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.