INTERNAL THORACIC ARTERY GRAFTS - 20-YEAR CLINICAL FOLLOW-UP

Objectives. This study compared the long-term clinical results of coro nary artery bypass surgery in patients with internal thoracic artery g rafts with those in patients with vein grafts only. Background. Aortoc oronary artery bypass surgery has been performed for >25 years, primar ily utilizing the saphenous vein and internal thoracic artery as condu its. Although the internal thoracic artery has been shown to confer a clinical advantage, it is not known for how many years this benefit mi ll continue. Methods. All consecutive patients undergoing initial coro nary artery bypass surgery between 1970 and 1973 were followed for up to 20 years, Clinical evaluation included survival, late myocardial in farction, need for reoperation and recurrence of angina. Patients were analyzed in three groups: vein grafts only (214 patients); a single i nternal thoracic artery graft with or without associated vein grafts ( 490 patients); and bilateral internal thoracic artery grafts (39 patie nts). Use of the operating microscope mas also analyzed with regard to effect on survival. Results. The internal thoracic artery graft and u se of the operating microscope were independent predictors of mortalit y and reduced the risk of dying by a factor of 0.68 and 0.76, respecti vely. An internal thoracic artery graft resulted in a mean survival of 4.4 years longer than that with vein grafts alone, The internal thora cic artery graft compared with vein grafts was associated with fewer r eoperations (p < 0.001), fewer late myocardial infarctions, lower asso ciated mortality rates (p < 0.04) and less early recurrence of angina (p = 0.03). Conclusions. The internal thoracic artery graft and use of the operating microscope confer a superior clinical advantage over th e saphenous vein graft throughout a 20-year follow-up period. The adva ntage of an internal thoracic artery graft does not decrease with time , suggesting that the choice of conduit at the initial operation is mo re important clinically than progression of coronary artery disease.