CT血管造影分析体外循环与非体外循环冠状动脉旁路移植后的桥血管通畅率

背景：近年来,非体外循环冠状动脉旁路移植后桥血管通畅率是否与传统的体外循环冠状动脉旁路移植相同存在争议。 目的：探讨体外循环与非体外循环冠状动脉旁路移植后桥血管时间通畅率的差异性。 方法：选取同一操作者行体外循环冠状动脉旁路移植患者100例,按其临床特征及桥血管病变危险因素匹配抽取非体外循环冠状动脉旁路移植患者137例。采用64排多螺旋CT血管造影分析冠脉搭桥后1个月,1年,2年,3年,4年的桥血管通畅情况。 结果与结论：共对641条桥血管进行评价,两组中左侧乳内动脉桥血管时间通畅率均高于大隐静脉桥,两组左侧乳内动脉桥和大隐静脉桥血管时间通畅率比较差异均无显著性意义。说明非体外循环与体外循环冠状动脉旁路移植后患者桥血管时间通畅率相似,对于某些适当的患者来说,非体外循环冠状动脉旁路移植不失为一个良好的选择。     

自体静脉血管移植粥样硬化研究进展

冠脉搭桥是治疗冠状动脉闭塞性病变的主要方法.血管组织工程首要任务就是为其提供“桥梁材料”即冠状动脉替代物,包括人工血管、异体血管和自体血管等.临床和实验研究均显示这些替代物各有优劣势.自体静脉血管是三类“桥梁材料”应用最为广泛的材料,但移植后粥样硬化发生是目前最大的难题.本文对自体血管的研究进展给予综述,以期为深入开展...     

一种可以避免血管再狭窄的双移植管搭桥方式的数值模拟

目的为改善冠状动脉旁路移植管的局部血流动力学,降低血管再狭窄的发生机率,研究一种可以避免血管再狭窄的双移植管搭桥方式。方法利用有限元分析方法,对传统模型和双移植管搭桥模型进行血流动力学模拟仿真,计算缝合区附近的流场、壁面切应力等血流动力学因素的分布情况。结果该双移植管搭桥具有较好的血流动力学分布,明显改善了主搭桥血管与冠状动脉缝合处的血流动力学参数,消除了该部位的涡流和流动停滞点,提高了底面的壁面切应力数值。在辅助搭桥血管与冠状动脉缝合处涡流区长度仅3 mm,与原主搭桥血管缝合处的涡流长度4.5 mm相比明显减小。辅助搭桥管分流了约36%的血液,只有约64%的血液流过了主搭桥管。结论该双移植管搭桥有助于减小内膜增生的发生机率。     

左乳内动脉冠状动脉旁路移植患者原位与游离状态的流量测定

背景:左乳内动脉旁路移植以疗效可靠、远期通畅率高而成为冠心病外科治疗的首选和标准技术。但左乳内动脉是否合适行序贯吻合及序贯血管的血流量是否能满足人体需要一直存在争议。目的:探讨接受非体外循环下左乳内动脉冠状动脉旁路移植患者左乳内动脉原位与游离状态的血流量之间的差别。方法:选择2008-03/2009-03接受非体外循环下左乳内动脉冠状动脉旁路移植患者56例,术中先游离出左乳内动脉近端一小段无蒂光滑区,待循环稳定后,利用即时血流检测仪先进行左乳内动脉原位血流测定,再将左乳内动脉所有侧支完全离断,在远端离断之前,进行左乳内动脉原位游离状态的流量测定。结果与结论:56例冠心病患者左乳内动脉主干原位血流明显好于游离状态的主干原位血流[(32.0±5.0),(10.0±1.2)mL/minP0.01],表明左乳内动脉主干血流与其分支数目有关;左乳内动脉具有一定的流量储备,可为冠脉搭桥序贯吻合提供理论依据。     

4种大鼠睾丸移植模型的建立方法与比较

目的: 比较4种大鼠睾丸移植模型的建立方法。方法: 建立4种不同术式的大鼠睾丸移植模型各10例，分别比较其血管重建时间、即时通畅率、显微外科技术要求及术后1个月植睾血供情况和功能。结果: 40例受体大鼠存活均超过30 d，4种方法的血管重建时间和显微外科技术难易程度有所不同，但开放血流后即时通畅率及术后1个月植睾血供情况和血清睾酮水平相互比较无明显差异。 结论: 4种方法均可选择性地用于不同解剖类型的大鼠睾丸移植的实验研究。     

