Coronary artery bypass grafting in octogenarians: a nomogram for predicting all-cause mortality

The benefits and risks of coronary artery bypass grafting (CABG) in octogenarians remain unclear. This study aimed to identify the predictors of increased risk of all-cause mortality in octogenarian patients after CABG.

We retrospectively analyzed the data of 1636 octogenarians who underwent isolated elective on-pump CABG between 2007 and 2016. The primary endpoint was mortality from any cause. The Kaplan-Meier curve was generated for mortality. A univariate Cox regression was performed for preprocedural and procedural variables. The Akaike information criterion (AIC) using the Cox proportional hazard model was applied to determine the strongest predictors. We designed a nomogram based on the selected variables to calculate the mortality risk after one, five, and ten years. The bootstrap resampling based on the C-index was performed to validate the final model. Calibration plots were created at different time points.

The mean age of the patients was 82.03 years (SD = 1.74), and 74% were male. In a median follow-up of 9.2 (95% CI 9.0,9.5) years, 626 (38.2%) patients died. After the selection of best predictors based on AIC, the multivariable Cox regression showed that ejection fraction < 40 (HR 1.41, 95% CI 1.21-1.65, P < 0.001), two-vessel disease (HR: 0.59, 95% CI 0.40-0.89, P = 0.012), peripheral vascular disease (HR 1.52, 95% CI 1.05-2.21, P = 0.027), and valvular heart disease (HR 1.45, 95% CI 1.24-1.69, P < 0.001) were the significant predictors of all-cause mortality.

Octogenarians who undergo CABG have a high mortality risk, influenced by several preprocedural and procedural risk factors. The proposed nomogram can be considered for optimizing the management of this vulnerable age group. Clinical registration number IR.TUMS.THC.REC.1400.081.