The Medicine, Angioplasty, or Surgery Study (MASS-II): a Randomized, Controlled Clinical Trial of Three Therapeutic Strategies for Multivessel Coronary Artery Disease: One-year Results

Objectives: We sought to evaluate the relative efficacies of three possible therapeutic strategies for patients with multivessel coronary artery disease (CAD), stable angina, and preserved ventricular function.

Background: Despite routine use of coronary artery bypass graft surgery (CABG) and percutaneous coronary intervention (PCI), there is no conclusive evidence that either one is superior to medical therapy (MT) alone for the treatment of multivessel CAD.

Methods: The primary end point was defined as cardiac mortality, Q-wave myocardial infarction (MI), or refractory angina requiring revascularization. All data were analyzed according to the intention-to-treat principle.

Results: A total of 611 patients were randomly assigned to either a CABG (n = 203), PCI (n = 205), or MT (n = 203) group. The one-year survival rates were 96.0% for CABG, 95.6% for PCI, and 98.5% for MT. The rates for one-year survival free of Q-wave MI were 98% for CABG, 92% for PCI, and 97% for MT. After one-year follow-up, 8.3% of MT patients and 13.3% of PCI patients underwent to additional interventions, compared with only 0.5% of CABG patients. At one-year follow-up, 88% of the patients in the CABG group, 79% in the PCI group, and 46% in the MT group were free of angina (p < 0.0001).

Conclusions: Medical therapy for multivessel CAD was associated with a lower incidence of short-term events and a reduced need for additional revascularization, compared with PCI. In addition, CABG was superior to MT for eliminating anginal symptoms. All three therapeutic regimens yielded relatively low rates of cardiac-related deaths.