病例男性61岁:胸痛和进行性疲劳心导管检查术

左心室心导管检查术采用传统的由右股静脉进入的Judkin氏方法进行,发现冠状动脉接近冠状动脉左前降分支第3分支末端中度狭窄,冠状动脉的第1终未分支起始部高度狭窄.而右侧弯曲的右冠状动脉分支系统则相对没有狭窄.左侧胸内动脉搭桥通向左冠状动脉左前降支及通向第1终末分支的搭桥的隐静脉是开放的.然而,当向冠状动脉注入显影剂发现该显影物排泄明显延迟(冠状动脉"盗血"现象).这种现象可因冠状血流流向微血管系统障碍造成. 左室血管造影照片显示左室扩大伴弥漫性,射血分数下降.     

冠状动脉与冠脉搭桥术常用自体血管的比较研究进展

冠脉搭桥术 (coronaryarterybypassgrafting ,CABG)在发达国家已成为心外科常规手术而普遍开展 ,在我国 ,自北京阜外医院开展第一例冠脉搭桥手术至今已 2 0多年 ,该手术在全国的开展正逐步增多。冠状动脉狭窄部位好发于前室间支 ,其次为右冠状动脉和旋支 ,CABG手术的目的是为阻塞的部位建立侧支循环恢复其血供。目前临床应用的冠脉搭桥移植材料有自体血管和人造血管两种 ,人造血管因有较多的并发症 ,只是在采用病人自体血管有禁忌症时作替代使用[1] ;常用的自体血管桥有大隐静脉、胸廓内动脉、胃网膜右动脉和桡动脉 4种。现就冠状动脉与…     

自体腹膜管替代动脉实验研究的形态学观察

用犬的自体带（腹直肌后）鞘的腹膜组织片缝制成管状，作为血管的替代材料移植于腹主动脉，移植后分别于早期（２周内）、中期（８￣１０周以后）处死动物，取移植腹膜管进行大体，光镜及扫描电镜观察，结果发现，早期有附壁血栓形成，中后期则在多内壁光滑，表面覆盖内皮样细胞，管壁纤维组织增生，提示此种自体腹膜管完全可以作为一种新型的自体血管替代材料。     

病例 男性61岁:胸痛和进行性疲劳

(上接本刊第6卷第1期　Ｐ78)心导管检查术左心室心导管检查术采用传统的由右股静脉进入的Ｊｕｄｋｉｎ氏方法进行,发现冠状动脉接近冠状动脉左前降分支第3分支末端中度狭窄,冠状动脉的第1终未分支起始部高度狭窄.而右侧弯曲的右冠状动脉分支系统则相对没有狭窄.左侧胸内动脉搭桥通向左冠状动脉左前降支及通向第1终末分支的搭桥的隐静脉是开放的.然而,当向冠状动脉注入显影剂发现该显影物排泄明显延迟(冠状动脉“盗血”现象).这种现象可因冠状血流流向微血管系统障碍造成.左室血管造影照片显示左室扩大伴弥漫性,射血分数下降.表2总结了心导管…     

体外循环冠状动脉搭桥术中不同停跳液灌注方法的心肌保护作用

背景:体外循环下冠状动脉搭桥的远期效果优于常温冠状动脉搭桥。对于严重冠脉狭窄患者,单纯经主动脉根部顺行灌注心肌保护效果欠佳,如何取得良好的心肌保护效果成为影响搭桥效果的关键因素之一。目的:比较体外循环下应用不同停跳液灌注方法对冠状动脉移植搭桥患者心肌的保护作用。方法:23例冠状动脉移植搭桥患者,根据停跳液灌注方法的不同分为主动脉根部灌注组;主动脉根部灌注+冠状动脉桥灌注组;主动脉根部灌注+经冠状静脉窦逆行灌注组。分别于搭桥前、体外循环30 min、升主动脉开放后5 min、2 h、6 h、24 h取血标本测量血清肌钙蛋白Ⅰ、磷酸肌酸激酶和磷酸肌酸激酶同工酶水平,记录体外循环时间、升主动脉阻断时间、升主动脉开放后心脏复跳情况、搭桥后正性肌力药物的应用情况、气管插管拔管时间及ICU停留时间等临床监测指标。结果与结论:肌钙蛋白Ⅰ复灌后2-24 h;CK复灌后5 min到24 h;磷酸肌酸激酶同工酶复灌后6,24 h,主动脉根部灌注+冠脉桥灌注组与主动脉根部灌注+经冠状静脉窦逆行灌注组明显低于主动脉根部灌注组(P0.05)。心脏自动复跳率及多巴胺应用等临床监测指标3组比较差异无显著性意义。结果表明,应用心脏停跳液进行冠状动脉顺行性灌注的同时结合冠状动脉桥灌注或经冠状静脉窦逆行灌注,对心脏体外循环冠状动脉移植搭桥可取得良好的心肌保护效果。     

