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OBJECTIVE--To assess current clinical practice in coronary artery bypass surgery and compare it with a previous survey conducted five years ago. SETTING--United Kingdom. DESIGN--Postal questionnaires were sent in March 1993 to 120 consultant cardiac surgeons currently performing coronary artery bypass surgery. 104 (87%) were returned by May 1993. RESULTS--The 104 surgeons who returned the questionnaire performed an estimated total of 25,234 coronary artery bypass operations in 1992 with an average case load per surgeon similar to that in 1987 (243 v 214, NS). The internal mammary artery was regarded as the conduit of choice by 101 surgeons (97%) and was used in 93% of bypass grafts to the left anterior descending coronary artery compared with 73% in 1987 (p < 0.001) but only in 7% of grafts to the circumflex and right coronary systems. There was also a significant increase in the number of surgeons using both internal mammary arteries (88% v 59%, p < 0.01) but only a small increase in those using the internal mammary artery as a sequential graft (55% v 44%, NS). The age of the patient remains one of the main contraindications to the use of the internal mammary artery (40%), together with insufficient mammary flow (42%), endarterectomy (22%), and unstable angina (17%). The right gastroepiploic and inferior epigastric arteries were used only occasionally (3%) when the internal mammary artery or the saphenous vein were not available. Most surgeons (96%) still advocate the use of aspirin to enhance graft patency, with 87% of surgeons continuing treatment indefinitely, compared with 50% in the previous survey (p < 0.001). As for methods of myocardial protection, 72% of surgeons used cardioplegic arrest whereas 28% preferred intermittent aortic cross clamping and fibrillation. CONCLUSIONS--It is the consensus among British cardiac surgeons that the internal mammary artery is the graft conduit of choice. Its use has been significantly extended over the past five years (1987 to 1992) suggesting a quick response to advancing scientific knowledge. The use of alternative arterial conduits is still limited, perhaps as a reflection of the relative lack of information on their long-term performance. The recently advocated technique of retrograde cardioplegia and continuous warm cardioplegia is not yet popular.

Patency rates and long-term clinical results after coronary artery bypass are superior when the internal mammary artery, rather than the saphenous vein, is used as a bypass graft. Four thousand forty-seven cardiac surgeons were surveyed to assess their theoretical preference of bypass graft, in comparison to their actual practice. The 750 surgeons performing myocardial revascularization who completed the questionnaire had done approximately 122,652 coronary artery bypass operations annually. Six hundred twenty-nine (84%) listed the internal mammary artery as the graft of choice for bypassing the left anterior descending coronary artery, whereas 114 (15%) listed the saphenous vein. Only about half (56%) of the surgeons actually used the internal mammary artery commonly, however, and only 228 (30%) used it in at least 90% of their operations. In actual practice, then, the internal mammary artery is often avoided in situations where it could be used as a coronary artery bypass graft. This practice can be expected to have a negative influence on late postoperative results. (The Texas Heart Institute Journal 1987; 14:139-143)

Coronary bypass grafts using the internal mammary artery usually have an excellent record of success and long term patency. We report a 42 year old man who initially presented with a history of atypical left sided chest pain, who had coronary artery bypass surgery for a severe stenosis in his proximal left anterior descending coronary artery (LAD) and moderate stenosis of his proximal circumflex artery, with his LIMA being grafted to his mid-LAD and a saphenous venous graft to the proximal LAD. He subsequently developed multiple stenoses in the LIMA graft which required coronary augioplasty and stenting, on more than one occasion, in view of very rapid restenosis within the LIMA graft.


Keywords: graft patency; left internal mammary artery grafts; restenosis; stenosis

Surgical coronary bypass has evolved continually, and recent developments favor performing coronary grafts with all-arterial conduits in order to obtain better long-term graft patencies. With bilateral internal mammary artery grafts and both radial arteries, four excellent arterial conduits exist for revascularization of the majority of multivessel disease patients, including those with valve disorders.

Using contemporary surgical techniques, it is possible to obtain greater than 95% overall long-term graft patencies that translate into better outcomes, including improved survival, freedom from myocardial infarction, percutaneous coronary intervention , and redo coronary bypass.

