NASHVILLE, TENN. (FRONTLINE MEDICAL NEWS)When acute ischemic stroke patients undergo an emergency endovascular procedure is it best done with general anesthesia or nongeneral anesthesia?

A post hoc analysis of data collected by a Dutch randomized, controlled trial of intra-arterial therapy suggested that nongeneral anesthesia was associated with substantially better patient outcomes, and the findings convinced the Dutch investigators who ran the study to stick with nongeneral anesthesia as their default approach.

In MR CLEAN (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) ( N. Engl. J. Med. 2015;372:11-20 ), 216 acute ischemic stroke patients underwent intra-arterial treatment following randomization. Among these patients, 79 were treated with general anesthesia and 137 with nongeneral anesthesia. The anesthesia choice was made on a case-by-case basis by each participating interventionalist.

The study’s primary endpoint – 90-day status rated as a good function based on a modified Rankin sale score of 0-2 – occurred in 38% of the intra-arterial patients treated with nongeneral anesthesia, 23% of the intra-arterial patients treated with general anesthesia, and 19% among the control patients who received standard treatment without intra-arterial intervention.

“The effect on outcome that we found with intra-arterial treatment in MR CLEAN was not observed in the subgroup of patients treated with general anesthesia,” said Dr. Olvert A. Berkhemer at the International Stroke Conference. The analysis also showed that patients in the general and nongeneral anesthesia subgroups had similar stroke severity as measured by their National Institutes of Health Stroke Scale score, said Dr. Berkhemer, a researcher at the Academic Medical Center in Amsterdam.

But U.S. stroke specialists who heard the report cautioned that unidentified confounders might explain the results, and they also expressed skepticism that the Dutch observations would deter U.S. interventionalists from continuing to use general anesthesia when they perform endovascular procedures.

“The big concern [about this analysis] is that there may have been some things about the general anesthesia patients that they did not account for. I suspect there is a huge bias, that general anesthesia patients were sicker,” said Dr. Bruce Ovbiagele , professor and chief of neurology at the Medical University of South Carolina in Charleston. “At my institution they have used nongeneral anesthesia, but I have been at other places where they usually use general anesthesia; it is variable,” Dr. Ovbiagele added.

Dr. Berkhemer’s analysis also showed that general anesthesia linked with a delayed start to treatment, but without resulting in a significant difference in time to reperfusion. He noted that “sometimes you cannot do the procedure without general anesthesia,” and in MR CLEAN 6 of the 137 intra-arterial patients who started with nongeneral anesthesia eventually received general anesthesia because of discomfort and pain, Dr. Berkhemer said at the conference, sponsored by the American Heart Association.

He speculated that patients who did not receive general anesthesia did better because they did not undergo acute episodes of reduced blood pressure caused by the hypotensive effect of general anesthesia.

The findings reinforced the approach already used in most of the Dutch centers that participated in MR CLEAN, where nongeneral anesthesia is preferred when possible. “In our center we always use nongeneral anesthesia, we are happy with that and we are not going to change,” said Dr. Diederik W.J. Dippel , lead investigator of MR CLEAN and professor of neurology at Erasmus University Medical Center in Rotterdam, The Netherlands. This prejudice against general anesthesia would make it hard to run a trial in The Netherlands that matched the two anesthesia approaches against each other, Dr. Dippel added. On Twitter @mitchelzoler