Use of arterial grafts for coronary revascularization

Objectives: The aim of this study was to evaluate the performance and the quality of arterial grafts for coronary artery bypass grafting at The Heart Institute of Japan, Tokyo Women’s Medical University.Patients and Methods: From January 1970 to March 1998, 2987 arterial grafts, including left and right internal thoracic arteries, gastroepiploic artery, radial artery and inferior epigastric artery, were used in 1673 patients. In the same period, 1225 saphenous vein grafts were used. Early graft patency was angiographically determined. Also, histological evaluation of operative specimens and preoperative angiographic evaluation of arterial grafts were performed.Results: The total number of hospital deaths was 38 (2.3%). Of 4212 grafts, 3919 grafts (93%) were evaluated angiographically and 3714 of 3919 grafts were patent (94.8%). The patency rate of internal thoracic artery was better than that of gastroepiploic artery (p < 0.0001), radial artery (p = 0.0005) and saphenous vein grafts (p < 0.0001). However, the patency rate of gastroepiploic artery was better than that of saphenous vein grafts (p = 0.04), while no significant difference was detected between gastroepiploic artery and rdial artery. Only one internal thoracic artery specimen obtained at surgery showed atherosclerotic change, but all gastroepiploic artery specimens had moderate to severe atherosclerotic changes with CD68-positive cell infiltration. Only one patient’s left internal thoracic artery out of 200 was not angiographically useable as a conduit, while multiple stenotic lesions in gastroepiploic artery were observed.Conclusions: In the graft selection for CABG, the primary choice is internal thoracic artery and the secondary choice is right internal thoracic artery, from the standpoint of histological and angiographic evaluation, gastroepiploic artery and/or radial artery, depending on the target anastomotic site, degree of stenosis, and in situ or free use is the third choice.     

Sequential and simultaneous revascularization in adult orthotopic piggyback liver transplantation.

The aim of the study was to assess whether there is a difference in outcome after sequential or simultaneous revascularization during orthotopic liver transplantation (OLT) in terms of patient and graft survival, mortality, morbidity, and liver function. The study population consisted of 102 adult patients with primary full-size piggyback OLT transplanted between January 1998 and December 2001. In 71 patients (70%) the grafts were sequentially reperfused after completion of the portal vein anastomosis and subsequent arterial reconstruction was performed (sequential reperfusion [SeqR] group). In 31 patients (30%) the graft was reperfused simultaneously via the portal vein and hepatic artery (simultaneous reperfusion [SimR] group). Patient and graft survival at 1, 3, and 6 months and at 1 year did not differ between the SeqR group and the SimR group. The red blood cell (RBC) requirements were significantly higher in the SimR group (5.5 units; range 0-20) in comparison to the SeqR group (2 units; range 0-19) (P = 0.02). Apart from a higher number of biliary anastomotic complications and abdominal bleeding complications in the SimR group in comparison to the SeqR group (13% vs. 2% and 19% vs. 6%, respectively; P = 0.06), morbidity was not different between the groups. No differences between the groups were observed regarding the incidence of primary nonfunction (PNF), intensive care unit stay, and acute rejection. This was also true for the severity of rejections. Postoperative recuperation of liver function was not different between the groups. In conclusion, no advantage of either of the 2 reperfusion protocols could be observed in this analysis, especially with respect to the incidence of ischemic type biliary lesions (ITBL).     

Hemodynamic profile and tissular oxygenation in orthotopic liver transplantation: Influence of hepatic artery or portal vein revascularization of the graft.

We performed a prospective, randomized study of adult patients undergoing orthotopic liver transplantation, comparing hemodynamic and tissular oxygenation during reperfusion of the graft. In 30 patients, revascularization was started through the hepatic artery (i.e., initial arterial revascularization) and 10 minutes later the portal vein was unclamped; in 30 others, revascularization was started through the portal vein (i.e., initial portal revascularization) and 10 minutes later the hepatic artery was unclamped. The primary endpoints of the study were mean systemic arterial pressure and the gastric-end-tidal carbon dioxide partial pressure (PCO(2)) difference. The secondary endpoints were other hemodynamic and metabolic data. The pattern of the hemodynamic parameters and tissue oxygenation values during the dissection and anhepatic stages were similar in both groups At the first unclamping, initial portal revascularization produced higher values of mean pulmonary pressure (25 +/- 7 mm of Hg vs. 17 +/- 4 mm of Hg; P < 0.05) and wedge and central venous pressures. At the second unclamping, initial portal revascularization produced higher values of cardiac output and mean arterial pressure (87 +/- 15 mm of Hg vs. 79 +/- 15 mm of Hg; P < 0.05) and pulmonary blood pressure. Postreperfusion syndrome was present in 13 patients (42.5%) in the arterial group and in 11 patients (36%) in the portal group. During revascularization, the values of gastric and arterial pH decreased in both groups and recovered at the end of the procedure, but were more accentuated in the initial arterial revascularization group. In conclusion, we found that initial arterial revascularization of the graft increases pulmonary pressure less markedly, so it may be indicated for those patients with poor pulmonary and cardiac reserve. Nevertheless, for the remaining patients, initial portal revascularization offers more favorable hemodynamic and metabolic behavior, less inotropic drug use, and earlier normalization of lactate and pH values.     

