A 74-year-old man with chronic obstructive pulmonary disease (COPD) due to heavy smoking (3 packs/54 years), atrial flutter, and polycythemia (hemoglobin 20.2 g/dL) presented with worsening dyspnea. He had undergone pulmonary valvuloplasty for tetralogy of Fallot at another hospital and was treated with inhaled tiotropium for COPD (Figure A–C). His positional saturation level was lower in sitting positions (SpO2 86%) than in left-side-lying positions (SpO2 93%) on a 3 L/min oxygenation supply. Transthoracic echocardiography showed a remaining atrial septal defect (ASD) mainly with left-to-right shunts. To differentiate the patient’s positional hypoxia, we performed right heart catheterization using a Swan-Ganz pulmonary artery catheter (SGC) via the right jugular vein, which showed no pulmonary hypertension (mean pulmonary artery pressure 13 mmHg). A transcatheter bubble test by injecting microbubbles via a proximal SGC lumen showed few right-to-left shunts during left-side-lying positions but massive right-to-left shunts during sitting positions, confirming platypnea-orthodeoxia syndrome (POS). Furthermore, microbubbles injection into bilateral pulmonary arteries through a distal SGC lumen revealed no intrapulmonary arteriovenous shunts. Thus, it was accurately determined that the patient’s positional hypoxia was mainly caused by POS (Figure D,E). Transesophageal echocardiography in the left-side-lying position showed a 13.3-mm secundum ASD, where transcatheter ASD closure using an 18-mm Occlutech septal occluder (Figulla Flex II; Occlutech International AB, Helsingborg, Sweden) was performed after atrial flutter catheter ablation (Figure F,G). Thereafter, the patient’s dyspnea during postural changes improved markedly.
Figure.
(A) Chest radiography showing a barrel chest. Arrowheads indicate barrel chest. (B) Computed tomography showing airway wall thickening (arrows) and pulmonary emphysema (arrowheads). (C) Spirometry showing obstructive respiratory disorders. FEV1, forced expiratory volume in 1 s; VC, vital capacity. (D) Transthoracic echocardiography showing an atrial septal defect (ASD) with a minor right-to-left shunt. (E) Transcatheter bubble test. (F) Transesophageal echocardiography. (G) Transcatheter ASD closure with the Figulla Flex II (Occlutech International AB).
POS diagnosis is often difficult in older patients with COPD because of low resting oxygenation and the frequent association with intrapulmonary arteriovenous shunts. Moreover, even after POS diagnosis, transcatheter ASD closure should carefully be performed after evaluating the severity of the pulmonary hypertension. Therefore, transcatheter hemodynamic evaluation and a concomitant bubble test via proximal/distal SGC lumens, may “kill 2 birds with one stone”, helping diagnose and guiding appropriate managements in POS patients with complex histories.
Disclosures
None.