下肢动脉疾病应用紫杉醇载药器械后风险事件的循证进展

近年来,随着外周动脉疾病腔内治疗技术的发展,紫杉醇药物洗脱支架和药物涂层球囊广泛应用于临床,国内外的研究结果均证明紫杉醇载药器械在降低血管再狭窄方面具有良好的临床效果。然而,紫杉醇载药器械的临床安全性遭遇挑战,有研究结果表明,紫杉醇载药器械可能增加患者的远期病死率,但亦有研究结果肯定了紫杉醇载药器械的有效性和安全性,导...     

生物可降解材料聚乳酸在血管支架制备中的应用

第二代药物洗脱支架作为异物,对血管壁有长期炎症反应,这是导致支架术后远期血栓形成和支架内再狭窄的重要诱因。而生物可降解支架能克服这一缺陷。目前,生物可降解支架材料选择分为高分子聚合物材料和合金材料。在可降解高分子材料中,聚乳酸和其改性共聚物备受关注。聚乳酸是一种具有良好生物相容性和可降解性能的高分子材料,在血管支架的制备中具有广泛运用。聚乳酸既是一种很优秀的支架药物涂层的载体,也可以被开发作为支架骨架结构。     

药物涂层球囊在下肢动脉硬化闭塞症治疗中的应用现状与展望

正载药器具的出现和应用是下肢动脉腔内治疗技术发展的一个重要里程碑,包括药物涂层球囊(drug-coated balloon,DCB)和药物洗脱支架(drug-eluting stent,DES)两大类。其原理是利用载药器具携载的抗增生药物(如紫杉醇、雷帕霉素等)抑制平滑肌细胞和纤维母细胞增生,以减轻动脉内膜增生所导致的血管再狭窄。紫杉醇是细胞毒性药物,作用于细胞有丝分裂周期的M期,雷帕霉素是细胞抑制药物,可阻断G1期向S期的转化。强脂溶性     

股腘动脉疾病腔内治疗的研究进展

正股腘动脉缺血性病变的腔内治疗是近年的研究热点,随着腔内介入治疗技术的普及和介入器械的飞速发展,股腘动脉腔内治疗日趋完善。近来由于药物涂层球囊及药物洗脱支架在临床上的应用,使困扰临床多年的介入后血管再狭窄、血管闭塞的问题得到了部分解决。药物洗脱生物可吸收支架进一步展现出股腘动脉腔内治疗的曙光。     

下肢动脉硬化闭塞症治疗中载药器械应用

以药物洗脱支架和药物涂层球囊为代表的载药器械的应用,为下肢动脉硬化闭塞症的治疗提供了新的策略。围绕二者的高证据级别的临床试验也广泛开展。在对股腘动脉病变的治疗中,负载紫杉醇的药物洗脱支架及药物涂层球囊均表现出较好的一期通畅率,但在改善症状方面结果并不一致。在治疗膝下动脉病变中,药物洗脱支架的优势已基本确立,而药物涂层球囊的潜在价值尚待更多临床试验予以证实。     

生物可降解性血管内支架的研究进展

血管内支架能减少机械扩张后的血管发生急性血管闭塞和再狭窄的机会,但金属支架具有血栓源性,远期疗效不理想。载药生物可降解血管内支架既能暂时支撑管壁,保持血管通畅,又能抑制早期的血栓形成及晚期的新生内膜增生,有效防止扩张后的血管发生急性闭塞和再狭窄。本文就血管内支架的制作、形式、构成和作用进行了综述。     

血管支架内再狭窄的机理研究进展

冠状动脉粥样硬化性心脏病是引起人类死亡的重要原因之一，全世界每年经历PTCA术的患者大约有70％的人需要植入支架，但是支架内再狭窄却高达20％～30％，支架内再狭窄依然是血管支架植入的主要问题。本文综述了支架植入后再狭窄的主要病理过程，基于支架内再狭窄的具体的病理过程，大量的药物被用于治疗支架内再狭窄。本文也综述了药物涂层支架的研究现状以及存在的问题。     

药物涂层球囊治疗下肢动脉疾病研究进展

下肢动脉疾病(LEAD)是由动脉粥样硬化引起的下肢动脉管腔狭窄、闭塞,导致相应肢体出现缺血症状的一类疾病。腔内介入是治疗LEAD的主要方式,包括经皮腔内血管成型术(PTA)及支架植入术,但术后再狭窄率较高。药物涂层球囊(DCB)可在抑制血管内膜增生及炎症反应的同时避免腔内异物存留,对于原发病变及支架内再狭窄均有较好疗效。本文对DCB作用原理及其治疗LEAD应用现状和研究进展进行综述。     

