Better Outcomes With Local Anesthesia for Stroke Treatments

9th World Stroke Congress (WSC). Abstract 032. Presented October 23, 2014.

Authors: Daniel M. Keller, PhD

For patients undergoing an endovascular procedure to treat acute stroke, local anesthesia (LA) was associated with better clinical outcomes and no higher rate of complications compared with general anesthesia (GA), a retrospective analysis of a pretrial cohort of the MR CLEAN trial shows.

MR CLEAN (Multicenter Randomized Clinical trial of Endovascular treatment for Acute ischemic stroke in the Netherlands) was a trial involving adult patients with acute ischemic stroke of the anterior circulation.

In the main part of the trial an intervention group received intra-arterial therapy (IAT) using a microcatheter to deliver mechanical treatment or a thrombolytic agent, or both, at the level of the occlusion. Mechanical treatment could be a retrievable stent, thrombus retraction, aspiration, or wire manipulation.

In a poster presentation here at the 9th World Stroke Congress (WSC), Luci van den Berg, MD, and a PhD candidate in the Neurovascular Research Group at the Academic Medical Center of the University of Amsterdam, the Netherlands, reported on a pretrial cohort of 369 patients (n = 348 in the final analysis) with acute ischemic stroke of the anterior circulation treated with IAT in 16 Dutch hospitals between 2005 and 2013 to compare outcomes based on local vs general anesthesia.

“The data from this consecutive cohort was gathered in order to assess pretrial experience in centers that would start including patients in the MR CLEAN trial,” she said. “Information concerning procedures and treated patients was registered in a database in preparation for participation in the MR CLEAN trial.”

It was worth comparing the routes and levels of anesthesia because several factors could potentially affect outcomes, including intubation, blood pressure shifts, and treatment delays associated with GA. On the other hand, LA at the site of device insertion may allow patient movement during procedures, possibly leading to complications. Previous studies had methodologic limitations, so no definitive conclusions could be drawn from them.

The LA (n = 278) and GA (n = 70) groups were well balanced for sex (about half male) and for National Institutes of Health Stroke Scale scores (15 vs 16, respectively). However, the LA group was older (62 vs 57 years; P = .03), had more cases with atrial fibrillation (29.3% vs 16.4%; P = .03), had a shorter time from symptom onset to IAT (220 vs 241 minutes; P = .02), and had less mechanical thrombectomy (70.9% vs 87.1%; P = .005).

After correcting for age and stroke severity, the researchers found that LA for the endovascular procedure was associated with better clinical outcomes, as assessed on the modified Rankin Scale (mRS); about 26% of LA patients had a good clinical outcome (mRS score, 0 to 2) compared with about 14% of GA patients (P = .04).

Table. Functional Outcomes at Discharge
mRS Score                           LA Group (%)                              GA Group (%)
0                                                   4.7                                                     2.9
1                                                    6.9                                                    4.3
2                                                   14.5                                                   7.1
3                                                   19.2                                                   15.7
4                                                   25.7                                                   37.1
5                                                   12.3                                                    11.4
6                                                   16.7                                                    21.4

With LA, there was a trend toward more patients being treated within the first 3 hours (27.7%) compared with the group receiving GA (17.1%; P = .07), as well as a trend toward more patients achieving full recanalization (41.5% vs 30%, respectively; P = .08).

The intraprocedural or postprocedural complication rates did not significantly differ between the anesthesia methods. Ten percent of LA patients were converted to GA. Approximately 11% to 12% of patients in both groups experienced symptomatic intracranial hemorrhage.

Randomized Trial

Didier Leys, MD, PhD, professor of neurology at the University of Lille, France found the results quite interesting in that LA patients had a better outcome than patients treated with GA.

“We can see that the effects [for each treatment] are almost the same [across] the whole range of Rankin scale,” he said. The results are “something we have to bear in mind.”

He noted that problems with the presentation are that it did not detail the methods and that the study was retrospective and probably not randomized, so it does not eliminate the possibility of patient selection bias; therefore, “we cannot prove with this that local anesthesia is better.”

However, as Dr van den Berg pointed out, this study was derived from a pretrial cohort to assess the performance of centers participating in the main MR CLEAN trial.

Nonetheless, Dr Leys suggested that the findings could be the underpinnings to conduct a formal randomized trial of the two kinds of anesthesia, which could be useful. “There is a rationale for that, which is that we can go quicker for local anesthesia, and if we treat the patients 15 minutes earlier, the effect is probably better,” he said.

If it would turn out that LA is better, Dr Leys speculated that the reasons could be faster times to interventions and avoiding a possibly small reduction in blood pressure with GA. No one is really sure of the effect of GA in acute ischemic stroke, he noted.

At his center, he said clinicians use GA exclusively, “but maybe we’ll have to change. We don’t know.”