Hyperacute treatment initiation in neuroprotective agent stroke trials

Intravenous Magnesium Sulfate in Acute Stroke

Background and Purpose—

Acute stroke treatment is challenging, and stroke remains a major cause of death and disability. The purpose of this meta-analysis is to investigate the effects of postacute stroke intravenous administration of the neuroprotectant magnesium sulfate (MgSO 4 ) on global outcome, functional outcome, and mortality 90 days poststroke (ischemic and nonischemic).

Methods—

We searched in Pubmed, Science Direct, CENTRAL, and ClinicalTrials.gov, up to November 11, 2017, and we conducted a systematic review and meta-analysis of randomized controlled trials. We synthesized results by using random-effects model, weighted mean differences, standardized mean differences, and odds ratios.

Results—

Seven randomized controlled trials (4347 patients) met our criteria. Compared with placebo, treatment did not improve functional outcome defined as Barthel Index >60 (odds ratio =1.05; 95% CI, 0.92–1.19) and >95 (odds ratio =0.95; 95% CI, 0.76–1.20), 90 days poststroke. It also did not improve global outcome measured with modified Rankin Scale (standardized mean difference =−0.01; 95% CI, −0.12 to 0.10), 90 days poststroke. In an additional subgroup meta-analysis that exclusively included ischemic stroke patients, intravenous MgSO 4 resulted in lower modified Rankin Scale score (improved global outcome; weighted mean difference =−0.96; 95% CI, −1.34 to −0.58; I 2 =0%], 90 days poststroke. Finally, mortality stayed unaltered (odds ratio =1.10; 95% CI, 0.94–1.29).

Conclusions—

The findings of our meta-analysis showed that intravenous MgSO 4 generally did not improve global/functional outcomes and mortality at 90 days after stroke (combined ischemic stroke and nonischemic stroke). The finding of favorable neurological outcome, selectively in ischemic stroke patients, should be viewed with extreme caution given the limited number of patients included in this subgroup meta-analysis.

Major publications in the critical care pharmacotherapy literature in 2015

PURPOSE

Recently published practice guidelines and research reports on pharmacotherapy in critical care patient populations are summarized.

SUMMARY

The Critical Care Pharmacotherapy Literature Update (CCPLU) Group is composed of over 50 experienced critical care pharmacists who evaluate 31 peer-reviewed journals monthly to identify literature pertaining to pharmacotherapy in critical care populations. Articles are chosen for summarization in a monthly CCPLU Group publication on the basis of applicability and relevance to clinical practice and strength of study design. From January to December 2015, a total of 121 articles were summarized; of these, 3 articles presenting clinical practice guidelines and 12 articles presenting original research findings were objectively selected for inclusion in this review based on their potential to change or reinforce current evidence-based practice. The reviewed guidelines address the management of intracranial hemorrhage (ICH), adult advanced cardiac life support (ACLS) and post-cardiac arrest care, and the management of supraventricular tachycardia (SVT). The reviewed research reports address topics such as nutrition in critically ill adults, administration of β-lactams for severe sepsis, anticoagulant selection in the context of continuous renal replacement therapy, early goal-directed therapy in septic shock, magnesium use for neuroprotection in acute stroke, and progesterone use in patients with traumatic brain injury.

CONCLUSION

Important recent additions to the critical care pharmacy literature include updated joint clinical practice guidelines on the management of spontaneous ICH, ACLS, and SVT.

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.

Prehospital use of magnesium sulfate as neuroprotection in acute stroke

BACKGROUND

Magnesium sulfate is neuroprotective in preclinical models of stroke and has shown signals of potential efficacy with an acceptable safety profile when delivered early after stroke onset in humans. Delayed initiation of neuroprotective agents has hindered earlier phase 3 trials of neuroprotective agents.

METHODS

We randomly assigned patients with suspected stroke to receive either intravenous magnesium sulfate or placebo, beginning within 2 hours after symptom onset. A loading dose was initiated by paramedics before the patient arrived at the hospital, and a 24-hour maintenance infusion was started on the patient's arrival at the hospital. The primary outcome was the degree of disability at 90 days, as measured by scores on the modified Rankin scale (range, 0 to 6, with higher scores indicating greater disability).

