Clinical and angiographic assessment of complex mammary artery bypass grafting

The internal mammary artery has become the coronary bypass graft of choice in recent years because of enhanced long-term patency. Along with this trend, sequential, bilateral, and free mammary grafts have been employed more frequently in an effort to maximize the number of distal internal mammary anastomoses. This approach of maximally using the internal mammary artery (complex mammary grafting) seems logical, but at present little information about patency of the newer types of internal mammary artery grafts is available to justify the more complicated procedures. Over a 15 month period, 207 patients underwent bypass graft angiography from 1 to 32 weeks after operation. This is an 85% restudy rate for a consecutive series of coronary bypass procedures. Patency was defined as complete filling of the graft and distal vessel bypassed. A total of 841 distal vessels were grafted, or 4.1 per patient. The overall patency rate was 91% for 503 distal vein graft anastomoses and 99% for 338 internal mammary artery grafts. Individual patency rates of distal anastomoses, expressed as number patent/total (percent patent), were as follows: simple vein grafts, 262/285 (92%); sequential vein grafts, 196/218 (90%); left internal mammary artery to left anterior descending coronary artery, 109/110 (99%); left internal mammary to circumflex marginal artery, 14/14 (100%); right internal mammary to right coronary artery, 19/20 (95%); right internal mammary to left anterior descending coronary artery, 10/10 (100%); right internal mammary to circumflex marginal artery via transverse sinus, 18/20 (90%); sequential left internal mammary artery to left anterior descending system, 133/134 (99%); sequential left internal mammary to circumflex marginal system, 15/15 (100%); free internal mammary artery, 9/9 (100%); free sequential internal mammary artery, 6/6 (100%). Of the 18 patent transverse sinus right internal mammary grafts to the circumflex marginal artery, three exhibited very slow flow and probably were not functional. The hospital mortality associated with internal mammary revascularizations was 0.4% for nonemergency cases and 3.1% for emergency procedures. On the basis of clinical and postoperative graft patency data, expanded use of more complicated types of mammary grafts seems justified. Function of the right internal mammary graft to the circumflex marginal artery was suboptimal, and this method has been discontinued. All other complex mammary techniques had excellent patency rates as compared to vein grafts, and these differences may become even more significant in the late postoperative period.(ABSTRACT TRUNCATED AT 400 WORDS)     

Complete arterial coronary revascularisation using radial artery conduit for double thoracic artery inlet flow: arterial sling operation.

BACKGROUND: Coronary artery bypass graft surgery with arterial revascularisation of all diseased coronary vessels is considered highly efficient because arterial grafts have an excellent long-term patency compared with venous grafts. However, problems to reach the infero-lateral wall with the in situ internal thoracic arteries usually require alternative techniques. We present the first results of a new surgical principle using a free radial artery segment to complete the arterial coronary revascularisation and concomitantly connect the internal thoracic arteries. METHODS: In patients referred for coronary bypass surgery and three-vessel disease an end-to-end anastomosis of the right internal thoracic artery and the radial artery segment preceded cardiopulmonary bypass, during which side-to-side anastomoses of the radial artery segment were used to revascularise stenotic branches of the right coronary and circumflex arteries. The left internal thoracic artery was used for revascularisation of stenotic branches of the left anterior descending artery, and finally an end-to-side anastomosis of the radial artery segment to the left internal thoracic artery was performed. Coronary artery blood flow was measured in 41 patients with Doppler flow probe. RESULTS: One hundred and ninety-two coronary anastomoses (an average of 4.2 per patient) were performed in 46 patients. We measured a mean total blood flow in the arterial sling graft of 104ml/min (range 35-221ml/min), compared with 69 and 68ml/min of the single inlet right and left internal thoracic arteries, respectively (P<0.01). Flow capacities of 104 and 120ml/min of the right and left internal thoracic arteries were measured during clamp of both the aorta and the contralateral internal thoracic artery. The mean crossclamp duration was 77min (range 51-113min). Postoperative angiography demonstrated patent graft anastomoses to all coronary arteries. There were no perioperative deaths or myocardial infarctions. One patient had a minor postoperative stroke. DISCUSSION: Complete arterial revascularisation can be achieved by the arterial sling operation with an acceptable crossclamp time and a high early rate of graft patency. The double arterial inlet provides a 50% higher blood flow to the beating heart and two-fold increase in the flow reserve compared with a single inlet. Although further research including long-term follow-up of this new principle is required, the present findings seem promising and suggest that the arterial sling operation has a potential role for complete arterial coronary revascularisation.     

