Stent malapposition,as a potential mechanism of very late stent thrombosis after bare-metal stent implantation: A case report

A 90-year-old man was admitted to our hospital with acute ST-segment elevation myocardial infarction. He had a history of post-infarction angina pectoris 79 months ago and had a bare-metal stent (BMS) implanted in the proximal left anterior descending artery at our hospital. Emergent coronary angiography demonstrated thrombotic occlusion in the previously stented segment. After catheter thrombectomy, antegrade flow was restored, but 90% stenosis with haziness persisted in the proximal and distal portions of the previously stented segment. Intravascular ultrasound imaging showed interstrut cavities or stent malapposition at the proximal and distal sites of stented segment. In close proximity to the sites, residual thrombi were also observed. Optical coherence tomography (OCT) demonstrated neither lipid-laden neointimal tissue nor rupture but clearly demonstrated residual thrombus adjacent to the malapposed region in addition to the stent malapposition. PCI with balloon was successfully performed and stent apposition was confirmed by OCT. Stent malapposition is an unusual mechanism of very late stent thrombosis after BMS implantation. OCT can clearly reveal the etiology of stent thrombosis.     

Erosion/malapposition of a sirolimus eluting stent – Optical coherence tomography image – A case report

The presence of erosion/malapposition of a Sirolimus eluting stent was clearly visualized using Optical Coherence Tomography (OCT) imaging. The presence of erosion/malapposition and the absence of neointimal hyperplasia after 10 months of sirolimus eluting stent could constitute a potential thrombogenic substrate for late stent thrombosis.     

支架释放同时推注造影剂评价支架术后即刻贴壁不良

目的:通过支架释放同时推注造影剂(Simultaneous injection contrast,SIC),判断支架贴壁情况与光学相干断层成像(optical coherence tomography,OCT),测量支架小梁与血管内膜之间距离,对比评价SIC方法,判断术后即刻支架贴壁情况的实用性。方法:入选21例原位病变的冠心病患者,行支架植入术的同时通过释放支架,同时推注造影剂(SIC)方法判断支架大体的贴壁情况,同时记录支架的型号释放压力等,之后用光学相干断层成像(OCT)精确判断支架的贴壁情况,并对OCT图像每隔1 mm的横截面的支架小梁的贴壁情况进行记录和分析,通过两者的结果对比,评价SIC方法在支架贴壁情况中的实用性。结果:21例患者中共植入支架34枚,其中2个支架节段用SIC及OCT判断均存在贴壁不良,11个支架节段SIC判断贴壁良好,而经OCT检查发现存在>1%的支架小梁贴壁不良。SIC和OCT检查均为贴壁良好的支架节段有21个。结论:SIC方法是在临床实践中一种简便实用的判断支架贴壁情况的方法,虽然其准确性难以与OCT相媲美,但作为一种简便经济的方法,值得在临床推广使用。     

All stent strut malappositions are not created equal

• The current meta‐analysis evaluates the relationship of late incomplete stent apposition (LISA) observed either by IVUS or OCT 6–18 months after PCI and long‐term outcomes, particularly in regard to stent thrombosis (ST) and has demonstrated a small but significant increase in ST with LISA.
• The results of the current study do not apply to acute stent malapposition whose relevance to adverse outcomes is uncertain based on current evidence and a malapposition classification based on presence, length, and severity of malapposed struts.
• A classification of stent malapposition based on cause of malapposition is proposed as a method to determine prognostic importance of acute incomplete stent apposition.

     

Immediate results of bifurcational stenting assessed with optical coherence tomography

