Patent Foramen Ovale Closure With the SeptRx Device

Patent foramen ovale and atrial fibrillation as causes of cryptogenic stroke: is treatment with surgery superior to device closure and anticoagulation? A review of the literature

Closure of persistent foramen ovale (PFO) to avoid cryptogenic strokes is performed globally with enthusiasm but lacks prove of efficacy. We present a 79-year-old man who had had a PFO device introduced nine years previously because of cryptogenic strokes presenting as syncopes. The patient was referred from his general practitioner with two new syncopes. Transthoracic echocardiography revealed no cardiac causes of embolism. Transesophageal echocardiography (TEE) revealed a misplaced device like an umbrella in a storm, but no septum defects. Holter revealed seconds-long episodes of atrial fibrillation (AF). The patient was successfully treated with anticoagulation.

A literature review showed that: (i) the efficacy of PFO closure devices has not been proven in any trial, but was demonstrated in a meta-analysis comparing three different devices; (ii) PFO devices are rarely controlled by TEE during or after insertion; (iii) residual shunts are detected in up to 45% of cases; (iv) there is an increased rate of post-arrhythmic complications; (v) the risk of AF in congenital heart disease increases with increasing age, with a 13% risk of transient ischemic attacks and stroke; and (vi) surgical treatment of PFO was found to have a 4.1% risk of complications including stroke.

The question to be asked is whether device closure of PFO should be avoided, considering that PFO is a congenital heart defect with risks of AF and (cryptogenic) stroke? Heart surgery should be a treatment option for symptomatic PFO.

Closure of patent foramen ovale or medical therapy alone for secondary prevention of cryptogenic cerebrovascular events

AIMS

About one-third of ischemic stroke are cryptogenic. Paradoxical embolism through patent foramen ovale (PFO) has been identified as a possible cause of cryptogenic stroke. Therefore, PFO closure has been considered for secondary prevention of cryptogenic stroke. However, randomized clinical trials (RCTs) comparing PFO closure versus medical therapy led to conflicting results. Our objectives were to examine if PFO closure is superior to medical therapy alone for secondary prevention of cryptogenic stroke and to investigate whether PFO closure is associated with an increased incidence of atrial fibrillation/atrial flutter (AFL).

METHODS

The authors systematically searched MEDLINE for RCTs that compared PFO closure with medical therapy. Efficacy outcome was cerebrovascular event (CVE) recurrence and safety outcome was new-onset atrial fibrillation/AFL. The outcomes of interest were investigated according to device type with subgroup analyses and meta-regression.

RESULTS

The authors included eight RCTs constituting 4114 patients. Patients who underwent PFO closure had a lower risk of CVE recurrence compared with medically treated patients [relative risk (RR): 0.56; 95% confidence interval (CI) 0.40-0.80; P = 0.001; I = 30%]. This protective effect was consistent across the different device types. Patients who underwent PFO closure developed more frequently atrial fibrillation/AFL (RR 4.96; 95% CI 2.74-8.99; P < 0.00001; I = 0%), which was mainly transient and within 1 month. Atrial fibrillation/AFL risk was consistent according to device types, although marginally significant in the Amplatzer subgroup.

CONCLUSION

PFO closure might have a role in secondary CVE prevention of patients with PFO and cryptogenic stroke. However, it is associated with an increased incidence of new-onset atrial fibrillation/AFL especially within 1 month.

[Interventional closure of atrial septal defects, patent oval foramen and ventricular septal defects]

Percutaneous transcatheter closure techniques and devices for congenital intracardiac shunts have considerably improved; therefore, catheter closure is now the treatment of choice for atrial septal defects (ASD). This is technically feasible in more than 80% of patients with a secundum ASD and the success rate is higher than 99%. General anesthesia is as a rule unnecessary and the hospital stay is very short. A patent oval foramen (POF) is a potential cause of cryptogenic stroke and peripheral embolisms. The catheter occlusion has many advantages in comparison to lifelong anticoagulation therapy and for some patients it is the only therapeutic option. Randomized trials have shown that interventional closure leads to results which are comparable to drug therapy and for some occlusion systems even evidence of significant advantages compared to drug therapy was found. Even ventricular septal defects (VSD), including perimembraneous and post-myocardial infarction VSDs can be closed by catheter techniques with a high success rate.

Patent foramen ovale

Patent foramen ovale (PFO) is the most common congenital heart abnormality of fetal origin and is present in approximately ∼25% of the worldwide adult population. PFO is the consequence of failed closure of the foramen ovale, a normal structure that exists in the fetus to direct blood flow directly from the right to the left atrium, bypassing the pulmonary circulation. PFO has historically been associated with an increased risk of stroke, the mechanism of which has been attributed to the paradoxical embolism of venous thrombi that shunt through the PFO directly to the left atrium. However, several studies have failed to show an increased risk of stroke in asymptomatic patients with a PFO, and the risk of stroke recurrence is low in patients who have had a stroke that may be attributed to a PFO. With the advent of transoesophageal and transthoracic echocardiography, as well as transcranial Doppler, a PFO can be routinely detected in clinical practice. Medical treatment with either antiplatelet or anticoagulation therapy is recommended. At the current time, closure of the PFO by percutaneous interventional techniques does not appear to reduce the risk of stroke compared to conventional medical treatment, as shown by three large clinical trials. Considerable controversy remains regarding the optimal treatment strategy for patients with both cryptogenic stroke and PFO. This Primer discusses the epidemiology, mechanisms, pathophysiology, diagnosis, screening, management and effects on quality of life of PFO.