Immediate effects of carotid clamp release on middle cerebral artery blood flow velocity during carotid endarterectomy
| Autor: | A. McL. Jenkins, J. H. McClure, C. V. Ruckley, M. V. Merrick, M. R. Whyman, A. R. Naylor, J. A. W. Wildsmith |
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| Rok vydání: | 1993 |
| Předmět: |
medicine.medical_specialty
medicine.medical_treatment Blood Pressure Hyperemia Carotid endarterectomy Hyperaemia medicine.artery Internal medicine medicine Humans Carotid Stenosis Endarterectomy Carotid business.industry Hemodynamics Brain Blood flow Cerebral Infarction Echoencephalography Transcranial Doppler Clamp Ischemic Attack Transient Reperfusion Injury Middle cerebral artery cardiovascular system Cardiology Vascular Resistance medicine.symptom Cardiology and Cardiovascular Medicine business Blood Flow Velocity Carotid Artery Internal |
| Zdroj: | European journal of vascular surgery. 7(3) |
| ISSN: | 0950-821X |
| Popis: | Transcranial Doppler ultrasound was employed in 44 patients undergoing carotid endarterectomy in order to identify factors associated with the greatest increases in middle cerebral artery blood flow velocity (MCAV) immediately after carotid clamp release and restoration of flow. Previous reports have suggested that such increases might reflect post-ischemic hyperaemia. Overall, the median increase in MCAV on restoration of flow [58 cm/s (95% Cl 44-68)] was greater than the median decrease in MCAV after initial carotid clamping [36 cm/s (95% Cl 26-43), p0.0001]. However, the immediate increase in MCAV tended to be transient and, in one patient, may have represented a hyperaemic response to a haemodynamically induced intraoperative neurological deficit. There was no association between the magnitude of MCAV increase and clinical presentation, degree of carotid stenosis, computed tomography scan findings, type of anaesthesia, nor the presence or absence of impaired cerebral vascular reserve, nor the occurrence of intraoperative air embolisation. The greatest increases in MCAV on clamp release were observed in patients with the greatest decreases in MCAV at clamping and those with the lowest internal carotid artery stump pressures. The most likely explanation for the findings is that they represent a transient hyperaemic response to carotid occlusion. It remains unclear whether this phenomenon is mediated by some degree of ischaemic injury or simply by the effect of a sudden surge of blood through low resistance arterioles that have dilated in order to maintain the collateral circulation during carotid clamping. |
| Databáze: | OpenAIRE |
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