Effect of the use of ambulance-based thrombolysis on time to thrombolysis in acute ischemic stroke: a randomized clinical trial

Comparison of the university hospital and county hospitals in western Sweden to identify potential weak links in the early chain of care for acute stroke: results of an observational study

OBJECTIVE

To identify weak links in the early chain of care for acute stroke.

SETTING

9 emergency hospitals in western Sweden, each with a stroke unit, and the emergency medical services (EMS).

PARTICIPANTS

All patients hospitalised with a first and a final diagnosis of stroke-between 15 December 2010 and 15 April 2011. The university hospital in the city of Gothenburg was compared with 6 county hospitals. PRIMARY AND SECONDARY MEASURES: (1) The system delay, that is, median delay time from call to the EMS until diagnosis was designated as the primary end point. Secondary end points were: (2) the system delay time from call to the EMS until arrival in a hospital ward, (3) the use of the EMS, (4) priority at the dispatch centre and (5) suspicion of stroke by the EMS nurse.

RESULTS

In all, 1376 acute patients with stroke (median age 79 years; 49% women) were included. The median system delay from call to the EMS until (1) diagnosis (CT scan) and (2) arrival in a hospital ward was 3 h and 52 min and 4 h and 22 min, respectively. The system delay (1) was significantly shorter in county hospitals. (3) The study showed that 76% used the EMS (Gothenburg 71%; the county 79%; p<0.0001). (4) Priority 1 was given at the dispatch centre in 54% of cases. (5) Stroke was suspected in 65% of cases. A prenotification was sent in 32% (Gothenburg 52%; the county 20%; p<0.0001).

CONCLUSIONS

System delay is still long and only a small fraction of patients received thrombolysis. Three of four used the EMS (more frequent in the county). They were given the highest priority at the dispatch centre in half of the cases. Stroke was suspected in two-thirds of the cases, but a prenotification was seldom sent to the hospital.

Point of care coagulometry in prehospital emergency care: an observational study

Background

Haemostatic impairment can have a crucial impact on the outcome of emergency patients, especially in cases of concomitant antithrombotic drug treatment. In this prospective observational study we used a point of care (POC) coagulometer in a prehospital physician-based emergency medical system in order to test its validity and potential value in the treatment of emergency patients.

Methods

During a study period of 12 months, patients could be included if venous access was mandatory for further treatment. The POC device CoaguChek® was used to assess international normalized ratio (INR) after ambulance arrival at the scene. Results were compared with in-hospital central laboratory assessment of INR. The gain of time was analysed as well as the potential value of POC testing through a questionnaire completed by the responsible prehospital emergency physician.

Results

A total of 103 patients were included in this study. POC INR results were highly correlated with results of conventional assessment of INR (Bland-Altman-bias: 0.014). Using a cutoff value of INR >1.3, the device’s sensitivity to detect coagulopathy was 100 % with a specificity of 98.7 %. The median gain of time was 69 min. Treating emergency physicians considered the value of prehospital POC INR testing ‘high’ in 9 % and ‘medium’ in 21 % of all patients. In patients with tracer diagnosis ‘neurology’, the value of prehospital INR assessment was considered ‘high’ or ‘medium’ (63 %) significantly more often than in patients with non-neurological tracer diagnoses (24 %).

Conclusions

Assessment of INR through a POC coagulometer is feasible in prehospital emergency care and provides valuable information on haemostatic parameters in patients. Questionnaire results suggest that POC INR testing may present a valuable technique in selected patients. Whether this information translates into an improved management of respective patients has to be evaluated in further studies.

Copeptin Levels in Patients With Acute Ischemic Stroke and Stroke Mimics

BACKGROUND AND PURPOSE

Copeptin levels are increased in patients diagnosed with stroke and other vascular diseases. Copeptin elevation is associated with adverse outcome, predicts re-events in patients with transient ischemic attack and is used in ruling-out acute myocardial infarction. We evaluated whether copeptin can also be used as a diagnostic marker in the prehospital stroke setting.

METHODS

We prospectively examined patients with suspected stroke on the Stroke Emergency Mobile-an ambulance that is equipped with computed tomography and point-of-care laboratory. A blood sample was taken from patients immediately after arrival. We analyzed copeptin levels in patients with final hospital-based diagnosis of stroke or stroke mimics as well as in vascular or nonvascular patients. In addition, we examined the associations of symptom onset with copeptin levels and the prognostic value of copeptin in patients with stroke.

