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

Impact of preexisting cerebral ischemia detected by magnetic resonance imaging and angiography on late outcome after coronary artery bypass surgery

BACKGROUND

The aim of this study was to assess the impact of preexisting ischemia detected by brain magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) on long-term survival, and cardiac and neurologic events after coronary artery bypass grafting (CABG).

METHODS

Of 923 patients who underwent CABG between 1994 and 2007, 887 patients (96.1%) were followed up. Preoperative brain MRI and MRA were performed in 619 patients. Ischemia was detected by brain MRI and MRA in 158 patients (group A), but not in 461 patients (group B). Preoperative characteristics, follow-up survival, and cardiac and neurological events were investigated.

RESULTS

The average follow-up period was 6.0 ± 4.3 years. Univariate analysis showed that patients in group A (68.5 ± 6.5 years) were older than those in group B (64.5 ± 8.6 years) (p = 0.0001). Preoperative left ventricular ejection fraction was less in group A (0.516 ± 0.175) than in group B (0.556 ± 0.165) (p = 0.02). The prevalence of peripheral vascular disease was higher in group A (14 patients: 8.9%) than in group B (11 patients: 2.4%) (p = 0.001). The rate of on-pump CABG was lower in group A (115 patients; 72.8%) than in group B (383 patients; 83.1%) (p = 0.007). Survival rate was significantly lower (p = 0.062), and freedom from major adverse cardiac event or stroke were significantly lower in group A (p = 0.0002, and p = 0.0001, respectively; log-rank test). However, the Cox proportional hazard model showed that preoperative brain ischemia detected by brain MRI and MRA affected only freedom from neurologic events (p = 0.02; hazard ratio 2.52; 95% confidence interval 1.13 to 5.62), but not survival (p = 0.67) or major adverse cardiac event (p = 0.09).

CONCLUSIONS

Preexisting ischemic findings on brain MRI and MRA in patients who underwent CABG were related only to long-term freedom from stroke, but were not related to survival or major adverse cardiac event.

Intracranial cerebral artery disease as a risk factor for central nervous system complications of coronary artery bypass graft surgery

BACKGROUND AND PURPOSE

Although extracranial carotid artery disease (ECAD) is accepted as a risk factor for central nervous system (CNS) complications after coronary artery bypass graft (CABG) surgery, it remains to be clarified whether intracranial cerebral artery disease (ICAD) may also increase the risk. We conducted a prospective study to elucidate the relation between ICAD and CNS complications after CABG surgery.

METHODS

We prospectively studied 201 patients undergoing nonemergency isolated CABG surgery during a 39-month period (from March 1995 to June 1998). Each patient was evaluated before surgery with neurological examination, transcranial Doppler, and carotid duplex ultrasonography. Magnetic resonance angiography was used to determine the presence and severity of ECAD and ICAD in patients with abnormal findings on clinical examination, carotid duplex ultrasonography, or transcranial Doppler. Patients were followed after surgery and evaluated for the development of CNS complications. Association between CNS complications and their potential predictors was analyzed.

RESULTS

One hundred nine patients (54.2%) were found to have ECAD and/or ICAD. ECAD alone was found in 48 patients (23.9%), ICAD alone in 33 (16.4%), and both ECAD and ICAD in 28 (13.9%). Fifty-one patients (25.4%) had single or multiple CNS complications: 23 (11.4%) had delirium; 18 (9.0%) had hypoxic-metabolic encephalopathy; 7 (3.5%) had stroke; and 7 (3. 5%) had seizure. In multivariate analysis, ICAD was found to have an independent association with the development of CNS complications (prevalence OR, 2.28; 95% CI, 1.04 to 5.01) after controlling for covariates including age, occurrence of intraoperative events, and reoperation. The joint effect of ECAD and ICAD was also statistically significant and stronger than ICAD alone (prevalence OR, 3.87; 95% CI, 1.80 to 6.52).

CONCLUSIONS

Our results suggest that ICAD may be an independent risk factor for CNS complications after CABG surgery. These results support pre-CABG evaluation of the intracranial arteries for the risk assessment of CABG surgery, at least in black and Asian patients, in whom there may be a higher prevalence of intracranial arterial stenosis.