Stephanie Parker

Benefits of Stroke Treatment Using a Mobile Stroke Unit Compared With Standard Management The BEST-MSU Study Run-In Phase

Background and Purpose— Faster treatment with intravenous tissue-type plasminogen activator (tPA) is likely to improve outcomes. Optimizing prehospital triage by mobile stroke units (MSUs) may speed treatment times. The Benefits of Stroke Treatment Delivered Using a Mobile Stroke Unit (BEST-MSU) study was launched in May 2014 using the first MSU in the United States to compare stroke management using an MSU versus standard management (SM). Herein, we describe the results of the prespecified, nonrandomized run-in phase designed to obtain preliminary data on study logistics. Methods— The run-in phase consisted of 8 MSU weeks when all-patient care occurred on the MSU and 2 SM weeks when the MSU nurse met personnel on scene or at the emergency department to ensure comparability with MSU patients. Telemedicine was independently performed in 9 MSU cases. Results— Of 130 alerts, 24 MSU and 2 SM patients were enrolled. Twelve of 24 MSU patients received tPA on board; 4 were treated within 60 minutes of last seen normal, and 4 went on to endovascular treatment. There were no hemorrhagic complications. Four had primary intracerebral hemorrhage. Agreement on tPA eligibility between the onsite and telemedicine physician was 90%. Conclusions— The run-in phase provided a tPA treatment rate of 1.5 patients per week, assured us that treatment within 60 minutes of onset is possible, and enabled enrollment of patients on SM weeks. We also recognized the opportunity to assess the effect of the MSU on endovascular treatment and intracerebral hemorrhage. Challenges include the need to control biased patient selection on MSU versus SM weeks and establish inter-rater agreement for tPA treatment using telemedicine.

Establishing the First Mobile Stroke Unit in the United States

Background and Purpose— Recently, the Mobile Stroke Unit (MSU) concept was introduced in Germany demonstrating prehospital treatment of more patients within the first hour of symptom onset. However, the details and complexities of establishing such a program in the United States are unknown. We describe the steps involved in setting up the first MSU in the United States. Methods— Implementation included establishing leadership, fund-raising, purchase and build-out, knitting a collaborative consortium of community stakeholders, writing protocols to ensure accountability, radiation safety, purchasing supplies, licensing, insurance, establishing a base station, developing a communication plan with city Emergency Medical Services, Emergency Medical Service training, staffing, and designing a research protocol. Results— The MSU was introduced after ≈1 year of preparation. Major obstacles to establishing the MSU were primarily obtaining funding, licensure, documenting radiation safety protocols, and establishing a smooth communication system with Emergency Medical Services. During an 8 week run-in phase, ≈2 patients were treated with recombinant tissue-type plasminogen activator per week, one-third within 60 minutes of symptom onset, with no complications. A randomized study to determine clinical outcomes, telemedicine reliability and accuracy, and cost effectiveness was formulated and has begun. Conclusion— The first MSU in the United States has been introduced in Houston, TX. The steps needed to accomplish this are described.

Implementing a Mobile Stroke Unit Program in the United States: Why, How, and How Much?

IMPORTANCE There are many ways a mobile stroke unit (MSU) might prove valuable for patients with ischemic and hemorrhagic stroke, such as earlier recognition, more accurate triage, improved management of blood pressure and other critical physiological variables, and eventually earlier implementation of effective therapies. The MSU may be particularly valuable for treatment of patients with acute ischemic stroke with tissue plasminogen activator (tPA) within 4.5 hours of symptom onset, the most evidence-based effective emergency treatment for the most prevalent stroke diagnosis. OBJECTIVES To review existing data on prehospital stroke treatment, especially relevant to MSU technology, to identify gaps in our understanding of MSU feasibility, especially relevant to applying the MSU strategy in the United States, and to describe the Houston MSU program and clinical trial. EVIDENCE REVIEW Published data from English-language journals in PubMed from 1995 to present reviewing early treatment with tPA and prehospital stroke evaluation and treatment. FINDINGS The MSU may result in an overall shift toward earlier evaluation and treatment with tPA, particularly into the first hour after symptom onset, leading to substantially better outcomes. As a result of improved clinical outcomes owing to earlier treatment, the costs of an MSU program may be offset by a reduction in the costs of long-term stroke care and an increase in quality-adjusted life-years, thereby supporting more widespread use of this technology. To make MSU deployment more practical, the vascular neurologist aboard the MSU must be replaced by a remote vascular neurologist connected to the MSU by telemedicine, reducing manpower requirements and costs. CONCLUSIONS AND RELEVANCE The MSU strategy could dramatically transform the way acute stroke is managed in the United States. A prospective study evaluating the logistics, outcomes, and cost-effectiveness of this approach is needed and under way.