Two-thirds of patients receive a right internal mammary artery to the left anterior descending , a left internal mammary artery to the circumflex coronary artery system, and a radial artery to the right coronary artery Using newer management techniques, early postoperative complications, including the incidence of sternal infections, are extremely uncommon, and all-arterial grafts currently are used in over 75% of multivessel patients including those with concomitant valve disease. Because patencies and outcomes are so much better than with standard coronary bypass or percutaneous coronary intervention, referring physicians frequently favor all-arterial bypass as the primary therapy for patients with prognostically serious multivessel obstruction. Thus, all-arterial bypass could play an increasingly important role in the future treatment of severe coronary atherosclerosis.

Background

Standard coronary artery bypass graft surgery uses a single internal mammary artery and supplemental vein or radial artery grafts. Several observational studies have suggested a survival benefit with two internal mammary artery grafts compared to a single internal mammary artery graft, but this has not been tested in a randomised trial. The Arterial Revascularisation Trial is a Medical Research Council and British Heart Foundation funded, multi-centre international trial comparing single internal mammary artery grafting versus bilateral internal mammary artery grafting.

Methods/Design

Twenty centres in the UK, Australia, Poland and Brazil are planning to randomise 3000 coronary artery bypass graft surgery patients to single or bilateral internal mammary artery grafting. Supplemental grafts may be either saphenous vein or radial artery. Coronary artery bypass grafting can be performed as an on-pump or off-pump procedure. The primary outcome is survival at 10 years and secondary end-points include clinical events, quality of life and cost effectiveness. The effect of age, left ventricular function, diabetes, number of grafts, vein grafts and off-pump surgery are pre-specified subgroups.

Discussion

The Arterial Revascularisation Trial is one of the first randomised trials to evaluate the effects on survival and other clinical outcomes of single internal mammary artery grafting versus bilateral internal mammary artery grafting, and will help to establish the best approach for patients requiring coronary artery bypass graft surgery.

A multitude of vascular conduits are available to the Cardiac Surgeon performing Coronary Artery Bypass Graft operations. The Internal Mammary Artery, Radial Artery (RA), and the Long Saphenous Vein (LSV) have proven to be excellent conduits, especially in the current era of statin usage. However, previous stripping or varicosities of the LSV and calcification of the RA, coupled with the need for multiple vessel grafting, requires an alternative candidate. We describe a novel harvesting technique for bilateral simultaneous Short Saphenous Vein harvest and propose this, often forgotten vein, as a viable alternative conduit.

Over a 19-month period (from November 1985 to June 1987), 18 patients underwent open coronary endarterectomy combined with vein patch reconstruction and internal mammary artery (IMA) grafting. All 18 patients had disabling angina and severe, diffuse coronary atherosclerosis that prevented revascularization by conventional means. Thirteen underwent open endarterectomy of the left anterior descending coronary artery, and the remaining five had open endarterectomy of the right coronary artery. All patients received additional bypass grafts to other coronary arteries (2.6 grafts per patient). There was no operative mortality, but one patient had a perioperative myocardial infarction that was unrelated to the open endarterectomy. Postoperative angiography in 16 cases showed that only one of the grafts to the endarterectomized artery was occluded. After a mean follow-up of 8.7 months, all the patients but one were angina-free. No late deaths occurred.

Although the long-term clinical results and graft patency have yet to be evaluated, the early results of this series encourage us to continue using this technique in patients whose diffuse coronary artery disease is untreatable by conventional means. (Texas Heart Institute Journal 1987; 14:389-394)

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René G. Favaloro moved to the Cleveland Clinic in 1962 and with him came a wind of change that was to reshape cardiac surgery forever. With his cherished colleagues, Effler, Sones, Proudfit, Groves, Sheldon, and countless others, he contributed to the double internal mammary artery–myocardial implantation by the Vineberg method, and, subsequently, in May 1967, he reconstructed the right coronary artery by saphenous vein graft interposition. These milestones set the stage for aortocoronary saphenous vein bypass grafting in October 1967. Several other breakthroughs rapidly followed: the application of the bypass technique to the left coronary artery, the combination of coronary artery bypass grafting with left ventricular reconstruction and valve repair or replacement, and finally, by December 1967, a double bypass to the right coronary artery and the anterior descending branch of the left coronary artery. Emergency coronary artery bypass grafting in patients with acute myocardial infarction soon became Favaloro's next focus. In 1970, he was influenced by the work of George Green in New York City and began using the direct mammary–coronary anastomosis with a few modifications, which popularized it.