RESULTS

Among the 1700 enrolled patients (857 in the magnesium group and 843 in the placebo group), the mean (±SD) age was 69±13 years, 42.6% were women, and the mean pretreatment score on the Los Angeles Motor Scale of stroke severity (range, 0 to 10, with higher scores indicating greater motor deficits) was 3.7±1.3. The final diagnosis of the qualifying event was cerebral ischemia in 73.3% of patients, intracranial hemorrhage in 22.8%, and a stroke-mimicking condition in 3.9%. The median interval between the time the patient was last known to be free of stroke symptoms and the start of the study-drug infusion was 45 minutes (interquartile range, 35 to 62), and 74.3% of patients received the study-drug infusion within the first hour after symptom onset. There was no significant shift in the distribution of 90-day disability outcomes on the global modified Rankin scale between patients in the magnesium group and those in the placebo group (P=0.28 by the Cochran-Mantel-Haenszel test); mean scores at 90 days did not differ between the magnesium group and the placebo group (2.7 in each group, P=1.00). No significant between-group differences were noted with respect to mortality (15.4% in the magnesium group and 15.5% in the placebo group, P=0.95) or all serious adverse events.

CONCLUSIONS

Prehospital initiation of magnesium sulfate therapy was safe and allowed the start of therapy within 2 hours after the onset of stroke symptoms, but it did not improve disability outcomes at 90 days. (Funded by the National Institute of Neurological Disorders and Stroke; FAST-MAG ClinicalTrials.gov number, NCT00059332.).

Hypothermia protects human neurons

BACKGROUND AND AIMS

Hypothermia provides neuroprotection after cardiac arrest, hypoxic-ischemic encephalopathy, and in animal models of ischemic stroke. However, as drug development for stroke has been beset by translational failure, we sought additional evidence that hypothermia protects human neurons against ischemic injury.

METHODS

Human embryonic stem cells were cultured and differentiated to provide a source of neurons expressing β III tubulin, microtubule-associated protein 2, and the Neuronal Nuclei antigen. Oxygen deprivation, oxygen-glucose deprivation, and H2 O2 -induced oxidative stress were used to induce relevant injury.

RESULTS

Hypothermia to 33°C protected these human neurons against H2 O2 -induced oxidative stress reducing lactate dehydrogenase release and Terminal deoxynucleotidyl transferase dUTP nick end labeling-staining by 53% (P ≤ 0·0001; 95% confidence interval 34·8-71·04) and 42% (P ≤ 0·0001; 95% confidence interval 27·5-56·6), respectively, after 24 h in culture. Hypothermia provided similar protection against oxygen-glucose deprivation (42%, P ≤ 0·001, 95% confidence interval 18·3-71·3 and 26%, P ≤ 0·001; 95% confidence interval 12·4-52·2, respectively) but provided no protection against oxygen deprivation alone. Protection (21%) persisted against H2 O2 -induced oxidative stress even when hypothermia was initiated six-hours after onset of injury (P ≤ 0·05; 95% confidence interval 0·57-43·1).

CONCLUSION

We conclude that hypothermia protects stem cell-derived human neurons against insults relevant to stroke over a clinically relevant time frame. Protection against H2 O2 -induced injury and combined oxygen and glucose deprivation but not against oxygen deprivation alone suggests an interaction in which protection benefits from reduction in available glucose under some but not all circumstances.

Magnesium: potential roles in neurovascular disease

OBJECTIVE

Magnesium therapy has been studied extensively in pre-clinical and clinical trials in multiple organ systems. Cerebrovascular diseases may benefit from its neuroprotective properties. This review summarizes current studies of magnesium in a wide range of neurovascular diseases.

METHODS

We searched relevant terms in the National Library of Medicine PubMed database and selected research including basic science, translational reports, meta-analyses, and clinical studies.

RESULTS

Studies examining magnesium administration in ischemic stroke have failed to show any benefit in clinical outcome. Data on magnesium for intracerebral hemorrhage (ICH) are limited. Preliminary investigations in subarachnoid hemorrhage (SAH) were promising, but definitive studies did not reveal differences in clinical outcome between magnesium and placebo-treated groups. Studies examining magnesium administration in global ischemia following cardiac arrest suggest a trend toward improved clinical outcome. The strongest evidence for clinically relevant neuroprotection following magnesium administration derives from studies of pre-term infants and patients undergoing cardiac bypass and carotid endarterectomy procedures. Magnesium was found to have an excellent safety profile across all investigations.

