Can a Peripheral Artery Be Used to Detect Venous to Arterial Circulation Shunts?

Abstract

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.

Cervical carotid artery: The most dependable alternative for the detection of a right-to-left shunt with transcranial Doppler in patients with insufficient temporal acoustic bone windows?

“…Moreover, they found in patients in whom RLS could be demonstrated, more bubbles in the ICA than in the MCA. These findings offer indeed the submandibular ICA as an alternative in patients with insufficient temporal bone window, similar to other alternatives such as our transforaminal approach [1], or vertebrobasilar recordings [6], or even more peripheral arteries such as the contralateral brachial or femoral arteries [7]. However, whether the submandibular ICA approach is the most dependable, as Dr Topcuoglu suggests, remains an open question since the different alternatives have still not been directly compared.…”

Alternative Ultrasound Windows and Sensitivity of Contrast Transcranial Doppler in Patients with Patent Foramen Ovale

“…For this purpose, transorbital insonation of the carotid siphon was used in this study [1] . Likewise, cervical insonation of the common carotid artery [4] submandibular insonation of the internal carotid artery [5] , transforaminal insonation of vertebral and basilar arteries [6][7][8] or even insonation of more peripheral arteries, such as the contralateral brachial or femoral arteries [9] , can be performed. However, none of the studies tested the utility of these techniques in patients with insufficient transtemporal bone windows.…”

Vertebrobasilar Recording with Contrast Transcranial Doppler in Right-to-Left Shunt Diagnosis

“…We read with interest the article by Daly et al [1] about the diagnosis of a right-to-left shunt (RLS) while studying the common femoral artery using a 2-MHz Doppler probe. The authors observed that the common femoral artery emboli count correlated with the count of simultaneous middle cerebral artery (MCA) insonation, concluding that this approach is a reliable alternative to the MCA examination.…”