Helwani, Mohammad A.

Background The recent introduction of high‐sensitivity cardiac troponin (hs‐cTn) assays has allowed clinicians to measure hs‐cTn before and after cardiac stress testing, but the hs‐cTn release pattern and potential utility in identifying inducible myocardial ischemia are unclear. We thus conducted a systematic review and meta‐analysis to improve our understanding of hs‐cTn release associated with exercise and pharmacological stress testing. Methods and Results Studies published between January 2008 and July 2016 that reported hs‐cTn change values (high‐sensitivity cardiac troponin T [hs‐cTnT] or high‐sensitivity cardiac troponin I [hs‐cTnI]) in relation to cardiac stress testing were searched and reviewed by 2 independent screeners. Primary outcomes were pooled estimates of absolute and relative hs‐cTn changes after cardiac stress test, stratified by the presence of inducible myocardial ischemia. This meta‐analysis included 11 studies (n=2432 patients). After exercise stress testing, hs‐cTnT increased by 0.5 ng/L or 11% (6 studies, n=406) and hs‐cTnI by 2.4 ng/L or 41% (4 studies, n=365) in patients with inducible myocardial ischemia versus hs‐cTnT by 1.1 ng/L or 18% (8 studies, n=629; P =0.29) and hs‐cTnI by 1.8 ng/L or 72% (4 studies, n=831; P =0.61) in patients who did not develop inducible myocardial ischemia. After pharmacological stress test, hs‐cTnT changed by −0.1 ng/L or −0.4% (6 studies, n=251) and hs‐cTnI by 2.4 ng/L or 32% (2 studies, n=108) in patients with inducible myocardial ischemia versus hs‐cTnT by 0.7 ng/L or 11% (5 studies, n=443, P =0.44) and hs‐cTnI by 1.7 ng/L or 38% (2 studies, n=116; P =0.62) in patients who did not develop inducible myocardial ischemia. Conclusions hs‐cTn rising patterns after exercise and pharmacological stress testing appear inconsistent and comparably small, and do not appear to be correlated with inducible myocardial ischemia.

BACKGROUND: This study sought to determine whether preoperatively measured high-sensitivity cardiac troponin T (hs-cTnT) and N -terminal pro-brain natriuretic peptide (NT-proBNP) improve cardiac risk prediction in patients undergoing major noncardiac surgery compared with the standard risk indices. METHODS: In this ancillary study to the Vitamins in Nitrous Oxide trial, patients were included who had preoperative hs-cTnT and NT-proBNP measured (n = 572). Study outcome was the incidence of postoperative myocardial infarction (MI) within the first 3 postoperative days. hs-cTnT was considered elevated if >14 ng/L and NT-proBNP if >300 ng/L. Additional cutoff values were investigated on the basis of receiver operating characteristic statistics. Biomarker risk prediction was compared with Lee’s Revised Cardiac Risk Index (RCRI) with the use of standard methods and net reclassification index. RESULTS: The addition of hs-cTnT (>14 ng/L) and NT-proBNP (>300 ng/L) to RCRI significantly improved the prediction of postoperative MI (event rate 30/572 [5.2%], Area under the receiver operating characteristic curve increased from 0.590 to 0.716 with a 0.66 net reclassification index [95% confidence interval 0.32–0.99], P < .001). The use of 108 ng/L as a cutoff for NT-proBNP improved sensitivity compared with 300 ng/L (0.87 vs 0.53). Sensitivity, specificity, positive, and negative predictive value for hs-cTnT were 0.70, 0.60, 0.09, and 0.97 and for NT-proBNP were 0.53, 0.68, 0.08, and 0.96. CONCLUSIONS: The addition of cardiac biomarkers hs-cTnT and NT-proBNP to RCRI improves the prediction of adverse cardiac events in the immediate postoperative period after major noncardiac surgery. The high negative predictive value of preoperative hs-cTnT and NT-proBNP suggest usefulness as a “rule-out” test to confirm low risk of postoperative MI.