Background : A tubular stent may adapt with difficulty to coronary bifurcation lesions (CBLs). Methods : Time domain or frequency domain (FD) optical coherence tomography (OCT) was performed to assess strut apposition immediately after stent implantation across four segments inside the bifurcation, in a consecutive series of patients. OCT pullbacks were performed in the main vessel (MV). Results : A total of 13,142 struts in 45 CBL in 41 patients were assessed. Strut malapposition was significantly more frequent in the half bifurcation facing the side‐branch (SB) ostium (42.9%) than in the proximal segment of the bifurcation 11.8%, half bifurcation opposite the SB 6.7%, or the distal segment 5.7% (all P < 0.0001). Lesions (n = 15) treated with stenting of both MV and SB had a total higher rate of malapposition than those (n = 30) treated with stenting of the MV only (17.6% vs. 9.5%; P = 0.0014). In latter group, lesions treated with FD‐OCT‐guided stent implantation (n = 13) presented a lower rate of malapposition than those treated with conventional angiographic‐guided stent implantation (n = 17) (7.1% vs. 17.5%; P = 0.005). Conclusions : In CBL, strut malapposition is particularly high at the SB ostium. However, a strategy of stenting MV only with adjunctive FD‐OCT guidance is associated with lower rates of malapposition. © 2012 Wiley Periodicals, Inc.     

光学相干断层成像评价药物洗脱支架置入术后晚期支架贴壁不良

目的 探讨药物洗脱支架(DES)置入术后晚期支架贴壁不良的特点.方法 分析32例(包括51支血管、共置入71个支架)置入DES 1年后[(14.8±5.2)个月]行光学相干断层成像(OCT)检查的患者资料,对支架节段的OCT图像每间隔0.5 mm取1帧图像进行分析,找出贴壁不良的支架金属结构,测量支架到参照血管内壁的距离及支架表面内膜厚度,分析晚期支架贴壁不良的特点.结果 OCT检查在7例(21.9%)患者中检出支架贴壁不良,其中4例合并支架段血管的正性重构,1例重叠置入支架,2例发现由血栓覆盖支架金属结构,7例患者随访期间无心脏不良事件发生.97.6%的支架金属结构完全贴壁并不同程度的内膜覆盖,2.4%的支架金属结构贴壁不良,包括1.2%的支架金属结构位于血管分支开口.位于血管分支开口的支架金属结构与其他贴壁不良支架表面的内膜覆盖厚度差异无统计学意义[(0.06±0.05)mm比(0.05±0.03)mm,P>0.05].绪论晚期支架贴壁不良见于DES置入最初的贴壁不良、血管壁正性重构、重叠置入支架以及支架金属结构位于分支血管开口;贴壁不良的支架金属结构表面亦有不同程度的内膜覆盖.     

Clinical Implications of Poststent Optical Coherence Tomographic Findings: Severe Malapposition and Cardiac Events

ObjectivesThis study sought to evaluate the impact of poststent optical coherence tomography (OCT) findings, including severe malapposition, on long-term clinical outcomes.BackgroundSuboptimal OCT findings following percutaneous coronary intervention (PCI) are highly prevalent; however, their clinical implications remain controversial.MethodsOf the patients registered in the Yonsei OCT registry, a total of 1,290 patients with 1,348 lesions, who underwent OCT immediately poststenting, were consecutively enrolled for this study. All patients underwent implantation of drug-eluting stents. Poststent OCT findings were assessed to identify predictors of device-oriented clinical endpoints (DoCE), including cardiac death, target vessel-related myocardial infarction (MI) or stent thrombosis, and target lesion revascularization (TLR). Significant malapposition criteria associated with major safety events (MSE) were also investigated, such as cardiac death, target vessel-related MI, or stent thrombosis.ResultsThe median follow-up period was 43.0 months (interquartile range [IQR] 21.4 to 56.0 months). The incidence rates of stent edge dissection, tissue prolapse, thrombus, and malapposition after intervention were not associated with occurrence of DoCE. However, patients with significant malapposition (total malapposition volume [TMV] ≥7.0 mm³] exhibited more frequent MSE. A smaller minimal stent area (MSA) was identified as an independent predictor for DoCE (hazard ratio [HR]: 1.20 [95% confidence interval [CI]: 1.00 to 1.43]; p = 0.045). Malapposition with TMV ≥7.0 mm³ was found to be an independent predictor of MSE (HR: 6.12 [95% CI: 1.88 to 19.95]; p = 0.003). Follow-up OCT at 3, 6, or 9 months after PCI showed that poststent TMV ≥7.0 mm³ was related to a greater occurrence of late malapposition and uncovered struts.ConclusionsAlthough most suboptimal OCT findings were not associated with clinical outcomes, a smaller MSA was associated with DoCE, driven mainly by TLR, and significant malapposition with TMV ≥7.0 mm³ was associated with more MSE after PCI. (Yonsei OCT [Optical Coherence Tomography] Registry for Evaluation of Efficacy and Safety of Coronary Stenting; Yonsei OCT registry; NCT02099162)     

