EFFECTS OF INTRACORONARY ADENOSINE-TRIPHOSPHATE ON CORONARY FLOW VELOCITY DYNAMICS IN CHILDREN

To assess the usefulness of adenosine triphosphate (ATP) as an alterna tive agent for functional determination of coronary circulation in chi ldren and to reveal the dose-response kinetics of intracoronary ATP, s ystemic hemodynamics and spectral coronary flow velocity dynamics usin g Doppler guide wire were measured during hyperemic responses to an in tracoronary bolus injection of ATP (0.01 mu g/kg, 0.1 mu g/kg and 1.0 mu g/kg) in consecutive 40 Kawasaki disease patients (age: 8.4 +/- 5.1 years, 30 boys and 10 girls) without angiographic coronary lesions. A TP did not produce any significant change in heart rate, systolic bloo d pressure and mean blood pressure, but mildly decreased diastolic blo od pressure. The coronary flow reserve (CFR) calculated as a ratio of hyperemic to basal averaged peak velocity (APV) for ATP was 2.05 +/- 0 .31, 2.26 +/- 0.38 and 2.50 +/- 0.51 in LAD, and 2.24 +/- 0.28, 2.44 /- 0.41 and 2.60 +/- 0.47 in RCA, respectively, for each of the three doses. There was no statistical significance between the mean values o f CFR in LAD with ATP (1.0 mu g/kg: 2.39 +/- 0.16) and papaverine (0.1 5 mu g/kg: 2.43 +/- 0.16) in six patients without angiographic coronar y lesions. The maximal coronary hyperemia was reached rapidly after in tracoronary bolus injection of ATP in all doses (10, 10-15 and 15-20 s econds in both LAD and RCA, respectively, for each of the three doses) . The time required for APV to return to basal levels (< T10%) increas ed with the dose of ATP (30, 55 and 110 seconds in LAD and 35, 45 and 100 seconds in RCA, respectively, for each of the three doses). Three patients (3/40: 7.5%) developed transient (< 5 seconds) asymptomatic s econd degree atrioventricular block, but no patient had clinically sig nificant arrhythmias. The change ratio in QTc interval after ATP injec tion was 1.96 +/- 1.87% (not significant). In addition, an intracorona ry injection of ATP did not increase the absolute angiographic coronar y luminal diameter. This study indicates that ATP is a safe alternativ e agent for pharmacological induction of coronary hyperemia for evalua tion of coronary stenotic lesions and for the study of coronary circul ation and coronary flow reserve in children.