Blood flow in composite arterial grafts and effect of native coronary flow

BACKGROUND: Total arterial coronary revascularization can be achieved by joining arteries together as a composite graft with the proximal left internal mammary artery as the only source of blood inflow. Proof of the capacity of this composite conduit to provide adequate blood flow to the coronary circulation is required. METHODS: The radial artery was anastomosed to the left internal mammary artery as a Y graft in 17 patients and all coronary arteries grafted. Intraoperative blood flow through the composite grafts was evaluated by the transit-time Doppler technique. RESULTS: Against no resistance, blood flow in the left internal mammary artery alone was 99 +/- 9 mL/min and rose to 173 +/- 16 mL/min when the radial artery was anastomosed as a Y graft. Composite-graft flow following grafting was 88 +/- 9 mL/min, 49 +/- 6 mL/min when the aortic clamp was removed and native coronary flow restored and 82 +/- 13 mL/min following weaning from cardiopulmonary bypass. The maximal potential flow through the composite graft was 2.3-fold (95% CI 1.6 to 3.2) greater than that after cardiopulmonary bypass. CONCLUSIONS: Total arterial revascularization, using a composite graft, provided a 2.3-fold reserve of blood flow to the coronary vascular bed through the grafts.     

Vasoactive drug effects on blood flow in internal mammary artery and saphenous vein grafts

The internal mammary artery is a dynamic coronary graft, whereas the saphenous vein graft is passive. Therefore, potential exists not only for beneficial vasodilation but also for catastrophic spasm of the artery. The purpose of this study was to examine blood flow in the internal mammary and saphenous vein grafts during infusion of drugs that are commonly used after cardiac operations. A canine right heart bypass preparation allowed precise control of cardiac output, blood pressure, and heart rate, which were maintained constant during drug infusion. Both the internal mammary and saphenous vein grafts were constructed so that they perfused the same coronary bed: They were anastomosed in a Y fashion to a ligated anterior descending coronary artery. Electromagnetic flow probes measured graft flow (with the other graft occluded) before and after 15 minutes of drug infusion. The order of drug infusion was randomized and changes were compared by tests for paired differences. Phenylephrine (2 micrograms/kg/min) decreased flow in both the internal mammary and saphenous vein grafts, whereas norepinephrine (0.1 microgram/kg/min) increased flow in both grafts. Epinephrine (0.05 microgram/kg/min) increased mammary artery flow 16% +/- 6% but decreased saphenous vein graft flow 9% +/- 7%. Nitroglycerin (1 microgram/kg/min) significantly increased internal mammary flow (36% +/- 13%), from 47 +/- 7 to 59 +/- 7 ml/min (p less than 0.01), whereas flow decreased significantly in the saphenous vein graft 14% +/- 3%, from 64 +/- 9 to 59 +/- 8 ml/min (p less than 0.01). Nitroprusside (1 microgram/kg/min) decreased mammary artery flow 12% +/- 2%, from 50 +/- 7 to 44 +/- 7 ml/min (p less than 0.01), but increased saphenous vein graft flow 25% +/- 8%, from 64 +/- 9 to 77 +/- 7 ml/min (p less than 0.01). All hemodynamic variables were unchanged, except for norepinephrine, which significantly increased the first derivative of left ventricular pressure. The results suggest that flow through the canine internal mammary artery is changed by the drugs commonly used in perioperative management. Epinephrine and nitroglycerin increased internal mammary artery flow and decreased saphenous vein graft flow, whereas nitroprusside had the opposite effect. The vascular reactivity of the internal mammary artery must be considered when these drugs are used after coronary revascularization.     

Preparation of the internal mammary artery graft. Which is the best method?

