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LOS ANGELES -- Mobile stroke units not only sped stroke treatment but improved outcomes for ischemic stroke, a trial from early-adopter Berlin showed.

Modified Rankin Scale (mRS) score at 90 days shifted significantly toward functionally independent survival in patients with ischemic stroke for whom a mobile unit with CT scan and prehospital thrombolysis capability was available, compared with those for whom one was not available (OR 0.74 for functional disability, 95% CI 0.60-0.90).

Results were similar after excluding patients showing no neurological deficits when the ambulance arrived, Heinrich Audebert, MD, of Charité Berlin, reported here at the International Stroke Conference (ISC).

A coprimary outcome categorizing patients more broadly into three categories -- an mRS of 3 or better or living at home, 4-5 or living in an institution, or dead -- to capture outcomes of those lost to follow-up yielded a similar odds ratio favoring mobile stroke units but which narrowly missed statistical significance (0.75 for disability, 95% CI 0.56-1.01).

Among the secondary outcomes, symptomatic hemorrhage was not increased with mobile stroke unit availability but the odds were better for an mRS better than 2 in those 80 and younger or better than 3 in those over 80 (52% vs 45%, P=0.004), and quality of life was improved as well.

The mechanism appeared to be driven by early thrombolysis, with 21% more thrombolyzed within an hour with mobile stroke unit available versus 8% when it was not; rates of thrombolysis initiated later were similar between groups at 38%-39%. Overall, thrombolytic treatment was 60% with mobile unit availability vs 48% without (P<0.01).

Time from alarm to start of thrombectomy in Audebert's study wasn't significantly different with the mobile stroke unit (137 vs 125 minutes).

Regardless, "just waiting until patients arrive at the hospital is not enough anymore," concluded Audebert.

"We know we can treat patients with thrombolysis sooner; this was the first time they've shown a modified Rankin effect, that there's actually a clinical benefit," commented Louise McCullough, MD, PhD, of the University of Texas Health Science Center at Houston, who was a moderator at the ISC late-breaking session.

These findings likely presage a wave of similar comparisons from other regions that followed the German example in organizing these systems for mobile stroke unit dispatch, McCullough predicted.

"The Germans have been doing this for awhile," commented Mariell Jessup, MD, the American Heart Association's chief medical officer. "There's a lot of excitement for that, especially in rural areas."

In Berlin, the first mobile stroke unit started operation in February 2017, with a second coming later in the year and a third in September 2018. Operating hours were 7 a.m. to 11 p.m.

In total, 14,519 cases triggered a mobile stroke unit alarm; in about half, the unit was not available to respond. Among those cerebral ischemia patients with ambulance transport, with a stroke code at the dispatch level, and not deemed hemorrhagic stroke, 842 fulfilled these inclusion criteria when the mobile stroke unit wasn't available and 795 when it was available.

Demographics were fairly similar between those groups, but in 26% of cases when the mobile stroke unit was available, patients were not actually treated by the unit. In some cases, symptoms fluctuated and thrombolysis was actually administered at the hospital instead of in the unit, Audebert said.

However, he acknowledged that the mobile stroke unit may also have contributed to better outcomes through early neurological assessment, continuous monitoring, and early complication management.

Limitations included the restriction to a single metropolitan area in Germany, so generalizability was unknown. Also, the high number of dispatches of the mobile stroke unit for patients who were not treatment candidates suggested a need to improve the quality of dispatch mobilization, Audebert noted.

With further results expected in the next couple years from the U.S., "once we start getting this data, they will be able to further refine these mobile stroke units and what type of city, how to manage them," McCullough noted, as well whether it has an effect on endovascular therapy for large vessel occlusions.

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