Risks of bilateral internal mammary artery bypass grafting

Although use of one internal mammary artery (IMA) for coronary artery bypass grafting does not appear to be associated with increased risk, the results with both IMAs are less certain; the potential for a higher incidence of sternal wound infection as a result of devascularization of the sternum is a major concern. During a 42-month interval ending July 1988, 1,566 patients had coronary artery bypass grafting alone or in combination with other procedures: 633 received only vein grafts, 687 had unilateral IMA grafting, and 246 had bilateral IMA grafting. The IMA patients were younger, were more often male, had better cardiac function, and underwent fewer emergent, urgent, or combined procedures than the patients receiving vein grafts (p less than 0.05). Thirty-day mortality was lower among the IMA patients (unilateral IMA group, 2.8%; bilateral IMA group, 3.7%; and vein graft group, 7.9%; p = 0.001). With the exception of sternal wound problems, occurrence rates for postoperative complications among the IMA patients did not differ significantly from or were lower (p less than 0.05) than those among the patients with vein grafts. Sternal infections occurred with greater frequency among the bilateral IMA patients (6.9%) than among the unilateral IMA (1.9%) or vein graft (1.3%) patients (p = 0.001). By univariate analysis, obesity, diabetes, bilateral IMA grafting, and need for prolonged (greater than 48 hours) mechanical ventilation were associated with a significantly higher incidence of sternal infection (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Bilateral internal mammary artery for coronary revascularization. Early experience of 100 cases

One hundred cases are presented in which both right and left internal mammary artery (IMA) were used as coronary bypass grafts. Special indications were thrombosis of previous venous graft (14 cases), poor venous resources (10) and small-vessel (probe less than 1.5 mm) disease (34), but bilateral IMA was used also for routine revascularization (42 cases). The total 212 distal IMA anastomoses included 12 jump grafts, three free grafts and seven thrombendarterectomies. There were 3.8 distal anastomoses per patient, 2.1 with IMA and 1.7 with vein graft. The right IMA was preferably inserted into LAD and the left into diagonal or obtuse marginal coronary artery. Excessive postoperative bleeding was the only major complication attributable to bilateral IMA grafting in the 97 survivors of surgery. In routine revascularization the procedure involved minimal morbidity and no mortality. The superiority of the IMA as regards long-term patency is widely recognized. Since many thrombosed vein grafts will require replacement, we believe that bilateral IMA grafting will become common, and it is also an option when no suitable vein is available.     

Important anatomical and physiological considerations in performance of complex mammary-coronary artery operations

One or more internal mammary artery (IMA) anastomoses were performed in 87% of 692 consecutive coronary artery bypass operations performed over a 20-month period. One IMA was used in 68% (N = 469) and both IMAs were used in 19% (N = 130). Only saphenous vein grafts were used in 13% (N = 93). The mean number of anastomoses (all types) was 3.5. Fifty-seven patients were having a reoperation; bilateral IMA grafting was performed in 23% (N = 13). In 60 patients, 3 or more IMA anastomoses were performed: 3 IMA anastomoses, 50 patients; 4, 9 patients; and 5, 1 patient. In 27 patients, repeat coronary arteriography was performed within 30 days of operation to evaluate dynamics of IMA, saphenous vein, and native coronary artery flow. Major flow or all flow was through the graft (vs. the native coronary artery) in 62% of in situ IMA bypass grafts, 86% of free IMA grafts and 94% of saphenous vein grafts. Hospital mortality excluding patients having reoperation was 1.7% (11/635); it was less than 1% for patients having either single IMA grafting procedures (4/437) or bilateral IMA grafting procedures (1/117). Hospital mortality for patients receiving only saphenous vein grafts was surprisingly high, 7.4% (6/81). Major determinants of flow through the in situ IMA sequential graft are the size and flow of the IMA, the degree of proximal native coronary artery narrowing, the distally grafted to proximally grafted coronary artery size ratio, and probably the size of the side-to-side anastomosis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Internal mammary artery bypass grafting: influence on recurrent angina and survival in 2,100 patients