Thrombelastography Detects Possible Coagulation Disturbance in Patients With Intracerebral Hemorrhage With Hematoma Enlargement

Background and Purpose— Intracerebral hemorrhage (ICH) has high morbidity, and hematoma enlargement (HE) causes worse outcome. Thrombelastography (TEG) measures the dynamics of clot formation and dissolution, and might be useful for assessing bleeding risk. We used TEG to detect changes in clotting in patients with and without HE after ICH. Methods— This prospective study included 64 patients with spontaneous ICH admitted from 2009 to 2013. TEG was performed within 6 hours of symptom onset and after 36 hours. Brain imaging was obtained at baseline and at 36±12 hours, and HE was defined as total volume increase >6 cc or >33%. TEG was also obtained from 57 controls. Results— Compared with controls, patients with ICH demonstrated faster and stronger clot formation; shorter R and delta (P<0.0001) at baseline; and higher MA and G (P<0.0001) at 36 hours; 11 patients had HE. After controlling for potential confounders, baseline K and delta were longer in HE+ compared with HE− patients, indicating that HE+ patients had slower clot formation (P<0.05). TEG was not different between HE+ and HE− patients at 36 hours. Conclusions— TEG may detect important coagulation changes in patients with ICH. Clotting may be faster and stronger in immediate response to ICH, and a less robust response may be associated with HE. These findings deserve further investigation.

Telemedicine Can Replace the Neurologist on a Mobile Stroke Unit.

Background and Purpose— The BEST-MSU study (Benefits of Stroke Treatment Delivered Using a Mobile Stroke Unit) is a comparative effectiveness trial in patients randomized to mobile stroke unit or standard management. A substudy tested interrater agreement for tissue-type plasminogen activator eligibility between a telemedicine vascular neurologist and onboard vascular neurologist. Methods— On scene, both the telemedicine vascular neurologist and onboard vascular neurologist independently evaluated the patient, documenting their tissue-type plasminogen activator treatment decision, National Institutes of Health Stroke Scale score, and computed tomographic interpretation. Agreement was determined using Cohen &kgr; statistic. Telemedicine-related technical failures that impeded remote assessment were recorded. Results— Simultaneous and independent telemedicine vascular neurologist and onboard vascular neurologist assessment was attempted in 174 patients. In 4 patients (2%), the telemedicine vascular neurologist could not make a decision because of technical problems. The telemedicine vascular neurologist agreed with the onboard vascular neurologist on 88% of evaluations (&kgr;=0.73). Conclusions— Remote telemedicine vascular neurologist assessment is reliable and accurate, supporting either telemedicine vascular neurologist or onboard vascular neurologist assessment on our mobile stroke unit. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT02190500.

Benefits of stroke treatment delivered using a mobile stroke unit trial

Rationale Mobile stroke units speed treatment for acute ischemic stroke, thereby possibly improving outcomes. Aim To compare mobile stroke unit and standard management clinical outcomes, healthcare utilization, and cost-effectiveness in tissue plasminogen activator-eligible acute ischemic stroke patients calling 911. Sample size 693. Eighty percent power with 0.05 type I error rate to detect a difference of 0.09 in mean utility-weighted modified Rankin scale between groups. Design Phase III, multicenter, prospective cluster-randomized (mobile stroke unit versus standard management weeks) comparative effectiveness study in tissue plasminogen activator-eligible patients. Outcomes Primary: Ninety-day mean utility-weighted modified Rankin scale. Coprimary: cost-effectiveness based on EQ5D quality of life and one year poststroke costs. Analysis Two-sample t-test and linear regression adjusting for covariates; incremental cost-effectiveness ratio and net benefit regression. Results As of March 2017, 288 tissue plasminogen activator-eligible patients have been enrolled (173 in the mobile stroke unit arm and 115 in the standard management arm). Two new centers start in early 2017 with target end of recruitment September 2019. Conclusion This is the first randomized study to test for disability, healthcare utilization, and cost-effectiveness of a mobile stroke unit. The progress of the study suggests that it is feasible. Management of tissue plasminogen activator eligible acute ischemic stroke patients by a mobile stroke unit could potentially result in less disability and healthcare utilization, and be cost effective. Mobile stroke units are very costly. This trial may determine if the fixed cost can be justified by a reduction in disability and healthcare utilization. Clinical Trial Registration NCT02190500.

Radiation Monitoring Results from the First Year of Operation of a Unique Ambulance-based Computed Tomography Unit for the Improved Diagnosis and Treatment of Stroke Patients.

