Can a peripheral artery be used to detect venous to arterial circulation shunts?

Background: Transcranial Doppler is a sensitive test for patent foramen ovale (PFO), but an absent temporal window precludes this in 12-15% of patients. We investigated whether the brachial (BrA), common carotid (CCA) or common femoral (CFA) artery provided reliable alternatives. Methods: Patients underwent simultaneous insonation of a middle cerebral artery (MCA, n = 66) and either (a) the BrA (n = 22), (b) CCA (n = 20) or (c) CFA (n = 24) with a 2-MHz transcranial Doppler probe. Results: The correlation between microbubble emboli counts in the MCA and the peripheral arteries was (a) r = 0.67 (95% CI 0.53-0.77) for the BrA, (b) r = 0.80 (95% CI 0.71-0.87) for the CCA and (c) r = 0.92 (95% CI 0.89-0.95) for the CFA. The agreement for detection of PFO was best using the CFA with a kappa of 0.95 (95% CI 0.66-1.0). Conclusion: The CFA is a simple and reliable alternative to the MCA, but the criteria for diagnosis of a PFO are different. Copyright © 2007 S. Karger AG.