In June 1971, Favaloro decided to leave the Cleveland Clinic and return to Argentina, where he created a medical center, a teaching unit, a research department, and, finally, an Institute of Cardiology and Cardiovascular Surgery.

To all these medical achievements, add integrity, courage, honesty, and humility, and the result is a man who will never be forgotten.

Three groups of consecutive patients who had undergone primary elective coronary artery bypass operations were compared at 10 to 20 years of follow-up (mean, 13.6 years), in order to test the supposition that arterial conduits provide better long-term outcome than do the “standard” left internal mammary-to-left anterior descending coronary artery plus saphenous vein bypasses.

The arterial group was split into groups A (all arterial) and B (2 or more arterial grafts, plus saphenous vein grafts). Control group C comprised the standard operations.

The absence of saphenous vein conduit in group A was associated with fewer angiograms for symptoms, fewer reinterventions, and fewer cardiac deaths than those experienced in groups B and C.

We conclude that the survival and cardiac quality-of-life advantage found in group A is attributable to the exclusive use of arterial conduits.

Background

Coronary artery bypass grafting surgery is an effective treatment modality for patients with severe coronary artery disease. The conduits used during the surgery include both the arterial and venous conduits. Long- term graft patency rate for the internal mammary arterial graft is superior, but the same is not true for the saphenous vein grafts. At 10 years, more than 50% of the vein grafts would have occluded and many of them are diseased. Why do the saphenous vein grafts fail the test of time? Many causes have been proposed for saphenous graft failure. Some are non-modifiable and the rest are modifiable. Non-modifiable causes include different histological structure of the vein compared to artery, size disparity between coronary artery and saphenous vein. However, researches are more interested in the modifiable causes, such as graft flow dynamics and wall shear stress distribution at the anastomotic sites. Formation of intimal hyperplasia at the anastomotic junction has been implicated as the root cause of long- term graft failure.

Many researchers have analyzed the complex flow patterns in the distal sapheno-coronary anastomotic region, using various simulated model in an attempt to explain the site of preferential intimal hyperplasia based on the flow disturbances and differential wall stress distribution. In this paper, the geometrical bypass models (aorto-left coronary bypass graft model and aorto-right coronary bypass graft model) are based on real-life situations. In our models, the dimensions of the aorta, saphenous vein and the coronary artery simulate the actual dimensions at surgery. Both the proximal and distal anastomoses are considered at the same time, and we also take into the consideration the cross-sectional shape change of the venous conduit from circular to elliptical. Contrary to previous works, we have carried out computational fluid dynamics (CFD) study in the entire aorta-graft-perfused artery domain. The results reported here focus on (i) the complex flow patterns both at the proximal and distal anastomotic sites, and (ii) the wall shear stress distribution, which is an important factor that contributes to graft patency.

Methods

The three-dimensional coronary bypass models of the aorto-right coronary bypass and the aorto-left coronary bypass systems are constructed using computational fluid-dynamics software (Fluent 6.0.1). To have a better understanding of the flow dynamics at specific time instants of the cardiac cycle, quasi-steady flow simulations are performed, using a finite-volume approach. The data input to the models are the physiological measurements of flow-rates at (i) the aortic entrance, (ii) the ascending aorta, (iii) the left coronary artery, and (iv) the right coronary artery.

Results

The flow field and the wall shear stress are calculated throughout the cycle, but reported in this paper at two different instants of the cardiac cycle, one at the onset of ejection and the other during mid-diastole for both the right and left aorto-coronary bypass graft models. Plots of velocity-vector and the wall shear stress distributions are displayed in the aorto-graft-coronary arterial flow-field domain. We have shown (i) how the blocked coronary artery is being perfused in systole and diastole, (ii) the flow patterns at the two anastomotic junctions, proximal and distal anastomotic sites, and (iii) the shear stress distributions and their associations with arterial disease.