Early reports questioned the adequacy of flow of the internal mammary artery when used routinely as a bypass graft. "Adequate" mammary artery flow is now contested only in certain situations, that is, left ventricular hypertrophy, acute myocardial infarction, and reoperations. To compare the methods of mammary pedicle graft preparations with free mammary artery flow, we studied 31 patients who had the left internal mammary artery harvested for elective coronary artery bypass grafting. Group I comprised 14 patients whose mean body surface area was 1.91 m2. Systolic, diastolic, and mean arterial blood pressures, left atrial pressure, and heart rate were recorded and stabilized during flow measurements. Free flow of the internal mammary artery was measured before any pharmacologic manipulation and ranged from 5 to 44 ml/min (mean 18 ml/min). The grafts were sprayed and wrapped in sponges soaked in diluted papaverine solution (60 mg in 40 ml normal saline) for an average of 21 minutes. Free flow ranged from 10 to 108 ml/min (mean 51 ml/min). Intraluminal papaverine of the same dilution was then injected with hydrostatic dilatation. Immediate internal mammary artery flows rose from 150 to 333 ml/min (mean 229 ml/min). Group II comprised 17 patients who had internal mammary artery takedown under the exact conditions used in group I. Mean body surface area was 1.89 m2. Mammary artery pedicles were injected with diluted papaverine throughout their lengths with size 25 needles. After an average of 19.5 minutes, free flow ranged from 28 to 132 ml/min (mean 69 ml/min). Intraluminal diluted papaverine was then administered as in group I, and flows increased from 144 to 280 ml/min (mean 198 ml/min). The distal internal mammary arteries in both groups were 1.75 to 2.5 mm in internal diameter at the site of arteriotomy for flow measurement. This study shows that all mammary arteries are in spasm immediately after harvest and that flow is inadequate before any pharmacologic intervention. Although extraluminal vasodilators will increase free mammary artery flow, intraluminal papaverine followed by hydrostatic dilatation raises free flow to maximal capacity. Subsequent graft spasm has not been observed.(ABSTRACT TRUNCATED AT 400 WORDS)     

Competitive flow from a fully patent coronary artery does not limit acute mammary graft flow.

The shriveled, stenotic mammary graft sometimes observed after internal mammary artery (IMA) to coronary artery bypass grafting has been attributed to competitive flow from the insufficiently stenosed native coronary vessel. To study further the effects of native coronary artery competing flow on IMA graft flow, 10 dogs (mean weight, 23.5 +/- 3.69 kg) underwent coronary artery bypass grafting using the pedicled left IMA anastomosed to a normal, fully patent proximal circumflex (CFX) coronary artery. The procedure was performed through a left thoracotomy, off pump, using a brief local occlusion to perform the anastomosis. Native in situ IMA flow, CFX flow distal to the anastomosis, and IMA graft flow were measured using calibrated electromagnetic flow probes. When the CFX proximal to the anastomosis was occluded transiently, IMA flow increased to supply 100% of the previously measured distal CFX flow (60.2 +/- 7.9 mL/min). When both the IMA graft and CFX proximal to the anastomosis were patent, total distal perfusion was maintained (58.9 +/- 7.8 mL/min) and relative IMA graft flow (26.5 +/- 3.3 mL/min) was proportional to the relative diameter of the IMA graft to the native coronary artery (r = 0.96). The mean flow in the IMA in situ on the chest wall before its division was 23.8 +/- 8.1 mL/min. These results suggest that, at least acutely in a canine model, IMA graft flow is maintained above in situ levels even when grafted to a completely patent coronary artery and that acute competitive flow probably does not cause mammary artery shriveling.     

Myocardial rewarming mirrors intraoperative mammary artery graft function

BACKGROUND: The internal mammary artery (IMA) bypass graft provides a satisfactorily long-lasting blood supply to the myocardium. However, its initial flow capacity can be insufficient with subsequent regional myocardial ischemia. We evaluated a method to assess the IMA graft function intraoperatively. METHODS: Twenty-five patients with three-vessel coronary artery disease underwent coronary artery bypass grafting on cardiopulmonary bypass. The in situ IMA was grafted to the left anterior descending coronary artery (LAD) in combination with two saphenous vein grafts to the left circumflex and right coronary artery. Distal anastomoses were performed during cold intermittent blood cardioplegia. After unclamping of the aorta and of the grafted IMA, the temperature at the cardiac anterior and posterior side was measured during the first 5 minutes of warm reperfusion. RESULTS: A sufficient IMA graft function was expressed by a typical rise in temperature: the cardiac anterior and posterior sides showed a parabolic and exponential course, respectively. The rewarming velocity expressed as the first derivative of temperature over time led to a sharp and early peak for the anterior side, and a smaller and delayed peak for the posterior side. Insufficient IMA graft function could be recognized by an atypical temperature course. CONCLUSIONS: Temperature measurement of the heart during warm reperfusion after hypothermic cardioplegia can help to assess the effectiveness of the IMA-LAD graft function.     

