What is the management and treatment approach for a patient presenting with Spontaneous Coronary Artery Dissection (SCAD)?

Management of Spontaneous Coronary Artery Dissection (SCAD)

Conservative medical management should be the preferred initial strategy for clinically stable SCAD patients, as revascularization is associated with high procedural failure rates (53%) and does not reduce target vessel revascularization or recurrent SCAD compared to conservative therapy. 1, 2

Initial Diagnostic Confirmation

• Coronary angiography is the primary diagnostic tool, identifying three distinct angiographic types 1:

  • Type 1: Contrast dye staining with multiple radiolucent lumens 1
  • Type 2: Long diffuse smooth narrowing (can be obstructive >50% or non-obstructive <50%) 1
  • Type 3: Focal stenosis mimicking atherosclerosis 1

• Intracoronary imaging with OCT or IVUS should be used in unclear cases to confirm intramural hematoma or double lumen, as this is fundamental to proper diagnosis 1, 3

• CCTA may miss SCAD, so a negative CCTA should not exclude the diagnosis 1

Risk Stratification: Who Needs Revascularization?

Reserve revascularization only for:

• Hemodynamic instability (cardiogenic shock, sustained ventricular arrhythmias) 3
• Left main dissection with critical flow limitation 3, 4
• Proximal two-vessel dissection with critical flow limitation 3, 4
• Ongoing ischemia despite medical therapy with vessel occlusion 1

A critical pitfall: Even patients with preserved vessel flow have 50% PCI failure rates, and 13% require emergency CABG when PCI is attempted 2. This underscores why conservative management is preferred for stable patients.

Conservative Management Protocol

For clinically stable patients (the majority):

• Inpatient monitoring for 3-5 days to observe for early complications, as 10% experience early SCAD progression requiring revascularization 3, 2
• 90% of conservatively managed patients have an uneventful in-hospital course 2
• Serial cardiac biomarkers and ECGs to detect progression 5
• Repeat angiography only if clinical deterioration occurs 4, 2

Medical Therapy: The Cornerstone of Treatment

Beta-blockers are strongly recommended as they are significantly associated with reduced risk of recurrent SCAD 1, 3

Aggressive anti-hypertensive therapy is essential because hypertension is an independent predictor of recurrent SCAD 1, 3

• Target blood pressure <130/80 mmHg 6
• Beta-blockers serve dual purpose: blood pressure control and SCAD recurrence prevention 1, 3

Antiplatelet therapy considerations:

• Low-dose aspirin (75-100 mg daily) is reasonable 4
• Clopidogrel should only be used when strictly necessary (e.g., after stenting) and for the shortest duration possible 4

Revascularization: When Absolutely Necessary

If revascularization cannot be avoided:

• PCI for focal, accessible lesions with ongoing ischemia, but expect 53% procedural failure rate 3, 2
• CABG for left main or multivessel involvement, especially when PCI is technically challenging 3, 4
• Bare metal stents only in postpartum patients due to unknown safety profile of drug-eluting stents and requirement for prolonged dual antiplatelet therapy 4

Critical caveat: PCI failure rates remain high (50-53%) even with preserved vessel flow, and emergency CABG may be required in 13% of attempted PCI cases 2

Special Population: Postpartum SCAD

• SCAD occurs more frequently postpartum (median 13 days after delivery) than during pregnancy 4
• Avoid ergometrine for postpartum bleeding as it causes coronary vasospasm and worsens ischemia 4
• ACE inhibitors and ARBs are contraindicated if breastfeeding 4
• Maternal mortality is 5-10% and highest during the peripartum period 4

Long-Term Management and Surveillance

Continue beta-blocker therapy indefinitely to prevent recurrence 3

Monitor for recurrent SCAD:

• 5-year recurrence rate is 23-31% regardless of initial management strategy 2
• Chest discomfort is the most frequent presenting symptom (96% of cases) 5
• One-third of patients have unstable symptoms at presentation requiring urgent evaluation 5

Follow-up imaging:

• CCTA for persistent or recurrent symptoms 3
• Repeat angiography only if clinical deterioration or evidence of ischemia 6

High-Risk Demographics to Recognize

• Women account for 90-92% of SCAD cases 3, 2, 5
• SCAD represents 8.7-10.8% of ACS in women <50 years old 7
• Associated conditions: fibromuscular dysplasia, anxiety, depression, neuropsychiatric disorders 1
• Pregnancy-related MI: SCAD accounts for 22-35% of cases 1

Outcomes: Conservative vs. Revascularization

No difference in 5-year outcomes between strategies 2:

• Target vessel revascularization: 30% (revascularization) vs. 19% (conservative), P=0.06 2
• Recurrent SCAD: 23% (revascularization) vs. 31% (conservative), P=0.7 2
• 77% of patients are event-free at 1 year regardless of strategy 7