Adjunctive intracoronary dipyridamole in the interventional treatment of small coronary arteries: A prospectively randomized trial

Background Patients undergoing intracoronary stent placement or balloon ang ioplasty for the treatment of small coronary arteries are at an increased r isk of an adverse outcome from a higher incidence of abrupt closure and res tenosis. Intracoronary thrombus formation plays a key role in the pathogene sis of abrupt vessel closure and of restenosis. Dipyridamole prevents plate let aggregation by a mechanism that differs from aspirin. The purpose of th is study was to investigate the effect of intracoronary dipyridamole on acu te complications and restenosis after percutaneous transluminal coronary an gioplasty. Methods In a prospectively randomized study including 491 dilatations of co ronary arteries with a diameter <2.75 mm, additional intracoronary applicat ion of dipyridamole was compared with conventional pretreatment consisting of heparin and aspirin. Study end points were defined as incidence of abrup t vessel closure, myocardial infarction, angiographic restenosis, and targe t vessel revascularization rate. Results Intracoronary dipyridamole was associated with a significant reduct ion of abrupt vessel closure (2.8% vs 8.6%; P = .005) and a nonsignificant reduction of myocardial infarction (1.6% vs 4.5%; P = .07) after percutaneo us transluminal coronary angioplasty. Net gain 6 months after angioplasty w as significantly higher in the dipyridamole group (0.60 +/- 0.35 mm vs 0.42 +/- 0.34 mm; P <.001). However, dipyridamole foiled to reduce the incidenc e of angiographic restenosis (41.6% vs 49.1%; P = .11) and target vessel re vascularization rare (20.6% vs 269%; P =.12). Conclusions Intracoronary dipyridamole reduces the incidence of adverse car diovascular events in the first 48 hours after balloon angioplasty of small coronary arteries, Reduction of restenosis rates failed to reach statistic al significance. However, a significant increase in net gain was observed. Thus intracoronary application of dipyridamole should be considered in the treatment of small coronary arteries when intracoronary stenting is not app ropriate.