INFLUENCE OF INTRACORONARY DIPYRIDAMOLE ON THE INCIDENCE OF RESTENOSIS FOLLOWING PTCA - A PROSPECTIVELY RANDOMIZED INVESTIGATION

Background: Restenosis after PTCA remains a serious long-term complica tion of balloon angioplasty occurring in 30 to 50% of patients. Platel ets play a crucial role in the pathogenesis of restenosis following PT C. Dipyridamole has been shown to inhibit platelet aggregation in huma ns. Its action as an antithrombotic drug can bs attributed to differen t mechanisms including inhibition of platelet phosphodiesterase and in hibition of the cellular uptake of adenosine. Patients and Methods: Th e purpose of the following study was to investigate the effect of an i ntracoronary infusion of dipyridamole on the incidence of angiographic and clinical restenosis. In 763 balloon angioplasties patients were r andomly allocated to receive either convention,ll pretreatment (hepari n 15000 IE, aspirin 500 mg i. v.) or an additional intracoronary infus ion of dipyridamole (0,5 mg/kg body weight). Conventional pretreatment was performed in 388 interventions (61 interventions in women, age 60 .5 +/- 8.7 years; 47 interventions for acute Coronary syndromes); in 3 75 interventions additional intracoro- 5 nary dipyridamole was infused (58 interventions in women, age = 59.6 +/- 9.6 years; 57 intervention s for acute coronary syndromes). Results: As compared io conventional pretreatment intracoronary dipyridamole application was associated wit h a reduction in angiographic restenosis from 43.0% to 36.8% and a red uction of target vessel revascularisation by 15.5% but failed to reach statistical significance. These results were due to an increase I in net gain following dipyridamole application. Conclusion: Intracoronary pretreatment with dipyridamole prior to PTCA fails to reduce the inci dence of angiographic restenosis and target vessel revascularisation s ignificantly. However, a moderate improvement of long-term followlow-u p can be achieved.