['To compare 2 different surgical approaches to treatment of patients with isolated predivisional stenosis of the left main coronary artery (IOSLM) and to evaluate the effect of chronic competitive flow from a patent arterial or venous graft to the circumflex system on the long-term patency of internal thoracic artery (ITA) to left anterior descending grafts.', 'Thirty-two patients with IOSLM were treated at our institutions during a 9-year period: 14 patients received double ITA grafts, whereas 18 underwent ITA graft plus saphenous vein (SV) bypass. All patients were reviewed clinically and angiographically at long-term follow-up.', 'No patient died during hospitalization. At a mean follow-up of 96±9 months 7 patients had died (6 from noncardiac causes) and 5 had experienced angina/ischemia recurrence, without differences between the 2 revascularization strategies. At control reangiography all ITA and SV grafts were found to be fully patent, without evidence of caliber reduction or string sign in the ITA.'] Does chronic competitive flow from a patent arterial or venous graft to the circumflex system impair the long-term patency of internal thoracic artery to left anterior descending grafts in patients with isolated predivisional left main disease : long-term angiographic results of 2 different revascularization strategies?