Editor's Choice – Cerebral Hyperperfusion Syndrome After Carotid Artery Stenting: A Systematic Review and Meta-analysis

Introduction: Cerebral hyperperfusion syndrome (CHS) is a preventable cause of stroke after carotid endarterectomy (CEA). There are currently no pooled data available on the incidence of CHS after carotid artery stenting (CAS). The aim of this review was to assess the relevance of CHS in the procedural stroke rate following CAS. Method: A systematic search on incidence rates of CHS after CAS was conducted in the MEDLINE, EMBASE, and Cochrane databases in November 2017. A meta-regression analysis was performed on CHS to explain heterogeneity and determine the impact of potential risk factors on observed CHS. The methodological quality of the included studies was assessed using the Cowley criteria. Results: The pooled CHS risk across 33 studies concerning 8731 CAS patients was 4.6% (3.1–6.8%). Stroke occurred in 47% of CHS patients, of which 54% were fatal or disabling. Average time from procedure to symptoms was 12 h (IQR 8–36 h). Impaired cerebrovascular reserve (CVR) was associated with a higher risk of CHS after CAS (RR 5.18; 95% CI 1.0–26.8; p =.049). Symptomatic status was associated with a lower risk of CHS (RR 0.20; 95% CI 0.07–0.59; p =.001). Conclusion: CHS is a serious and frequent complication in patients undergoing carotid angioplasty with stenting, and is most likely to occur in the very early post-procedural period. Future studies are encouraged to investigate the effect of intensive haemodynamic monitoring, including blood pressure control and assessment of cerebral blood flow, on the incidence of stroke caused by CHS after CAS.