不同清洗剂和清洗工艺对主动脉覆膜支架微粒的影响

对用于微创伤介入术的主动脉覆膜支架,生产过程中的清洁对其满足相关技术要求有着重要意义。主动脉覆膜支架由覆膜材料、金属材料和缝合线构成。缝合覆膜支架的过程中,缝合线通过与覆膜材料以及金属支架摩擦掉下微粒,则覆膜支架的清洗以及清洗过程中微粒的控制显得尤为重要。覆膜支架的清洗需要选择针对性的清洁剂。由于注射用水对脏污没有去污能力,所以清洗覆膜支架的首道清洗剂选用碱性或者酸性的清洗剂去除覆膜支架表面的脏污;末道清洗剂用注射用水,以便溶解上一步的清洗剂,使覆膜支架化学生物性能合格。清洗过程中去除微粒的效果主要与清洗时间、清洗剂容量和单次清洗数量等工艺控制有关。清洗时间主要根据覆膜支架的组成材料和微粒清洗要求确定;清洗剂容量则至少需满足浸没单次清洗覆膜支架数量;单次清洗数量由技术要求和生产效率等因素确定。     

Stent-grafting for unfavorable abdominal aortic aneurysm: a practical challenge

Background The endovascular treatment of abdominal aortic aneurysm （AAA） has improved greatly in the last 15 years. The present study aimed to evaluate the endografting experience for the treatment of unfavorable abdominal aortic aneurysm （uAAA）.
Methods During December 2001 and December 2007, 41 patients with uAAA were treated with endografting using concomitant techniques. Patients were followed up for 1 to 48 months （mean 20.5 months）.
Results Technical success rate was 97.6% （40/41） with 1 failure converted to open surgery for an unaccessed iliac stenosis. Nine （22.5%） type Ⅰ endoleaks （5 proximal and 4 distal） were observed on the completion angiograms and successfully corrected with aortic cuffs and iliac extensions during the procedure. Twenty-two of the planed adjunctive procedures were concomitantly performed just before endograft-implantation. There were 2 （5.0%） type Ⅰ endoleaks at 30 days; one type Ⅰ patient was treated by open conversion, another type Ⅰ patient died from a rupture before treatment in the ward, causing a 2.5% of initial mortality. The two type Ⅱ endoleaks were observed without aneurismal expansion. No buttock or leg claudication or ischemic colitis occured. During late follow-up, one additional death occurred from stroke. One new type Ⅰ endoleak was encountered from thrombocytopenia, which caused a 2.6% secondary endoleak that converted to an open surgery in the third month after a failed transabdominal banding of the aortic neck in the second month. All type Ⅱ endoleaks had disappeared in the third and sixth month. The Endografts did not present signs of material fatigue and no other type of endoleak formed. One patient presented with left limb ischemia, which underwent percutaneous transluminat angioplasty. There was no additional aneurysm rupture or any endograft imgration. Conclusion The endografting with concomitant procedures is a feasible and efficient alternative for managing unfavorable AAAs, achieving low morbidity and mortality rates and has a good clinical outcome.     

Tube Stent-Grafts for Infrarenal Aortic Aneurysm: A Matched-Paired Analysis Based on EUROSTAR Data

Objective Tube stent-grafts for treatment of infrarenal aortic aneurysms (AAAs) are a nearly forgotten concept. For focal aortic pathologies tube stent-grafts may be a treatment option. We have performed a retrospective matched-paired analysis of the EUROSTAR registry regarding the outcome of tube vs. bifurcated stent-grafts for AAA. Tapered aortomonoiliac stent-grafts were not the objective of this study. Materials and methods From July 1997 to June 2006, 7581 patients who underwent an endovascular AAA repair were entered in the EUROSTAR registry by 164 centers. One hundred fifty-three patients were treated with tube stent-grafts. For each of these 153 patients we selected one patient from a bifurcated stent-graft group (BGG-original, 7428 patients) matched according to gender, ASA, age, AAA diameter, and type of anesthesia. Differences in preoperative details between the two study groups were analyzed using chi-square test for discrete variables and Wilcoxon rank-sum test for continuous variables. Multivariate logistic regression analysis was performed on early complications. Midterm outcomes (>30 days) were analyzed by Kaplan-Meier and multivariate Cox proportional hazard model. Results The duration of the procedure was shorter in the tube stent-graft group (TGG; 102.3 ± 52.2) than in BGG (128.3 ± 55.0; p = 0.0002). Type II endoleak was less frequent in TGG (4.0%; mean follow-up, 23.12 ± 23.9 months) than in BGG (14.3%; mean follow-up, 20.77 ± 20.0 months; p = 0.0394). Type I endoleaks and migration were distributed equally, without significant differences between the groups. Combined 30-day and late mortality was higher for TGG (p = 0.0346) and was obviously not aneurysm related. Conclusions We conclude that after selection of patients, tube stent-grafts for infrarenal aortic repair can be performed with great safety regarding endoleaks and migration. The combined higher 30-day mortality and non-aneurysm-related mortality during follow-up were mainly caused by cardiac failures in our sample. On Behalf of the EUROSTAR Collaborators     

