Prevalence of Patent Foramen Ovale De-tected by Transcranial Color Coded Duplex Sonography in Cryp-togenic Stroke Patients

Background/Objectives: Contrast transcranial doppler has been used for detection of right-to-left shunts, such as the patent foramen ovale (PFO). Materials and Methods: All consecutive patients with cryptogenic brain infarction admitted to the Walter Mackenzie Hospital, Canada, during 2003-2004, enrolled in a prospective study. Cryptogenic stroke was determined using a standard battery of diagnostic investigations. Transcranial color coded duplex sonography (TCCDS) with saline contrast was performed with an HP Sono 5500, USA device and a 4MHz linear probe. The middle cerebral artery was insonated at a 50-55 mm depth through a transtemporal window. Microbubble signals were recorded during normal respiration and Valsalva maneuver. Results: 114 patients (70 females, 44 males) with cryptogenic stroke had contrast TCCDS done. PFO was detected in 41 patients (30 females, 11 males; 35.9%). In the overall study group, females were more preponderant to have PFO, however the difference was not significant (P=0.053). The frequency of PFO was not significantly different between age groups =45 years (P = 0.96). Conclusion: PFO detected by TCCD is an age independent factor in cryptogenic stroke, and its detection is more feasible with Valsalva maneuver.