RESULTS

Blood samples of 561 patients were analyzed. No significant differences were seen neither between cerebrovascular (n=383) and other neurological (stroke mimic; n=90) patients (P=0.15) nor between vascular (n=391) and nonvascular patients (n=170; P=0.57). We could not detect a relationship between copeptin levels and time from onset to blood draw. Three-month survival status was available in 159 patients with ischemic stroke. Copeptin levels in nonsurviving patients (n=8: median [interquartile range], 27.4 [20.2-54.7] pmol/L) were significantly higher than in surviving patients (n=151: median [interquartile range], 11.7 [5.2-30.9] pmol/L; P=0.024).

CONCLUSIONS

In the prehospital setting, copeptin is neither appropriate to discriminate between stroke and stroke mimic patients nor between vascular and nonvascular patients.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01382862. The Pre-Hospital Acute Neurological Therapy and Optimization of Medical Care in Stroke Patients study (PHANTOM-S) was registered (NCT01382862). This sub-study was observational and not registered separately, therefore.

Imaging of prehospital stroke therapeutics

Despite significant quality improvement efforts to streamline in-hospital acute stroke care in the conventional model, there remain inherent layers of treatment delays, which could be eliminated with prehospital diagnostics and therapeutics administered in a mobile stroke unit. Early diagnosis using telestroke and neuroimaging while in the ambulance may enable targeted routing to hospitals with specialized care, which will likely improve patient outcomes. Key clinical trials in telestroke, mobile stroke units with prehospital neuroimaging capability, prehospital ultrasound and co-administration of various classes of neuroprotectives, antiplatelets and antithrombin agents with intravenous thrombolysis are discussed in this article.

Silencing of Id2 attenuates hypoxia/ischemia-induced neuronal injury via inhibition of neuronal apoptosis

Cerebral ischemic stroke has long been recognized as a prevalent and serious neurological disease that was associated with high mortality and morbidity. However, the current therapeutic protocols remain suboptimal with major mechanisms underlying stroke urgently warranted. Inhibitor of DNA binding/differentiation 2 (Id2) is found to be up-regulated in neuronal cells following hypoxia/ischemia (H/I). This study was aimed to investigate whether knockdown of Id2 in neuronal cells could protect them from hypoxic and ischemic injury both in vitro and in vivo. Flow cytometric analysis was employed to assess neuronal apoptosis in CoCl2-treated neuroblastoma B35 cells engineered to overexpress or knockdown Id2 expression. In vivo knockdown of Id2 was performed in Sprague-Dawley rats by a single intracerebroventricular injection of Cy3-labeled and cholesterol-modified Id2-siRNA. We found that knockdown of Id2 attenuated H/I-induced neuronal apoptosis in vitro while overexpression of Id2 produced an opposite effect. In a rat model of middle cerebral artery occlusion (MCAO), in vivo knockdown of Id2 significantly improved neurological deficits, reduced the volume of ischemic infarction and diminished the neuronal apoptosis in the penumbra area. Double immunofluorescence staining showed less co-localization of retinoblastoma tumor suppressor protein (Rb)-Id2 but greater co-localization of Rb-E2F1 in the penumbra area. Cell cycle assay further demonstrated that Id2 knockdown induced G0/G1 cell cycle arrest in CoCl2-treated B35 cells. The present data support the implication of Id2 in the modulation of H/I-induced neuronal apoptosis and may provide a potential therapeutic option to protect brain tissues from ischemic injury by inhibition of its expression.

A Mobile Stroke Treatment Unit for Field Triage of Patients for Intraarterial Revascularization Therapy

INTRODUCTION

Favorable outcomes in intraarterial therapy (IAT) for acute ischemic stroke (AIS) are related to early vessel recanalization. The mobile stroke treatment unit (MSTU) is an on-site, prehospital, treatment team, laboratory, and CT scanner that reduces time to treatment for intravenous thrombolysis and may also shorten time to IAT.

METHODS

Using our MSTU database, we identified patients that underwent IAT for AIS. We compared the key time metrics to historical controls, which included patients that underwent IAT at our institution six months prior to implementation of the MSTU. We further divided the controls into two groups: (1) transferred to our institution for IAT and (2) directly presented to our emergency room and underwent IAT.

RESULTS

After 164 days of service, the MSTU transported 155 patients of which 5 underwent IAT. We identified 5 historical controls that were transferred to our center for IAT. Substantial reduction in times including median door to initial CT (12 minute vs. 32 minute), CT to IAT (82 minute vs. 165 minute), and door to MSTU/primary stroke center departure (37 minute vs. 106 minute) were noted among the two groups. Compared to the 6 patients who presented to our institution directly, the MSTU process times were also shorter.

CONCLUSION

Our initial experience shows that MSTU may help in early triage and shorten the time to IAT for AIS.