Optical coherence tomography analysis of the stent strut and prediction of resolved strut malapposition at 3 months after 2nd-generation drug-eluting stent implantation

Our objective was to clarify whether thrombogenic problems with stent struts are resolved at 3 months after 2nd-generation drug-eluting stent implantation. Twenty-one patients with stable angina pectoris having 28 (22 zotarolimus-eluting, 6 everolimus-eluting) stents with optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI) were evaluated. Stent strut coverage and malapposition were evaluated by OCT immediately after PCI and at 3-month follow-up. Acute strut malapposition was observed in 26 out of 28 analyzed stents (92.9 %). At 3-month follow-up, 7 (26.9 %) of those 26 stents with strut malapposition were completely resolved, and the mean percentages of uncovered struts and malapposed struts were 8.3 and 2.0 % when analyzed by each individual stent. When analyzing a total of 30,060 struts, 807 struts (2.7 %) demonstrated acute strut malapposition. Among these, 219 struts (27.1 %) demonstrated persistent strut malapposition. On the basis of receiver-operating characteristic curve analysis, a strut-to-vessel (S-V) distance ≤160 µm on post-stenting OCT images was the corresponding cutoff point for resolved malapposed struts (sensitivity 78.1 %, specificity 62.8 %, area under the curve 0.758). The S-V distance of persistent malapposed struts on post-stenting OCT images was longer than that of resolved malapposed struts (235 ± 112 vs. 176 ± 93 µm, p < 0.01). At 3 months after PCI, the prevalence rates of uncovered and malapposed struts were relatively low in 2nd-generation drug-eluting stent. Our results suggest that OCT-guide PCI with an S-V distance ≤160 µm may be recommended especially in patients with planed short-term DAPT.     

光学相干断层扫描在冠脉介入治疗方面的发展现状

光学相干断层扫描是迄今为止被认为最有效的辨认易损斑块形态及评估支架术后内膜覆盖程度的工具。光学相干断层扫描可用于指导支架植入，评价支架内膜增生情况，探讨支架内再狭窄的原因，检出支架晚期贴壁不良和支架内血栓形成等方面。     

OCT对于DES术后晚期或晚晚期血栓治疗的指导作用

目的 观察光学相干断层成像（OCT）技术对于药物洗脱支架（DES）术后发生晚期或晚晚期血栓治疗对策的指导作用.方法 选取2010年7月至2013年11月本院收治的行DES支架置入术后发生晚期或晚晚期支架内血栓患者22例,对患者行OCT检查,根据OCT结果采取进一步治疗措施.结果 DES术后晚期或晚晚期血栓的OCT表现为：支架内皮化不全6例、贴壁不良12例、支架内新生动脉粥样硬化斑块形成8例,支架内纤维过度增生较为少见2例,有些患者上述情况同时存在.治疗对策：单纯支架内皮化不全及支架贴壁不良者采取单纯球囊扩张术12例,新生动脉粥样硬化斑块形成或纤维过度增生者采取球囊扩张加支架置入术10例.结论 OCT可以准确了解DES术后晚期或晚晚期血栓的原因,提供更为合适的治疗方案.     

