Kawasaki Disease Coronary & Risk Calculator

Coronary Z-scores, 2024 AHA Risk Stratification, Son & Kobayashi Scores, Antithrombotic Guidelines

AHA 2024 Scientific Statement Update · Circulation 2024

Clinical Decision Support: For use by qualified pediatric cardiologists and physicians. Normal coronary dimensions do not rule out Kawasaki Disease. Treatment should be initiated promptly when KD is suspected.

1. Patient Demographics & BSA

Accurate weight & height are required for Haycock Body Surface Area (BSA) calculation.

Age (years)

Age (months)

Weight (kg)

Height / Length (cm)

Sex

Patient ID / Name (for print report)

2. Coronary Artery Measurements & Z-Scores

Measurements in mm from inner-edge to inner-edge excluding branching points.

Boston (McCrindle 2007): Exponential model with Haycock BSA. Default AHA recommendation. (LCx computed via Dallaire 2011).

LMCA — Left main coronary artery mm

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LAD — Left anterior descending mm

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LCx — Left circumflex mm

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RCA — Right coronary artery mm

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Assessment Timing / Phase

Historical Maximal Coronary Involvement

1. Risk Scoring & Diagnostic Criteria Son 2019 · Kobayashi · AHA 2024

Evaluates risk for Coronary Artery Aneurysms (CAA) and IVIG Resistance to identify candidates for intensified primary anti-inflammatory therapy.

North American Risk Score for CAA (Son et al. 2019 · AHA 2024 Update)

Predicts high risk of coronary artery aneurysms by 8 weeks post-acute illness. Validated in diverse North American cohorts.

Age < 6 months (Auto-checked if age entered <0.5 yr)

+1 pt

Asian race / ancestry

+1 pt

Baseline Coronary Z-score > 2.0 on initial echocardiogram (Auto-checked if max Z > 2.0)

+2 pts

C-reactive protein (CRP) > 13 mg/dL (>130 mg/L)

+1 pt

0 / 5

Standard Risk (Score < 3)

💡 AHA 2024 Clinical Implication: Score ≥ 3 points is strongly predictive of CAA. High-risk patients should be considered for intensification of primary therapy (IVIG + Infliximab 10 mg/kg OR IVIG + Prednisolone).

Japanese Kobayashi Risk Score (IVIG Resistance Prediction · RAISE / KAICA)

Predicts non-response to standard initial IVIG infusion. Score ≥ 4 (or ≥ 5) indicates high risk of IVIG resistance and CAA.

Serum Sodium ≤ 133 mmol/L (mEq/L)

+1 pt

Days of illness at diagnosis ≤ 4 days

+2 pts

AST (SGOT) ≥ 100 U/L

+2 pts

% Neutrophils ≥ 80%

+2 pts

CRP ≥ 10 mg/dL (≥ 100 mg/L)

+1 pt

Age ≤ 12 months (Auto-checked if age entered ≤1.0 yr)

+1 pt

Platelet count ≤ 300,000 /mm³ (≤ 300 × 10⁹/L)

+1 pt

0 / 10

Low Risk for IVIG Resistance (< 4 pts)

2024 AHA Diagnostic Algorithm: Complete vs. Incomplete KD

Complete KD: Fever ≥ 4–5 days + ≥ 4 of 5 principal clinical criteria:

1. Bilateral nonexudative bulbar conjunctival injection
2. Oral mucosal erythema, cracked red lips, or strawberry tongue
3. Polymorphous rash (maculopapular, diffuse erythroderma, erythema multiforme)
4. Extremity erythema/edema in acute phase or periungual peeling in subacute
5. Cervical lymphadenopathy (≥ 1.5 cm diameter, usually unilateral)

Incomplete KD: Fever ≥ 5 days + 2–3 compatible features (or infant <6 mo with fever ≥7 days) + CRP ≥ 3.0 mg/dL or ESR ≥ 40 mm/hr PLUS either ≥ 3 supplemental lab criteria (anemia, platelets ≥450k after d7, albumin ≤3.0 g/dL, elevated ALT, WBC ≥15k, urine WBC ≥10/hpf) OR Positive Echocardiogram (LAD/RCA Z ≥ 2.5, CAA, or ≥3 features: decreased LV function, MR, pericardial effusion, Z 2.0–2.5).