Lean thinking turns ‘time is brain’ into reality

Intravenous rt-PA is an effective recanalizing treatment for ischemic stroke within 4 and half hours from its onset (Onset-to-Treatment [OTT]), with the best result seen in those treated within 90 minutes OTT. Yet few patients currently are treated in this time frame. From the standpoint of process improvement or a lean thinking perspective, there is a potential opportunity to reduce the time by eliminating non-value-added steps in each element of the stroke survival chain. The reduction in one time element does not necessarily shift the OTT under 90 minutes. Most likely, the reduction in OTT requires a coordinated approach to track and improve all elements of OTT, from the patient’s ability to recognize the onset of stroke up to delivery of medication. Shortening this total time should be a considered an indicator of quality improvement in acute stroke care.

Intra-arterial therapy for acute ischemic stroke: a golden age

OPINION STATEMENT

With the recent publication of multiple trials demonstrating the superiority of the endovascular treatment of patients presenting with stroke from large vessel occlusion (LVO) over medical management, the emergent care of these patients is entering a new era. This realization justifies an aggressive treatment approach with these stroke patients, given the poor natural history of the disease. In general, treatment should occur as quickly as is reasonably possible. Patients with NIHSS >8 should be considered, and if <6 h from onset imaging selection achieved with CT and CTA. Those with ASPECTS >5, LVO and intermediate or good collaterals should be treated emergently. For patients with clinical deficits presenting in later timeframes MRI should be used to define core infarct size and therefore treatment eligibility. MRI might also be considered for the workup of stroke patients in centers that can offer it rapidly. Recanalization should be attempted with a stentriever or using a direct aspiration technique, with the patient under conscious sedation rather than general anesthesia, if that is a safe option. Angiographically, the goal is reperfusion of mTICI 2b/3. Post-procedure, the patient should be admitted to an intensive care setting and assessed for inpatient rehabilitation placement as soon as stable. Continuous institutional process improvement ensures that optimization of treatment times and logistics is an ongoing endeavor. Finally, patient outcomes should be assessed at three months, most commonly using the modified Rankin score.

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.

Recovery of CT stroke hypodensity--An adaptive variational approach

The present research was directed to effective image restoration with the extraction of ischemic edema signs. Computerized support of hyperacute stroke diagnosis based on routinely used computerized tomography (CT) scans was optimized to visualize the infarct extent more precisely. In particular, a beneficial support of time-limited appropriate decision of whether to treat the patient by thrombolysis is expected. Because of a limited accuracy in determining the area of core infarction, particularly in the early hours of symptoms' onset, a variational approach to sensed data recovery was applied. Proposed methodology adjusts fidelity norms and regularization priors integrated with simulated sensing procedures in a compressed sensing framework. Experimental study confirmed almost perfect recognition of ischemic stroke in a test set of over 500 CT scans.

Postischemic hyperperfusion on arterial spin labeled perfusion MRI is linked to hemorrhagic transformation in stroke

The purpose of this study was to investigate the relationship between hyperperfusion and hemorrhagic transformation (HT) in acute ischemic stroke (AIS). Pseudo-continuous arterial spin labeling (ASL) with background suppressed 3D GRASE was performed during routine clinical magnetic resonance imaging (MRI) on AIS patients at various time points. Arterial spin labeling cerebral blood flow (CBF) maps were visually inspected for the presence of hyperperfusion. Hemorrhagic transformation was followed during hospitalization and was graded on gradient recalled echo (GRE) scans into hemorrhagic infarction (HI) and parenchymal hematoma (PH). A total of 361 ASL scans were collected from 221 consecutive patients with middle cerebral artery stroke from May 2010 to September 2013. Hyperperfusion was more frequently detected posttreatment (odds ratio (OR) = 4.8, 95% confidence interval (CI) 2.5 to 8.9, P < 0.001) and with high National Institutes of Health Stroke Scale (NIHSS) scores at admission (P<0.001). There was a significant association between having hyperperfusion at any time point and HT (OR = 3.5, 95% CI 2.0 to 6.3, P < 0.001). There was a positive relationship between the grade of HT and time-hyperperfusion with the Spearman's rank correlation of 0.44 (P = 0.003). Arterial spin labeling hyperperfusion may provide an imaging marker of HT, which may guide the management of AIS patients post tissue-type plasminogen activator (tPA) and/or endovascular treatments. Late hyperperfusion should be given more attention to prevent high-grade HT.

