CORONARY ARTERIAL FLOW-VELOCITY DYNAMICS IN CHILDREN WITH ANGIOGRAPHICALLY NORMAL CORONARY-ARTERIES

Background There have been few reports about coronary hemodynamics in children during the process of growth. In the present study, to assess the characteristics of coronary flow dynamics in children, we examine d the phasic coronary flow-velocity (CFV) patterns at rest and during peak hyperemic responses in children with angiographically normal coro nary arteries. Methods and Results Spectral Doppler phasic coronary fl ow velocity was recorded with a 0.018-in intracoronary Doppler guidewi re at rest and during peak responses after intracoronary bolus injecti on of ATP in 30 patients with Kawasaki's disease (age, 8.2+/-5.1 years ; 24 boys and 6 girls) without angiographic coronary lesions. Average peak velocity (APV), maximum peak velocity (MPV), and diastolic-to-sys tolic velocity ratio (DSVR) were evaluated in the left anterior descen ding coronary artery (LAD), left circumflex artery (LCx), and right co ronary artery (RCA). Coronary vasodilator reserve (coronary flow reser ve [CFR]) was calculated as the ratio of ATP-induced hyperemic to base line APV. Flow-velocity parameters in RCA were significantly lower tha n those in the LAD and LCx in both proximal and distal portions. Altho ugh the distal LCx had significantly lower values of APV and MPV than did the proximal LCx, there was no significant difference between the and MPV. All three coronary vessels showed a diastolic dominant flow p attern in each segment. This coronary flow pattern was less marked in the RCA than in the LCA. All three coronary vessels showed a significa nt increase in APV and a significant decrease in DSVR after ATP admini stration. CFR was significantly lower in the LCx than in the LAD or RC A (P<.01: 1.93+/-0.34 in LCx versus 2.32+/-0.42 in LAD and 2.37+/-0.44 in RCA). From the view of aging, it was revealed that APV values in t hree vessels were higher in the younger group than in the older group. CFR values in the LAD and LCx were significantly lower in the younger group than in the older group (P<.001 in LAD: 2.0+/-0.28 in the young er versus 2.53+/-0.37 in the older; P<.01 in LCx: 1.61+/-0.15 in the y ounger versus 2.06+/-0.31 in the older). In addition, intracoronary in jection of ATP did not increase the absolute angiographic coronary lum inal diameter. Conclusions With the use of an intracoronary Doppler gu idewire, we demonstrated that there are some characteristic findings i n CFV dynamics in childhood. These physiological characteristics in CF V dynamics that occur with aging and occur in each vessel must be take n into consideration in the study of the coronary circulation in child ren.