Influence of contrast media on thrombus formation during coronary angioplasty.

The influence of contrast media on thrombus formation during percutaneous transluminal coronary angioplasty was assessed in 124 consecutive patients undergoing coronary angioplasty and receiving either ionic (n = 57) (Group I) or nonionic (n = 67) (Group II) contrast medium. The presence of thrombus was assessed by qualitative analysis of angiograms in identical pre- and postangioplasty projections by four observers who had no knowledge of other data. Quantitation of stenosis severity before and after angioplasty and qualitative analysis of lesion eccentricity and complexity and of the presence of dissection were also performed. Although the baseline clinical characteristics of the two groups (including presenting syndromes and procedural and angiographic variables) did not differ, more patients in Group II than Group I developed new thrombus during coronary angioplasty (18% vs. 4%, p less than 0.02). In particular, patients with a presenting syndrome of recent myocardial infarction or rest angina, or both, and patients with an eccentric coronary plaque were more likely to develop new thrombus if they received nonionic than if they received ionic contrast medium (p less than 0.05). Patients with new thrombus formation and patients with thrombus present both before and after angioplasty had a high incidence of acute procedural complications (36% and 23%, respectively). Patients in Groups I and II had a similar incidence of ischemic events during follow-up.