Changes in Internal Carotid Blood Flow after CEA Evaluated by Transit-time Flowmeter

AbstractAimThe aim of this study was to investigate whether there was an association between the degree of the stenosis of the internal carotid artery (ICA) and post-operative increase of blood flow.Methods and materialsIn 200 out of 660 patients undergoing carotid endarteriectomy (CEA) for a high-degree ICA stenosis, pre-operatively a bilateral selective carotid and intracerebral angiography was performed. The degree of the ipsilateral and contralateral stenosis was digitally assessed by using computer software according to the CC-Index. Intraoperatively, the pressure ratio over the stenosis (ICA/CCA) was measured by direct arterial puncture. Blood flow in the ICA was measured before and after CEA with an ultrasound flowmeter using the transit-time principle. These findings were correlated to the degree of stenosis revealed by angiographic analysis and the pressure ratio.ResultsBefore CEA the median blood flow in the ICA was 171ml/min (range 620ml/min) with a significant (p<0.001) post-operative increase to 250ml/min (range 875ml/min). The median relative increase of flow (post-flow–pre-flow/pre-flow) was 42%. The pre-CEA flow volumes were dependent on the degree of stenosis and also the pressure ratio. The increase of flow following CEA correlated better with pressure ratio (r=−0.435, p<0.001), than the stenosis severity (r=0.319, p