Contemporary use of arterial and venous conduits in coronary artery bypass grafting: anatomical,functional and clinical aspects

Although the benefits of using the left internal mammary artery to bypass the left anterior descending artery (LAD) have been extensively ascertained, freedom from major cardiovascular events and survival after coronary artery bypass grafting (CABG) also correlate with the completeness of revascularisation. Hence, careful selection of the second-best graft conduit is crucial for CABG success. The more widespread use of saphenous vein grafts contrasts with the well-known long-term efficacy of multiple arterial grafting, which struggles to emerge as the procedure of choice due to concerns over increased technical difficulties and higher risk of postoperative complications. Conduit choice is at the discretion of the operator instead of being discussed by the heart team, where cardiologists are not usually engaged in such decisions due to a hypothetical lack of technical knowledge. Furthermore, according to the ESC/EACTS guidelines, traditional CABG remains the gold standard for multi-vessel coronary artery disease with complex LAD stenosis, but hybrid procedures using percutaneous coronary intervention for non-LAD targets could combine the best of two worlds. With the aim of raising the cardiologist’s awareness of the surgical treatment options, we provide a comprehensive overview of the anatomical, functional and clinical aspects guiding the decision-making process in CABG strategy.     

Robotic totally endoscopic multivessel coronary artery bypass grafting: procedure development, challenges, results

Closed-chest totally endoscopic coronary artery bypass grafting (TECAB) is feasible using robotic technology. During the early phases, TECAB was restricted to single bypass grafts to the left anterior descending artery system. Because most patients referred for coronary artery bypass surgery have multivessel disease, development of endoscopic multiple bypass grafting is mandatory. Experimental work on multivessel TECAB was carried out in the early 2000s, and first clinical cases were already performed. With further technological development of operating robots, double, triple, and quadruple TECAB has become feasible both on the arrested heart and on the beating heart. To date, 161 cases of multivessel TECAB using the da Vinci telemanipulation systems are published in the literature. The main advances enabling multivessel TECAB were the availability of a robotic endostabilizer for beating heart procedures and increased surgeon skills using remote access heart-lung machine perfusion and endo-cardioplegia. Both internal mammary arteries can be harvested and both radial artery and vein graft can be used in multivessel TECAB. Y-grafting and sequential grafting are feasible. Multivessel endoscopic surgical revascularization can be combined with percutaneous coronary interventions in advanced hybrid coronary revascularization. Time requirements for multivessel TECAB are significant, and conversion rates to larger thoracic incisions are higher than those observed for single-vessel TECAB. Clinical short- and long-term outcomes, however, seem to meet the standards of open coronary bypass surgery through sternotomy. The main advantages of multivessel TECAB are a completely preserved sternum, use of double internal mammary artery even in risk groups, and a remarkably short recovery time.     

Capacities of multidetector spiral computed tomography in the planning and postoperative examination of patients undergoing coronary artery bypass surgery

Multiple investigations show that multidetector spiral computed tomography (MSCT) bypass grafting becomes an alternative to invasive coronary angiography in detecting coronary graft stenoses and occlusions. The investigation retrospectively estimated the patency of aortocoronary and mammary coronary artery anastomoses by MSCT bypass grafting. Examinations were made in 85 (326 anastomoses) patients who had undergone aortocoronary and mammary coronary artery bypass surgery and had MSCT bypass grafting within 3 years after the surgery. In the first year following the surgery, 18 patients with graft stenotic changes, as evidenced by MSCT, underwent intervention coronary angiography, the sensitivity and specificity of which was 100%. The results of clinical and instrumental examinations were also compared with graft incompetence, as shown on MSCT that revealed that MSCT bypass grafting was the only noninvasive technique to evaluate early coronary graft closure both in the absence of clear signs of myocardial ischemia according to the data of exercise tests and in the presence of recurrent angina pectoris.     

Concomitant transapical transcatheter aortic valve implantation and minimally invasive direct coronary artery bypass

We represent a successful minimally invasive combined off-pump procedure consisting of a transapical aortic valve implantation and a direct coronary artery bypass grafting in a woman with a severe aortic stenosis and a critical coronary artery disease. Due to her comorbidities, she was classified as a high-risk patient qualifying for a transcatheter procedure. We performed this combined procedure in a hybrid operation room, starting with the coronary bypass to maintain a coronary blood flow during the transapical valve implantation. The operation processed without any complications and she was discharged at the seventh postoperative day into the allocating hospital.     

