Identification of Intrastent Pathology Associated With Late Stent Thrombosis Using Optical Coherence Tomography

OBJECTIVE: To better characterize intrastent pathology using optical coherence tomography (OCT) in patients presenting with late and very late stent thrombosis (LST/VLST). BACKGROUND: The contribution of specific intrastent pathologies to the development of LST/VLST is not well understood. METHODS: In this single-center, retrospective, observational study of 796 consecutive patients treated for ST-segment elevation myocardial infarction (STEMI) with primary PCI we identified 57 patients (7.2%) in whom STEMI resulted from LST/VLST. Of the patients with LST/VLST, 21 patients (37%) had OCT performed at the discretion of the operator during PCI for LST/VLST. Independent reviewers performed qualitative offline analysis of OCT images to determine the cause of stent thrombosis defined as the specific intrastent pathology associated with thrombus deposition. RESULTS: The principal intrastent pathology causing LST/VLST was determined to be stent malapposition in 11 patients (55%), of which 5 (25% of all LST/VLST patents) had findings suggestive of positive vessel remodeling. Neoatherosclerosis was determined to be the cause of LST/VLST in 7 patients (35%). LST/VLST resulted from uncovered stent struts in 2 patients (10%). Among all LST/VLST patients, in-hospital mortality (12.3%) and post-hospital target vessel failure (TVF) or cardiac death (21.7%, median follow-up 1.6 years) remained high. There was a trend towards decreased TVF or cardiac death (7.7% vs. 27.3% P = 0.24) in patients who underwent OCT-guided therapy. CONCLUSIONS: LST/VLST remains a significant cause of STEMI and is associated with considerable morbidity and mortality. OCT use at the time of PCI consistently identifies significant intrastent pathology with potentially meaningful clinical impact.