgical outcomes has triggered a more liberal referral for valve replacement. Carcinoid heart disease poses two distinct challenges for the anesthesiologist: carcinoid crisis and low cardiac output syndrome secondary to right ventricular failure. Carcinoid crisis, characterized by flushing, hypotension, and bronchospasm, may be precipitated by catecholamines and histamine releasing drugs used routinely in patients undergoing valve surgery. Although a broader utilization of octreotide have significantly simplified the anesthetic and perioperative management of these patients, a very balanced anesthetic technique is required to identify and manage low cardiac output syndrome.