Peri-operative copeptin concentrations and their association with myocardial injury after vascular surgery A prospective observational cohort study

BACKGROUND Copeptin levels in conjunction with cardiac troponin may be used to rule out early myocardial infarction in patients presenting with chest pain. Raised pre-operative copeptin has been shown to be associated with postoperative cardiac events. However, very little is known about the peri-operative time course of copeptin or the feasibility of very early postoperative copeptin measurement to diagnose or rule-out myocardial injury. OBJECTIVES In this preparatory analysis for a larger trial, we sought to examine the time course of peri-operative copeptin and identify the time at which concentrations returned to pre-operative levels. Second, in an explorative analysis, we sought to examine the association of copeptin in general and at various time points with myocardial injury occurring within the first 48 h. DESIGN Preparatory analysis of a prospective, observational cohort study. SETTING Single university centre from February to July 2016. PATIENTS A total of 30 consecutive adults undergoing vascular surgery. INTERVENTION Serial peri-operative copeptin measurements. MAIN OUTCOME MEASURE We measured copeptin concentrations before and immediately after surgery (0 h), then at 2, 4, 6 and 8 h after surgery and on the first and second postoperative day. Postoperative concentrations were compared with pre-operative levels with a Wilcoxon signed-rank test. Second, we explored an association between postoperative copeptin concentrations and myocardial injury by the second postoperative day. Myocardial injury was defined as a 5 ng l(-1) increase between pre-operative and postoperative high-sensitivity cardiac troponin T with an absolute peak of at least 20 ng l(-1). RESULTS Immediate postoperative copeptin concentrations (median [interquartile range]) increased nearly eightfold from pre-operative values (8.5 [3.6 to 13.8] to 64.75 pmoll(-1) [29.6 to 258.7]; P < 0.001). Copeptin concentrations remained elevated until returning to baseline on the second postoperative day. Postoperative copeptin was significantly higher in patients experiencing myocardial injury than in those who did not (P = 0.02). The earliest most promising single time point for diagnosis may be immediately after surgery (0 h). The receiver-operating characteristics curve for immediate postoperative copeptin and myocardial injury by the second postoperative day was 0.743 (95% confidence interval 0.560 to 0.926). CONCLUSION Copeptin concentrations are greatly increased after vascular surgery and remain so until the 2nd postoperative day. Postoperative copeptin concentrations appear to be higher in patients who go on to exhibit myocardial injury. Immediate postoperative copeptin concentrations show promise for eliminating or identifying those at risk of myocardial injury.