Evaluation of left ventricular function in immunoglobulin‐resistant children with Kawasaki disease: a two‐dimensional speckle tracking echocardiography study

BACKGROUND: Kawasaki disease (KD) patients who are unresponsive to intravenous immune globulin (IVIG) have a high occurrence of coronary artery lesions (CALs). The characteristics of left ventricular (LV) function alternation in IVIG‐resistant patients are not well‐described. HYPOTHESIS: Two‐dimensional speckle tracking echocardiography (STE) is a useful technique that can accurately detect myocardium subclinical dysfunction in resistant patients and may assist in differentiating patients with KD at a higher risk of IVIG resistance. METHODS: A consecutive sample of 50 IVIG‐resistant patients (25 males, 2.2 ± 0.9 years), 50 IVIG‐responsive patients (27 males, 2.2 ± 0.7 years) and 50 normal subjects (27 males, 2.1 ± 0.9 years) were analyzed using STE, and receiver operating characteristic curve (ROC) analysis was utilized to determine the threshold values of STE parameters associated with IVIG resistance. RESULTS: Compared with normal children, IVIG‐resistant patients had lower global longitudinal strain (GLS) (15.82 ± 3.32 vs 20.01 ± 2.98, P = 0.000) and lower global circumferential strain (GCS) (16.65 ± 3.12 vs 20.11 ± 2.86, P = 0.042). Both GLS and GCS in IVIG‐resistant patients were significantly lower than in IVIG‐responsive patients (15.82 ± 3.32 vs 19.95 ± 3.01, 16.65 ± 3.12 vs 19.01 ± 3.00, P = .000, .030, respectively). ROC analysis demonstrated that the absolute values of GLS < 16.8% and GCS < 15.9% were optimal predictors of IVIG unresponsiveness (area under the curve = 0.78, 0.75; sensitivity = 0.83, 0.79; specificity = 0.69, 0.65, respectively). CONCLUSION: IVIG‐resistant patients presented with more severe LV systolic dysfunction compared with IVIG‐responsive patients, which may be the result of myocarditis rather than CALs. STE may be a helpful diagnostic tool that provides supportive criteria to detect KD patients at a higher risk of IVIG resistance.