The patent foramen ovale (PFO) is frequently associated with cryptogenic stroke. PFO is present in about 25 percent of the population, but is not harmful to the vast majority. Even as the evidence surrounding this congenital condition expands, practitioners find themselves clashing on if and how to treat this common heart defect.
Currently no devices are approved in the U.S. for PFO closure, but off-label devices approved for atrial septal defect (ASD) are being widely used. Percutaneous PFO closure has been generally limited to recurrent cryptogenic stroke patients who have failed conventional drug therapy; however, recent evidence for other indications has arisen, but has not yet been proven with randomized controlled trials.
This field is continuously surrounded by debatable questions such as: what is the most optimal treatment strategy for a PFO? What role does the PFO play in cryptogenic stroke? Should a PFO be closed if discovered incidentally during surgery? And, should PFO closure be used for migraine relief? These questions remain unanswered.
To close or not to close?
The prospective, randomized CLOSURE I trial in 2009 randomized 909 cryptogenic stroke or transient ischemic attack (TIA) patients with a PFO to receive closure with the STARFlex septal closure device plus medical therapy (447 patients) or medical therapy—24-month aspirin or warfarin or combination—alone (462 patients) to measure the prevention of recurrent stroke or TIA (Stroke 2010;41:2872-2883).
CLOSURE I researchers found no increased benefit of combining PFO closure and medical therapy and reported that two-year primary composite endpoints were similar for both groups, 5.9 percent in the STARFlex arm vs. 7.7 percent in the medical therapy arm.
The lackluster results of CLOSURE I have left some clinicians questioning whether percutaneous closure of the PFO is advisable in any situation due the high rates of vascular complications, atrial fibrillation (AF) and major bleeds found in the device arm. The rates of AF and bleeding for percutaneous closure and medical therapy compared with medical therapy alone were 5.7 vs. 0.7 percent and 2.6 vs. 1.1 percent, respectively. Major vascular complications occurred at a rate of 3.2 percent in the device arm vs. 0 percent in the medical therapy arm.
Despite the higher complication rates in the device group, Anthony J. Furlan, MD, principal investigator of CLOSURE I and chair of the department of neurology at the University Hospitals Case Medical Center in Cleveland, says, "It would be incorrect to say that CLOSURE I proved that there is no indication for closure, but the indications may be very limited."
Even while PFO closure may have limited indications and its benefits go unverified, a 2008 letter by Opotwsky et al in JAMA noted that PFO/ASD closure is common for these defects and has outpaced surgery as the method of choice ( JAMA 2008;299(5):521-522).
In fact, the researchers reported that percutaneous PFO/ASD closure procedures increased 58-fold over the six-year study period, while the annual number of PFO/ASD closure procedures increased 50-fold. The percentage of closure procedures performed for these congenital heart defects increased from 18.5 percent to 92.5 percent.
The authors deemed the increase in PFO closure "concerning," due to the lack of data, "especially in regards to PFO closure for cryptogenic stroke and migraine headache."
But, the increased interest for PFO closure may spawn from the fact that more than 90 percent of patients go home within the same day of procedure, and there is no need for life-long anticoagulation therapy like warfarin, where frequent blood checks are necessary.
Richard Krasuski, MD, director of Adult Congenital Heart Disease Services at the Cleveland Clinic, evaluates four to five patients per week referred to him with PFO, and in 80 percent of cases, he recommends against closure.
In most cases, Krasuski prescribes PFO patients a baby aspirin to reduce clotting risk, particularly if patients have no other alarming symptoms. However, he says that there is currently no evidence to support or refute this strategy in patients without a prior event.
Only about 20 percent of the patients with PFOs treated at Cleveland Clinic will undergo percutaneous closure, due to the fact that in most cases patients fall outside guidelines and don't have symptoms suggesting a prior neurological event, thus making device closure an unnecessary method of treatment, says