125 - FACTORS ASSOCIATED WITH LARGE VERSUS GIANT CORONARY ARTERY ANEURYSMS AFTER KAWASAKI DISEASE

Background: Large and giant are terms often used interchangeably to describe CA aneurysms with Z-scores of 10+. Within this category, higher Z-scores have been reported to be associated with a greater risk of both thrombosis and stenosis, although differences related to the acute KD episode have not been described.

Methods: Patients assessed with acute KD at The Hospital for Sick Children from 1995-2023 and a maximum CA Z-score of 10+ in any branch (large aneurysms) were included. Demographics, clinical features and treatment were compared.

Results: Of 2653 patients with sufficient echo data, 2416 had Z-scores < 2.5, 170 had Z-scores 2.5 to < 10 (small to medium aneurysms), and 67 patients had Z-scores of 10+. Of these 67 patients, 33 had Z-scores of 10 to < 30, which we defined as large aneurysms, and 34 had Z-scores of 30 or more, which we defined as giant aneurysms. Patients with giant vs. large aneurysms had a greater number of CA branches involved with Z-scores of 10+ (3 or more branches 56% of giant vs 12% of large group; p< 0.001, FIGURE). The left anterior descending was the branch most frequently involved for both groups, followed by the right CA. Groups did not differ by sex or ethnicity, although the giant group was significantly older (median 8.1 vs 4.8 years; p< 0.03, FIGURE). Both groups had a similar number of KD criteria, but the giant group had greater total days of fever (median 13.5 vs. 11; p< 0.03). Both groups had a high prevalence of having missed KD (giant 63%, large 53%; p=0.45). Groups did not differ regarding presentation with shock, ICU admission or initial hospital length of stay. Groups did not differ regarding any laboratory feature at either presentation or at the most extreme during admission. Patients with giant aneurysms were less likely to have received IVIG (78% vs. 88%; p< 0.04), but more likely to have received multiple doses (35% vs. 15%; p< 0.03). There were no differences regarding steroids. One patient in each group received a thrombolytic agent.

Conclusions: Patients with giant vs. large CA aneurysms were older and had a greater extent of CA involvement. There were few other differences, although missed diagnosis was highly prevalent with a lower likelihood of timely treatment. Prevention of giant aneurysms will require prompt diagnosis and treatment, together with effective strategies to prevent the progression of CA involvement present at diagnosis.