Percutaneous closure of a secundum ASD with a 37-mm Cardioform device normalized oxygen saturation (≥95% on room air) and resolved dyspnea within 24 hours.
Case Report (n=1)
A hemodynamically silent ASD can be unmasked by a viral illness causing transient right-to-left shunting and severe hypoxemia, which resolves rapidly after percutaneous device closure.
Abstract Introduction Right-to-left shunting across an atrial septal defect (ASD) can cause severe hypoxemia that clinically resembles pulmonary hypertension (PH). Distinguishing intracardiac shunting from pulmonary vascular disease is critical given the difference in management. We report a patient with acute hypoxemic respiratory failure whose presentation suggested right ventricular (RV) failure, requiring awake intubation. Comprehensive evaluation revealed a large intracardiac shunt with rapid resolution after transcatheter closure. Case Report A 54-year-old female with Takotsubo cardiomyopathy and no prior lung disease presented with worsening oxygen requirements after a rhinovirus infection. On arrival, she was in acute hypoxemic respiratory failure on high-flow nasal cannula (40 L/min, FiO2 100%) with arterial blood gas pH 7.46/pCO2 17/pO2 44 mmHg. Physical exam showed platypnea and orthodeoxia without JVD. CT angiography excluded pulmonary embolism or parenchymal lung disease. Inhaled nitric oxide (iNO) was started. Initial transthoracic echocardiogram (TTE) showed normal LV ejection fraction (60%), mildly reduced RV function, small anterior pericardial effusion, and low RV systolic pressure (∼15 mmHg). She had cirrhotic morphology on ultrasound. Infectious and connective-tissue workups were negative. Her oxygenation improved and she was weaned off iNO, later extubated to noninvasive support. A repeat limited TTE with bubble study was positive. Transesophageal echocardiography revealed an aneurysmal interatrial septum with a small secundum ASD versus large patent foramen ovale and grade-4 right-to-left shunting. Right-heart catheterization showed no PH (RA 8 mmHg; PA 24/13 mmHg; mean 17; PCWP 11). A 1.5 × 1.0 cm secundum ASD was closed percutaneously with a 37-mm Cardioform device. Within 24 hours, oxygen saturation normalized (≥95% on room air), and dyspnea resolved. She was discharged on dual antiplatelet therapy with outpatient follow-up. Discussion This case illustrates a delayed presentation of a hemodynamically silent ASD unmasked by viral illness. The transient viral-induced rise in pulmonary vascular resistance (PVR) reversed the normal atrial pressure gradient, producing severe R-L shunting and hypoxemia despite normal pulmonary pressures. iNO improved oxygenation by lowering PVR and right-atrial pressure, temporarily restoring left-to-right shunting until closure. Such cases can mimic pulmonary vascular disease or hepatopulmonary syndrome, where PH-directed therapy might delay correct diagnosis. Early recognition of shunting via bubble study was pivotal, guiding curative device closure and avoiding unnecessary PH treatment. This abstract is funded by: NA
Bcharah et al. (Fri,) conducted a case report in Secundum atrial septal defect with severe hypoxemia (n=1). Percutaneous closure with a 37-mm Cardioform device was evaluated on Resolution of hypoxemia and dyspnea. Percutaneous closure of a secundum ASD with a 37-mm Cardioform device normalized oxygen saturation (≥95% on room air) and resolved dyspnea within 24 hours.