Yuki Haruhito, Naganuma Toru, Nakazawa Gaku, Nakamura Sunao
Division of Cardiovascular Medicine, New Tokyo Hospital, 1271 Wanagaya, Matsudo, Chiba 270-2232, Japan.
Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
Eur Heart J Case Rep. 2021 Feb 28;5(3):ytaa572. doi: 10.1093/ehjcr/ytaa572. eCollection 2021 Mar.
Late catch-up phenomenon following stent implantation is a well-known complication. However, no report has evaluated thrombosis after 9 years with multi-modality and pathological evaluation.
A 71-year-old man with stable angina underwent elective percutaneous intervention of the left main coronary artery with implantation of a bare metal stent (BMS) 9 years ago. At the 9-year follow-up, coronary computed tomography (CCT) and coronary angiography (CAG) findings revealed a thrombus-like structure in the BMS slightly protruding into the sinus of Valsalva. Therefore, the previously prescribed double-antiplatelet therapy was replaced with an anticoagulant and clopidogrel, and a potent statin treatment was initiated. After the changes in drug treatment, follow-up examinations with CCT at 1 and 3 months suggested a decrease in the size of the thrombus; however, it appeared to increase after 6 months. Subsequently, the patient underwent surgical intervention. Pathological assessment of the explanted stent showed a proteoglycan-dominated extracellular matrix with few smooth muscle cells suggesting an organized thrombus.
It should be emphasized that multiple factors might be responsible for very late stent thrombosis, such as peri-stent strut chronic inflammation involving proteoglycans, stent protrusion, and poorly controlled type 2 diabetes mellitus, possibly further inducing inflammatory cells.
支架植入后的晚期追赶现象是一种众所周知的并发症。然而，尚无报告通过多模态和病理学评估对9年后的血栓形成情况进行评估。
一名71岁稳定型心绞痛男性患者于9年前接受了左主干冠状动脉选择性经皮介入治疗并植入了裸金属支架（BMS）。在9年随访时，冠状动脉计算机断层扫描（CCT）和冠状动脉造影（CAG）结果显示BMS内有一个血栓样结构，略突出至主动脉窦。因此，将先前规定的双联抗血小板治疗换成了抗凝剂和氯吡格雷，并开始强化他汀类药物治疗。在药物治疗改变后，1个月和3个月时的CCT随访检查提示血栓大小减小；然而，6个月后似乎又增大了。随后，患者接受了手术干预。取出支架的病理评估显示，以蛋白聚糖为主的细胞外基质中平滑肌细胞很少，提示为机化血栓。
应强调的是，多种因素可能导致极晚期支架血栓形成，如涉及蛋白聚糖的支架支柱周围慢性炎症、支架突出以及2型糖尿病控制不佳，可能进一步诱导炎症细胞。
