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BACKGROUND: Cognitive dysfunction and cerebral vascular accidents (CVA) remain some of the most devastating problems related to cardiac surgery. Despite the major advances in peri-operative care and operative technique in coronary artery bypass surgery, this cohort of patients appear to have poor cerebral physiologic reserve. The aim of this study was to describe regional cerebral blood flow (rCBF) of patients with coronary artery disease (CAD) referred for coronary artery bypass grafting (CABG).

METHODS: 82 consecutive patients with CAD referred for CABG were enrolled after providing informed consent in an Institutional Review Board approved study. Patients with prior CVA, transient ischemic attacks, head trauma or other neurological afflictions were excluded from the study. We prospectively measured preoperative rCBF using SPECT imaging of twelve regions. Patients were determined to have an abnormal SPECT if rCBF was less than two standard deviations outside the mean of age matched controls.

RESULTS: The mean age was 67.5 (range 34 - 89) years. 22% women and 78% men comprised the study group with known risk factors for atherosclerosis: current tobacco use (30%), hypertension (69%) and diabetes (27%). 75% of the SPECT scans demonstrated abnormal rCBF which were associated with older age (p<0.008) current tobacco use (p<0.005) and diabetes mellitus (p<0.005). The incidence of post-operative CVA was 5% and these occurred only in patients with abnormal rCBF.

CONCLUSION: 75% of patients undergoing CABG have a significant impairment in rCBF compared to published age matched controls. This baseline impairment may contribute to their proclivity for cerebral complications