光学相干断层成像评价植入不同药物洗脱支架后的血管愈合情况

目的应用光学相干断层成像（OCT）比较急性心肌梗死（AMI）患者植入不同药物洗脱支架（DES）后的新生内膜覆盖和支架贴壁情况以评估血管愈合。方法 49例AMI患者植入不同DES后9个月时进行OCT检查。其中20个雷帕霉素药物洗脱支架（SES,Cypher）,12个紫杉醇药物洗脱支架（PES,Taxus）和17个雷帕霉素衍生物药物洗脱支架（ZES,Endeavor）。每隔1mm评估OCT横断面影像每个支架柱的新生内膜覆盖和贴壁情况,同时观察每个支架内的血栓发生情况。结果总计对12378个支架柱进行了分析。SES的新生内膜增生最少,新生内膜厚度：SES（77±60）μm、PES（153±82）μm、ZES（265±130）μm,且新生内膜增生面积百分比最低,SES（10±8）%、PES（19±8）%、ZES（28±9）%,但SES和PES有更多未被新生内膜覆盖的支架柱,SES（15.1±16）%、PES（7.1±10）%、ZES（0.6±1.5）%,且贴壁不良支架柱的发生率也高于ZES,SES（3.8±7.2）%、PES（2.1±4.4）%、ZES（0±0）%,而有完全新生内膜覆盖的支架比例以ZES为高,SES5%、PES33.3%、ZES82.4%。血栓的发生率SES和PES高于ZES,SES34%、PES33%、ZES6%。结论 AMI患者植入不同类型DES后,其支架的新生内膜覆盖程度和贴壁不良的发生率是显著不同的,因此DES的类型可能影响了AMI血栓性病变的血管愈合过程。     

Comparison of Stent Expansion Guided by Optical Coherence Tomography Versus Intravascular Ultrasound: The ILUMIEN II Study (Observational Study of Optical Coherence Tomography [OCT] in Patients Undergoing Fractional Flow Reserve [FFR] and Percutaneous Coronary Intervention)

ObjectivesThe present study sought to determine whether optical coherence tomography (OCT) guidance results in a degree of stent expansion comparable to that with intravascular ultrasound (IVUS) guidance.BackgroundThe most important predictor of adverse outcomes (thrombosis and restenosis) after stent implantation with IVUS guidance is the degree of stent expansion achieved.MethodsWe compared the relative degree of stent expansion (defined as the minimal stent area divided by the mean of the proximal and distal reference lumen areas) after OCT-guided stenting in patients in the ILUMIEN (Observational Study of Optical Coherence Tomography [OCT] in Patients Undergoing Fractional Flow Reserve [FFR] and Percutaneous Coronary Intervention) (N = 354) and IVUS-guided stenting in patients in the ADAPT-DES (Assessment of Dual Antiplatelet Therapy With Drug-Eluting Stents) study (N = 586). Stent expansion was examined in all 940 patients in a covariate-adjusted analysis as well as in 286 propensity-matched pairs (total N = 572).ResultsIn the matched-pair analysis, the degree of stent expansion was not significantly different between OCT and IVUS guidance (median [first, third quartiles] = 72.8% [63.3, 81.3] vs. 70.6% [62.3, 78.8], respectively, p = 0.29). Similarly, after adjustment for baseline differences in the entire population, the degree of stent expansion was also not different between the 2 imaging modalities (p = 0.84). Although a higher prevalence of post-PCI stent malapposition, tissue protrusion, and edge dissections was detected by OCT, the rates of major malapposition, tissue protrusion, and dissections were similar after OCT- and IVUS-guided stenting.ConclusionsIn the present post-hoc analysis of 2 prospective studies, OCT and IVUS guidance resulted in a comparable degree of stent expansion. Randomized trials are warranted to compare the outcomes of OCT- and IVUS-guided coronary stent implantation.     

Persistent malapposition after implantation of sirolimus-eluting stent into intramural coronary hematoma: optical coherence tomography observations.

A 76-year-old man presented with an anterior myocardial infarction. Coronary angiography showed 99% stenosis in the left anterior descending artery and total occlusion in the left circumflex artery (LCX). After successful percutaneus coronary intervention (PCI) for segment 7, a staged PCI to the LCX with a distal protection system was attempted, but the wire entered the subintima, creating a large dissection and intramural hematoma. Three sirolimus-eluting stents (SES) were implanted to cover the entire hematoma, but 2 weeks later intravascular ultrasound revealed stent malapposition, with healing of the residual hematoma, and vessel enlargement. Optical coherence tomography (OCT) showed the malapposition more clearly. Balloon dilatation successfully achieved apposition of the SES to the vessel wall, but 6 months later it revealed recurrence of malapposition, with the struts covered by thrombus-like tissue. This case suggests that SES implantation treatment of a long intramural hematoma can potentially cause late malapposition because of persistent vessel enlargement related to arterial wall injury and inhibition of neointimal hyperplasia by the SES. OCT is useful in showing the precise condition of the stent struts.     

