Sequential internal mammary-coronary artery bypass

A total of ten patients have undergone sequential bypass grafting of the internal mammary artery (IMA) to the coronary arteries at Osaka Medical College. Operative procedures included left IMA bypass to the left anterior descending (LAD) artery and its major diagonal branch in six patients; to the obtuse marginal branch and diagonal branch in three patients; and to the first and the second diagonal branches in one patient. The right internal mammary artery was concomitantly utilized in 4 patients and saphenous vein graft was also utilized in 6 patients. Postoperative angiographic studies were performed in nine patients within 6 months after operation and in all 18 sites of IMA anastomoses, the IMA sequential grafts were patent. Since sequential IMA-coronary bypass technique means the increase of arterial graft, we believe that this technique should be used for multivessel coronary revascularization especially in younger patients.     

Endarterectomy, vein patch, and mammary bypass of the anterior descending artery

Occasionally the left anterior descending (LAD) coronary artery contains such diffuse calcific atherosclerosis that an area suitable for distal anastomosis with the internal mammary artery (IMA) cannot be found. Additionally, the LAD of some patients contains multiple areas of stenosis, which would prevent free outflow from the IMA graft. In these cases the potentially increased operative risk of LAD endarterectomy is justified to avoid leaving poorly revascularized areas of anteroseptal heart. In an effort to provide the long-term patency benefits of IMA grafting for these patients without the technical difficulty of a lengthy IMA to LAD anastomosis, we have combined saphenous vein patch reconstruction with IMA bypass when LAD endarterectomy is required.     

Long-term blood flow potentials in sequential internal mammary artery grafts. Exercise thallium scan for myocardial perfusion study.

In two groups of patients, coronary artery bypass surgery for angina pectoris included internal mammary artery (IMA) sequential grafts (group I) or single grafts (group II). At postoperative angiography all grafts were patent. In addition, the patients received on average 1.8 vein grafts into other coronary arteries. The mean interval to postoperative follow-up was 9.5 years in group I and 9.7 years in group II. The preoperative incidence of acute myocardial infarction was 44% and 45% in groups I and II. Exercise thallium scan at follow-up showed IMA graft-related ischemia in 33% of the patients with sequential graft and in 64% of those with single graft (ns). Our results indicated that sequential IMA grafts functioned at least as well as single grafts and maintained adequate myocardial supply even 10 years postoperatively. Internal mammary arteries are superior graft material and can be recommended both as single and as sequential graft in coronary artery bypass surgery.     

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.     

Combined internal mammary artery graft for coronary artery revascularization

Five patients with multiple-vessel coronary artery disease underwent isolated coronary artery bypass grafting with a technique involving both internal mammary arteries and a small piece of interposed saphenous vein. The combined internal mammary artery grafts were used for sequential grafting. A total of 20 anastomoses were performed (average number, 4 anastomoses per patient). There were no operative deaths. Postoperative complications included reoperation for bleeding in 1 patient and diaphragmatic dysfunction in another. Postoperative coronary angiography 2 days before discharge (mean time, 10 days postoperatively) revealed that all the sequential anastomoses with the combined IMA graft were patent. Exercise tolerance tests performed 3 and 11 months postoperatively indicated excellent results and no ischemia. Based on this experience, we conclude that this method appears promising for multivessel coronary artery bypass grafting.     

Flow capacity of the canine internal mammary artery

The internal mammary artery has excellent long-term patency when used as a conduit for coronary artery bypass, and clinical and experimental studies have shown that blood flow through an internal mammary artery graft is satisfactory for most coronary artery branches. Multiple distal anastomoses from a single internal mammary artery, either with sequential anastomoses or with a Y-graft, might require additional blood flow through the vessel, and there has been concern that the flow capacity of the internal mammary artery is insufficient with these techniques. To better define the immediate postoperative flow capacity and pattern of the internal mammary artery, we performed experiments in seven dogs in which the left internal mammary artery was anastomosed to the circumflex coronary artery. In situ, blood flow in the internal mammary artery was 27 ml/min. Blood flow was 63 ml/min in the circumflex coronary artery and 42 ml/min in the left anterior descending coronary artery. After anastomosis of the left internal mammary artery to the circumflex coronary artery, the left main coronary artery was ligated; flow through the bypass graft increased to 92 ml/min, and systemic hemodynamics remained stable. Isoproterenol stimulation further increased flow through the left internal mammary artery graft to 160 ml/min. This study suggests that the canine internal mammary artery is capable of substantial early increase in flow and can, in fact, support the entire left coronary circulation.     