Conclusion

The computed results have revealed that (i) maximum perfusion of the occluded artery occurs during mid-diastole, and (ii) the maximum wall shear-stress variation is observed around the distal anastomotic region. These results can enable the clinicians to have a better understanding of vein graft disease, and hopefully we can offer a solution to alleviate or delay the occurrence of vein graft disease.

A technique of limited access, direct vision surgery for performing coronary artery bypass grafting with the internal mammary artery is presented in this preliminary report. The procedure is performed without cardiopulmonary bypass. To gain access to the left (or right) coronary artery and the mammary artery, segments of the 3rd and 4th costal cartilages are removed. Before the pericardium is opened, the mammary artery is dissected distally under the 5th costal cartilage and proximally under the 3rd costal cartilage to the level of the 2nd costal cartilage. If the left anterior descending coronary artery is suitable for bypass, it is dissected and the bypass graft is placed. Limited access coronary bypass has been completed successfully in 8 of our first 9 patients. All 9 patients have had relief of anginal pain. This experience proves that coronary bypass operations can be performed in selected lesions without a quiet, bloodless field, thus avoiding the potential complications of cardiopulmonary bypass.

A 38-year-old man underwent coronary artery bypass graft surgery for angina pectoris following myocardial infarction. During the following 28 years, he required two repeat coronary artery bypass graft surgical procedures, nine percutaneous coronary interventions and 17 coronary angiograms. His treatment included saphenous vein, left internal mammary artery and gastroepiploic artery grafting, percutaneous transluminal coronary angioplasty and intragraft thrombolytic therapy, directional coronary atherectomy, cutting balloon angioplasty, intracoronary stenting with bare-metal and drug-eluting stents, treatment for instent restenosis, stenting of the left main and circumflex coronary arteries and saphenous vein graft as well as intracoronary pressure wire diagnostics. In addition to his statin therapy, antiplatelets and angiotensin-converting enzyme inhibitors, he also underwent biventricular automatic implantable cardioverter-defibrillator implantation and atrioventricular node radiofrequency ablation for his impaired left ventricular function, ventricular tachycardia and rapid atrial fibrillation. The present unusual case represents almost ‘the whole nine yards’ of treatment that has become available to patients with coronary artery disease during the past 30 years of technological development.

A 77-year-old male former smoker with hypercholesterolemia and diabetes, who underwent coronary artery bypass graft surgery three years before admission and right carotid endarterectomy four years before admission, presented with recent-onset exertional chest pain. His medical history revealed that the chest pain was preceded by gradually worsening exertional claudication pain in his left arm when he was using crutches. The chest pain was similar to the pain he experienced before the coronary artery bypass graft surgery was performed. Coronary angiography and bypass graft imaging showed significant stenosis of the left subclavian artery proximal to the origin of the left internal mammary artery bypass, decreased flow in the left internal mammary artery with partial retrograde filling from the left anterior descending artery, and severe narrowing of the left vertebral artery with preserved centrifugal flow. Percutaneous stent implantation into the left subclavian artery was performed together with proximal balloon angioplasty of the left vertebral artery. The patient has been symptom free since the stent implantation.

Patients with single internal mammary artery (IMA) grafts along with saphenous vein grafts have been found to have fewer coronary events and longer survival after operation. To reduce bypass graft failure from intimal hyperplasia and atherosclerosis, as well as to improve results, three or more IMA grafts were placed in 215 patients from October 1982 through May 1985. Careful planning helped in bypassing the maximum number of coronary artery obstructions with arterial conduits. By using bilateral IMA grafts, sequential, and Y grafts, the number of IMA coronary artery anastomoses increases and the need for saphenous vein grafts decreases. Meticulous dissection and preparation of the entire IMA and proper construction of the anastomosis are essentials for these procedures to be successful. Two of the 215 patients died early and four died late. Ninety-five percent of the postoperative stress tests were negative and 92% of the 39 IMA grafts visualized in 13 patients studied postoperatively were patent. We found this to be a safe, challenging procedure that improved late bypass conduit success and prolonged survival.

