Anatomical study of the internal thoracic arteries; implications for use in coronary artery bypass graft surgery

Purpose

The feasibility of coronary artery bypass grafting using an internal thoracic artery (ITA) depends on the length of the graft with respect to the optimal route to reach the coronary target. The goal of this study was to assess the gain in length afforded by skeletonization and to evaluate the lengths of different pathways of the ITAs to the left coronary arteries.

Methods

The left and right ITAs were dissected out from 20 specimens and measured before and after skeletonization. Distance between the origin of the right ITA and the base of the left atrial appendage, corresponding to the proximal circumflex artery, was measured for both the transverse pericardial sinus and preaortic routes.

Results

Skeletonization gave a significant gain of length for both ITAs. Analysis showed no significant correlation between the ITA length and the height, weight, and BMI of specimens. We found no association between the length of the sternum and the length of skeletonized RITA or LITA. The anterior route of the skeletonized right ITA was shorter than the transverse pericardial sinus route in 18 cases. The average length to the circumflex artery territory was 132.8 ± 23.5 mm in front of the aorta and 150.5 ± 18.8 through the transverse pericardial sinus with a gain of length of 17.7 mm (p < 0.0001).

Conclusion

Skeletonization gave significant gains in length of both ITAs. The preaortic route for the skeletonized right ITA toward the circumflex territory was shorter than the transverse pericardial sinus route in 90 % of cases.

     

冠状动脉旁路移植术所用桡动脉与乳内动脉的超微结构比较

目的 桡动脉与乳内动脉的生物学特性及冠状动脉旁路移植术后的远期通畅率不同,本研究拟了解桡动脉与乳内动脉的超微结构差异及其对移植术后血管重构的可能影响。方法 在冠状动脉旁路移植术中采集桡动脉远端34例及乳内动脉远端11例。用电镜观察、比较两种动脉的内皮细胞及其脱落比例、内膜平滑肌细胞表型、基质分泌量、内中膜脂质和中层亚显微钙化的有无、中层平滑肌细胞的超微形态和排列。结果 桡动脉内膜较厚,内膜平滑肌细胞较多而密集。它在分泌态内皮细胞（47．1％,16／34）、合成型平滑肌细胞比例（14．4％）、内膜脂质（内膜44．1％,15／34;中膜58．8％,20／34）和基质分泌量增加（14．7％,5／34）方面高于乳内动脉（分别为27．2％,3／11;0．9％;内膜18．2％,2／11及中膜54．5％,6／11;9．1％,1／11）。动脉中膜可出现较多基质小泡及其钙化,而光镜水平未发现钙化,姑且称之为亚显微钙化。桡动脉的中层脂质和亚显微钙化与乳内动脉持平,内皮细胞的肿胀脱落却少于乳内动脉。两者的中层平滑肌细胞结构和排列未见显著差异。结论 冠心病患者桡动脉内皮细胞功能状态和内膜平滑肌细胞潜在的增殖能力高于乳内动脉,它可能参与移植术后重构,并与其远期通畅率较低有关。桡动脉获取中内皮保护较乳内动脉好,有利于通畅率的提高。     

Histologic study of coronary, radial, ulnar, epigastric and internal thoracic arteries: application to coronary artery bypass grafts

The biometry and the histology of coronary, radial, ulnar, epigastric and internal thoracic arteries were studied in order to investigate the cause of their occlusions in coronary bypass grafts and to improve the results of these bypass grafts. These various arteries were removed from 40 anatomical specimens (27 males and 13 females). We found a correlation between the internal calibers of the ulnar and coronary arteries in males. Intimal changes and the presence of atheromatous plaque were observed in coronary, radial and ulnar arteries, but never in the internal thoracic artery. Like coronary arteries and their branches, radial, ulnar and epigastric arteries are muscular arteries and ageing results in thickening of the intima, which becomes fibrotic with migration of myocytes from the media and duplication of the internal elastic lamina. The media becomes fibrous, hypertrophic or atrophic. In contrast, the internal thoracic artery is an elastic artery, like the aorta. Ageing is characterized by loss, over a variable extent, of one or several elastic laminae of the media and more marked intimal thickening. Although anatomically, the caliber of radial, ulnar, and epigastric arteries remains adapted to that of coronary arteries, the long-term patency of radial, ulnar and epigastric arteries used as grafts is related to their histological characteristics.     

