Increased prevalence of patent foramen ovale in patients with severe chronic obstructive pulmonary disease

This study was designed to assess the prevalence of patent foramen ovale (PFO) in patients with severe chronic obstructive pulmonary disease (COPD) and the magnitude of any effects of right-to-left interatrial PFO shunting on systemic arterial oxygen desaturation after the Valsalva maneuver. The prevalence of PFO was compared between a group of 20 patients with severe chronic obstructive pulmonary disease (FEV1% <50%; FEV1/FVC <50%) and 20 control subjects (FEV1% >70%; FEV1/FVC >70%) by contrast transesophageal echocardiography during the Valsalva maneuver with simultaneous measurement of systemic arterial oxygen saturation (SaO2) by pulse oximetry. Patients with severe COPD (FEV1 = 27.2% +/- 8.4%; FEV1 /FVC = 44.3% +/- 11.0%) had a significantly higher pulmonary artery systolic pressure (38.3 +/- 7.3 vs 21.0 +/- 2.4 mm Hg; P <.005), higher prevalence of PFO (14/20 = 70% vs 7/20 = 35%; P <.05), and greater systemic arterial desaturation after Valsalva (Sao2 change: -2.6% +/- 1.4% vs -1.1% +/- 0.9%; P <.005) than control subjects. In the severe COPD group, the degree of systemic arterial desaturation after Valsalva in patients with PFO was significantly greater than in patients without PFO (Sao2 change: -3.1% +/- 1.4% vs -1.5% +/- 0. 5%; P <.05). Significant systemic arterial oxygen desaturation was observed after Valsalva in 45% of patients with interatrial PFO shunting and severe COPD. This significantly correlated with the degree of pulmonary hypertension (r = 0.6; P <.05). We conclude (1) that patients with severe COPD have an increased prevalence of PFO and (2) that approximately one half of subjects with severe COPD and PFO demonstrate statistically significant systemic arterial oxygen desaturation after the Valsalva maneuver.