Comparison of Serum Markers of Myocardial Ischemia in Coronary Artery Bypass Grafting by On-pump and Off-Pump Techniques

Coronary artery bypass grafting (CABG) is usually performed with cardiopulmonary bypass (CPB). However CPB has been associated with several adverse effects. Recently off-pump CABG technique is offered as an alternative to the standard on-pump technique. The purpose of this study was to evaluate the safety of the techniques by estimating and comparing serum markers of myocardial ischemia; CK, CK-MB, LDH, AST, Cardiac Troponin I and some peri- and postoperative complications after the two types of surgical procedures.
Seventy-three patients (58 males and 15 females) with angiographically defined CAD admitted to the hospital for CABG were selected. The off-pump technique was performed in 38 patients with mean age of 60±10.5 years. In 35 other patients with mean age of 55±10.4 years, the on-pump technique was applied. CK, CK-MB, LDH and AST activities and cardiac Troponin I concentration were measured peri- and postoperatively until 24 hours. Characteristics of the patients and some peri- and postoperative data regarding incidence of complication were also recorded.
The activities of serum cardiac enzymes; CK, CK-MB, LDH and AST after on-pump CABG technique were higher than those of off-pump technique (p<0.05 in all cases). The levels of Troponin I were significantly higher after on-pump CABG throughout the entire measurement period (p<0.01) compared off-pump procedure. In the both groups of the patients no preoperative myocardial infarction was observed. In the off-pump technique procedural time was shorter and transfusion of blood and blood products was less than those of on-pump technique, but no differences were noticed between the other recorded data.
Significantly lower release of the enzymes and Troponin I during operation by off-pump technique suggests that the technique causes less myocardial injury. On the basis of little change in the activities of cardiac enzymes and Troponin I in serum and presented data including a marked decrease in blood transfusion and shorter procedural time it is concluded that off-pump CABG is a safe and effective technique in selected patients with appropriate coronary lesions.