Blood And Clot Thrombectomy Registry And Collaboration (BACTRAC)

  • End date
    Mar 1, 2024
  • participants needed
  • sponsor
    Justin Fraser
Updated on 19 June 2022


This is a prospective open enrollment registry to evaluate arterial blood and thrombus removed during the standard thrombectomy procedure, which will then be used for the purposes of identifying biological markers, inflammatory cell infiltrates, and biological states in large vessel occlusive stroke in the human condition. The primary objectives are to evaluate the feasibility of obtaining distal clot blood during thrombectomy; develop a group of biosamples (blood and clots) to evaluate novel proteins, cell types, and cytokines in acute ischemic stroke in the human condition, and evaluate specific biomarkers, proteins, and leukocyte populations in stroke in the human condition. The study population will include up to 250 subjects. Male and female participants 18 years of age and older will be enrolled. Participants must have had a suspected acute ischemic stroke based on clinical and radiographic evidence as determined and documented by the Stroke Neurology team at University of Kentucky. There is no therapeutic intervention involved in this study.

This is the first study to our knowledge that will utilize thrombectomy technique to collect focal blood samples and the clot related brain infarction. This proposal will provide preliminary data needed to understand relationships between the local inflammatory cascade and clinical variables such as age, gender, time from symptoms to thrombectomy, and stroke imaging results. Characterizing these relationships is vital in the formulation of related therapeutics. Issues of gender-differences, age-based variations, and co-morbidities all engender heterogeneity, which plague translation of stroke research from animal to human. By starting with the human condition, the investigators aim to minimize this loss in translation. Overall, this study will have a great impact on our knowledge of stroke pathology. In essence, this could fundamentally change not only how the investigators develop treatment strategies for the stroke patient population but allow us to individualize the treatment dependent on time after stroke, age, sex, and co-morbidities. Molecular techniques that are impractical when delivered systemically could be delivered locally to impede the early inflammation.


This study represents the first time that clot and blood will be evaluated for the markers, proteins, and cytokines listed in the protocol in human subjects undergoing thrombectomy for emergent large vessel occlusion stroke. The study is an open, unblinded, clinical and biologic registry to evaluate specific questions that are novel to understanding stroke in the human condition. There is no therapeutic intervention involved in this study. The study population will include up to 250 subjects enrolled at the University of Kentucky. The primary endpoints of the study will be evaluation of specific proteins and leukocyte populations in the human stroke clot and blood. Secondary endpoints include: Acid/Base Balance: Evaluate pH of blood as a marker of acid/base balance in distal blood and proximal blood, and correlate to interval of time between Last Known Normal and vessel recanalization; Inpatient Biomarker; Protein, RNA, expression with Clinical Correlation.

Participants will be recruited from patients evaluated at University of Kentucky Chandler Hospital for acute ischemic stroke. Participants with impaired capacity may be included as the pathology to be studied (stroke) may impair their capacity.

The study events occur during the acute hospitalization for the subject's condition (acute ischemic stroke).

Baseline (Day 0):

  • Verify inclusion/exclusion criteria
  • The patient or the Legally Authorized Representative (LAR) will be consented within 24 hours following the standard of care thrombectomy procedure.
  • Medical history taken from medical record, participant and family to determine eligibility based on inclusion/exclusion criteria (Standard of Care)
  • Medication history (Standard of Care)
  • Baseline physical examination to include vital signs (Standard of Care)
  • Premorbid Modified Ranking Score (mRS)
  • NIH Stroke Scale (Standard of Care)
  • BMI (Body Mass Index) (Standard of Care)
  • Obtain consent from the patient or Legally Authorized Representative (LAR)
  • Cerebral angiogram with Endovascular Thrombectomy (Standard of Care)
  • Study Specimen Collection as detailed below

Datapoints recorded will include the vessel location of the thrombus and time from Last Known Normal to vessel recanalization, along with TICI (Thrombolysis in Cerebral Infarction) score.

Study Specimen Collection

  1. Once a subject is determined by clinical staff to require thrombectomy, the thrombectomy pager will be activated. Since potential subjects arrive at any time of day, approximately 10 researchers will share call responsibilities. Once paged, the on-call researcher will attend the thrombectomy procedure.
  2. During the procedure, the neurointerventionalist will retain three samples, which are removed during the thrombectomy procedure:
  3. 1 cc of blood obtained from the microcatheter distal to the clot prior to thrombectomy (see Figure 1) 2. The thrombus itself (normally discarded) 3. 5 cc of whole blood from arterial guide catheter placed for the thrombectomy procedure. This represents a small amount of the blood typically removed/lost during the suction aspiration performed at the guide catheter. No separate venipuncture or arterial puncture will be necessary.
  4. The on-call researcher will retrieve the blood samples and thrombus. The samples will be collected, processed, and aliquoted by the researcher in a manner that will not delay or slow the thrombectomy procedure. In addition to the samples, a separate researcher will enter clinical data points on each subject into a REDCap (Research Electronic Data Capture) database.

