Prevalence and clinical significance of a patent foramen ovate in

Abstract

Background: A patent foramen ovate (PFO) is not widely recognized as a factor contributing to hypoxemia in patients with chronic obstructive pulmonary disease (CCPD). We therefore sought to clarify the prevalence and clinical significance of a PFO in patients with COPD, and to analyze the factors related to its occurrence. Methods: This study included 52 consecutive stable patients with COPD and 50 healthy controls. The demographic and clinical features of the study group were noted. To test for a PFO, standard and contrast transthoracic echocardiographic examinations were performed while resting and during the Valsalva maneuver (VM). Patients performed 6-min walking tests (6 MWT), and the distances traveled were measured.

Results: During VM, we detected a PFO in 23 COPD patients and 10 healthy controls (P < 0.01). A PFO was detected while resting in 11 COPD patients, but in none of the controls (P = 0.001). Comparison of multiple parameters between COPD patients with and without a PFO during VM did not reveal any clinically significant differences. When we compared COPD patients with and without a PFO during resting, however, we found that the former had longer durations of disease, lower PaO2 and SaO(2), higher dyspnea scores, shorter distances walked during 6 MWT and higher desaturation rates (P < 0.05). Logistic regression analysis showed that longer duration of disease, lower SaO(2) and higher systolic pulmonary artery pressure were independent predictors of the occurrence of a PFO in resting COPD patients.

Conclusions: The prevalence of a PFO is higher in patients with COPD than in healthy individuals. The presence of a PFO while resting may contribute significantly to the deterioration of arterial oxygenation and performance status. These findings indicate that a PFO may be a principle cause of hypoxemia in patients with COPD. (c) 2005 Elsevier Ltd. All rights reserved.