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Background

Arterial grafts have patency rates superior to venous grafts in patients undergoing coronary bypass grafting surgery. Natriuretic peptides play a major role in vascular homeostasis. We hypothesized that natriuretic peptides might have different effects on arterial and venous conduits.

Methods

The relaxation responses and tissue levels of cyclic guanosine monophosphate (cGMP) after exposure to atrial natriuretic peptide, brain natriuretic peptide, and C-type natriuretic peptide were assessed in segments of internal mammary artery, radial artery, and saphenous vein obtained from the same patients at the time of bypass surgery (n = 12). Natriuretic peptide receptor (NPR) expression was assessed using immunohistochemistry and Western blotting.

Results

Relaxation of the internal mammary artery and radial artery to all the natriuretic peptides were similar, and greater than that of saphenous vein, correlating with increased tissue levels of cGMP in both arterial conduits. Relaxation responses to all three natriuretic peptides were nearly abolished in the presence of LY83583, an inhibitor of guanylyl cyclase. Exposure of the conduits to N(G)-Nitro-L-arginine methyl ester (nitric oxide synthase inhibitor) resulted in a modest but significant blunting of the relaxation responses. Expression of NPRA, NPRB and NPRC was strong in the endothelium and vascular smooth muscle layer of the internal mammary artery and radial artery, and was significantly less in saphenous vein.

Conclusions

Natriuretic peptides are potent vasodilators of the internal mammary artery and radial artery but not the saphenous vein. The relaxation response is mediated through guanylyl cyclase and nitric oxide synthase. These observations may provide additional insight into the mechanisms that account for superior patency of arterial conduits.

A man presented to the emergency room with recurrent episodes of abdominal pain. He had a history of coronary artery bypass grafting of the left internal mammary artery (LIMA) to the left anterior descending (LAD) artery and the right gastroepiploic artery to the posterior descending artery. After numerous gastrointestinal evaluations, a stress test was performed, which was positive. Coronary angiography showed a proximal occlusion of the LAD and right coronary artery and a normal functioning LIMA bypass. Aortography showed a 95% stenosis of the celiac trunk. Angioplasty and stent implantation of the celiac trunk was successfully performed. Six months later the patient was completely asymptomatic with a negative stress test. In conclusion, abdominal pain in patients who have undergone coronary artery bypass surgery using the right gastroepiploic artery should raise suspicion not only of a stenosis of the arterial conduit but also of a potential stenosis of the celiac trunk.

There is increased risk of systemic embolism during cardiopulmonary bypass in patients with a severely atherosclerotic ascending aorta. We report a coronary–coronary bypass in a 74-year-old man with a porcelain aorta. He underwent a proximal right coronary–distal right coronary artery bypass with a saphenous vein graft, combined with a pedicled arterial graft (left internal mammary artery) to the left anterior descending artery, in the presence of a beating heart without cardiopulmonary bypass. The patient survived without evidence of perioperative myocardial infarction or cerebrovascular accident. One year later, follow-up angiography showed graft patency with good distal runoff. Coronary–coronary bypass on a beating heart without cardiopulmonary bypass can be performed safely in a patient with porcelain aorta. (Tex Heart Inst J 2002;29:54–5)

Arterial grafting for the correction of coronary artery disease preceded the use of saphenous vein grafts, but the overwhelming popularity of the saphenous vein from 1970 to 1985 left the development of arterial grafting dormant. Excellent graft patency results from pedicled internal thoracic artery grafting and continued saphenous vein graft failure prompted our unit to explore complete arterial grafting with internal thoracic artery and radial artery grafts. One thousand and fifty-three patients who received a combination of internal thoracic artery and radial artery grafts were compared with 1,156 patients who received internal thoracic artery and saphenous vein grafts. All patients underwent primary coronary artery bypass surgery between 1995 and 1998. The early mortality and morbidity and the probability of survival at 2 years were similar in both groups of patients. Early graft patency studies of 35 radial artery grafts showed 33 (94%) were patent at a mean of 12 months. Complete arterial grafting using internal thoracic and radial arteries is safe and may provide a long-term benefit.

