Diffusion-weighted magnetic resonance imaging for the detection of ischemic brain lesions in coronary artery bypass graft surgery: relation to extracorporeal circulation and heparinization.

AIM

Cognitive decline is a well recognized complication after on-pump coronary artery bypass graft (CABG) surgery. We investigated whether the design of extracorporeal circulation (ECC) and the extent of perioperative heparinization have an impact on neurological dysfunction.

METHODS

Sixty-three CABG surgery patients were randomly perfused with an uncoated ECC-set (group A) or with two different heparin-coated ECC-sets (groups B and C). In groups A and B, systemic heparin was given in doses of 400 IU/kg body weight, whereas group C received 150 IU/kg body weight. ECC sets in group C included a diagonal pump and low priming as opposed to roller pumps in groups A and B. Furthermore, in group C blood contact to surfaces other than endothelium and heparin coated material was eliminated. Brain lesions were detected by diffusion-weighted magnetic resonance imaging (DWI). Neurological complications were assessed clinically until discharge (manifest motoric, sensitive or cognitive disturbance). Biochemical coagulation and inflammation parameters were measured pre-, peri-, and postoperatively.

RESULTS

No major neurological events were observed in either group until discharge. DWIs showed 61 new lesions in 19 of 45 patients who terminated all MRI study procedures. Number and volume of the lesions did not differ between groups (P>0.05). Biochemical and inflammatory parameters showed the expected time courses and variations between groups.

CONCLUSION

Ischemic brain lesions are frequently observed in CABG surgery patients but are neither associated with clinically relevant neurological complications nor with ECC set-up and intraoperative heparin dosage. DWI may help in the development of new surgical strategies to reduce postoperative brain damage.