The puzzle of positive results--myocardial revascularization.

T coronary-sinus reduction described by Verheye et al. in this issue of the Journal (pages 519–527) revives an old therapeutic concept. Between 1948 and 1968, Cleveland surgeon Claude Beck performed coronary-sinus ligation in more than 1000 patients, aiming to improve myocardial oxygenation. Despite Beck’s reports of impressive efficacy, few surgeons adopted his techniques. The history of this procedure and of other abandoned techniques of myocardial revascularization provides invaluable perspective on continuing efforts to treat coronary artery disease (CAD). As CAD’s prevalence increased in the early 20th century, physicians pursued it aggressively, using an astonishing range of surgical procedures. The common understanding of CAD as a mismatch between oxygen supply and demand suggested two basic strategies: increase blood flow to the heart or reduce demand for it. Some surgeons reduced myocardial oxygen demand by disrupting sympathetic innervation to the heart through sympathectomy or alcohol injection (1924, 1926, 1929; see box for historical references in the Journal). Others reduced metabolic activity with thyroidectomy (1933). Surgeons also tried to bring new blood to the heart by ligating the internal thoracic arteries to shunt blood through pericardiophrenic collaterals (1957a, 1959) or by implanting the internal thoracic arteries into the myocardium (1957b). Beck’s work was particularly innovative. Beginning in 1932, he created “extracoronary communications” by abrading the epicardium with a burr and by grafting pericardium, thoracic muscles, lung, diaphragm, stomach, spleen, omentum, or mediastinal fat onto its surface.1,2 Simply increasing supply was not enough. Beck believed that coronary occlusions created patchy myocardial ischemia. The juxtaposition of adequately and inadequately oxygenated tissue produced an electrical imbalance, “an irritable focus,” that triggered ventricular fibrillation1 — the heart, in effect, “electrocutes itself” (1960). To ensure an even distribution of blood, Beck elicited “intercoronary communications” by dusting the heart with irritants to create vascularized scar tissue.1 He tested powdered beef bone, iron filings, formaldehyde, horse serum, and dried, sterilized, human skin, but “powdered asbestos produced the most desirable result.” Other surgeons reengineered the heart’s venous drainage to improve myocardial oxygenation, inspired by the observation that angina often disappeared with right-sided heart failure.3 Had increased venous pressure somehow improved myocardial perfusion? Could the same effect be achieved by ligating the coronary sinus? In 1935, Louis Gross and colleagues in New York proposed that such ligation would dilate existing intracoronary collaterals. In experiments in animals, sinus ligation produced “a rapid increase in the extent of the coronary bed.”3 Partial ligation protected dogs against subsequent occlusion of their coronary arteries.2,3 The exact physiological mechanism was never clear. Beck speculated that venous congestion allowed the myocardium to extract more oxygen or minimized the oxygen differentials that produced fibrillating currents.4 World War II put Beck’s research on hold, but afterward he returned to myocardial revascularization and by 1955 had developed two distinct operations.2 One involved placing a bypass graft between the aorta and the coronary sinus, arterializing the vein, and then partially ligating the distal sinus. Despite good laboratory results, Beck abandoned this procedure because of unacceptable mortality (>25%) among patients. The other operation combined partial ligation of the coronary sinus with abrasion of the epicardium, application of asbestos powder, and grafting of mediastinal fat.4,5 This procedure provided a modest increase in blood flow and, more important, ensured more uniform perfusion, reducing the risk of “selfelectrocution.”4 Results were gratifying. Beck reported that 32% of 295 survivors studied were “completely or almost completely free of pain and have taken no medicaments since operation.” Another 62% had only occasional pain.4 Patients who’d been incapacitated before surgery resumed their previous jobs or engaged in “some kind of gainful work.” Eleven of 13 had significant improvement on ballistocardiography; 17 of 20 gained relief from “distressing and alarming” arrhythmias. Surgery im-