Yasmin Aziz, MD
Morey JR, Zhang X, Fares Marayati N, Matsoukas S, Fiano E, Oxley T, Dangayach N, Stein LK, Fara MG, Skliut M, et al. Mobile Interventional Stroke Teams Improve Outcomes in the Early Time Window for Large Vessel Occlusion Stroke. Stroke. 2021.
In modern medicine, there is only a small subset of physicians who travel with their respective team to spoke locations acutely for intervention. Here, the neurointervention team at Mount Sinai in New York City flipped the table on the traditional drip and ship (DS) model of patient transfer by doing just that.
In this study, the authors assess whether time from last known well (LKW) influences the success of their Mobile Interventional Stroke Teams (MIST) model compared to the traditional DS model. To review, the results of their earlier study, “The NYC MIST Trial,” showed the MIST model to be superior to conventional triage models in terms of faster groin puncture times and patient outcomes.
The authors combined patients from the NYC Mist Trial with another prospectively collected group of patients presenting with large vessel occlusion (LVO) over a three-year time period (January 2017 to February 2020). Patients were then stratified by time to the early window (within 6 hours of LKW) or the late window (>6 hours from LKW). The primary endpoint was 90-day mRS of 2 or less, with secondary endpoints of discharge mRS and NIHSS.
Of the 561 cases reviewed, 226 were eligible part of the DS or MIST triage strategies. When comparing the two models in the late time window, no significant difference was found between the MIST model (35%) verses the DS model (41%), p=0.77. However, in the early time window, 40/74 (54%) patients in the MIST model had a favorable 90-day mRS compared to only 24/86 (28%) of patients in the DS model, p<0.01. Secondary endpoints of discharge mRS and NIHSS were also significantly better for the MIST model in the early time window as well.
This study is limited by its retrospective observational approach, as noted by the authors. While the effect of the MIST model may be explained by capture of the stroke “fast progressors,” the true limitation of the MIST approach is in its feasibility. Even if the results are replicated by larger prospective trials, this particular method will pose significant challenges to the status quo for stroke triage and intervention. Moreover, New York City is, at best, an outlier from the norm when it comes to traffic gridlock and fluid logistics of care, making its relevance as a time-saving intervention in smaller cities questionable. Further research will be needed, much like the story of the mobile stroke EMS units, in order to determine whether the MIST model will be both possible and useful across the country.
Thanks Dr. Kellner for posting this important study. Although the study has limitations, it is helpful to challenge the standard of Stroke care to assess the patient and then tailor care protocols to better treat that presentation than use a one-size-fits all approach. I am curious to hear to what future trials you are planning and see what other technology can help you better assess, stabilize, and recover from ischemic and hemorrhagic stroke. -Pratik