Cost-effectiveness estimate of prehospital thrombolysis: results of the PHANTOM-S study

OBJECTIVE

To analyze the cost-effectiveness of shorter delays to treatment and increased thrombolysis rate as shown in the PHANTOM-S (Prehospital Acute Neurological Treatment and Optimization of Medical Care in Stroke) Study.

METHODS

In addition to intermediate outcomes (time to thrombolysis) and treatment rates, we registered all resource consequences of the intervention. The analyzed treatment effects of the intervention were restricted to distribution of IV thrombolysis (IVT) administrations according to time intervals. Intermediate outcomes were extrapolated to final outcomes according to numbers needed to treat derived from pooled IVT trials and translated to gains in quality-adjusted life-years (QALYs).

RESULTS

The net annual cost of the Stroke Emergency Mobile (STEMO) prehospital stroke concept was €963,954. The higher frequency of IVT administrations per year (310 vs 225) and higher proportions of patients treated in the early time interval (within 90 minutes: 48.1% vs 37.4%; 91-180 minutes: 37.4% vs 50%; 181-270 minutes: 14.5% vs 12.8%) resulted in an annual expected health gain of avoidance of 18 cases of disability equaling 29.7 QALYs. This produced an incremental cost-effectiveness ratio of €32,456 per QALY.

CONCLUSIONS

Depending on willingness-to-pay thresholds in societal perspectives, the STEMO prehospital stroke concept has the potential of providing a reasonable innovation even in health-economic dimensions.

Improved prehospital triage of patients with stroke in a specialized stroke ambulance: results of the pre-hospital acute neurological therapy and optimization of medical care in stroke study

BACKGROUND AND PURPOSE

Specialized management of patients with stroke is not available in all hospitals. We evaluated whether prehospital management in the Stroke Emergency Mobile (STEMO) improves the triage of patients with stroke.

METHODS

STEMO is an ambulance staffed with a specialized stroke team and equipped with a computed tomographic scanner and point-of-care laboratory. We compared the prehospital triage of patients with suspected stroke at dispatcher level who either received STEMO care or conventional care. We assessed transport destination in patients with different diagnoses. Status at hospital discharge was used as short-term outcome.

RESULTS

From May 2011 to January 2013, 1804 of 6182 (29%) patients received STEMO care and 4378 of 6182 (71%) patients conventional care. Two hundred forty-five of 2110 (11.6%) patients with cerebrovascular events were sent to hospitals without Stroke Unit in conventional care when compared with 48 of 866 (5.5%; P<0.01%) patients in STEMO care. In patients with ischemic stroke, STEMO care reduced transport to hospitals without Stroke Unit from 10.1% (151 of 1497) to 3.9% (24 of 610; P<0.01). The delivery rate of patients with intracranial hemorrhage to hospitals without neurosurgery department was 43.0% (65 of 151) in conventional care and 11.3% (7 of 62) in STEMO care (P<0.01). There was a slight trend toward higher rates of patients discharged home in neurological patients when cared by STEMO (63.5% versus 60.8%; P=0.096).

CONCLUSIONS

The triage of patients with cerebrovascular events to specialized hospitals can be improved by STEMO ambulances.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT01382862.

Emergency and critical care management of acute ischaemic stroke

Ischaemic stroke is a devastating condition that is the leading cause of disability in the USA. Over the last 2 decades, the focus of management has shifted from secondary stroke prevention to acute treatment. Coordinated care starts in the field with the emergency medical service providers and continues in the ambulance and the emergency department through to the intensive care unit. After diagnosis and stabilization, a major goal is reperfusion therapy with intravenous fibrinolytics. Neuroimaging research is focused on improving patient selection, expanding treatment windows, and increasing the safety of therapeutic intervention. The role of adjunctive intra-arterial and mechanical thrombectomy remains undefined, and methods to improve reperfusion using sonolysis and new-generation fibrinolytics are currently investigational. Treatment in the intensive care unit targets prevention of secondary brain injury through optimization of blood pressure, cerebral perfusion, glucose, and temperature management, ventilation, and oxygenation. The most feared complications include malignant cerebral edema and symptomatic hemorrhagic transformation. Decompressive craniectomy is life saving, but questions regarding patient selection and timing remain. Hyperosmolar agents are currently used to mitigate cerebral edema, but newer agents to prevent the formation of cerebral edema at the molecular level are being studied. We outline a practical approach to current emergency and intensive care management based on consensus guidelines and the best available evidence.

