Sunday, 4 September 2011

Uncertainties in stroke

Patent Foramen Ovale and cryptogenic stroke

There was a case discussion, at the Friday lunchtime meeting, of a young man with cryptogenic stroke who, on testing, was found to have a patent foramen ovale (PFO). He was offered the option of life-long warfarin or percutaneous closure of the PFO.

The evidence in this area is lacking. [1] PFO is common in the general population and, though a theoretical cause of stroke by paradoxical embolus, it is not proven even with the associated atrial septal aneurysm that may be present.

"Patent foramen ovale, alone or together with ASA, was not associated with an increased stroke risk in this multiethnic cohort. The independent role of ASA needs further assessment in appositely designed and powered studies." [2]

"In patients with otherwise [cryptogenic stroke], approximately one third of discovered PFOs are likely to be incidental and hence not benefit from closure. This probability is sensitive to patient characteristics such as age and the presence of an atrial septal aneurysm, suggesting the importance of patient selection in therapeutic decision-making." [3]

Interestingly the patient presented with a posterior circulation infarct. This is not impossible for an embolus [4] but less likely than a more typical anterior circulation paradoxical embolus. There was also no obvious source of venous thromboembolism either.

Diagram of PFO

Closure may be of benefit [5], and was the option chosen by this patient, but we await the results of more ongoing studies [6] to change the current practice of simply discussing it with the patient and being open about the uncertainty. [7]

(image of patent foramen ovale and percutaneous repair from )

The current NICE guidance includes a useful booklet for patients considering undergoing the procedure.

Arterial pathologies

Another two cases of stroke were presented both of which involved arterial pathology. One of internal carotid artery dissection with pseudoaneuysm and another of vertebral artery dissection. Both had excellent Magnetic Resonance Angiogram images.

This is another area where the best management (antiplatelets vs. anticoagulation, duration of treatment) is awaiting evidence and both patients were enrolled in the CADISS trial. [8]

1. Irwin B, Ray S. Patent Foramen Ovale-Assessment and Treatment. Cardiovasc Ther 2011 Feb; Available from:

2. Di Tullio MR, Sacco RL, Sciacca RR, Jin Z, Homma S. Patent foramen ovale and the risk of ischemic stroke in a multiethnic population. J. Am. Coll. Cardiol 2007 Feb;49(7):797-802. Available from:

3. Alsheikh-Ali AA, Thaler DE, Kent DM. Patent foramen ovale in cryptogenic stroke: incidental or pathogenic? Stroke 2009 Jul;40(7):2349-2355. Available from:

4. Tanaka H, Fujita N, Enoki T, Matsumoto K, Watanabe Y, Murase K, Nakamura H. Relationship between Variations in the Circle of Willis and Flow Rates in Internal Carotid and Basilar Arteries Determined by Means of Magnetic Resonance Imaging with Semiautomated Lumen Segmentation: Reference Data from 125 Healthy Volunteers. AJNR Am J Neuroradiol 2006 Sep;27(8):1770-1775. Available from:

5. Paciaroni M, Agnelli G, Bertolini A, Pezzini A, Padovani A, Caso V, Venti M, Alberti A, Palmiero RA, Cerrato P, Silvestrelli G, Lanari A, Previdi P, Corea F, Balducci A, Ferri R, Falcinelli F, Filippucci E, Chiocchi P, Grandi FC, Ferigo L, Musolino R, Bersano A, Ghione I, Sacco S, Carolei A, Baldi A, Ageno W. Risk of recurrent cerebrovascular events in patients with cryptogenic stroke or transient ischemic attack and patent foramen ovale: the FORI (Foramen Ovale Registro Italiano) study. Cerebrovasc. Dis 2011;31(2):109-116. Available from:

6. Furlan AJ, Reisman M, Massaro J, Mauri L, Adams H, Albers GW, Felberg R, Herrmann H, Kar S, Landzberg M, Raizner A, Wechsler L. Study design of the CLOSURE I Trial: a prospective, multicenter, randomized, controlled trial to evaluate the safety and efficacy of the STARFlex septal closure system versus best medical therapy in patients with stroke or transient ischemic attack due to presumed paradoxical embolism through a patent foramen ovale. Stroke 2010 Dec;41(12):2872-2883. Available from:

7. NICE. Percutaneous closure of patent foramen ovale for the secondary prevention of recurrent paradoxical embolism [Internet]. 2011; Available from:

8. Cervical Artery Dissection in Stroke Study Trial Investigators. Antiplatelet therapy vs. anticoagulation in cervical artery dissection: rationale and design of the Cervical Artery Dissection in Stroke Study (CADISS). Int J Stroke 2007 Nov;2(4):292-296. Available from:

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