Cerebrovascular resistance and blood flow velocity changes after carotid endarterectomy

Background: To study the pattern of cerebral blood flow velocity and cerebr al resistance changes after carotid endarterectomy. Patients and methods. In 81 patients (mean age +/- SD, 64 +/- 8 years) with unilateral carotid endarterectomy (CEA) the systolic, diastolic and mean b lood velocities, and the pulsatility index (PI) were recorded in both middl e cerebral arteries preoperatively and repetitively postoperatively with th e use of transcranial Doppler ultrasound (TCD). Results: In the middle cerebral artery ipsilateral to CEA mean blood veloci ty was increased 6 hours (64 +/-: 25 cm/sec; p < 0.005) and 7 days (54 +/- 15 cm/sec; p < 0.05) after CEA and had returned to the preoperative level ( 49 +/- 11 cm/sec) after 3 months. Compared to preoperatively (0.86 +/- 22), the PI was significantly increased at 6 hours examination (1.03 +/- 23, p < 0.005), and remained increased thereafter. A patho-logically increased me an blood velocity (> 83 cm/sec) 6 hours after CEA occurred in 11 patients, two of them developed a slight hyperperfusion syndrome. In the contralatera l middle cerebral artery, only the diastolic blood velocity showed signific ant changes (preoperatively; 35 +/- 12 cm/sec; 3 months after CEA, 33 +/- 8 cm/sec p < 0.05). Conclusions: Using TCD, hemodynamic changes occur predominantly in the midd le cerebral arteries ipsilateral to CEA. Early postoperative TCD studies ma y be of help to identify patients at risk to develop a hyperperfusion syndr ome.