Real-time vascular interventional magnetic resonance imaging

Endovascular stent-graft placement is emerging as a promising alternative to medical and surgical treatment of patients with diseases of the descending thoracic and abdominal aorta. Precise placement of the stentgraft, which is currently performed under x-ray control, remains, however, challenging as there are several shortcomings to fluoroscopic guidance beyond that related to the harmful effect of radiation exposure and nephrotoxic contrast media. While transesophageal echocardiography and intravascular ultrasound have been used as adjunct imaging modalities during endovascular stent-graft procedures to overcome the limitations of angiography, these techniques have not mitigated the need for fluoroscopy.Magnetic resonance imaging (MRI) guidance of vascular interventional procedures offers several potential advantages over fluoroscopy-guided techniques, including image acquisition in any desired orientation, superior 3D soft-tissue contrast with simultaneous visualization of the interventional device, absence of ionizing radiation, and avoidance of nephrotoxic contrast media. Magnetic resonance imaging is often used for pre-operative diagnosis of aortic disease and can provide all relevant information for the planning of endovascular stent-graft procedures as well as for accurate and immediate post-interventional evaluation. However, visualization of interventional instruments by MRI has proven to be the chief obstacle. This article will review current approaches that have been developed for depicting vascular instruments by MRI and will also discuss the first experimental experiences with MRI-guided endovascular stent-graft placement in a swine model of aortic dissection.     

近肾动脉腹主动脉瘤开窗及分支支架腔内修复术

目的：初步探讨开窗及分支支架腔内修复术,治疗近肾动脉性腹主动脉瘤的临床应用价值.方法：回顾性分析我院大血管疾病诊治研究中心自2011年11月至2012年6月间,完成的处于开放手术修复高度危险的3例腹主动脉瘤开窗及分支支架腔内修复术,所有患者均根据术前CT血管成像三维重建结果定制开窗支架.且手术成功的2例患者于出院前及术后1个月进行了CT血管成像和/或超声复查.结果：3例患者中1例围手术期死亡,死亡原因为支架节点内漏（Ⅲ型内漏）导致瘤腔内压力快速增高,瘤体破裂死亡,2例成功.2例成功病例手术平均时间191min（185 ～ 297min）,平均使用对比剂量165mL（150～ 200mL）,平均射线剂量为367（mGy· cm）,平均失血量不足200mL.成功的2例患者术后7d BUN、血肌酐分别为21 μmol/L、17 μmol/L和64μ mol/L及67 μmol/L,1例患者出现一过性肾功能损伤,血肌酐达183 μmol/L,经内科治疗恢复至正常值以下.成功的2例患者复查CT血管成像,均显示腹腔分支血管通畅、无内漏及支架移位,腹主动脉瘤隔绝确切,下肢血流通畅.结论：开窗及分支支架旨在拓展腹主动脉瘤腔内修复术微创腔内治疗的范围.国内临床应用经验较少,有待共同总结交流.     

尼卡地平与硝普钠用于主动脉腔内修复术控制性降压效果的比较

目的:观察尼卡地平用于覆膜支架主动脉腔内修复术中控制性降压的效果,并与传统降压药物硝普钠进行比较。方法:选用40例Standford B型主动脉夹层拟经股动脉行覆膜支架主动脉腔内修复手术患者,随机分为尼卡地平(N)组和硝普钠(S)组。观察2组降压前、降压4 min和停止降压后10 min、20 min的心率(HR)、收缩压(SBP)、舒张压(DBP)、中心静脉压(CVP)和收缩压与心率乘积(RPP)的变化。结果:应用两种方法均呈现较明显的降压效果。与降压前比较,SBP、DBP明显下降(P<0.01),N组HR无显著变化,S组HR明显增快(P<0.05)。停止用药后,N组血压变化平稳,缓慢回升;S组有血压反跳现象(P<0.05)。降压4 min时,N组RPP明显下降(P<0.05),S组RPP无显著变化。CVP无显著变化。结论:尼卡地平用于夹层动脉瘤覆膜支架主动脉腔内修复术中的控制性降压作用迅速,用药后对心率无显著影响,其效果优于硝普钠,特别适用于伴有冠心病行主动脉夹层腔内修复术的患者。     