Dopexamine increases internal mammary artery blood flow following coronary artery bypass grafting.

OBJECTIVE: Vasoactive agents and inotropes influence conduit-coronary blood flow following coronary artery bypass grafting (CABG). It was hypothesized that dopexamine hydrochloride, a dopamine A-1 (DA-1) and beta(2) agonist would increase conduit-coronary blood flow. A prospective randomized double blind clinical trial was carried out to test this hypothesis. DA-1 receptors have previously been localized to human left ventricle. METHODS: Twenty-six American Society of Anaesthesiology class 2-3 elective coronary artery bypass graft patients who did not require inotropic support on separation from cardiopulmonary bypass (CPB) were studied. According to a randomized allocation patients received either dopexamine (1 microg/kg per min) or placebo (saline) by intravenous infusion for 15 min. Immediately prior to and at 5,10 and 15 min of infusion, blood flow through the internal mammary and vein grafts (Transit time flow probes, Transonic Ltd.), heart rate, cardiac index, mean arterial pressure and pulmonary haemodynamics were noted. The data were analysed using multivariate analysis of variance. RESULTS: Low-dose dopexamine (1 microg/kg per min) caused a significant increase in mammary graft blood flow compared to placebo at 15 min of infusion (P=0.028, dopexamine group left internal mammary artery (LIMA) flow of 43.3+/-14.2 ml/min, placebo group LIMA flow at 26.1+/-16.3 ml/min). Dopexamine recipients demonstrated a non-significant trend to increased saphenous vein graft flow (P=0.059). Increased heart rate was the only haemodynamic change induced by dopexamine (P=0.004, dopexamine group at 85.2+/-9.6 beats/min and placebo group at 71.1+/-7.6 beats/min after 15 min of infusion). CONCLUSION: This study demonstrates that administration of dopexamine (1 microg/kg per min) was associated with a significant increase in internal mammary artery graft blood flow with mild increase in heart rate being the only haemodynamic change. Low-dose dopexamine may improve graft flow in the early post CABG period with minimal haemodynamic changes.     

Collateral blood flow between left coronary artery bypass grafts and chronically occluded right coronary circulation in patients with triple vessel disease. Observations during complete revascularisation of beating hearts.

OBJECTIVE: Preoperative measurements of collateral blood flow in patients with triple vessel disease and chronic occlusions of the right coronary artery do not, currently, ascertain the need to revascularise an occluded right coronary artery. We performed direct measurements of flow across left coronary bypass grafts to determine their contributions to collateral blood flow. METHODS: Collateral blood flow was scored preoperatively according to Rentrop in 13 patients with triple vessel disease and chronic occlusions of the right coronary artery who underwent complete, off-pump, surgical revascularisation. The transit-time flow through the left coronary grafts was measured before and after unclamping of the right coronary artery bypass graft. RESULTS: Unclamping of the right coronary artery bypass graft was associated with a 5.9+/-6.9ml/min (mean+/-SD) decrease in flow across the left circumflex territory (P=0.009), which was proportional to the preoperative Rentrop score (P=0.007). No significant change was observed in flow across the graft to the left anterior descending artery. CONCLUSIONS: Grafts to the left circumflex system are the only grafts that supply a significant, albeit modest amount of collateral blood flow to chronically occluded right coronary artery. These observations confirm that (1) most collateral flow after revascularisation is supplied by the native network, and (2) revascularisation of an occluded right coronary artery is fully justified.     