Bypass of the right and circumflex coronary arteries with the internal mammary artery.

Our experience with the internal mammary artery (IMA) for coronary bypass grafting in the past 3 years includes 323 grafts in 253 patients. After an initial group of IMA to left anterior descending (LAD) coronary artery grafts, we began using the IMA to bypass circumflex and small right coronary arteries (RCA). This report describes our experience with IMA bypass of coronary vessels other than the LAD. A total of 96 patients have had an IMA graft to the circumflex or RCA. Most of these patients had two or more bypasses. The mortality rate for this group has been 7 per cent, 7 of 96 patients. Postoperative angiography in 82 of 89 survivors has shown a patency rate of 98 per cent in 83 of 85 grafts studied. We conclude that the IMA is the vessel of choice for coronary artery bypass and that it can be used to bypass any of the main coronary arteries.     

Sequential internal mammary-coronary artery bypass

Since April, 1977, a total of eight patients have undergone sequential bypass grafting of the internal mammary artery (IMA) to the coronary arteries at our institution. The indication for this newly described procedure was either insufficient supply of adequate veins (four patients) or the presence of a diseased aortic wall (two patients). Operative procedures included left IMA bypass to the left anterior descending (LAD) artery and its major diagonal branch in six patients; to the obtuse marginal branch and distal circumflex artery in one patient; and to two consecutive sites on the LAD in one patient. All patients became angina-free after operation for a follow-up period lasting up to 6 years. Recatheterization studies were performed in four patients, in all of whom the IMA sequential grafts were found patent. We believe that IMA sequential grafting is an important option available to the cardiac surgeon in managing some patients with coronary artery disease.     

Technical Considerations and Early Results of Sequential Left Internal Mammary Artery Bypass Grafting to the Left Anterior Descending Coronary Artery System

The use of the internal mammary artery (IMA) as a coronary artery bypass graft conduit has recently been expanded to include sequential bypass grafting of multiple vessels. This has the theoretical advantage of allowing a greater percentage of myocardium to be revascularized with a conduit that has superior long-term patency rates. This article reviews technical considerations including maximizing IMA graft length and diameter, avoidance of an acute mediastinal or epicardial course, as well as anastomotic techniques for optimizing results of sequential IMA bypass grafting to the left anterior descending coronary artery system.     

From Vineberg to bypass: a "second-hand" internal mammary artery.

A patient operated upon 20 years ago for myocardial revascularization with two Vineberg procedures and one coronary artery bypass graft (CABG) on the right coronary artery had a recurrence of unstable angina due to the thrombosis of the left internal mammary artery (IMA) and the right CABG. The right IMA was patent but stenosed distally. Reoperation was performed with a direct end to side anastomosis of the patent right IMA onto the left anterior descending artery and a saphenous vein graft as a CABG on the marginal branch. We comment on the choice of this "second hand" IMA graft and the pathological appearances of the patent IMA.     

Coronary artery bypass with internal mammary and splenic artery grafts

Bypass grafts from the internal mammary artery (IMA) to the coronary artery, performed with small suture and optical magnification, have been found to have an extremely high late patency rate when compared with saphenous vein grafts. This is thought to be due to the use of autogenous artery instead of vein, the closer approximation in size between graft and artery, the fact that one anastomosis instead of two is necessary, and because microsuture with magnification produces a smoother anastomosis. This has led us to explore the use of the splenic artery for coronary bypass to the distal right coronary artery on the diaphragmatic surface of the heart.Three patients have had a right coronary bypass using splenic artery brought through the membranous portion of the diaphragm. Two of these patients also had an IMA-to-left anterior descending coronary artery bypass. Thus, autogenous artery bypass to the two most frequently obstructed coronary branches has been shown to be practical.     

