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Open Access Research article

Factors associated with shunt dynamic in patients with cryptogenic stroke and patent foramen ovale: an observational cohort study

Christian Tanislav1*, Maximilian Puille2, Mathias Grebe3, Nicole Sieweke1, Jens Allendörfer14, Wolfgang Pabst5, Manfred Kaps1 and Frank Reichenberger6

Author Affiliations

1 Department of Neurology, Justus Liebig University Giessen, Am Steg 14, Giessen, 35392, Germany

2 Department of Nuclear Medicine, Justus Liebig University Giessen, Friedrichstraße 25, 35392, Germany

3 Department of Cardiology, Justus Liebig University Giessen, Klinkstraße 33, Giessen, 35392, Germany

4 Department of Neurology, Neurologische Klinik Bad Salzhausen, Am Hasensprung 6, Nidda, 63667, Germany

5 Institute for Biomedicine and Epidemiology, Justus Liebig University Giessen, Heinrich-Buff-Ring 44, Giessen, 35392, Germany

6 Department of Respiratory Medicine, Justus Liebig University Giessen, Klinkstraße 33, Giessen, 35392, Germany

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BMC Cardiovascular Disorders 2011, 11:54  doi:10.1186/1471-2261-11-54

Published: 26 August 2011



As previously reported there is evidence for a reduction in right to left shunt (RLS) in stroke patients with patent foramen ovale (PFO). This occurs predominantly in patients with cryptogenic stroke (CS). We therefore analysed factors associated with a shunt reduction on follow-up in stroke patients suffering of CS.


On index event PFO and RLS were proven by transesophageal echocardiography and contrast-enhanced transcranial Doppler-sonography (ce-TCD). Silent PE was proved by ventilation perfusion scintigraphy (V/Q) within the stroke work-up on index event; all scans were re-evaluated in a blinded manner by two experts. The RLS was re-assessed on follow-up by ce-TCD. A reduction in shunt volume was defined as a difference of ≥20 microembolic signals (MES) or the lack of evidence of RLS on follow-up. For subsequent analyses patients with CS were considered; parameters such as deep vein thrombosis (DVT) and silent pulmonary embolism (PE) were analysed.


In 39 PFO patients suffering of a CS the RLS was re-assessed on follow-up. In all patients (n = 39) with CS a V/Q was performed; the median age was 40 years, 24 (61.5%) patients were female. In 27 patients a reduction in RLS was evident. Silent PE was evident in 18/39 patients (46.2%). Factors such as atrial septum aneurysm, DVT or even silent PE were not associated with RLS dynamics. A greater time delay from index event to follow-up assessment was associated with a decrease in shunt volume (median 12 vs. 6 months, p = 0.013).


In patients with CS a reduction in RLS is not associated with the presence of a venous embolic event such as DVT or silent PE. A greater time delay between the initial and the follow-up investigation increases the likelihood for the detection of a reduction in RLS.