Coronary Artery Bypass Grafting (CABG)

Through the 1950s and early 1960s, surgeons trying to treat obstructive coronary artery disease worked largely at the margins. The Vineberg procedure, which involved implanting the internal mammary artery directly into the myocardium, produced angiographic evidence of new collateral vessels in some patients but inconsistent clinical benefit. Endarterectomy of severely diseased coronary segments was technically demanding and had limited applicability. What the field lacked was a direct, reproducible means of restoring perfusion downstream from a critical stenosis.

René Favaloro, an Argentine surgeon who had joined the Cleveland Clinic in 1962, began working on the problem in the catheterization laboratory and the operating room alongside Mason Sones, whose technique of selective coronary angiography had made it possible for the first time to map the anatomy of coronary disease precisely. Sones's angiograms showed exactly where occlusions sat; Favaloro reasoned that a segment of autologous saphenous vein, sewn from the ascending aorta to a coronary artery distal to the blockage, could restore flow as directly as any plumbing repair. His initial series appeared in Annals of Thoracic Surgery in 1968.

The early results were striking. Patients with refractory angina, some of whom had been disabled by exertional chest pain, obtained relief that no medical regimen had produced. Favaloro's operative mortality in the initial series fell below 5 percent by 1970, a figure low enough to make the risk-benefit calculation favorable in patients with advanced, symptomatic disease. The technique was reproducible, teachable, and scalable, and within a few years cardiac surgery programs across the United States and Europe were training surgeons to perform it.

Large randomized trials followed over the next decade. The Veterans Administration Cooperative Study began publishing results in 1977, and the Coronary Artery Surgery Study (CASS) followed in the early 1980s, both comparing bypass surgery to medical therapy in defined patient populations. Those trials found that patients with left main disease, three-vessel disease with reduced ventricular function, and certain two-vessel anatomies lived longer after surgery. Other subgroups gained angina relief from bypass but no survival advantage. Those distinctions shaped the referral criteria that cardiologists and surgeons still apply.

Internal mammary artery grafts gradually supplanted saphenous vein as the preferred conduit after studies showed substantially better long-term patency, with the left internal mammary to the left anterior descending artery becoming the standard anchor of most bypass procedures. CABG became one of the most performed cardiac operations in the world. Favaloro returned to Argentina in 1971 to build a cardiac surgery program in Buenos Aires, where he worked until his death in 2000.