2. Follow-up & Surveillance Schedule AHA 2024 Table 2

Long-term surveillance tailored to the patient's maximum and current coronary artery involvement.

Tailored Surveillance Protocol

Please enter coronary measurements above to generate the patient's personalized follow-up schedule.

Risk Level	Description	Clinic & Echo Follow-up	Ischemia Stress Tests	Advanced Imaging (CTA/CMR)	Physical Activity
Level 1	No CA involvement (Z < 2)	1–2 wk (consider 4–6 wk if suboptimal or abnormal labs); discharge 4 wk to 1 yr	None	None	Full activity, promotion at every visit
Level 2	Dilation only (Z 2 to <2.5)	1–2 wk (visit at 6 wk if abnormal); 1 yr; discharge if normal. Assess q2–5y if persistent.	None	None	Full activity, promotion at every visit
Level 3.1	Small CAA, persistent (Z 2.5 to <5)	1 wk (weekly if enlarging until stable); 6 wk; 6 mo; 12 mo; then yearly	Every 3–5 years	Consider CTA at 1 yr baseline; q3–5y	Promotion counseling; restrict contact
Level 3.2	Small CAA, regressed to normal/dilation	1 wk; 6 wk; 1 yr; 5 yr (discharge if stress test & CTA normal)	Every 5 years	Consider CTA at 1 yr; if inducible ischemia	Full activity promotion
Level 4.1	Medium CAA, persistent (Z 5 to <10, <8mm)	1 wk (weekly until stable); 6 wk; 3 mo; 6 mo; 12 mo; then yearly	Every 2–5 years	Consider CTA at 1 yr baseline; q2–5y	Promotion; consider restrict contact; self-limit
Level 4.2	Medium CAA, regressed to small	1 wk; 6 wk; 6 mo; 12 mo; then yearly	Every 3–5 years	Consider CTA at 1 yr baseline; q3–5y	Promotion; restrict contact; self-limit
Level 4.3	Medium CAA, regressed to normal/dilation	1 wk; 6 wk; 6 mo; 12 mo; every 2 years	Every 4–5 years	Consider CTA at 1 yr; if inducible ischemia	Promotion; restrict contact; self-limit
Level 5.1	Large/Giant CAA, persistent (Z ≥ 10 or ≥ 8mm)	1 wk (weekly until stable); 6 wk; 3, 6, 9, 12 mo; then every 6–12 mo	Every 6–12 months	Baseline CTA within 2–6 mo; q1–5y or invasive angiography	Promotion; restrict contact; self-limit
Level 5.2	Large/Giant CAA, regressed to medium	1 wk (weekly until stable); 6 wk; 3, 6, 9, 12 mo; then every 6–12 mo	Every 2–5 years	Consider CTA at 1 yr baseline; q2–5y	Promotion; restrict contact; self-limit
Level 5.3	Large/Giant CAA, regressed to small	1 wk; 6 wk; 3, 6, 9, 12 mo; then yearly	Every 3–5 years	Consider CTA at 1 yr baseline; q3–5y	Promotion; restrict contact; self-limit
Level 5.4	Large/Giant CAA, regressed to normal/dilation	1 wk; 6 wk; 3, 6, 9, 12 mo; then every 1–2 years	Every 3–5 years	Consider CTA at 1 yr baseline; q3–5y	Promotion; restrict contact; self-limit

3. Antiplatelet, Anticoagulant & Medical Therapy AHA 2024 Update · DOACs & Acute Protocols

Evidence-based thromboprophylaxis ladders, DOAC updates, acute intensification, IVIG resistance rescue, and emergency MI management.

Tailored Thromboprophylaxis Regimen

Please enter coronary measurements above to view recommended medical therapy.