Selection and care of cardiac patients for plastic surgery

A major operation after successful coronary artery bypass surgery has been proved as safe as an operation for a patient free from coronary artery disease. Most patients with angina who demonstrate an operable coronary lesion should usually be scheduled for coronary artery bypass before undergoing nonemergency surgery. It is advisable to postpone elective plastic surgery for 6 weeks to 3 months after coronary bypass and 6 months after myocardial infarction. The life expectancy of cardiac patients must be carefully considered before elective plastic surgery, because performing an operation on a patient who cannot live to enjoy the benefits is unwise. Working together, cardiac surgeons, cardiologists, and plastic surgeons can now prolong the quantity of life and enrich its quality in properly selected and carefully managed patients.     

Simultaneous off-pump coronary artery bypass grafting and ascending aortobifemoral bypass graft via ventral abdominal route

Aortoiliac disease often coexists with coronary artery disease. It is not uncommon to subject a patient to two separate interventions. We report two cases in which in simultaneous off-pump coronary artery bypass grafting was done with an ascending aortobifemoral bypass graft through the ventral abdominal route without any additional morbidity. Combining a technically simple method of limb bypass with an off-pump cardiac surgery is a promising procedure for revascularization of myocardium and lower limbs. We discuss the merits of combining an off-pump coronary artery bypass grafting procedure with a limb bypass.     

Early antiplatelet therapy in coronary artery bypass grafting: a calculated benefit

Studies have demonstrated that antagonists of platelet activity, including aspirin and clopidogrel, reduce the risk of major adverse events in patients with acute coronary syndromes. Although antiplatelet agents also convey an increased risk of bleeding, particularly in patients proceeding to coronary artery bypass graft surgery, in most cases, the benefits of early initiation of antiplatelet therapy outweigh the risks. The purpose of this review is to distinguish perceived and actual risk versus the benefit associated with early antiplatelet therapy to help clinicians make informed decisions on using these agents in an acute setting where patients may require coronary artery bypass grafting.     

Robotically assisted coronary endarterectomy

Robotic assistance has enabled coronary artery bypass surgery to be performed safely in a completely endoscopic fashion, but diffusely diseased target vessels may pose a technical challenge. We present a case in which coronary endarterectomy was performed on the left anterior descending coronary artery during a two-vessel totally endoscopic coronary artery bypass procedure. A 52-year-old woman presented with intermittent substernal pain. Preoperative studies showed diffuse disease in the left coronary artery system. Bilateral internal mammary arteries were harvested robotically using a skeletonized technique in a completely endoscopic fashion. Cardiopulmonary bypass was achieved via peripheral cannulation, and the heart was arrested with intermittent cold antegrade hyperkalemic blood cardioplegia delivered via an ascending aortic occlusion balloon catheter. The first obtuse marginal anastomosis was performed. The left anterior descending coronary artery was diffusely diseased and heavily calcified. An end-to-side anastomosis was attempted to the right internal mammary artery with unsatisfactory results. A localized coronary endarterectomy was performed, and an extended anastomosis was completed using the right internal mammary artery. The patient recovered uneventfully and was discharged home on postoperative day 6. Diffuse coronary artery disease was once thought to be a prohibitive challenge for minimally invasive coronary bypass procedures. This case demonstrates that local coronary endarterectomy is feasible and safe in robotic totally endoscopic coronary artery bypass surgery.     

