Long-term outcomes

Coronary Artery Abnormalities - The Artery Attack

• The most critical long-term complication of Kawasaki Disease, affecting 15-25% of untreated children.
• Timely IVIG therapy dramatically reduces the risk to <5%.
• Pathology involves necrotizing arteritis, destroying the tunica media and internal elastic lamina, leading to aneurysm formation.

• AHA Classification (by Z-score):
  • No involvement: Z-score < 2
  • Dilation only: Z-score 2 to < 2.5
  • Small aneurysm: Z-score ≥ 2.5 to < 5
  • Medium aneurysm: Z-score ≥ 5 to < 10
  • Giant aneurysm: Z-score ≥ 10 or absolute dimension > 8 mm

⭐ Giant aneurysms (>8 mm) have the worst prognosis, with a ~50% risk of thrombosis or stenosis, potentially leading to myocardial infarction.

• Major Long-Term Risks:
  • Stenosis and occlusion from progressive myointimal proliferation.
  • Thrombosis within the aneurysm.
  • Myocardial infarction & sudden death.

Long-Term Management - The Lifelong Lookout

• Goal: Prevent thrombosis & stenosis in affected coronary arteries.

• Risk Stratification is key, based on echocardiography findings during the subacute phase.

• Pharmacotherapy:

  • Low-Dose Aspirin: 3-5 mg/kg/day.
  • Dual Antiplatelet Therapy (DAPT): Aspirin + Clopidogrel, often post-stenting.
  • Anticoagulation: Warfarin (INR 2.0-2.5) or LMWH for giant aneurysms.

⭐ Exam Favourite: The highest risk of myocardial infarction is within the first year after onset, particularly in patients with giant aneurysms.

Adverse Events & Prognosis - The Danger Zone

• Primary Sequela: Coronary Artery Aneurysms (CAA).
  • Can lead to thrombosis, stenosis, & myocardial infarction (MI).
• High-Risk Groups for CAA:
  • Treatment delay >10 days.
  • Age <1 year.
  • Incomplete/atypical presentation.
• Prognosis by Aneurysm Size:
  • Small (<5 mm): High regression rate.
  • Medium (5-8 mm): Variable regression.
  • ⚠️ Giant (>8 mm): Lowest regression; ~50% risk of stenosis/thrombosis.

⭐ The most common cause of death in long-term follow-up is ischemic heart disease/MI from a thrombosed aneurysm.

High‑Yield Points - ⚡ Biggest Takeaways

• Coronary artery aneurysms (CAA) are the most feared long-term complication.
• Risk of CAA is highest in infants <6 months and with delayed IVIG treatment (>10 days).
• Giant aneurysms (>8 mm) carry the worst prognosis, with a high risk of thrombosis or stenosis.
• Lifelong follow-up with echocardiography is mandatory for patients with coronary involvement.
• Patients with giant aneurysms often require lifelong antiplatelet and/or anticoagulant therapy.
• Increased lifetime risk of premature atherosclerotic cardiovascular disease.