Plaque prolapse after stent implantation in patients with acute myocardial infarction: an intravascular ultrasound analysis

The aim of this study was to assess the incidence, predictors, and outcome of plaque prolapse (PP) after stent implantation in acute myocardial infarction. The imaging characteristics of PP in patients with acute myocardial infarction are not well known. Intravascular ultrasound (IVUS) imaging was performed in 310 patients immediately following stenting for their first acute myocardial infarction. Multiple clinical, angiographic and IVUS derived variables were compared among patients with and without intrastent PP. The PP was detected in 27% of the 310 lesions examined. Stent length was longer (31 +/- 13 mm vs. 21 +/- 8 mm, p < 0.001), and positive remodeling (48% vs. 32%, p = 0.008), plaque rupture (51% vs. 31%, p = 0.001), and thrombus (40% vs. 21%, p = 0.001) were significantly more common in PP lesions compared with non-PP lesions. The creatine kinase-myocardial band (CK-MB) was significantly greater after stenting in PP lesions compared with non-PP lesions (Delta = +12.3 +/- 32.0 U/l vs. -4.9 +/- 46.1 U/l, p = 0.002). During a 1-month follow-up, the incidence of stent thrombosis was not significantly different between PP and non-PP lesions [2/85 (2.4%) vs. 2/225 (0.9%), p = 0.308]. Multivariate analysis showed that PP (odds ratio [OR]: 7.34, p < 0.001), plaque rupture (OR: 1.95, p = 0.023), and thrombus (OR: 1.84, p = 0.026) were independently associated with post-stenting CK-MB elevation, and stent length (OR: 2.39, p = 0.003), plaque rupture (OR: 1.96, p = 0.015), and positive remodeling (OR: 1.72, p = 0.044) were independently associated with the development of PP. PP occurs in one-fourth of infarct-related arteries after stent implantation. Lesion characteristics such as plaque rupture and positive remodeling, together with longer stent predict PP. Although long-term follow-up is pending, PP is associated with more myonecrosis after stenting in patients with acute myocardial infarction.