Optical coherence tomography guided PCI – Initial experience at Apollo Health City,Jubilee Hills,Hyderabad

Background

The capability of OCT to examine the structure of the arterial wall before or after PCI is superior to those of other imaging modalities. Therefore the application of OCT during PCI seems logical and has the potential to enhance our performance during the PCI procedures.

Methods

OCT was performed in fifty-two patients out of which, 45 patients underwent PCI. Out of these 45 patients, in 25 patients both pre and post PCI OCT assessment was done. In 20 patients only post PCI OCT assessment was done. In seven patients PCI was not done due to nonsignificant obstruction, these seven patients were not included in final analysis.

Results

Over all OCT leads to management changes in 65% of the time it was used. Alteration of stent length was done in 56% of the cases when evaluated pre PCI. Alteration of stent diameter was done in 36% cases when evaluated pre PCI. Treatment of malapposition was done in 24% of total cases. Further balloon dilatation for vessel expansion was done in 15% of total cases. In one case left main stenting was done after proximal edge dissection.

Conclusion

OCT makes better visualization of plaque, thrombus, stent malapposition, dissection, plaque prolapse and helps in optimization of PCI results. More extensive, long-term studies will be needed to assess the prognostic implications of these findings.     

光学相干断层成像在冠心病诊治中的进展

光学相干断层成像分辨率高,可用于冠状动脉粥样硬化斑块性质的确定和易损斑块的发现,并且可用于分析支架内膜的覆盖率和支撑杆的贴壁情况,指导支架的释放。近年取得了快速的发展。本文将对这一方面做一综述。     

A self-expandable coronary stent system to treat complex coronary stenosis complicated by poststenotic aneurysm: an optical coherence tomographic evidence-based case report

Coronary artery aneurysm is a relatively uncommon disorder characterized by coronary artery dilatation with diameter that exceeds 50% of the normal adjacent segments with atherosclerosis being the most common etiology. Aneurysms can be adjacent to a stenosis in a post- or prestenotic location. Both anatomical conditions are technically challenging regarding their percutaneous treatment because of the large discrepancy in size between the stenotic and dilated segments, and require careful choice of the most appropriate technique and device. We have successfully treated a coronary stenosis complicated by a poststenotic aneurysm in a 60-year-old patient with atypical angina using a novel self-expandable coronary stent system implanted with optical coherence tomography (OCT) guidance. OCT scan after implantation showed residual stent malapposition inside the aneurysm despite postdilatation. Thanks to the ability of this stent to self-expand over time, 6-month OCT follow-up showed an optimal result in terms of stent apposition, strut coverage, and absence of in-stent restenosis.     

Apport de l’imagerie endocoronaire dans le syndrome coronarien aigu

Acute coronary syndrome (ACS) remains a major cause of mortality and morbidity in the world, although it has considerably decreased through technical and pharmacological advances. The physiopathological approach of the ACS has progressed considerably in recent years thanks to the anatomopathological work and the data of the endocoronary imaging, in particular of the endovascular ultrasound (IVUS). Plaque rupture is the most common cause of ACS, however OCT (optical coherence tomography) studies have shown that surface plaque erosion was more common than thought. The use of OCT in the ACS may prove to be a valuable diagnostic aid: study of the culpable lesion, spontaneous coronary dissection or intramural spontaneous hematoma, stent thrombosis; from a therapeutic point of view: reduction of the risk of stent malapposition, additional technique, delayed stenting, implantation of a bioresorbable stent, medical treatment of ACS without stenting. Endocoronary imaging, especially OCT, will of course never be systematic as treatment of ACS, but providing excellent value for both diagnosis and treatment, it must be an integral part of the therapeutic arsenal available in cathlab.     