Intermittent hepatic arterial or portal occlusion reduces liver tumor growth

The effect of repeated, intermittent hepatic vascular occlusion on liver tumor growth was studied in 32 rats. An adenocarcinoma was inoculated in the left liver lobe. After 8 days, the tumor size was measured and then, in three groups, the hepatic artery was occluded intermittently during 5 days for 15 min, 1 hr, or 2 hr daily, respectively. The tumor growth after 6 days in these groups was compared with that in a group where instead the portal vein was occluded intermittently during 5 days for 15 min, and with that in a group of sham-operated control rats. In the control rats, the tumor volume (mean +/- SEM) increased from 0.16 +/- 0.03 to 1.34 +/- 0.15 cm3 during the 6 days of experiment. It was found that repeated, intermittent occlusion of the hepatic artery or the portal vein, retarded the liver tumor growth to 30-60% of the growth rate in sham-operated controls (P less than or equal to 0.015). The 15-min daily hepatic artery or portal vein occlusion was found to reduce the tumor growth rate as much as daily hepatic artery occlusion for 2 hr. It is suggested that short, daily, intermittent hepatic vascular occlusions might be efficient in the palliative treatment of liver malignancy.     

Cerebral revascularization using cadaveric vein grafts

BackgroundUse of cadaveric cryopreserved saphenous vein grafts (CSVGs) has been described for peripheral vascular and coronary revascularization. The aim of this study is to recognize CSVGs as a potential alternative to autologous conduits for extracranial-intracranial (EC-IC) bypass in patients without available or suitable saphenous vein graft or radial artery. We report the short-term patency rate of CSVGs in EC-IC bypass.MethodsWe present our preliminary experience in 10 patients using CSVG for cerebral revascularization. Data regarding operative indications, patient demographics, and bypass patency were collected.ResultsThe average age was 56 years old with equal sex distribution. The indications for the procedure were giant aneurysms in 7 patients, medically refractory vertebrobasilar ischemia in 2, and a skull base tumor in 1. ABO/Rh blood group compatible CSVG was used in each case. Postoperative angiography demonstrated patency in all cases. Quantitative magnetic resonance angiography was performed in 8 patients, demonstrating a mean bypass flow of 109 mL/min ± 19 mL/min (mean ± SE).ConclusionsUse of CSVG for EC-IC bypass has not previously been reported. In our series, the short-term patency rate was 100%, better than that found in cardiac and peripheral vascular series, possibly because of the higher flow in EC-IC bypasses. Our preliminary experience suggests that CSVGs may be an option in patients without available autologous conduits, although longer follow-up is needed to assess long-term patency.     

全动脉化冠状动脉搭桥的临床应用

目的 介绍全动脉移植物行冠状动脉搭桥的早期效果和临床经验。方法 采用全动脉移植物87例冠心病患者实施冠状动脉搭桥。其中男性患者82例,女性5例;单支冠状动脉病变14例,2支病变19例,3支病变54例。62例患者术前有心肌梗死,7例合并室壁瘤,1例合并主动脉瓣关闭不全。71例患者在体外循环下行冠状动脉搭桥术,16例在非体外循环下行冠状动脉搭桥术。同时行室壁瘤切除术7例,行主动脉瓣替换1例,行冠状动脉内膜剥脱2例。应用左乳内动脉84例次,右乳内动脉46例次,胃 网膜右动脉37例次,左桡动脉51例次。单个远端吻合14例,2个19例,3个50例,4个4例。结果 围手术期死亡2例（病死率2．3％）,1例为围手术期心肌梗死低心排,1例为顽固性心律失常。3例术后发生胸骨裂开切口感染,再次清创处理后痊愈。本组患者随访1．0－30．0个月（平均13．2个月）,1例患者因突发脑血管意外在术后40d死亡,其余患者术后均恢复良好,无心绞痛症状再发。B超检查乳内动脉移植血管均通畅。结论 全动脉化冠状动脉搭桥具有良好的临床应用效果,尤其适合于年轻的冠心病患者。     

Coagulation profiles and intraoperative substitution requirements during elective piggyback liver transplantation with prophylactic antifibrinolytic therapy

