Prospective, Multicenter, Controlled Trial of Mobile Stroke Units.

BACKGROUND: Mobile stroke units (MSUs) are ambulances with staff and a computed tomographic scanner that may enable faster treatment with tissue plasminogen activator (t-PA) than standard management by emergency medical services (EMS). Whether and how much MSUs alter outcomes has not been extensively studied. METHODS: In an observational, prospective, multicenter, alternating-week trial, we assessed outcomes from MSU or EMS management within 4.5 hours after onset of acute stroke symptoms. The primary outcome was the score on the utility-weighted modified Rankin scale (range, 0 to 1, with higher scores indicating better outcomes according to a patient value system, derived from scores on the modified Rankin scale of 0 to 6, with higher scores indicating more disability). The main analysis involved dichotomized scores on the utility-weighted modified Rankin scale (≥0.91 or <0.91, approximating scores on the modified Rankin scale of ≤1 or >1) at 90 days in patients eligible for t-PA. Analyses were also performed in all enrolled patients. RESULTS: We enrolled 1515 patients, of whom 1047 were eligible to receive t-PA; 617 received care by MSU and 430 by EMS. The median time from onset of stroke to administration of t-PA was 72 minutes in the MSU group and 108 minutes in the EMS group. Of patients eligible for t-PA, 97.1% in the MSU group received t-PA, as compared with 79.5% in the EMS group. The mean score on the utility-weighted modified Rankin scale at 90 days in patients eligible for t-PA was 0.72 in the MSU group and 0.66 in the EMS group (adjusted odds ratio for a score of ≥0.91, 2.43; 95% confidence interval [CI], 1.75 to 3.36; P<0.001). Among the patients eligible for t-PA, 55.0% in the MSU group and 44.4% in the EMS group had a score of 0 or 1 on the modified Rankin scale at 90 days. Among all enrolled patients, the mean score on the utility-weighted modified Rankin scale at discharge was 0.57 in the MSU group and 0.51 in the EMS group (adjusted odds ratio for a score of ≥0.91, 1.82; 95% CI, 1.39 to 2.37; P<0.001). Secondary clinical outcomes generally favored MSUs. Mortality at 90 days was 8.9% in the MSU group and 11.9% in the EMS group. CONCLUSIONS: In patients with acute stroke who were eligible for t-PA, utility-weighted disability outcomes at 90 days were better with MSUs than with EMS. (Funded by the Patient-Centered Outcomes Research Institute; BEST-MSU ClinicalTrials.gov number, NCT02190500.).

High-resolution CT with arch/neck/head CT angiography on a mobile stroke unit.

BACKGROUND: Mobile stroke units (MSUs) performance dependability and diagnostic yield of 16-slice, ultra-fast CT with auto-injection angiography (CTA) of the aortic arch/neck/circle of Willis has not been previously reported. METHODS: We performed a prospective observational study of the first-of-its kind MSU equipped with high resolution, 16-slice CT with multiphasic CTA. Field CT/CTA was performed on all suspected stroke patients regardless of symptom severity or resolution. Performance dependability, efficiency and diagnostic yield over 365 days was quantified. RESULTS: 1031 MSU emergency activations occurred; of these, 629 (61%) were disregarded with unrelated diagnoses, and 402 patients transported: 245 (61%) ischemic or hemorrhagic stroke, 17 (4%) transient ischemic attack, 140 (35%) other neurologic emergencies. Total time from non-contrast CT/CTA start to images ready for viewing was 4.0 (IQR 3.5-4.5) min. Hemorrhagic stroke totaled 24 (10%): aneurysmal subarachnoid hemorrhage 3, hemorrhagic infarct 1, and 20 intraparenchymal hemorrhages (median intracerebral hemorrhage score was 2 (IQR 1-3), 4 (20%) spot sign positive). In 221 patients with ischemic stroke, 73 (33%) received alteplase with 31.5% treated within 60 min of onset. CTA revealed large vessel occlusion in 66 patients (30%) of which 9 (14%) were extracranial; 27 (41%) underwent thrombectomy with onset to puncture time averaging 141±90 min (median 112 (IQR 90-139) min) with full emergency department (ED) bypass. No imaging needed to be repeated for image quality; all patients were triaged correctly with no inter-hospital transfer required. CONCLUSIONS: MSU use of advanced imaging including multiphasic head/neck CTA is feasible, offers high LVO yield and enables full ED bypass.

Resolving Clinical Trial Subject Disengagement in Socioeconomically Disadvantaged Subjects.

