Cardiac troponin T for prediction of short- and long-term morbidity and mortality after elective open heart surgery.
BACKGROUND
Increased cardiac troponins in blood are observed after virtually every open heart surgery, indicating perioperative myocardial cell injury. We sought to determine the optimum time point for blood sampling and the respective cutoff value of cardiac troponin T (cTnT) for risk assessment in patients undergoing cardiac surgery.


METHODS
In a series of 204 patients undergoing scheduled open heart surgery, mainly for coronary artery bypass grafting (n = 132) or valve repair (n = 27), cTnT concentrations were measured before and 4 and 8 h after cross-clamping and then daily for 7 days. Individual risk was assessed by use of the Cleveland Clinic Foundation Risk score and intraoperative risk indicators such as duration of cardiopulmonary bypass, cross-clamping, and perioperative release of cardiac markers. Patients were followed for 28 months.


RESULTS
Cardiac mortality, all-cause mortality rates, and rates of nonfatal acute myocardial infarction (AMI) at 28 months were 6.9%, 8.8%, and 6.8%, respectively. cTnT was higher in patients with Q-wave AMI or postoperative heart failure requiring inotropic support, and in nonsurvivors. The ROC curve revealed a cTnT > or = 0.46 microg/L at 48 h as the optimum discriminator for long-term cardiac mortality. Stepwise logistic regression identified higher Cleveland Clinic Risk Score [odds ratio (OR) = 2.6 per point], cross-clamp time >65 min (OR = 6.6), and cTnT (OR = 4.9) as significant and independent predictors of long-term cardiac mortality.


CONCLUSIONS
A single postoperative cTnT measurement can be used to estimate myocardial cell injury that impacts long-term survival after open heart surgery. It adds independently to established risk indicators.
Lehrke
Stephanie
S
Johns Hopkins University, Department of Cardiology, Baltimore, MD, USA.
Steen
Henning
H
Sievers
Hans H
HH
Peters
Hanno
H
Opitz
Armin
A
Müller-Bardorff
Margit
M
Wiegand
Uwe K H
UK
Katus
Hugo A
HA
Giannitsis
Evangelos
E
D000368:Aged; D002318:Cardiovascular Diseases / Q000097:blood* / Q000601:surgery*; D001026:Coronary Artery Bypass / Q000401:mortality*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D016896:Treatment Outcome; D020107:Troponin T / Q000097:blood*
D020107:Troponin T