Effect of cardiopulmonary bypass on tissue injury markers and endothelial activation during coronary artery bypass graft surgery

BACKGROUND: Coronary artery bypass grafting (CABG) is done either using cardiopulmonary bypass (CPB) or without using CPB (OPCAB). But, recently, reports have shown that CPB is associated with increased postoperative morbidity because of the involvement of many systems. AIMS: The aim of this prospective study was to evaluate the influence of the technique of surgery on various tissue injury markers and the extent of endothelial activation in patients undergoing CABG and OPCAB coronary revascularization. SETTINGS AND DESIGN: This study was conducted at a tertiary healthcare center during the period May 2008 to December 2009. MATERIALS AND METHODS: This was a prospective nonrandomized blinded study. The activities of Creatine Phosphokinase (CK) and its isoenzyme CK-MB, Lactate dehydrogenase (LDH), levels of cardiac Troponin I, soluble vascular cell adhesion molecule-1 (sVCAM-I) and systemic nitric oxide production were assessed. STATISTICAL ANALYSIS: All the results were expressed as Mean ± SD. P value ≤ 0.05 was considered significant. The statistical analysis was carried out using SPSS Version 11.5-computer software (SPSS Inc., Chicago, IL, USA). RESULTS: The surgical trauma had elevated CK, CK-MB and Troponin I in both the groups and further elevation was seen in the CABG group in comparison to OPCAB (P<0.001). The Troponin I concentrations showed an increase from 0.11 ± 0.02 preoperatively to 6.59 ± 0.59 (ng/ml) at 24 h (P<0.001) compared to the OPCAB group. Mean serum levels of sVCAM-1 increased significantly after surgery in both the groups (P<0.02). To determine serum nitric oxide (NO) production, NO2- and NO3- (stable end products of NO oxidation) were analyzed which also increased significantly at 24 h in both the groups. But the increase was not significant at 48 h in both the groups compared to the preoperative value in our study. CONCLUSION: The present study indicates that, despite comparable surgical trauma, the OPCAB significantly reduces tissue injury. The overall pattern of endothelial activation after OPCAB is significantly lower than that after CABG. This may contribute to improved organ function, and improved postoperative recovery.