Effect of dipyridamole on the blood flow in coronary aneurysms resulting from Kawasaki disease.

Dipyridamole has been widely used in Japan to treat patients with a coronary aneurysm resulting from Kawasaki disease, but its effect in these patients has not been established. In the present study we assessed the effect of dipyridamole on the coronary arteries of patients with a history of Kawasaki disease by measuring the diameter of the coronary arteries and by quantifying the disappearance time of contrast medium (runoff time) on coronary angiography. Intravenous injection of dipyridamole increased the diameter of nondilated arteries by 7.9%. Its effect on the diameter of dilated coronary arteries (coronary aneurysm) was less than 3% (p < 0.01). Runoff time of dilated coronary arteries was significantly (p < 0.01) greater than that of nondilated coronary arteries. Dipyridamole accelerated runoff time not only in nondilated coronary arteries (p < 0.01) but also in coronary arteries with various degrees of dilatation (p < 0.01). We conclude that dipyridamole increases blood flow in coronary arteries without dilating the proximal aneurysm in children with a history of Kawasaki disease.