Intermediate and high peri-operative cardiac enzyme release following isolated coronary artery bypass surgery are independently associated with higher one-year mortality.
BACKGROUND
The relationship between cardiac enzyme (CE) release following coronary artery bypass surgery (CABG) and medium term outcome is unclear. We sought to determine the relationship between post-operative CE release and one-year survival following isolated CABG.


METHODS
Over three years 3,024 consecutive patients underwent isolated CABG. Patient characteristics were prospectively recorded in a cardiac surgical database. CE release, taken as the highest single measurement recorded in the first 24 hours post-op, was abstracted from an electronic archive. All cause mortality was taken from a national registry of deaths.


RESULTS
Data were complete for 2,860 (94.6%) patients. CK-MB isoenzyme (reference range 5-24 U/l) was recorded in 2,568 (89.8%), total CK in 292 (10.2%). CE release three or more times the upper limit of the reference range (ULR) were recorded in 498 (17.4%) patients, 163 (5.7%) patients had CE more than six times ULR. There were 122 deaths (4.3%). Cox proportional hazards analysis showed that CE release 3-6 times ULR (adjusted HR 2.1 [95% CI: 1.6 to 2.6], p = 0.002) and CE release six or more times the ULR (adjusted HR 5.0 [95% CI: 4.5 to 5.4], p < 0.001) were independently associated with increased one-year mortality.


CONCLUSIONS
Cardiac enzyme release following CABG is associated with increased one-year all-cause mortality. The definition of peri-operative myocardial infarction following CABG should include elevation of CK-MB three or more times the upper limit of normal.
Newall
N
N
Department of Cardiology, Arrowe Park Hospital, Wirral, UK. newall@attglobal.net
Oo
A Y
AY
Palmer
N D
ND
Grayson
A D
AD
Hine
T J
TJ
Stables
R H
RH
Fabri
B M
BM
Ramsdale
D R
DR
D000368:Aged; D001026:Coronary Artery Bypass / Q000401:mortality*; D052279:Creatine Kinase, MB Form / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D011446:Prospective Studies; D013997:Time Factors
D052279:Creatine Kinase, MB Form