The evolving role of echocardiography in the assessment of patent foramen ovale in patients with left-side thromboembolism

Current Challenges and Future Directions in Handling Stroke Patients With Patent Foramen Ovale—A Brief Review

The role of patent foramen ovale (PFO) in stroke was debated for decades. Randomized clinical trials (RCTs) have shown fewer recurrent events after PFO closure in patients with cryptogenic stroke (CS). However, in clinical practice, treating stroke patients with coexisting PFO raises some questions. This brief review summarizes current knowledge and challenges in handling stroke patients with PFO and identifies issues for future research. The rationale for PFO closure was initially based on the concept of paradoxical embolism from deep vein thrombosis (DVT). However, RCTs did not consider such details, limiting their impact from a pathophysiological perspective. Only a few studies explored the coexistence of PFO and DVT in CS with varying results. Consequently, the PFO itself might play a role as a prothrombotic structure. Transesophageal echocardiography thus appears most appropriate for PFO detection, while a large shunt size or an associated atrial septum aneurysm qualify for a high-risk PFO. For drug-based treatment alone, studies did not find a definite superiority of oral anticoagulation over antiplatelet therapy. Remarkably, drug-based treatment in addition to PFO closure was not standardized in RCTs. The available literature rarely considers patients with transient ischemic attack (TIA), over 60 years of age, and competing etiologies like atrial fibrillation. In summary, RCTs suggest efficacy for closure of high-risk PFO only in a small subgroup of stroke patients. However, research is also needed to reevaluate the pathophysiological concept of PFO-related stroke and establish strategies for older and TIA patients and those with competing risk factors or low-risk PFO.

Patent foramen ovale-When to close and how?

Closure of a patent foramen ovale (PFO) in patients after cryptogenic/cardioembolic stroke is recommended by current guidelines for patients who are 16-60 years of age with a high-risk PFO (class of recommendation A, level of evidence I). The use of double-disk occlusion devices followed by antiplatelet therapy is recommended. The procedure of interventional PFO closure compared with other interventions in cardiology is rather easy to learn. However, it should be performed carefully to avoid postinterventional complications. The number needed to treat (NNT) to avoid one stroke in 5 years in the RESPECT trial was 42, in the CLOSE trial even lower with 20. In the REDUCE trial, the NNT was 28 at 2 years. This can be reduced by longer follow-up, e.g., at 10 years the NNT is 18. While other conditions such as migraine are currently under investigation with respect to the impact of PFO closure, sufficiently powered trials are lacking so that closure in diseases other than stroke should always be individualized.