The Impact of Cerebral Atherosclerosis According to Location on Prognosis after Coronary Artery Bypass Grafting

Intracranial Atherosclerosis Increases the Risk of Postoperative Stroke After Cardiac Surgery: A Review and Meta-Analysis

BACKGROUND

Postoperative stroke is a devastating complication of cardiac surgery with high morbidity, mortality, and health care cost. Extracranial carotid atherosclerosis (ECAS) is a known risk factor for stroke; however, the impact of intracranial atherosclerosis (ICAS) remains unclear. To our knowledge, this is the first literature review of ICAS in cardiac surgery. We aimed to assess the prevalence, association with postoperative stroke, and perioperative management of ICAS in cardiac surgery.

METHOD

A search was performed to identify studies reporting rates of ICAS and stroke after cardiac surgery. Data extraction and primary outcomes for meta-analysis included the prevalence of preoperative ICAS and the association between ICAS and stroke. Risk ratios (RRs) and 95% confidence intervals (CIs) were pooled by random-effects modelling.

RESULTS

Seventeen studies were reviewed and seven were included in the meta-analysis, comprising 4,936 patients. Prevalence of intracranial atherosclerosis (ICAS) among cardiac surgery patients was 21% (95% CI 13%-32%). Patients with ICAS were more likely to develop postoperative stroke (RR 3.61; 95% CI 2.30-5.67; p<0.001). ICAS was more closely associated with stroke than ECAS. Preoperative brain perfusion single-photon emission computed tomography with acetazolamide challenge, staged intracerebral revascularisation, or conversion to off-pump coronary artery bypass grafting are described management options for ICAS.

CONCLUSION

Patients with ICAS are 3.61 times more likely to develop stroke after cardiac surgery. Known predictors for ICAS can be used to develop risk stratification screening tools. Further research with diverse cohorts is required to develop evidence-based guidelines for screening and management of ICAS in cardiac surgery.

Coronary Artery Magnetic Resonance Angiography Combined with Computed Tomography Angiography in Diagnosis of Coronary Heart Disease by Reconstruction Algorithm

This research aimed at discussing the diagnosis effect of coronary artery magnetic resonance angiography (MRA) combined with computed tomography (CT) angiography (CTA) based on the back-projection filter reconstruction (BPFR) algorithm in coronary heart disease (CHD), and its role in the diagnosis of coronary artery disease (CAD). Sixty patients with CHD were selected and randomly rolled into group A (undergone MRA examination), group B (undergone CTA examination), and group C (undergone MRA + CTA), with 20 cases in each group. Taking the diagnostic results of coronary angiography as the gold standard, the MRA and CTA images were reconstructed using a BPFR algorithm, and a filter function was added to solve the problem of image sharpness. In addition, the iterative reconstruction algorithm and the Fourier transform analysis method were introduced. As a result, the image clarity and resolution obtained by the BPFR algorithm were better than those obtained by the Fourier transform analytical method and the iterative reconstruction algorithm. The accuracy of group C for the diagnosis of mild coronary stenosis, moderate stenosis, and severe stenosis was 94.02%, 96.13%, and 98.01%, respectively, which was significantly higher than that of group B (87.5%, 90.2%, and 88.4%) and group C (83.4%, 89.1%, and 91.5%) (P < 0.05). The sensitivity and specificity for the diagnosis of noncalcified plaque in group C were 87.9% and 89.2%, respectively, and the sensitivity and specificity for the diagnosis of calcified plaque were 84.5% and 78.4%, respectively, which were significantly higher than those in groups B and C (P < 0.05). In summary, the BPFR algorithm had good denoising and artifact removal effects on coronary MRA and CTA images. The combined detection of reconstructed MRA and CTA images had a high diagnostic value for CHD.

Cerebral atherosclerosis and early ischemic stroke after left-sided valve replacement surgery

OBJECTIVE

Studies have rarely investigated whether cerebral atherosclerosis increases the risk of stroke after valve replacement surgery. This study evaluated the influence of cerebral atherosclerosis on the risk of stroke after left-sided valve replacement surgery.

METHODS

Between 2005 and 2015, preoperative magnetic resonance angiography was performed for 2085 patients who underwent left-sided valve replacement surgery in a tertiary single center to assess intracranial and extracranial cerebral atherosclerosis. The severity was retrospectively assessed on the basis of the atherosclerosis score, determined by the number of steno-occlusions of the cerebral arteries and the degree of atherosclerosis. Associations between cerebral atherosclerosis and postoperative stroke (within 30 days) were evaluated; the overall influence of total cerebral atherosclerosis, and the individual effects of intracranial and extracranial cerebral atherosclerosis on the risk of postoperative stroke were assessed using multivariable models.

RESULTS

Preoperative cerebral atherosclerosis was identified in 626 (30.0%) patients, whereas intracranial cerebral atherosclerosis and extracranial cerebral atherosclerosis were identified in 367 (17.1%) and 412 (19.8%) patients, respectively. Stroke occurred in 54 (2.6%) patients, and the total cerebral atherosclerosis score was independently associated with an increased risk of stroke (odds ratio, 1.23; 95% confidence interval, 1.06-1.44). The intracranial cerebral atherosclerosis scores (odds ratio, 1.44; 95% confidence interval, 1.16-1.78), but not the extracranial cerebral atherosclerosis scores, independently predicted the incidence of stroke.

CONCLUSIONS

Intracranial cerebral atherosclerosis was an important predictor of postoperative stroke, suggesting the necessity of further studies on the feasibility of preoperative screening for cerebral atherosclerosis in patients undergoing left-sided valve replacement surgery.