All endpoints listed below are standard of care for followup after thrombectomy.

The following clinical endpoints will be captured:

  1. Date of Birth
  2. Age at enrollment
  3. Gender
  4. Race/ethnicity
  5. Height
  6. Weight
  7. Body Mass Index (BMI)
  8. Premorbid Modified Rankin Score (mRS)
  9. Location of the thrombus (e.g. M1 segment of middle cerebral artery) and source of the thrombus (cardioembolic, intracranial stenosis, dissection, carotid occlusion, infection, unknown).
  10. Presence of tandem occlusion of the cervical artery proximal to the thrombus
  11. Time from last known normal to thrombectomy completion (reopening of the vessel)
  12. Thrombectomy success as rated by TICI score
  13. NIH Stroke Scale prior to discharge
  14. Modified Rankin Score (mRS): premorbid, discharge, 90 days (Standard of Care)
  15. Mini-Montreal Cognitive Assessment (Mini-MoCA) or similar cognitive scale prior to discharge (Standard of Care)
  16. Medical comorbidities including hypertension, diabetes and hypercholesterolemia
  17. Volume of infarct
  18. Significant intracranial hemorrhage (defined as intracranial hemorrhage resulting in 4-point increase in NIH Stroke Scale or requiring surgical intervention)
  19. Petechial hemorrhages.
  20. Proximal (systemic) blood (pH - potential of hydrogen/acidity or basicity, pCO2 - carbon dioxide partial pressure, pO2 - oxygen partial pressure, pHCO3 - bicarbonate partial pressure, Na - sodium, K - potassium, Ca - Calcium)
  21. Distal blood (pH, pCO2, pO2, pHCO3, Na, K, Ca)
  22. Concomitant medications

Visit 1 (Within 48 hours)

MRI or CT is performed typically within 48 hours after thrombectomy as standard of care. Radiographic endpoints that will be captured include:

  1. Volume of infarct
  2. Significant intracranial hemorrhage (defined as intracranial hemorrhage resulting in 4-point increase in NIH Stroke Scale or requiring surgical intervention)
  3. Petechial hemorrhages.

For the purposes of this study, the central clinical endpoint will be time from Last Known Normal to thrombectomy completion. The other data points will be captured for exploratory purposes as correlations and associations with immune cell and cytokine levels may lead to future studies beyond the scope of this grant.

Visit 2 (By and At Discharge) Data collection by Discharge: discharge destination; NIHSS; Mini-Montreal Cognitive Assessment (MiniMoCA) or similar cognitive scale outcome variables. (Standard of Care) Data collection at Discharge: mRS. (Standard of Care)

Visit 3 (90 Day Standard of Care Follow-Up) Data Collection: mRS and Montreal Cognitive Assessment (MoCA). (Standard of Care)

Laboratory Procedures/Evaluations The three biospecimen samples described will be banked, and may be used for pH analysis and electrolyte analysis, serum biomarker analysis, protein and RNA levels, and leukocyte populations. These analyses may be correlated to clinical factors including but not limited to age/gender, interval from Last Known Normal, location of the thrombus, medical co-morbidities, and source of the thrombus.

Condition Acute Ischemic Stroke
Treatment Registry
Clinical Study IdentifierNCT03153683
SponsorJustin Fraser
Last Modified on19 June 2022


Yes No Not Sure

Inclusion Criteria

Patient or the Legally Authorized Representative (LAR) as recognized by the State of Kentucky will be consented for the study within 24 hours post procedure
Male or female, aged 18 years or older
Suspected acute ischemic stroke based on clinical and radiographic evidence as determined and documented by the Stroke Neurology team at University of Kentucky
Participants must meet criteria for intra-arterial thrombectomy as determined and documented by Interventional Radiology attending physician at University of Kentucky
Participants must have an acute thromboembolus within an intracranial artery in the anterior circulation (internal carotid, anterior cerebral, middle cerebral), which undergoes mechanical thrombectomy
Participants with impaired capacity may be included as the pathology to be studied (stroke) may impair their capacity
Participant must undergo thrombectomy procedure
For females of reproductive potential: Negative urine pregnancy test at baseline

Exclusion Criteria

There are no specific exclusion criteria outside of meeting the inclusion criteria
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