Assessment of Coronary Artery Flow after Infusion of Adenosine in Kawasaki Disease by Transthoracic Echocardiography

PURPOSE: Coronary arterial lesions after Kawasaki disease may cause coronary endothelial dysfunction without initial coronary dilatation, stenosis, and aneurysm. TTE (transthoracic echocardiography) is a non-invasive and widely used method in clinical practice. Adenosine is short acting drug and induces coronary vasodilatation. This study was designed to measure accurate coronary dysfunction by adenosine infusion. Coronary flow reserve(CFR) is defined as "the ratio of peak hyperemic to basal coronary flow velocity(CFV) in the proximal coronary vessel". CFR measurements has provided useful clinical and physiologic information in pediatric patients with congenital or acquired heart disease. METHODS: We examined 29 patients who had a history of Kawasaki disease. 19 patients discontinued low dose aspirin(5 mg/kg/d) after recovered from coronary dilatation and 10 patients have taken low dose aspirin because they had coronary dilatation. Adenosine was infused at 160 microgram/kg/min for 4 min. Diameter, velocity and integral of coronary artery were measured. RESULTS: Diameter and velocity were increased after adenosine infusion in both coronary arteries. A reduced CFR of both coronary arteries was noted in unrecovered group. CONCLUSION: CFR measured by TTE can predict the presence of significant coronary dysfunction in convalescent phase of Kawasaki disease.

Correlations between Coronary Flow Reserve and the Presence of Viable Myocardium after Acute Anterior Myocardial Infarction

BACKGROUND: Coronary flow reserve (CFR) was defined as the ability to increase coronary blood flow maximally in response to demand. The presence of viable myocardium in an infarcted zone indicates the presence of an intact microvasculature. We hypothesized that coronary flow reserve, which assesses the microcirculation, might be associated with the presence of viable myocardium. METHODS: Thirty seven patients with acute anterior myocardial infarction (mean age 55+/-10, 25 males) were enrolled and abnormal 127 segments were analyzed. Dobutamine stress echocard-iography (5 to 20 g/kg/min) was performed before coronary angiography (6+/-3 days after acute myocardial infarction (AMI)). Coronary flow reserve in infarct-related artery was measured at distal site to lesion immediately after successful angioplasty (7+/-2 days after AMI, with residual stenosis less than 20%) by using intracoronary Doppler flow wire. And follow-up 2-dimentional transthoracic echocardiography was performed in 26 patients during 333+/-161 (range of 109-780) days after acute myocardial infarction. Improvement of wall motion at least one segment by one more grade in dobutamine stress echocardiography was defined as contractile reserve. Viable myocardium was defined as the improvement of wall motion in transthoracic echocardiography during follow-up periods. RESULTS: In 26 patients, viable myocardium was detected in 19 patients (73%) and their mean CFR was 1.74+/-0.42, which was significantly increased than 1.16+/-0.14 of CFR of patients without viable myocardium (p<0.001). The agreement of CFR score and presence of viable myocardium in AMI was excellent when CFR was above 1.3 (Area under the curve was 0.906 in receiver operating characteristic (ROC) curve). Sensitivity and specificity to detect viable myocardium in CFR more than 1.3 were 84% & 85% respectively. CONCLUSION: CFR was increased in patients with viable myocardium, and the cut-off value of CFR more than 1.3 was agreed excellently to detect viable myocardium.