Impact of Perioperative Management for Intracranial Arterial Stenosis on Postoperative Stroke Incidence in Coronary Artery Bypass Surgery

In general, intracranial arterial steno-occlusive lesion (IAS) is known as the most common cause of stroke. Previous studies demonstrated that the prevalence of IAS was equal to or even higher than that of extracranial carotid lesions in patients undergoing coronary artery bypass grafting (CABG) and that its severity was parallel to the number of diseased coronary arteries. A large-scale study showed that total assessment of CVD using magnetic resonance imaging and angiography (MRI/A) was the most useful method to predict perioperative stroke in patients undergoing CABG. Nevertheless, IAS is not routinely evaluated preoperatively in many patients undergoing CABG. In this paper, the authors hypothesized that adequate perioperative management for IAS is useful to prevent stroke in CABG. 

IAS was evaluated using magnetic resonance imaging/angiography (MRI/A, n = 216) in patients without a history of stroke or carotid stenosis (≥50%) in CABG between May 2005 and June 2018 (n = 424). Off-pump CABG was performed in most patients. Different perioperative managements of systolic arterial pressure (SAP) were applied for patients with and without MRI/A. SAP was strictly maintained at ≥80 mmHg in patients with significant IAS (≥50%, n = 28) and ≥90 mmHg for severe IAS (≥70%, n = 44) while SAP less than 80 mmHg (usually ≥70 mmHg) was allowed for patients without MRI/A. Intra-aortic balloon pumping was used for patients with multiple severe IAS and/or occlusion. Clinical outcomes were compared between patients with and without MRI/A. Propensity matching was performed (n = 181 each). 

Complete revascularization was achieved in all patients. Nine patients (2.12%) had postoperative strokes; the incidence of stroke was signifi-cantly less in patients with preoperative MRI/A (n = 1, p = 0.016). There was no significant difference in the incidence of in-hospital mortality between patients with and without preoperative MRI/A (0.5% and 1.0%, respectively; p = 0.529). Multivariate analysis revealed that no preoperative MRI/A was the only significant predictors of postoperative stroke (p = 0.045). The incidence of stroke was not higher in patients with IAS who underwent MRI/A (p = 0.332). 

In summary, in this study, the preoperative evaluation of intracranial atherosclerosis using MRI/A and following our perioperative management for patients with IAS markedly decreased the incidence of perioperative stroke in patients undergoing CABG. Because most strokes occurred in the distal area of IAS, IAS could be a crucial cause of perioperative stroke. Therefore, we recommend preoperative brain MRI/A for patients with high risk of cerebrovascular atherosclerosis in CABG.

Article by Hajime Imura, et al, from Japan.

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