Coronary Artery Bypass Graft Surgery Outcomes Following 6.5 Years: A Nested Case–control Study

Abstract

Background: Coronary artery disease (CAD) is the leading causes of mortality and morbidity in worldwide. This nested case–control study investigated the predictors of death in long‑term follow‑up after coronary artery bypass graft surgery (CABG).

Methods: Cases were defined as CABG patients who died in the period of May 2006–March 2013. Controls were CABG patients
who were alive in the same period. Cases and controls were derived from an existing cohort, Tehran Heart Center‑Coronary Outcome Measurement. One hundred and fifty‑nine patients in control group were randomly selected from 566 available patients in follow‑up database. A series of simple and multiple logistic regressions was performed in the context of univariate and multivariate analyses, respectively, for computing unadjusted and adjusted odds ratios and their confidence intervals (CI). In the univariate analyses, demographic or cardiometabolic factors were entered separately, and for multivariate analysis, we got both significant risk factors from univariate analysis and the major risk factors.

Results: The results of multivariate analyses showed that for age, the likelihood of mortality increases in CABG patients (95%CI: 1.1; 1.03–1.2; P < 0.005). Other significant independent risk factors were peripheral vascular disease (PVD) (95%CI: 2.7; 1.06–6.8; P = 0.036), diabetics (95%CI: 2.49; 0.9–6.3; P = 0.039), smoking (95%CI: 4.38; 1.45–13.7; P = 0.011), length of stay in hospital after CABG surgery (95%CI: 1.14; 1.0–1.24; P = 0.001), total cholesterol (95%CI: 1.12;
1–1.2; P = 0.001), and C‑reactive protein (CRP) (95%CI: 1.12; 0.99–1.27; P = 0.049) (all P < 0.05).

Conclusions: The study results indicated that age, diabetes, cigarette smoking, PVD, long length of stay in hospital, elevated triglycerides, total cholesterol, CRP, and high‑density lipoprotein
cholesterol were significant contributing to increased mortality after CABG. It seems that vulnerable older patients continue to be at high risk with poor outcomes.

Keywords: Cardiometabolic risk factors, coronary artery bypass graft surgery, mortality, outco