Prevalence of right-to-left shunts in active fighter pilots

BACKGROUND: Patent foramen ovale (PFO) is a risk factor for cerebrovascular accidents and provides a potential mechanism for paradoxical systemic embolization of venous gas bubbles produced after altitude decompression. The objective of the study is to describe the prevalence of PFO and of possible subsequent brain lesions in active military fighter pilots. METHODS: A sample of 52 healthy active fighter pilots was assessed with transcranial Doppler sonography, transesophageal echocardiography, and cranial MRI. RESULTS: Significant right to left shunting occurred in 17% (9/52; 95% CI 8.7% to 30.8%); all shunts were due to a PFO. Cranial MRI was normal in each case. CONCLUSION: In this sample, prevalence of PFO lies within the expected range. There is no evidence that military flying in pilots who carry PFOs leads to brain damage. Screening for PFO is not recommended.