During recent years, piggyback liver transplantation (pOLT) with preservation of the retrohepatic vena cava has been introduced in adults. The objective of this study was to evaluate hemostatic changes associated with this transplantation technique. Fifty-seven patients undergoing elective pOLT for endstage liver disease were studied. Most significant changes were observed after graft reperfusion, when PT showed a 49% decrease and activated partial thromboplastin time (aPTT) as well as TT a 2- to 3-fold prolongation. At the same time, factors of the extrinsic coagulation pathway (II, V, VII) revealed an overall 50% decline. Similar changes were observed for antithrombin III (ATIII) and fibrinogen plasma levels. However, only 42% of all patients required intraoperative substitution with coagulation components. There was an association between preoperative fibrinogen (<1.7 g/dl) and ATIII (<50%) plasma levels and the substitution requirement. Multiple linear regression showed a significant correlation between preoperative ATIII activity and intraoperative blood loss. Despite a marked impairment of hemostasis, pOLT can frequently be performed with minimized substitution therapy.     

Sequential versus contemporaneous portal and arterial reperfusion during liver transplantation

Although sequential portal and arterial revascularization (SPAr) is the most common method of graft reperfusion at liver transplantation (OLT), contemporaneous portal and hepatic artery revascularization (CPAr) has been used to reduce arterial ischemia to the bile ducts. The aim of this study was to prospectively compare SPAr (group 1; n = 19) versus CPAr (group 2; n = 21) among 40 consecutive OLT from heart-beating donors. There were no differences in the demographics characteristics, Model for End-stage Liver Disease scores, indication for OLT and donor parameters between the groups. OLT was performed using the piggyback technique. The biliary anastomosis was performed in all cases by a duct-to-duct technique with a T-tube in 32% versus 29% of cases without a T tube (P = .83). In the CPAr group, the liver was reperfused simultaneously via the portal vein and hepatic artery. CPAr showed a longer warm ischemia (66 ± 8 vs 37 ± 7 minutes; P < .001), while SPAr had a longer arterial ischemia 103 ± 42 vs 66 ± 8 minutes (P = .0004). Recovery of graft function was similar. There was no primary nonfunction and delayed graft function occurred among 10% versus 9%. Liver function tests were similar between the two groups up to 90 days case of follow-up- One-year graft and patient survivals were, respectively, 89% and 95% versus 94% and 100% (P = .29). At a median follow-up of 13 ± 6 versus 14 ± 7 months, biliary complications included anastomotic stenoses in 15% versus 19% (P = .78) and intrahepatic non-anastomotic biliary strictures in 26% versus none (P = .01) for SPAr and CPAr, respectively. CPAr was safe and feasible, reducing the incidence of intrahepatic biliary strictures by decreasing the duration of arterial ischemia to the intrahepatic bile ducts.     

Coronary revascularization using only arterial grafts in patients with left main coronary artery stenosis]

Although increasing use is being made of arterial grafts (internal thoracic arteries and right gastroepiploic artery) for coronary revascularization, application to left main coronary artery (LMT) patients is frequently not possible. During the period from December 1989 to July 1991, coronary revascularization was conducted on 9 LMT patients using only arterial grafts and no venous grafts. The bypass grafts were 6 left internal thoracic artery grafts, 9 right internal thoracic artery grafts and 9 right gastroepiploic artery grafts, a total of 24 grafts and an average of 2.7 bypasses per patient. There were no operated deaths, but five patients required IABP support after cardiopulmonary bypass. They had more than 90% stenotic lesions of left main coronary artery. In contrast, four patients with less than 90% stenotic lesion were uneventful. The cause of these catastrophic hemodynamics was considered reduced blood flow by graft spasm. All patients could be functionally placed in New York Heart Association Class I or II. Postoperative stress tests were made on eight patients and the results were normal in seven. Eight patients have had postoperative angiograms. Twenty-one of 22 grafts were patent. The present results demonstrate that an arterial bypass is possible even on LMT patients by IABP support.     

Polytetrafluoroethylene grafts as the first-choice arterial substitute in femoropopliteal revascularization

We studied a series of femoropopliteal bypass operations in which polytetrafluoroethylene (PTFE) grafts were used as the first choice, regardless of the availability of saphenous vein. From Jan 1, 1979 to Dec 31, 1982, 63 PTFE femoropopliteal bypass grafts were placed in 55 patients without exploration of the saphenous vein. Forty-three grafts were placed for limb salvage, and 20 grafts were placed for disabling claudication. Patients were followed up for nine to 53 months (average, 23 months). The operative mortality was 1.8%. There were no infections. The overall patency at 30 months was 76.1%. The 30 months' cumulative patency rate for patients with claudication was 89.3%, and there were no amputations. The cumulative 30-month patency for limb salvage was 70.1%, and there was a limb salvage rate of 81.2%. Because the 30-month results were comparable with reported series using autogenous saphenous vein, we concluded that PTFE conduits may be considered the first-choice arterial substitute for femoropopliteal reconstruction. Until longer follow-ups are available, reversed autogenous saphenous vein should probably be the graft of first choice in younger patients (less than 60 years of age) without coronary artery disease who are undergoing femoropopliteal revascularizations.     