Repair of damaged internal mammary artery

The use of the internal mammary artery (IMA) in coronary artery bypass graft surgery is an independent predictor of late survival in all subsets of patients and should not be denied to any subgroup. Therefore damage to the IMA during harvesting is a catastrophic complication after which the graft is usually discarded. We present here a simple and safe technique for repair of a damaged left IMA that allowed its rescue for grafting to the left anterior descending artery.     

Off-pump coronary bypass using interposed radial artery graft

We describe a patient with severely diseased ascending aorta and small internal mammary arteries, who underwent off-pump coronary artery bypass to the left anterior descending coronary artery and right coronary artery using composite arterial grafts consisting of the pedicled proximal internal mammary artery and interposed radial artery graft. The interposed radial artery graft provides advantages, such as making coronary anastomosis on the beating heart easier and to increasing the flow potentiality of the internal mammary artery.     

Free Internal Mammary Artery Graft: An Improved Surgical Technique

An improved method of free internal mammary artery (IMA)-to-ascending aorta anastomosis for coronary bypass is described. We interposed a small patch of vein with a suitable side-branch or branches in connecting the proximal end of a detached IMA or radial artery.Thirty-four free IMA-to-coronary artery bypasses were performed in 25 patients; 16 right IMA, 14 left IMA, and 4 radial arteries were used. Coronary angiographic follow-up studies performed in all patients between two weeks and six months after operation proved that all grafts were patent and showing a larger lumen than is usually seen in undetached IMA grafts. Concomitantly, marked relief of anginal pain was noted in all patients.Our experience with this technique is very encouraging. All patients are being followed to evaluate long-term graft patency.     

Internal mammary artery graft at reoperation: risks, benefits, and methods of preservation

To determine the effect of a prior internal mammary artery (IMA) graft on coronary artery bypass reoperation (CABR), we reviewed our experience with 410 consecutive patients: 313 received only saphenous vein grafts at initial coronary artery bypass grafting (CABG), and 97 received at least one IMA graft at CABG. Cardiac catheterization data before CABG were available in 110 patients (56 received only saphenous vein grafts, 54 received at least one IMA graft), allowing comparison of left ventricular function at CABG and CABR. Injury of the IMA graft occurred in 5 patients (1 death), but presence of an IMA graft was not an independent predictor of morbidity or mortality. Overall, the incidences of complications and deaths were higher in patients with saphenous vein grafts than in patients with IMA grafts, though not significantly so. Internal mammary artery grafts better preserved cardiac function: patients with IMA grafts had worse left ventricular function before CABG but better left ventricular function before CABR than patients with saphenous vein grafts. Left ventricular function deterioration from before CABG to before CABR was significantly less in patients with IMA grafts. We conclude that the risk of CABR is not increased by a previously constructed IMA graft and that left ventricular function is better preserved at CABR when an IMA graft was constructed at the initial operation.     

Early angiographic assessment of coronary revascularizations using the internal mammary artery. Apropos of a consecutive and prospective series of 180 bypass grafts]

This report describes a consecutive and prospective series of 136 patients, who underwent coronary bypass using the internal mammary arteries. Coronary angiography was routinely performed on all patients 8 days after surgery. A total of 137 operations (1 reoperation) were performed on 180 coronary arteries using 132 left internal mammary arteries and 25 right internal mammary arteries. Direct bypass was performed 133 times (73.8%), sequential bypass 23 times (25.5%) and free graft once. Bypass involved 1 coronary artery 89 times (65.4%), 2 coronary arteries 46 times (33.8%) and 3 coronary arteries in 1 case. The overall early success rate of internal mammary bypass in this series was 94.8% including 2 bypasses which were patent but non-functional. Of the 23 sequential bypasses, only 1 anastomosis out of 46 was not patent for a success rate of 97.3%. These good results are attributed to the large diameter of the mammary artery. Early postsurgical imaging is valuable for several reasons. It allows detection of surgical errors and improvement of the procedure. It enables distinction between residual primary surgical stenosis and secondary stenosis or genuine restenosis. It allows analysis of perioperative complications allows. No correlations between myocardial infarction and bypass obstruction were found. Finally, it permits endoluminal therapies such as thrombolysis (1 case in this series) and dilatation (2 cases). In conclusion, although we do not perform angiography routinely, our policy is to perform imaging in all cases of postoperative complications and after certain procedures such as sequential bypass.     

