Prevalence, distribution, predictors, and outcomes of patients with calcified nodules in native coronary arteries: A 3-vessel intravascular ultrasound analysis from providing regional observations to study predictors of events in the coronary tree (PROSPECT)

Background-Pathological studies suggest that calcified coronary nodules are a rare cause of thrombotic events. The frequency, distribution, predictors, and outcomes of calcified nodules have never been described. Methods and Results-After successful stenting in 697 patients (167 female; median age, 58.1 years) with acute coronary syndromes, 3-vessel gray-scale and virtual histology intravascular ultrasound was performed in the proximal-mid segments of all 3 coronary arteries as part of a prospective, multicenter study. On the basis of recent histological validation, an independent core laboratory identified calcified nodules as distinct calcification with an irregular, protruding, and convex luminal surface. Patients were followed up for 3 years (median). Overall, 314 calcified nodules were detected in 250 of 1573 analyzable arteries (185 of 623 patients). Thus, the prevalence of calcified nodules was 17% per artery and 30% per patient. Two or more calcified nodules were detected in 48 coronary arteries (3%) in 76 patients (12%). The calcified nodules were located <40 mm from the ostium of the coronary artery in 85% of left anterior descending arteries and 86% of left circumflex arteries, whereas calcified nodules within the right coronary arteries were evenly and more distally distributed. Patients with calcified nodules were significantly older and had more plaque volume, more thick-cap fibroatheroma, but fewer nonculprit lesion major adverse events on follow-up. Conclusions-Calcified nodules in untreated nonculprit coronary segments in patients with acute coronary syndromes were more prevalent than previously recognized. Although their distribution mirrored the origin of most thrombotic events, calcified nodules caused fewer major adverse events during 3 years of follow-up.