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Home > Vascular Annual Meeting > PP3. Longer Time Interval Between Carotid Cross...

PP3. Longer Time Interval Between Carotid Cross Clamping and Shunting Is Associated with Increased 30-day Stroke/Death Rate

Peter Paul Wisman1, Selma Tromp1, Rudolf Tutein Noltenius2, Frans L. Mol1, Hans Kelder1, Jean-Paul P.M. de Vries1
1St Antonius, Nieuwegein, Netherlands; 2Albert Schweitzer, Dordrecht, Netherlands

OBJECTIVES: The benefit of carotid endarterectomy (CEA) in patients with an (a)symptomatic >70% stenosis has been proven thoroughly. However, 30-day stroke/death rate after CEA is still 1-8%. We evaluated the possible association between the time it took from carotid cross clamping to uninterrupted flow through a carotid shunt (clamp-to-shunt time) and 30-day stroke/death rate in shunt-dependent patients.

METHODS: From Jan. 2002 to July 2008, 851 patients underwent CEA. Patients were shunted selectively when, after clamping the carotid artery, transcranial Doppler (TCD) showed a decrease of >70% of the flow in the ipsilateral middle cerebral artery or when the electroencephalogram (EEG) showed asymmetry or diffuse slowing. Both TCD and EEG were evaluated on-line by a clinical neurophysiologist. All CEAs were performed by experienced vascular surgeons. In the study period 188/851 patients were shunted and their electronic medical files were examined retrospectively. The remaining shunted patients were divided into three groups according to the clamp-to-shunt time; group 1, clamp-to-shunt time between 1-3 min; group 2, 4-6 min and group 3, 7 min or longer. Primary endpoint was the 30-day stroke/death ratio.

RESULTS: 29/188 patients had an inappropriate bone window for TCD and another 3 patients lacked data concerning clamp-to-shunt time. There were no significant differences between the three groups in the following characteristics: sex, age, co-morbidity, patch/no-patch and symptomatic/asymptomatic patients (t-tests). 30-day stroke/death rate increased with longer clamp-to-shunt time: 3,6%, 5,6% and 12,8% in group 1 (n=28), 2 (n=89), and 3 (n=39), respectively. We analyzed this effect using a binary logistic regression model and found a two-tailed p-value of 0,093. The confounding effect of peri-operative microembolic signals and intracranial flow decrease measured by TCD at 1 and 3 minutes after carotid cross clamping was controlled for.

CONCLUSIONS: Longer carotid-clamp-to-shunt time tends to increase 30 day stroke/death rate post-CEA in our selective shunting protocol. When clamp-to-shunt time exceeded 7 minutes, more than 1 out of 8 patients ended with stroke or death. Again, time is brain!

AUTHOR DISCLOSURES: P. Wisman, None; S. Tromp, None; R. Tutein Noltenius, None; F.L. Mol, None; H. Kelder, None; J.P.M. de Vries, None.