Internal mammary artery (IMA) bypass grafting to the anterior descending coronary artery was performed in 2,100 patients between January 1978 and July 1986. The average number of additional saphenous vein grafts (SVGs) per patient was 1.8. During the same period, 1,753 patients underwent coronary artery bypass grafting using an SVG (average number of grafts per patient, 3.2). The average patient age was similar: 62.3 years for IMA grafts and 64.7 years for SVGs. Men constituted two thirds of each group. Left ventricular function was impaired (ejection fraction less than 45%) in 1,071 (51%) of IMA grafts and 847 (48.3%) of SVGs. Other aggregate risk factors, ie, elevated blood pressure, diabetes mellitus, previous myocardial infarction, and congestive heart failure, were similar in each group. Operative results and postoperative mortality of the IMA and SVG patients were comparable. However, the long-term probability of cumulative survival and occlusion-free survival were significantly greater and the probability of recurrent angina and reoperative coronary artery bypass grafting were significantly less in IMA graft patients (p less than 0.015). The relative risk of occlusion in an SVG was 4 to 5 times greater than that of the IMA graft. These data indicate that a patent IMA graft to the anterior descending coronary artery protects against recurrent angina and death from cardiac-related causes, and that the IMA should be the conduit of choice.     

Application of ultrasonic aspirator for dissection of the internal mammary artery in coronary artery bypass grafting

The low-power ultrasonic aspirator was used for the dissection of the internal mammary artery (IMA) in 20 patients undergoing coronary artery bypass grafting. Harvesting time was shorter and the amount of bleeding was less than with the ordinary method. The short-term patency rate (1 to 6 months) for those IMA grafts was 95% (19 of 20 remained patent). These results have encouraged us to use the ultrasonic aspirator routinely for IMA dissection.     

Pleuropulmonary morbidity: internal thoracic artery versus saphenous vein graft

Although use of the internal thoracic artery (ITA) for coronary artery bypass grafting results in superior graft patency and improved patient survival, our initial clinical observations suggested an increased incidence of pleuropulmonary morbidity with its use. One hundred consecutive patients with left ITA grafts were studied prospectively and compared with a consecutive retrospective group of 100 patients undergoing coronary artery bypass grafting with saphenous vein grafts only. Preoperative, postoperative day (POD) 2, POD 6, and postoperative week 8 chest roentgenograms were analyzed for atelectasis and effusion. Postoperative left lower lobe atelectasis was common in both groups on both POD 2 (saphenous vein, 43%, versus ITA, 53%; not significant) and POD 6 (saphenous vein, 40%, versus ITA, 41%; not significant). There was a significantly higher incidence of pleural effusion on POD 6 in the ITA group (84% versus 47%; p less than 0.05) but most of these were small. There was more chest tube drainage (1,413 versus 1,028 mL; p less than 0.01) and a greater need for secondary thoracostomy or thoracentesis (4% versus 0%) in the ITA group. The left pleural space was opened in 67 of the 100 ITA patients but pleurotomy did not appear to influence postoperative morbidity. We conclude that use of the internal thoracic artery for coronary artery bypass grafting results in a small but significant increase in pleuropulmonary morbidity.     

Myocardial revascularization with internal mammary artery graft: analysis of early and late post-operative respiratory morbidity]

To evaluate the respiratory morbidity resulting from myocardial revascularization with internal mammary artery (IMA) graft, we reviewed 153 patients operated on between April and November 1988. There were 124 men with a mean age of 61 years. A bilateral IMA graft was used in 30 patients (20%). During the harvesting of the mammary graft, the homolateral pleura was systematically opened. Acute respiratory failure was more frequent in patients with bilateral IMA (13%) than in patients with unilateral IMA graft (3%) (p less than 0.05). Consequently, the mean duration of mechanical ventilation was longer in patients with bilateral IMA graft: 56 versus 23 hours (p less than 0.05). Lung volume measurements were altered according to a restrictive pattern. On the 9th post-operative day, forced vital capacity was reduced to 59.6% of the pre-operative value in patients with unilateral IMA and to 47.1% in patients with bilateral IMA graft (p less than 0.001). Late results were obtained in 111 patients. After a mean follow-up of 7 months, forced vital capacity was still reduced to 86.8% of the pre-operative value in patients with single IMA and to 78.1% in patients with bilateral IMA graft (p less than 0.001). In conclusion, respiratory morbidity is not negligible. Bilateral IMA grafting should generally be reserved to young patients (less than 65 years) with normal pre-operative pulmonary function tests.     

