Myocardial Contractile Reserve Impairment in Patients with Kawasaki Disease During Convalescent Phase: A Study Based on Two-Dimensional Speckle-Tracking Stress Echocardiography.

Persistent myocardial impairment proved by histopathologic studies universally existed in patients with Kawasaki disease (KD); however, the long-term effects on myocardial contractile reserve in KD patients, especially on patients without coronary artery lesions (CALs), is still unknown. The aim of this study was to investigate myocardial contractile reserve in KD patients during late convalescent stage by speckle-tracking adenosine triphosphate (AT) echocardiography. A total of 63 antecedent KD patients at least 4 years after the disease onset and 40 age- and gender-matched normal controls were prospectively enrolled. Based on coronary artery status, patients were further divided into CALs group and non-CALs (NCALs) group. Left ventricular ejection fraction (LVEF), speckle-tracking derived-global longitudinal strain (GLS), and global circumferential strain (GCS) were evaluated at rest and during AT peak stress. Myocardial contractile reserve parameters including ΔLVEF, ΔGLS, and ΔGCS were defined as the absolute value differences in LVEF, GLS, and GCS from rest to peak stress. Of the patients with KD, 44 had normal coronary artery and 19 had CALs. KD patients regardless of CALs had lower GLS and GCS than normal controls at resting condition. Significant decreases in ΔGLS and ΔGCS were observed in patients with CALs compared to normal controls under peak stress. While ΔGLS and ΔGCS increased in patients without CALs following stress, improvements were significantly weaker than those in normal controls. However, no significant differences in LVEF at rest and ΔLVEF under peak stress between KD patients irrespective of CALs and normal controls were found. In addition, when comparing with patients with NCALs, patients with CALs had lower GLS and GCS at rest and lower ΔGLS and ΔGCS in response to stress. Subclinical abnormality of myocardial contractile reserve existed in KD patients during late convalescent phase. Even patients without CALs need an additional surveillance on myocardial contractile reserve in the long-term follow-up. These novel findings by speckle-tracking stress echocardiographic analysis may provide more valuable clinical implications for better understanding and long-term management of such patients.