Impact of Intracoronary Optical Coherence Tomography in Routine Clinical Practice: A Contemporary Cohort Study

Background/purposeGuidelines recommend intracoronary optical coherence tomography (OCT) to assess stent failure and guide percutaneous coronary intervention (PCI) but OCT may be useful for other indications in routine clinical practice.Methods/materialsWe conducted an international registry of OCT cases at two large tertiary care centers to assess clinical indications and the potential impact on decision making of OCT in clinical routine. Clinical indications, OCT findings, and their impact on interventional or medical treatment strategy were retrospectively assessed.ResultsOCT was performed in 810 coronary angiography cases (1928 OCT-pullbacks). OCT was used for diagnostic purposes in 67% (N = 542) and OCT-guided percutaneous coronary intervention in 50% (N = 404, 136 cases with prior diagnostic indication). Most frequent indications for diagnostic OCT were culprit lesion identification in suspected ACS (29%) and stent failure assessment (28%). OCT findings in the diagnostic setting influenced patient management in 74%. OCT-guided PCIs concerned ACS patients in 45%. Among the 55% with chronic coronary syndrome, long lesions >28 mm (19%), left main PCI (16%), and bifurcation PCI with side-branch-stenting (5%) were the leading indications for PCI-guidance. Post-procedural OCT findings led to corrective measures in 52% (26% malapposition, 14% underexpansion, 6% edge dissection, 3% intrastent mass, 3% geographic plaque miss).ConclusionsOCT was most frequently performed to identify culprit lesions in suspected ACS, for stent failure assessment, and PCI-guidance. OCT may impact subsequent treatment strategies in two out of three patients.     

Influence of Plaque Characteristics on Early Vascular Healing in Patients With ST-Elevation Myocardial Infarction

ObjectivesTo compare the early vascular healing of ruptured plaques (RP) and non-ruptured plaques (NRP) one month after primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI), using optical coherence tomography (OCT).BackgroundVascular healing and strut coverage are important factors in reducing the risk of stent thrombosis after PCI. Influence of underlying lesion characteristics and differences in healing response between RP and NRP are unknown.MethodsTwenty-six STEMI-patients underwent PCI and implantation of a polymer-free drug-coated Biofreedom stent (BF-BES). OCT was performed pre-PCI, post-PCI and at 1-month follow-up. The patients were divided into two groups: RP = 15 and NRP = 11. OCT analyses of culprit lesion, post stent implantation at baseline and follow-up were performed to determine the difference in vascular healing based on presence of uncovered and/or malapposed stent struts and intraluminal filling defects.ResultsThe stent coverage did not differ significantly between the two groups at 1-month follow-up with percentage of uncovered struts: RP 26.5% [IQR 15.0–49.0] and NRP 28.1% [IQR 15.5–38.8] for NRP (p = 0.78). At 1-month, RP showed an increased percentage of late acquired malapposed struts (1.4% [IQR 0.8–2.4] vs. 0.0% [IQR 0.0–1.4], p = 0.03) and a larger total malapposition area (1.3 mm² [IQR 0.4–2.5] vs. 0.0 mm² [IQR 0.0–0.9], p = 0.01), compared to NRP.ConclusionThree out of four struts were covered within one month after stenting. The vascular healing was comparable in RP and NRP on stent coverage. However, RP had more and larger late acquired malapposition areas.     

Incidence and mechanism of late stent malapposition after phosphorus-32 radioactive stent implantation

Late stent malapposition is a potential complication of intracoronary brachytherapy. The aim of our study was to determine the incidence and mechanism of late stent malapposition after implantation of phosphorus-32 radioactive stents. We analyzed 159 patients for de novo lesions after the implantation of phosphorus-32 radioactive stents. There were 15 late stent malappositions. The incidence of malapposition was higher in patients who received Hot-Ends Isostents. External elastic membrane expansion greater than plaque increase in malapposed segments was observed. Late stent malapposition is caused by a localized increase in external elastic membrane that is greater than the increase in plaque area; this is believed to be a dose-dependent phenomenon because it was more common with Hot-Ends Isostents.