下肢动脉支架内再狭窄的诊断和治疗

随着人口老龄化的加重,下肢动脉狭窄与闭塞性疾病的发生率越来越高,同时伴随着腔内支架的广泛应用,支架内再狭窄的发生率也逐渐升高。目前治疗支架内再狭窄的技术主要有药物治疗、普通球囊、药涂球囊、金属裸支架、药物洗脱支架、腔内减容（激光、旋切）和旁路搭桥术等。单一治疗方法效果均有限,而腔内减容与药涂球囊联合既可以机械去除增生的内膜,又可以有效抑制内膜再增生,是目前治疗支架内再狭窄较为合理的方法。     

下肢动脉支架内再狭窄治疗策略

下肢动脉狭窄及闭塞性病变采用支架置入已成为主流手段。由于下肢动脉独特的病变特点和生物学应力,支架置入后的再狭窄是不可回避的问题,往往需要进行二次甚至多次干预。目前对于再狭窄的治疗方法有药物治疗、球囊扩张、减容技术、再次支架置入及载药器材应用等。多数学者的研究认为球囊扩张、减容技术及再次支架置入有一定的局限性,载药器材作为新兴的腔内治疗手段,带来了新的希望。     

Comparison of long-term results of drug-eluting stent and bare metal stent implantation in heart transplant recipients with coronary artery disease

The aim of the study was to compare long-term results of intracoronary implantation of drug-eluting stents (DES) and bare metal stents (BMS) in patients suffering from transplant coronary artery disease (TxCAD). MATERIAL AND METHODS: We performed a retrospective analysis of all intracoronary stent implantations for TxCAD among subjects with at least one follow-up coronary angiography. We identified 28 sirolimus-eluting DES (n = 17) patients, 24 BMS (n = 13 patients), and both DES and BMS (n = 7 patients) implantations among 23 recipients. Mean follow-up after DES was 14 months and after BMS implantation, 20 months. We compared the occurrence of in-stent restenosis (ISR), and patient survival in the context of risk factors that were identified separately for each stent type. Significance was assessed using the log-rank, chi(2) and Mann-Whitney U test. RESULTS: There were 2 (7%) ISR among DES versus 14 (58%) ISR among BMS (P = .0002) patients, with a longer time of freedom from IRS after DES implantation (P = .022). There were three deaths (18%) among DES, four (31%) with BMS, and one (14%) with DES and BMS (P = NS). Left anterior descending artery was the place of DES implantation in 17 (61%) versus 10 (42%) of BMS cases (P = NS). Risk factor profile was comparable except for a higher age at the time of transplantation (46 +/- 7 vs 41 +/- 6 years; P = .011) and stent implantation (54 +/- 7 vs 49 +/- 6 years; P = .0002) for DES. CONCLUSION: Favorable long-term results of sirolimus-eluting stents over BMS implanted for TxCAD suggested their preferential use in heart transplant recipients.     

Clinical use of optical coherence tomography to identify angiographic silent stent thrombosis

Objectives. Patients previously treated with coronary stents may suffer an acute coronary syndrome (ACS) without any evidence of thrombus formation on coronary angiography (CAG). This may be due to partial, nonocclusive stent thrombosis with microembolization. In this paper, we illustrate possible mechanisms both with optical coherence tomography (OCT) and histology. Design. We present two cases with ACS from very late stent thrombosis who have been previously treated with first-generation drug-eluting stents (DES). Results. The first patient had ACS 15 months after DES implantation. The angiogram (CAG) was near normal with slight peri-stent contrast staining. OCT revealed abnormalities including thrombus not visible on CAG. These are findings that may explain the ACS. The second patient had subclinical episodes with chest pain after DES implantation. The patient died from stent thrombosis in a DES. Postmortem histological examination of the coronary arteries revealed stent struts with little or no neointimal coverage, persistent peri-strut fibrin deposition, inflammatory cells, malapposition, and small luminal platelet-rich thrombi. Old spotty myocardial infarctions were found in the supplied territory possibly caused by earlier episodes of embolizing thrombus. Conclusions. In patients with previous implanted DES presenting with ACS, OCT may detect abnormalities and thrombus formation not visible on CAG. Such findings may impact the treatment strategy in these patients.     

