Title : The incidence and characteristics of patent foramen ovale in patients with embolic stroke of undetermined source
Abstract:
Background and Aims: Patent Foramen Ovale (PFO) has been associated with Embolic Stroke of Undetermined Source (ESUS) . It remains uncertain whether PFO is the direct etiology or an incidental finding. The aim of our study was to analyze the incidence and characteristics of PFO in patients with ESUS.
Methods: A prospective Tunisian study was conducted from 2017 to 2020. ESUS was defined according to the criteria proposed by the Cryptogenic Stroke /ESUS International Working Group. According to these criteria, all patients underwent a transthoracic echocardiography (TTE) . To detect a PFO, we performed a microbubble test with a Valsalva maneuver. Once detected by the TTE , the characteristics of PFO ( diameter, coexistence of an atrial septal aneurysm or hypermobile septum) were analyzed by a Transesophageal echocardiography (TEE) .
Results: A total of 330 patients were enrolled. Among them, 66 (20%) patients had ESUS . Patients in the ESUS group had a mean age of 57.09 ± 11 years with a clear male predominance (68.2%), a history of hypertension (53%) and smoking (48.5%). The mean NIHSS score was 6.82 ± 3.073 on admission. Most patients in the ESUS group (79.7%) had favorable outcomes . Most patients (68,2% ) had cortical infarcts on brain imaging. The main potential embolic sources were atrial cardiopathy (71.2%) and non-stenotic carotid plaques (41.7%) . Patent Foramen Ovale (PFO ) was objectived in 24.2% patients. Large PFO ( diameter > 2 mm) and Atrial septal aneurysms (ASA) were fund in 4 and 4 patients respectively. Three patients had both large PFO and ASA.
Discussion: In our study, patients with ESUS were relatively young and had fewer cardiovascular risk factors. Etiologically, 16 (24.2%) patients were identified to have a PFO . PFO was large in 4 patients and with atrial septal aneurysms or hypermobile septa in 4 patients. Similar to our results , a recent meta-analysis found a prevalence of 24% based on autopsy series. Added to that , in the NAVIGATE-ESUS trial , PFO was objectified in 27% of patients [1,2].The precise mechanism of the causation of ischemic stroke by the PFO could be explained by the hypothesis according to which the PFO allows a venous thrombus migrating to the right atrium to cross the septum and embolize a cerebral artery as well as other systemic arteries [3,4].
Conclusion: The presence of PFO may be a likely embolic source or a risk factor in patients with ESUS. More prospective studies are necessary to study the association between PFO and ESUS.
