Progressive right heart failure after transcatheter closure of patent foramen ovale in a patient with platypnea-orthodeoxia syndrome.

Platypnea-orthodeoxia syndrome (POS) is associated with right-to-left shunting through a patent foramen ovale (PFO). There have been many reports of transcatheter PFO closure in recent years. We report a case of an 89-year-old woman with POS who developed the condition after surgery for a Stanford type A acute aortic dissection. Transthoracic echocardiography revealed severe tricuspid regurgitation. Subsequently, transesophageal echocardiography showed a right-to-left shunt via PFO. Right heart catheterization revealed no findings of elevated cardiac filling pressures or pulmonary hypertension. She underwent transcatheter PFO closure, which led to postoperative improvement in her hypoxemia. However, right heart dilatation and right ventricular dysfunction developed three months following the closure. In our case, pre-existing severe atrial functional tricuspid regurgitation likely intensified to the right-to-left shunt via PFO. The cardiac morphological deformities associated with severe kyphosis and/or previous open-heart surgery also adversely affected the pathophysiology of POS. Following PFO closure, the loss of the right-to-left shunt resulted in right heart volume overload in the presence of severe tricuspid regurgitation, leading to progressive right heart failure. This case highlights the importance of careful evaluation before PFO closure in patients with severe tricuspid regurgitation, even in the absence of preoperative pulmonary hypertension. Learning objective: Percutaneous patent foramen ovale (PFO) closure is a treatment option for resolving platypnea-orthodeoxia syndrome (POS). In patients with PFO, the coexistence of severe tricuspid regurgitation has been identified as a factor associated with the development of POS and with the progression of right heart failure following interventional closure. Even in the absence of preoperative pulmonary hypertension, the potential for worsening right heart failure after PFO closure should be considered.