Coronary Artery Grafting with the Saphenous Vein or Internal Mammary Artery: Comparison of Late Results in Two Consecutive Series of Patients

In two series of consecutive patients who underwent coronary artery grafting with the saphenous vein or the internal mammary artery (IMA), angiographic studies were conducted two weeks and one year after operation. The early patency rate was 91.8% in 184 vein grafts and 97.4% in 38 IMA grafts. Late patency was 93.1% in 143 vein grafts and 90.9% in 33 IMA grafts. Thus, the cumulative patency rate at one year was 84.9% for vein grafts and 88.3% for IMA grafts.The incidence of severe narrowing at the site of anastomosis was 2.2% in vein grafts and 7.9% in IMA grafts; the rate of occlusion of the distal limb of the recipient coronary artery was, respectively, 4.3 and 7.9%. Diffuse reduction in the caliber of grafts at one year was less frequent with IMA grafts (12.7 versus 6.6%). On the other hand, blood flow was significantly higher in vein grafts: 67.4 versus 45.2 ml per minute (p < 0.001). Blood flow in IMA grafts whose caliber was larger than that of the recipient coronary artery was significantly higher than flow in IMA grafts with a caliber equal or inferior to that of the coronary artery: 63.1 versus 32.7 ml per minute (p < 0.001).Although cumulative patency rates at one year were comparable in both series, because only one-third of the IMAs were larger than their recipient coronary arteries, flow was somewhat restricted in the other two-thirds. This suggests that the IMA does not constitute the better bypass conduit and, unless it is of large caliber, preferably should be used in the grafting of small coronary arteries or those with limited runoff.     

Internal mammary artery grafts: technical factors influencing patency

Eight hundred fourteen patients with internal mammary artery (IMA) coronary artery bypass grafts have been restudied 961 times with coronary arteriography, primarily to evaluate the patency of the grafts in the setting of symptomatic coronary occlusive disease. Their records were reviewed to assess graft patency as related to the technical aspects of coronary artery bypass surgery. Patency was evaluated using life-table analysis of the data. The method of harvesting the IMA played no role in patency. The left anterior descending coronary artery was the recipient coronary artery with the highest patency rate. The left IMA had a significantly higher patency rate than the right IMA. As a group, the IMAs had a significantly higher patency rate than saphenous vein grafts. However, there was no difference between right IMA grafts and saphenous vein grafts. The mammary artery grafts that remained patent throughout the study had a significantly higher blood flow after bypass than did those that became occluded (43.0 +/- 0.9 versus 28.9 +/- 1.8 ml/min; p less than .001).     

Twelve-year experience with bilateral internal mammary artery grafts

A 12 1/2-year experience with 227 patients who underwent coronary revascularization with bilateral internal mammary artery (IMA) and supplemental saphenous vein grafts is presented. There were 725 coronary grafts performed (3.2 per patient). Forty-four IMA grafts were sequential. In 42 patients, the right IMA was placed through the transverse sinus to revascularize the circumflex artery. Operative mortality was 4% (9 of 227 patients). Postoperative complications included sternal infection (4 patients), reexploration for bleeding (5), and diaphragmatic dysfunction (10). Postoperative arteriography in 30 patients (mean interval, 4 1/4 years) revealed that 92% (34/37) of the left IMA and 87% (26/30) of the right IMA grafts were patent. Late follow-up was complete in 207 surviving patients. Eighteen late deaths (9 cardiac and 9 noncardiac) occurred. Actuarial survival was 83% at 10 years after operation. Of 68 patients followed from 8 to 12 1/2 years (mean interval, 10 1/2 years), 69% were asymptomatic, and 28% were in New York Heart Association Functional Class II. We conclude that bilateral IMA grafting can be accomplished with low operative risk and provides excellent long-term results.     

