Claire W. Pennekamp, Hester den Ruijter, Rogier Immink, L. Kappelle, Frans L. Moll, Wolfgang Buhre, Cyrille Ferrier, Gert-Jan de Borst
Vascular Surgery, UMCU, Utrecht, The Netherlands.
OBJECTIVES: Cerebral hyperperfusion syndrome (CHS) after carotid endarterectomy (CEA) is a potential life-threatening complication. Therefore, early identification and treatment of patients at risk is essential. CHS can be predicted by a doubling of postoperative transcranial Doppler (TCD) derived middle cerebral artery blood velocity (V) as compared to pre-operative values. However, in ~15% of CEA patients an adequate TCD-signal cannot be obtained due to an insufficient temporal bone window. Near infrared spectroscopy (NIRS), estimating the frontal lobe oxygenation (rSO2) could be used as an alternative cerebral monitoring technique. We assessed the value of NIRS and peri-operative TCD to predict CHS after CEA.
METHODS: In total, 151 consecutive patients undergoing CEA under general anesthesia having a sufficient TCD window were prospectively included. V and rSO2 measured before induction of anesthesia were compared to measurements in the first postoperative hour (ΔV, ΔrSO2 respectively). Logistic regression analysis was performed to determine the relationship between ΔV and ΔrSO2 and the occurrence of CHS. ROC curve analysis was used to determine the optimal cut-off values.
RESULTS: Seven patients developed CHS. ΔV and ΔrSO2 differed between CHS and non-CHS patients (mean±SD), i.e. 63±29% vs. 24±45% and 9±6% vs. 1±9% respectively (p<0.05). Increases in ΔV and ΔrSO2 were significantly associated with the occurrence of CHS, independent of age and gender, OR 1.47 (95% CI 1.04-2.09) per 30% increase in V and OR 1.77 (1.06-2.96) per 5% increase in rSO2. ROC curve analysis showed an AUC of 0.843 for ΔV and an optimal cut-off value of 62% increase (PPV 0.31, NPV 0.98). And an AUC of 0.793 for ΔrSO2 and an optimal cut-off value of 3% rSO2 increase (PPV 0.10, NPV 0.99).
CONCLUSIONS: Both TCD and NIRS seem to be useful to safely exclude patients from being at risk to develop CHS. However, due to the limited number of CHS cases our results need to be validated in a larger study.
AUTHOR DISCLOSURES: W. Buhre, Nothing to disclose; G. de Borst, Nothing to disclose; H. den Ruijter, Nothing to disclose; C. Ferrier, Nothing to disclose; R. Immink, Nothing to disclose; L. Kappelle, Nothing to disclose; F. L. Moll, Nothing to disclose; C. W. Pennekamp, Nothing to disclose.
Posted April 2012