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We studied a series of 648 consecutive patients who underwent coronary artery bypass grafting for isolated primary disease of the anterior descending coronary artery. We evaluated the patients periodically during a long-term follow-up period of up to 17 years. We studied factors such as survival, survival without acute event (i.e., acute myocardial infarction, repeat coronary artery bypass, and percutaneous transluminal coronary angioplasty), and asymptomatic survival (i.e., survival without acute event or angina). We further analyzed these factors as they occurred in patients who received only saphenous vein grafts versus their occurrence in patients who received internal mammary artery grafts. There was 1 death in the early postoperative period (defined as 30 days or earlier after the operation). The 5-, 10-, and 15-year survival rates were 94.8%, 86.6%, and 72.2%, respectively. These survival rates are slightly better than those of an age- and sex-matched United States census population. In our series, the rates of survival, event-free survival, and asymptomatic survival were better, although not significantly so, in the group of 108 patients in whom the internal mammary artery was used as the bypass conduit. We conclude that patients who undergo coronary artery bypass grafting for isolated disease of the left anterior descending coronary artery enjoy normal survival rates, in comparison with the survival rates of an age- and sex-matched United States census population, through at least the 1st 16 postoperative years. Additionally, patients who receive an internal mammary artery bypass graft have slightly better rates of survival, event-free survival, and asymptomatic survival than do those who receive only saphenous vein grafts.

In situ right internal mammary artery is the graft of choice in reoperative off-pump coronary artery bypass grafting, as well as in primary on-pump coronary artery bypass grafting, unless the vessel has been used previously. However, there are not enough data about postoperative angiographic findings of the in situ right internal mammary artery in reoperative coronary artery bypass grafting with the off-pump technique.

From September 1993 through January 2004, we reviewed the postoperative course and the graft patency of 12 selected patients who underwent off-pump coronary artery bypass grafting reoperation only for revascularization of the left anterior descending artery, by means of a pedicled right internal mammary artery graft. All patients were evaluated clinically and by postoperative coronary angiography.

There were no early or late deaths during the mean follow-up period of 33.08 ± 30.05 months (range, 1–77 months). The mean interval from the 1st operation to the 2nd operation was 74.1 ± 57.01 months (range, 4.5–171 months).

Postoperative coronary angiograms of all patients showed a 100% patency rate for both in situ grafts and composite grafts.

We suggest that use of the in situ right internal mammary artery in off-pump coronary artery bypass grafting is a safe and reliable option for revascularizing the left anterior descending artery, especially in reoperation.

Over a 14-month period, 28 bovine internal mammary arteries (Bioflow, Bio-Vascular, Inc.; St. Paul, Minnesota, USA) were implanted in 20 patients at our institutions. In 8 patients, the bovine internal mammary artery was used to bypass coronary vessels: in 4 of these patients, coronary artery bypass grafting was performed because of coronary disease (1 type-I aortic dissection); in the other 4 (all with aortic dissection), the modified Bentall technique was used for coronary artery reimplantation. In the remaining 12 patients, the bovine artery was used in vascular surgery: as a graft for lower-extremity occlusive disease (4 patients), arteriovenous fistula (2 patients), and aorticorenal bypass (1 patient); and as a patch to the carotid bifurcation or the common femoral artery in association with endarterectomy (5 patients). The 21 bovine grafts were all 5 mm in diameter; the 7 bovine patches were 4 mm. Of the 8 coronary bypass patients, 2 who underwent coronary artery bypass grafting had acute postoperative myocardial infarctions, and 2 who underwent the modified Bentall technique died in surgery. Follow-up angiography showed complete bovine internal mammary artery graft occlusion in 2 patients; 2 symptom-free patients refused examination. Of the vascular surgery patients, 1 with mild left leg claudication had graft occlusion, shown by angiography, 4 months after surgery. Renal scintigraphy performed in the patient with aorticorenal bypass 4 months after operation showed no blood flow to the kidney. Two patients died for reasons unrelated to bovine mammary artery grafting. The remaining patients are well and free of complications. In view of the high incidence of early occlusion, we do not recommend use of the bovine internal mammary artery graft in coronary surgery. In vascular surgery, the results are more encouraging; however, studies comprising a larger number of patients and longer follow-up are needed to determine whether the use of the bovine internal mammary artery graft can be recommended.

