An observational study of pre-operative transcranial Doppler examinations to predict cerebral hyperperfusion following carotid endarterectomies

Abstract

The objective of this observational study was to determine whether pre-operative transcranial Doppler measurements could identify patients at risk for early cerebral hyperperfusion following carotid endarterectomies. Fifty-five patients (mean age 64.4 years) with symptomatic internal carotid artery stenosis were included. Pre-operative transcranial Doppler measurements included middle cerebral artery blood flow velocities at normocapnia, pulsatility indices and estimation of the cerebro-vascular reserve capacity ipsilateral to the internal carotid artery stenosis. The percentage change in blood flow velocities before and at the end of the procedure was calculated. Early cerebral hyperperfusion was defined as an increase of mean blood flow velocity of more than 100% at the end of the carotid endarterectomy. Early cerebral hyperperfusion was observed in 9.2%. Cerebral hyperperfusion was seen in patients with a subtotal carotid artery stenosis in combination with reduced pre-operative blood flow velocity and pulsatility. The post-operative stroke incidence in patients with an early cerebral hyperperfusion was tenfold higher compared to patients who did not experience early hyperperfusion. A prospective clinical trial is warranted to determine whether transcranial Doppler parameters can be used to indicate patients at risk for reperfusion strokes following carotid endarterectomies.

Diagnostic Impact of Transcranial Color-Coded Real-Time Sonography With Echo Contrast Agents for Hyperperfusion Syndrome After Carotid Endarterectomy

“…In previous studies using TCD, the diagnostic criterion of hyperperfusion syndrome was mostly a Ն2-fold increase in MCA peak systolic or MFV after CEA. 3,4,6 In this study, an MFV ratio of Ն1.5 within 4 postsurgical days yielded a sensitivity of 100% and a specificity of 84%. An MFV ratio of Ն1.4 the next morning after CEA was another indicator that predicted hyperperfusion syndrome perfectly, although its specificity was relatively low (67%).…”

“…[3][4][5][6] However, because of questions regarding accuracy of TCD in diagnosing hyperperfusion syndrome, some controversy remained. Because precise placement of the sample volume as well as angle correlation is not possible by means of the TCD technique, TCD cannot determine absolute MCA flow velocity values.…”

“…[3][4][5][6] However, the accuracy of TCD for measuring MCA flow velocity remained controversial. One can more readily and confidently identify particular vascular structure with transcranial color-coded real-time sonography (TCCS) than with TCD.…”

Status Epilepticus Due to Hyperfusion Injury Post Cardiac Surgery

“…Other authors suggest it is a cerebral flow rate that is "a major increase…well above the metabolic demands of brain tissue" 8 . Although rates of occurrence vary in the literature, some estimate that as many as 14% of carotid endarterecomy cases are complicated by this hemodynamic phenomenon, although only a very small minority, typically 0.5-3%, become symptomatic 3,9 . Rates of hyperperfusion during and after cardiac surgery, especially following cardio-pulmonary bypass procedures, are unknown.…”

Cerebral Hyperperfusion Syndrome After Angioplasty

“…We will also discuss a 11 increased the risk of intracranial hemorrhage (ICH) Macfarlane et al, 1991;Ouriel et al, 1999;Sbarigia et al, 1993). Preoperative significant reduction in flow velocity compared with baseline values is indicative of hypoperfusion and is associated with postoperative hyperperfusion (Keunen et al, 2001). Sudden revascularization brought about by angioplasty leads to dysfunction of the bloodbrain barrier after the failure of arteriolar vasoconstriction.…”