Clinical trial NCT03176823: Remote Ischemic Conditioning as a Treatment for Traumatic Brain Injury
Official title: Remote Ischemic Conditioning as a Treatment for Traumatic Brain Injury: a Prospective Randomized Controlled Trial.
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Traumatic Brain Injury
Trauma, Nervous System
Reperfusion Injury
Ischemia, Brain
Keywords: Brain injury
Remote ischemic conditioning (RIC)
Trauma
Biomarkers
Lead sponsor: Unity Health Toronto
Sponsor class: OTHER
Collaborators: name: Defence Research and Development Canada
First posted: 2017-06-06
Enrollment: 44
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: This trial is a prospective double-blind parallel cohort study of patients undergoing either standard of care plus placebo (sham-RIC) or standard treatment plus a single session of upper extremity remote ischemic conditioning.
Primary purpose: TREATMENT

Brief summary: The prevention of secondary brain injury is a primary goal in treating patients with severe traumatic brain injury (TBI). Secondary brain injury results from tissue ischemia induced by increased vascular resistance in the at-risk brain tissue due to compression by traumatic hematomas, and development of cytotoxic and vasogenic tissue edema. While traumatic hematomas may be managed surgically, cytotoxic and vasogenic edema with resulting perfusion impairment perpetuates brain ischemia and injury. Animal models suggest that remote ischemic conditioning (RIC) can reverse these effects and improve perfusion. Based on these findings it is hypothesized that RIC will exert beneficial effects on TBI in man, thereby representing a new therapeutic strategy for severe TBI.

Patients presenting to our institution suffering from severe TBI will be considered for enrollment. Eligible patients will have sustained a blunt, severe TBI (defined by Glasgow Coma Scale \<8) with associated intra-cranial hematoma(s) not requiring immediate surgical decompression, with admission to an intensive care unit and insertion of an intra-cranial pressure monitor. Patients will be randomized to RIC versus sham-RIC intervention cohorts. RIC interventions will be performed using an automated device on the upper extremity delivering 20 cumulative minutes of limb ischemia in a single treatment session. The planned enrollment is a cohort of 40 patients.

Outcomes of this study will include multiple domains. Our primary outcome will include serial assessments of validated serum biomarkers of neuronal injury and systemic inflammation. Secondary outcomes will include descriptions of the clinical course of each patient, radiologic assessment of brain perfusion, and neurocognitive and psychological assessment post-discharge.

If clinical outcomes are improved using RIC, this study would support RIC as a novel treatment for TBI. Its advantages include safety and simplicity and, requiring no specialized equipment, its ability to be used in any environment including pre-hospital settings or in austere theatres. The investigators anticipate that TBI patients treated with RIC will have improved clinical, biochemical, and neuropsychological outcomes compared to standard treatment protocols.

Detailed description: Traumatic brain injury is a leading cause of morbidity and mortality in victims of blunt trauma, leading to a tremendous economic cost, chronic neuropsychological sequelae and productive years of life lost. Treatment of inoperable primary brain injury consists largely of supportive care to support natural healing and prevention or reduction of secondary insults (1).

Many of the phenomena of secondary injury are related to ischemic sequelae of injury progression. Brain parenchymal edema increases both regional and global intra-cranial pressures, decreasing perfusion pressure, resulting in impaired perfusion, an oxygen debt, and ischemic injury (2). Local compression from traumatic hematomas may act in concert with edema to further impair perfusion. One strategy that has been successfully employed in the treatment of other ischemic insults is an intervention known as "remote ischemic conditioning" (RIC). RIC is felt to induce systemic responses which promote physiologic adaptations to moderate ischemia and minimize the impact of subsequent ischemic insults. Because these effects are systemic, extremity ischemic conditioning may impact brain injury. In the setting of TBI, where all patients carry a risk of ischemic secondary injury, early intervention with RIC may minimize the harm of secondary ischemic insults and improve outcomes.

The systemic effects of RIC have been demonstrated in a variety of organ systems and mechanisms of ischemia. Application of RIC has demonstrable benefits in preventing ischemia-induced organ dysfunction in insults to the heart (3-6), kidneys (7,8), and ocular organ systems (9). Our recent work has demonstrated its benefit in preventing organ injury following hemorrhagic shock (10). The technique has also demonstrated promise in reducing brain injury secondary to stroke or neurosurgical trauma (11-13).

Ischemic conditioning of brain injuries has proven benefits in animal models. Limb preconditioning reduces toxic oxygen free radicals, reduces neuronal apoptosis, reduces intra-cranial inflammation, improves integrity of the blood-brain barrier, and reduces brain parenchymal edema (14,15). RIC also improves microvascular perfusion to ischemic tissues which, in the brain, may reduce secondary injury by promoting perfusion to the at-risk injured brain (16). Even when performed after the intra-cranial trauma in a "post-conditioning" model, limb ischemic conditioning is associated with decreased apoptosis, decreased edema, and decreased brain infarction volumes (17,18). A single recent trial of RIC in human TBI patients showed a decrease in serum biomarkers of central nervous system (CNS) injury in the conditioned cohort (19).

Given the promising findings of the remote ischemic conditioning technique in reducing biomarkers of intra-cranial inflammation, an assessment of the clinical effectiveness of post-traumatic remote ischemic conditioning in modifying the outcomes of patients with isolated severe traumatic brain injuries is warranted.