Comparison of long-term clinical results of double versus single internal mammary artery bypass grafting

BACKGROUND: The long-term benefits of double versus single internal mammary artery (IMA) coronary bypass grafting have not yet been established. METHODS: Six hundred patients were studied retrospectively 10 years after coronary revascularization using saphenous vein grafts (SVGs) only or single or double IMA grafts. RESULTS: Patients with double IMA grafts were younger and were more likely to have diabetes, left main coronary stenosis, and three-vessel coronary artery disease than patients with SVGs or single IMA grafts. Patients with SVGs and double IMA grafts had a greater number of diseased coronary vessels and a greater number of coronary bypass grafts per patient than patients with single IMA grafts (mean +/- SEM, 2.8 +/- 1.0, 2.8 +/- 0.7, 2.1 +/- 0.8 grafts per patient, respectively, p < 0.0001). Actuarial survival rates 10 years after placement of SVGs and single and double IMA grafts averaged 83% +/- 6%, 90% +/- 4%, and 87% +/- 8%, respectively (p = 0.03). Cox regression analysis showed that diabetes (relative risk, 2.03; 95% confidence interval, 1.55 to 2.66) and chronic pulmonary obstructive disease (relative risk, 2.20; 95% confidence interval, 1.58 to 3.80) increased, whereas an IMA graft on the left anterior descending coronary artery significantly decreased, the risk of death after operation (relative risk, 0.45; 95% confidence interval, 0.36 to 0.57) throughout the follow-up period. CONCLUSIONS: Use of an IMA graft on the left anterior descending coronary artery improves survival compared with use of an SVG. Although patients with double IMA grafts had a greater number of poor prognosis risk factors before operation, their 10-year survival rate was similar to that of patients with a single IMA graft.     

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.     

Bilateral Internal Mammary Artery Grafts in Patients with Left Main Coronary Artery Disease

The use of the internal mammary artery (IMA) in myocardial revascularization has been expanded with bilateral and sequential grafting. However, its application in the presence of left main coronary artery stenosis (LMCAS) has not been well established. From September 1983 through December 1990, 280 patients with LMCAS greater than 50% were revascularized (3.4 mean grafts per patient) with bilateral IMA and saphenous vein grafts. Eighty-one were sequential IMA grafts. There were 234 males (83.6%) and 46 females (16.4%) with a mean age of 64.4 years (range 39 to 84 years). Preoperatively, there were six patients (2.1%) in New York Heart Association (NYHA) Class I, 30 patients (10.7%) in Class II, 130 patients (46.4%) in Class III, and 114 patients (40.7%) in Class IV. Fifty-six patients (20.0%) had an ejection fraction less than 50%. In-traaortic balloon counterpulsation was used preoperatively in 26 patients (9.3%) and intraoperatively in 11 patients (3.9%). There were four hospital deaths (1.4%). Hospital complications included: reoperation for bleeding, 7 patients (2.5%); pulmonary insufficiency, 21 patients (7.5%); perioperative infarction, 14 patients (5.0%); and stroke, 4 patients (1.4%). Follow-up was obtained in 276 hospital survivors (100.0%) with a mean of 33.4 months. There were 20 late deaths (7.1%): seven cardiac related and 12 noncardiac related. Postoperative assessment reveals substantial functional improvement. These results furnish evidence that bilateral IMA grafts can be accomplished with a low operative risk and can provide excellent functional results in patients with LMCAS.     