胸腔镜辅助冠状动脉旁路移植术的应用

【摘要】〓目的〓研究全胸腔镜下冠状动脉旁路移植术临床应用体会。方法〓2005年9月至2013年7月,冠心病患者共9例,男性5例,女性4例。均在电视胸腔镜下游离乳内动脉,行胸腔镜下冠状动脉旁路移植术。其中8例行非体外循环下左乳内动脉与前降支吻合,1例在体外循环下行房间隔缺损修补术,同期行右乳内动脉与右冠状动脉吻合。结果〓9例患者均手术成功。乳内动脉游离时间为31~47 min(39.3±5.9 min)。乳内动脉与冠状动脉的吻合时间为6~7 min(5.2±1.4 min)。术后ICU停留时间为2~4 d。术后9~12 d顺利出院。结论〓全胸腔镜下游离乳内动脉行冠状动脉旁路移植术近期效果良好。     

Symptomatic coronary-subclavian steal corrected by carotid-subclavian bypass

Angina recurred after a left internal mammary-to-left anterior descending coronary artery bypass graft. Subsequent development of a subtotal stenosis in the proximal left subclavian artery caused reversal of flow in the patent internal mammary artery graft, which produced an angiographic steal of myocardial perfusion. Angina and ischemia were relieved by reoperation, which consisted of left common carotid-to-left subclavian artery bypass in conjunction with right internal mammary-to-right coronary artery bypass and aorto-to-lateral circumflex coronary artery bypass with reversed saphenous vein.     

Comparison of the flow capacity of free arterial grafts and saphenous vein grafts for coronary bypass surgery

There is controversy regarding the flow reserve and capacity of arterial conduits to meet the needs of the myocardium. This study compared flow in 22 free arterial bypasses to 15 saphenous vein grafts in procedures involving twenty patients. To assess the maximal flow possible, (flow capacity) graft flow was measured using a calibrated pump while perfusing blood cardioplegia through the conduit and distal anastomosis during cardiac arrest (no competitive flow). This assessment was subsequently confirmed with whole blood during myocardial contraction while on cardiopulmonary bypass. Twenty-two free arterial grafts were used; 15 right internal mammary artery grafts, 4 right gastroepiploic grafts, 3 inferior epigastric artery grafts, and 3 sequential bypasses. Free arterial conduit flow ranged from 50 to 180cc/ml, with an average flow of 102.5+/-28.5ml/min as compared to saphenous vein graft flow, 102+/-28 ml/min. No correlation of flow with the conduit size was found. Arterial graft flow demonstrated a mild correlation with the size of the native coronary artery bypassed (R=0.47, P相似文献   

机器人微创非体外循环冠状动脉旁路移植术

目的 评价da Vincis机器人系统进行胸廓内动脉(IMA)游离、小切口非体外循环下冠状动脉旁路移植术的安全性和手术效果.方法 2007年1月到2011年3月,105例患者接受机器人IMA游离、小切口非体外循环下冠状动脉旁路移植术.其中男性77例,女性28例,年龄33～77岁,平均(59±10)岁.患者术前行64排CT检查评估IMA质量,2例患者左LIMA纤细或走行异常弃用.术者于操作台前、三维成像系统下遥控机器人游离IMA并完成动脉桥与靶血管的徒手吻合.其中4例患者旁路移植后接受了杂交技术于回旋支或右冠状动脉行支架植入术.术中均以超声血流检测仪测量桥血管的波形及血流.术后以冠状动脉造影或64排CT评估桥血管的通畅性,并进行随访.结果 所有患者成功接受上述手术,无手术死亡病例.术中平均IMA血管桥血流量为(21±13) ml/min.1例于术后第1天突发心跳骤停经抢救后痊愈,复查桥血管通畅.1例合并脑梗死患者术后肺部感染,痊愈后出院.其余患者无并发症发生.术中及术后出血少,术后恢复快.随访1～51个月,平均(30±12)个月.术后冠状动脉造影或64排CT复查未见桥血管狭窄或闭塞,心绞痛症状缓解.结论 机器人IMA游离、小切口非体外循环冠状动脉旁路移植术创伤小、疗效确切、安全性好,是微创冠状动脉再血管化的重要方向之一.     

Use of the inferior epigastric artery for coronary bypass.

