A randomized trial of low osmolar ionic versus nonionic contrast media in patients with myocardial infarction or unstable angina undergoing percutaneous transluminal coronary angioplasty

Objectives. The purpose of this study was to determine prospectively whether the differences in anticoagulant and antiplatelet effects of ionic and nonionic contrast media alter angiographic or clinical outcomes in patients with unstable ischemic syndromes undergoing percutaneous transluminal coronary angioplasty. Background. The interaction of platelets and thrombin with the endothelium of injured vessels contributes to thrombosis and restenosis after coronary angioplasty. Case reports and retrospective observations have reported an increased risk of thrombosis with the use of nonionic contrast media. Methods. A total of 211 patients with acute myocardial infarction or unstable angina undergoing coronary angioplasty were randomized to receive nonionic or ionic low osmolar contrast media. Coronary angiograms were assessed by a technician blinded to the study contrast media, and clinical events were monitored by an independent nurse for 1 month. Results. Patients receiving the ionic media were significantly less likely to experience decreased blood flow during the procedure (8.1% vs. 17.8%, p = 0.04). After the angioplasty, residual stenosis, vessel patency, the incidence of moderate to large thrombi and use of adjunctive thrombolytic therapy were similar between the two groups. However, patients receiving ionic media had fewer recurrent ischemic events requiring repeat catheterization (3.0% vs. 11.4%, p = 0.02) and repeat angioplasty during the initial hospital stay (1.0% vs. 5.8%, p = 0.06). One month after angioplasty, patients receiving ionic contrast media reported significantly fewer symptoms of any angina (8.5 vs, 20.0%, p 0.04) or of angina at rest (1.4% vs. 11.8%, p = 0.01) and a reduced need for subsequent bypass surgery (0% vs. 5.9%, p = 0.04), compared with patients receiving the nonionic media. Con Conclusions. These findings demonstrate that in patients with unstable ischemic syndromes undergoing coronary angioplasty, the use of ionic low osmolar contrast media reduces the risk of ischemic complications acutely and at 1 month after the procedure. Therefore, low osmolar ionic contrast media should be strongly considered when performing interventions in patients with unstable angina or myocardial infarction.