Free internal mammary artery graft in myocardial revascularization

Between August 1986 and March 1993, 124 patients (102 men; mean age of 59 years) underwent myocardial revascularization with the use of at least one free internal mammary artery (FIMA). This group represents 4.5% of the 2725 coronary bypasses performed during the same period. Seventy-six patients (61%) had suffered from at least one previous myocardial infarction. Forty-five patients (36%) had unstable angina; three-vessel disease was found in 100 cases (80.5%) and a left ventricular ejection fraction lower than 0.4 in 22 (17.7%). There were 18 (14.5%) redo procedures and 90 (72.5%) bilateral internal mammary artery (IMA) grafts. The reasons for using a FIMA were: too short an internal mammary artery pedicle in 83 patients, IMA injury at harvesting in 30 patients and post-bypass ischaemia in areas grafted with pedicled IMA (PIMA) in 11 patients. Cardiopulmonary bypass, moderate hypothermia (30 °C) and crystalloid anterograde and retrograde cardioplegia were used in all cases. Sixty-seven FIMA grafts were anastomosed directly to the ascending aorta; 57 were sutured via a saphenous hood using a running suture of polypropylene 7/0 and three were anastomosed end-to-end to a PIMA graft. FIMA grafts were directed to the left anterior descending (34%), the circumflex (37%) and the right coronary artery (29%). In total, 179 anastomoses were constructed using 127 FIMA, 136 using PIMA and 158 using saphenous veins (3.8 anastomoses per patient). Hospital mortality and postoperative myocardial infarction rates were 5.6% (seven patients) and 3.2% (four patients), respectively. Cardiac-related mortality was 3.2% (four patients); three of these four patients had been operated on for evolving infarction and one underwent a redo procedure. Four of the 117 survivors died later on; in two, it was cardiac-related and a result of global heart failure at 9 and 12 months. Of the 113 remaining patients, 106 are symptom free after a mean follow-up of 28.2 (range 3–84) months. Fifty-nine patients (50.4%) were restudied by angiography at a mean interval of 15 months. Patency rates of FIMA anastomosed either directly to the aorta or via a saphenous hood were 82.8 or 89.7%, respectively. Patency rates of FIMA directed to the left anterior descending, the circumflex and the right coronary artery were 85.7, 88 and 83.3%, respectively. Global FIMA patency was 86.4%, while global PIMA patency was 100%. The FIMA mid-term patency rates compare unfavourably with those of PIMA: FIMA should therefore be restricted to the cases where PIMA or other pedicled arterial grafts are unavailable.     

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.     

Pulmonary complications following myocardial revascularization with the internal mammary artery graft

A total of 106 patients participated in a clinical investigation to determine the incidence and etiology of pulmonary complications following myocardial revascularization with the internal mammary artery graft; 39 patients (group I), undergoing valve replacement or myocardial revascularization with vein grafts, served as control. The mammary artery was used for revascularization in the remaining patients. The pleura was opened during the dissection of the mammary graft in 34 patients (group II), but was left intact during harvesting of the internal mammary artery in 33 patients (group III). Inspiration and expiration chest X-rays were obtained during the first 3 months of convalescence to determine the presence of pleural fluid, the position of the left hemidiaphragm, and to asses diaphragmatic movement. Pleural effusions, left lower-lobe atelectasis, and elevation of the left hemidiaphragm were observed in all groups after operation, but were more commonly observed in those patients undergoing revascularization with the mammary artery graft. Postoperative chest X-rays just prior to discharge from hospital were normal in 69% of the control group, only 9% of patients in group II who had pleurotomy during mammary artery dissection, and 42% of group III. By 3 months, however, 95% of patients in groups I and II had normal chest X-rays, whereas 53% of patients in group II had persistent loss of left-lung volume related to the presence of left-lower-lobe atelectasis, left pleural effusions and organization of the postoperative hemothorax.(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.     

Late spontaneous revascularization of an internal mammary graft onto the anterior interventricular artery

The authors report a case of internal mammary artery graft anastomosed to the left anterior descending coronary artery (LADC) which was found to be non functional in the early post-operative period (one month) but second catheterization at one year revealed the graft to be patent with thrombosis of the LADC. This case shows the flow adjustment possibilities of internal mammary artery graft.     

Reoperation for myocardial revascularization using the internal mammary artery

From October 1984 up to February 1989, 40 patients had "redo" myocardial revascularizations using one or both internal mammary arteries (IMA) in over 1000 cases operated upon in our Department for coronary bypass grafts. Thirty-one patients had a further operation for unstable angina difficult to control with drugs. Mean interval of recurrence of angina after previous surgery was 48.5 months for all the cases, but the mean interval before the second bypass operation was 68 months. Severe disease of previous vein grafts was the reason for surgery in 25 patients and progressive atherosclerosis in native coronary arteries in 15 patients. Twenty-one patients had a single mammary artery; both mammary arteries were used in 19. Two cases had endarterectomy on left anterior descending (LAD). Four patients had peroperative acute myocardial infarction (AMI), 3 a low cardiac output syndrome, postoperative bleeding occurred in 3 cases and wound infection in one case. An intraaortic balloon pump was used preoperatively in one case and coming off bypass in two others. One patient died on the second day postoperatively from cardiac arrest following bilateral pneumothorax. There were no late deaths. At a mean follow-up of 20.5 months, 28 patients are free of symptoms but 11 are complaining of angina, 5 during exercise and 6 at rest. An exercise test was positive in 8 patients.     