Between December 1988 and April 1991, 74 free inferior epigastric arteries were used in 73 patients for coronary artery bypass grafts. In addition, 72 of the patients received a left internal mammary artery for single or sequential grafting to the left anterior descending system and 62 a right internal mammary artery to the circumflex or the right coronary artery. Twenty-seven patients had no saphenous vein available, and two had no suitable internal mammary artery; in an attempt to make a complete arterial revascularization, we chose the inferior epigastric artery as an alternative conduit in 24 young patients and in 10 reoperations; bilateral internal mammary artery dissection was avoided in four patients with impaired lung function and in six patients with selected two-vessel disease to spare one internal mammary artery. The technique for harvesting the inferior epigastric artery is described. Fifty-three inferior epigastric artery grafts were anastomosed to the distal right coronary artery or to its branches, 18 to the distal obtuse marginals of the circumflex artery (three as sequential grafts and one as a natural Y graft), and three to the left anterior descending system. The mean number of distal anastomoses is 3.60 per patient. Seventy proximal anastomoses of the inferior epigastric artery were made to the aorta and four to one internal mammary artery. There were four early deaths and one nonfatal myocardial infarction. Four abdominal wound hematomas needed surgical drainage. Sixty-one patients underwent angiographic study on postoperative day 10:59 of 61 inferior epigastric artery grafts (63 of 65 inferior epigastric artery distal anatomoses) and 111 of 111 internal mammary artery grafts (155 of 156 internal mammary artery distal anastomoses) were patent. Clinical follow-up of all the survivors (100% follow-up) could be obtained with a mean period of 9 months (1 to 28 months). There was no late cardiac death, no infarction, and all the patients were free of angina. Nineteen patients underwent a 6-month postoperative angiographic study. Seventeen of 19 inferior epigastric artery grafts were patent and 16 of 19 were intact; 34 of 34 internal mammary artery grafts (46 of 47 internal mammary artery distal anastomoses) were patent and intact. In conclusion, free inferior epigastric artery grafts can reach the diaphragmatic ischemic areas of the heart. The early patency rate and the clinical results are encouraging but only long-term evolution and evaluation can determine the true efficacy of the inferior epigastric artery graft as a reliable conduit for coronary artery bypass graft operations.     

A comparative study of the direct internal mammary-to-coronary artery anastomosis and the aortocoronary vein bypass graft

In a comparative follow-up study of the direct internal mammary-to-coronary artery anastomosis and the aortocoronary saphenous vein bypass graft, 202 dogs were observed for periods of up to 48 months. The 311 flow studies in the direct internal mammary-to-coronary artery anastomosis group showed 264 patent grafts. The average flow rates were 18.3 ml. in the right internal mammary-to-right coronary artery anastomosis group and 32.2 ml. in the left internal mammary-to-left circumflex coronary artery anastomosis group.No significant degenerative changes were detected in the internal mammary arterial wall during the four-year period; however, subintimal fibrous hyperplasia was observed in the vein wall within the 3-month postoperative period.     

Anatomical studies to support the expanded use of the internal mammary artery graft for myocardial revascularization

The internal mammary artery pedicle graft is frequently used for coronary bypass. Five internal mammary artery pedicle grafts, harvested but not utilized for coronary bypass, underwent histological examination. The histological studies demonstrated that the vasa vasorum were confined to the adventitia and did not penetrate the media of the internal mammary artery. These observations indicate that the media is nourished entirely from the lumen and suggest that harvesting the internal mammary artery as a free graft would not subject the wall of the artery to ischemic injury. Subsequent to these studies, we used the right internal mammary artery as a free graft to revascularize the distal circumflex coronary artery in 12 patients. The free graft was anastomosed to marginal branches of the circumflex and was then brought up to the left internal mammary artery pedicle graft and anastomosed end-to-side. This procedure has not resulted in excessive postoperative bleeding or sternal infections, and has relieved the anginal syndrome in all 12 patients.     

Expanded use of internal mammary artery graft for myocardial revascularization

To improve the early and late benefits of coronary artery bypass grafting, use of internal mammary artery grafts was expanded. The first 60 patients to receive two mammary artery-coronary artery anastomoses and supplemental saphenous vein grafts are reviewed. Altogether 210 grafts (3.5/patient) were performed, including 54 mammary artery grafts in situ, six of them as free grafts. In 12 patients the right internal mammary artery was placed through the transverse sinus to revascularize the circumflex artery, and the left mammary artery was placed to the left anterior descending artery. In the remaining 48 patients both internal mammary arteries were used to revascularize the left anterior descending and the right coronary artery. There were no perioperative deaths and no sternal infections. Postoperative complications included re-exploration for bleeding and diaphragmatic dysfunction. Late follow-up was complete. Of 60 patients observed for 1/2 to 4 years, 57 were asymptomatic. Exercise stress tests were performed in 58 cases and were normal in 56.     