Advances in medical revascularisation treatments in acute ischemic stroke

Urgent reperfusion of the ischaemic brain is the aim of stroke treatment and there has been ongoing research to find a drug that can promote vessel recanalisation more completely and with less side effects. In this review article, the major studies which have validated the use and safety of tPA are discussed. The safety and efficacy of other thrombolytic and anticoagulative agents such as tenecteplase, desmoteplase, ancrod, tirofiban, abciximab, eptifibatide, and argatroban are also reviewed. Tenecteplase and desmoteplase are both plasminogen activators with higher fibrin affinity and longer half-life compared to alteplase. They have shown greater reperfusion rates and improved functional outcomes in preliminary studies. Argatroban is a direct thrombin inhibitor used as an adjunct to intravenous tPA and showed higher rates of complete recanalisation in the ARTTS study with further studies which are now ongoing. Adjuvant thrombolysis techniques using transcranial ultrasound are also being investigated and have shown higher rates of complete recanalisation, for example, in the CLOTBUST study. Overall, development in medical therapies for stroke is important due to the ease of administration compared to endovascular treatments, and the new treatments such as tenecteplase, desmoteplase, and adjuvant sonothrombolysis are showing promising results and await further large-scale clinical trials.

Is prehospital treatment of acute stroke too expensive? An economic evaluation based on the first trial

BACKGROUND

Recently, a strategy for treating stroke directly at the emergency site was developed. It was based on the use of an ambulance equipped with a scanner, a point-of-care laboratory, and telemedicine capabilities (Mobile Stroke Unit). Despite demonstrating a marked reduction in the delay to thrombolysis, this strategy is criticized because of potentially unacceptable costs.

METHODS

We related the incremental direct costs of prehospital stroke treatment based on data of the first trial on this concept to one year direct cost savings taken from published research results. Key parameters were configuration of emergency medical service personnel, operating distance, and population density. Model parameters were varied to cover 5 different relevant emergency medical service scenarios. Additionally, the effects of operating distance and population density on benefit-cost ratios were analyzed.

RESULTS

Benefits of the concept of prehospital stroke treatment outweighed its costs with a benefit-cost ratio of 1.96 in the baseline experimental setting. The benefit-cost ratio markedly increased with the reduction of the staff and with higher population density. Maximum benefit-cost ratios between 2.16 and 6.85 were identified at optimum operating distances in a range between 43.01 and 64.88 km (26.88 and 40.55 miles). Our model implies that in different scenarios the Mobile Stroke Unit strategy is cost-efficient starting from an operating distance of 15.98 km (9.99 miles) or from a population density of 79 inhabitants per km2 (202 inhabitants per square mile).

CONCLUSION

This study indicates that based on a one-year benefit-cost analysis that prehospital treatment of acute stroke is highly cost-effective across a wide range of possible scenarios. It is the highest when the staff size of the Mobile Stroke Unit can be reduced, for example, by the use of telemedical support from hospital experts. Although efficiency is positively related to population density, benefit-cost ratios can be greater than 1 even in rural settings.

Recent advances in TeleStroke: a systematic review on applications in prehospital management and Stroke Unit treatment or TeleStroke networking in developing countries

TeleStroke has become an increasing means to overcome shortage of stroke expertise in underserved areas. This rapidly growing field has triggered a large amount of publications in recent years. We aimed to analyze recent advances in the field of telemedicine for acute stroke, with main focus on prehospital management, Stroke Unit treatment and network implementations in developing countries. Out of 260 articles, 25 were selected for this systematic review: 9 regarding prehospital management, 14 regarding Stroke Unit treatment and 2 describing a network in developing countries. Prehospital management showed that stroke recognition can start at the dispatch emergency call, important clinical information can be electronically transmitted to hospitals before admission and even acute treatment such as thrombolysis can be initiated in the prehospital field if ambulances are equipped with CT scan and point-of-care laboratory. Articles on remote clinical examination, telemedical imaging interpretation, trial recruitment and cost-effectiveness described various aspects of Stroke Unit treatment within TeleStroke networks, underlining reliability, safety and cost savings of these systems of care. Only one network was described to have been implemented in a developing/emerging nation. TeleStroke is a growing field expanding its focus to a broader spectrum of stroke care. It still seems to be underused, particularly in developing countries.

Intravenous thrombolysis for acute ischemic stroke

Intravenous thrombolysis (IVT) with alteplase remains the standard treatment for acute ischemic stroke. Although IVT can be started up to 4.5 hours after symptoms' onset, it is all the more effective and safe when started early. It allows a 10% absolute reduction in the risk of handicap or death at 3 months, despite a 2-7% risk of symptomatic intracranial hemorrhage. Current research efforts involve firstly trying to treat a larger proportion of patients by overcoming some of the contraindications to IVT and secondly assessing combined or alternative treatments to achieve a higher early recanalization rate.