PP17. Transcranial Doppler Monitoring is Vital in Thoracic Endograft Placement

Thoracic Endograft (TAG) placement has become an acceptable treatment alternative to open surgical repairs. It has been shown that risk factors for developing a stroke during TAG are obesity, blood loss and vascular embolization. Manipulation of the aortic arch during cardiac catheterization has likewise been identified as a source of cerebral embolization. The influences of endograft placement on cerebral embolization and flow is not well described. As such, our aim is to quantify the number of microembolic signals (MES,) velocities (VEL), and pulsatility index (PI) detected by Transcranial Doppler (TCD) during different stages of the endograft placement and correlate them with landing zones, subclavian revascularization and number of devices used. Twenty (20) patients were monitored with TCD during endovascular repair of the thoracic aorta. Imaging and medical parameters were entered into a combined database. We recorded middle cerebral artery (MCA) velocities, pulsatility index (PI) and embolic count. TCD monitoring was successful in all patients. The highest MES counts were generated by the pig tail catheter during the diagnostic stage (DS) and by device placement during deployment phase (DP). Embolic count to right/left (Rt/Lt) sides were the same overall. In DS an average of 8.65 MES were seen Rt/Lt, while during DP 45.40 and 42.68 MES were seen respectively for Rt and Lt. Baseline MCA velocities were similar for Rt and Lt and increased significantly from baseline during balloon inflation from (Rt. 33.5 to 50.2 p-value 0.02; Lt 32.5 to 47.2 p-value 0.001). Similarly, the pulsatility index increased from 0.95 (Rt) and 1.02 (Lt) to 1.43 (Rt) and 1.38 (Lt) (p-value 0.0005 and 0.0009 respectively for Rt and Lt). There was no correlation between post-operative stroke TIA, arch type, landing zone or coverage of the subclavian artery and number of MES. The ability of TCD to detect cerebral emboli and alterations in flow patterns is important to reveal which steps of thoracic endografting are most likely to provoke emboli and hymodynamic changes. It also has a potential to compare endografts and their capacity to generate emboli.