Cardiac Biomarkers Predict Long-term Survival After Cardiac Surgery

Abstract

Background: Cardiac biomarkers soluble ST-2 (sST-2) and N-terminal prohormone B-type natriuretic peptide (NT-proBNP) may be associated with long-term survival after cardiac surgery. This study explored the relationship between long-term survival after cardiac surgery and serum biomarker levels.

Methods: Patients undergoing cardiac surgery from 2004 to 2007 were enrolled in a prospective biomarker cohort in the Northern New England Cardiovascular Disease Study Group Registry. Preoperative serum biomarker levels, postoperative serum biomarker levels, and the change in serum biomarker levels were categorized by quartile. The study used Kaplan-Meier survival analysis and Cox regression models adjusted for variables in the American College of Cardiology Foundation-Society of Thoracic Surgeons Collaboration on the Comparative Effectiveness of Revascularization Strategy (ASCERT) long-term survival calculator to study the association of biomarker levels with long-term survival. After Kaplan-Meier analysis, quartiles 2 and 3 were found to have similar survival and were therefore combined into 1 category.

Results: In the study cohort (n = 1648), median follow-up time was 8.5 years (interquartile range, 7.6-9.7 years), during which there were 227 deaths. The 10-year survival rate was 86%. Kaplan-Meier survival analysis demonstrated a significant (P < .001) difference across quartiles of each biomarker level measurement. After adjustment, preoperative levels, postoperative levels, and the change in biomarker levels in quartile 4 (highest serum levels or change) were significantly predictive of worse survival (hazard ratio range, 1.77-2.89; all P < .05) compared with quartile 1; however, levels of sST-2 and NT-proBNP in quartiles 2 and 3 demonstrated a nonstatistically significant trend with long-term survival.

Conclusions: Elevated preoperative and postoperative levels of sST-2 or NT-proBNP and large changes in these biomarkers' levels are associated with an increased risk of worse survival after cardiac surgery. These biomarkers can be used for risk stratification or assessing postsurgical prognosis.