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.