ePTFE-based biomedical devices: An overview of surgical efficiency

Polytetrafluoroethylene (PTFE) is a ubiquitous material used for implants and medical devices in general because of its high biocompatibility and inertness: blood vessel, heart, table jawbone, nose, eyes, or abdominal wall can benefit from its properties in case of disease or injury. Its expanded version, ePTFE is an improved version of PTFE with better mechanical properties, which extends its medical applications. A material as frequently used as ePTFE with these exceptional properties deserves a review of its main uses, developments, and possibility of improvements. In this systematic review, we examined clinical trials related to ePTFE-based medical devices from the literature. Then, we excluded all trials using ePTFE as a control to test other devices. ePTFE-coated stents, hemodialysis and bypass grafts, guided bone and tissue regeneration membranes, hernia and heart repair and other devices are reviewed. The rates of success using these devices and their efficiency compared to other materials used for the same purposes are reported. ePTFE appears to be more or just as efficient compared to them. Some success rates remain low, suggesting the need of improvement ePTFE for medical applications.

Atrial Fibrillation Following Patent Foramen Ovale Closure: Systematic Review and Meta-Analysis of Observational Studies and Clinical Trials

[Figure: see text].

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.