Introduction: The carcinoid heart disease is an uncommon valvular heart disease that may occur in carcinoid syndrome.Valvulopathy is reported in 50% to 70% of patients of carcinoid syndrome, due to the release of serotonin secreted by metastatic cells in the liver, reaching directly right side of heart. The left side is preserved because of inactivation of serotonin by lung parenchyma. Hypoxemia is an unusual presentation of the carcinoid heart disease.
Case report: We present a case of 65 years-old woman admitted for repetitive falls. She was known to have a carcinoid tumour of midgut origin with hepatic, pulmonary and bone metastasis. She presented with hypoxemia (85%) and signs of right-sided heart failure without severe dyspnoea (NYHA stage 1). Biologically, NT proBNP was 1341 ng/l (usual value for the age: <900), blood gas analysis showed a shunt effect (PO2 53 mmHg, PCO2 34 mmHg). The hypoxemia did not correct with oxygen and the use of diuretics. An angioscan ruled out a pulmonary embolism. A transthoracic echocardiography showed an ejection fraction of left ventricle at 53%, a carcinoid cardiopathy with a retracted and thickened tricuspid valve with diastasis of the cusps, and a tricuspid insufficiency. The contrast echocardiography showed a patent foramen ovale (PFO) with a continuous right to left shunting, explaining the oxygen desaturation without left-sided heart failure.
Discussion and conclusion: Once the opening of the foramen ovale occurs, the left side of the heart is exposed to serotonin effects, leading to a risk of left, and then congestive heart failure which, at least, may alter the prognosis of the disease. The discovery of a PFO is an important marker of carcinoid heart disease progression and should be systematically assessed with routine contrast transthoracic echocardiography in patients with carcinoid syndrome.