Is cardiopulmonary bypass really the cause of postoperative atrial fibrillation?

Medical management of secretory syndromes related to gastroenteropancreatic neuroendocrine tumours

Although recent epidemiological evidence indicates that the prevalence of non-functioning gastroenteropancreatic (GEP) neuroendocrine tumours (NETs) is rising, a significant number of GEP-NETs still present with symptoms related to the secretion of biologically active substances leading to the development of distinct clinical syndromes. In the past, these syndromes were associated with substantial morbidity and mortality due to the lack of specific therapies; however, since the introduction of long-acting somatostatin analogues and medications such as proton pump inhibitors, their control has been greatly improved. As a result, nowadays, the main cause of morbidity and mortality in GEP-NETs is mostly directly related to tumour growth and the extent of metastatic disease. However, in some patients with functioning tumours and extensive disease, control of the secretory syndrome still remains problematic, necessitating the employment of several cytoreductive techniques, which may not always be sufficient. Recently, new agents directed against tumour growth, or exerting increased binding activity to receptors expressed in these tumours, or interfering with the synthetic pathway of some of the compounds secreted by these tumours, have been developed. Since there are no specific guidelines addressing the totality of the management of the secretory syndromes related to GEP-NETs, this review aims at critically analysing the medical management of previously recognised secretory syndromes; it also addresses areas of uncertainty, assesses the newer therapeutic developments and also addresses recently described but poorly characterised secretory syndromes related to GEP-NETs.

Carcinoid valve disease

OPINION STATEMENT

Carcinoid is a rare neuroendocrine tumor that typically originates in the gastrointestinal tract and can result in a constellation of symptoms, mediated by vasoactive substances, referred to as carcinoid syndrome. Carcinoid valve and heart disease is characterized by the plaque-like, endocardial fibrous tissue deposits, primarily affecting the right heart endocardium and valves, which result as a consequence of the disease process. Potential mechanisms for the carcinoid valve disease include the complex role of excess serotonin and its interaction with serotonin receptors and transporters. Carcinoid valve and heart disease is a frequent occurrence in patients with carcinoid syndrome and is accountable for substantial morbidity and mortality. Cardiac surgery remains the most effective treatment option for carcinoid valve disease and a multidisciplinary approach at an experienced center is recommended for patients with metastatic carcinoid and carcinoid heart disease.

Right- and left-sided carcinoid heart disease without intracardiac shunting

We present a case of a 54-year-old man with carcinoid heart disease and mitral valve involvement. He had hepatic carcinoid with an extremely elevated urinary excretion of 5-hydroxyindole acetic acid and was referred to our division for shortness of breath and leg edema. Transthoracic echocardiography showed the thickened and retracted tricuspid valve leaflets and severe tricuspid regurgitation. Moderate mitral regurgitation was observed, with the involvement of mitral valve leaflets. A patent foramen ovale was not detected on transesophageal echocardiography. The extremely high concentration of circulating serotonin and/or other vasoactive substances may have contributed to left- as well as right-sided carcinoid heart disease.

Carcinoid tumor and carcinoid syndrome

PURPOSE OF REVIEW

Carcinoid tumors secrete many different types of substances (e.g. serotonin, bradykinin) that may produce potentially fatal intraoperative reactions such as hypotension and bronchoconstriction. The most effective treatment for the deleterious cardiovascular and pulmonary effects of serotonin and bradykinin is octreotide, a somatostatin analogue. Carcinoid heart disease, which develops in the majority of patients with carcinoid syndrome, presents the anesthesiologist with more diagnostic and therapeutic dilemmas.

RECENT FINDINGS

The incidence of carcinoid tumors is much greater than previously recognized. New diagnostic techniques permit identification and localization of carcinoid tumors with greater accuracy. Short term and long term therapy with octreotide significantly improves survival and reduces the severity of 'carcinoid crises'. Echocardiographic studies have demonstrated a very high incidence of carcinoid heart disease (tricuspid and pulmonary insufficiency) in patients with carcinoid syndrome. Cardiac valve surgery is, consequently, becoming much more common in patients with carcinoid syndrome.

SUMMARY

More patients with carcinoid tumors and carcinoid syndrome are requiring anesthesia and surgery. Specific therapy with somatostatin analogues (octreotide) has replaced older less specific drugs (e.g. antihistamines) for the treatment of adverse effects caused by products of carcinoid tumors.