BACKGROUND: Clinical trialists may be reluctant to enroll socioeconomically disadvantaged participants because of concerns for subject disengagement leading to noncompliance with longitudinal measures and high lost to follow-up (LTFU) rates. OBJECTIVES: We describe the LTFU problem associated with disadvantaged participants and propose strategies to reduce clinical trial disengagement. METHODS: Difficulties encountered in recruiting and retaining socioeconomically disadvantaged participants along with antecedents of disengagement are discussed. Data in the public domain were used to derive, symbolize, and map engagement by census tract. Exemplars of engaged and disengaged clinical trial participants are shared, and geospatial distribution of socio-spatial disengagement risk is presented. RESULTS: Subject disengagement can be visualized by geospatial informatics suggesting areas of low and high socio-spatial disengagement risk. By failing to enroll socioeconomically disadvantaged subjects, researchers may deliberately exclude those who may benefit the most because of significant health disparities. DISCUSSION: We propose a study of realistic LTFU rates for disadvantaged participants. Realistic clinical trial end points and methods may reduce disengagement among disadvantaged participants.

Geospatial Visualization of Mobile Stroke Unit Dispatches: A Method to Optimize Service Performance.

BACKGROUND: Timely treatment of acute ischemic stroke is crucial to optimize outcomes. Mobile stroke units (MSU) have demonstrated ultrafast treatment compared to standard emergency care. Geospatial analysis of the distribution of MSU cases to optimize service delivery has not been reported. METHODS: We aggregated all first-year MSU dispatch occurrences and all cases classified by clinical teams as true stroke by zip code and calculated dispatch and true stroke incidence rates. We mapped dispatch and stroke cases and symbolized incidence rates by standard deviation. We confirmed visual impressions of clusters from map inspection by local Moran's I, boxplot inspection, and t test. We calculated service areas using drive times to meet dispatch and true stroke need. RESULTS: A significant cluster of high dispatch incident rate was confirmed around our MSU base in urban Memphis within a 5-min driving area supporting the initial placement of the MSU based on 911 activation. A significant cluster of high true stroke rate was confirmed to the east of our MSU base in suburban Memphis within a 10-min driving area. Mean incident longitude of cases of true stroke versus disregarded status was significantly eastward (p = 0.001785). CONCLUSION: Our findings will facilitate determination of socio-spatial antecedents of neighborhood overutilization of 911 and MSU services in our urban neighborhoods and service delivery optimization to reach neighborhoods with true stroke burden.

Geographic access to interventional cardiology services in one rural state.

OBJECTIVES: Explore (1) the characteristics of the Maine population with delayed geographic access to interventional cardiology (IC) services and (2) the effect of delayed geographic IC access on coronary mortality. BACKGROUND: Acute coronary syndrome (ACS), ST-segment elevated myocardial infarction (STEMI), and non-ST segment elevated myocardial infarction (NSTEMI) are highly prevalent. Coronary mortality is minimized when victims have prompt IC access. METHODS: The study design was (1) an exploration of census data to investigate disparities in geographic IC access and (2) a secondary analysis of administrative claims data to investigate coronary mortality relative to delayed geographic IC access. RESULTS: Delayed access was associated in the Maine population with rural residence, advanced age, high school education, and lack of health insurance. Delayed access was associated with increased unadjusted coronary mortality, but not age-adjusted coronary mortality. CONCLUSION: Delayed geographic IC access was associated with disparity but not with increased age-adjusted coronary mortality.

Effectiveness of regionalized systems for stroke and myocardial infarction.

BACKGROUND: Acute ischemic stroke (AIS) and ST-segment elevation myocardial infarction (STEMI) are ischemic emergencies. Guidelines recommend care delivery within formally regionalized systems of care at designated centers, with bypass of nearby centers of lesser or no designation. We review the evidence of the effectiveness of regionalized systems in AIS and STEMI. METHODS: Literature was searched using terms corresponding to designation of AIS and STEMI systems and from 2010 to the present. Inclusion criteria included report of an outcome on any dependent variable mentioned in the rationale for regionalization in the guidelines and an independent variable comparing care to a non- or pre-regionalized system. Designation was defined in the AIS case as certification by the Joint Commission as either a primary (PSC) or comprehensive (CSC) stroke center. In the STEMI case, the search was conducted linking "regionalization" and "myocardial infarction" or citation as a model system by any American Heart Association statement. RESULTS: For AIS, 17 publications met these criteria and were selected for review. In the STEMI case, four publications met these criteria; the search was therefore expanded by relaxing the criteria to include any historical or anecdotal comparison to a pre- or nonregionalized state. The final yield was nine papers from six systems. CONCLUSION: Although regionalized care results in enhanced process and reduced unadjusted rates of disparity in access and adverse outcomes, these differences tend to become nonsignificant when adjusted for delayed presentation and hospital arrival by means other than emergency medical services. The benefits of regionalized care occur along with a temporal trend of improvement due to uptake of quality initiatives and guideline recommendations by all systems regardless of designation. Further research is justified with a randomized registry or cluster randomized design to support or refute recommendations that regionalization should be the standard of care.