Methods
Patients undergoing cardiac surgery from 2004-2007 were enrolled in a prospective biomarker cohort in the Northern New England Cardiovascular Disease Study Group Registry. Preoperative, postoperative, and the change in serum biomarker levels were categorized by quartile. We used Kaplan-Meier survival analysis and Cox regression models adjusted for variables in the STS’s ASCERT long-term survival calculator to study the association of biomarker levels with long-term survival. Following Kaplan-Meier analysis, quartiles 2 and 3 were found to have similar survival and were therefore combined into one category.
Results
In our cohort (n=1,648), median follow-up time was 8.5 years (IQR: 7.6-9.7), during which there were 227 deaths. The 10-year survival rate was 86%. Kaplan-Meier survival analysis demonstrated a significant (p<0.001) difference across quartiles of each biomarker levels measurement. After adjustment, pre-operative, post-operative, and the change in biomarker levels in quartile 4 (highest serum levels/change) were significantly predictive of worse survival (hazard ratio range 1.77- 2.89, all p<0.05) compared to quartile 1; however, levels of sST-2 and NT-proBNP in quartiles 2-3 demonstrated a non-statistically significant trend with long-term survival.