A study published in the journal Stroke has added to the evidence supporting the use of local anaesthesia when possible during endovascular treatment of acute ischaemic stroke. The question of improved outcome associated with the use of local anaesthesia has been one increasingly being raised since the release of overwhelmingly positive results in favour of endovascular treatment of acute stroke in five stroke trials around the world.
Alex Abou-Chebl (Baptist Health Louisville, Louisville, USA) and others analysed patients in the Interventional management of stroke III (IMS III) trial which randomised patients within three hours of acute ischaemic stroke onset to intravenous tissue-type plasminogen activator ± endovascular treatment. General anaesthesia use within seven hours of stroke onset was recorded per protocol. Good outcome was defined as 90-day modified Rankin Scale ≤2. A multivariable analysis adjusting for dichotomised National Institutes of Health Stroke Scale (NIHSS; 8–19 versus ≥20), age, and time from onset to groin puncture was performed.
Abou-Chebl et al report that 434 patients were randomised to endovascular treatment, 269 (62%) were treated under local anaesthesia and 147 (33.9%) under general anaesthesia; 18 (4%) were undetermined. The two groups were comparable except for median baseline NIHSS (16 local anaesthesia versus 18 general anaesthesia; p<0.0001).
“The general anaesthesia group was less likely to achieve a good outcome (adjusted relative risk, 0.68; confidence interval, 0.52–0.90; p=0.0056) and had increased in-hospital mortality (adjusted relative risk, 2.84; confidence interval, 1.65–4.91; p=0.0002). Those with medically indicated general anaesthesia had worse outcomes (adjusted relative risk, 0.49; confidence interval, 0.30–0.81; p=0.005) and increased mortality (relative risk, 3.93; confidence interval, 2.18–7.10; p<0.0001) with a trend for higher mortality with routine general anaesthesia. There was no significant difference in the adjusted risks of subarachnoid haemorrhage (p=0.32) or symptomatic intracerebral haemorrhage (p=0.37),” the authors write.
They conclude stating that general anaesthesia was associated with worse neurological outcomes and increased mortality in the endovascular therapy arm. “Relative risk estimates, though not statistically significant, suggest reduced risk for subarachnoid haemorrhage and symptomatic intracerebral haemorrhage under local anaesthesia. Although the reasons for these associations are not clear, these data support the use of local anaesthesia when possible during endovascular therapy,” the authors add.
This study supports the results of a post hoc-analysis of the use of general anaesthesia in the ground breaking MR CLEAN trial (Multicenter randomized clinical trial of endovascular treatment for acute ischemic stroke in the Netherlands) where investigators reported that the subgroup of patients treated without general anaesthesia benefited more from the endovascular treatment than the subgroup treated under general anaesthesia.
In the MR CLEAN post-hoc analysis, of the 233 patients allocated to intra-arterial treatment, 79 were treated under general anaesthesia, and 137 using local anaesthesia. Using the modified Rankin Scale score to assess patient outcome at 90 days, study author Olvert Berkhemer (Academic Medical Center, Amsterdam, the Netherlands) said, “We noticed that patients treated without general anaesthesia have a higher chance of a functional independent lifestyle. They did better after 90 days.” Intra-arterial treatment without general anaesthesia resulted in 38% good outcome, compared to 23% in the under general anaesthesia group.