A comparison of cardiac troponin T and creatine kinase-MB for patient evaluation after cardiac surgery.
OBJECTIVE
The aim of this study was to assess the role of serum markers of myocardial necrosis after cardiac surgery.


BACKGROUND
The role of serum troponin T (TnT) and creatine kinase-MB (CK-MB) for the risk stratification of patients after cardiac surgery remains undefined.


METHODS
Serum levels of TnT and CK-MB were measured from 224 patients every 8 h after cardiac surgery. The results of serum cardiac marker testing were correlated with adverse events, including new myocardial infarction (MI), cardiogenic shock or death. Univariable analysis identified factors predictive of complications, while stepwise logistic regression identified independent predictors of postoperative complications.


RESULTS
Cardiac marker elevation was universal after cardiac surgery. At all time points measured, compared with those patients without complications, the TnT levels from patients with complications were more significantly elevated (all: p < 0.0005). In contrast, among identically timed specimens, the levels of CK-MB from complicated patients were less reliably discriminatory. Multivariable analysis suggested that a TnT level in the highest quintile (> or = 1.58 ng/ml) was the strongest predictor of complications, including death (post-op, odds ratio [OR] = 31.0, 95% confidence interval [CI] = 3.67 to 263.1, p = 0.002) or shock (post-op: OR = 18.9, 95% CI = 2.29 to 156.1, p = 0.006; 18 h to 24 h: OR = 30.7, 95% CI = 3.75 to 250.7, p = 0.001), as well as the composite end points of death/MI (18 h to 24 h: OR = 60.1, 95% CI = 7.34 to 492.1, p < 0.0005), shock/MI (post-op: OR = 23.3, 95% CI = 2.82 to 191.4, p = 0.003; 18 h to 24 h: OR = 37.8, 95% CI = 4.66 to 307.3, p = 0.001) or death/shock/MI (post-op: OR = 20.0, 95% CI = 2.81 to 142.0, p = 0.003; 18 h to 24 h: OR = 67.4, 95% CI = 6.96 to 652.3, p < 0.0005). In contrast, in the presence of TnT, the results of CK-MB measurement added no independent prognostic information.


CONCLUSIONS
Troponin T is superior to CK-MB for the prediction of impending complications after cardiac surgical procedures.
Januzzi
James L
JL
Cardiology Division, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
Lewandrowski
Kent
K
MacGillivray
Thomas E
TE
Newell
John B
JB
Kathiresan
Sekar
S
Servoss
Stephen J
SJ
Lee-Lewandrowski
Elizabeth
E
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D001026:Coronary Artery Bypass; D003402:Creatine Kinase / Q000097:blood*; D052279:Creatine Kinase, MB Form; D004562:Electrocardiography; D005260:Female; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D007362:Intensive Care Units; D007527:Isoenzymes / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D011183:Postoperative Complications / Q000097:blood / Q000175:diagnosis*; D020107:Troponin T / Q000097:blood*
D015415:Biomarkers; D007527:Isoenzymes; D020107:Troponin T; D003402:Creatine Kinase; D052279:Creatine Kinase, MB Form