Background/Purpose: Kawasaki disease (KD) is a common childhood vasculitis associated with coronary artery aneurysms (CAA). Based on our recent work, the incidence of KD has significantly increased in Ontario over the past two decades. However, the risk of long-term cardiovascular events in children without large CAA remains unknown. Our objectives were to: 1) determine the risk and timing of long-term cardiovascular events (diagnoses and procedures) among KD survivors; and 2) determine the risk of all-cause mortality.

Methods: We identified all children (0-18yr) surviving hospitalization with a KD diagnosis in Ontario between 1995-2018, through validated algorithms using population health administrative databases. We included only the first eligible hospitalization and excluded children previously diagnosed with KD and non-residents. KD cases were matched to 100 non-exposed controls by age, sex and index year. Follow-up continued until death or March 2019 (maximum 24 years). We determined incidence rates (per 1000 person-years (py)) and unadjusted hazard ratios (HR) for cardiovascular events, major adverse cardiac events (MACE; cardiovascular death, myocardial infarction (MI) or stroke composite) and all-cause mortality, comparing KD and non-exposed cohorts during the following time periods: 0-1yr, 1-5yr, 5-10yr and >10yr.

Results: Among 4,597 KD survivors, 746 (16.2%) experienced cardiovascular events, 79 (1.7%) MACE and 9 (0.2%) died during median 11.1-year follow-up (Table 1). The most frequent cardiovascular events among KD survivors were ischemic heart disease (231 children, 4.6 events/1000py), arrhythmias (229, 4.5/1000py), hypertension (159, 3.1/1000py) and peripheral vascular disease (107, 2.1/1000py). KD survivors were at increased risk of cardiovascular events and MACE vs. non-exposed children between 0-1yr, 1-5yr and 5-10yr, and cardiovascular events at >10yr follow-up (Table 1). KD survivors experienced cardiovascular events sooner than non-exposed children (Figure 1; Kaplan-Meier curve, log-rank p< 0.0001). Their risk of cardiovascular events was highest in the first year post-discharge (HR 14.13 [12.57-15.89]). KD survivors were at increased risk of undergoing percutaneous coronary intervention or coronary artery bypass grafting throughout follow-up (KD: 12 (0.3%) vs. non-exposed: 63 (0.01%), HR 14.68 [7.73-27.88]). KD survivors were at lower risk of mortality throughout follow-up (KD: 9 (0.2%) vs. non-exposed: 2,012 (0.4%), HR 0.42 [0.22-0.81]).

Conclusion: Children diagnosed with KD remain at increased risk of cardiovascular events for >10 years after index hospitalization. Despite the prevalence of cardiovascular disease, they have a lower risk of long-term mortality. Our findings highlight the need for cardiovascular disease surveillance and risk reduction strategies among KD survivors.

Figure 1. Composite cardiovascular event-free survival among KD survivors vs. non-exposed children

Figure 2. Patient survival among KD survivors vs. non-exposed children

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/late-cardiovascular-outcomes-in-children-with-kawasaki-disease-a-population-based-cohort-study/