Evaluation of a Novel Laser-assisted Coronary Anastomotic Connector - the Trinity Clip - in a Porcine Off-pump Bypass Model

To simplify and facilitate beating heart (i.e., off-pump), minimally invasive coronary artery bypass surgery, a new coronary anastomotic connector, the Trinity Clip, is developed based on the excimer laser-assisted nonocclusive anastomosis technique. The Trinity Clip connector enables simplified, sutureless, and nonocclusive connection of the graft to the coronary artery, and an excimer laser catheter laser-punches the opening of the anastomosis. Consequently, owing to the complete nonocclusive anastomosis construction, coronary conditioning (i.e., occluding or shunting) is not necessary, in contrast to the conventional anastomotic technique, hence simplifying the off-pump bypass procedure. Prior to clinical application in coronary artery bypass grafting, the safety and quality of this novel connector will be evaluated in a long-term experimental porcine off-pump coronary artery bypass (OPCAB) study. In this paper, we describe how to evaluate the coronary anastomosis in the porcine OPCAB model using various techniques to assess its quality. Representative results are summarized and visually demonstrated.     

NONCARDIAC SURGERY COMBINED WITH CORONARY ARTERY BYPASS

The coexistence of coronary artery disease with noncardiac disease often leads to a dilemma in planning therapeutic procedures. This problem is especially difficult in the presence of accelerated angina or left coronary artery stenosis. A series of 17 patients is presented in which coronary artery bypass grafts were combined with noncardiac operations without mortality or significant morbidity. An illustrative case report shows the interrelated nature of the coexisting disorders. The conclusion of this study is that, at times, various surgical procedures should be combined with coronary artery bypass grafting for a smoother, less complicated recovery. However, there are no hard and fast rules dictating combined procedures; each operation must be planned according to the existing conditions and needs of the individual patient.     

Simultaneous endoscopic radial artery and great saphenous vein harvesting for redo coronary artery bypass grafting. A report of two cases

Aim: An ageing population and increase in patient co-morbidities are forcing cardiac surgeons to meticulously consider the benefits and risks of respective conduits and their harvesting techniques. Case reports: Two cases of simultaneous endoscopic radial artery and great saphenous vein harvesting, for redo coronary artery bypass grafting, are presented. A shortage of venous conduits after previous bypass grafting, as well as the presentation of several risk factors of wound-healing complications, favoured simultaneous utilisation of both endoscopic techniques. Conclusion: Endoscopic vessel harvesting together with the pre-harvesting duplex study is able to gain not only high-quality conduits but also minimize the risk of wound-healing and neurological disturbances associated the saphenous vein and radial artery harvesting.     

The clopidogrel after surgery for coronary artery disease (CASCADE) randomized controlled trial: clopidogrel and aspirin versus aspirin alone after coronary bypass surgery [NCT00228423]

Background

Saphenous vein graft disease remains a major limitation of coronary artery bypass graft surgery. The process of saphenous vein intimal hyperplasia begins just days after surgical revascularization, setting the stage for graft atherosclerotic disease and its sequalae. Clopidogrel improves outcomes in patients with atherosclerotic disease, and is effective at reducing intimal hyperplasia in animal models of thrombosis. Therefore, the goal of this study will be to evaluate the efficacy of clopidogrel and aspirin therapy versus aspirin alone in the prevention of saphenous vein graft intimal hyperplasia following coronary artery bypass surgery.

Methods

Patients undergoing multi-vessel coronary artery bypass grafting and in whom at least two saphenous vein grafts will be used are eligible for the study. Patients will be randomized to receive daily clopidogrel 75 mg or placebo, in addition to daily aspirin 162 mg, for a one year duration starting on the day of surgery (as soon as postoperative bleeding has been excluded). At the end of one year, all patients will undergo coronary angiography and intravascular ultrasound assessment of one saphenous vein graft as selected by randomization. The trial will be powered to test the hypothesis that clopidogrel and aspirin will reduce vein graft intimal hyperplasia by 20% compared to aspirin alone at one year following bypass surgery.

Discussion

This trial is the first prospective human study that will address the question of whether clopidogrel therapy improves outcomes and reduces saphenous vein graft intimal hyperplasia following cardiac surgery. Should the combination of clopidogrel and aspirin reduce the process of vein graft intimal hyperplasia, the results of this study will help redefine modern antiplatelet management of coronary artery bypass patients.     

