Development of severe intrapulmonary shunting in a patient with carcinoid heart disease after closure of a persistent foramen ovale: a case report.

An echocardiographic assessment of the presence of a PFO is recommended in patients with NET as PFO closure minimizes the risk of left-sided carcinoid valve disease. Deterioration of symptomatic status in metastasized NET might also be due to a hepatopulmonary-like physiology with intrapulmonary shunting and arterial desaturation thought to be caused by vasoactive substances secreted by the tumour. This is a rare case describing the development of this syndrome after PFO closure.