Background: Stent thrombosis (ST) is a serious complication following coronary stenting. Intravascular optical coherence tomography (OCT) may provide insights into mechanistic processes leading to ST. We performed a prospective, multicenter study to evaluate OCT findings in patients with ST.

Methods: Consecutive patients presenting with ST were prospectively enrolled in a registry by using a centralized telephone registration system. After angiographic confirmation of ST, OCT imaging of the culprit vessel was performed with frequency domain OCT. Clinical data were collected according to a standardized protocol. OCT acquisitions were analyzed at a core laboratory. Dominant and contributing findings were adjudicated by an imaging adjudication committee.

Results: Two hundred thirty-one patients presenting with ST underwent OCT imaging; 14 (6.1%) had image quality precluding further analysis. Of the remaining patients, 62 (28.6%) and 155 (71.4%) presented with early and late/very late ST, respectively. The underlying stent type was a new-generation drug-eluting stent in 50.3%. Mean reference vessel diameter was 2.9±0.6 mm and mean reference vessel area was 6.8±2.6 mm². Stent underexpansion (stent expansion index <0.8) was observed in 44.4% of patients. The predicted average probability (95% confidence interval) that any frame had uncovered (or thrombus-covered) struts was 99.3% (96.1–99.9), 96.6% (92.4–98.5), 34.3% (15.0–60.7), and 9.6% (6.2–14.5) and malapposed struts was 21.8% (8.4–45.6), 8.5% (4.6–15.3), 6.7% (2.5–16.3), and 2.0% (1.2–3.3) for acute, subacute, late, and very late ST, respectively. The most common dominant finding adjudicated for acute ST was uncovered struts (66.7% of cases); for subacute ST, the most common dominant finding was uncovered struts (61.7%) and underexpansion (25.5%); for late ST, the most common dominant finding was uncovered struts (33.3%) and severe restenosis (19.1%); and for very late ST, the most common dominant finding was neoatherosclerosis (31.3%) and uncovered struts (20.2%). In patients presenting very late ST, uncovered stent struts were a common dominant finding in drug-eluting stents, and neoatherosclerosis was a common dominant finding in bare metal stents.

Conclusions: In patients with ST, uncovered and malapposed struts were frequently observed with the incidence of both decreasing with longer time intervals between stent implantation and presentation. The most frequent dominant observation varied according to time intervals from index stenting: uncovered struts and underexpansion in acute/subacute ST and neoatherosclerosis and uncovered struts in late/very late ST.

背景：冠状动脉支架置入术是支架内血栓形成（ST）的严重并发症。血管内光学相干断层扫描（OCT）可能提供导致ST的机械过程的见解。我们进行了一项前瞻性，多中心研究，以评估ST患者的OCT结果。

方法：使用集中式电话注册系统，对患有ST的连续患者进行前瞻性登记。在对ST进行血管造影确认后，使用频域OCT对罪犯血管进行OCT成像。根据标准化方案收集临床数据。在一个核心实验室对OCT的购置进行了分析。成像裁决委员会对主要和有贡献的发现进行裁决。

结果： 2131例ST患者接受了OCT成像。14名（6.1％）的图像质量无法进行进一步分析。在其余患者中，分别有62例（28.6％）和155例（71.4％）出现早期和晚期/非常晚期ST。潜在的支架类型为50.3％的新一代药物洗脱支架。参考血管平均直径为2.9±0.6 mm，参考血管平均面积为6.8±2.6 mm ²。在44.4％的患者中观察到支架扩张不足（支架扩张指数<0.8）。未发现任何帧（或血栓覆盖）的支撑的预测平均概率（95％置信区间）为99.3％（96.1-99.9），96.6％（92.4-98.5），34.3％（15.0-60.7）和9.6％对于急性，亚急性，晚期和极重度（6.2–14.5）和支配不良的撑杆分别为21.8％（8.4–45.6），8.5％（4.6–15.3），6.7％（2.5–16.3）和2.0％（1.2–3.3） ST晚期。急性ST的最常见的主要发现是未发现撑杆（占病例的66.7％）。对于亚急性ST，最常见的显性发现是未发现撑杆（61.7％）和扩张不足（25.5％）；对于ST晚期，最常见的显性发现是未发现撑杆（33.3％）和严重的再狭窄（19.1％）；在ST很晚的时候，最常见的显性发现是新动脉粥样硬化（31。3％）和裸露的支撑杆（20.2％）。在表现为ST晚期的患者中，未覆盖的支架撑杆是药物洗脱支架的常见主要发现，而新动脉粥样硬化则是裸金属支架的常见主要发现。

结论：在ST患者中，经常观察到裸露的支杆和畸形的支杆，随着支架置入和出诊之间的时间间隔的增加，支杆的发生率降低。最频繁的显性观察随指标置入支架的时间间隔的不同而变化：急性/亚急性ST和新动脉粥样硬化中未发现支撑物和扩张不足，ST中晚期/非常晚时未发现支撑物。