Role of intracoronary thrombus in acute complications during percutaneous transluminal coronary angioplasty.

Coronary angiograms from 2,372 consecutive patients who underwent percutaneous transluminal coronary angioplasty (PTCA) were retrospectively reviewed for the presence of intracoronary thrombus (ICT) before dilatation. Patients with evolving acute myocardial infarction and those receiving thrombolytic therapy were excluded from analysis. Coronary artery thrombus was present in 126 patients (6%) (group 1). When compared to 2,246 patients (group 2) without ICT, group 1 had a higher incidence of unstable angina, 74% vs. 66% (less than 0.06), previous myocardial infarction, 59% vs. 37% (P less than .0001), and history of a recent myocardial infarction, 28% vs. 9% (P less than .0001). Patients with predilatation intracoronary thrombus had a higher risk for acute occlusion, 6% vs. 2% (P less than .002); however, the incidence of emergency coronary bypass surgery and myocardial infarction was similar in both groups. Therefore, the presence of predilatation intracoronary thrombus heralds an increased risk of acute occlusion, but not myocardial infarction or emergency coronary artery bypass surgery.