Both skeletonized and pedicled internal thoracic arteries supply adequate graft flow after coronary artery bypass grafting even during intense sympathoexcitation

The internal thoracic artery (ITA) is harvested by either the pedicled or the skeletonized technique in coronary artery bypass grafting (CABG), with no clear advantage of one technique over the other. We compared graft flow between the pedicled and skeletonized ITA grafts while varying myocardial oxygen demand. CABG was performed to the left anterior descending artery in five anesthetized dogs using a pedicled ITA graft and the graft was subsequently skeletonized. Graft flow was measured during stepwise electrical stimulation of the stellate ganglion. The baseline graft flow before sympathetic stimulation was higher in skeletonized (27.8 ± 1.9 ml/min) than that in pedicled ITA grafts (22.6 ± 2.7 ml/min) (P < 0.05). In both ITA grafts, however, graft flow increased to a similar level during sympathetic stimulation that doubled the double product, correlating with the double product. Based on these results, we conclude that metabolic demand can override the potential difference in sympathetic vasoconstriction in both pedicled and skeletonized ITA grafts.     

Hybrid small-caliber vascular prosthesis for coronary artery bypass grafting: a preliminary study of plasmin-treated fibrin-coated vascular prosthesis

The potential use of plasmin-treated fibrin-coated vascular prosthesis (PF-V) for coronary artery bypass grafting (CABG) in animal models was investigated. PF-V grafts, 3 mm in internal diameter, were studied on 5 sheep in off-pump CABG model and on 18 rabbits in abdominal aortic bypass grafting (AABG) model. Patency, blood flow, angiography, Indium-111 platelet scintigraphy, and histology of the graft were evaluated. In the sheep CABG model, the PF-V grafts were patent for a range of 12 to 22 days without postoperative antiplatelet therapy. Graft flows ranged 58 to 90 ml/min until the day before graft occlusion by thrombus. In rabbit AABG model, the fibrin coating of the PF-V grafts was completely absorbed and replaced with neofibrin net between 7 and 14 days after implantation. Platelet depositions on the graft between 7 and 14 days after implantation were significantly higher than those at other periods (p < 0.05). The small-caliber PF-V graft in sheep CABG model had a good blood flow with high antithrombogenicity in acute phase, but occluded over 2 to 3 weeks without antiplatelet agents after implantation. The current problem of the PF-V graft was a thrombus formation at the time of the degradation of fibrin coating. Further improvements are needed.     

组织型纤溶酶原激活剂在移植血管桥再狭窄动物血管的差异表达

目的研究组织型纤溶酶原激活剂（t—PA／PLAT）在移植血管桥再狭窄动物血管的差异表达。方法通过兔双侧颈动脉进行动脉桥和静脉桥的移植,形成双侧移植血管桥再狭窄动物模型。应用免疫组化检测t-PA在动物模型动脉桥、静脉桥的表达并进行比较。结果血管桥移植前,t-PA在实验动物颈动脉和颈静脉的表达差异无统计学意义（P〉0．05）;血管桥移植后,t-PA在动脉桥的表达明显高于静脉桥（P〈0．05）,于16周时达到高峰[（32．34±4．74）％比（16．74±3．14）％],以后随时间延长而出现表达减少（P〈0．05）。结论t-PA在术后早期对血管桥具有保护作用,其表达的高低与术后血管桥再狭窄关系密切。     

