Research

Lack of association between right-to-left shunt and cerebral ischemia after adjustment for gender and age

Holger Poppert¹ , Melanie Morschhaeuser¹ , Regina Feurer¹ , Angelina Bockelbrink² , Jens Schwarze³ , Lorena Esposito¹ , Peter Heider⁴ , Dirk Sander⁵ and Bernhard Hemmer¹

¹  Department of Neurology, Klinikum Rechts der Isar, Technische Universitaet Muenchen, Ismaningerstr. 22, 81675 Muenchen, Germany

²  Department of Social Medicine, Epidemiology and Health Economics, Charité – University Medicine Berlin, Luisenstr. 57, 10117 Berlin, Germany

³  Department of Neurology, Klinikum Chemnitz, Flemmingstraße 2, 09116 Chemnitz, Germany

⁴  Department of Vascular Surgery, Klinikum Rechts der Isar, Technische Universitaet Muenchen Ismaninger Str. 22, 81675 Muenchen, Germany

⁵  Neurologische Klinik Medical Park Loipl, Thanngasse 15, 83483 Bischofswiesen, Germany

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Journal of Negative Results in BioMedicine 2008, 7:7doi:10.1186/1477-5751-7-7

Published:	13 October 2008

Abstract

Introduction

A number of studies has addressed the possible association between patent foramen ovale (PFO) and stroke. However, the role of PFO in the pathogenesis of cerebral ischemia has remained controversial and most studies did not analyze patient subgroups stratified for gender, age and origin of stroke.

Methods

To address the role of PFO for the occurrence of cerebral ischemia, we investigated the prevalence of right-to-left shunt in a large group of patients with acute stroke or TIA. 763 consecutive patients admitted to our hospital with cerebral ischemia were analyzed. All patients were screened for the presence of PFO by contrast-enhanced transcranial Doppler sonography at rest and during Valsalva maneuver. Subgroup analyses were performed in patients stratified for gender, age and origin of stroke.

Results

A right-to-left shunt was detected in 140 (28%) male and in 114 (42%) female patients during Valsalva maneuver, and in 66 (13%) and 44 (16%) at rest respectively. Patients with right-to-left shunt were younger than those without (P < 0.001). PFO was associated with stroke of unknown origin in male (P = 0.001) but not female patients (P > 0.05). After adjusting for age no significant association between PFO and stroke of unknown origin was found in either group.

Conclusion

Our findings argue against paradoxical embolization as a major cause of cerebral ischemia in patients with right-to-left shunt. Our data demonstrate substantial gender-and age-related differences that should be taken into account in future studies.