Optical Frequency Domain Imaging of Very Late Stent Thrombosis Following Bare-Metal Stent Implantation for Acute Myocardial Infarction

Abstract

SummaryA 43-year-old man was admitted to our hospital with ST-segment elevation acute coronary syndrome. He had experienced myocardial infarction 19 months previously, and a bare-metal stent (BMS) had been implanted in the culprit distal right coronary artery at another hospital. Emergency coronary angiography showed thrombotic in-stent occlusion of the BMS. Intravascular ultrasound revealed an undersized stent compared with the size of the vessel and late stent malapposition (LSM) with abundant thrombi. The lesion was successfully recanalized via thrombectomy and plain old balloon angioplasty. Optical frequency domain imaging performed at follow-up coronary angiography confirmed the improvement of the LSM and incomplete neointimal stent coverage. This report illustrates the importance of imaging modalities in elucidating the mechanism of BMS-related very late stent thrombosis.(Int Heart J 2018; 59: 209-212) Key words: Acute coronary syndrome, Incomplete neointimal stent coverage, Late stent malapposition A lthough very late stent thrombosis (VLST) following bare-metal stent (BMS) implantation is a rare phenomenon, it causes severe complications once it occurs. Neoatherosclerosis plays an important role in BMS-related VLST, especially in elective cases. 1,2) However, in cases of acute coronary syndrome, late stent malapposition (LSM) is the primary mechanism behind BMS-related VLST, as confirmed by intravascular ultrasound (IVUS) imaging.3) In clinical settings, however, detailed image analysis using optical frequency domain imaging (OFDI) has rarely been reported. In the present case, IVUS and OFDI images of BMS-related VLST revealed an undersized stent with LSM and possibly incomplete neointimal stent coverage, even after 19 months following the initial BMS implantation for acute coronary syndrome. Case ReportA 43-year-old man was admitted to our hospital with sudden chest pain. The patient had coronary risk factors including dyslipidemia and current smoking. He had experienced myocardial infarction 19 months previously and undergone percutaneous coronary intervention (PCI) in the distal right coronary artery (RCA) with a BMS (Multi-link Vision 2.5/23 mm, Abbot Vascular, Santa Clara, USA) at another hospital. At the same time, an additional BMS (Multi-link Vision 3.5/23 mm, Abbot Vascular) was implanted for 75% stenosis in the mid-RCA. Final IVUS confirmed optimal stent expansion to the normal size with well-apposed stent struts in both stents. He was discharged on dual antiplatelet therapy (acetylsalicylic acid 100 mg and clopidogrel 75 mg once daily). The clopidogrel was discontinued 12 months after the initial PCI.On admission, electrocardiography showed STsegment elevation in the inferior leads. Emergency coronary angiography revealed total thrombotic in-stent occlusion at the distal RCA (Figure 1). A 6-Fr guiding catheter (Mach-1 FR 3.5, Boston Scientific, Natick, MA, USA) was engaged into the RCA, and thrombectomy was performed with an aspiration catheter (Thrombuster SLIII , Kaneka, Osaka, Japan). After...