Coronary artery dissection is a spontaneous, non-traumatic, non-atherosclerotic, and infrequent cause of acute MI, responsible for 0.1-4% of cases of ACS.¹ It tends to be more common in younger women, accounting for nearly 25% of cases of ACS in women ≤50 years old.²

Risk factors (seen in 80% of cases)

• Fibromuscular dysplasia (FMD).
• Postpartum status.
• Multiparity (≥4 births).
• Connective tissue disorders e.g. Marfan or vascular Ehlers-Danlos syndrome.
• Systemic inflammatory conditions.
• Hormonal therapy.
• Idiopathic (20%).

Precipitating stressors (seen in over 50% of cases)

• Intense exercise (28.9%).
• Emotional stress (50%).
• Labor and delivery (2-18%).
• Intense Valsalva-type activities.
• Recreational drug uses.
• Aggressive hormonal therapy.

Clinical presentation

• Spontaneous coronary artery dissection often presents with signs and symptoms of acute MI, e.g. chest pain (96%), dyspnea, nausea/vomiting, diaphoresis, arm, neck, or back pain.
• 25-50% of cases present with STEMI, remainder as NSTEMI.
• <1% have no troponin elevation.

• Consider in young patients, especially women, who do not have CAD risk factors but present with symptoms of acute MI or cardiac arrest.
• Coronary angiography is required to confirm the diagnosis.
• The stereotypical presence of a non-iatrogenic dissection plane in the absence of coronary atherosclerosis is seen in <30% of cases.³
• Most of the cases have an appearance of diffuse narrowing due to intramural hematoma.

The coronary angiographic appearance of spontaneous coronary artery dissection has been classified into three types:⁴

• Type 1: Pathognomonic multiple coronary artery wall lumen stained by contrast dye.
• Type 2: Diffuse, long, smooth stenosis (mild to complete occlusion).
• Type 3: Mimics atherosclerosis with focal or tubular stenosis. Requires optical coherence tomography (OCT) or intravascular ultrasound (IVUS) to differentiate the cause.

For cases where coronary angiography cannot help secure the diagnosis, OCT or IVUS can be helpful. Alternatively, repeat coronary angiography in 4-6 weeks can help show spontaneous angiographic healing of the dissected segment, as a way of confirming the diagnosis.

CT angiography is not first-line imaging for confirming coronary artery dissection as it can miss a substantial proportion of the cases.⁵

Prior to diagnosis treat as per usual ACS treatment:

• Early ASA,
• Plavix/ticagrelor,
• heparin, and
• supportive treatment as needed (e.g. nitroglycerin, anti-emetics).
• Rarely, treatments for acute heart failure or arrhythmias are required.
• For patients with cardiogenic shock inotropes, intubation, ventilation, and ECMO may be required as a bridge to more definitive care.

Once the diagnosis is made:

• conservative therapy is the preferred strategy unless there is ongoing ischemia, hemodynamic instability, or left main dissection.⁶
• long-term aspirin.
• beta blocker.
• short-term clopidogrel.
• statin in patients with dyslipidemia.³

Revascularization with PCI or CABG should be considered for patients with ongoing symptoms of MI or hemodynamic compromise.³ However, PCI is technically challenging.

Cardiac rehabilitation program – there are specific exercise recommendations for these patients compared to standard MI patients, e.g. SBP <130mmHg during exercise, HR 50-70% of HR reserve. Women are recommended to avoid lifting weights >20-30 pounds and men >50 pounds.

Prognosis

In-hospital prognosis is generally good for patients managed either conservatively or with CABG, while the short-term outcome for those managed with PCI is less favorable.³ Acute PCI success is seen in less than 50-70% of cases, and long-term success without complication in 30% of cases.³

Recurrent cardiovascular events frequent following an initial even:

• Repeat coronary dissection may occur in 13-17% of patients with long-term follow-up.
• In-hospital mortality rate is 4.2%.
• Recurrent in-hospital MI rate is 4.6%, with unplanned revascularization in 4.3%.⁷
• Estimated 10-year rate of death, heart failure, myocardial infarction, or dissection recurrence is 47%.⁸

Disposition

1. Cardiac catheterization lab or operating room – for patients with ongoing MI symptoms, STEMI, or hemodynamic compromise, requiring PCI or CABG.
2. Cardiac inpatient service – for patients confirmed or suspected to have a coronary artery dissection and requiring medical management.

1. Nishiguchi T, Tanaka A, Ozaki Y, et al. Prevalence of spontaneous coronary artery dissection in patients with acute coronary syndrome. Eur Heart J Acute Cardiovasc Care 2016; 5:263.

   
   

2. Saw J, Aymong E, Mancini GB, et al. Nonatherosclerotic coronary artery disease in young women. Can J Cardiol 2014; 30:814.

   
   

3. Saw J, Aymong E, Sedlak T, et al. Spontaneous coronary artery dissection: association with predisposing arteriopathies and precipitating stressors and cardiovascular outcomes. Circ Cardiovasc Interv 2014; 7:645.

   
   

4. Saw J. Coronary angiogram classification of spontaneous coronary artery dissection. Catheter Cardiovasc Interv 2014; 84:1115.

   
   

5. Tweet MS, Akhtar NJ, Hayes SN, et al. Spontaneous coronary artery dissection: Acute findings on coronary computed tomography angiography. Eur Heart J Acute Cardiovasc Care 2019; 8:467.

   
   

6. Hayes SN, Kim ES, Saw J, Adlam D, Arslanian-Engoren C, Economy KE, et al. Spontaneous coronary artery dissection: current state of the science: a scientific statement from the American Heart Association. Circulation. 2018 May 8;137(19):e523-57.

   
   

7. Krittanawong C, Kumar A, Virk HUH, et al. Trends in Incidence, Characteristics, and In-Hospital Outcomes of Patients Presenting With Spontaneous Coronary Artery Dissection (From a National Population-Based Cohort Study Between 2004 and 2015). Am J Cardiol 2018; 122:1617.

   
   

8. Tweet MS, Hayes SN, Pitta SR, et al. Clinical features, management, and prognosis of spontaneous coronary artery dissection. Circulation 2012; 126:579.