INTRODUCTION
Patent foramen ovale (PFO) is a persistent fetal communication that is present in approximately 25% to 30% of the general population (1). The prevalence of PFO in the general population has raised interest in understanding its potential implications, and whether specific features of PFO are associated with a higher risk of adverse clinical outcomes. It is important to note that while most PFOs do not cause any clinical complications, there is a small percentage of cases where PFOs can lead to serious conditions such as paradoxical embolism, embolic stroke of undetermined source (ESUS), and migraine (2,3). Studies have shown a significant association between PFO and both ESUS and migraine (4,5).
Transthoracic echocardiography (TTE) is the initial diagnostic modality for PFO. Color Doppler imaging during TTE can detect a right-to-left color transition in the interatrial septum (IAS) following the Valsalva maneuver, indicating the presence of PFO. Transoesophageal echocardiography is often required to confirm the diagnosis of PFO in adults due to suboptimal transthoracic and subcostal echo windows. In 2D echocardiographic views, the central portion of the atrial septum, which is thin in normal cardiac anatomy, may not be clearly visualized (6). This ”septal drop-out” phenomenon can lead to misinterpretation as PFO, especially in adults (7). Additionally, pulmonary vein flows projecting onto the IAS may be mistakenly perceived as color Doppler flow in the IAS, potentially resulting in misdiagnosis of PFO. Contrast echocardiography, utilizing the passage of microbubbles from the right atrium to the left atrium following peripheral venous injection of agitated saline during the strain phase of the Valsalva maneuver, can aid in establishing the diagnosis of PFO (8). The presence of a shunt is defined as the visualization of more than three contrast bubbles in the left atrium via contrast echocardiography (9). Transesophageal echocardiography (TEE) provides a definitive diagnosis and characterization of PFO.
Understanding the prevalence and potential consequences of PFO is crucial for effective diagnosis, treatment, and management of patients at risk (10). Echocardiographic and clinical characteristics of patients with ESUS and migraine accompanied by PFO are important factors to consider in a comparative analysis. Comparing the echocardiographic and clinical characteristics of patients with embolic stroke of undetermined source and migraine, both accompanied by PFO, can provide valuable insights into the potential mechanisms underlying these conditions and assist in identifying appropriate management strategies.
It has also been shown that the size, length, and width (functional potential) of the PFO, play a critical role in the development of migraine and ischemic stroke. Additionally, presence of atrial septal aneurysm, hypermobile IAS, large right-to-left (RL) shunt, Eustachian valve or a Chiari’s network, and a sharp (≤10°) angle between the inferior vena cava and the PFO flap is associated with a high-risk PFO (11,12).
This study aims to investigate the characteristics of PFO and its potential link to clinical conditions, specifically migraine and ESUS, in a cohort of 720 patients aged between 18 and 60. In this context, we conducted a comprehensive assessment of the PFO characteristics, clinical demographics, and echocardiographic findings in a diverse patient population. Additionally, we compared the characteristics of PFO and the presence of high-risk criteria for paradoxical emboli in patients with migraine and ESUS. This investigation explores the potential differences in PFO morphology, as well as accompanying structural and functional criteria, in patients with migraine and ESUS. It also examines the association between PFO characteristics and the prevalence of microbubble passage through the IAS, a phenomenon linked to paradoxical emboli. The study further assesses the RoPe score, which identifies high-risk clinical features for stroke in ESUS patients, and the High-risk PFO score, used to determine high-risk PFO based on anatomic and functional criteria.