Section of Interventional Radiology, Department of Radiology, University of Michigan Medical School, Ann Arbor, MI.
Brown University Medical School, Providence, RI.
J Vasc Surg Venous Lymphat Disord. 2023 Jan;11(1):109-118.e2. doi: 10.1016/j.jvsv.2022.07.002. Epub 2022 Aug 9.
The objective of this study was to determine the pathologic features of venous in-stent stenosis over time occurring in bare metal stents.
Endovascular biopsy samples were obtained prospectively from venous bare metal stents implanted in 2009 through 2018. All samples were formalin-fixed, paraffin-embedded and stained with hematoxylin and eosin. Samples were examined by a cardiovascular pathologist to estimate the amount of its constituent components, which included fresh thrombus, organizing thrombus, old thrombus, or diffuse intimal thickening (DIT), and pathologic features including calcification, neovascularization, and hemosiderin deposition. This pathologic characterization was correlated with time following stent implantation to discern time-dependence of pathologic evolution of in-stent stenosis using both descriptive statistics and binary logistic regression.
A total of 254 post-stent venograms with biopsies of in-stent contents from 148 unique patients were studied. Fresh thrombus and organizing thrombus were both present across all studied time intervals. Old thrombus was seen beginning at approximately 2 weeks and DIT at approximately 4 weeks. Calcification was a rare finding encountered at later time intervals. The prevalence of each component varied with time: the probability of encountering fresh thrombus (P = .010) and organizing thrombus (P = .008) decreased over time. By contrast, the probability of finding DIT (P = .002) and calcifications (P < .001) increased over time. The presence of old thrombus, neovascularization, or hemosiderin did not demonstrate time dependence. Diffuse intimal thickening was frequently seen along with organizing thrombus as well as independently, and in many instances, these two features were directly merged.
The evolution of human venous in-stent restenosis appears to follow a time-dependent course, suggesting a possible progressive evolution from fresh and organizing thrombus to DIT. Contrasted with the literature on arterial in-stent restenosis, vein in-stent restenosis may have an increased thrombus prevalence (both organizing and old thrombus). DIT is a primary feature of late in-stent stenosis and may explain in part why many of these lesions may not respond to thrombolytic or anticoagulant treatment alone.
本研究旨在确定裸金属支架内静脉再狭窄的病理特征随时间的变化。
前瞻性地从 2009 年至 2018 年植入的静脉裸金属支架中获取血管内活检样本。所有样本均经福尔马林固定、石蜡包埋，并进行苏木精和伊红染色。由心血管病理学家检查样本，以评估其组成成分的数量，包括新鲜血栓、机化血栓、陈旧血栓或弥漫性内膜增厚（DIT），以及包括钙化、新生血管形成和含铁血黄素沉积在内的病理特征。将这种病理特征与支架植入后的时间相关联，以通过描述性统计和二项逻辑回归来辨别支架内狭窄的病理演变随时间的依赖性。
共研究了 148 例患者的 254 个支架后静脉造影和支架内内容物活检。所有研究时间间隔均存在新鲜血栓和机化血栓。陈旧血栓在大约 2 周时出现，DIT 在大约 4 周时出现。钙化是一种罕见的发现，出现在较晚的时间间隔。每个成分的患病率随时间变化：发现新鲜血栓（P=.010）和机化血栓（P=.008）的概率随时间降低。相比之下，发现 DIT（P=.002）和钙化（P ＜.001）的概率随时间增加。陈旧血栓、新生血管形成或含铁血黄素的存在不具有时间依赖性。弥漫性内膜增厚常与机化血栓一起出现，也可独立出现，在许多情况下，这两种特征直接合并。
人类静脉内支架再狭窄的演变似乎遵循时间依赖性过程，提示从新鲜和机化血栓到 DIT 可能存在逐渐演变。与动脉内支架再狭窄的文献相比，静脉内支架再狭窄可能具有更高的血栓发生率（包括机化和陈旧血栓）。DIT 是晚期支架内狭窄的主要特征，部分解释了为什么许多此类病变可能无法单独对溶栓或抗凝治疗产生反应。
