Evaluation of Changes of Systemic Blood Pressure and Shunt Incidence in CEA

BackgroundInduced hypertension is widely recommended as a protective measure in carotid endarterectomy (CEA) to prevent shunt insertion. In this study changes of systemic blood pressure were evaluated in relation to the shunt rate when CEA was performed under local anaesthesia.Materials and methodsIn 930 CEAs performed for a high-grade (>70%) ICA stenosis under local anaesthesia the mean systemic blood pressure was measured preoperatively (RR1) and directly before carotid cross-clamping (RR2). A ratio was calculated from these values (RRR = RR2/RR1). A shunt was only inserted for clinical signs of cerebral ischemia. If that became necessary later after cross-clamping had been tolerated primarily, the blood pressure during this period was also recorded (RR3). Also the presence of a contralateral ICA occlusion and baseline blood pressure levels were considered as factors with potential impact on shunt necessity.ResultsAmong the 638 male (69%) and 292 female (31%) patients with a median age of 70 years (ranging from 52 to 91 years) 82 (9%) had a contralateral ICA occlusion.A shunt was used in 177 operations (19%) and significantly more frequent in patients with a contralateral ICA occlusion (39/82 = 48% vs. 138/848 = 16%, p < 0,001).RRR was significantly reduced in patients who needed a shunt (0.95 (0.41–1.53) vs. 1.0 (0.54–1.9), p = 0.002) which was only true for patients with a patent contralateral ICA.The shunt rate did not differ when contrasting RRR thresholds (<0.7 vs. >1.3) or preoperative blood pressure levels (<100 mmHg vs. >120 mmHg) were compared.RRR did not differ between directly or delayed shunted patients. RR3 did not differ significantly from RR2.A regression analysis identified the presence of a contralateral ICA occlusion as the only independent parameter influencing shunt insertion.ConclusionsChanges in systemic blood pressure during CEA under local anaesthesia seem to influence shunting rather marginally. The value of induced hypertension to prevent cerebral ischemia should be newly discussed.