Novel Echocardiographic Indices for Assessing the Left Main Coronary Artery in Children With Kawasaki Disease

BACKGROUND Kawasaki disease (KD) is the most common cause of acquired myocardial infarction in children. Coronary artery involvement is the most serious feature of this vasculitis syndrome. Timely diagnosis of coronary artery involvement is of utmost importance since it can prevent long-term morbidity and mortality. The current methods for the diagnosis of coronary artery dilation in KD are inconsistent and are also not capable of detecting all the abnormal coronary arteries or the so-called occult dilations present. OBJECTIVES The aim of this study was to determine the sensitivity and specificity of three novel allometric indices for the diagnosis of left main coronary artery (LMCA) involvement in KD. METHODS We performed a prospective case-control study in 69 children (38 with KD and 31 healthy children). All the followed up patients underwent two complete echocardiographic examinations at the time of admission and 4 - 6 weeks later. We measured the size of the LMCA, coronary sinus (CS) and aorta (A) and calculated the LMCA/CS, LMCA/A and LMCA/CS/A ratios. We also calculated the cut-off scores for each index using receiver operating characteristic curves both in the acute phase and 4 - 6 weeks later. RESULTS In the acute phase, the cut-off scores for the LMCA/A ratio was > 0.23; LMCA/CS, > 0.44; and LMCA/CS/A, > 0.03. This implied 60% sensitivity and 80% specificity for the detection of abnormal LMCA in KD. Four to six weeks after the acute phase, the LMCA/A cut-off score was > 0.23; LMCA/CS, > 0.73; and LMCA/CS/A, > 0.73. This implied 100% sensitivity and 100% specificity for the detection of abnormal LMCA. There was a significant decrease in the size of the CS in comparison with the control group (1.92 ± 0.363 mm; P = 0.007 and 0.023). CONCLUSIONS The LMCA/A, LMCA/CS and LMCA/CS/A ratios seem to provide simple and patient-specific indices for the detection of abnormal LMCA in KD, both in the acute and subacute phase. Further, a decrease in the size of the CS may imply a decrease in coronary artery flow in the acute and subacute phases of KD.