犬不停跳冠状动脉搭桥模型的构建

目的比较两种不同方法构建不停跳冠状动脉搭桥动物模型,探讨模型构建方法的可行性和优劣性。方法家犬20只随机分为头臂干组和降主动脉组,以小口径异种血管为桥血管。左侧第4肋间切口入胸,先行头臂干动脉或降主动脉端血管吻合,再行冠状动脉端血管吻合,术毕结扎左冠状动脉前降支近端。结果 2组犬均无术中死亡。头臂干组和降主动脉组主动脉端血管吻合用时分别为(33.9±4.8)min和(29.6±3.5)min(P0.05),冠状动脉端血管吻合用时分别为(28.5±3.0)min和(28.1±2.3)min(P0.05),2组术中出血量分别为(77.5±16.2)mL和(66.5±12.3)mL(P0.05)。降主动脉组术中侧壁钳夹降主动脉后股动脉血压明显降低,术后2只犬出现黑便。结论将小口径异种血管吻合在头臂干动脉或降主动脉均可成功构建犬不停跳冠状动脉搭桥模型;降主动脉组股动脉血压波动大,存在腹腔脏器缺血再灌注损伤;头臂干组血管吻合用时稍长,但术中股动脉血压波动小,模型构建相对更安全。     

Uterine artery as an arterial conduit for coronary artery bypass graft (CABG) surgery in women: A role for estrogen-receptor alpha (ER-α) in the prevention of post-CABG accelerated atherosclerosis and graft disease

Coronary artery bypass graft (CABG) surgery is the standard of care in the treatment of advanced coronary artery disease (CAD). In order to bypass coronary occlusions, CABG surgery traditionally employs grafts from the left internal thoracic/mammary artery (LITA/IMA), radial artery (RA), and greater saphenous vein (SV). The risk of CABG failure is reported to be higher, or at best similar, for women than for men, and it relates primarily to post-operative accelerated atherosclerosis leading to graft stenosis and recurrent angina, a phenomenon known as “coronary artery bypass graft disease”. In this paper, the authors hypothesize that employing an alternative arterial conduit may help reduce the rate of post-CABG accelerated atherosclerosis in women, and propose that a uterine artery specimen be used instead. Given its greater density of estrogen-receptor alpha (ER-α) relative to other mammalian endothelial cells in the vasculature, uterine arteries may exhibit important anti-atherosclerotic properties. Theoretically, this effect may be amplified with the adjuvant administration of low-dose selective ER-α agonist modulator (SERM) therapy.     

The impact of the preoperative severity of target-vessel stenosis on the short-term patency of radial artery grafts

The fate of a grafted radial artery remains unknown. The purpose of this study was to determine whether the preoperative severity of stenosis of the target vessel influence short-term patency of radial artery (RA) grafts used as coronary artery bypass conduits. In 54 patients who had coronary artery bypass grafting (CABG) with RA grafts, RA patency was determined with multi-slice computed tomography (MSCT) 1 year after CABG. These patients were divided into three groups on the basis of the percentage of the target vessel stenosis: mild (< 60%, n=17), moderate (60% to 79%, n=19), and severe (>/= 80%, n=18). MSCT was also performed 1 week later to exclude early occlusion of RA grafts. In 3 patients, the MSCT failed to adequately discriminate the status of the RA graft due to poor image resolution. The overall incidence of RA occlusion was 23.5% (12 of 51) at 1 year in the entire population. The mild stenosis, moderate stenosis and severe stenosis group showed an occlusion rate of 50% (8 of 16), 23.5% (4 of 17) and 0% (0 of 18), respectively. The severe stenosis group had significantly lower rate of RA graft occlusion compared to the mild stenosis group (p < 0.001) and moderate stenosis group (p < 0.05). No difference in occlusion between grafts used for the different coronary artery branches could be demonstrated. Preoperative severity of the target coronary artery significantly affected the short-term RA grafts patency. Correct indication is the key factor for short-term RA patency.     

Surgical sealant in the prevention of early vein graft injury in an ex vivo model.

BACKGROUND: The amelioration of the adaptation process (arterialisation) of the vein graft wall to the arterial circulation in coronary artery bypass surgery by using extravascular support is clearly established in animal models and in in vitro and ex vivo set-ups. This support consists of some form of external graft-supporting modality like a prosthetic graft of stent. The clinical application of perivenous support, however, is hampered due to the fact that no easy applicable external support is available. Considering that application in the form of a spray is the most convenient modality, we evaluated whether polyethylene glycol is capable of providing adequate perivenous support. Polyethylene glycol is a synthetic, biodegradable product, used in cardiac surgery as a sealant, and is commercially available in the form of a spray. METHODS: Segments of human saphenous vein graft obtained during coronary artery bypass graft (CABG) procedures were placed in an ex vivo model, a side loop of the extracorporeal perfusion circuit, and perfused with autologous blood, making the circumstances identical to the implanted saphenous vein grafts concerning pressure, temperature, level of complement and leukocyte activation and blood pressure. Alternately around every other study vein graft segment polyethylene glycol was applied. Unsupported grafts served as control. After 1 min of solidification, perfusion was started with a pressure of about 60 mmHg (nonpulsatile flow). Perfusion was maintained for 60 min, after which the grafts were collected for light microscopy and electron microscopy. RESULTS: Light microscopy and electron microscopy showed remarkable attenuation of endothelial cell loss and less injury of smooth muscle cells of the circular and longitudinal layer of the media in the supported group compared to the nonsupported vein graft segments. CONCLUSION: Polyethylene glycol is able to provide adequate external vein graft support, preventing overdistension, in an ex vivo model. This provides a basis for clinical application. Further investigation is warranted to evaluate long-term effects.     

