CAD

Spontaneous Coronary Artery Dissection

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Spontaneous Coronary Artery Dissection, SCAD

  • Definitions
  1. Spontaneous Coronary Artery Dissection (SCAD)
    1. Epicardial Coronary Artery dissection not due to atherosclerosis, Trauma or procedure
  • Epidemiology
  1. Identified in up to 4% of angiograms performed for Acute Coronary Syndrome
  2. Women account for >85% of SCAD cases
  3. More common in young women (esp. ages 45 to 53 years old)
  4. Accounts for up to 35-40% of Myocardial Infarctions in women age <50 years old
  5. Most common cause of Myocardial Infarction in pregnancy (esp. first 4 weeks after delivery)
    1. Pregnancy accounts for 8% of all SCAD cases
  • Pathophysiology
  1. Distribution
    1. Left Anterior Descending Artery is most commonly involved (but any Coronary Artery may be involved)
  2. Myocardial injury mechanism
    1. Coronary Artery forms intramural Hematoma or intimal disruption resulting in Coronary Artery obstruction
  • Risk Factors
  1. Lacks typical atherosclerosis related risk factors
  2. Women
  3. Pregnancy
  4. Multiparity (>4 births)
  5. Fibromuscular dysplasia
  6. Exogenous Hormones (Estrogens, Testosterone, Corticosteroids, Clomiphene, bHCG injection)
  7. Inherited Connective Tissue Disease
    1. Marfan Syndrome
    2. Loeys-Dietz Syndrome
    3. Vascular Ehlers-Danlos Syndrome
    4. Alpha-1-Antitrypsin Deficiency
    5. Polycystic Kidney Disease
  8. Systemic Inflammatory Disease
    1. Systemic Lupus Erythematosus
    2. Crohn Disease
    3. Ulcerative Colitis
    4. Polyarteritis Nodosa
    5. Sarcoidosis
    6. Churg-Strauss Syndrome
    7. Granulomatosis with Polyangiitis
    8. Rheumatoid Arthritis
    9. Kawasaki Disease
    10. Celiac Disease
  • History
  • Provocative Factors (present in >50% of cases)
  1. Intense Exercise
  2. Strong Valsalva Maneuver
  3. Retching or forceful Vomiting
  4. Straining at the stool
  5. Forceful coughing
  6. Heavy Lifting
  7. Severe emotional stress
  8. Labor and Delivery
  9. Stimulants (e.g. Cocaine, Methamphetamine)
  • Findings
  1. See Acute Coronary Syndrome
  2. Nearly identical presentation to typical Acute Coronary Syndrome
    1. Chest Pain
    2. EKG with findings consistent with ST Elevation Myocardial Infarction (STEMI)
    3. Serum Troponin elevation
  • Imaging
  1. Coronary Angiography
    1. Most cases are diagnosed during Coronary Angiography
  2. Intracoronary Imaging (intravascular Ultrasound)
  3. Coronary Computed Tomography Angiography (CCTA)
  • Management
  1. See Acute Coronary Syndrome
  2. Background
    1. Angiographic lesion healing occurs in >70% of patients within weeks to months
    2. Conservative therapy is therefore preferred in stable without high risk lesions
  3. Precautions
    1. Avoid Thrombolytics (e.g. TPA)
    2. Consider SCAD in young women with STEMI, without traditional CAD risk factors
      1. Discuss with interventionist on transfer to Coronary Angiography
  4. Unstable (Active, persistent ischemia or hemodynamic instability)
    1. Percutaneous Coronary Intervention (PCI) OR
    2. Urgent Coronary Artery Bypass Graft (CABG)
  5. High Risk Anatomy (Clinically stable with left main dissection or severe proximal two vessel dissection)
    1. Consider for Coronary Artery Bypass Graft (CABG)
  6. Clinically stable AND no high risk anatomy: Conservative Therapy
    1. Dual Antiplatelet Therapy
      1. Duration: 3-12 months
      2. When dual therapy completed, continue Aspirin daily
    2. Beta Blockers
      1. Indicated in Left Ventricular Dysfunction, Arrhythmia
    3. ACE Inhibitors (or Angiotensin Receptor Blockers)
      1. Indicated in Left Ventricular Systolic Dysfunction
    4. Other therapies that are typically not indicated in SCAD (contrast with coronary atherosclerosis)
      1. Routine Statin use is not indicated
      2. Routine Nitroglycerin or Antianginals are not indicated
  • Complications
  1. Acute Coronary Syndrome
  2. Myocardial Infarction
  • References
  1. Carr and Swaminathan in Herbert (2021) EM:Rap 21(4): 2-3
  2. Hayes (2020) Circulation 19:e523-57 +PMID:29472380 [PubMed]
    1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5957087/