Baseline flow in coronary bypass grafts

BACKGROUND: The purpose of the study is to estimate the total blood flow in coronary artery bypass grafts. METHODS: In a 3-year period 102 patients having a standardized coronary artery bypass grafting (CABG) with the left internal mammary artery (LIMA) anastomosed to the left anterior descending artery and a sequential vein grafted to the remaining diseased coronary arteries were included in the study, 21 females and 81 males. In females a mean of 3.9 anastomosis (range 2-5) were performed and in males a mean of 4.2 (range 2-6) were performed. Flow in the bypass grafts was measured with the transit-time method before termination of cardiopulmonary bypass. RESULTS: Females: LIMA 31 mL/min, vein graft 74 mL/min (26 mL/min per anastomosis), cumulated flow 105 mL/min. Males: LIMA 31 mL/min, vein graft 93 mL/min (29 mL/min per vein anastomosis), cumulated flow 124 mL/min. CONCLUSION: Conventional CABG may restore half of the normal resting coronary artery blood flow (250 mL/min).     

New Minimally Invasive Surgical Technique Using Arterial T-grafts for Treatment of Double-vessel Coronary Artery Disease: Experimental Study

Minimally invasive surgery has been used successfully in patients with single-vessel coronary artery disease (CAD), but there are no clinical reports of surgical techniques for the treatment of multivessel disease in this field using both internal mammary arteries (IMAs). Therefore a canine model has been established to demonstrate the feasibility of a minimally invasive surgical treatment of coronary artery double-vessel disease using both IMAs. Ten mongrel dogs underwent bilateral thoracoscopic preparation of both internal mammary arteries through small left lateral chest ports. Using the Port Access endovascular cardiopulmonary bypass system the right IMA (RIMA) was anastomosed as a free graft end-to-side to the left IMA (LIMA) as a T-graft. After induction of cardioplegic arrest the RIMA was anastomosed to the circumflex artery and the LIMA to the left anterior descending artery. All animals were weaned from cardiopulmonary bypass without inotropic support. The electrocardiogram showed sinus rhythm with no signs of ischemia. Intraoperative coronary angiography demonstrated patency of all anastomoses. The minimally invasive surgical treatment of double-vessel CAD using arterial T-grafts of both IMAs is thus feasible. Surgical trauma can be further reduced by harvesting the RIMA transmediastinally through the left lateral chest.     

经胸降主动脉微创冠状动脉旁路移植术

目的 探讨胸腔镜辅助左胸小切口、经胸降主动脉"Y"形旁路血管向心肌供血,实施非体外循环冠状动脉旁路移植术微创化的临床疗效.方法 66例冠心病病人,经左胸小切口开胸,胸腔镜游离左侧乳内动脉,经胸降主动脉"Y"形旁路血管向心肌供血,实施非体外循环冠状动脉旁路移植术,用瞬时流量测定仪检测旁路血管的通畅度.结果 平均手术(103,0±18.4)min.术后平均机械辅助呼吸(5.6±3.2)h,平均ICU滞留(37.3±7.6)h,平均胸腔引流量(190±75)ml,平均输血(150±50)ml,移植血管平均流量Qm为(27±7)mi/min,搏动指数(PI)为3.5±1.4,逆向血流百分比(%Insuf)为(7±5)%.全组病人无死亡,均治愈出院.随访12～48个月,病人病情稳定,身体状况良好.结论 该术式是微创冠状动脉旁路移植术的一个新途径.尤其适用于升主动脉存在钙化、扩张或粥样硬化斑块者,可避免升主动脉损伤、附壁斑块松动、脱落导致的脑栓塞或冠状动脉栓塞.安全、有效、创伤小.从真正意义上实现了冠状动脉旁路移植术的微创化.临床疗效显著,近期效果满意,远期效果有待进一步随访观察.