Medication	Mechanism / Class	Pediatric Dosing	Target Range / Monitoring	Key Clinical Points
Aspirin (ASA)	Antiplatelet (COX-1 inhibitor)	Acute phase: 30–50 mg/kg/day divided q6h until afebrile 48–72h. Maintenance / Antiplatelet: 3–5 mg/kg once daily (max 81–325 mg/day).	Clinical response. Platelet aggregation if resistance suspected.	Avoid NSAIDs (ibuprofen blocks antiplatelet effect). Defer live vaccines (MMR, Varicella) for 11 mo after IVIG. Inactivated flu vaccine recommended.
Clopidogrel	P2Y₁₂ ADP-receptor inhibitor	0.2–1.0 mg/kg once daily PO (typical infant/child dose ~0.2 mg/kg/day; adult max 75 mg/day)	Clinical observation; monitor for bruising/bleeding.	Used in DAPT for Medium CAA (Level 4.1), ASA allergy/resistance, or in Triple Therapy for Giant CAA / thrombosis.
Warfarin	Vitamin K antagonist (factors II, VII, IX, X)	Load with 0.2 mg/kg/day, maintain with ~0.1 mg/kg/day titrated to INR.	Target INR: 2.0 – 3.0 (Daily until stable, then at least monthly).	Indicated for Giant CAA (Level 5.1). Avoid in 1st trimester of pregnancy (teratogenic). Many food/drug interactions.
LMWH (Enoxaparin)	Factor Xa inhibitor	<2 months: 1.5 mg/kg SC q12h >2 months: 1.0 mg/kg SC q12h	Target anti-Factor Xa: 0.5 – 1.0 U/mL (drawn 4–6 h post-dose).	Preferred in infants & acute evolving aneurysms. Monitor antithrombin III if target anti-Xa not reached.
DOACs (Direct Oral Anticoagulants) AHA 2024 Update	Direct Factor Xa / Thrombin inhibitors (Apixaban, Edoxaban)	Apixaban: Weight-based twice daily (SAXOPHONE trial) Edoxaban: Weight-based once daily (ENNOBLE-ATE trial)	Infrequent monitoring; no routine INR testing required.	2024 AHA Update notes DOACs provide a convenient and safe alternative to Warfarin/LMWH with fewer dietary/drug interactions. Reversal agents available.
Statins (Atorvastatin)	HMG-CoA reductase inhibitor	0.125 to 0.75 mg/kg/day PO (evaluated in children ≥2 yrs with CAA)	Lipid profile, liver enzymes (ALT/AST), CPK.	Pleiotropic anti-inflammatory & endothelial stabilization benefits for persistent/regressed CAA (Level 3–5). Avoid concurrent cyclosporine (CYP3A4).
β-Blockers	Cardioselective β-blockade	Carvedilol, Metoprolol succinate, or Bisoprolol	Heart rate & blood pressure.	May be considered in large/giant aneurysms (Level 5) to reduce myocardial oxygen demand and wall stress.

Acute Initial & Primary Intensification (AHA 2024)

Standard Initial: IVIG 2 g/kg as single infusion over 8–12h + Aspirin 30–50 mg/kg/day.
High-Risk Primary Intensification (Dual Therapy): Indicated if Age <6 mo, Baseline Z ≥ 2.5, or Son Score ≥ 3:
- Infliximab: 10 mg/kg IV single infusion over 2h with IVIG; OR
- Prednisolone (RAISE protocol): 2 mg/kg/day IV divided q8h for 5d, then PO prednisolone 2 mg/kg/day with slow taper over 15d once CRP normalizes (+ famotidine for GI prophylaxis).