Free radical reaction products and antioxidant capacity in beating heart coronary artery surgery compared to conventional bypass

Oxygen-derived free radicals are important agents of tissue injury during ischemia and reperfusion. The aim of this study was to investigate changes in protein and lipid oxidation and antioxidant status in beating heart coronary artery surgery and conventional bypass and to compare oxidative stress parameters between the two bypass methods. Serum lipid hydroperoxide, nitric oxide, protein carbonyl, nitrotyrosine, vitamin E, and β-carotene levels and total antioxidant capacity were measured in blood of 30 patients undergoing beating heart coronary artery surgery (OPCAB, off-pump coronary artery bypass grafting) and 12 patients undergoing conventional bypass (CABG, on-pump coronary artery bypass grafting). In the OPCAB group, nitric oxide and nitrotyrosine levels decreased after reperfusion. Similarly, β-carotene level and total antioxidant capacity also decreased after anesthesia and reperfusion. In the CABG group, nitric oxide and nitrotyrosine levels decreased after ischemia and reperfusion. However, protein carbonyl levels elevated after ischemia and reperfusion. Vitamin E, β-carotene, and total antioxidant capacity decreased after ischemia and reperfusion. Significantly decreased nitration and impaired antioxidant status were seen after reperfusion in both groups. Moreover, elevated protein carbonyls were found in the CABG group. The off-pump procedure is associated with lower degree of oxidative stress than on-pump coronary surgery.     

Unanswered ethical and scientific questions for trials of invasive interventions for coronary disease: The case of single vessel disease

Trials in the 1990s demonstrated that medical therapy is as effective as invasive therapies for treating single-vessel coronary disease. Yet more recent studies enrolling patients with this condition have focused on evaluating only invasive approaches, namely, stenting versus coronary artery bypass surgery. Several ethical and scientific questions remain unanswered regarding the conduct of these later trials. Were they justified? Why wasn't a medical therapy arm included? Were subjects informed about the availability of medical therapy as an equivalent option? Was optimized medical therapy given prior to randomization? The absence of clear answers to these questions raises the possibility of serious bias in favor of invasive interventions. Considering that medical therapy is underutilized in patients with coronary disease, efforts should focus more on increasing utilization of medical therapy and proper selection of noninvasive interventions.     

Arterial end-to-side grafting in coronary artery bypass grafting: the Tector procedure

Background. The current treatment of choice in patients with three-vessel coronary disease is coronary artery bypass grafting. The use of the left internal mammary artery in bypass grafting has shown superior long-term outcomes compared with venous grafting. In our study we assess the safety and feasibility of all-arterial coronary artery bypass graft surgery using the procedure as described by Tector et al. in 2001.Methods. Between June 2001 and February 2007, we studied 133 patients eligible for non-emergency surgical revascularisation. Primary endpoints were death or re-infarction within a 30-day period. Secondary endpoints were the need for emergency coronary surgery, angioplasty and mediastinitis. Long-term follow-up had a mean duration of 33 months postoperatively.Results. All 133 patients were successfully revascularised, 98% with the off-pump technique. In 93% of the patients (n=124) full arterial grafting was achieved using both internal mammary arteries. Thirty-day mortality was 1.5% (n=2), ten re-thoracotomies were performed, one myocardial infarction and one case of mediastinitis were reported. In the next four years six additional patients died. Most of these deaths were due to non-cardiovascular causes. Two patients required angioplasty because of distal bypass graft failure and one for new native coronary artery disease. Conclusion. All-arterial bypass grafting using both internal mammary arteries with the technique as described by Tector is safe and feasible without excess deep sternal wound infections. Late major adverse cardiac events are rare and due to distal graft dysfunction, which can be treated by percutaneous coronary intervention. (Neth Heart J 2010;18:7-11.)     

Precision Incision: Robotic Coronary Revascularization via 3.9-cm Minithoracotomy