Estimation of wall shear stress in bypass grafts with computational fluid dynamics method

Coronary artery bypass graft (CABG) operation for coronary artery disease with different types of grafts has a large clinical application world wide. Immediately after this operation patients are usually relieved of their chest pain and have improved cardiac function. However, after a while, these bypass grafts may fail due to for example, neointimal hyperplasia or thrombosis. One of the causes for this bypass graft failure is assumed to be the blood flow with low wall shear stress. The aim of this research is to estimate the wall shear stress in a graft and thus to locate areas were wall shear stress is low. This was done with the help of a blood flow computer model. Post-operative biplane angiograms of the graft were recorded, and from these the three-dimensional geometry of the graft was reconstructed and imported into the computational fluid dynamics (CFD) program FLUENT. The stationary diastolic flow through the grafts was calculated, and the wall shear stress distribution was estimated. This procedure was carried out for one native vessel and two different types of bypass grafts. One bypass graft was a saphenous vein and the other one was a varicose saphenous vein encased in a fine, flexible metal mesh. The mesh was attached to give the graft a defined diameter. The computational results show that each graft has distinct areas of low wall shear stress. The graft with the metal mesh has an area of low wall shear stress (< 1 Pa, stationary flow), which is four times smaller than the respective areas in the other graft and in the native vessel. This is thought to be caused by the smaller and more uniform diameter of the metal mesh-reinforced graft.     

Thallium scintigraphy in prediction of occlusion of bypass grafts in asymptomatic and symptomatic patients

To evaluate thallium scintigraphy in predicting coronary artery bypass graft patency, exercise thallium scintigraphy and selective graft and native vessel angiograms were performed in 22 asymptomatic and 29 symptomatic consecutive patients three months after coronary artery bypass grafting (CABG). Twelve out of 22 asymptomatic patients (55%) had reversible thallium defects on postoperative images; in 10 patients the postoperative scans were normal. The graft patency was significantly lower in asymptomatic patients with abnormal thallium perfusion compared to those with normal perfusion after CABG (68% vs. 91%, p less than 0.05). The rate of graft patency in symptomatic patients was 66/87 (76%). Thallium scintigraphy was 77% sensitive and 78% specific in detecting one or more stenosed or occluded bypass grafts in patients without angina (accuracy 77%). When data from exercise electrocardiography were combined with scintigraphy, all but one patient with incomplete revascularization could be detected (positive predictive accuracy 92%). In symptomatic patients, thallium scintigraphy accurately predicted the presence or absence of graft occlusion in 24/29 (83%) cases. Thus, abnormal myocardial perfusion due to stenosis or occlusion of bypass grafts is common in both asymptomatic and symptomatic patients after CABG. Thallium scintigraphy together with exercise electrocardiography appear to be useful non-invasive methods in detecting painless myocardial ischemia and in predicting bypass graft occlusion after CABG.     

桡动脉在全动脉化冠脉搭桥术中的临床应用

目的探讨桡动脉在全动脉化冠脉搭桥术中的临床应用效果。方法22例患者采用乳内动脉和桡动脉行全动脉化冠脉搭桥手术,"不接触血管技术"游离桡动脉,与冠状动脉对角支、钝缘支、前降支、右冠状动脉等单独或序贯吻合,共搭桥31支。术后应用钙通道阻滞剂防止桡动脉痉挛。结果22例手术均顺利完成,痊愈出院,无围术期心肌梗塞,术后心肌缺血改善,无手部缺血并发症。随访2月～3年,无心绞痛复发,手部功能正常。结论桡动脉作为血管桥材料在全动脉化冠脉搭桥术中应用效果良好。