CONCLUSION

Magnesium is easy to administer and possesses a favorable safety profile. Its utility as a neuroprotectant in cardiac surgery, carotid endarterectomy, and pre-term infant hypoxia remain promising. Value as a therapeutic agent in ischemic stroke, ICH, and SAH is unclear and appears to be limited by late administration. Ongoing clinical trials assessing magnesium administration in the first hours following symptom onset may help clarify the role of magnesium therapy in these disease processes.

Methodology of the Field Administration of Stroke Therapy - Magnesium (FAST-MAG) phase 3 trial: Part 1 - rationale and general methods

RATIONALE

Prehospital initiation by paramedics may enable delivery of neuroprotective therapies to stroke patients in the hyperacute period when they are most effective in preclinical studies. Magnesium is neuroprotective in experimental stroke models and has been shown to be safe with signals of potential efficacy when started early after onset of human cerebral ischemia.

AIMS

(a) To demonstrate that paramedic initiation of the neuroprotective agent magnesium sulfate in the field is an efficacious and safe treatment for acute stroke; (b) To demonstrate that field enrollment of acute stroke patients is a practical and feasible strategy for phase 3 stroke trials, permitting enrollment of greater numbers of patients in hyperacute time windows.

DESIGN

Multicenter, randomized, double-blinded, placebo-controlled, pivotal clinical trial.

STUDY PROCEDURES

The study is enrolling 1700 patients (850 in each arm) with likely acute stroke, including both cerebral infarction and intracerebral hemorrhage patients. Inclusion criteria are: (a) likely stroke as identified by the modified Los Angeles Prehospital Stroke Screen (mLAPSS), (b) age 40-95, (c) symptom onset within 2 h of treatment initiation, and (d) deficit present ≥15 min. Paramedics administer a loading dose of magnesium sulfate (Mg) or matched placebo in the field, 4 grams over 15 min. In the Emergency Department, a maintenance infusion follows, 16 grams Mg or matched placebo over 24 h.

OUTCOMES

The primary endpoint is the modified Rankin Scale measure of global disability, assessed using the Rankin Focused Assessment, 90 days after treatment. Secondary efficacy endpoints include the NIHSS (neurologic deficit), Barthel Index (activities of daily living), and the Stroke Impact Scale (quality of life).

Delayed treatment with a novel neurotrophic compound reduces behavioral deficits in rabbit ischemic stroke

Acute ischemic stroke is a major risk for morbidity and mortality in our aging population. Currently only one drug, the thrombolytic tissue plasminogen activator, is approved by the US Food and Drug Administration to treat stroke. Therefore, there is a need to develop new drugs that promote neuronal survival following stroke. We have synthesized a novel neuroprotective molecule called CNB-001 (a pyrazole derivative of curcumin) that has neurotrophic activity, enhances memory, and blocks cell death in multiple toxicity assays related to ischemic stroke. In this study, we tested the efficacy of CNB-001 in a rigorous rabbit ischemic stroke model and determined the molecular basis of its in vivo activity. CNB-001 has substantial beneficial properties in an in vitro ischemia assay and improves the behavioral outcome of rabbit ischemic stroke even when administered 1 h after the insult, a therapeutic window in this model comparable to tissue plasminogen activator. In addition, we elucidated the protein kinase pathways involved in neuroprotection. CNB-001 maintains the calcium-calmodulin-dependent kinase signaling pathways associated with neurotrophic growth factors that are critical for the maintenance of neuronal function. On the basis of its in vivo efficacy and novel mode of action, we conclude that CNB-001 has a great potential for the treatment of ischemic stroke as well as other CNS pathologies.

