Prognostic Value of Plasma Big Endothelin-1 Level among Patients with Three-Vessel Disease: A Cohort Study

Aim: To evaluate the prognostic value of plasma big endothelin-1 level in the context of three-vessel disease (TVD) with heavy atherosclerotic burden. Methods: A total of 6,150 patients with TVD and available big endothelin-1 data were included in the study. Participants were divided into two groups according to the optimal cutoff value of big endothelin-1 for mortality prediction. The primary endpoint was all-cause death. C-index, net reclassification improvement (NRI), and integrated discrimination improvement (IDI) were calculated to evaluate the added prognostic value of plasma big endothelin-1 level beyond the SYNTAX score II. Results: On the basis of the optimal cutoff value of 0.79 pmol/L, 1,984 patients were assigned to the high big endothelin-1 group. During a median follow-up of 6.8 years, 818 patients experienced all-cause death. Plasma big endothelin-1 level was significantly higher in patients who died than in patients who survived. Multivariable analysis found that high big endothelin-1 level was independently associated with an increased risk of mortality (hazard ratio: 1.36, 95% confidence interval: 1.18–1.57, P < 0.001). The association of big endothelin-1 with all-cause death was relatively consistent across subgroups with no significant interactions. The predictive ability of the SYNTAX score II was significantly enhanced by addition of plasma big endothelin-1 level (C-index: 0.723 vs. 0.715, P = 0.029; NRI: 0.304, P < 0.001; IDI: 0.009, P < 0.001). Conclusions: Plasma big endothelin-1 level is an independent predictor of long-term mortality in patients with TVD. It can improve the discrimination and reclassification of the SYNTAX score II for mortality prediction.