Outcomes of this proposed prospective, randomized controlled trial will fall into the following validated categories:

1. Biomarkers of neuronal injury and systemic inflammation (20-28)
2. Radiologic evidence of improved acute- and delayed-phase perfusion (29-33)
3. Clinical course in hospital from admission to discharge
4. Neurocognitive and neuropsychological outcomes, 6 month follow-up (34-46)

The known physiologic effects of RIC are theoretically beneficial to patients suffering severe TBI who are at risk of clinical deterioration due to secondary injury. By mitigating the effects of inflammation and edema and improving microvascular perfusion, at-risk brain tissue may be salvaged and thus patient outcomes improved. This theory is supported by the existing evidence and a well-planned selection of outcome measures including biochemical, clinical, and radiographic outcomes may demonstrate the benefits of RIC in this patient population.

Eligibility criteria: Inclusion Criteria:

* Severe blunt traumatic brain injury presenting to St Michael's Hospital within 48 hours of trauma
* Glasgow Coma Scale (GCS) less than or equal to 12
* Presence on CT Scan of intra-cranial hematoma which adequately explains level of consciousness (epidural, subdural, subarachnoid hematomae)
* Able to undergo intervention within 48 hours of trauma

Exclusion Criteria:

* Age \<18 years
* Lack of informed consent or withdrawal of consent, provided by legal substitute decision maker
* Unknown timing of trauma
* Unable to safely undergo ischemic conditioning of the upper extremity due to major trauma, previous surgery, known vascular disease or previous radiation treatment
* Acute significant injury (those injuries which in isolation would require admission to hospital) outside the head and neck region
* Pre-hospital therapeutic anticoagulation or anti-platelet agent use
* Surgical intervention within 12 hours of presentation to hospital, excluding pressure monitor insertion
* Patient death within 24 hours of admission
* Pre-intervention insertion of intra-cranial pressure monitor, as surgical trauma may influence biomarker measurements

Primary outcomes:
measure: Neuron Specific Enolase (NSE) - biomarker
timeFrame: Admission (0 hours), 6 hours, 24 hours, 48 hours, and 72 hours
measure: S100A12 - biomarker
timeFrame: Admission (0 hours), 6 hours, 24 hours, 48 hours, and 72 hours
measure: Calcium Binding Protein Beta (S100B) - biomarker
timeFrame: Admission (0 hours), 6 hours, 24 hours, 48 hours, and 72 hours
measure: Glial Fibrillary Acidic Protein (GFAP) - biomarker
timeFrame: Admission (0 hours), 6 hours, 24 hours, 48 hours, and 72 hours
measure: Monocyte Chemoattractant Protein (MCP1) - biomarker
timeFrame: Admission (0 hours), 6 hours, 24 hours, 48 hours, and 72 hours
measure: Epinephrine - biomarker
timeFrame: Admission (0 hours), 6 hours, 24 hours, 48 hours, and 72 hours
measure: Norepinephrine - biomarker
timeFrame: Admission (0 hours), 6 hours, 24 hours, 48 hours, and 72 hours
measure: Interleukin 10 (IL10) - biomarker
timeFrame: Admission (0 hours), 6 hours, 24 hours, 48 hours, and 72 hours
measure: Interleukin 1 Beta (IL1B) - biomarker
timeFrame: Admission (0 hours), 6 hours, 24 hours, 48 hours, and 72 hours
measure: Tumor Necrosis Factor Alpha (TNF Alpha) - biomarker
timeFrame: Admission (0 hours), 6 hours, 24 hours, 48 hours, and 72 hours
measure: International Normalized Ratio (INR) - standard lab test.
timeFrame: Admission (0 hours), 6 hours, 24 hours, 48 hours, and 72 hours
measure: Prothrombin Time (PTT) - standard lab test.
timeFrame: Admission (0 hours), 6 hours, 24 hours, 48 hours, and 72 hours
measure: Rotational Thromboelastometry (ROTEM), standard lab test.
timeFrame: Admission (0 hours), 6 hours, 24 hours, 48 hours, and 72 hours
Secondary outcomes:
measure: Cerebral vascular perfusion, acute
timeFrame: 24 hours
measure: Intracranial Pressure (ICP) measurement, first 24 hours
timeFrame: 24 hours
measure: Intracranial Pressure (ICP) measurement, 24-96 hours
timeFrame: 24 hours, 96 hours
measure: Escalation along an established care algorithm
timeFrame: 12 months
measure: Mortality beyond 12 hours post-admission
timeFrame: 12 months
measure: Incidence of surgical decompression beyond 12 hours post-admission
timeFrame: 12 months
measure: Hospital length of stay, number of days
timeFrame: 12 months
measure: Intensive Care Unit length of stay, number of days
timeFrame: 2 months
measure: Total duration of mechanical ventilation, number of days
timeFrame: 2 months
measure: Destination of discharge
timeFrame: 12 months
measure: Glasgow Outcomes Scale, Extended (GOSE) - neurocognitive test
timeFrame: discharge, 3 months, 6 months, and 12 months
measure: Disability Rating Scale (DRS) - neurocognitive function rating
timeFrame: discharge, 3 months, 6 months, and 12 months
measure: Patient Health Questionnaire 9th edition (PHQ-9) - neurological - self assessment
timeFrame: discharge, 3, 6, and 12 months
measure: Posttraumatic Stress Disorder Checklist for the Diagnostic and Statistical Manual of Mental Disorders 5th edition (PCL-5) - neurological - self assessment
timeFrame: discharge, 3 months, 6 months, and 12 months
Other outcomes:
Locations:
city: Toronto
country: Canada
facility: St Michaels Hospital
state: Ontario
Study officials:
affiliation: Unity Health Toronto - St. Michael's hospital
name: Ori D Rotstein, MD
role: PRINCIPAL_INVESTIGATOR
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