Comparison of internal mammary artery and saphenous vein bypass grafts for myocardial revascularization: exercise test and angiographic correlations.

The effectiveness of myocardial perfusion with internal mammary artery (IMA) bypass revascularization has been questioned. We compared 37 patients with single patent IMA bypass grafts with 26 patients who had single patent saphenous vein graft (SVG) bypass. Serial computer assisted graded maximal stress testing was used for quantitation of palliation. Patients were classified and compared according to the completeness of revascularization by postoperative catheterization. All patient subgroups, had statistically significant improvements in work capacity, maximal heart rate, maximal rate-pressure products, abnormal exercise electrocardiograms, and exercise-induced angina pectoris. The quantitative improvements in these measurements of patient palliation were the same during postoperative stress tests after either SVG or IMA revascularization. Considering the overall higher patency rate of the IMA bypass, the data indicate that this procedure, when surgically applicable, is preferable to SVG bypass.