NEW STUDY

Results

Besides long-term mortality, the biomarker score had an excellent performance in predicting one-year mortality and hospitalization due to heart failure. Biomarkers were assessed in a cohort of 478 patients undergoing elective cardiac surgery. After a median follow-up of 4.2 years, a total of 72 (15.1%) patients died. SuPAR, NT-proBNP and age were independent prognosticators of mortality in a multivariable Cox regression model after adjustment for EuroScoreII. We then calculated a simplified biomarker score comprising age, suPAR and NT-proBNP, which had a superior prognostic value compared to EuroScoreII (Harrel’s C of 0.76 vs. 0.72; P for difference = 0.02).

Association of suPAR and mortality

After median follow-up time of 4.2 years a total of 72 (15.1%) patients died including 51 (10.7%) patients who died due to CV events. Distribution of causes among CV mortality included sudden cardiac death (N = 3, 5.9%), heart failure (N = 16, 31,4%), atherosclerotic CV events (N = 24, 47.1%) and others/not further specified (N = 8, 15.7%). SuPAR showed a significant association with mortality with a hazard ratio (HR) per increase of one standard deviation (1-SD) of 1.96 (95% CI: 1.57–2.44; p < 0.001) and remained a significant predictor of mortality after adjustment for EuroScore II and NT-proBNP with an adjusted HR per 1-SD of 1.36 (95% CI: 1.04–1.79; p < 0.001). Mortality rates according to suPAR levels were 3.4% in patients with 0–2 ng/ml, 17.5% in patients with 2–3.99 ng/ml and 46.7% in patients with >4 ng/ml (p < 0.001).

Conclusion

The biomarker suPAR and NT-proBNP were strongly and independently associated with mortality in patients undergoing cardiac surgery. A simplified biomarker score comprising only three variables (age, suPAR and NT-proBNP) performed better than the established EuroScoreII with respect to intermediate and long-term outcome as well as hospitalization due to heart failure. As such, integration of established and upcoming biomarkers in clinical practice may provide improved decision support in cardiac surgery.

Methods

Study Cohort: Patients included in this single-centre prospective observational trial were scheduled for elective cardiac surgery including coronary artery bypass graft (CABG), valve surgery or a combination of both between May 2013 and August 2018 at the Department of Cardiac Surgery at the Medical Universityy of Vienna. The primary goal of the study was to investigate the occurrence of post-operative atrial fibrillation. Secondary goals included the assessment of prognostic factors including biomarkers during follow-up. Main inclusion criteria were age >18 years, absence of atrial fibrillation >6 months before surgery and absence of infection or chronic inflammatory conditions such as autoimmune disorders. The study protocol complies with the declaration of Helsinki. Patients were followed for a median follow-up time of 4.2 years.