Persistent hypoxemia and platypnea-orthodeoxia after left single-lung transplantation: a case report

Abstract

IntroductionPlatypnea-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.Case presentationOur 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.ConclusionsOur 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.

Patent Foramen Ovale–Related Hypoxemia After Bilateral Lung Transplant

“… 1 , 3 Rarely, post-LTx hypoxemia has been reported because of unrecognized or unrepaired PFO that results in significant Rt-to-Lt shunting. 4 , 5 …”

“… 6 It is usually small and without any hemodynamic consequences, but if a shunt occurs, it usually goes from left to right because of a decrease in pulmonary artery pressure and an improvement in right ventricular compliance following LTx; however, a few cases of hypoxemia after unilateral LTx, resulting from persistent Rt-to-Lt shunting across a PFO, have been reported. 4 , 5 The etiopathogenesis of persistent Rt-to-Lt shunting across the PFO after LTx is not well understood. It has been postulated that after unilateral LTx, anatomic alterations in the position of the interatrial septum resulting from the mediastinal shift may open the physiologically closed PFO, and the presence of a large eustachian valve may direct blood from the inferior vena cava preferentially to the left atrium across the PFO.…”

“…It has been postulated that after unilateral LTx, anatomic alterations in the position of the interatrial septum resulting from the mediastinal shift may open the physiologically closed PFO, and the presence of a large eustachian valve may direct blood from the inferior vena cava preferentially to the left atrium across the PFO. 4 , 5 , 7 , 8 All reported cases of hypoxemia following LTx have followed unilateral LTx.…”

Platypnea-orthodeoxia syndrome after open prostatectomy and cystolithotomy: Coincidence or unknown pathophysiology?

“…Moreover, the fact that the episodes were more frequent, severe, and sustained after surgery led to the hypothesis that surgery could have exacerbated this phenomenon in some way, but the pathophysiology was not clear. In surgical patients, cases of POS after pneumectomy 11 or single-lung transplantation 12 have been described, probably because there are a number of anatomical thoracic changes after these types of surgery that could favor right-to-left shunt in the presence of PFO. Previous cases of POS after upper abdominal surgery 8–10,13 or nonsurgical conditions, in which the right diaphragm was elevated, 14,15 have been reported, and this anatomical change was the common finding that could have favored the right-to-left atrial shunt in these patients.…”