Patent foramen ovale (PFO), stroke and pregnancy

Abstract

Patent foramen ovale (PFO)-related stroke is increasingly recognized as an important etiology of ischemic embolic stroke—accounting for up to 50% of strokes previously considered ‘cryptogenic’ or with an unknown mechanism. As a ‘back door to the brain,’ PFO can allow venous clots to enter arterial circulation via interatrial right-to-left shunting, potentially resulting in ischemic stroke. We observe that clinically, PFO-related stroke affects women of childbearing age, and that pregnancy—owing to major changes in hemocoagulative, hormonal, and cardiovascular parameters—can enhance stroke risks. However, no systematic study has been performed and little is known regarding complications, pregnancy outcomes and treatment for PFO-related stroke during pregnancy. To identify and characterize the complications and clinical outcomes related to PFOs during pregnancy, we performed a literature review and analysis from all reported cases of pregnancy with PFO-related complications in the medical literature from 1970 to 2015. We find that during pregnancy and post-partum, PFO is associated with complications affecting multiple organs, including the brain, heart and lung. The three principal complications reported are stroke, pulmonary emboli and myocardial infarction. In contrast to other pregnancy-related stroke etiologies, which peak during later pregnancy and postpartum, PFO-related stroke peaks during early pregnancy (first and second trimester—60%), and most patients had good neurological outcome (77%). In patients with PFO with recurrent stroke during pregnancy, additional key factors include high-risk PFO morphology (atrial septal aneurysm), larger right-to-left shunt, multiple gestation and concurrent hypercoagulability. Compared to strokes of other etiologies during pregnancy, most PFO stroke patients experienced uneventful delivery (93%) of healthy babies with a good clinical outcome. We conclude with recommended clinical treatment strategies for pregnant patients with PFO suggested by the data from these cases, and the clinical experience of our Cardio-Neurology Clinic.