Conscious Sedation Same as Anesthetic for Stroke Thrombectomy

May 19, 2016

BARCELONA — For patients with acute ischemic stroke undergoing endovascular therapy, outcomes at 24 hours did not differ in those having the procedure under conscious sedation or general anesthesia in the SIESTA trial.

Short-term results from the trial, which is the first randomized study to compare conscious sedation vs general anesthesia in the endovascular setting in stroke, were presented by Julian Bosel, MD, University Hospital Heidelberg, Germany, at the recent European Stroke Organisation Conference (ESOC) 2016.

"We did not see a difference in the primary outcome of change in NIHSS [National Institutes of Health Stroke Severity] score at 24 hours between patients receiving general anesthesia and those given conscious sedation," he concluded. "However, this data is preliminary and we don't yet have the main secondary outcome of modified Rankin scores at 3 months. These will be reported at the World Stroke Congress in October."

Start With Conscious Sedation

Professor Bosel recommended that "with strict adherence to protocols, endovascular stroke care can be started safely under conscious sedation and that only a few patients will have to be converted to general anesthesia, but if this becomes necessary it does not seem to be deleterious."

He added: "Of course, some patients will need general anesthesia from the start, such as those who are so agitated that groin puncture is not possible."

Commenting on the study in an ESOC video interview with Professor Bosel, Heinrich Mattle, MD, University of Bern, Switzerland, said, "You have made a clear point on how to manage endovascular treatment from an anesthesiology point of view. This trial should change the practice of medicine."

Professor Bosel explained that most interventionalists prefer using general anesthesia for endovascular treatment in patients with acute ischemic stroke to avoid agitation and pain and to reduce perforations and possibly achieve better recanalization. But whether general anesthesia affects outcomes has never been tested in a randomized trial.

He noted that in the recent milestone trials of endovascular therapy, general anesthesia was not used that much — less than 40% in all the trials, and in two of the trials less than 10% of patients had general anesthesia.

Although data from some of these trials suggested that general anesthesia was associated with a worse outcome, it is difficult to know for sure because patients were not randomly assigned on this question. The analyses were retrospective, so baselines factors were unbalanced and there may been selection bias, he said.

"So we decided to conduct a randomized trial — SIESTA — which compared conscious sedation without intubation vs general anesthesia with intubation in an unselected patient group with acute ischemic stroke undergoing thrombectomy."

Patients could be enrolled into the trial if they had an anterior stroke with an NIHSS score of more than 10 and had been selected for thrombectomy. Exclusion criteria included severe agitation, coma, or vomiting.

The trial randomly assigned 150 patients over 22 months. Professor Bosel said the patients recruited were "a pretty typical endovascular stroke population," with a median NIHSS score of 17. Of the 77 patients starting out with conscious sedation, 11 crossed over to general anesthesia during the procedure. One protocol deviation and no loss to follow-up occurred.

Results showed no difference in the primary endpoint, change in NIHSS scores from baseline to 24 hours. "This was almost identical in the two groups. And there was no difference in subgroups," Professor Bosel reported.

In-hospital mortality was also almost identical, with most deaths due to large strokes.

Some Differences in Secondary Outcomes

Most secondary outcomes were similar, although a few did show differences. These included the sedation group having the endovascular procedure started slightly earlier (about 10 minutes) and the general anesthetic group having slightly better recanalization rates.

There were also more substantial patient movements, as would be expected in the sedation group, and more postintervention complications in the anesthesia group, which were mostly related to ventilation (ie, ventilation-associated pneumonia). "But these are very small signals," Professor Bosel said.

"We were surprised by the results as we expected conscious sedation to be superior as this is what has been suggested by retrospective studies," he commented. "But it is probable that those retrospective studies had some selection bias as sicker patients are more likely to be intubated. They would have tried to correct for this of course but it probably still played a role."

He noted that the study had a strict protocol for both groups with physiologic targets for blood pressure, and CO2 and oxygen saturation levels. "We had quite an elaborate procedure for systemic and cerebral monitoring. The results of these tests are still in the process of being analyzed."

Interestingly, anesthesia was not delivered by anesthesiologists in this study but by neurointensivists. "Anesthesiologists attending these endovascular patients need a good understanding of cerebral pathology of stroke. It is important for the anesthetic to be given by someone with a special interest in neural anesthesia," he said.

Yvo Roos, MD, Academic Medical Center, Amsterdam, Netherlands, headed up the MR CLEAN trial, the subgroup analysis of which suggested a superior result with conscious sedation rather than general anesthesia. Commenting for Medscape Medical News, he said he still believes conscious sedation is better.

"We have only seen early outcome data from the SIESTA trial so far," he said. "I am still convinced there will be a disadvantage of general anesthesia by 3 months because of the effect we have seen in practice."

He elaborated: "When we were running MR CLEAN we always used general anesthesia in our hospital but after we saw the results from all centers we realized that those who did not use general anaesthesia were having much better results. We have now totally moved over to not using general anaesthesia.

"The difference is enormous," he added. "Now we are disappointed when a patient doesn't recover completely. It is quite clear to everyone that there has been improvement since we stopped using general anesthesia. I am convinced it is true and the 3 month data from SIESTA will show this."

European Stroke Organisation Conference (ESOC) 2016. Presented May 10, 2016.

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