Abstract 4182: Unhealed Plaque Ruptures After Stenting in Acute Myocardial Infarction Assessed by Intracoronary Optical Coherence Tomography: Incidence, Predictors, and Clinical Implication
Backgrounds: Non healing after stenting a ruptured thin capped fibroatheroma in acute myocardial infarction (AMI) has been suggested to be a possible cause of late stent thrombosis. Optical coherence tomography (OCT) provides detailed information of ruptured plaques and stent strut coverage. We used OCT to assess the incidence, predictors, and implications of residual plaque rupture after stenting in AMI.
Methods: The HORIZONS-AMI trial was a prospective, multicenter, dual arm factorial trial in which pts with AMI were randomized to different antithrombotic regimens and paclitaxel-eluting TAXUS stents vs. bare metal EXPRESS stents (3:1). Clinical follow-up was performed at 12 months, and angiographic follow-up at 13 months. From this trial, 118 pts who underwent OCT at 13-month follow-up after stent implantation were enrolled in a formal substudy.
Results: Unhealed plaque rupture - defined by the persistence of core cavity in the stented segment - was observed in 13 (11.0%) pts. The incidence of residual plaque rupture was not significantly different between TAXUS (12.4 %) and EXPRESS (6.9 %) stent (p=0.52). Residual plaque rupture was detected more frequently in right coronary artery (RCA) than the left coronary artery (LCA), and was associated with a trend toward procedural slow flow after stenting. As measured by OCT at follow-up, the percentage of uncovered stent struts, neointimal volume, and residual thrombus was not significantly different in patients with residual vs. no residual plaque ruptures.
Conclusions: The present OCT study suggests that unhealed plaque ruptures after stenting in AMI are more common in the RCA than the LCA, may be associated with angiographic slow flow, but may not predict the degree of healing, neointimal formation, or stent thrombosis. Further studies are required to confirm these observations, and to determine the relative incidence of this phenomenon after drug-eluting compared to bare metal stents.