Early identification of permanent myocardial damage after coronary surgery is aided by repeated measurements of CK-MB.
OBJECTIVE
ECG diagnosis of myocardial infarction after cardiac surgery is associated with major pitfalls and enzyme diagnosis is interfered by unspecific elevation unrelated to permanent myocardial injury. Sustained release of troponin-T is a marker of permanent myocardial injury if renal function is maintained. However, early identification of perioperative myocardial infarction is desirable and therefore the usefulness of creatine kinase monobasic (CK-MB) kinetics to detect myocardial injury early after coronary surgery was investigated.


METHODS
Two hundred and eighty-six patients undergoing coronary surgery were studied with respect to release of enzymes and troponin-T preoperatively and postoperatively 3 and 8 h after unclamping the aorta, and every morning postoperative days 1-4.


RESULTS
CK-MB peak was found at 3 h (n = 145), 8 h (n = 103) and 16-20 h after unclamping (n = 38). Depending on when the CK-MB peak was recorded different demographic and perioperative characteristics were found. A sustained release of troponin-T was characteristic for the group with the CK-MB peak at 16-20 h after unclamping.


CONCLUSIONS
If CK-MB is measured only once it may be advisable to do it on the first postoperative morning as these measurements provided the best discrimination between patients with and without sustained elevation of troponin-T. However, repeated sampling provides additional information that aids in the early identification of permanent myocardial injury particularly in patients with borderline elevations of CK-MB.
Dahlin
L G
LG
Department of Cardiothoracic Surgery, University Hospital, Linköping, Sweden. Lars-Goran.Dahlin@lio.se
Kågedal
B
B
Nylander
E
E
Olin
C
C
Rutberg
H
H
Svedjeholm
R
R
D000368:Aged; D015415:Biomarkers / Q000032:analysis*; D015331:Cohort Studies; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000379:methods*; D003402:Creatine Kinase / Q000032:analysis / Q000378:metabolism*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D046911:Macromolecular Substances; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D009203:Myocardial Infarction / Q000097:blood / Q000473:pathology* / Q000601:surgery*; D011184:Postoperative Period; D011300:Preoperative Care; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013997:Time Factors; D020107:Troponin T / Q000032:analysis / Q000378:metabolism*
D015415:Biomarkers; D046911:Macromolecular Substances; D020107:Troponin T; D003402:Creatine Kinase