Prevalence of Patent Foramen Ovale and Its Contribution to Hypoxemia in Patients with Obstructive Sleep Apnea

The objectives of this study were (1) to assess the prevalence of patent foramen ovale (PFO) by means of contrast transesophageal echocardiography (TEE) in patients with obstructive sleep apnea, and (2) to determine the potential contribution of right to left interatrial shunting to systemic oxygen desaturation following the performance of Valsalva maneuver. Performance of contrast TEE during Valsalva maneuver with simultaneous measurement of systemic arterial oxygen saturation (SaO2) by means of pulse oximetry in patients with obstructive sleep apnea and a control group. Government teaching hospital, university hospital affiliate. Study group comprised 48 patients with documented obstructive sleep apnea and 24 control subjects. Sleep studies, contrast TEE, Valsalva maneuver, pulse oximetry. Thirty-three of 48 patients with obstructive sleep apnea compared with 4 of 24 control patients had a detectable PFO (69% vs 17%; p4 SD of recorded SaO2 values after Valsalva maneuver in patients without PFO) was found in one third of patients with sleep apnea and PFO. We conclude that there is an increased prevalence of PFO in patients with obstructive sleep apnea that could contribute to significant hypoxemia after a Valsalva maneuver in approximately one third of these patients.