Critical analysis of the literature and standards of reporting on stroke after carotid revascularization

Objective: Mechanisms of procedural stroke after carotid endarterectomy (CEA) or carotid artery stenting are surprisingly underresearched. However, understanding the underlying mechanism could (1) assist in balancing the choice for revascularization vs conservative therapy, (2) assist in choosing either open or endovascular techniques, and (3) assist in taking appropriate periprocedural measures to further decrease procedural stroke rate. The purpose of this study was to overview mechanisms of procedural stroke after carotid revascularization and establish reporting standards to facilitate more granular investigation and individual patient data meta-analysis in the future. Methods: A systematic review was conducted according to the PRISMA statement. Results: The limited evidence in the literature was heterogeneous and of low quality. Thus, no formal data meta-analysis could be performed. Procedural stroke was classified as hemorrhagic or ischemic; the latter was subclassified as hemodynamic, embolic (carotid embolic or cardioembolic) or carotid occlusion derived, using a combination of clinical inference and imaging data. Most events occurred in the first 24 hours after the procedure and were related to hypoperfusion (pooled incidence 10.2% [95% confidence interval (CI), 3.0-17.5] vs 13.9% [95% CI, 0.0-60.9] after CEA vs carotid artery stenting events, respectively) or atheroembolism (28.9% [95% CI, 10.9-47.0]) vs 34.3 [95% CI, 0.0-91.5]). After the first 24 hours, hemorrhagic stroke (11.6 [95% CI, 5.7-17.4] vs 9.0 [95% CI, 1.3-16.7]) or thrombotic occlusion (18.4 [95% CI, 0.9-35.8] vs 14.8 [95% CI, 0.0-30.5]) became more likely. Conclusions: Although procedural stroke incidence and etiology may have changed over the last decades owing to technical improvements and improvements in perioperative monitoring and quality control, the lack of literature data limits further statements. To simplify and enhance future reporting, procedural stroke analysis and classification should be documented preemptively in research settings. We propose a standardized form enclosing reporting standards for procedural stroke with a systematic approach to inference of the most likely etiology, for prospective use in registries and randomized controlled trials on carotid revascularization.