Coronary subclavian steal syndrome with retrograde blood flow in the left internal mammary-coronary bypass graft is a rare but severe complication of cardiac surgery. The authors present a case of a 68-year-old man after coronary-artery bypass grafting using an internal mammary artery. He had been suffering from angina pectoris for the last several years before surgery. The patient was resuscitated at home by emergency medical service because of primary ventricular fibrillation due to an acute myocardial infarction 5 years after surgery. An occlusion of the left subclavian artery with the retrograde blood flow in the left internal mammary coronary bypass was found. This could have been the cause of insufficiency in coronary blood flow and ischemia of the myocardial muscle. The subclavian artery occlusion was successfully treated with percutaneous transluminal angioplasty and implantation of 2 stents. The patient remained free of any symptoms 2 years after this procedure.

Thirty three patients with coronary artery disease undergoing combined myocardial revascularisation with internal mammary artery and saphenous vein grafts underwent angiographic studies up to 10 years after operation. Each patient had one internal mammary artery graft and one or more saphenous vein grafts. Eleven symptom-free patients, studies one month to five years (mean 1.9 years) after operation, had intact internal mammary artery and saphenous vein grafts in a good state of preservation. Of the six patients developing symptoms within the first year after surgery, three had evidence of poor flow in the internal mammary artery graft because of large side branches and the other three had stenosis or occlusion of the saphenous vein grafts. Sixteen patients developed symptoms after several years free of symptoms and were studied three to 10 years (mean six years) after operation. Of the 23 saphenous vein grafts in this group, 17 (74%) were either occluded or severely stenosed and six (26%) were in good condition. One internal mammary artery graft was occluded and the remaining 15 were in good condition. Saphenous vein graft failure was the predominant cause of late development of symptoms in patients with combined revascularisation. Long term performance of the internal mammary artery grafts is far superior to the saphenous vein grafts.

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This second report in the series on coronary artery bypass presents the authors experience and personal views on the internal thoracic artery (ITA) which date to 1966. There has been a very gradual evolution in the acceptance of this conduit which was initially compared with the saphenous vein and viewed as an improbable alternative to it. As is common with concepts and techniques which are 'outside the box' there was skepticism and criticism of this new conduit which was more difficult and time consuming to harvest for the surgeon who had to do it all. It was viewed as small, fragile, spastic and its flow capacity was questioned. Only a few surgeons employed it because of these issues and some of them would frequently graft it to the diagonal artery as it was thought not to supply adequate flow for the left anterior descending unless it was small. After a decade, angiographic data revealed superior patency to vein grafts. Even this evidence and survival benefit reported a few years later did not convince many surgeons that their concerns about limitations justified its use. Thus widespread adaption of the ITA as the conduit of choice for the anterior descending required another decade and bilateral use is only now expanding to more than 5% of patients in the US and somewhat faster in other countries.

Background and Objectives

Arterial grafts have a better long-term patency rate than saphenous vein (SV) when used in off-pump coronary artery bypass surgery (OPCAB). However, arterial grafts in elderly patients are often diseased. We sought to compare the early outcomes achieved by using the two different types of composite grafts.

Subjects and Methods

We conducted a randomized trial to compare radial artery (RA) and SV composite grafts based on the in situ left internal mammary artery in 60 elderly (>70 years old) patients, who were scheduled to undergo OPCAB. Clinical outcomes and 1-year postoperative CT angiography results were compared. The quality of the conduit was evaluated by employing vascular ultrasonography, optical coherence tomography (OCT), and histologic examination.

Results

No differences in immediate postoperative morbidity and mortality were observed between the two groups. Early postoperative CT angiography revealed a SV patency rate of 100%, which was not different from that of RA composite grafts (99.1%). CT angiography after a year showed an overall patency rate of 96.3%. The overall patency rate of the SV group at 1 year was 94.7%, which was similar to that of the RA group (97.4%). Also, there was no difference in overall survival rate between the two groups. Vascular ultrasonographic images showed strong correlations between OCT and histopathology.

Conclusion

Our analysis of early outcomes revealed that the SV could be used as an alternative composite graft to the RA in elderly patients. Vascular ultrasonography is an accurate, real-time, and reproducible method for assessing the quality of the RA conduit.