Impact of Diabetes on 10-Year Outcomes of Patients With Multivessel Coronary Artery Disease in the Medicine, Angioplasty, or Surgery Study II (MASS II) Trial

Eduardo Gomes Lima, MD; Whady Hueb, MD, PhD; Rosa Maria Rahmi Garcia,MD, PhD; Alexandre Costa Pereira,MD, PhD; Paulo Rogério Soares, MD, PhD; Desiderio Favarato, MD, PhD; Cibele Larrosa Garzillo, MD, PhD; Ricardo D'Oliveira Vieira, MD; Paulo Cury Rezende, MD; Myrthes Takiuti, RN, PhD; Priscyla Girardi, RN, PhD; Alexandre Ciappina Hueb, MD, PhD; José A. F. Ramires, MD, PhD; Roberto Kalil Filho,MD, PhD

Disclosures

Am Heart J. 2013;166(2):250-257. 

In This Article

Methods

The study design of MASS II has been previously published.[14] Briefly, MASS II is a randomized, prospective, single-center study that compared 3 therapeutic strategies, medical treatment without revascularization (MT), surgery (CABG), and angioplasty (PCI) in patients with multivessel and stable coronary artery disease. We defined as multivessel coronary disease patients with stenosis >70% in at least 2 major coronary arteries (left descending artery, left circumflex artery, or right coronary artery) or their major branches. A total of 611 patients were randomized between May 1995 and March 2000. The present report is a post hoc analysis using the overall MASS II population, which was retrospectively divided into 2 groups according to the presence of diabetes at baseline. Baseline, procedural, and follow-up data were stored in a dedicated electronic database specifically built for the MASS II study.

Diabetes was defined as the presence of serum glucose concentration ≥126 mg/dL on at least 2 separate occasions. We also considered as diabetic those patients with a previous diagnosis using specific medication, oral drugs, or insulin. These criteria were the most accepted definition for diabetes by the most recent specific guidelines.[15]

This protocol was approved by the hospital ethics committee and is in accordance with the Declaration of Helsinki. Written, informed consent was obtained from every patient.

Treatment Protocol

Device choice was left to the discretion of the physician and included BMS and balloon angioplasty. Excimer laser, directional atherectomy, and rotablator were available if necessary. The interventional cardiologist was encouraged to treat all arteries that were likely to contribute to ischemia and/or had lesions with >70% diameter stenosis. Angioplasty was performed according to a standard protocol that included administration of aspirin before the procedure. Dilatation of a stenotic vessel was considered successful if the residual stenosis of the lumen diameter was <50%. Patients treated with coronary stents were maintained on ticlopidine 250 mg twice daily for 1 month in addition to lifelong aspirin.

For patients assigned to the surgery, the cardiac surgeon was encouraged to intervene in all feasible stenosed arteries as an attempt to accomplish complete revascularization. Use of internal mammary conduits was strongly advised for all cases. Coronary bypass was executed using standard surgical techniques, under hypothermic arrest, with the use of blood cardioplegia. The medication recommendations were not different for patients randomized to surgery, angioplasty, or medical therapy alone. Medical treatment was performed to keep the patient free of angina. In addition, an attempt was made to reach goals regarding blood pressure, lipid, and glucose levels as recommended by specific guidelines over time.

Study Endpoints

The primary end point was to compare the impact of the 3 treatment strategies, medical, angioplasty, or surgery on the mortality rates (overall and cardiac mortality) in diabetic and non-diabetic patients in a 10-year follow-up.

Statistical Analysis

All data were analyzed according to intention-to-treat principle. Death rates were estimated by the Kaplan-Meier method, and differences among groups were assessed by means of the log-rank test. Mean levels of continuous variables were compared by 1-way analysis of variance (ANOVA), followed by the Tukey multiple-comparisons test. The Pearson χ2 test was used to compare qualitative variables in the 2 groups. The Fisher exact test was used for categorical variables. The Wilcoxon scores were used for categorical variables with an ordinal scale. Discrete variables were expressed as counts and percentages and composed in terms of relative risks with 95% confidence intervals. Tests were 2-tailed, and values of P < .05 were considered statistically significant. All statistical analyses were performed with the statistical package SPSS 17.0 (SPSS Inc, Chicago, IL).

The authors had full access to the data and take full responsibility for their integrity. All authors have read and agree to the manuscript as written.

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