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Coronary arterial flow-velocity dynamics in children with angiographically normal coronary arteries
K Hamaoka1, Z Onouchi, Y Ohmochi
1Division of Pediatrics, Children's Research Hospital, Kyoto Prefectural University of Medicine, Japan.
Insights
This study reveals distinct coronary flow-velocity (CFV) patterns in children, showing vessel-specific differences and changes with aging. These findings are crucial for understanding pediatric coronary circulation dynamics.
Area of Science:
- Pediatric Cardiology
- Cardiovascular Physiology
- Medical Imaging
Background:
- Limited data exists on coronary hemodynamics in growing children.
- Understanding normal coronary flow is essential for diagnosing pediatric cardiovascular conditions.
Purpose of the Study:
- To characterize coronary flow-velocity (CFV) patterns at rest and during hyperemia in children.
- To assess age-related changes in coronary hemodynamics.
Main Methods:
- Used a 0.018-in intracoronary Doppler guidewire in 30 children (mean age 8.2 years) with normal coronary arteries.
- Measured phasic CFV, average peak velocity (APV), maximum peak velocity (MPV), and diastolic-to-systolic velocity ratio (DSVR).
- Administered intracoronary ATP to induce hyperemia and calculated coronary flow reserve (CFR).
Main Results:
- Coronary flow parameters were lower in the right coronary artery (RCA) compared to the left anterior descending (LAD) and left circumflex (LCx) arteries.
- Flow patterns were predominantly diastolic and less pronounced in the RCA.
- Coronary flow reserve (CFR) was lower in the LCx, and both APV and CFR showed significant age-related variations, with higher APV and lower CFR in younger children.
Conclusions:
- Intracoronary Doppler guidewire assessment reveals characteristic pediatric CFV dynamics.
- Age and vessel-specific physiological variations in CFV are important considerations for pediatric coronary circulation studies.
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 examined the phasic coronary flow-velocity (CFV) patterns at rest and during peak hyperemic responses in children with angiographically normal coronary arteries.
Methods And Results:
Spectral Doppler phasic coronary flow velocity was recorded with a 0.018-in intracoronary Doppler guidewire at rest and during peak responses after intracoronary bolus injection 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-systolic velocity ratio (DSVR) were evaluated in the left anterior descending coronary artery (LAD), left circumflex artery (LCx), and right coronary artery (RCA). Coronary vasodilator reserve (coronary flow reserve [CFR]) was calculated as the ratio of ATP-induced hyperemic to baseline APV. Flow-velocity parameters in RCA were significantly lower than those in the LAD and LCx in both proximal and distal portions. Although the distal LCx had significantly lower values of APV and MPV than did the proximal LCx, there was no significant difference between the proximal and distal portions of the LAD and RCA for APV and MPV. All three coronary vessels showed a diastolic dominant flow pattern in each segment. This coronary flow pattern was less marked in the RCA than in the LCA. All three coronary vessels showed a significant increase in APV and a significantly decrease in DSVR after ATP administration. CFR was significantly lower in the LCx than in the LAD or RCA (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 three 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: 2.01 +/- 0.28 in the younger versus 2.53 +/- 0.37 in the older; P < .01 in LCx: 1.61 +/- 0.15 in the younger versus 2.06 +/- 0.31 in the older). In addition, intracoronary injection of ATP did not increase the absolute angiographic coronary luminal diameter.
Conclusions:
With the use of an intracoronary Doppler guidewire, we demonstrated that there are some characteristic findings in CFV dynamics in childhood. These physiological characteristics in CFV dynamics that occur with aging and occur in each vessel must be taken into consideration in the study of the coronary circulation in children.