What is the treatment for Spontaneous Coronary Artery Dissection (SCAD)?

Spontaneous Coronary Artery Dissection (SCAD): Overview and Management

What is SCAD?

SCAD is a non-atherosclerotic, non-traumatic separation of coronary arterial layers that creates a false lumen with intramural hematoma, causing vessel compression and downstream myocardial ischemia. 1 This condition predominantly affects young to middle-aged women (90.5% of cases), particularly those under 60 years of age, and accounts for 22-35% of acute coronary syndrome cases in this demographic. 1, 2

Key Clinical Features

• Patient demographics: Over 90% are women, average age 52.5 years, with 56.9% being postmenopausal 2
• Presentation: All patients present with myocardial infarction—25.7% with STEMI and 74.3% with NSTEMI 2
• Precipitating factors: Emotional stress in 48.3% and physical stress in 28.1% of cases 2
• Associated conditions: Fibromuscular dysplasia in 62.7-72% of patients, connective tissue disorders in 4.9%, and systemic inflammatory disease in 11.9% 1, 2

Diagnosis

Angiographic Classification

Coronary angiography is the gold standard diagnostic test, revealing three distinct types: 3, 1

• Type 1: Multiple radiolucent lumens or arterial wall contrast staining 3, 1
• Type 2: Long, diffuse, smooth narrowing (most common presentation) 3, 1
• Type 3: Focal stenosis (<20mm) mimicking atherosclerosis 3, 1

Adjunctive Imaging

When diagnosis is uncertain, intracoronary imaging with OCT or IVUS should be performed to confirm intramural hematoma or double lumen. 3, 1 However, use these modalities cautiously as instrumentation can propagate the dissection. 3

Additional diagnostic strategies include: 3

• CT coronary angiography (especially for proximal lesions)
• CT/MRA imaging for extracoronary vascular abnormalities and fibromuscular dysplasia screening
• Repeat coronary angiography at 6-8 weeks if diagnostic uncertainty persists

Acute Management Strategy

Conservative Management (First-Line for Stable Patients)

For clinically stable patients without high-risk anatomy, conservative medical therapy is the recommended approach—routine revascularization should NOT be performed. 3, 1 This represents a critical departure from typical ACS management because:

• Most SCAD cases heal spontaneously without intervention 3, 4
• PCI wires can propagate the dissection 3
• Balloons and stents may extend the hematoma and cause vessel occlusion 3
• CABG onto dissected vessels is technically challenging with up to 30% acute graft closure rates 3

Monitor stable patients as inpatients for 3-5 days to observe for early complications. 3, 1 The median hospital stay is 3.0 days with an overall in-hospital major adverse event rate of 7.3%. 2

Indications for Revascularization

Revascularization may be considered ONLY in the following scenarios: 3, 1

• Hemodynamic instability despite conservative therapy
• Ongoing ischemia that fails to resolve with medical management
• Left main or severe proximal two-vessel dissection with critical flow limitation

When revascularization is necessary: 3, 1

• PCI for focal, accessible lesions with ongoing ischemia
• CABG for left main or multivessel involvement, especially when PCI is technically unfeasible

Critical Pitfall

A single-center retrospective study of 189 SCAD patients showed similar 5-year mortality with revascularization versus conservative care, but a HIGHER rate of emergency/urgent CABG in patients with patent vessels who underwent PCI compared to conservative management. 3 This underscores the harm of routine intervention.

Medical Therapy

Acute Phase Medications

Beta-blockers are strongly recommended as they reduce recurrent SCAD risk (hazard ratio 0.36, p=0.004) and should be initiated immediately. 1, 2 The majority of SCAD patients receive aspirin and beta-blocker therapy at discharge. 2

Antiplatelet therapy recommendations: 5

• Dual antiplatelet therapy (aspirin + clopidogrel) is appropriate for most patients
• Potent P2Y12 inhibitors (ticagrelor, prasugrel) should be avoided
• If stenting was performed, continue DAPT for 12 months
• Aspirin monotherapy may be considered for patients without high-risk angiographic features (thrombus burden, critical stenosis, decreased flow)

Medications to AVOID: 5

• Fibrinolytic agents (can favor hematoma propagation)
• Anticoagulants (can worsen intramural bleeding)

Long-Term Medical Management

Aggressive antihypertensive therapy is essential as hypertension is an independent predictor of recurrent SCAD (hazard ratio 2.46, p=0.011). 1, 2

Beta-blockers should be continued long-term for recurrence prevention. 1, 2

Additional medications for specific indications: 5

• ACE inhibitors, ARBs, mineralocorticoid antagonists, and loop diuretics for heart failure symptoms or LVEF <50%
• Statins may be used for pleiotropic properties despite lack of firm evidence

Long-Term Outcomes and Follow-Up

Prognosis

With median follow-up of 3.1 years, the major adverse cardiac event rate is 19.9%: 2

• Death rate: 1.2%
• Recurrent MI: 16.8%
• Recurrent SCAD: 10.4%
• Stroke/TIA: 1.2%
• Revascularization: 5.8%

Follow-Up Strategy for Recurrent Chest Pain

For new acute ACS symptoms: Urgent evaluation per standard ACS guidelines (ECG, troponin monitoring, imaging). Consider SCAD progression, recurrent SCAD, stenosis, or thrombosis. 3

For new or persistent stable angina: Evaluate with stress imaging (echo, CMR, or nuclear perfusion). If high-risk anatomy or compelling clinical scenario, consider coronary imaging as initial approach. 3

For atypical or nonexertional symptoms: Evaluate for non-cardiac causes and address symptom triggers. Consider healing SCAD, coronary vasospasm, or endothelial dysfunction. 3

Coronary CT angiography should be considered for follow-up in patients with persistent or recurrent symptoms. 1

Special Populations

Postpartum SCAD

SCAD occurs more frequently postpartum (median 13 days after delivery) than during pregnancy, with maternal mortality of 5-10%. 6 Specific considerations include:

• Avoid ergometrine for postpartum bleeding as it causes coronary vasospasm 6
• Use bare metal stents only if stenting required (drug-eluting stents contraindicated) 6
• ACE inhibitors, ARBs, and renin inhibitors are absolutely contraindicated if breastfeeding 6
• Low-dose aspirin (75-100mg daily) is relatively safe 6

Migraine Management in SCAD Patients

Avoid triptans due to vasoconstrictive properties; use CGRP inhibitors with caution. 7 Beta-blockers provide dual benefit for both SCAD recurrence prevention and migraine prophylaxis. 7