Postoperative radial artery angiography for coronary artery bypass surgery.

OBJECTIVE: To compare radial artery (RA) patency with internal mammary artery (IMA) patency for coronary artery bypass surgery in our early experience. METHODS: Symptomatic as well as asymptomatic patients with > or =1 RA coronary graft underwent postoperative angiography. Each anastomosis was considered separately. A string sign referred to a diffusely narrowed conduit, which did not fill the grafted coronary artery, as well as all occluded conduits. The raw value of P was adjusted for the testing of multiple hypotheses (P'). The patency data for each conduit was divided into two parts. 'Cut-off' stenosis for a conduit was the lowest dividing coronary stenosis at which a difference in patency rate with P< or =0.05 occurred. RESULTS: One-hundred-and-twenty-nine patients had 137 radial arteries and 157 angiograms. Only the most recent angiogram was analyzed for each patient at 13+/-0.7 months (n=129). Overall patency for arterial conduit 91% (n=404) was not different from venous conduit 91% (n=42) and patency for RA 90% (n=226) was not different from IMA 92% (n=178), (P'=0.999). Cut-off stenosis for RA was 70% and IMA was 40%. Patent arterial conduit had a mean coronary stenosis of 85% and non-patent conduit 64%, (P'<0.001). Right coronary territory patency was 82 vs. 94% for other territories (P'=0.022). No overall differences in patency were noted for patients with sequential anastomoses, symptoms or coronary disease at the anastomosis at the time of surgery. Reversible ischaemia was detected in the distribution of only two of 14 string signs in patients undergoing sestamibi exercise protocol following angiogram. CONCLUSION : There were no differences in patency between radial artery and internal mammary artery at 13 months post-operative. Lower coronary stenosis and right coronary territory predicted lower patency. The clinical importance of a string sign remains to be determined.     

Right gastroepiploic artery as a coronary bypass graft

Between November 1987 and April 1988, the right gastroepiploic artery (GEA) was used as a coronary artery bypass graft in 11 patients, 9 men and 2 women. In 1 of them, the GEA was used because no veins were available; in the others, the GEA was used to avoid the use of vein grafts. The GEA was anastomosed to the right coronary artery in all patients, and internal mammary artery grafts were used to bypass the left anterior descending and circumflex coronary arteries. All patients survived the operation. There were no early and, to date, there have been no late complications of the abdominal component of the operation. Postoperative coronary angiography showed a patent right GEA in 9 patients (82%). In 1 patient the GEA was occluded, probably because of an enlarged liver. If the long-term patency of right GEA grafts is similar to that of internal mammary artery grafts, wider use of this viable graft is indicated.     

非体外循环下双侧乳内动脉Y型桥的冠状动脉旁路移植术125例

目的总结非体外循环下采用双侧乳内动脉Y型桥进行完全心肌血运重建的冠状动脉旁路移植手术125例的近期疗效。方法2002年10月至2005年12月,完成125例不停跳非体外循环下双侧乳内动脉Y型桥的冠状动脉旁路移植手术,术中采用带蒂半骨骼化的方法分别取材左、右侧的乳内动脉,将左、右乳内动脉端侧吻合成Y型桥;在非体外循环下,应用序贯吻合的方法进行冠状动脉搭桥手术。结果全组125例患者共搭桥413支,平均搭桥支数3．3支／例。术中流量测定桥血管均通畅。全组患者无围手术期死亡。结论非体外循环下双乳内动脉Y型桥的冠状动脉旁路移植手术是安全、有效的方法,可以实现全动脉化的完全心肌血运重建,又避免手术中对升主动脉的操作,近期效果满意。     

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.