European journal of vascular surgery
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Redundant length of the cervical part of the internal carotid artery (ICA) is a clear angiographic entity although the clinical significance is uncertain. Transcranial Doppler sonography (TCD) examinations were performed on 15 patients with 23 elongated ICAs. The recordings were obtained with the use of flat 2 MHz probe from the middle cerebral artery (MCA) and the intracranial part of ICA at rest and in eight possible extreme positions of head and neck rotation. ⋯ The mean blood flow velocity in the MCA was 55.8 +/- 6.7 cm s-1 and did not change significantly after head and neck movements (54.9 +/- 7.6 cm s-1). Analysis of 368 one minute recordings from all possible head positions showed no significant changes of blood flow velocity. Rotation of the head and neck has no significant influence on intracranial blood flow velocity in the presence of carotid artery elongation.
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Comparative Study
The assessment of cerebral oxygenation during carotid endarterectomy utilising near infrared spectroscopy.
Near infrared spectroscopy is a non-invasive method for continuous monitoring of tissue oxygenation. In 11 patients undergoing unilateral carotid endarterectomy, changes in cerebral oxygenation following carotid cross-clamping and declamping detected by a near infrared spectrometer were compared with corresponding changes in ipsilateral middle cerebral artery flow velocity measured by transcranial Doppler ultrasonography. Spectroscopic traces were obtained in all patients but adequate Doppler signals in only eight. ⋯ The near infrared spectrometer was also sensitive to the changes in cerebral haemodynamics due to intraoperative hypo- and hypertensive episodes. No evidence of cerebral intracellular hypoxia was seen and all patients made an uneventful recovery. Near infrared spectroscopy compares well with transcranial Doppler ultrasound as a monitor of cerebral function during carotid endarterectomy and may have a future role in the elucidation of cerebral perfusion and oxygenation changes following surgery.
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Intraoperative Duplex examination can be used to identify technical imperfections during carotid endarterectomy. The objectives of this study were: (1) to evaluate the technical feasibility of intraoperative Duplex; (2) to compare Duplex findings with contrast arteriography; (3) to correlate intraoperative Duplex findings with postoperative complications and with Duplex data obtained during follow-up. ⋯ Duplex scanning is easy to use after completion of carotid endarterectomy. There is good agreement between intraoperative Duplex scanning and contrast arteriography. Extensive spectral broadening of the Doppler velocity signal is associated with an increased prevalence of early postoperative complications. Restenosis at follow-up appears to be related to severe flow disturbance as was demonstrated for the external carotid artery.