Cerebral haemodynamics during carotid angioplasty with flow interruption. The correlation between oximetry and transcranial Doppler ultrasonography

Aims. To determine the correlation between oximetry and transcranial Doppler ultrasonography (TDU) during and following carotid stent-angioplasty with flow interruption, and to evaluate the level of hypoperfusion and its recovery during the procedure Patients and methods. Records were made, prospectively, of the flow rates in the middle cerebral artery and the transcutaneous oxygen saturation of 18 patients who had undergone surgery to perform a carotid stent-angioplasty Monitoring was basal and at 1, 3, 5, 10 and 15 minutes after stopping and opening the flow. Measurements, in units and percentages of change, were stratified by groups as mild, moderate and severe. The agreement between the two tests was studied Results. Occlusion time 8 2 +/- 2 7 minutes Two patients (11 1%) presented cerebral hypoperfusion. Flow was re-established in two patients due to its reaching critical values Mean of the baseline values. 56 3 +/- 11 4 cm/s (TDU) and 67 6 +/- 7 1% (oximetry) The changes in the absolute values and percentages of change between TDU and oximetry were evaluated and results showed an agreement between them in occlusion (rho = 0 8-0 9, p < 0.05), with less association on reestablishing the flow (rho = 0 4-0 8, p < 0 05) In percentages of change there was very good agreement in occlusion (kappa = 08-1, p < 0 05) Agreement was good (kappa = 0 68, p < 0 05) at 1, 3 and 5 minutes after opening up the flow Conclusions. A significant correlation was found between the methods during the interruption of carotid flow, which means they can be used independently Overall, 88 9% remained below the safety threshold for cerebral ischaemia and, given that the procedure can be carried out with brief interruptions, control by oximetry or TDU can be lust as safe in evaluating cerebral ischaemia