Abstract 17520: Dynamic Intrapulmonary Shunting in the Setting of Amphetamine Use

Abstract

Description of Case: A 35-year-old female non-smoker with ADHD on amphetamine for the past 3 months and family history of hereditary hemorrhagic telangiectasia (HHT) presented with significant exertional dyspnea for 1 week. She was hypoxic to 82% while walking, with normal oxygen saturation at rest. Transthoracic echocardiogram with agitated saline revealed extracardiac right-to-left shunting with exercise and Valsalva. This was confirmed by dobutamine stress echocardiogram with agitated saline (Figure 1A). Transesophageal echocardiogram with agitated saline (Figure 1B) revealed no shunt through the foramen ovale, but it demonstrated bubbles entering from the left upper pulmonary vein, suggestive of an extracardiac shunt from a pulmonary arteriovenous malformation (AVM). Right heart catheterization and pulmonary angiogram revealed normal pressures, and no pulmonary abnormalities with normal pulmonary venous return. Supine right heart catheterization with exercise revealed normal pressures, although the initial pulmonary artery (PA) saturation was 28%; repeat PA saturation one minute later was 48%. Arterial saturation was 95%. Pulmonary function testing, ventilation perfusion scan, high-resolution CT chest, and coronary CT angiogram were unremarkable. The patient was instructed to avoid all stimulants, and to take a non-hormonal contraceptive. At her 3-month follow-up, she reported significant improvement in her symptoms. She underwent a 6-minute walk test, and her lowest oxygen saturation was 88%. Discussion: This patient presented with exertional hypoxia, normal saturations at rest, evidence of an extracardiac shunt only with exertion and absence of clear sources of the shunt on imaging. With her family history of HHT, this is suggestive of a small pulmonary AVM that opened by elevated PA pressures, likely triggered by amphetamine use, and its discontinuation led to symptom resolution.