Imaging Collaterals in Acute Stroke (iCAS)

Completed

• Conditions: Stroke, Acute

• Registration Number: NCT02225730
• Lead Sponsor: Stanford University

Brief Summary

Stroke is caused by a sudden blockage of a blood vessel that delivers blood to the brain. Unblocking the blood vessel with a blood clot removal device restores blood flow and if done quickly may prevent the disability that can be caused by a stroke.

However, not all stroke patients benefit from having their blood vessel unblocked.

The aim of this study is to determine if special brain imaging, called MRI, can be used to identify which stroke patients are most likely to benefit from attempts to unblock their blood vessel with a special blood clot removal device. In particular, we will assess in this trial whether a noncontrast MR imaging sequence, arterial spin labeling (ASL), can demonstrate the presence of collateral blood flow (compared with a gold standard of the angiogram) and whether it is useful to predict who will benefit from treatment.

Detailed Description

Intravenous tissue plasminogen activator (IV tPA) is the standard of care treatment for stroke patients when treatment can be initiated within 3 hours after symptom onset. Unfortunately, only a very small fraction of stroke patients is treated with tPA, and benefits from tPA. This is the result of two main limitations of tPA therapy.

First, the proportion of patients that can be treated with iv tPA is small. Because of the narrow three hour time-window during which tPA is effective, only patients who arrive to the hospital early on can be treated with tPA. Most stroke patients, however, arrive at the hospital after the three-hour time-window and are therefore excluded from tPA treatment. Second, stroke patients who receive tPA do not always benefit because the treatment does not restore blood flow in all patients.

Patients with persistent blood vessel occlusions and no improvement in their clinical condition after receiving tPA or those arriving at the hospital outside the 3 hour time window routinely undergo mechanical clot removal to open an occluded blood vessel in the brain.

Mechanical clot removal increases the percentage of stroke patients who achieve recanalization, and as a result may increase the proportion of patients who have good clinical outcomes. However it is unclear for which stroke patients mechanical thrombectomy is most suitable. Although effective at removing blood-clots, it appears that mechanical clot retrieval is not beneficial for all patients. Whereas some patients benefit, others experience no effect, and yet others are likely harmed by mechanical clot retrieval. In order to avoid harm and maximize benefit it is important to know, prior to initiation of the mechanical clot retrieval procedure, if the procedure is likely to result in a clinical improvement. We hypothesize that the response to mechanical clot retrieval can be predicted based on characteristics of an MRI scan obtained just prior to the retrieval procedure. In particular, this study will assess whether a new non-contrast MR imaging method, arterial spin labeling (ASL), which measures cerebral blood flow and can give insight into collateral flow, is effective at predicting who will benefit most from treatment. The investigators hope to learn if these new MRI techniques can help identify which patients are most likely to benefit from mechanical clot removal after receiving tPA.

Study Timeline

• Study Start: 2013-09
• Study First Submitted: 2014-08-22
• Study First Submitted QC: 2014-08-22
• Study First Posted: 2014-08-26
• Primary Completion: 2019-10-31
• Study Completion: 2019-10-31
• Status Verified: 2020-03
• Last Update Submitted: 2020-03-17
• Last Update Posted: 2020-03-19

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 187

Inclusion Criteria

Not provided

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Exclusion Criteria

Not provided

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Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
favorable clinical response	day 30	A "favorable clinical response", defined as an 8-point or more improvement on the NIH score when comparing the baseline score to the 30-day score or NIH score of 0 or a 30-day NIH score of 0-1

Secondary Outcome Measures

Name	Time	Method
modified Rankin Score	day 90	90 day modified Rankin Score 5-6 and 90 day modified Rankin distribution

Trial Locations

Locations (4)

Stanford University Medical Center; 🇺🇸 Stanford, California, United States

Swedish Hospital; 🇺🇸 Seattle, Washington, United States

University of Pittsburgh; 🇺🇸 Pittsburgh, Pennsylvania, United States

Eden Medical Center; 🇺🇸 Castro Valley, California, United States