What causes coronary artery dissection?

Causes of Spontaneous Coronary Artery Dissection (SCAD)

Spontaneous coronary artery dissection is predominantly caused by a combination of predisposing arteriopathies and precipitating stressors, with the highest prevalence in young women, particularly during the peripartum period. 1

Primary Causes and Mechanisms

• SCAD is defined as a non-atherosclerotic, non-traumatic separation of coronary arterial layers creating a false lumen and intramural hematoma that compresses the true lumen, leading to downstream myocardial ischemia 2
• The pathophysiological mechanism involves spontaneous formation of an intramural hematoma within the coronary artery wall, with or without an intimal tear 1
• SCAD accounts for up to 4% of all acute coronary syndromes but represents 20-35% of acute coronary syndromes in women under 60 years of age 1

Predisposing Conditions and Risk Factors

Arteriopathies and Connective Tissue Disorders

• Fibromuscular dysplasia (FMD) is present in up to 72% of SCAD patients and represents the strongest association with SCAD 3, 2
• Connective tissue disorders including systemic lupus erythematosus, Marfan syndrome, and other genetic arteriopathies predispose to weakened arterial walls 1, 4
• Genetic factors play a role, with up to 10% of patients harboring rare variants with large effects, while most cases have a complex genetic architecture 5, 6

Hormonal Influences

• Pregnancy and the peripartum period represent significant risk factors, with SCAD being particularly prevalent during this time 1, 7
• Hormonal fluctuations may contribute to arterial wall weakening, especially in women 1

Other Associated Conditions

• Systemic inflammatory diseases can weaken arterial walls and predispose to SCAD 4
• Anxiety, depression, and previous neuropsychiatric disorders have higher prevalence in SCAD patients 3

Precipitating Factors

• Intense emotional stress can trigger SCAD in predisposed individuals 3, 2
• Physical stressors including intense exercise, Valsalva-type activities, or labor and delivery can precipitate SCAD 1, 3
• Hypertension is an independent predictor of recurrent SCAD 3, 2

Demographic Patterns

• Over 90% of SCAD cases occur in women 2
• The condition disproportionately affects young to middle-aged women without traditional cardiovascular risk factors 1, 7
• SCAD has a distinct genetic risk profile that is actually inversely related to atherosclerotic coronary artery disease 6

Clinical Considerations

• SCAD should be suspected in any young woman presenting with acute coronary syndrome without traditional risk factors 1
• Diagnosis is confirmed by coronary angiography, potentially supplemented by intracoronary imaging (OCT or IVUS) 2
• SCAD has a high recurrence rate, with subsequent events often occurring in different coronary arteries 8

Management Implications

• Conservative management is preferred for stable patients, as revascularization attempts can worsen dissections 2
• Beta-blockers are strongly recommended for long-term management as they reduce recurrence risk 3, 2
• Aggressive blood pressure control is essential as hypertension increases recurrence risk 3, 2

Understanding these causes is crucial for proper diagnosis, management, and prevention of recurrence in patients with SCAD, particularly given its distinct pathophysiology compared to atherosclerotic coronary disease.