Kawasaki Disease or Incomplete Kawasaki Disease Clinical Pathway — Emergency Department and Inpatient

Antiplatelet Therapy

Aspirin has been used in the treatment of KD for its anti-inflammatory activity at high doses (early in the disease) and anti-platelet activity at low doses (for chronic thromboprophylaxis). There is no evidence that aspirin decreases the incidence of coronary artery abnormalities, and there is no data to suggest that a high vs. moderate dose of aspirin is superior. The AHA guidelines state it is reasonable to administer moderate- or high-dose aspirin until the patient is afebrile, although there is no evidence it reduces coronary artery aneurysms.

This pathway does not recommend high-dose aspirin in those already receiving steroids, since steroids offer a powerful anti-inflammatory effect. This pathway suggests transitioning to low-dose ASA after 24 hours to allow for a better assessment of fever and treatment resistance prior to discharge.

Dose
  • Patients not receiving steroids:
    • High dose x 24 hours (80-100 mg/kg/day divided Q 6 hours)
    • Discontinue high-dose ASA after 24 hours and start on low-dose ASA
      (3-10 mg/kg given daily, max 81 mg)
  • Patients receiving steroids:
    • Low-dose ASA (3-10 mg/kg given daily, max 81 mg)
  • Patients with G6PD:
    • Avoid high-dose aspirin and administer low-dose aspirin only
2nd Line Thrombosis Prevention
  • If coronary artery z-score measures ≥ 5, discuss with cardiology about increasing anti-platelet therapy with clopidogrel (Plavix®) in addition to aspirin.
  • If coronary artery z-score measures ≥ 10, discuss with cardiology about the initiation of systemic anticoagulation (LMWH or warfarin). If systemic anticoagulation is started, cardiology should contact the Cardiac Anti-coagulation and Thrombosis Team to help manage these patients.
  • There should be discussions about transferring to a primary cardiology service in the setting of z-scores ≥ 5.
  • For patients with increased risk of thrombosis (large or giant aneurysms and recent history of coronary artery thrombosis), triple therapy with antiplatelet medications, 2nd antiplatelet agent and anticoagulation may be considered.
  • Ibuprofen and other NSAIDs may be harmful in patients taking ASA for its antiplatelet effects and should be avoided.
Special Considerations
  • Avoid ibuprofen or other NSAID (antagonizes anti-platelet effect of aspirin and clopidogrel)
  • Adverse effects (rare): GI bleed, tinnitus, Reye’s syndrome
    • Reye’s syndrome – rare, but increased risk with aspirin and viral infection.
    • Consider inactivated influenza vaccine (avoid live vaccines (e.g., varicella) until off aspirin or discuss risk-benefit when on low-dose aspirin).
    • No cases of Reye’s syndrome have been reported for patients on low-dose ASA according to the latest AHA KD guidelines.
  • Note:
    • There is no evidence that ASA decreases aneurysms or that outcomes are different with low- vs. high-dose ASA.
    • High-dose ASA may help with inflammation initially.
    • Low-dose ASA is necessary for thrombosis prevention and should be continued through discharge, with length of therapy.

Reference

Diagnosis, Treatment, and Long-Term Management of Kawasaki Disease: A Scientific Statement for Health Professionals From the American Heart Association