Endothelial cell-seeded bovine internal mammary artery for complete revascularization

We present a 79-year-old woman with coronary heart disease who underwent complete revascularization by using a No-React bovine internal mammary artery seeded with autologous endothelial cells. Her postoperative course was uneventful, and the patient was recently in New York Heart Association functional class I. Multislice computed tomography imaging showed patent grafts at 20 months of follow-up.     

Long-term left internal mammary artery graft patency for coronary artery disease associated with pseudoxanthoma elasticum

Pseudoxanthoma elasticum (PXE) is a rare, inherited connective tissue disorder with numerous systemic manifestations that include premature coronary artery disease. Coronary artery bypass grafting (CABG) is known to be beneficial in patients with PXE-related coronary artery disease. In these patients, however, the suitability of arterial conduits, including the internal mammary artery, has been controversial. We present a patient with PXE-related coronary artery disease who has had long-term patency of a left internal mammary artery (LIMA) graft after an off-pump CABG procedure in which LIMA and bilateral radial artery conduits were used.     

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.     

Free internal mammary artery for coronary bypass

We studied 12 cases of free internal mammary artery (IMA) grafting. We used IMAs as free grafts mainly because of its shortness (6 cases 50%) and injury during dissection (4 cases 33%) and found the varicose change of saphenous vein in 5 cases (42%). Most of the grafting sites are distal parts of coronary arteries. Proximal anastomosis sites are other vein grafts (3 cases), other IMA grafts (3 cases), vein grafts interposing to the aorta (3 cases), and aorta (1 case). Patency rate of the free IMA grafts 4 weeks after operations was good (82%). Free IMA grafting is safe alternative to in situ IMA grafting when IMA grafts are short or injured and saphenous vein grafting is impossible.     

Bilateral internal thoracic artery T grafting for coronary artery revascularization

OBJECTIVES: We studied the early outcome of bilateral internal thoracic artery T grafting. METHODS: Coronary artery bypass grafting was studied retrospectively using bilateral internal thoracic artery T grafting in 51 patients. The T graft was made by anastomosing the free right internal thoracic artery to the in-situ left internal thoracic artery. Average patient age was 63.5 +/- 9.9 years, and the average number of anastomoses per patient was 3.6 +/- 0.9. In 35 patients, the right gastroepiploic artery (21 anastomoses in 20 patients), radial artery (1 anastomosis), free left internal thoracic artery (1 anastomosis) and saphenous vein graft (14 anastomoses in 13 patients) were used as additional bypass conduits. RESULTS: Hospital mortality was 0%. The morbidity of stroke was 1.9% (1 patient) and deep sternal infection 0%. Patency of the in-situ left internal thoracic artery was 49/50 anastomoses (98%) and that of the free right internal thoracic artery 81/84 anastomoses (96.4%). Mid-term coronary angiography in 7 patients demonstrated patent anastomosis of the T graft. Acute myocardial infarction unrelated to graft failure occurred in 2 patients during follow-up. Other patients were evaluated by exercise stress tests every year and none exhibited myocardial ischemia in the areas of T graft coronary revascularization. Three-year actuarial survival rate was 100% and freedom from cardiac events 96%. CONCLUSIONS: The bilateral internal thoracic artery T graft provides satisfactory early and mid-term outcomes in properly selected patients.     

The internal mammary bypass graft: a superior second coronary artery.

In a study of the initial 1,004 consecutive patients who had direct coronary artery bypass at Ochsner Medical Institutions, computer methods of data processing were used to compare the clinical results between patients who had saphenous vein (SV) grafts and those who had internal mammary artery (IMA) grafts. The factors compared were the long-term mortality rates, nonfatal myocardial infarction rates, relief or persistence of angina, and the percentage of patients who acquired congestive heart failure. A simple comparison showed the patients with IMA grafts did better in all four categories; however, in a subsequent analysis in which maldistributed factors were removed, the rates of anginal relief and congestive heart failure were not significantly improved. The major benefit appears to be an increase in longevity among patients who had IMA bypasses.     

Clinical experience of bovine internal mammary artery graft (BIOFLOW) for coronary artery bypass surgery

Bovine internal mammary artery graft (BIOFLOW: BIOVASCULAR INC. Netherlands) has been used for coronary artery bypass grafting (CABG) in 8 patients since May 1988 at Osaka Medical College Hospital. There were 4 males and 4 females. Mean age was 66.9 year-old ranged from 62 to 72. Two were emergency CABG and other six had inadequate saphenous veins. The internal mammary artery and/or the saphenous vein were concomitantly used in all patients. Number of grafts was 2 to 6 with the mean of 2.9 and BIOFLOW (phi 3 mm) was anastomosed to 2 left anterior descending arteries and 6 right coronary arteries, the mean graft flow of BIOFLOW was 72.5 ml/min ranged from 52 to 120 ml/min. One patient died of ventricular arrhythmia on 5 postoperative day. There was no new Q wave infarction. Postoperative angiogram within 2 months showed 4 of 5 BIOFLOW grafts were patent, and no stenosis was found in those patent grafts. All survivors returned to home with a freedom from angina. From our experience, although the number was small and the follow-up period was short, BIOFLOW can be expected as an conduit of choice for CABG when the saphenous vein was not available and the internal mammary artery and the gastroepiploic artery were not enough to accomplish the complete revascularization.