Stroke is one of the leading causes of death and disability worldwide. Every year, millions of people suffer from strokes which can severely impact their quality of life. While most strokes are caused by blockages or ruptures within blood vessels supplying the brain, around 30% of cryptogenic (unknown cause) strokes may be caused by a cardiac condition known as a patent foramen ovale or PFO. A PFO is a normal opening between the left and right upper chambers of the heart (atria) that usually closes after birth but remains open in around 1 in 4 adults. When a PFO is present, small blood clots can pass from the right to left atrium and travel to the brain causing a stroke.
Over the past few decades, closure of PFO using minimally invasive devices has emerged as an effective treatment strategy for recurrent cryptogenic strokes attributed to a PFO. In this article, we explore the development and use of various PFO closure devices that have revolutionized the management of strokes caused by a PFO.
History and Development of PFO Closure Devices
The link between PFO and cryptogenic strokes was discovered in the 1970s but it was not until the 1990s that the first clinical trials evaluating PFO closure began. Early devices used for PFO closure included umbrella-style devices like the CardioSEAL Septal Occluder and Helex Septal Occluder that were placed via catheter into the heart to cover the PFO. However, these first generation devices were quite large and not well-suited for small PFO anatomy.
Over the next decade, second generation devices were developed that were smaller, had tighter sealing wings/discs and delivery systems allowing more accurate placement. Some of the key second generation devices included Amplatzer PFO Occluder manufactured by St. Jude Medical, Gore Cardioform Septal Occlusion System by WL Gore and Coalescent Helex Septal Reliant Occluder by Vascular Innovations. Large clinical trials demonstrated the safety and effectiveness of these devices in reducing risk of recurrent strokes in patients with PFO.
The Current Landscape of PFO Closure Devices
Presently, the Amplatzer PFO Occluder is considered the gold standard device worldwide and has been used in over 250,000 procedures globally since receiving FDA approval in 2001. The device consists of a nitinol mesh disc on the left atrial side and another on the right atrial side which when deployed seals the PFO. Other commonly used second generation devices include Gore Cardioform PFO Occluder, Abbott Figulla Flex II Occluder and St. Jude Nexus PFO Occluder.
All modern Patent Foramen Ovale (PFO) Closure Devices closure devices are delivered via femoral or jugular vein access using catheter based techniques. Under X-ray guidance, the delivery system is advanced into the heart chambers and the closure device is deployed across the PFO from the right to left atrium. Once deployed, the discs/wings seal the PFO helping to prevent clots from passing through. Major advantages of these devices over open heart surgery include being minimally invasive, having short hospital stays and quick recovery times for patients. Complication rates are also very low when performed by experienced operators.
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