Coronary artery thrombus as a risk factor for acute vessel occlusion during percutaneous transluminal coronary angioplasty: improving results.

Early experience with percutaneous transluminal coronary angioplasty (from October 1979 to March 1983 inclusive) showed that pre-existing coronary artery thrombus was associated with a significant increase in the incidence of acute coronary occlusion during angioplasty. Acute occlusion occurred in 11 (73%) of 15 patients with pre-existing thrombus compared with 18 (8%) of 223 patients without thrombus. The effect of improved technology (steerable guiding systems) and altered dilatation strategy (full intravenous heparinisation for 24 hours after the procedure and more intensive use of antiplatelet medications) was studied by review of angiograms from 297 consecutive patients without evidence of acute myocardial infarction who underwent angioplasty from April 1983 to March 1985 inclusive. Coronary artery thrombus was present in 34 (11%) patients, eight (24%) of whom had complete occlusion during or immediately after the procedure compared with 34 (13%) of 263 patients without thrombus. Patients with pre-existing coronary artery thrombus continue to be at greater risk of complete occlusion than patients without thrombus, but this risk has declined significantly since the modification of the angioplasty procedure.