Influence of intracoronary dipyridamole on the incidence of restenosis following PTCA - A prospectively randomised investigation

Background: Restenosis after PTCA remains a serious long-term complication of balloon angioplasty occurring in 30 to 50% of patients. Platelets play a crucial role in the pathogenesis of restenosis following PTC. Dipyridamole has been shown to inhibit platelet aggregation in humans. Its action as an antithrombotic drug can bs attributed to different mechanisms including inhibition of platelet phosphodiesterase and inhibition of the cellular uptake of adenosine. Patients and Methods: The purpose of the following study was to investigate the effect of an intracoronary infusion of dipyridamole on the incidence of angiographic and clinical restenosis. In 763 balloon angioplasties patients were randomly allocated to receive either convention,ll pretreatment (heparin 15000 IE, aspirin 500 mg i. v.) or an additional intracoronary infusion 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 375 interventions additional intracoro- 5 nary dipyridamole was infused (58 interventions in women, age = 59.6 +/- 9.6 years; 57 interventions for acute coronary syndromes). Results: As compared io conventional pretreatment intracoronary dipyridamole application was associated with a reduction in angiographic restenosis from 43.0% to 36.8% and a reduction 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 incidence of angiographic restenosis and target vessel revascularisation significantly. However, a moderate improvement of long-term followlow-up can be achieved.