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

OBJECTIVES

to assess whether shunting during carotid reconstruction affects the release of inflammatory mediators from the ipsilateral hemisphere.

MATERIALS AND

METHODS

a catheter was placed in the ipsilateral jugular bulb during carotid endarterectomy (CEA) in 20 patients. Eight patients with ICBP (internal carotid backpressure) <40 mmHg received a shunt during CEA and 12 patients with ICBP >40 mmHg were operated upon without a shunt. Four patients with a carotid body tumour were used as controls. Blood was taken from the catheter as well as from the radial artery; before clamping, 5, 15, 30 min after clamping and 5 min after declamping. The oxygen extraction (AVO(2)) was calculated. Plasma concentrations of interleukin-1beta (IL-1beta), phospholipase A(2)(PLA(2)), thromboxane B(2)(TXB(2)), 6-keto-prostaglandin F1alpha (6-keto-PGF1alpha) and prostaglandin E(2)(PGE(2)) were measured by enzyme-linked immunosorbent assay (ELISA) technique.

RESULTS

all patients had a normal postoperative course except for one patient 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 clamping in patients operated upon without a shunt (p <0.05). This increase was partly recovered to pre-clamp levels 5 min after reperfusion. The extraction remained stable in the non-shunted patients and the control group. The increased extraction in the non-shunted group correlated with increased levels of IL-1beta 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 increased ratio between TXB(2)and 6-keto-PGF1alpha was noted during clamping ( p <0.05) and further increased during reperfusion. The levels of PGE(2)remained stable in both CEA groups. The PLA(2)levels, as well as TXB(2), 6-keto-PGF1alpha and PGE(2)levels, remained unchanged during the procedure in the control group.

CONCLUSIONS

there is a metabolic response to carotid cross-clamping when no shunt is used. However, the clinical significance of this is unclear, since there were no intraoperative strokes.