Platypnea-orthodeoxia syndrome associated with bioprosthetic tricuspid valve stenosis and reverse Lutembacher syndrome.

A 43-year-old woman presented with shortness of breath. She developed dyspnea on exertion 6 months prior to presentation, with resting shortness of breath for 2 months. Dyspnea was worse in the upright position. She recently noted that her lips were turning blue in color. Her past medical history was significant for intravenous drug abuse, hepatitis C, and tricuspid valve (TV) endocarditis 3 years prior. She underwent TV replacement with a bioprosthetic valve that was complicated by chest wall necrotizing fasciitis and septic embolism with brain abscess requiring craniotomy. She reported tobacco use, medication noncompliance, and continued intravenous drug abuse. Medications included albuterol/ipratropium, pantoprazole, and furosemide. She had been started on continuous home oxygen. She presented to another institution and was found to have a patent foramen ovale (PFO). Coronary angiography showed no significant coronary artery disease, and chest computed tomography angiography demonstrated normal lung parenchyma and no pulmonary embolus. She was referred to our institution for percutaneous PFO closure. Admission vital signs and basic labs are shown in Table 1. Pulse oximetry on 5L continuous oxygen by nasal cannula was 75% to 78%. When upright, her oxygen saturation decreased to 65% and she became more tachypneic, findings consistent with the platypnea-orthodeoxia syndrome. Physical examination showed perioral cyanosis, no jugular venous distention, clear lungs, and no cardiac murmurs. Arterial blood gas on 40% FiO2 demonstrated a chronic respiratory alkalosis with a compensatory metabolic acidosis. The electrocardiogram showed sinus tachycardia. An echocardiogram demonstrated a 9 mm Hg gradient across the TV, which was otherwise not well seen (Movie 1, Figure 1A). Right heart catheterization confirmed a 9 mm Hg gradient, consistent with severe TV stenosis (Figure 1B), and an oximetry run demonstrated arterial desaturation without left-to-right shunt (Table 2). Pulmonary angiography did not show arteriovenous malformations (Movie 2). Inferior vena cava venography demonstrated simultaneous opacification of the right ventricle and left atrium, consistent with a large right-to-left interatrial shunt (Movie 3). Transesophageal echocardiography showed significant thickening of the bioprosthetic TV leaflets with severely restricted leaflet motion and a large mass of low echo density (Movies 4A and 4B). 3D imaging showed a severe reduction in valve orifice area with a slit-like appearance (Movie 5). The transesophageal echocardiography also confirmed a significant right-to-left interatrial shunt through a large PFO (Figure 2, Movie 6). Cardiac magnetic resonance imaging confirmed the shunt (Figure 3, Movie 7), showed the TV mass (Figure 4, Movie 8) and demonstrated a Qp/Qs of 0.5. The patient was started on anticoagulation and high-flow oxygen but remained markedly hypoxemic and symptomatic due to the shunt. Because of the large PFO and possibility of embolism, fibrinolytics were not considered. Early valve failure may have been due to noncompliance with warfarin treatment after the initial operation or the inability to treat with warfarin due to perioperative complications at that time. A hypercoagulability work-up was negative. There was no