Anaesthetists and doctors, in consultation with their patients, should decide which of general or local anaesthetic is most appropriate for carotid surgery for each individual case – as an Article published Online first and in an upcoming edition of The Lancet shows that there is no definite difference in outcomes using either technique. The study was written by Dr Michael Gough, Department of Vascular Surgery, Leeds General Infirmary, UK, and colleagues from the GALA* collaborative group.
Patients with a blockage or narrowing of their carotid artery (which runs though the neck to the head) are at increased risk of stroke. A surgical procedure called a carotid endarterectomy (CE) is often advised for these patients, especially when they have suffered a transient ischaemic attack (not as serious as a stroke) or a non-disabling ischaemic stroke. During CE, carotid arteries are clamped, the inside of the internal carotid artery is exposed, and the plaque substance causing the blockage is removed. During the operation, the brain’s blood supply can come either from other blood vessels or via an inserted ‘shunt’.
Shunts should protect the brain from stroke that results from low cerebral-blood flow during carotid clamping, they can dislodge the material causing the blockage, causing embolism to the brain. Prior to the trial, it was thought that operations under local anaesthesia may be safer than under general anaesthesia, partly because awake testing of brain function under local anaesthesia during carotid clamping alerts the surgeon to the need for a shunt more reliably than the various indirect techniques used under general anaesthesia. Consequently, fewer shunts are used.
In this randomised controlled trial, done between 1999 and 2007, the researchers analysed 3526 patients from 95 centres in 24 countries. All patients had symptomatic or asymptomatic carotid artery blockage, and were randomly assigned to general anaesthetic (1753 patients) or local anaesthetic (1773 patients). The primary outcome was the proportion of patients with stroke (including retinal blood vessel blockage), heart attack, or death between randomisation and 30 days after surgery. The researchers found a similar incidence of primary events in both groups: 4.8% of patients from the general anaesthetic group, compared with 4.5% in the local anaesthetic group. Nor did the two groups significantly differ for quality of life, length of hospital stay, or in the prespecified subgroups of age, contralateral carotid occlusion**, and baseline surgical risk.
The authors conclude: “In regard to major perioperative complications of stroke, heart attack, and death, there is no reason to prefer general over local anaesthesia, or vice versa, as routine for carotid endarterectomy. Similarly, we showed no definite evidence that the type of anaesthesia affects length of hospital stay or quality of life. Ideally, therefore, surgical and anaesthetic teams should be competent in both techniques because a patient might prefer, or there might be a medical reason to choose one rather than the other.”
In an accompanying Comment, Dr Joanne Guay, University of Montreal and Maisonneuve-Rosemont Hospital, Montreal, Canada, discusses the implications of the GALA trial results, and says: “In the Lancet today, we are finally given the study we have been waiting for on this topic.” She expresses her concerns regarding the final conclusions that can be drawn from the trial since the differences in outcomes are small and not statistically significant. Furthermore she states her uncertainty over whether another larger trial is the way forward or whether the decision regarding use of local or general anaesthetic is best left to the doctor, anaesthetist and patient.
** contralateral carotid occlusion= A complete block of the carotid artery on the opposite side of the neck to the artery being operated on.
“General anaesthesia versus local anaesthesia for carotid surgery (GALA): a multicentre, randomised controlled trial.”
GALA Trial Collaborative Group
The Lancet, Early Online Publication, 27 November 2008 doi:10.1016/S0140-6736(08)61699-2
Click here to view Summary online.
32 Jamestown Road