经食管超声心动图在胸主动脉瘤介入治疗中的应用

血管内修复术创伤性小，可应用于治疗多种主动脉疾病，如动脉瘤和主动脉夹层。经食管超声心动图(TEE)对主动脉疾病很敏感。术前可通过TEE找到撕裂的内膜片、发现内膜破口、区分类型、区分真假腔及了解心脏状况。术中TEE用于引导导管插至正确位置、观察支架放置过程、监测心功能和室壁运动状况、评价手术疗效。术后随诊通过TEE观察支架内血流情况、检出并发症如内漏等。     

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。     

Numerical modeling and simulations of type B aortic dissection treated by stent-grafts with different oversizing ratios

Retrograde type A dissection after thoracic endovascular aortic repair has been a major drawback of endovascular treatment. This study investigated the biomechanical mechanism of stent-graft-induced new lesions after implantation and analyzed the relationship between radial force and spring-back force of the stent-graft when it was implanted virtually under different oversizing ratios. Based on the computed tomography angiography images, a three-dimensional geometric model of a patient-specific aortic dissection was established. The stent was designed in CAD software and the stent-graft implantation procedure under different oversizing ratios was simulated in the finite element analysis software. Implantation simulations were performed six times for each stent-graft model under 0%, 3%, 6%, 9%, 12%, and 15% oversizing ratios and the peak stress of the aorta was compared among groups. It was observed that the peak stress of the aorta was located where the proximal bare stent interacted with aortic wall and its value was increased by 62.2% from 0% to 15% oversizing ratio. The conclusions are reached that the long-term higher stress in the aortic wall may lead to the emergence of new lesions in these areas, and the radial force plays a key role in the formation of a new entry in the real aorta model.     

一种新型国产化人工血管内支架的研制

目的　用膨体聚四氟乙烯膜(ePTFE)膜压的方法研制一种新型的国产化人工血管内支架。方法　用0 .4mm镍钛合金丝单丝编织成自膨式血管内支架,用ePTFE拉伸成0 .0 3mm厚度的人工血管膜,分别检测其理化性能和生物学性能,最后采用膜压的方法来制作人工血管内支架。结果　研制的ePTFE人工血管各项物理性能指标相当突出,镍钛合金自膨式支架的理化性能指标均达到或超过有关标准,它们的生物学性能也完全达标,两者经过膜压成功制作出人工血管内支架。结论　国内首次采用镍钛合金支架与ePTFE人工血管膜用膜压法制成新型的国产化人工血管内支架,该支架具有良好的物理性能和生物学性能。     

Ⅱb型肾下型腹主动脉瘤20例腔内隔绝术治疗体会

目的：总结Ⅱb型肾下型腹主动脉瘤的腔内隔绝术治疗经验。方法2007年5月至2012年12月暨南大学第二临床医学院心血管外科应用分支型覆膜支架实施腔内隔绝术治疗20例Ⅱb型肾下型腹主动脉瘤患者。采用增强CT血管成像进行随访。结果8例患者成功植入Powerlink分支型支架8枚;12例患者成功植入Zenith分支型支架12枚,支架植入成功率为100%。随访10～65个月,所有支架形态正常,没有位移发生。术后1个月复查发现Ⅱ型内漏3例,6个月时复查内漏消失。术后无其他手术相关并发症发生。结论应用分支型支架腔内隔绝能安全有效地治疗Ⅱb型肾下型腹主动脉瘤。     

Thoracic endovascular aortic repair (TEVAR) in proximal (type A) aortic dissection: Ready for a broader application?

Objective

Thoracic endovascular aortic repair (TEVAR) has demonstrated encouraging results and is gaining increasing acceptance as a treatment option for aortic aneurysms and dissections. Yet, its role in managing proximal aortic pathologies is unknown—this is important because in proximal (Stanford type A) aortic dissections, 10% to 30% are not accepted for surgery and 30% to 50% are technically amenable for TEVAR. We describe our case series of type A aortic dissections treated by using TEVAR.

联合股-股动脉旁路移植术的单臂支架腔内修复腹主动脉瘤的经验

目的探讨联合股-股动脉旁路移植术(cross-femoral bypass grafting,CFBG)的单臂支架型血管(aortouniiliac,AUI)腔内修复腹主动脉瘤(endovascular aneurysm repair,EVAR)的疗效。方法1997年5月~2007年2月,对8例因髂动脉的特殊解剖条件无法应用分叉支架型血管的腹主动脉瘤采用联合CFBG的AUI支架型血管进行EVAR治疗。术后观察内漏、缺血并发症、股股旁路血管的通畅性以及下肢血供情况等。结果围手术期无死亡,1例因急性心肌梗死于术后15个月死亡。3例原发性内漏分别于术后1、3、6个月自愈。8例平均随访24个月(3~72个月),旁路均通畅,1例于术后1年吻合口轻微狭窄但无下肢缺血症状。结论因髂动脉解剖条件复杂不能应用分叉支架型血管的腹主动脉瘤采用联合CFBG的AUI支架型血管进行EVAR是安全、有效的。     

A Flexible Stent with Small Intestinal Submucosa Covering for Direct Intrahepatic Portocaval Shunt: Experimental Pilot Study in Swine

The suitability of the flexible sandwich Zilver stent-graft (SZSG) with a biologically active tissue layer (small intestinal submucosa) for creation of the intravascular ultrasound (IVUS)-guided direct intrahepatic portocaval shunt (DIPS) was explored in six young swine in a search for a flexible system to replace the rigid polytetrafluoroethylene (PTFE) stent originally used by this group with limited success. The portal vein was punctured from the inferior vena cava through the caudate lobe of the liver using IVUS guidance. After balloon dilation of the puncture tract, DIPS was successfully created in all animals with use of an SZSG 9 mm in diameter and 6 cm or 8 cm long. Only one DIPS remained well patent at 14 days when the animal had to be killed because of encephalopathy. DIPS in the other five animals were found to be either severely stenosed (3 animals) or occluded (2 animals) at 4 weeks due to accelerated formation of neointimal hyperplasia (NIH) in the liver parenchymal portion of the shunt and superimposed thrombosis. The lack of high pressure in the portal system contributed to early endograft closure. The flexible stent and the covering fail badly. The reason for this could be due to either component. More work is required to find a reliable flexible system with long-term patency. Exploration of the IVUS-guided direct extrahepatic portocaval shunt is suggested.     

Progress of the treatment for extended aortic aneurysms; is the frozen elephant trunk technique the next standard in the treatment of complex aortic disease including the arch?

Patients with extensive aortic aneurysms involving the ascending aorta, aortic arch, and the descending aorta are still considered to be a challenge for many cardiovascular surgeons. The introduction of the elephant trunk technique by Borst et al. in 1983 has greatly facilitated surgery on this kind of pathology and this technique has been recognized as a standard modality for treatment of extended aortic aneurysms. As a next step, the frozen elephant trunk technique has been introduced in some institutes in the late 1990s. With this technique, surgery is performed through a median sternotomy, and an endovascular stent-graft is placed into the descending aorta in an antegrade fashion through the opened aortic arch. Then the ascending aorta and the aortic arch are replaced conventionally. The frozen elephant trunk technique enables one-stage repair of extended aortic aneurysms in a certain patient cohort with similar operative mortality as with the conventional elephant trunk technique, in which a second-stage operation is a prerequisite. Although the surgical strategy should be adjusted specifically to each patient's individual pathology, the frozen elephant trunk technique may become the next standard treatment for extended aortic aneurysm instead of its conventional variant.     

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。