Different responses of coronary artery and internal mammary artery bypass grafts to ergonovine and nitroglycerin in variant angina

The dynamic responses of a coronary artery and an internal mammary artery (IMA) graft to pharmacological intervention were examined by arteriography in 5 patients with variant angina who had undergone coronary artery bypass grafting with an in situ IMA to the left anterior descending coronary artery. Preoperative electrocardiographic findings included elevated ST segments in chest leads during attacks of angina, and all patients had severe fixed lesions in addition to marked spasm of the left anterior descending coronary artery after the administration of ergonovine maleate. Postoperatively with ergonovine stimulation, complete occlusion or marked subtotal narrowing was again observed at the primary fixed lesion in the proximal portion of the left anterior descending coronary artery, but the IMA graft and the coronary artery distal to the anastomotic site maintained satisfactory patency with no further occurrence of anginal pain or ST segment elevation. By computer-assisted graphic analysis, which allows highly reproducible measurements of vascular internal diameters, the diameter of the IMA showed only small changes under ergonovine (p = not significant) or nitroglycerin (p less than 0.05) stimulation in contrast to the marked vascular reactivity of the coronary artery (p less than 0.05 and less than 0.01, respectively). These findings indicate that the IMA graft is unresponsive to ergonovine at least in the amount required to produce coronary artery spasm in patients with variant angina and fixed lesions. The IMA graft appears to function well from a clinical and pharmacological viewpoint in patients with variant angina.     

A case report of bilateral free internal mammary artery bypass grafting reoperation--spontaneous resolution of stenotic LAD graft one year after revascularization

We experienced a coronary artery bypass reoperation utilizing bilateral free internal mammary artery (IMA) grafts for a 68 year old male with unstable angina due to graft occlusion. Although post-operative early graftgraphy showed LAD graft stenosis, it resolved completely at the second graftgraphy one year after the operation. Recently in situ IMA grafting has become a standard method for coronary artery revascularization because of its long term high patency rate. On the other hand, free IMA grafting has been rarely tried in our country. Though there has been a few reports of the growth and enlargement of in situ IMA graft, similar events in free IMA graft are rare and not found in the literature. We feel our case of spontaneous resolution of free IMA graft stenosis is unique and worth reporting.     

Efficacy of the internal mammary artery in combined aortic valve replacement-coronary artery bypass grafting

BACKGROUND: While internal mammary artery (IMA) use predicts improved survival after coronary bypass grafting (CABG), it remains unknown whether patients undergoing concomitant aortic valve replacement (AVR) realize a similar benefit. METHODS: All patients at a single teaching institution, undergoing combined AVR-CABG, which included a graft to the left anterior descending coronary artery (LAD) from 1984 to 1994 (n = 227) were examined retrospectively. RESULTS: Patients receiving an IMA graft (yesIMA, n = 135) and patients receiving only saphenous vein grafts (nonIMA, n = 92) were not different in their presenting symptoms, or in their incidence of preoperative risk factors. The patients with IMA were more likely to be male, have a later year of operation, be younger, and have a greater body surface. Morbidity was not different between groups. IMA use did not affect 30-day mortality. Long-term actuarial survival was greater in the group with IMA (63% +/- 7% vs 42% +/- 6% at 5 years, p < 0.01). A multivariate Cox proportional hazards model demonstrated that use of an IMA graft improved survival, while recent myocardial infarction, diabetes, earlier year of operation, and lower ejection fraction diminished long-term survival. The relative risk of IMA grafting was 0.570. CONCLUSIONS: Within the limits of a retrospective analysis, patients in a modern era of cardiac operation, who undergo combined AVR-CABG, do not suffer increased morbidity from IMA use, and may realize a survival benefit from use of the IMA as a conduit for bypass of the LAD coronary artery.     

Extended use of bilateral internal thoracic arteries for coronary artery bypass grafting in the elderly

Objective: Internal thoracic artery (ITA) grafts provide better early and long-term patency than saphenous vein (SV) grafts. Furthermore, bilateral ITA grafting has recently demonstrated better long-term results than unilateral ITA grafting. However, its use in the elderly is controversial. Methods: From March 1991 through November 2001, 307 consecutive patients aged 65 years or over undergoing isolated coronary artery bypass grafting (CABG) were reviewed, and the influence of bilateral ITA grafting on the early and long-term results was evaluated. All ITA grafts were harvested as a pedicle, and almost all of which were used as in-situ grafts. Results: Operative mortality in 138 patients undergoing bilateral ITA grafting was 1.4%, and in 108 patients undergoing unilateral ITA grafting, the rate was 0.9%. Predischarge angiography conducted in 97% of the subjects showed that the patency rate of all the ITA grafts (98.9%) was superior (p<0.0001) to that of all the SV grafts (93.6%). In comparisons of survival and freedom from cardiac events at 10 years after CABG, the bilateral use of ITA grafts was proved to be more beneficial than the unilateral use (p<0.05). Conclusions: It was demonstrated that bilateral ITA grafting could be performed with acceptable mortality and morbidity. Moreover, it offers better long-term survival and freedom from cardiac events than either unilateral ITA grafting or no ITA grafting. Bilateral ITA grafting thus can serve as a favorable procedure even in elderly patients.     

