Table 4.

Major recent studies showing elevations in Troponin T to be associated with mortality post-coronary artery bypass grafting surgery

Study	Type of study and surgery	Number of patients	Cardiac biomarker (time)	Time from CABG when biomarker level taken	Major findings
Januzzi et al.36	Prospective single centre study CABG only	224	cTnT CK-MB	Immediately post-op, 6–8 h and 18–24 h	cTnT level in the highest quintile (≥1.58 ng/mL; ≥15× URL) immediately post-op or at 18–24 h predicted in-hospital death. CK-MB levels did not offer additional prognostic benefit to cTnT in multivariate analysis
Lehrke et al.38	Prospective single centre study CABG and/or valve surgery	204	cTnT	4, 8 h then every day for 7 days	cTnT >0.46 μg/L (>46× URL) at 48 h after surgery was the optimum discriminator for long-term cardiac mortality (28 mths, OR 4.93)
Kathiresan et al.37	Prospective single centre study CABG only	136	cTnT CK-MB	Immediately post-op, 6–8 h and 18–24 h post-op	cTnT >1.58 μg/L at 18–24 h was the optimum discriminator for 1 year cardiac mortality (OR 5.45) Elevations in CK-MB were not predictive of mortality
Nesher et al.39	Retrospective observational single centre study Cardiac surgery (CABG and/or valve)	1918	cTnT	Single sample <24 h	cTnT level ≥0.8 μg/L (8× URL) was most discriminatory for MACE (30 day death, electrocardiogram-defined infarction, and low output syndrome) (OR 2.7) 0–3.9× URL 0.5% 30 day mortality 5–5.9× URL 1.6% 30 day mortality 6–7.9× URL 1.0% 30 day mortality 8–12.9× URL 1.8% 30 day mortality >13× URL 6.8% 30 day mortality
Muehlschlegel et al.26	Retrospective analysis CABG only	1013	cTnT	Daily from day 1 to 5	24 h cTnT rise > 110× URL HR 7.2 of 5 yr mortality cTnT at 24 h were independent predictors of 5 year mortality in a multivariate model (No additional benefit of measuring cTn beyond 24 h). Majority of patients had peak cTnI and CK-MB levels at 24 h. ECG changes alone did not predict 5 year mortality.
Mohammed et al.40	Prospective single centre study, retrospective analysis CABG only	847	cTnT	6–8 and 18–24 h	A cTnT of < 1.60 (<160× URL) had good negative predictive value for poor 30 day outcomes (death or heart failure)
Petaja et al.41	Meta-analysis CABG and/or valve surgery	2,547	cTnT	<48 h post op	≥7–16× URL: Short term mortality 3.2% vs. 0.5% for <7–16× URL elevation (RR 4.68–6.4); Long term mortality (12–28 mth) 16.1% vs. 2.3% (RR 5.7–10.09). (Pooled RR of mortality could not be calculated)
Søraas et al.30	Registry analysis, single centre study CABG only	1,350	cTnT CK-MB	7,20, 44 h post op	Patients with peak cTnT ≥ 5.4× URL had much higher long-term mortality (median 6.1 years) than those with <5.4× URL cTnT elevation. cTnT levels at 44 h postoperatively had a greater predictive value for long-term mortality than at 7 or 20 h. Peak Trop T levels predicted long-term mortality after multivariate analysis.
Wang et al.8	Retrospective analysis CABG only	560	hs-cTnT ECG/ECHO changes	12–24 h after CABG	In a multivariate model >10× URL rise in hs-TNT + ECG/ECHO evidence of recent MI or regional ischaemia predicted 30 day (HR 4.9) and long-term mortality (median follow-up 1.8 years) (HR 3.4). > 10× URL rise in hs-cTnT was seen in 90% patients.
Gober et al.42	Retrospective study from registry data CABG only	290	cTnT CK-MB	8,16 h post op	cTnT > 0.8 ng/mL (>80× URL) at 6–8 h was predictive of in hospital adverse outcomes and long term (4yr) mortality (OR 4.0). However, cTnT measured at 6–8 h was inferior to cTnT taken at 20 h in its prognostic ability.

AUC, area under the curve; CABG, coronary artery bypass grafting; CMR, cardiac MRI; CK-MB, creatine kinase-MB fraction; d, day; ECG, electrocardiogram; ECHO, echocardiocardiogram; HR, hazards ratio; h, hour; LGE, late gadolinium enhancement; LV, left ventricle; MACE, major adverse cardiac events; MI, myocardial infarction; mth, month; ng, nanogram; ONBEAT, on-pump beating heart; CABG ONSTOP, on-pump CABG; OR, odds ratio; post-op, post-operative; PMI, perioperative myocardial injury; RR, relative risk; TEE, transoesophageal echocardiogram; cTnI, Troponin I; cTnT, Troponin T; UA, unstable angina; URL, upper reference limit; yr, year.