Diagnosis of Right-to-Left Shunt: Possible Alternative Approaches

Abstract

Diagnosis of Right-to-Left Shunt: Possible Alternative ApproachesTo the Editor:We read with great interest the recent article by Del Sette et al 1 about diagnosis of right-to-left shunt with vertebrobasilar doppler examination.So far, neurologists used transtemporal recordings based on the manuscript by Teague and Sharma. 2 The emboli detection is in fact limited by insufficient temporal bone window in 10% to 20% of stroke patients. 3 A probably even greater limitation is the lack of transcranial examination expertise in local hospitals treating stroke patients. 4 Unfortunately, this issue cannot be solved by a transnuchal emboli detection technique.Recordings at the common carotid artery should be considered as a possible alternative technique. This method was already described by Draganski et al in 2005 5 but did not find its way into broad clinical practice. Performance and visualization of highintensity transient signals using contrast-enhanced harmonic carotid duplex and Doppler sonography are simple. Findings in a patient with a patent foramen ovale can be seen in the Figure. It might turn into a feasible option for local hospitals and for patients without a sufficient acoustic bone window in stroke centers if sensitivity and specificity will turn out to be comparable to the established methods. DisclosuresNone.

Right‐to‐left shunt detection using transforaminal insonation of the basilar artery

“…However, this method of TCD detection for RLS is limited by distortion of anatomy and motion in the submandibular area with Valsalva. The value of common carotid insonation for RLS detection has been suggested, but has yet to be evaluated in a study 18 . Transorbital Doppler and monitoring of the carotid siphon has also been investigated, with results showing similar excellent sensitivity and specificity when compared to standard TCD MCA monitoring (97% and 95%, respectively) 19 .…”

“…The value of common carotid insonation for RLS detection has been suggested, but has yet to be evaluated in a study. 18 Transorbital Doppler and monitoring of the carotid siphon has also been investigated, with results showing similar excellent sensitivity and specificity when compared to standard TCD MCA monitoring (97% and 95%, respectively). 19 However, it should be noted that these studies were not completed in patients with inadequate temporal bone windows and used standard TCD monitoring as the reference standard, which may not account for alternative causes of right to left shunt, including pulmonary shunts.…”