BACKGROUND Chronic subdural hematoma (CSDH) is one of the most frequent reasons for cranial neurosurgical consult. There is no widely accepted medical treatment for CSDH.

This trial will investigate whether Tranexamic Acid (TXA) can increase the rate of CSDH resolution following conservative management, lower the number of required surgical procedures and decrease the rate of CSDH recurrence following surgical evacuation. TRACS is a double blind, randomized, parallel-design, placebo-controlled, phase IIB study designed to provide preliminary efficacy data as well as feasibility, safety and incidence data required to plan a larger definitive phase III trial.

METHODS Consecutive patients presenting at the Centre Hospitalier Universitaire de Sherbrooke with a recent (< 14 days) diagnosis of subdural hematoma with a chronic component will be screened for eligibility. Exclusion criteria include specific risk factors for thromboembolic disease, anticoagulant use or contraindication to TXA. A total of 130 patients will be randomized to receive either 750 mg of TXA daily or placebo until complete radiological resolution of the CSDH or for a maximum of 20 weeks. CSDH volume will be measured on serial CT scanning. Cognitive function tests, quality of life questionnaires as well as functional autonomy assessments will be performed at enrollment, 10 weeks follow-up and 3 months post-treatment follow-up. During the treatment period, patients will undergo standard CSDH management with surgery being performed at the discretion of the treating physician. If surgery is performed, the CSDH and its outer membrane will be sampled for in vitro analysis.

The primary outcome is the rate of CSDH resolution at 20 weeks without intervening unplanned surgical procedure. Secondary outcomes include CSDH volume, incidence of surgical evacuation procedures, CSDH recurrence, cognitive functions, functional autonomy, quality of life, incidence of complications and length of hospital stay. Planned subgroup analyses will be performed for conservatively vs surgically-managed subjects and highly vs poorly vascularised CSDH.

DISCUSSION CSDH is a frequent and morbid condition for which an effective medical treatment has yet to be discovered. The TRACS trial will be the first prospective study of TXA for CSDH.

Inclusion Criteria:

• CT scan demonstrating the existence of a subdural hematoma containing a chronic component
• Diagnosis within the last 14 days

Exclusion Criteria:

• Acute subdural hematoma with no chronic component;
• Active thrombotic, thromboembolic or atheroembolic disease, including deep venous thrombosis within the last six months, cerebral thrombosis within the last six months, symptomatic carotid stenosis who did not undergo surgery or stroke within the last year;
• Past history of unprovoked deep venous thrombosis or idiopathic pulmonary embolism;
• Known hereditary thrombophilia, including Factor V Leiden, Antithrombin III mutation, Protein C deficiency, Protein S deficiency;
• Atrial fibrillation (unless under successful rhythm control therapy);
• Metallic heart valve;
• Vascular stenting procedure within the last year;
• Cardiac or vascular surgical procedure within the last 6 months, including endarterectomy, bypass or angioplasty;
• Ongoing investigation for suspected malignancy;
• Confirmed active malignancy;
• Concomitant hormone therapy for malignancy;
• Concomitant hormone contraceptive pill;
• Macroscopic hematuria;
• Known or suspected tranexamic acid allergy;
• Pregnancy or breastfeeding;
• Concomitant use of anticoagulant medication;
• Any concern from the attending physician.