George E. Green

Coronary Bypass Surgery with Internal-Thoracic-Artery Grafts — Effects on Survival over a 15-Year Period

BACKGROUNDnAortocoronary bypass surgery has been performed most often with the patients saphenous vein as the conduit. The internal-thoracic-artery graft, which has superior patency rates, has been shown to have clinical advantages, but it is not known how long these advantages persist.nnnMETHODSnWe identified all the patients in the registry of the Coronary Artery Surgery Study who had undergone first-time coronary-artery bypass grafting. Those with internal-thoracic-artery bypass grafts (749 patients) were compared with those with saphenous-vein bypass grafts only (4888 patients) with respect to survival over a 15-year follow-up period.nnnRESULTSnIn a multivariate analysis to account for differences between the two groups, the presence of an internal-thoracic-artery graft was an independent predictor of improved survival and was associated with a relative risk of dying of 0.73 (95 percent confidence interval, 0.64 to 0.83). This improved survival was also observed in subgroups including patients 65 years of age or older, both men and women, and patients with impaired ventricular function. The survival curves of the two groups showed further separation over the years of follow-up, with a more marked downsloping after eight years in the curve for the group with saphenous-vein grafts only than in that for the group with internal-thoracic-artery grafts.nnnCONCLUSIONSnAs compared with saphenous-vein coronary bypass grafts, internal-thoracic-artery grafts conferred a survival advantage throughout a 15-year follow-up period. The survival advantage increased with time, suggesting that the initial selection of the conduit was a more important factor in survival than problems appearing long after surgery, such as the progression of coronary disease.

Internal thoracic artery grafts: 20-year clinical follow-up

OBJECTIVESnThis study compared the long-term clinical results of coronary artery bypass surgery in patients with internal thoracic artery grafts with those in patients with vein grafts only.nnnBACKGROUNDnAortocoronary artery bypass surgery has been performed for > 25 years, primarily utilizing the saphenous vein and internal thoracic artery as conduits. Although the internal thoracic artery has been shown to confer a clinical advantage, it is not known for how many years this benefit will continue.nnnMETHODSnAll consecutive patients undergoing initial coronary artery bypass surgery between 1970 and 1973 were followed for up to 20 years. Clinical evaluation included survival, late myocardial infarction, need for reoperation and recurrence of angina. Patients were analyzed in three groups: vein grafts only (214 patients); a single internal thoracic artery graft with or without associated vein grafts (490 patients); and bilateral internal thoracic artery grafts (39 patients). Use of the operating microscope was also analyzed with regard to effect on survival.nnnRESULTSnThe internal thoracic artery graft and use of the operating microscope were independent predictors of mortality and reduced the risk of dying by a factor of 0.68 and 0.76, respectively. An internal thoracic artery graft resulted in a mean survival of 4.4 years longer than that with vein grafts alone. The internal thoracic artery graft compared with vein grafts was associated with fewer reoperations (p < 0.001), fewer late myocardial infarctions, lower associated mortality rates (p < 0.04) and less early recurrence of angina (p = 0.03).nnnCONCLUSIONSnThe internal thoracic artery graft and use of the operating microscope confer a superior clinical advantage over the saphenous vein graft throughout a 20-year follow-up period. The advantage of an internal thoracic artery graft does not decrease with time, suggesting that the choice of conduit at the initial operation is more important clinically than progression of coronary artery disease.

Internal Mammary Artery-to-Coronary Artery Anastomosis: Three-Year Experience with 165 Patients

Abstract From February, 1968, through June, 1971, internal mammary-to-coronary artery anastomosis was performed in 165 patients. Of these patients, 84 had single aorta-to-coronary artery saphenous vein grafts and 34 had double aorta-to-coronary artery saphenous vein grafts in addition to the internal mammary anastomoses. Follow-up data were completed in December of 1971. The hospital mortality was 7.1% overall and 4.4% in the largest and most recent group of patients operated upon. Postoperative angiography was performed in 70 patients from two weeks to three years following operation, most often several months following operation. At the time of reexamination, closure of 3% of internal mammary artery grafts and 30% of saphenous vein grafts had occurred. Nineteen percent of patients had recurrence of angina from two weeks to thirty months following operation. After discharge from the hospital, 1 patient sustained a myocardial infarction, but there were no fatal infarctions during 2,047 cumulative patient-months of follow-up.

Clinical implications of internal mammary artery bypass grafts: the Coronary Artery Surgery Study experience.

From the Coronary Artery Surgery Study Registry, all patients undergoing initial bypass surgery procedures with independent vein grafts were identified. The 950 patients receiving an internal mammary artery bypass graft were compared with the 6027 patients receiving vein graft alone. Improved survival rates with internal mammary artery grafts were noted at hospitals in which these grafts were performed infrequently as well as those in which the internal mammary artery graft was used frequently. The improved survival was noted in patients with normal (p = .004) as well as impaired (p = .004) ventricular function, in men (p = .0001) as well as women (p = .005), in patients over age 65 (p = .01) as well as younger patients (p less than .0001), and in those with (p = .05) or without (p less than .0001) critical stenosis of the left main coronary artery. The internal mammary artery bypass graft was an independent predictor of survival (p = .0004) and reduced the risk of dying by a factor of 0.64. It was concluded that the internal mammary artery graft is the bypass vessel of choice and should not be denied any subgroup.

Five-year follow-up of microsurgical multiple internal thoracic artery grafts

In a consecutive series of 143 patients requiring multiple coronary artery bypass grafts, 317 of 441 anastomoses (72%) were constructed from internal thoracic arteries. Of these 143 patients, 103 had bilateral, 51 sequential, and 49 free internal thoracic artery grafts. When compared with an earlier series of 494 patients who underwent only one internal thoracic artery anastomosis, the surgical morbidity and mortality were not increased, but, during 5 years of follow-up, the incidences of postoperative angina and myocardial infarction were found to decrease significantly--32.5% versus 10.5% (p < 0.001) and 5.7% versus 1.4% (p < 0.03), respectively. We conclude that, for patients with multivessel disease, multiple internal thoracic artery grafts confer better protection from the clinical manifestations of ischemic heart disease than does one internal thoracic artery graft. The use of high magnification (8 to 12x, surgical microscope) was essential to the success of this method.

Left Recurrent Laryngeal Nerve Injury Following Internal Mammary Artery Bypass

To our knowledge, recurrent laryngeal nerve injury has not been reported previously as a complication of internal mammary artery mobilization for coronary artery bypass. We recently experienced this complication and are presenting a case history of the problem and comments.

Use of the internal mammary artery in myocardial revascularization

Internal mammary artery-coronary artery anastomosis is currently considered the newest and best technique for surgical revascularization of ischemic myocardium. The origin and evolution of this technique are reviewed.

Left Heart Decompression by Closed Gravity Drainage

Abstract Decompression of the left ventricle by closed gravity drainage into the venous return reservoir was found to be an especially useful adjunct in coronary artery surgery. The preferred technique of transatrial cannulation of the left ventricle affords efficient left heart decompression during heart-lung bypass and is used for direct measurement of left heart pressure and, when indicated, for selective left heart bypass.