Taking a light approach to treating acute ischemic stroke patients: transcranial near-infrared laser therapy translational science

Transcranial near-infrared laser therapy (NILT) has been investigated as a novel neuroprotective treatment for acute ischemic stroke (AIS), for approximately 10 years. Two clinical trials, NeuroThera Effectiveness and Safety Trial (NEST)-1 and NEST-2, have evaluated the use of NILT to promote clinical recovery in patients with AIS. This review covers preclinical, translational, and clinical studies documented during the period 1997-2010. The primary aim of this article is to detail the development profile of NILT to treat AIS. Secondly, insight into possible mechanisms involved in light therapy will be presented. Lastly, possible new directions that should be considered to improve the efficacy profile of NILT in AIS patients will be discussed. The use of NILT was advanced to clinical trials based upon extensive translational research using multiple species. NILT, which may promote functional and behavioral recovery via a mitochondrial mechanism and by enhancing cerebral blood flow, may eventually be established as an Food and Drug Administration (FDA)-approved treatment for stroke. The NEST-3 trial, which is the pivotal trial for FDA approval, should incorporate hypotheses derived from translational studies to ensure efficacy in patients. Future NILT studies should consider administration of a thrombolytic to enhance cerebral reperfusion alongside NILT neuroprotection.

Simultaneous ring voice-over-Internet phone system enables rapid physician elicitation of explicit informed consent in prehospital stroke treatment trials

BACKGROUND

Cellular phone conversations between on-scene patients or their legally authorized representatives (LARs) and off-scene enrolling physician-investigators require immediate and reliable connection systems to obtain explicit informed research consent in prehospital treatment trials.

METHODS

The NIH Field Administration of Stroke Therapy-Magnesium (FAST-MAG) Trial implemented a voice-over-internet protocol (VOIP) simultaneous ring system (multiple investigator cell phones called simultaneously and first responder connected to call) to enable physician-investigators to elicit consent immediately from competent patients or LARs encountered by 228 ambulances enrolling patients in a multicenter prehospital stroke trial. For 1 month, the number, origin, duration, and yield of enrolling line calls were monitored prospectively.

RESULTS

Six investigators were connected to 106 enrolling line calls, with no identified unanswered calls. Thirty-five percent of new patient calls yielded an enrollment. The most common reasons for non-enrollment were last known well >2 h (n = 7) and unconsentable patient without LAR available (n = 7). No non-enrollments were directly attributable to the VOIP system. In enrollments, consent was provided by the patient in 67% and a LAR in 33%. The duration of enrollment calls (mean +/- SD: 8.4 +/- 2.5 min, range 6-14) was longer than non-enrollment calls (5.5 +/- 3.5, range 2-13; p < 0.001). The median interval from last known well to study agent start was 46 min, and 70% were enrolled within 60 min of onset.

CONCLUSIONS

The simultaneous ring system was reliable and effective, permitting enrollment of a substantial number of patients within the first hour after stroke onset. VOIP cellular networks with simultaneous ring are a preferred means of facilitating consent in prehospital treatment trials.

Physician-Investigator Phone Elicitation of Consent in the Field: A Novel Method To Obtain Explicit Informed Consent For Prehospital Clinical Research

OBJECTIVE

To describe and report the feasibility of a novel field telephonic strategy to elicit explicit informed consent in prehospital trials for conditions in which patients retain decision-making capacity.

METHODS

In a pilot prehospital neuroprotective stroke therapy trial, ambulances carried written informed consent forms and dedicated trial cellular phones permitting rapid connection to on call physician-investigators. The physician-investigator discussed the trial with the consent provider [patient if competent, on scene legally authorized representative (LAR) if patient not competent] by phone, while paramedics carried out prehospital care duties unimpeded.

RESULTS

32 patients met consent elicitation criteria. 20 (63%) were enrolled. The most frequent reasons for non-enrollment were: patient not competent and no available on-scene LAR-5; patient/LAR declined participation-4. Among enrollees, 15 (75%) were competent and self-enrolled; 5 (25%) were not competent and were enrolled by LAR family members. Site of consent initiation was: patient home-15 (74 = 5%), work-2(10)%, other-3(15)%. Consent was elicited via cell phone in 11 (55%) and site landline in 9 (45%). Compared with patients enrolled in prior studies employing standard in-hospital consent, prehospital consent procedures reduced time from paramedic arrival on-scene to start of study agent (26 vs 139 mins, p < 0.0001), and did not prolong the on-scene to ED arrival time (37 vs 34 min, p = 0.50). No patient/family withdrew consent during the 3-month follow-up period.

CONCLUSION

Physician phone elicitation of prehospital research consent from individuals with retained competency or on-scene legally authorized representatives is feasible, permits rapid patient study entry, and does not delay field transport times.