Refining stent technologies for femoral interventions

Stents were created as a mechanical scaffold to prevent vessel recoil and luminal renarrowing after percutaneous transluminal angioplasty (PTA). In femoropopliteal arteries, indication for stent implantation remains a topic much debated on, especially in long lesion configurations. Ever since the first stents were introduced on the market, in-stent restenosis (ISR) has been an important issue. The evolution in stent design has known a major progression in the last decades from the first generation of stents, plagued with high fracture rates and low primary patency rates, to the design of newer stents to tackle these outcomes. More flexible and longer stents decreased the high fracture rates and drug-eluting stents offered a solution to the restenosis rates by local drug application. The difficult recrossibility of the lesion because of the presence of a permanent vascular scaffold is an obstacle that the drug-coated balloon (DCB) overcomes. Future perspectives in the treatment of femoropopliteal lesions are found in the bioresorbable stent implantation. The bioresorbable stent combines the advantages of a drug-eluting scaffolding stent without the remainder of a foreign object in the long-term. Further investigations in this area will eventually evolve in the creation of a superior endovascular treatment modality with high long-term patency rates and minimal detriments.     

肠系膜上动脉支架植入后再狭窄诊疗的研究进展

肠系膜上动脉（SMA）出现狭窄或闭塞导致血液灌注不足,引起肠组织缺血、缺氧,最终可能导致肠黏膜损伤、肠缺血坏死。解除管腔狭窄、恢复血流是避免肠坏死的重要保障。腔内支架植入术作为一种微创治疗技术,相对于开放性血运重建,具有住院时间短,降低住院并发症及死亡风险的优势,近年来已成为治疗SMA狭窄性病变的主要治疗方式之一。因该手术方式获得了良好的近期临床治疗效果,得到指南一致推荐。随着支架在临床上广泛开展使用,SMA支架植入术后支架内再狭窄（ISR）的发生逐渐引起关注,且相关研究指出,接受支架治疗的SMA狭窄患者,相对于开放性血运重建出现ISR的概率更高。因此,SMA支架植入术后的管理显得特别重要,包括维持药物治疗以期获得支架的远期通畅性,ISR的超声及影像学检查等的早期识别和诊断,再干预治疗时机选择等。双功能超声（DUS）和SMA计算机断层扫描血管造影（CTA）检查用于ISR诊断具有较高的敏感度和特异度,目前已替代数字减影血管造影（DSA）检查成为术前诊断和筛查的首选。由于SMA缺血性病变造成的危害严重,若处理不及时可能造成肠管坏死,因此对因ISR出现相关临床症状的患者推荐尽快进行二次手术再...     

Drug-eluting stents below the knee

The fear that early thrombosis and late luminal loss due to intimal hyperplasia formation potentially leads to insufficient long-term patency rates can explain the reluctance on implanting stents in small diameter below-the-knee (BTK) arteries. Drug-eluting stent (DES) technology was developed to prevent early thrombosis and late luminal loss to potentially improve long-term patency rates. Currently, the first level 1 evidence from prospective, randomized, controlled DESTINY and ACHILLES studies indicate that the implantation of DES in short lesion lenghts in the infrapopliteal vasculature leads to favorable outcomes with high primary patency rates. This makes that primary DES placement can be recommended as treatment strategy in short BTK-lesions.     

Drug-eluting stents above the knee

There are only very few trials concerning use of drug-eluting stents (DES) in the femoropopliteal segment. While earlier trials using a sirolimus-eluting polymer-coated stent and an everolimus-eluting stent failed to demonstrate improved mid-term patency compared with a bare-metal stent, the recently presented ? however still unpublished - data with the Zilver PTX stent using a polymer-free paclitaxel coating are very promising. Before we can make definite conclusions and recommendations, we have to see longer-term follow-up data. A potential future improvement of local drug application for the necessary time span without the disadvantages of permanent stent implantation can be expected by the development of completely bioabsorbable DES.     

The impact of lesion length on angiographic restenosis after vertebral artery origin stenting.

OBJECTIVE: To evaluate the effect of lesion length on in-stent restenosis (ISR) of vertebral artery (VA) origin stenting. METHODS: We retrospectively analyzed the medical and radiological records of patients receiving VA origin stenting from March 1999 to June 2005. They were subdivided according to lesion length. ISR was defined as >50% diameter narrowing in stent. RESULTS: Eighty symptomatic patients (64 male, mean age 72 years) with 90 lesions treated with balloon expandable tubular coronary stents were enrolled. There were 34 patients with 38 short lesions (length5 mm, <10 mm, group 2) and 9 patients with 10 long lesions (length>or=10 mm, group 3). Eighty seven bare-metal stents and 3 drug-eluting stents were implanted. Repeat angiography was done in 40 lesions (44%) at 11.7+/-9.6 months. The ISR rate in group 1, 2, 3 is 21%, 29%, and 50% (p=0.486). Multivariable Cox regression analysis showed lesion length was the only significant independent predictor of ISR (hazard ratio: 1.19, p=0.039). CONCLUSION: ISR of VA origin stenting is common. Lesion length is an important predictor of ISR in VA origin stenting.     

