[Effect of long-term cilostazol administration on coronary flow velocity and coronary flow reserve]

Cilostazol, a novel potent inhibitor of phosphodiesterase, increases coronary flow. The effects of cilostazol on coronary flow velocity and coronary flow reserve were studied in 103 patients with coronary artery disease who underwent coronary angiography. Cilostazol 200 mg/day was administered for 3 months (31 patients) or 6 months (37 patients), and coronary flow reserve were measured before and after the cilostazol administration. Coronary flow reserve were measured twice at an interval of 6 months in the control group (35 patients). The Doppler guide wire was advanced into the coronary artery with no significant vessel stenosis. After obtaining continuous baseline coronary flow velocity, an intracoronary infusion of papaverine (10 mg) was performed to measure coronary flow reserve. There were no significant differences in coronary flow velocity just before intracoronary papaverine infusion between the initial and follow-up studies in any of the 3 groups. Coronary flow reserve increased significantly after cilostazol administration in the 3 months and 6 months groups compared with before administration (3 months group: 2.8 +/- 0.8 vs 2.4 +/- 0.9, p < 0.05; 6 months group: 2.8 +/- 1.0 vs 2.4 +/- 0.7, p < 0.01). However, there was no significant difference in coronary flow reserve in the control group between follow-up and initial studies (2.7 +/- 0.8 vs 2.5 +/- 0.8, NS). In conclusion, the long-term oral administration of cilostazol for 3 or 6 months improves coronary flow reserve.