title: Persistent hypoxemia and platypnea-orthodeoxia after left single-lung transplantation: a case report.
abstract: BACKGROUND
  Platypnea-orthodeoxia is a relatively uncommon but striking clinical syndrome characterized by dyspnea and deoxygenation accompanying a change to sitting or standing from a recumbent position. Hypoxemia early after lung transplant can have multiple etiologies. We report a rare case of persistent hypoxemia and platypnea-orthodeoxia after left single-lung transplantation, as a result of right-to-left interatrial shunt through a patent foramen ovale, with subsequent resolution of hypoxemia after percutaneous closure of the patent foramen ovale.
  
  
  METHODS
  Our 66-year-old Caucasian male patient exhibited a persistent patent foramen ovale. Persistent patent foramen ovale produces an intermittent intra-atrial right-to-left shunt and occurs in approximately 25 % of the general population. Although the majority of people with patent foramen ovale are asymptomatic, it is believed to act as a pathway for chemicals or thrombi that can result in a variety of clinical manifestations, including stroke, migraine headache, decompression sickness, high-altitude pulmonary edema, and platypnea-orthodeoxia syndrome. Percutaneous closure of the patent foramen ovale has been shown to be effective in the case of right-to-left shunting with normal pulmonary arterial pressure, but the indication remains controversial in other situations where pulmonary pressures are not normal. The most common causes of hypoxemia immediately after lung transplant include: graft dysfunction, reperfusion injury, acute thromboembolic disease, and acute rejection. We report a case of reopening of a patent foramen ovale after left single-lung transplantation with normal pulmonary pressure.
  
  
  CONCLUSIONS
  Our case demonstrates that an open patent foramen ovale leading to massive right-to-left shunting is a possible complication after lung transplant, with significant morbidity, and that it can be treated successfully using a percutaneously placed occlusion device. Through this case report, we aim to improve pre-transplant procedures by demonstrating that a bubble contrast transesophageal echocardiogram can be performed pre-operatively to detect a patent foramen ovale.
authors.affiliation: Department of Biochemistry, University of Houston, 4800 Calhoun Rd., Houston, TX, 77004, USA. hamsalim@gmail.com.
authors.forename: Hamza
authors.initials: H
authors.lastname: Salim
authors.affiliation: Memorial Hermann System/ Fellowship at Baylor College of Medicine, Memorial Hermann Northwest Hospital, 1635 North Loop Houston, TX 77008. Baylor College of Medicine, 1 Baylor Plaza, Houston, TX, 77030, USA. melengio@gmail.com.
authors.forename: Jose
authors.initials: J
authors.lastname: Melendez
authors.affiliation: Lexington, KY (Private Practice). Formerly at Methodist Hospital's JC Walter Jr Lung Transplant Center/Fellow at Baylor College of Medicine, Houston Methodist Hospital 6565 Fannin Street, Houston, TX 77030. 740 S Limestone A301, Lexington, KY, 40536, USA. sharish@bcm.edu.
authors.forename: Harish
authors.initials: H
authors.lastname: Seethamraju
mesh_terms: D000015:Abnormalities, Multiple; D000368:Aged; D004417:Dyspnea / Q000209:etiology*; D017548:Echocardiography, Transesophageal; D054092:Foramen Ovale, Patent / Q000150:complications* / Q000175:diagnosis; D006801:Humans; D000860:Hypoxia / Q000209:etiology*; D016040:Lung Transplantation; D008297:Male; D011183:Postoperative Complications / Q000175:diagnosis*; D011187:Posture / Q000502:physiology*; D013577:Syndrome