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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Blood Flow Velocity, Carotid Artery Diseases, Cerebrovascular Circulation, Endarterectomy, Carotid, Humans, Hypertensive Encephalopathy, Intracranial Hemorrhages, Middle Cerebral Artery, Pulsatile Flow, Regional Blood Flow, Retrospective Studies, Risk Assessment, Risk Factors, Stroke, Time Factors, Treatment Outcome, Ultrasonography, Doppler, Transcranial.
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Do changes in middle cerebral artery velocity after carotid endarterectomy identify patients at high-risk of suffering intracranial haemorrhage or stroke due to hyperperfusion syndrome? Context: To determine if significant increases in middle cerebral artery velocity (MCAV) or pulsatility index (PI) during and immediately after carotid endarterectomy (CEA) were predictive of patients suffering a stroke due to the hyperperfusion syndrome (HS) or intracerebral haemorrhage (ICH). Transcranial Doppler (TCD) mean/peak MCAV and PI were recorded pre-operatively; pre-clamp; 1-min post-declamping; 10-min post-declamping and 30-min post-operatively. The study was divided into two time periods; Group 1 (1995-2007); where there was no formal guidance for managing post-CEA hypertension (PEH) and Group 2 (2008-2012); where written guidelines for treating PEH were available. 11/1024 patients in Group 1 (1.1%) suffered a stroke due to HS/ICH, compared to 0/426 patients (0.0%) in Group 2 (p = 0.02). In Group 1; intra-operative increases >100% in mean/peak MCAV and PI at 1 and 10-min post-clamp release had positive predictive values (PPV) of 1.2%, 6.3% and 20.0% and 2.9%, 8.0% and 16.6% respectively. Post-operatively; a >100% increase in mean and peak MCAV had a PPV of 6.3% and 2.7% respectively.
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We were unable to demonstrate that significant increases in MCAV and PI were able to predict patients at increased risk of suffering a post-operative stroke due to HS or ICH. The provision of written guidance for managing PEH in Group 2 patients was associated with virtual abolition of ICH/HS. Final Decision: no