IVIG Resistance & Refractory KD Protocols

Definition: Persistent or recrudescent fever ≥ 36h after completion of first IVIG infusion.
First-Line Rescue Options:
- Infliximab: 10 mg/kg IV over 2h (KIDCARE trial: faster defervescence, shorter stay).
- Second IVIG Infusion: 2 g/kg IV over 8–12h.
- Pulse Methylprednisolone: 20–30 mg/kg/day IV for 3 consecutive days.
Refractory Multi-Agent Options:
- Anakinra (IL-1RA): 2–10 mg/kg/day IV/SC divided q12h.
- Cyclosporine: 5 mg/kg/day PO divided q12h (target 2h level 300–600 ng/mL; + Mg supplement).

🚨 Acute Myocardial Infarction / Coronary Thrombosis Management (AHA 2024 Figure 3)

Peak MI risk occurs in the first 2–3 months in large/giant CAA. Presenting symptoms in infants include irritability, unexplained crying, pallor, and diaphoresis; in older children chest/abdominal pain and vomiting.

STEMI Pathway:

Time to cath lab <90 min: Urgent transfer for Primary PCI / catheter thrombectomy.
Cath lab >90 min or small infant (no catheters): Fibrinolysis (tPA) or emergent CABG.

Pediatric tPA Fibrinolysis Protocol:

Alteplase (tPA): 0.05 to 0.1 mg/kg/h IV for 6–12 h (max 2 mg/h).
Check Fibrinogen (>150 mg/dL; give FFP 10–20 mL/kg if low).
Unfractionated Heparin: 75 U/kg bolus then 20 U/kg/h (target ACT 200–250s).

Evidence Base & Key References

Jone P-N, Tremoulet A, Choueiter N, et al. Update on Diagnosis and Management of Kawasaki Disease: A Scientific Statement From the American Heart Association. Circulation. 2024;150:e481–e500. Correction: Circulation. 2025;151:e863.
McCrindle BW, Rowley AH, Newburger JW, et al. Diagnosis, Treatment, and Long-Term Management of Kawasaki Disease: A Scientific Statement for Health Professionals From the American Heart Association. Circulation. 2017;135:e927–e999.
McCrindle BW, Li JS, Minich LL, et al. Coronary artery involvement in children with Kawasaki disease: risk factors from analysis of serial normalized measurements. Circulation. 2007;116:174–179.
Dallaire F, Dahdah N. New equations and a critical appraisal of coronary artery Z scores in healthy children. J Am Soc Echocardiogr. 2011;24:60–74.
Son MBF, Gauvreau K, Tremoulet AH, et al. Risk model development and validation for prediction of coronary artery aneurysms in Kawasaki disease in a North American population. J Am Heart Assoc. 2019;8:e011319.
Kobayashi T, Inoue Y, Takeuchi K, et al. Prediction of intravenous immunoglobulin unresponsiveness in patients with Kawasaki disease. Circulation. 2006;113:2606–2612.
Kobayashi T, Saji T, Otani T, et al. (RAISE study). Efficacy of immunoglobulin plus prednisolone for prevention of coronary artery abnormalities in severe Kawasaki disease. Lancet. 2012;379:1613–1620.

fetal-echo.org · Clinical Calculator Suite · Dr Mridul Agarwal, Pediatric Cardiologist

Kawasaki Disease Coronary & Risk Assessment Report

fetal-echo.org · Guidelines: AHA 2024 Update & 2017 Statements

Patient ID / Name: —	Age: —	Sex: —
Weight: — kg	Height: — cm	BSA (Haycock): — m²

Coronary Artery Measurements & Z-Scores (Boston · McCrindle 2007)

Artery	Dimension (mm)	Z-Score	AHA Classification
LMCA (Left Main)	—	—	—
LAD (Left Anterior Descending)	—	—	—
LCx (Left Circumflex)	—	—	—
RCA (Right Coronary)	—	—	—

Maximum Coronary Z-Score: — | AHA Risk Classification: —

Risk Stratification & Diagnostic Models

Son et al. 2019 Score (CAA Risk): —

Kobayashi Score (IVIG Resistance): —

Recommended Management & Follow-up Schedule (AHA 2024 Table 2)

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Report generated via fetal-echo.org Clinician Signature: ___________________________