Five-year follow-up of the medicine, angioplasty, or surgery study (MASS) - A prospective, randomized trial of medical therapy, balloon angioplasty, or bypass surgery for single proximal left anterior descending coronary artery stenosis

Background-Although coronary angioplasty and myocardial bypass surgery are routinely used, there is no conclusive evidence that these interventional m ethods offer greater benefit than medical therapy alone. This study is inte nded to evaluate, in a prospective, randomized, and comparative analysis, t he benefit of the 3 current therapeutic strategies for patients with stable angina and single proximal left anterior descending coronary artery stenos is. Methods and Results-In a single institution, 214 patients with stable angin a, normal ventricular function, and severe proximal stenosis (>80%) on the left anterior descending artery were selected for the study. After random a ssignment, 70 patients were referred to surgical treatment, 72 to angioplas ty, and 72 to medical treatment. The primary end points were the occurrence of acute myocardial infarction or death and presence of refractory angina. After a 5-year follow-up, these combined events were reported in only 6 pa tients referred to surgery as compared with 29 patients treated with angiop lasty and 17 patients who only received medical treatment (P=0.001). Howeve r, no differences were noted in relation to the occurrence of cardiac-relat ed death in the 3 treatment groups (P=0.622). No patient assigned to surger y needed repeat operation, whereas 8 patients assigned to angioplasty and 8 patients assigned to medical treatment required surgical bypass after the initial random assignment. Surgery and angioplasty reduced anginal symptoms and stress-induced ischemia considerably. However, all 3 treatments effect ively improved limiting angina. Conclusions-Bypass surgery for single-vessel coronary artery disease is ass ociated with a lower incidence of medium-term and long-term events as well as fewer anginal symptoms than that found in the patients who underwent ang ioplasty or medical therapy. In this study, coronary angioplasty was only s uperior to medical strategies in relation to the anginal status. However, t he 3 treatment regimens yielded a similar incidence of acute myocardial inf arction and death. Such information should be useful when choosing the best therapeutic option for similar patients.