冠状动脉旁路移植术后竞争血流对桥血管血流动力学的影响

目的 研究冠状动脉旁路移植术后,不同程度竞争血流对左侧胸廓内动脉管壁壁面切应力(wall shear stress, WSS)的影响。方法 基于阈值分割方法,通过采用SimVascular软件从CT图像提取并重建左侧胸廓内动脉(left internal mammary artery, LIMA) 左前降支（left anterior descending, LAD）吻合口模型。根据LAD的狭窄程度将竞争血流分为无竞争（100%狭窄）、轻度竞争（50%、75%狭窄）和高度竞争血流（0%、30%狭窄）3组。通过数值模拟方法观察上述情况下吻合口模型的血流动力学表现。结果 随着竞争血流的增加,LIMA桥血管管壁WSS逐渐降低,但是震荡程度逐渐增加。高度竞争血流组LIMA管壁平均WSS（0%狭窄：2.73 Pa,30%狭窄：2.85 Pa）明显低于轻度竞争血流组（50%狭窄：4.77 Pa,75%狭窄：6.01 Pa）和无竞争血流组(100%狭窄：8.64 Pa);而其震荡剪切指数(oscillatory shear index, OSI)（0%狭窄：0.206,30%狭窄：0.085）却明显高于轻度竞争血流组（50%狭窄：0.014,75%狭窄：0.013）和无竞争血流组(100%狭窄：0.006)。结论 当LAD狭窄程度小于50%时,大量的竞争血流会使LIMA管壁WSS明显降低,并且呈剧烈震荡的状态,这种不利的WSS表现会影响LIMA的远期通畅率,并造成手术远期疗效的下降。     

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。     

Changes of the beat amplitude power after partial left ventriculectomy and coronary artery bypass grafting

Partial left ventriculectomy (PLV) was originally introduced as a new surgical approach by patients with an end stage of cardiac disease. Coronary artery bypass grafting (CABG) is a standard procedures used in cardiac surgery. Multichannel ECG (MECG) measurements and body surface mapping (BSM) were used to analyse the normalised beat amplitude power maps (BAM) that reflect an overall cardiac activity. The resulting BAMs show that the amplitude of cardiac signals decrease for approximately 30% after the PLV and stay in the same level during the postoperative monitoring interval while after CABG no significant changes in BAM have been observed. In addition the electrodes from the body surface area above the left ventricle, where surgery was performed, show significant changes in beat amplitudes.     

非体外循环下冠状动脉旁路移植围术期血浆脑钠肽释放及其相关性研究

背景：B型脑钠肽已成为心血管疾病诊断重要的血清标志物,作为心血管疾病危险因素分层的重要因子。 目的：分析冠状动脉旁路移植前后B型脑钠肽与各项血流动力学参数的关系。 方法：选择30例冠心病行冠脉旁路移植患者,分为左室射血分数≥ 50%心功能正常患者13例;左室射血分数< 50%心功能不全患者17例。观察患者移植前1 d、移植后7 h、移植后1,3,5,7 d血浆B型脑钠肽水平变化趋势,分析移植前后B型脑钠肽与心功能各项指标的相关关系。 结果与结论：左室射血分数≥ 50%组患者冠脉旁路移植前后血浆B型脑钠肽水平显著低于左室射血分数< 50%组;组内比较移植后血浆B型脑钠肽水平均显著高于移植前(P < 0.05或P < 0.001)。患者冠脉旁路移植前B型脑钠肽水平与纽约心脏病协会心功能分级、左房内径、左室内径呈正相关(r=0.61;r=0．34;r=0．67);与左室射血分数、心排血量呈负相关(r=-0.75;r=-0.70)。患者移植后B型脑钠肽峰值浓度与出院前纽约心脏病协会心功能分级、超声心动图左室舒张末期内径、肺动脉压力呈正相关(r=0.72;r=0.70;r=0.45)。结果说明冠心病患者冠脉旁路移植前血浆B型脑钠肽质量浓度与左心室射血分数及左心室舒张末期内径有很好的相关性,能准确反映冠脉旁路移植前后的心功能状态。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

