Preoperative magnetic resonance angiography findings and postoperative neurological complications in 93 cases of CABG with cardiopulmonary bypass

Between February 1994 and January 1997, 102 of the 146 patients treated by coronary artery bypass grafting (CABG) had undergone magnetic resonance angiography (MRA) of the brain and neck before the operation, and arterial stenosis or occlusion had been detected in 38 (36.9%) of them. Two of these patients had complicating severe calcification of the ascending aorta, and CABG was performed without cardiopulmonary bypass (CPB). Seven patients without stenotic lesions on MRA were also treated by CABG without CPB for other complications. In addition to the 102 patients one patient had been found to have occlusion of the left common carotid artery and poor enhancement of the distal portion, and as a result we switched from CABG to percutaneous transluminal angioplasty (PTCA). We enrolled 93 patients in this study excluding these 10 patients. The patients were distributed into the three groups according to the MRA findings. Group C = no stenotic lesions (58 patients). Group S=stenosis of <70% (26 patients), Group SS = stenosis of ≧70% (9 patients). Enhancement distal to the stenotic or occlusive lesions was good in all patients in group S and SS. We then examined them for the incidence of postoperative neurological complications. There were no significant differences among the three groups in regard to age, male/female ratio, or incidence of hypertension and hyperlipidemia. In Group S, the incidence of diabetes was significantly higher than in the other Groups. The incidence of prior stroke was significantly higher and the number of coronary arteries affected was significantly larger in group SS than the other groups. There were no significant differences among the three groups with regard to intraoperative variables. The lowest mean arterial pressure on CPB was 44.3 ± 7.4 mmHg, 48.0 ± 8.8 mmHg, 46.3 ± 7.8 mmHg in Group C, S, and SS, respectively, In all groups the lowest mean arterial pressure on CPB was below 50 mmHg. There were no significant differences among the three groups with regard to time to awaken and time to extubation. Two patients experienced transient conciousness disturbance after CABG, one in Group C, the other in Group SS, but no new lesions were detected by brain CT. Only one patient, in Group C. suffered a stroke and had a new lesion on brain CT a month after the operation. No strokes occurred in the perioperative period. In nine patients with good enhancement distal to the severe stenotic or occlusive lesion on MRA of the brain and neck the lowest mean arterial pressure on CPB was below 50 mmHg, but there was no postoperative neurological complications due to the low perfusion pressure on CPB. The results of this study suggested that CABG with CPB can be performed safely in patients with good enhancement distal to the stenotic or occlusive lesions on MRA of the brain and neck.