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Methodological Notes
Cerebrovasc Dis 2012;34:314–321
DOI: 10.1159/000343229
Near-Infrared Spectroscopy Can Predict the
Onset of Cerebral Hyperperfusion Syndrome
after Carotid Endarterectomy
C.W.A. Pennekamp
a
R.V. Immink
b
H.M. den Ruijter
e
L.J. Kappelle
c
C.M. Ferrier
d
M.L. Bots
e
W.F. Buhre
b
F.L. Moll
a
G.J. de Borst
a
Departments of
a
Vascular Surgery,
b
Anesthesiology,
c
Neurology and
d
Clinical Neurophysiology, and
e
Julius Center for
Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
ments performed in the first postoperative hour ( V
mean
,
rSO
2
, respectively). Logistic regression analysis was per-
formed to determine the relationship between V and rSO
2
and the occurrence of CHS. Subsequently, receiver operating
characteristic (ROC) curve analysis was used to determine
the optimal cutoff values. Diagnostic values were shown as
positive and negative predictive values (PPV and NPV). Re-
sults: In total, 151 patients were included, of which 7 patients
developed CHS. The V
mean
and rSO
2
differed between
CHS and non-CHS patients (median, interquartile range), i.e.
74% (67–103) versus 16% (–2 to 41), p = 0.001, and 7% (4–15)
versus 1% (–6 to 7), p = 0.009, respectively. The mean arterial
blood pressure did not change. Postoperative V
mean
and
rSO
2
were significantly related to the occurrence of CHS
[odds ratio (OR) 1.40 (95% CI 1.02–1.93) per 30% increase in
V
mean
and OR 1.82 (95% CI 1.11–2.99) per 5% increase in rSO
2
].
ROC curve analysis showed an area under the curve of 0.88
(p = 0.001) for V
mean
and an optimal cutoff value of 67% in-
crease (PPV 38% and NPV 99%), and an area under the curve
of 0.79 (p = 0.009) for rSO
2
and an optimal cutoff value of
3% rSO
2
increase (PPV 11% and NPV 100%). The combination
of both monitoring techniques provided a PPV of 58% and
an NPV of 99%. Conclusions: Both TCD and NIRS measure-
ments can be used to safely identify patients not at risk of
developing CHS. It appears that NIRS is a good alternative
when a TCD signal cannot be obtained.
Copyright © 2012 S. Karger AG, Basel
Key Words
Near-infrared spectroscopy Cerebral hyperperfusion
syndrome Carotid endarterectomy
Abstract
Background: 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 dou-
bling of postoperative transcranial Doppler (TCD)-derived
mean middle cerebral artery blood velocity ( V
mean
) com-
pared to preoperative values. However, in approximately
15% of CEA patients, an adequate TCD signal cannot be ob-
tained due to an insufficient temporal bone window. More-
over, the use of TCD requires specifically skilled personnel.
An alternative and promising technique of noninvasive cere-
bral monitoring is relative frontal lobe oxygenation (rSO
2
)
measured by near-infrared spectroscopy (NIRS), which offers
on-line information about cerebral oxygenation without the
need for specialized personnel. In this study, we assess
whether NIRS and perioperative TCD are related to the onset
CHS following CEA. Methods: Patients who underwent CEA
under general anesthesia and had a sufficient TCD window
were prospectively included. The V
mean
and rSO
2
measured
before induction of anesthesia were compared to measure-
Received: July 19, 2012
Accepted: September 4, 2012
Published online: November 8, 2012
G.J. de Borst, MD, PhD
UMCU, Department of Vascular Surgery (G04.129)
PO Box 85500
NL–3508 GA Utrecht (The Netherlands)
E-Mail G.J.deBorst-2 @ umcutrecht.nl
© 2012 S. Karger AG, Basel
1015–9770/12/0344–0314$38.00/0
Accessible online at:
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