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.