Patent Foramen Ovale: Clinical Implications and Ophthalmological Manifestations

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Patent foramen ovale (PFO) is a prevalent congenital cardiac anomaly marked by a persistent opening between the atrial septum, allowing communication between the left and right atria. Typically, changes in blood pressure after birth lead to the closure of the foramen ovale in about 75% of newborns, resulting in an estimated prevalence of 25–30% in the general population. This defect presents a potential pathway for paradoxical embolism, enabling venous thrombi or other embolic material to bypass pulmonary circulation and enter systemic circulation, leading to significant clinical consequences.

Understanding Patent Foramen Ovale (PFO)

Patent Foramen Ovale (PFO) is a common condition that affects the heart. To understand PFO, imagine a small flap-like opening between the two upper chambers of the heart, called the atria. This opening, known as the foramen ovale, is essential for fetal circulation. It allows blood to bypass the lungs, which are not yet in use before birth.

Typically, after birth, the lungs take over the job of oxygenating blood, and the foramen ovale closes as it is no longer needed. However, in about 25-30% of people, this opening does not close completely, leaving a small passageway or flap. This condition is called Patent Foramen Ovale, or PFO.

Most individuals with PFO are unaware of its presence because it often doesn’t cause any symptoms. However, PFO can create a potential risk for certain medical conditions. One of the primary concerns is that this small opening can act as a conduit for blood clots or air bubbles to pass from the right side of the heart to the left side. From there, these clots or bubbles can travel to the brain, potentially causing a stroke or other serious health issues.

The connection between PFO and health problems can be subtle. For instance, some people with PFO might experience migraines, especially migraines with aura, more frequently than those without PFO. Others may have transient visual disturbances or unexplained neurological symptoms. In younger individuals, PFO is often considered a possible cause when a stroke occurs without a known reason, termed a cryptogenic stroke.

Diagnosis of PFO typically involves imaging techniques such as echocardiography, which uses sound waves to create pictures of the heart and can reveal the presence of the opening. If PFO is suspected to contribute to medical problems, doctors might recommend treatment. Treatment options include medications to reduce the risk of clot formation or a minimally invasive procedure to close the opening with a special device.

Understanding PFO is crucial because while it is a common and often benign condition, being aware of its existence and potential implications can help in early detection and management of related health issues. By paying attention to the subtle signs and symptoms that might suggest PFO-related complications, individuals and healthcare providers can work together to ensure better health outcomes.

Clinical Implications of Patent Foramen Ovale

PFO is frequently asymptomatic but has been associated with various clinical presentations, ranging from cryptogenic stroke to different embolic events. Notably, patients with cryptogenic stroke have a 2.9 times higher likelihood of having PFO compared to controls. This anomaly may be implicated in approximately two-thirds of cryptogenic stroke cases and potentially up to 80% in younger patients. Understanding the clinical implications of PFO is crucial for early detection and appropriate management, considering its high prevalence and potential morbidity.

Ophthalmological Manifestations of PFO

Ophthalmological manifestations of PFO can include transient visual disturbances, alterations in the visual field, migraines, and other oculomotor signs. These symptoms may prompt patients to seek ophthalmic consultation. Acute retinal ischemic events, such as transient visual loss and retinal artery occlusions, have been described in several studies and case reports. Recognizing these manifestations early can facilitate prompt referral to cardiology, appropriate diagnostic work-up, and consideration for available PFO closure treatment.

Clinical Presentations Leading to Ophthalmological Evaluation

  • Retinal Artery Occlusions: Conditions like central retinal artery occlusion (CRAO) and branch retinal artery occlusion (BRAO) can indicate life-threatening situations. The foremost goal in the acute phase is to promptly restore retinal blood flow to prevent irreversible visual damage. In the subacute phase, the focus shifts to identifying the underlying causative mechanism to prevent further ocular or systemic complications. Ophthalmologists should refer patients to a stroke center for multidisciplinary medical evaluation, including echocardiography and other imaging analyses, especially when the initial examination does not reveal a causative mechanism for embolic disease.
  • Migraine with Aura: PFO has been linked to migraines, particularly those with aura. Although the exact pathophysiological mechanisms remain uncertain, studies have shown a higher prevalence of PFO among migraineurs with aura compared to the general population. While PFO closure has shown contrasting results in managing migraines, considering the low complication rate of the procedure, surgical intervention as secondary prevention is a valid option.
  • Ocular Palsies: Impaired eye movement in the presence of PFO is rarely reported. However, in cases of cryptogenic embolic strokes affecting visual motility-related brain regions, clinical suspicion of PFO should be raised, especially in young patients.
  • Endogenous Endophthalmitis: Accurate diagnostic evaluation is crucial when suspecting endogenous endophthalmitis to identify potential hematogenous spread of microorganisms from a distant source in the body. PFO may elevate the risk of paradoxical embolization, particularly in patients with predisposing factors such as bacterial endocarditis. Despite ongoing debates, the consensus on therapeutic approaches remains elusive. Guidelines suggest pars plana vitrectomy offers the most favorable visual outcomes in cases where visual acuity is limited to light perception, and combining antibiotics via both intravitreal and systemic routes is considered the most effective approach.

Management and Therapeutic Approaches

After diagnosing an ocular embolic event, further investigation, including transthoracic echocardiography (TTE) or transesophageal echocardiography (TEE), is recommended. Once PFO is diagnosed, potential interventional therapies, including PFO closure and medical therapy, should be considered. Studies indicate that percutaneous PFO closure significantly reduces the risk of ischemic recurrences compared to medical therapy, especially in cases of large or moderate shunts. PFO closure has been found to be superior to antithrombotic therapy in preventing stroke recurrence after cryptogenic stroke, despite an increased risk of atrial fibrillation post-surgery.

Oculomics and Systemic Disease Correlation

The correlation between ocular signs and systemic diseases has been well documented. The emerging field of oculomics aims to provide insights into a patient’s overall health by examining the eye’s structure and function, identifying potential risk factors for diseases beyond the eye. Deep-learning algorithms, such as RetiCAC, which uses retinal photographs to predict the presence of coronary artery calcium (CAC), have demonstrated improved cardiovascular risk stratification compared to traditional clinical parameters.

Conclusion

While the direct involvement of ophthalmologists in diagnosing PFO may be limited, their expertise in assessing ocular health and recognizing subtle signs of systemic diseases is invaluable. Collaboration with other specialists, such as cardiologists and neurologists, remains essential for ensuring timely diagnosis, comprehensive evaluation, and appropriate treatment selection. Given the high prevalence of PFO in the general population and its potential morbidity, recognizing the clinical manifestations early can significantly mitigate the associated morbidity burden.


reference link : https://www.mdpi.com/2075-4426/14/7/695

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