AbstractWhen a blood clot blocks the blood supply to the brain or when a blood vessel bursts, resulting in brain cell death, the medical condition is referred to as a “stroke.” Stroke is a main cause of death worldwide and is a common cause of disability. A common form of stroke, called ischemic stroke, is when blood flow to the brain is decreased. Clinical research has revealed that treatment within the very first hours of symptom onset is key for ischemic stroke with recanalization of occluded arteries by thrombolysis with alteplase. Computed tomography (CT) is one of the diagnostic tools used to determine if this treatment path is appropriate. To determine if health outcomes of possible stroke patients can be improved by decreasing the time from symptom presentation to treatment, the first mobile stroke ambulance unit in the United States was deployed by The University of Texas Health Science Center at Houston (UTHealth) in 2014, equipped with a computed tomography imaging system. The mobile stroke unit shortens the time to treatment for stroke patients by allowing pre-hospital treatment. Having completed its first year of operation, radiation-monitoring data describing the doses delivered to various entities have been characterized. The CT operator’s cumulative deep dose equivalent for 1 y of operation was 1.14 mSv resulting from the care of 106 patients. Area monitors were deployed and measurements performed demonstrating that general public doses did not exceed 0.02 mSv h−1 or 1.0 mSv year.

Iodinated Contrast Does Not Alter Clotting Dynamics in Acute Ischemic Stroke as Measured by Thromboelastography

Background and Purpose— Iodinated contrast agents used for computed tomography angiography (CTA) may alter fibrin fiber characteristics and decrease fibrinolysis by tissue plasminogen activator (tPA). Thromboelastography (TEG) measures the dynamics of coagulation and correlates with thrombolysis in acute ischemic stroke patients. We hypothesized that receiving CTA before tPA will not impair thrombolysis as measured by TEG. Methods— Acute ischemic stroke patients receiving 0.9 mg/kg tPA <4.5 hours of symptom onset were prospectively enrolled. For CTA, 350 mg/dL of iohexol or 320 mg/dL of iodixanol at a dose of 2.2 mL/kg was administered. TEG was measured before tPA and 10 minutes after tPA bolus. CTA timing was left to the discretion of the treating physician. Results— Of 136 acute ischemic stroke patients who received tPA, 47 had CTA before tPA bolus, and 42 had either CTA after tPA and post–tPA TEG draw or no CTA (noncontrast group). Median change in clot lysis (LY30) after tPA was 95.3% in the contrast group versus 95.0% in the noncontrast group (P=0.74). Thus, tPA-induced thrombolysis did not differ between contrast and noncontrast groups. Additionally, there was no effect of contrast on any pre–tPA TEG value. Conclusions— Our data do not support an effect of iodinated contrast agents on clot formation or tPA activity.

Time to Decision and Treatment With tPA (Tissue-Type Plasminogen Activator) Using Telemedicine Versus an Onboard Neurologist on a Mobile Stroke Unit

Background and Purpose— Mobile stroke units (MSUs) can speed treatment with intravenous tPA (tissue-type plasminogen activator). We previously showed substantial agreement between a telemedicine-based vascular neurologist (TM-VN) and an onboard vascular neurologist (OB-VN) for the evaluation of patients with stroke for tPA eligibility on an MSU. However, the time efficiency of the telemedicine-based evaluation remained uncertain. In this study, we examined the speed of decision and treatment from MSU arrival for the TM-VN compared with an OB-VN. Methods— In 50 consecutive situations, the TM-VN served as the primary decision maker. Times from MSU arrival to tPA decision and tPA bolus were compared with the same metrics for when the OB-VN served as the primary decision maker. Results— Time to tPA decision for the TM-VN was 21 minutes (interquartile range, 16.25–26) versus 18 minutes (interquartile range, 14–22) for the OB-VN (P=0.01). Initiation of tPA bolus was 24 minutes (interquartile range, 19.75–30) for the TM-VN versus 24 minutes (interquartile range, 19–27.75) for the OB-VN (P=0.5). Conclusions— Assessment by a TM-VN is comparable with an OB-VN in making decisions about tPA administration on an MSU and does not lead to treatment delays. Clinical Trial Registration— URL: https://www.clinicaltrials.gov. Unique identifier: NCT02190500.

Intraosseous Administration of Tissue Plasminogen Activator on a Mobile Stroke Unit

Abstract Objective: Mobile stroke units offer improved time to administration of thrombolytics for ischemic stroke patients. Acquisition of intravenous (IV) access, however, can be challenging in the prehospital environment leading to treatment delays. Intraosseous (IO) access is commonly used in the prehospital setting for a variety of conditions and may serve as a viable means for tPA (tissue plasminogen activator) administration. Methods/Results: We describe 3 cases in which tPA was administered via IO access on a mobile stroke unit as part of the Benefits of Stroke Treatment Delivered Using a Mobile Stroke Unit Compared to Standard Management by Emergency Medical Services (BEST-MSU) trial. Conclusion: No adverse events were observed in the process of obtaining IO access or administering tPA.