Maintaining carotid flow by shunting during carotid endarterectomy diminishes the inflammatory response mediating ischaemic brain injury

Objectives: to assess whether shunting during carotid reconstruction affect s the release of inflammatory mediators from the ipsilateral hemisphere. Materials and methods: a catheter was placed in the ipsilateral jugular bul b during carotid endarterectomy (CEA) in 20 patients. Eight patients with I CBP (internal carotid backpressure) <40 mmHg received a shunt during CEA an d 12 patients with ICBP >40 mmHg were operated upon without a shunt. Four p atients with a carotid body tumour were used as controls. Blood was taken f rom the catheter as well as from the radial artery; before champing, 5, 15, 30 min after clamping and 5 min after declamping. The oxygen extraction (A VO(2)) was calculated. Plasma concentrations of interleukin-1 beta (IL-1 be ta), phospholipase A(2) (PLA(2)), thromboxane B-2 (TXB2), 6-keto-prostaglan din F-1, (6-keto-PGF(1),) and prostaglandin E-2 (PGE(2)) were measured by e nzyme-linked immunosorbent assay (ELISA) technique. Results: all patients had a normal postoperative course except for one pati ent in the no-shunt group, who suffered a stroke 1 h later due to occlusion of the endarterectomy site. The AVO(2) extraction increased during clampin g in patients operated upon without a shunt (p<0.05). This increase was par tly recovered to pre-clamp levels 5 min after reperfusion. The extraction r emained stable in the non-shunted patients and the control group. The incre ased extraction in the non-shunted group correlated with increased levels o f IL-1 beta during clamping (p<0.05) and reperfusion (p<0.01). PLA(2) also increased during reperfusion in the non-shunted group (p<0.05). An increase d ratio between TXB2 and 6-keto-PGF(1), was noted during clamping (p<0.05) and further increased during reperfusion. The levels of PGE(2) remained sta ble in both CEA groups. The PLA(2) levels, as well as TXB2, 6-keto-PGF(1), and PGE(2) levels, remained unchanged during the procedure in the control g roup. Conclusions: there is a metabolic response to carotid cross-clamping when n o shunt is used. However, the clinical significance of this is unclear, sin ce there were no intraoperative strokes.