Perceived control and change in physical functioning after coronary artery bypass grafting: A prospective study

We determined if perceived general and health-related control predicted change in physical functioning after coronary artery bypass grafting (CABG) in 1,038 patients. Control and physical functioning were assessed prior to hospital discharge and physical functioning also was assessed 6 weeks and 6 months later. The repeated measures outcome was modeled using a one-way analysis of covariance with interaction terms for General and Health-Related Control x Time. The sample was primarily composed of Caucasian (94%) men (73%) with a mean age of 65 ± 11 years. Increasing health-related control was an independent predictor of positive change in physical functioning with a stronger effect in women. There was a nearly significant association between increasing general control and positive physical functioning change. Lack of significant interactions with time indicate that higher control has a beneficial impact on physical functioning change at 6 weeks and 6 months. Assessing control may help clinicians predict post-CABG physical functioning and may shape intervention efforts. This study was supported by a grant from the Ethel F. Donaghue Women’s Health Investigator Program, New Haven, Connecticut, and a grant from the Quality Care Research Fund, Aetna Foundation, Hartford, Connecticut. As a doctoral student, Dr. Barry was supported by a National Institute on Aging training grant (T32AG000153). Dr. Barry currently is supported by a National Institute on Aging training grant (T32AG1934), Research Training in Geriatric Clinical Epidemiology.     

The degree of lymphocytic mitochondrial transmembrane potential and blood magnesium concentrations during coronary artery bypass grafting.

Magnesium (Mg) plays an important role in lymphocyte function. Low blood concentration of Mg may result in intralymphocyte imbalance and in turn may be associated with intensified apoptosis of peripheral blood lymphocytes. Due to its multistage character; extracorporeal circulation (ECC) may augment Mg disorders adding to the above mentioned pathology. The aim of this study was to assess the correlation between lymphocyte apoptosis and Mg concentration in the blood during the course of coronary artery bypass grafting (CABG) and in the early postoperative period. METHOD: Twenty male patients undergoing CABG with ECC under general anaesthesia were included in the study. For detection of apoptotic lymphocytes in the circulation, inner mitochondrial transmembrane potential (deltapsim) was measured with the use of chloromethyl-X-rosamine (CMXRos) and flow cytometry. Spectrophotometry was used for Mg blood concentration measurements. Peripheral blood samples were obtained in seven stages: 1) just before anaesthesia, 2) 2 hours after the beginning of surgery, 3) immediately after surgery, 4) 12 hours after the beginning of surgery, 5) 24 hours after the beginning of surgery, 6) 36 hours after the beginning of surgery, 7) 54 hours after the beginning of surgery. RESULTS: The statistically significant increases of lymphocyte apoptosis were noted in stages from 2 to 7. Blood Mg concentrations decreased in stages 2 and 3. There was negative correlation between Mg blood concentration in stages 2 and 3 and the intensity of lymphocyte apoptosis in the stage 5. CONCLUSIONS: 1) CABG with extracorporeal circulation was associated with a decrease of magnesium concentration in the blood and an increase of lymphocyte apoptosis intensity. 2) The decrease of magnesium blood concentration may increase the degree of lymphocyte apoptosis. 3) Lymphocyte apoptosis after extracorporeal circulation has a two-phase course.     

Genetic polymorphisms of TP53 and FAS promoter modulate the progression of coronary artery disease after coronary artery bypass grafting: a gender-specific view

Introduction  

Progression of coronary artery disease (CAD) after primary coronary artery bypass grafting (CABG) is frequent and may lead to recurrent symptoms. Various data indicate that apoptosis is the main event occurring during development and progression of atherosclerotic plaque. Plaque vascular smooth muscle cells (VSMCs) are more sensitive than regular VSMCs to TP53-mediated apoptosis.     

