Abstract
Patients with acute pulmonary embolism (PE) often present with hypoxia; however, their oxygenation typically improves with appropriate respiratory support. Here, we discuss a case of persistent hypoxia in PE attributed to shunting through a patent foramen ovale (PFO). A 77-year-old woman with a history of hypertension and heart failure with preserved ejection fraction presented with acute shortness of breath. A CT angiogram demonstrated bilateral proximal PE involving the lobar pulmonary arteries extending into the segmental branches. Despite BiPAP ( (Bi-level Positive Airway Pressure) support, the patient had worsening hypoxia, with a partial pressure of oxygen (PaO(2)) of 57 mmHg. An echocardiogram demonstrated a pulmonary artery systolic pressure (PASP) of 44 mmHg with right ventricular systolic dysfunction and a right-to-left shunt secondary to a PFO. The patient underwent catheter-directed thrombolysis (CDT), resulting in PFO closure and improvement in PASP to 33 mmHg. Following treatment, she was successfully weaned off supplemental oxygen. Intractable hypoxemia due to a PFO in the setting of acute PE is a rare occurrence, with only a few cases reported. Previously, such cases have been treated with systemic thrombolysis or surgical embolectomy. To our knowledge, this is the first reported case in which CDT successfully resolved the hypoxemia and resulted in PFO closure. In patients with intractable hypoxia in the setting of acute PE, the presence of an interatrial shunt should be considered. CDT can effectively reduce pulmonary pressures by decreasing clot burden, which in turn may reverse the shunt and resolve hypoxia.