生物可降解材料聚乳酸/聚羟基乙酸复合壳聚糖在人工冠状动脉血管支架制备中的应用

第一代金属裸支架和第二代涂层支架介入治疗冠状动脉粥样硬化性心脏病(冠心病)已得到广泛应用。由于长期存在金属支架异物刺激及其携带的药物扰乱血管壁各层细胞生长,引起支架内再狭窄和血管栓塞,远期仍有较多的主要心血管不良事件发生和需要再血管化治疗。因此,由聚酯、聚碳酸酐及聚磷酸酯等高分子材料制备的完全可生物降解吸收支架及药物洗脱支架应运而生,其中聚乳酸(poly-lactic acid,PLA)、聚羟基乙酸(poly-glycolicacid,PGA)、壳聚糖、聚己内酯(poly-caprolactone,PCL)及一些共聚物如聚乳酸/聚羟基乙酸共聚物(poly-lactic-co-glycolic acid,PLGA)材料制备的心血管植入支架的安全性、组织及血液相容性已得到证实,然而这些支架具有各自的缺点,如PLA降解较慢质硬易断裂柔韧性不足,PGA降解较快质软支撑力不足,支架降解太快或者太慢,均难以达到有效支撑,支架植入后容易出现血管损伤、弹性回缩,导致血管再狭窄及血栓形成,远期效果不佳。通过优化组合不同摩尔比的PLA和PGA及壳聚糖涂层,可以获得具有更好的生物相容性、适度的降解速率(约3～6个月完全降解)、足够的机械强度、较低的炎症反应和伸展度良好的复合材料,从而为制备完全生物可降解冠状动脉支架奠定实验基础。     

Drug eluting stents - a nightmare?

As a contribution to the controversial discussion for the use of drug-eluting stents, the European Heart Institute of the European Academy of Sciences and Arts is emphasizing important factors: a) drug eluting stents (DES) should be used only in accordance with their on-label indications for use; b) to avoid off-label use of DES and to assure that patients are apprized of all their revascularization options, patients should have informed consent between the patient, interventionist and a cardiac surgeon; c) without informed consent, off-label use of DES may be considered a legal offence against the interventionist; d) at onset of new symptoms, patients must be informed that surgery is a viable and recommended option.     

New tubular bioabsorbable knitted airway stent: biocompatibility and mechanical strength.

OBJECTIVE: This study examines the biocompatibility and suitability of a new tubular bioabsorbable knitted stent made of poly-L -lactic acid in normal rabbit airways and examines the mechanical strength of this stent in vitro. METHODS: A tubular knitted airway stent (group B, n = 15) made of poly-L -lactic acid wire was implanted operatively in New Zealand White rabbits intratracheally; silicone stents served as controls (group A, n = 8). The cervical trachea was exposed, and the stent was implanted. Up to 40 weeks after stent implantation, the rabbits were killed, at which time bronchoscopy, histologic examination, and scanning electron microscopic study was done. We tested poly-L -lactic acid stents and silicone stents for their mechanical strength in vitro. We subjected stents to area loads and measured their mechanical strengths. RESULTS: In group A, which received silicone stents, 3 (37.5%) rabbits died within 4 weeks of stent implantation as a result of airway obstruction by secretions inside the stent lumen. In group B, poly-L -lactic acid stents, 1 (6.7%) rabbit died 3 weeks after implantation because of weakness caused by anorexia. In the remaining animals, except for 1 animal with stent trouble, the bronchial lumen was fully open until the 40th week after implantation. After 40 weeks of follow-up, the stents disappeared, except for nonabsorbable suture in the bronchial wall. None of the animals in group B died of airway complication. Histologic examination and scanning electron microscopic examination of the group A silicone stents showed marked regression of ciliated cells under the stent. In group B the ciliated epithelium was preserved, and there were numerous capillary blood vessels in the submucosa. In scanning electron microscopy of the group B poly-L -lactic acid stents, the ciliated cells were preserved between the mesh holes of the stent. For diameters between 4 and 6 mm, the mechanical strength of silicone stents was greater than that of poly-L -lactic acid stents. However, the mechanical strength of poly-L -lactic acid stents increased as a function of their diameter. CONCLUSION: A new tubular bioabsorbable stent made of poly-L -lactic acid is biocompatible in normal rabbit airways, indicating that poly-L -lactic acid is a promising material for airway stents for clinical use.