Risk stratification with cardiac troponin I in patients undergoing elective coronary artery bypass surgery.
OBJECTIVE
Cardiac troponin I (cTnI) is a highly sensitive and specific marker for postoperative prediction of patients outcome after coronary artery bypass surgery (CABG). Whether preoperatively elevated cTnI levels similarly predict the outcome in patients scheduled for elective CABG is currently unknown.


METHODS
Therefore, a possible correlation between preoperative cTnI levels and perioperative major adverse events and in-hospital mortality after CABG was investigated. CTnI was measured within 24h before surgery in 1405 out of 3124 consecutive elective CABG patients. Out of these patients, 1178 had a preoperative cTnI level below 0.1ng/ml (group 1), 163 patients had a cTnI level between 0.11 and 1.5ng/ml (group 2), and 64 patients had a cTnI level above 1.5ng/ml (group 3). CTnI levels, electrocardiograms, clinical data, adverse events and in-hospital mortality were recorded prospectively. Patients with ST-elevation myocardial infarction less than 7 days before surgery were excluded from the study.


RESULTS
Perioperative myocardial infarction (PMI) occurred in 69/1178 patients (5.9%) in group 1, 14/163 patients (8.6%; odds ratio (OR) 1.5, 95% confidence interval (CI): 0.8-2.8) in group 2, and 11/64 patients (17.2%; OR 3.3, CI: 1.6-7.0) in group 3 (overall: P<0.001, Cochran-Armitage trend test). Low cardiac output syndrome (LCOS) occurred in 19/1178 patients (1.6%), 9/163 (5.5%; OR 3.6, CI: 1.5-8.5), and 7/64 patients (10.9%; OR 7.5, CI: 2.7-19.8) (overall: P<0.001, group 1 vs. group 2: P<0.002), respectively. In-hospital mortality was 1.7% in group 1 and 3.1% in group 2, but 6.3% (OR 3.9, CI: 1.1-12.5) in group 3 (overall: P<0.01, group 1 vs. group 2: P=NS). Intensive care and hospital stay were significantly longer in group 3 compared to groups 1 and 2. Univariate and multivariate logistic regression analysis confirmed the statistically significant relationship between cTnI and PMI, LCOS and in-hospital mortality, respectively (P<0.001).


CONCLUSIONS
Risk stratification by measurement of cTnI levels within 24h before elective CABG clearly identifies a subgroup of patients with increased risk for postoperative adverse outcome and in-hospital mortality.
Thielmann
Matthias
M
Department of Thoracic and Cardiovascular Surgery, West-German Heart Center Essen, University Clinic of Essen, Germany. matthias.thielmann@uni-essen.de
Massoudy
Parwis
P
Neuhäuser
Markus
M
Knipp
Stephan
S
Kamler
Markus
M
Marggraf
Günter
G
Piotrowski
Jarowit
J
Jakob
Heinz
H
D000368:Aged; D015415:Biomarkers / Q000097:blood; D001026:Coronary Artery Bypass / Q000401:mortality; D003327:Coronary Disease / Q000097:blood* / Q000401:mortality; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D007431:Intraoperative Complications / Q000097:blood / Q000401:mortality; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000401:mortality; D016017:Odds Ratio; D011184:Postoperative Period; D011446:Prospective Studies; D018570:Risk Assessment / Q000379:methods; D019210:Troponin I / Q000097:blood*
D015415:Biomarkers; D019210:Troponin I