Meta-analysis and trial sequential analysis of local vs. general anaesthesia for carotid endarterectomy

Abstract

Controversy exists regarding the best choice of anaesthesia for carotid endarterectomy. We aimed to evaluate the peri-operative outcomes of local vs. general anaesthesia for carotid endarterectomy. We conducted a systematic search of electronic information sources and applied a combination of free text and controlled vocabulary searches adapted to thesaurus headings, search operators and limits in each of the electronic databases. We defined peri-operative stroke, transient ischaemic attack, mortality and myocardial infarction as the primary outcome measures. We identified 12 randomised controlled trials and 21 observational studies reporting a total of 58,212 patients undergoing carotid endarterectomy under local or general anaesthesia. Analysis of observational studies demonstrated that local anaesthesia was associated with a significantly lower incidence of stroke (odds ratio (OR (95% CI) 0.66 (0.55–0.80), p < 0.0001), transient ischaemic attack (0.52 (0.38–0.70), p < 0.0001), myocardial infarction (0.55 (0.41–0.75), p = 0.0002) and mortality (0.72 (0.56–0.94), p = 0.01) compared with general anaesthesia. Analysis of randomised controlled trials did not find a significant difference in the risk of stroke (0.92 (0.67–1.28), p = 0.63), transient ischaemic attack (2.20 (0.48–10.03), p = 0.31), myocardial infarction (1.25 (0.57–2.72), p = 0.58) or mortality (0.61 (0.35–1.05), p = 0.07) between local and general anaesthesia. On trial sequential analysis of the randomised trials, the Z-curve did not cross the α-spending boundaries or futility boundaries for stroke, mortality and transient ischaemic attack, suggesting that more trials are needed to reach conclusive results. Our meta-analysis of observational studies suggests that local anaesthesia for carotid endarterectomy may be associated with lower peri-operative morbidity and mortality compared with general anaesthesia. Although randomised studies have not confirmed any advantage for local anaesthesia, this may be due to a lack of pooled statistical power in these trials.