ABSTRACT: Coronary artery bypass grafting remains the treatment choice for coronary artery disease; but sternotomy, the most commonly used approach, compromises its benefits with postoperative morbidity, higher complication rates, and prolonged length of hospital stay. Despite this, minimally invasive and robotic-assisted technology has not been adopted or widely embraced because supporting literature on robotic-assisted coronary artery bypass grafting is extremely limited. Since 2005, the cardiothoracic surgical team at our institution has been developing and maturing an effective method using robotic harvesting of the left internal mammary artery (LIMA) and beating heart surgery through a minithoracotomy for coronary revascularization. This surgical technique involves precisely placing the robotic endoscopic port immediately over the left anterior descending (LAD) artery target site. The robotically harvested LIMA is secured to the epicardium at the LAD target, the robotic instruments are removed, and the endoscopic port site is enlarged slightly greater than 1 cm to become the minithoracotomy and allow for LIMA-to-LAD anastomosis. The other two robotic ports are used to complete the procedure without a need for additional incisions. This standardized method has been used in more than 750 patients, and since 2009, the last 377 consecutive non-rib-spreading minithoracotomy incisions measured a median of 3.9 cm (mean [SD], 4.16 [1.2748] cm; range, 2.3-12.0 cm). This "How I Do It" article describes our methods in detail and associated robotic nuances.     

体外和非体外循环冠脉搭桥术后老年患者肝肾功能变化

目的:分析常规体外循环冠状动脉搭桥术(CPBCABG)和非体外循环冠状动脉搭桥术(OPCABG)对60岁以上老年患者肝肾功能的变化及意义。方法:根据患者意愿及病情匹配原则将390例60岁以上患者分为常规体外循环下冠状动脉搭桥术组(CPBCABG组)(290例)和非体外循环下冠状动脉搭桥术组(OPCABG组)(100例)。所有患者术前肝肾功能均正常,无严重急性肝、肾功能不全。两组患者在年龄、性别、身体质量指数、体表面积、术前射血分数、术前肝肾功能及手术危险因素等方面无明显差异。两组患者分别于术前第三天和术后第三天抽血测定丙氨酸氨基转移酶(ALT),天冬氨酸转氨酶(AST),肌酐(CR)及尿素氮(BUN)值评价患者肝肾功能。结果:390例患者均进入结果分析。OPCABG组患者术后第3天ALT、AST、CR、BUN明显低于CPBCABG组,差异比较有显著性意义(P<0.05)。结论:冠状动脉搭桥术对肝肾功能均有一定的损害,由于非体外循环冠状动脉搭桥术避免了体外循环对肝肾功能的影响,因此对肝肾功能的损害较轻,减少了术后肝肾功能不全发生的机率。     

左旋精氨酸在冠脉搭桥术中心肌保护作用研究进展

冠状动脉搭桥术(Coronary artery bypass grafting,CABG)中发生心肌缺血再灌注损伤是难以避免的,而冠状动脉内皮损伤导致一氧化氮(nitrogen monoxidum NO)合成及释放减少是导致心肌缺血/再灌注损伤(Myocardial ischemia/reperfusion injury MI/RI)的重要因素。本文通过对左旋精氨酸(left-arginine,L-Arg)与NO、MI/RI之间的联系、L-Arg对MI/RI的保护作用及其机制、L-Arg-NO的心肌保护作用与剂量之间关系以及L-Arg在CABG中的临床应用等方面的研究进行综述,阐明提供外源性L-Arg通过L-Arg-NO通路促进体内NO的合成及释放,探讨左旋精氨酸在冠脉搭桥术中心肌保护作用的可行性。     

Endoscopic lesser saphenous vein harvesting for coronary artery bypass grafting: first reported case

Endoscopic vessel harvesting has become a widely used modality for harvesting venous and arterial conduits for coronary artery bypass grafting. Specifically, it has been used to harvest the greater saphenous vein, internal thoracic artery, and the radial artery. A case of endoscopic lesser saphenous vein harvesting for coronary artery bypass grafting is reported.     

Generalizing causal inferences from individuals in randomized trials to all trial‐eligible individuals

We consider methods for causal inference in randomized trials nested within cohorts of trial‐eligible individuals, including those who are not randomized. We show how baseline covariate data from the entire cohort, and treatment and outcome data only from randomized individuals, can be used to identify potential (counterfactual) outcome means and average treatment effects in the target population of all eligible individuals. We review identifiability conditions, propose estimators, and assess the estimators' finite‐sample performance in simulation studies. As an illustration, we apply the estimators in a trial nested within a cohort of trial‐eligible individuals to compare coronary artery bypass grafting surgery plus medical therapy vs. medical therapy alone for chronic coronary artery disease.