In a patient with coronary artery disease status post coronary artery bypass grafting who develops an acute subdural hematoma, how should antiplatelet therapy be managed and when can it be safely restarted?

Management of Antiplatelet Therapy in Acute Subdural Hematoma Post-CABG

All antiplatelet agents must be discontinued immediately upon diagnosis of acute subdural hematoma and held for at least 1-2 weeks during the acute hemorrhagic period, regardless of cardiac history. 1

Immediate Management (Acute Phase)

Discontinuation Protocol

• Stop all antiplatelet therapy immediately upon SDH diagnosis, including both aspirin and any P2Y12 inhibitors (clopidogrel, ticagrelor, prasugrel) 1
• The acute bleeding risk from intracranial hemorrhage supersedes the thrombotic risk from stopping antiplatelet therapy, even in post-CABG patients 1
• Platelet transfusions may be considered if the patient received clopidogrel within 5 days, as the drug inhibits platelets for their 7-10 day lifespan 2
• However, platelet transfusions are less effective if given within 4 hours of a loading dose or 2 hours of maintenance dosing 2

Duration of Withholding

• Maintain complete cessation of all antiplatelet agents for a minimum of 1-2 weeks after the acute hemorrhage 1
• This period allows for initial hematoma stabilization and reduces rebleeding risk 1
• Serial neuroimaging should guide the duration of withholding beyond 2 weeks based on hematoma evolution 1

Risk Stratification for Restart (After 2+ Weeks)

High Cardiac Risk Indicators (Favor Earlier Restart)

• CABG performed within the past 12 months 1
• History of recent ACS (within 1 year) that prompted the CABG 1
• Poor graft targets or incomplete revascularization 1
• Recurrent anginal symptoms during the antiplatelet-free period 1

High Bleeding Risk Indicators (Favor Delayed Restart)

• Large SDH volume or mass effect on imaging 1
• Lobar location suggesting possible cerebral amyloid angiopathy 1
• Presence of microbleeds on gradient echo MRI sequences 1
• Age >75 years 1
• Uncontrolled hypertension 1

Restart Strategy (After Acute Phase)

Timing Considerations

• For stable post-CABG patients without recent ACS: Consider restarting aspirin monotherapy at 3-4 weeks if neuroimaging shows stable or resolving hematoma 1
• For post-CABG patients with recent ACS history: Cardiology and neurosurgery consultation is mandatory to weigh competing risks 3
• The 2024 ESC guidelines emphasize that aspirin should be restarted "as soon as there is no concern over bleeding" post-CABG, but this must be balanced against intracranial hemorrhage risk 1

Medication Selection

• Start with aspirin monotherapy (75-100 mg daily) as the first agent to restart 1
• Aspirin provides baseline antiplatelet protection with lower bleeding risk than dual therapy 1
• Avoid restarting P2Y12 inhibitors (clopidogrel, ticagrelor) unless there is a compelling recent ACS indication (within past year) 1
• The 2018 ESC guidelines explicitly state there is no convincing evidence for DAPT in the postoperative phase after CABG to prevent graft failure in stable CAD patients 1

Dual Antiplatelet Therapy Considerations

• DAPT after CABG is only indicated if the patient had ACS within the past 12 months, not for stable CAD post-CABG 1
• If DAPT is deemed absolutely necessary due to very recent ACS: Wait minimum 4 weeks post-SDH, obtain repeat neuroimaging showing stability, and use clopidogrel (not ticagrelor/prasugrel) as it has lower bleeding risk 1, 3
• When restarting clopidogrel post-SDH, do not use a loading dose—start with maintenance dose of 75 mg daily 1

Monitoring After Restart

Clinical Surveillance

• Repeat brain imaging 2-4 weeks after restarting antiplatelet therapy to assess for rebleeding 1
• Monitor closely for neurological symptoms suggesting hemorrhage expansion 1
• Assess for recurrent anginal symptoms that might indicate graft occlusion 1

Long-term Management

• Aspirin monotherapy (75-100 mg daily) should be continued indefinitely in post-CABG patients once safely restarted 1
• Rigorous blood pressure control is essential, as uncontrolled hypertension contributed to bleeding in documented cases 1
• Consider proton pump inhibitor co-therapy to reduce GI bleeding risk from chronic aspirin use 1

Critical Pitfalls to Avoid

• Never restart antiplatelet therapy before 2 weeks post-SDH, even in high-risk cardiac patients—the rebleeding risk is prohibitive 1
• Do not assume post-CABG patients automatically need DAPT—this is only true for recent ACS, not stable CAD 1
• Avoid using ticagrelor or prasugrel when restarting therapy post-hemorrhage, as these potent P2Y12 inhibitors carry higher bleeding risk than clopidogrel 1, 3
• Do not restart both agents simultaneously—begin with aspirin alone and add P2Y12 inhibitor only if absolutely necessary after additional weeks of stability 1, 3
• Avoid omeprazole or esomeprazole if clopidogrel is used, as these significantly reduce clopidogrel's antiplatelet activity via CYP2C19 inhibition 1, 2