[Effects of isosorbide dinitrate on coronary and systemic circulation in children: comparison with dipyridamole]

The effects of isosorbide dinitrate (ISDN) on the coronary and systemic circulation were evaluated in comparison with the effects of dipyridamole (DP) in 8 children with histories of Kawasaki disease and angiographically normal coronary arteries. ISDN (100 micrograms/kg) was administered as an intracoronary injection. DP was administered intravenously at the rate of 0.56 mg/kg for 4 min. In the coronary circulation, DP induced a significant reduction of the afterload, resulting in an increase in cardiac output. However, the pulmonary artery pressure, pulmonary capillary wedge pressure and left ventricular end-diastolic pressure, which are related to the preload, were significantly reduced one min after the ISDN injection. The systolic blood pressure was reduced, while the heart rate was increased. The cardiac output, pressure-rate product or systemic vascular resistance showed no significant change. The systolic work index, however, was significantly reduced. In the coronary circulation, DP significantly increased the coronary sinus blood flow due to dilatation of the resistant vessels. However, ISDN significantly dilated the conductant vessels by 4.0 to 12.9% in diameter. There was, however, no change in the coronary blood flow, coronary perfusion pressure nor coronary vascular resistance. The grade of dilatation of the coronary vessels caused by ISDN was lower in children than in adults.