Heparin utilization during arterial revascularization.

These studies demonstrate that therapeutic levels of heparin are achieved when either 100 u/kg or 150 u/kg are administered prior to arterial or aortic cross clamping during peripheral vascular reconstructive procedures. They further demonstrate that adequate levels of heparin are maintained for at least one hour even with the lower dosage. If heparin effect is not reversed, many patients will be returned to the recovery ward with therapeutic levels of heparin.This is undesirable and can be averted by administering appropriate doses of protamine sulfate. Excesses of protamine sulfate should be avoided since unbound protamine sulfate has anticoagulant as well as cardiovascular effects.     

背驮式肝移植可视化仿真手术的研究

目的 研究三维可视化仿真手术技术在背驮式肝移植中的应用价值.方法 利用2例胆总管结石患者的肝脏64排CT扫描数据,对CT图像进行分割,三维重建.重建出的肝脏及其管道模型分别以STL格式导入FreeForm Modeling System进行修饰和平滑.利用系统的力反馈设备,进行背驮式肝移植手术的仿真研究.结果 重建的肝脏模型形态逼真,立体感强;手术模拟过程真实、形象,且有"力"的感受.结论 可视化的肝脏重建模型立体、逼真,有利于肝移植手术方案的合理设计,降低手术风险及减少手术并发症;虚拟肝移植手术有利于医务人员的培训和学习.     

Role of right gastroepiploic artery in myocardial revascularization with arterial grafts

Between July 1990 and December 1992, 112 patients underwent myocardial revascularization with arterial grafts in the Department of Cardiac Surgery, University of Milan. Monovascular patients were excluded from the study. The right gastroepiploic artery was used in 44 patients (39.3%); mean age was 54.3 years and reoperation rate 18.2%. Of the 44 patients, previous myocardial infarction had occurred in 25 (57%). Emergency operation was performed in one case (2%). Mean left ventricular shortening fraction was 36% and mean ejection fraction 58.6%. Coronary artery disease was bivascular in 10 patients (23%) and trivascular in 34 (77%). The arterial revascularization in patients with gastroepiploic artery was performed using a left internal thoracic artery graft in all 44 patients; the right internal thoracic artery was used in 18 (41%) and the inferior epigastric artery in two (4%). The sites of gastroepiploic artery grafting were 55% posterior descending, 16% right coronary artery, 11% posterolateral branch, 14% circumflex and in 4% posterior descending and posterolateral as sequential graft. No patient died; postoperative myocardial infarction rate was 4%. No complications related to gastroepiploic artery utilization were noted. Forty-three (98%) of the gastroepiploic artery group underwent graft reinvestigation: the arteries were correctly visualized in 41 patients (95%) and were patent in 39 cases and stenotic in two. A mid-term postoperative stress test (mean 17.4 months) was performed in 91% of patients. Normal limits were found in 37 patients (92.5%) and an abnormal stress test result in three (7.5%). The contemporary follow-up showed no deaths or myocardial infarctions. Three patients (7%) had recurrent angina. The rote of gastroepiploic artery in arterial revascularization has become fundamental, especially, it is believed, for the posterior or posterolateral left ventricular wall. The present data show the patients to be clinically and functionally well 1 year after operation.     

背驮式肝移植术中血液动力学改变

目的观察背驮式原位肝移植术患者术中不同时期血液动力学的变化。方法患者15例,男12例,女3例,年龄8～75岁,体重22.5～75kg。均因终末期肝病在静吸复合全身麻醉下行背驮式肝移植术。术中对患者HR、ECG、PETCO2、SpO2、有创动脉压、平均肺动脉压(MPAP)、肺毛细血管楔压(PCWP)、中心静脉压(CVP)进行监测,并用热稀释法监测心排血量(CO)、心脏指数(CI)、每搏量(SV)、外周血管阻力(SVR)。对手术切皮后30min、无肝期30min及新肝期30min三个时点的血液动力学指标进行统计分析。结果各时点MAP及CVP无明显变化;无肝期HR、SVR明显高于切皮后30min和新肝期30min(P<0.05或P<0.01);无肝期MPAP、PCWP、CO、SV、CI均明显低于切皮后30min和新肝期30min(P<0.01)。结论背驮式肝移植术无肝期MAP能相对稳定,但其他血液动力学指标的变化仍较明显,应加强此术式中血液动力学的监测和管理。