Feasibility of simultaneous pre- and postfilter transcranial Doppler monitoring during carotid artery stenting

Dual probe transcranial Doppler monitor setup as seen on the patient and as it relates to the carotid artery embolic protection device.

Schematic representation of normal transcranial Doppler (TCD) signals from a transtemporal probe placement. Middle cerebral artery (MCA) (red: 40-60 mm), anterior cerebral artery (ACA) (blue: 60-70 mm), and contralateral ACA (red: 70-80 mm) (Schematic drawing courtesy of Debra Liles Canter.)

Channel 1: Submandibular internal carotid artery (SICA) recording two microembolic signals (MES) (orange arrows). First one on the channel 2 power M-mode Doppler screen (recoding middle and anterior cerebral artery [MCA + ACA]) traveled to ACA (white arrow). Second MES from SICA traveled to MCA (yellow arrow).

Contrast injection is shown as hyperintense signals on the PMD-TCD screen channel 1, in the middle anterior cerebral artery (MCA), during four cardiac cycles and channel 2, in the submandibular internal carotid artery (SICA), during seven cardiac cycles.

On transcranial Doppler (TCD) monitor a microembolic signals (MES) recorded on channel 1 in the submandibular internal carotid artery (SICA) is seen after a delay of a single heartbeat in the middle anterior cerebral artery (MCA) by transtemporal transcranial Doppler (TCD) probe on the lower channel 2.

Using the GORE Neuro Protection System (W.L. Gore and Associates, Flagstaff, Ariz), (A) no microembolic signals (MES) were identified during stent placement (B) deflation of carotid balloon provokes MES.

Graphic display of average microemboli count during stenting with filter protection (A) and GORE Neuro Protection System (W.L. Gore and Associates, Flagstaff, Ariz) (B).

Predilatation with filter protection (shower of microembolic signals [MES] recorded on both channels).