PURPOSE: 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 after lung transplant can have multiple etiologies. We report a rare case of persistent hypoxia and platypnea-orthodeoxia after lung transplantation as a result of right-to-left interatrial shunt (RLIAS) through a persistent formane ovale (PFO).
METHODS: A 66 year old male underwent left single-lung-transplant (SLT) for idiopathic pulmonary fibrosis. Patient was extubated on post-transplant day one. On day two, he complained of dyspnea with documented hypoxemia while sitting and during physical activity. This was associated with increased oxygen requirement. Extensive evaluation including bronchoscopy with biopsy and CT angiogram were negative. V/Q scan showed no evidence of pulmonary embolism but a significant right to left shunt. Echocardiogram with agitated saline confirmed a PFO with right to left shunt with normal pulmonary pressures. The patient underwent percutaneous closure of the PFO with AMPLATZER® atrial septal occluder. Post closure, he had immediate significant improvement in oxygen saturation in the catheterization lab. Patient was eventually discharged home on room air.
RESULTS: Platypnea-orthodeoxia from RLIAS with normal right heart pressures is a rare complication after lung transplant, with only 1 prior case reported in English literature. Similar presentation has also been seen after right pneumonectomy. Although the exact pathophysiology is not known, it has been postulated that an altered anatomic relationship occurs between the inferior vena cava (IVC), superior vena cava, and the atrial septum after right pneumonectomy and in our case, left SLT. This can cause preferential flow and streaming of blood into left atrium from IVC through a PFO, even in the absence of a pressure gradient. Additionally, the interatrial septum can be pulled downward due to shift in mediastinum resulting in a new opening of foramen ovale and RLIAS. Percutaneous closure is the preferred treatment.
CONCLUSIONS: RLIAS is a rare complication after left SLT resulting in significant morbidity. This complication should be considered in post-transplant patient with unexplained dyspnea and hypoxemia. Percutaneous closure is the preferred treatment.
CLINICAL IMPLICATIONS: Pre-transplant workup should include interatrial shunt evaluation.
DISCLOSURE: The following authors have nothing to disclose: Jose Melendez, Amarbir Mattewal, Harish Seethamraju
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