Prospective study of feasibility of routine use of multiple internal mammary artery anastomoses

A study of 100 consecutive patients requiring multiple coronary artery bypasses was undertaken to evaluate the feasibility of routine use of multiple internal mammary artery (IMA) anastomoses. In 99 patients the IMA was used and in 80 patients bilateral IMA bypasses were done. In 15 patients multiple anastomoses with a single IMA precluded the need for bilateral IMA bypasses. In only 4 patients were bilateral IMA left to be contraindicated. By combination of use of both IMAs, free grafts and sequential grafts, the IMA accounted for 70% of the 318 anastomoses in these 100 patients. Scrupulous attention to technique and the use of the operating microscope are necessary to achieve multiple IMA anastomoses. It was concluded that the IMA can be used to supply the majority of anastomoses needed for coronary artery revascularization in nearly all patients.     

Clinical results of sequential and "Y" grafting with the internal mammary artery

One hundred and sixty-five patients (125 men, 40 women; age ranged from 40 to 81 years), underwent coronary artery bypass grafting in the 3 years period from 1986 to 1988. The internal mammary artery (IMA) was applied to 125 patients (75.8%). The sequential left IMA grafting to the left anterior descending coronary artery (LAD) and the diagonal branch (Dg) was performed in 9 out of 125 patients. In 3 of 9 patients, the right IMA was simultaneously grafted to the obtuse marginal branch (OM). In situ bilateral IMAs grafting to the LAD and Dg or LAD and OM were used in 13 patients. In three patients, "Y" grafting (the free right IMA was anastomosed to the side of the in situ left IMA) was performed for LAD and Dg. Eighty-one of 82 IMA grafts (99%) were patent about 1 month after operation. Three patients (1.8%) died during hospitalization, one from Low Output Syndrome, two from cerebral infarction. Perioperative complication included myocardial infarction in 5 (3.0%), cerebral infarction in 10 (6.0%). We concluded that the IMA could be applied in multivessel grafting as well as single vessel grafting in severe diffuse coronary artery disease in the Japanese, and the early patency was good even in the sequential and "Y" grafting.     

Results of internal thoracic artery grafting over 15 years: single versus double grafts

One hundred consecutive patients who had coronary artery bypass grafting using both internal thoracic arteries (ITAs) and saphenous veins, operated on during a 3-year period between 1972 and 1975, have been compared retrospectively with a series of 100 patients operated on during the same period who had one ITA graft along with saphenous vein grafts. The two groups were similar with respect to age, sex, risk factors for coronary artery disease, angina class, extent of coronary artery disease, left ventricular function, number of coronary bypass grafts performed, and completeness of revascularization. Single ITA operative mortality was 2% and double ITA, 9% (p = NS). The mean follow-up of hospital survivors was 14.4 +/- 2.7 years; all but 7 patients had follow-up for at least 10 years. At 13 years, the actuarial patency of the right ITA was 85% and the left ITA, 82%. These data strongly suggest a survival benefit for patients with double ITA grafts among hospital survivors (74% versus 59%; p = 0.05). Patients receiving two ITA grafts had a significant freedom from subsequent myocardial infarction (75% versus 59%, p less than 0.025), recurrent angina pectoris (36% versus 27%, p less than 0.025), and subsequent total ischemic events (32% versus 18%, p less than 0.01). These data also suggest improved freedom from coronary artery interventional therapy (percutaneous transluminal coronary angioplasty and reoperation) when two ITA grafts were used. These results support the use of bilateral internal thoracic artery grafting in selected patients.