Transcranial Doppler Monitoring in Patients Undergoing Carotid Artery Revascularization – Observations on Cerebral Embolization Patterns

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Introduction/Patient Description

Intraoperative transcranial Doppler (TCD) monitoring allows us to see intracranial blood flow changes related to endovascular and surgical manipulation in real-time. This study evaluates the results of TCD monitoring during transcarotid artery revascularization with flow reversal (TCAR), carotid endarterectomy without shunt (CEA), with shunt (shCEA) and transfemoral carotid artery stenting with distal filter protection (tfCAS).

Methods

Patients, who underwent carotid artery revascularization with TCD monitoring were included. Patient demographics and medical history were registered based on medical documentation. Intraoperative TCD, hemodynamics, fluoroscopy images and surgical manipulation were recorded simultaneously with a four-channel video recording system, and based on the recordings, number of high intensity signals (HITS) and middle cerebral artery (MCA) flow changes were registered. HITS during contrast injections were not involved into the analysis, due to the high number of artifacts. Number of HITS were compared between the four groups, and HITS during predilation/stent deployment/postdilation were compared between the tfCAS and TCAR groups.

Results

Thirty-six patients were involved (mean age 69.5±10.59; 24 male) (9 CEA; 11 shCEA; 4 ftCAS; 12 TCAR). Hypertension and smoking were frequent among the groups. Mean number of HITS for CEA, shCEA, tfCAS and TCAR were 14.44±28.87 (range: 0-90), 21.54±22.14 (range: 3-42), 222±82.27 (range: 153-340) and 35,33±26.24 (range: 2-74) respectively. The mean number of HITS during TCAR were not significantly different compared to CEA or shCEA, but significantly lower than in patients receiving tfCAS (p < 0.01). Procedural phases of predilation, stent deployment and postdilation were associated with significantly higher HITS during tfCAS compared to TCAR (p=0.01, p=0.014, p=0.012 respectively).

Conclusion/Discussion

Number of embolic events during TCAR is comparable with carotid endarterectomy with and without shunt, and associated with a significantly lower number of HITS, when compared to tfCAS with distal filter protection. According to our results TCAR seems to be a safer alternative of tfCAS.

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Presented by

Peter Legeza, Postdoctoral Fellow, Houston Methodist Hospital