Monday, 6 November 2017

Preventing Recurrence of stroke in cryptogenic Stroke patients with PFO closure

Cryptogenic stroke is defined as stroke in which cause is indeterminate or stroke without underlying embolic, ischemic or hypertensive etiology. (1) When a patient comes in with cryptogenic stroke, the treatment is usually similar to stroke with any known cause such as thrombolytics and antiplatelets. For secondary prevention, recommended guidelines include using a single antiplatelet agent such as aspirin or clopidogrel lifelong or combination of any of these with dipyridamole.(2)

Patients with cryptogenic stroke have been found to have increased prevalence of patent foramen ovale (PFO) compared to general population and it's widely attributed to be the underlying cause of cryptogenic strokes. (3) PFO closure was hypothesized to be useful in such patients for secondary prevention. Over the past 3 years, multiple randomized controlled trials were done comparing the efficacy of medical therapy versus PFO closure for prevention of recurrence of stroke in patients with history of cryptogenic stroke. These trials namely RESPECT, CLOSURE I and PC trial compared the use antiplatelets in preventing stroke and compared it to PFO closure therapy. The results were significant when it came to preventing transient ischemic episodes but no conclusion could be made for preventing ischemic stroke.

An important part of these trials was that phycicians treating the pateints were allowed to use antithrombotics as needed in terms of therapy so the medical therapy group was actually comprised of both antiplatelets as well as antithrombotics. In the sub group analyses of these trials, PFO closure was noted to be significant superior to antiplatelet therapy alone. This observation led to two new trials which were recently published in NEMJ. These trials namely, CLOSE and GORE REDUCE trial used antiplatelets exclusively for comparison and thus produced results in favor of PFO closure. In short, based on these trials, PFO closure was found to have significant preventative strength in terms of recurrent strokes in patients with history of cryptogenic stroke. These findings can lead to changes in the guidelines when it comes to secondary prevention of stroke after a cryptogenic stroke episode.

1. Finsterer J. Management of cryptogenic stroke. Acta Neurol Belg. 2010;110(2):135-47.

2. Hong KS. Dual antiplatelet therapy after noncardioembolic ischemic stroke or transient ischemic attack: pros and cons. J Clin Neurol. 2014;10(3):189-96.

3. Tobis MJ, Azarbal B. Does patent foramen ovale promote cryptogenic stroke and migraine headache?. Tex Heart Inst J. 2005;32(3):362-5.