Blood magnesium concentration and dopamine or dobutamine infusion demand in patients during CABG (coronary artery bypass grafting) with normovolemic haemodilution.

It is well known that magnesium (Mg) plays an essential role in cardiac protection. Mg has many beneficial effects on the myocardium and cardiac function, e.g. it improves contractility and reduces the number of cardiac arrhythmia episodes. The inotropically positive effects of Mg are interesting and worth stressing. High blood Mg concentration may result in an increase in cardiac contraction strength, which may be important for haemodynamic stabilization, and thus it is likely to decrease the demand for dopamine and dobutamine infusions. However, the exact determination of correlation between blood Mg concentrations and dopamine or dobutamine infusion demand is still unknown. The aim of the study was to assess the demand for dopamine or dobutamine infusion in relation to changes in blood magnesium concentrations in patients undergoing CABG (Coronary artery bypass graft) with extracorporeal circulation and normovolemic haemodilution. The study included 20 male patients, aged 53-70 (61.1 +/- 6.9) who underwent general anaesthesia and coronary artery bypass grafting (CABG) with extracorporeal circulation (ECC) and normovolemic haemodilution (NH) due to stable angina pectoris. The patients were retrospectively divided into three groups: A--patients who did not receive dopamine or dobutamine infusion, B--those receiving only D infusion in the doses dependent on their clinical state and C--those receiving DB infusion in the doses dependent on their clinical state. Mg was measured in 7 stages: 1) just before anaesthesia after the radial artery cannulation, 2) during normovolemic haemodilution and ECC, 3) immediately after surgery, 4) in the evening of the surgery day, 5) in the morning of the lst postoperative day, 6) in the evening of 1st postoperative day, 7) in the morning of the 2nd postoperative day. The spectrophotometric methods were used to determine Mg. The CABG procedure resulted in a decrease in Mg. Its level returned to normal in the evening of surgery day. The NH caused a similar Mg decrease in groups A, B and C, but these significantly low values of Mg were observed only in stage 2. There was no correlation between blood Mg concentrations and dopamine or dobutamine infusion demand. In conclusion: 1) The CABG procedure resulted in decreased blood magnesium concentrations. 2) The Mg changes do not correlate with dopamine or dobutamine infusion demand.     

术前他汀类药物治疗对冠状动脉旁路移植术后胸骨切口感染事件和主要心脑血管不良事件发生的影响

目的探讨冠状动脉旁路移植术(CABG)术前应用他汀类药物干预对患者术后胸骨切口感染事件发生率和主要心脑血管不良事件发生情况的影响。 方法选择2019年1月至12月于首都医科大学附属北京安贞医院心外科住院并行CABG治疗的患者880例。503例(57.2%)患者在CABG术前接受过他汀类药物治疗,将这些患者设为试验组;其余377例患者术前未应用他汀类药物,设为对照组。比较试验组和对照组患者的胸骨切口感染事件和主要心脑血管不良事件发生情况,再进行相应的风险因素分析。数据比较采用χ²检验、单因素方差分析和多元逻辑回归分析。 结果试验组患者CABG术后胸骨切口感染事件的发生率、主要心脑血管不良事件的发生率分别为2.0%、27.6%,与对照组(5.6%、35.0%)比较,差异均有统计学意义(χ²＝0.869、0.298,P＝0.005、0.022)。同时多元逻辑回归结果显示患者CABG术前应用他汀类药物治疗与术后胸骨切口感染事件显著下降具有独立相关性(OR 0.34,95%CI 0.16～0.74,P＝0.006)。此外,术前应用他汀类药物干预也与CABG术后主要心脑血管不良事件的发生率降低独立有关(OR 0.60,95% CI 0.44～0.81,P＝0.001)。 结论术前应用他汀类药物治疗能够降低患者CABG术后胸骨切口感染事件和主要心脑血管不良事件的发生。