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Indexed/Abstracted in: BIOSIS Previews, EMBASE, Scopus, Emerging Sources Citation Index
Ypsilantis P. 1, Didilis V. 2, Bougioukas I. 2, Tsigalou C. 3, Simopoulos C. 1, Kampouromiti G. 3, Sivridis E. 4, Bougioukas G. 2
1 Laboratory of Experimental Surgery, Medical School, Democritus University of Thrace, Alexandroupolis, Greece;
2 Thoracic and Cardiac Surgery Clinic, Medical School, Democritus University of Thrace Alexandroupolis, Greece;
3 Laboratory of Biochemistry, University General Hospital of Alexandroupolis Alexandroupolis, Greece;
4 Laboratory of Pathology, Medical School Democritus University of Thrace, Alexandroupolis, Greece
Aim. The reliability of biochemical markers in the diagnosis of perioperative myocardial infarction (poMI) has been questioned. The aim of this study was to determine the temporal profiles of creatine kinase MB mass (CK-MBm), cardiac troponin I (cTnI) and of other conventional enzymes that are routinely measured postoperatively, and to evaluate them as potential diagnostic markers of poMI after lateral thoracotomy in a rabbit model.
Methods. Sixteen White New Zealand rabbits were assigned to 2 groups; in the first group (MI group, n=8), MI was induced by ligation of a coronary artery, after lateral thoracotomy, while in the second (control group, n=8) pericardiotomy only was performed. Serial blood samples were collected, preoperatively, prior to thoracotomy, 1, 3, 6, 12 and 24 h postinfarction and thereafter on a daily basis until the 12th postoperative day. The activities of AST, ALT, LDH and CK, as well as the concentrations of CK-MBm and cTnI, were measured in blood serum. The enzyme temporal profiles and critical time points of their time course were determined and their corrected relative increase was calculated.
Results. All enzymes were increased (P<0.05) from baseline level in both groups, except cTnI which was increased only in the MI group, demonstrating its cardiospecificity. However, AST, ALT and CK-MBm levels in the control group did not exceed the upper reference limits (URLs). CTnI exhibited the highest corrected relative increase (P<0.05) during the first 24 h as well as during the entire study period. The earliest enzyme increase was noted in cTnI (3rd hour post-MI) and the latest decrease in ALT (7th day) followed by cTnI (5th day). All enzymes peaked at the 12th hour, except ALT (2nd day).
Conclusion. Cardiac TnI is a more reliable diagnostic marker of poMI after lateral thoracotomy, compared to CK-MBm and other conventional enzymes, due to its cardiospecificity, high relative increase and persisted elevation in the blood circulation. Nevertheless, AST, ALT and CK-MBm could also be used as biochemical markers suggestive of poMI, which should then be verified by cTnI.