Assessing Outcomes of Coil Embolization for Unilateral vs Bilateral Chronic Subdural Hematomas ((COAST))

July 15, 2026 updated by: Jonathan Pace, Lahey Clinic

Assessing Outcomes of Coil Embolization for Unilateral vs Bilateral Chronic Subdural Hematomas: A Randomized Controlled Trial.

This is a pragmatic, prospective, multicenter, randomized controlled trial with intention to treat analysis. In which subjects will receive either unilateral or bilateral middle meningeal artery (MMA) embolization using coils for the treatment of unilateral chronic subdural hematomas (cSDH).

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This study will enroll up to 400 subjects who will be randomized to receive either unilateral or bilateral coil MMA embolization. The study will assess the effect of the procedures on hematoma size and patient functional outcomes over 1 to 3 months of follow-up.

Study Type

Interventional

Enrollment (Estimated)

400

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United States
    • Massachusetts
      • Burlington, Massachusetts, United States, 01803

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

Candidates for this study must meet ALL of the following criteria:

  1. Subject is 18 years of age or older.
  2. Subject has a diagnosis of chronic subdural hematoma with mass effect Determined by brain imaging (CT or MRI) and correlated clinical symptoms.

  3. Pre-randomization modified Rankin Score (mRS) ≤3

    a. Surgical Cohort: Assessment should reflect the subject's condition just prior to undergoing surgery. Assessment may be performed post-surgery using pre-surgical data.

  4. Subdural Hematoma Size

    Medical Management Cohort:

    • Midline shift < 10mm and hematoma thickness > 10 mm as measured on coronal imaging perpendicular to the skull.
    • No focal deficit related to the chronic subdural hematoma requiring surgical intervention

    Surgical Cohort:

    • No requirement

  5. A CT performed prior to randomization demonstrating stability of the hematoma. Stability is defined as no worsening of midline shift or increase in the size of the cSDH from the screening image that results in new or worsening clinical symptoms.
  6. Patient or designated Legal Authorized Representative, confirms the patient has the mental capacity, willingness and ability to comply with protocol and follow-up requirements
  7. In the opinion of the treating physician, MMA embolization is technically feasible, including evaluation of preoperative CTA, if available, or presence of a foramen spinosum bilaterally.

Exclusion Criteria:

  • Candidates will be excluded from participation if ANY of the following apply:

    1. Patients presenting with an acute SDH (e.g. patient with presenting with a SDH due to trauma); mixed density is permitted.
    2. Subject presents with bilateral cSDHs requiring treatment (contralateral cSDH <5mm and not requiring treatment is permitted.
    3. Subject presents with Glasgow Coma Scale < 9
    4. Markwalder assessment >4
    5. cSDH that developed with underlying conditions such as vascular lesions, brain tumor, arachnoid cyst, spontaneous intracranial hypotension, end stage renal disease (ESRD) on hemodialysis, end stage liver disease or other comorbidities causing a coagulopathy
    6. Prior carotid stent placement that crosses the origin of the External Carotid Artery (ECA) ipsilateral to the subdural hematoma
    7. Presumed septic embolus, or suspicion of microbial superinfection
    8. CT or MRI evidence of intra-cranial tumor or mass lesion
    9. Significant contraindication to angiography (eg. kidney failure).
    10. Life expectancy of less than 1-year
    11. Women who are pregnant, lactating, plan on becoming pregnant during the course of the clinical investigation. We routinely do pregnancy tests prior to this procedure, to avoid radiation exposure to the fetus including radiation on follow up CT scans
    12. Current involvement in an investigational (drug, device, etc.) clinical trial that may confound study endpoints. Subjects in observational, natural history, and/or epidemiological studies not involving intervention are eligible
    13. Patient unwilling to follow SOC recommendations (e.g. refuses surgery or lifestyle modifications)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Medical Management
In this cohort, subjects will undergo either unilateral or bilateral middle meningeal artery (MMA) embolization using coils as part of their medical management for chronic subdural hematoma (cSDH). In the unilateral arm, the MMA on the side of the hematoma is embolized, while in the bilateral arm, both sides are embolized regardless of hematoma location.
Device: embolization therapy Bilateral
In the bilateral approach, both middle meningeal arteries are accessed and embolized using coils, regardless of hematoma location. Imaging guidance is used throughout the procedure to ensure proper coil placement, and post-procedure imaging confirms that both vessels are fully occluded.
Device: embolization therapy Unilateral
In the unilateral approach, the middle meningeal artery (MMA) on the side of the hematoma is accessed via a catheter and occluded using coils under imaging guidance. The procedure targets only the affected side, and follow-up imaging is used to confirm successful embolization and vessel occlusion.
Active Comparator: Surgical
In this cohort, subjects will undergo either unilateral or bilateral middle meningeal artery (MMA) embolization using coils in addition to standard surgical management for chronic subdural hematoma (cSDH). In the unilateral arm, the MMA on the side of the hematoma is embolized, while in the bilateral arm, both sides are embolized regardless of hematoma location.
Device: embolization therapy Bilateral
In the bilateral approach, both middle meningeal arteries are accessed and embolized using coils, regardless of hematoma location. Imaging guidance is used throughout the procedure to ensure proper coil placement, and post-procedure imaging confirms that both vessels are fully occluded.
Device: embolization therapy Unilateral
In the unilateral approach, the middle meningeal artery (MMA) on the side of the hematoma is accessed via a catheter and occluded using coils under imaging guidance. The procedure targets only the affected side, and follow-up imaging is used to confirm successful embolization and vessel occlusion.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in cSDH Maximum thickness From Baseline on Non-contrast Head CT
Time Frame: Baseline, 1 month (3-6 weeks), and 3 months (10-14 weeks)
Change in maximum hematoma thickness (mm) and Volume (mL) measured on non-contrast head CT compared with baseline. Measurements will be performed using standardized imaging review.
Baseline, 1 month (3-6 weeks), and 3 months (10-14 weeks)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of Participants Requiring Additional surgical Intervention
Time Frame: Through 3 months
Number of participants requiring additional surgical treatment after randomization, including initial surgical evacuation in the medical management cohort or repeat hematoma evacuation in the surgical cohort.
Through 3 months
Change from Baseline in Modified Rankin scale (mRS) Score
Time Frame: Baseline, 1 month, and 3 months
Functional outcome measured using the Modified Rankin Scale (range 0-6). change from baseline will be reported.
Baseline, 1 month, and 3 months
Number of participants with Procedure-related Serious Adverse Events
Time Frame: through 3 months after embolization
Number of participants experiencing procedure related adverse events, including but not limited to ischemic stroke, intracranial hemorrhage, arterial dissection, vessel perforation, access-site complications requiring intervention, or death.
through 3 months after embolization

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Lahey Clinic

Investigators

  • Principal Investigator: Jonathan Pace, MD, Lahey Hospital & Medical Center

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 9, 2025

Primary Completion (Estimated)

April 30, 2027

Study Completion (Estimated)

June 30, 2027

Study Registration Dates

First Submitted

May 22, 2026

First Submitted That Met QC Criteria

July 15, 2026

First Posted (Actual)

July 20, 2026

Study Record Updates

Last Update Posted (Actual)

July 20, 2026

Last Update Submitted That Met QC Criteria

July 15, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 20253018

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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