What antiplatelet therapy is recommended for patients with spontaneous coronary artery dissection (SCAD), both with and without percutaneous coronary intervention (PCI) and stent placement?

Antiplatelet Therapy for Spontaneous Coronary Artery Dissection (SCAD)

For conservatively managed SCAD without PCI, prescribe aspirin for at least 12 months plus clopidogrel for 1-12 months; for SCAD treated with stent placement, use aspirin plus ticagrelor (or prasugrel) for 12 months followed by aspirin alone. 1, 2, 3

Conservative Management (No PCI/Stent)

Conservative management is the preferred approach for hemodynamically stable SCAD patients with preserved coronary flow, regardless of how severe the dissection appears angiographically. 1, 2, 3

Antiplatelet Regimen for Conservative Management:

• Aspirin: Continue for at least 12 months 1, 2, 3
• Clopidogrel: Continue for 1-12 months after the index event 1, 2, 3
• Avoid potent P2Y12 inhibitors (ticagrelor, prasugrel) in conservatively managed SCAD 4

The rationale for avoiding aggressive dual antiplatelet therapy in conservative SCAD management is critical: DAPT with potent P2Y12 inhibitors has been associated with worse outcomes in conservatively managed SCAD, including higher rates of mortality (4.96% vs 1.55%), major adverse cardiac events (12.13% vs 6.91%), and recurrent SCAD (5.54% vs 2.33%) compared to single antiplatelet therapy. 5 This contrasts sharply with atherosclerotic ACS, where aggressive antiplatelet therapy improves outcomes.

Duration Considerations:

• The exact duration of clopidogrel (1-12 months) should be determined by bleeding risk and clinical stability 1, 2
• After the initial period, transition to aspirin monotherapy 6

SCAD Treated with PCI and Stent Placement

When SCAD requires revascularization with drug-eluting stent placement, treat it as an acute coronary syndrome with standard DAPT. 1, 2

Antiplatelet Regimen for SCAD with Stent:

• Loading doses: Aspirin 150-300 mg plus ticagrelor 180 mg (or prasugrel 60 mg if PCI-naïve) 1
• Maintenance: Aspirin 75-100 mg daily plus ticagrelor 90 mg twice daily for 12 months 1, 2, 3
• After 12 months: Continue aspirin monotherapy indefinitely 1, 2

Switching P2Y12 Inhibitors:

If switching from clopidogrel to ticagrelor (as occurred in the case example), administer a loading dose of 180 mg ticagrelor. 1, 3

Critical Decision Point: To Revascularize or Not

Revascularization by PCI or CABG is indicated only if the patient has ongoing ischemia involving a major coronary territory or recurrent ACS episodes despite maximal medical treatment. 1

Key Considerations Against Routine PCI:

• PCI in stable SCAD has approximately 50% failure rate, even when baseline coronary flow is normal 1, 2, 3
• 13% of stable SCAD patients with normal flow at baseline required emergency CABG following failed PCI 1
• Dissections starting at the ostium or where the true lumen cannot be easily identified carry particularly high risk for abrupt occlusion during PCI 1, 7

If the patient has no pain or ECG changes at the time of angiography and coronary flow is preserved, favor conservative management regardless of angiographic appearance. 1, 2, 3

Medications to Avoid in SCAD

Contraindicated agents that may worsen outcomes:

• Fibrinolytic agents: Can promote hematoma propagation 4, 6
• Anticoagulants: Can favor hematoma expansion 4, 6
• Glycoprotein IIb/IIIa inhibitors: Contraindicated in SCAD 6

Common Pitfalls and How to Avoid Them

Pitfall #1: Treating SCAD Like Atherosclerotic ACS

SCAD is fundamentally different from plaque rupture ACS—the pathophysiology involves intramural hematoma rather than platelet-rich thrombus. 4, 5 Therefore, aggressive antiplatelet therapy may increase bleeding into the dissection plane rather than prevent thrombotic events. Recent observational data shows DAPT is associated with worse outcomes in conservatively managed SCAD compared to single antiplatelet therapy. 5

Pitfall #2: Proceeding to PCI Based on Angiographic Appearance Alone

The angiographic appearance of SCAD can be alarming, but intervention in stable patients carries high failure rates and risk of emergency CABG. 1, 2, 3 Only intervene if there is ongoing ischemia, hemodynamic instability, or recurrent symptoms despite medical therapy. 1

Pitfall #3: Using Intravascular Imaging Indiscriminately

Intravascular ultrasound or OCT should only be used if the decision to revascularize has already been made, as the imaging catheter itself can trigger abrupt vessel closure. 1, 7

Pitfall #4: Forgetting the 12-Month Aspirin Minimum

Even in conservatively managed SCAD, aspirin should be continued for at least 12 months, not just the duration of dual therapy. 1, 2, 3

Special Population Considerations

SCAD affects women in over 90% of cases and is frequently associated with emotional or physical stress as a precipitating factor. 1, 3 Fibromuscular dysplasia is present in up to 72% of SCAD patients. 1, 3

Beta-blockers should be prescribed to prevent SCAD recurrence, though the evidence base is limited and awaiting randomized trial results. 4, 8