[Analysis of 41 cases of myocardial infarction in children with coronary artery lesion after Kawasaki disease]

Objective: To analyze the clinical characteristics,diagnosis and treatment of pediatric myocardial infarction (MI) patients with coronary artery lesions (CAL) after Kawasaki disease (KD). Methods: Clinical data including baseline characteristics, KD and CAL information, clinical symptoms at MI onset, electrocardiogram (ECG) and imaging findings, MI treatment, and clinical outcomes of 41 MI patients with CAL after KD admitted to the Children's Hospital of Fudan University from January 2017 to August 2024 were analyzed retrospectively. Results: (1) Demographic characteristics: a total of 41 patients were included (36 males and 5 females). The age at MI was 4.6 (2.3, 5.7) years, and time from KD onset to MI was 397 (50, 1 095) d. (2) Treatment of acute KD: only 15 patients (37%) received standard initial treatment within 10 days of KD onset with intravenous immunoglobulin 2 g/kg. The other 26 cases (63%) received non-standard treatment or no treatment. (3) Treatment of CAL before MI: the time from KD onset to CAL was 14 (10, 116) d, with CAL not identified before MI onset in 15 patients. Among the 26 cases diagnosed with CAL prior to MI, 9 cases received only single or dual antiplatelet drug, of which 7 cases received oral dipyridamole. The remaining 16 cases received antiplatelet drug combined with warfarin, but only 1 case achieved the target international standardized ratio of 1.5-2.5. Out of all 41 cases, only 1 case (2%) received standard antithrombotic treatment before MI onset. (4) Clinical symptoms of MI: at MI onset, 32 patients presented with different clinical symptoms, with typical MI symptoms such as chest tightness, chest pain, precordial discomfort in 18 cases, and cardiopulmonary arrest accompanied by syncope or convulsions in 10 cases. Other non-specific symptoms included abdominal pain, nausea, vomiting and pallor. Nine patients were asymptomatic and were found to have silent MI on follow-up. (5) ECG and imaging findings: ECG showed ST-T changes in 33 cases, and abnormal Q waves, and arrhythmias in the remaining patients; echocardiography indicated coronary artery aneurysm with thrombosis in 27 cases, reduced left ventricular ejection fraction in 18 cases, abnormal wall motion in 15 cases, and ventricular aneurysm in 3 cases. Thirty-seven patients underwent coronary angiography and (or) multi-slice spiral CT angiography, with 39 occluded vessels and 3 severe stenosis (≥75%), all of which were caused by giant aneurism with thrombus formation. (6) Treatment of MI: of the 32 patients with acute MI, 9 patients received successful cardiopulmonary resuscitation, 7 patients received intravenous thrombolysis, and 1 patient underwent percutaneous coronary balloon angioplasty. All of these patients received dual antiplatelet drugs and low-molecular-weight heparin at therapeutic doses following MI treatment. Sixteen patients received coronary artery bypass graft (CABG) treatment, all of which were successful. (7) Outcomes: the follow-up time was 994 (215, 1 832) d. Thirty-one patients showed improvement, 5 patients experienced disease progression or no change, 1 patient died, and 4 patients were lost to follow-up. Conclusions: MI in children with CAL after KD often occurs within 1 year after the onset of KD. MI can present with atypical clinical symptoms in children. CABG is the main treatment option in children severe CAL after KD who developed MI.