Patent Foramen Ovale and its Significance in the Perioperative Period

Patent foramen ovale (PFO), usually a benign and silent lesion (Fig. 1), can cause hypoxemia and embolic phenomena under circumstances when right atrial (RA) pressure exceeds left atrial (LA) pressure or when preferential flow from the inferior vena cava (IVC) toward the PFO persists, as in the prenatal circulation (1–3). These circumstances may occur during the perioperative period as a result of the effect of mechanical ventilation, thromboembolism or air embolism, the altered anatomic relationship between the IVC and interatrial septum, or an increase in intraabdominal pressure. Although not extensively studied, numerous case reports implicate PFO as a causative factor for hypoxemia and systemic thromboembolism in the perioperative period. In the following review, we describe the epidemiology, pathogenesis, modern methods of detection, and general clinical importance of PFO. In particular, we highlight the significance of PFO in the perioperative period.