A recently published review [1] by our Danish colleagues sums up the more recent trials on the subject of anaesthetic technique for endovascular treatments of ischaemic stroke. Previous publications, many of which are based largely on observational or retrospective data, have suggested harm from general anaesthesia (GA) for these procedures, when compared with conscious sedation (CS). In their review in Current Anesthesiology Reports, Rasmussen et al point to the fact that newer randomised data implies equipoise, showing similar outcomes in the CS and GA groups. This is in line with the findings of the AnStroke [11] trial, which we covered some time back in this article.

Interestingly, a recent review and meta-analysis [2] by Campbell et al arrived at a somewhat different finding. After including a broad spectrum of studies, they concluded that GA was associated with worse neurological outcome, when compared with CS. The bulk of their material consisted of the studies from the HERMES collaboration (MR CLEAN, ESCAPE, EXTEND-IA, SWIFT PRIME, REVASCAT, PISTE, and THRACE [3-9]). In these trials patients were randomised to either standard medical treatment or endovascular therapy, and assessed for neurological outcomes. They were thus designed primarily to evaluate the relative effectiveness of two different stroke treatment modalities, rather than the question of sedation vs. general anaesthesia. The choice of either GA or CS was at the discretion of the treating physicians. In other words, patients were not randomised with respect to anaesthetic technique. Regardless of the fact that differences in baseline characteristics and potential confounding factors were corrected for, the lack of randomisation concerning the question at hand is a weakness. The authors also acknowledge this limitation. When isolating the RCTs that randomised on the basis of GA vs CS (SIESTA, ANSTROKE and GOLIATH trials [10-12]), the results are more equivocal. These studies had a much stricter protocol regarding haemodynamic goals and sedation/anaesthesia techniques, which may have had a beneficial effect in the GA groups. In my mind this strengthens their validity when comparing with the HERMES studies. Furthermore, many of the observational studies may be hampered by a degree of selection bias in that the sicker patients a more likely to require GA in order to safely carry out the procedure.

It seems logical to most anaesthetists that choice of anaesthetic technique should be tailored specifically to the individual patient, for endovascular therapies as for any other procedure. Some of our more unstable patients, in whom we might fear potential airway compromise, hypoventilation or unwarranted intra-procedural movement, would in all likelihood be best served with GA. These findings from high-quality randomised prospective studies will hopefully put some of our doubts to rest and make us less reluctant to offer GA to patients in settings where we deem it to be the superior technique. Especially when it can be carried out in a prompt and protocolised manner, so as to safeguard the patient’s physiology and avoid delaying definitive treatment.

References:

1. Rasmussen, L.K., Simonsen, C.Z., Hendén, P.L. et al. Curr Anesthesiol Rep (2018). https://doi.org/10.1007/s40140-018-0277-2
2. Campbell BCV, van Zwam WH, Goyal M, Menon BK, Dippel DWJ, Demchuk AM, et al. Effect of general anaesthesia on functional outcome in patients with anterior circulation ischaemic stroke having endovascular thrombectomy versus standard care: a meta-analysis of individual patient data. Lancet Neurol. 2018;17:47–53
3. Berkhemer, OA, Fransen, PS, Beumer, D et al. A randomized trial of intraarterial treatment for acute ischemic stroke. N Engl J Med. 2015; 372: 11–20
4. Goyal, M, Demchuk, AM, Menon, BK et al. Randomized assessment of rapid endovascular treatment of ischemic stroke. N Engl J Med. 2015; 372: 1019–1030
5. Campbell, BC, Mitchell, PJ, Kleinig, TJ et al. Endovascular therapy for ischemic stroke with perfusion-imaging selection. N Engl J Med. 2015; 372: 1009–101
6. Saver, JL, Goyal, M, Bonafe, A et al. Stent-retriever thrombectomy after intravenous t-PA vs. t-PA alone in stroke. N Engl J Med. 2015; 372: 2285–2295
7. Jovin, TG, Chamorro, A, Cobo, E et al. Thrombectomy within 8 hours after symptom onset in ischemic stroke. N Engl J Med. 2015; 372: 2296–2306
8. Muir, KW, Ford, GA, Messow, CM et al. Endovascular therapy for acute ischaemic stroke: the Pragmatic Ischaemic Stroke Thrombectomy Evaluation (PISTE) randomised, controlled trial. J Neurol Neurosurg Psychiatry. 2017; 88: 38–44
9. Bracard, S, Ducrocq, X, Mas, JL et al. Mechanical thrombectomy after intravenous alteplase versus alteplase alone after stroke (THRACE): a randomised controlled trial. Lancet Neurol. 2016; 15: 1138–1147
10. Schonenberger, S, Uhlmann, L, Hacke, W et al. Effect of conscious sedation vs general anesthesia on early neurological improvement among patients with ischemic stroke undergoing endovascular thrombectomy: a randomized clinical trial. JAMA. 2016; 316: 1986–1996
11. Lowhagen Henden, P, Rentzos, A, Karlsson, JE et al. General anesthesia versus conscious sedation for endovascular treatment of acute ischemic stroke: The AnStroke Trial (anesthesia during stroke). Stroke. 2017; 48: 1601–1607
12. Simonsen CZ, Yoo AJ, Sørensen LH, Juul N, Johnsen SP, Andersen G, et al. Effect of general anesthesia and conscious sedation during endovascular therapy on infarct growth and clinical outcomes in acute ischemic stroke. JAMA Neurol. 2018;75:470–7

On the same subject I also recommend the following two articles:

Rasmussen M, Espelund US, Juul N, Yoo AJ, Sørensen LH, Sørensen KE, et al. The influence of blood pressure management on neurological outcome in endovascular therapy for acute ischaemic stroke. Br J Anaesth. 2018

Rasmussen M, Simonsen CZ, Sørensen LH, Dyrskog S, Rusy DA, Sharma D, et al. Anaesthesia practices for endovascular therapy of acute ischaemic stroke: a Nordic survey. Acta Anaesthesiol Scand. 2017;61(8):885–94