国产覆膜支架腔内隔绝术治疗Debakey Ⅲ型主动脉夹层20例

目的探讨国产覆膜支架行腔内隔绝术治疗DebakeyⅢ型主动脉夹层瘤的手术适应症、临床疗效及并发症防治。方法 2009年1月—2012年1月,采用国产覆膜支架行腔内隔绝术治疗DebakeyⅢ型主动脉夹层20例。移植物经股动脉切口导入,至胸主动脉封闭夹层裂口,手术在全麻、数字减影血管造影(DSA)监视下完成。结果 20例患者支架置入定位准确,术后即刻造影显示真腔血流恢复正常。手术成功率100%,无术中转开胸手术,无截瘫及瘤体破裂等严重并发症,无围术期死亡。结论使用国产覆膜支架行腔内隔绝术治疗DebakeyⅢ型主动脉夹层具有创伤小,术后恢复快,手术死亡率低,手术成功率高的优点,但远期效果有待进一步观察。     

Vertical Root Fracture in Buccal Roots of Bifurcated Maxillary Premolars from Condensation of Gutta-percha

Introduction

Maxillary premolars are among the teeth most susceptible to vertical root fracture (VRF) from lateral condensation of gutta-percha. These teeth are distinguished by a complex anatomy of the buccal root including a large depression in the dentin wall facing the bifurcation. It is hypothesized that tooth sectioning coupled with 2-dimensional fracture analysis is instrumental in understanding VRF in such teeth. VRF was examined by tooth sectioning following the development of a fracture mechanics analysis to predict VRF in such roots.

Percutaneous coronary intervention following repair of type B aortic dissection:a report of 8 cases

Objective Patients with aortic dissection have a significant incidence of coronary artery disease.The purpose of this study is to evaluate the safety and feasibility of percutaneous coronary stent in patients who have undergone endovascular stent,and to assess the effect of anti-coagulant and anti-platelet treatment on patients' thrombosis process.Methods From January 2005 to July 2007,8 patients who had undergone endovascular stent-graft during the past 1 to 7 months for type B aortic dissection repair,underwent percutaneous coronary intervention (PCI) because of coexisting coronary artery disease.Anti-coagulant and anti-platelet treatments were administrated after PCI according to the standard protocol.Patients were followed up for a mean period of 23 months.Clinical and false lumen status data were collected during the follow-up.Results PCI were technically successful in all 8 patients and no severe complications such as death,paraplegia,renal failure occurred during hospitalization.Complete false lumen thrombosis was observed in 5 patients and incomplete false lumen thrombosis in the remained 3 patients at the end of follow up.There were no major complications such as death,dissection rupture or aneurysm development occurred during the follow-up period.Conclusion Our data implied that PCI can be safely performed in patients with type B aortic dissection who have undergone endovascular stent-graft,without interrupting the thrombosis process.     

A computational study on the biomechanical factors related to stent-graft models in the thoracic aorta

Endovascular aortic stent-graft is a new, minimally invasive procedure for treating thoracic aortic diseases, and has quickly evolved to be one of the standard treatments subject to anatomic constraints. This procedure involves the placement of a self-expanding stent-graft system in a high-flow thoracic aorta. Stent-graft deployment in the thoracic aorta, especially close to the aortic arch, normally experiences a significant drag force which might lead to the risk of stent-graft failure. A comprehensive investigation on the biomechanical factors affecting the drag force on a stent-graft in the thoracic aorta is thus in order, and the goal is to perform an in-depth study on the contributing biomechanical factors. Three factors affecting the deployed stent-graft are considered, namely, the internal diameter of the vessel, the starting position of the graft and the diameter of curvature of the aortic arch. Computational fluid dynamic techniques are applied to model the blood flow. The inlet velocity and outlet pressure are assumed to be pulsatile. The three-dimensional continuity equation and the time-dependent Navier–Stokes equations for an incompressible fluid were solved numerically. The drag force due to the change of momentum within the stent-graft and the shear stress were calculated and analyzed. The drag force on a stent-graft will depend critically on the internal diameter and the starting position of stent-graft deployment. Larger internal diameter leads to larger drag force and the stent-graft deployed at the more distal position may be associated with significantly diminished drag force. Smaller diameter of curvature of the aortic arch probably results in a decline of the drag force on the stent-graft, even though this factor merely causes only a modest difference. These findings may have important implications for the choice and design of stent-grafts in the future. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.