Stimulation of neutrophil integrin expression during coronary artery bypass grafting: comparison of crystalloid and blood cardioplegic solutions

Acute-phase proteins and oxidative stress in patients undergoing coronary artery bypass graft: comparison of cardioplegia strategy

Introduction

Several strategies are still being introduced to cardiac surgery techniques to reduce the signs of the inflammatory response and oxidative stress. Many efforts have been made to develop the best possible method for myocardial protection.

Aim

To assess the effect of the cardioplegia strategy on the systemic inflammatory response and oxidative stress.

Material and methods

A group of 238 consecutive, elective on-pump coronary artery bypass graft patients (CABG; 183 men, aged 64.6 ±8.1 years) were prospectively studied. Patients were enrolled in two groups: with warm blood cardioplegia (n = 124) and with cold crystalloid cardioplegia (n = 114). In each group, pre- and postoperative levels of plasma C-reactive protein, fibrinogen, interleukin 6 and 8-iso-prostaglandin F_2α (8-iso-PGF_2α) were measured.

Results

All studied markers significantly increased 18–36 h following CABG and then decreased in 5–7 postoperative days but remained above baseline levels. No differences in terms of studied markers and clinical outcomes were noted for the different types of cardioplegia. Regression analysis showed a significant correlation between preoperative level of oxidative stress measured by 8-iso-PGF_2α and postoperative myocardial infarction as well as in-hospital cardiovascular death (p = 0.047 and p = 0.041 respectively).

Conclusions

This study extends previous reports by showing that the type of cardioplegia does not affect the systemic inflammatory response or oxidative stress, which are associated with the CABG procedure. It might be speculated that preoperative screening of oxidative stress could be helpful in identifying patients at increased risk of an unfavorable course after CABG.

CD11b may be a less satisfactory indicator for cardiac ischemia-reperfusion injury in coronary artery bypass graft surgery with cardiopulmonary bypass than cardiac troponin I

STUDY OBJECTIVE

To investigate whether CD11b on neutrophils can be used as a marker to predict myocardial ischemia-reperfusion injury for patients undergoing coronary artery bypass graft (CABG) surgery on cardiopulmonary bypass (CPB).

DESIGN

Prospective, observational study.

SETTING

University teaching hospital and university hospital laboratories.

PATIENTS

Twelve adults, physical status II and III (American Society of Anesthesiologists) patients scheduled for elective CABG surgery on CPB.

INTERVENTIONS

Anesthesia and surgical interventions were performed according to standard procedures. Coronary sinus was cannulated for retrograde cardioplegia perfusion and for coronary sinus blood sampling. The blood samples were collected from systemic and coronary venous sinus blood respectively at several time points before CPB, during CPB, and after declamping of the ascending aorta.

MEASUREMENTS AND MAIN RESULTS

CD11b expressions in systemic circulation blood increased significantly during CPB and maintained higher levels after cardiac reperfusion (P < .05); on the other hand, CD11b expressions in coronary sinus blood declined gradually and reached their lowest level at 5 minutes after aortic declamping. The differences in CD11b expressions between systemic circulatory blood and coronary sinus blood after cardiac reperfusion were significant (P < .05). Cardiac troponin I (cTnI) concentrations in both systemic circulatory blood and coronary sinus blood increased significantly after cardiac reperfusion (P < .05), and the concentrations of cTnI in coronary sinus blood increased much higher than the corresponding concentrations of cTnI at each time point (P < .05).

CONCLUSION

CD11b expression on neutrophils may not be a reliable predictor for myocardial ischemia-reperfusion injury in CABG surgery on CPB because of the possible sequestration of neutrophils in myocardium.

Transcardiac release of soluble adhesion molecules during coronary artery bypass grafting: effects of crystalloid and blood cardioplegia

BACKGROUND

Dysfunction of myocardium as a result of ischemia/reperfusion during coronary artery bypass grafting (CABG) is currently one of the biggest problems in cardiovascular surgery. In previous studies, it has been well established that activated leukocytes and coronary vascular endothelial cells play an important role in the development of cardiac tissue damage during ischemia followed by reperfusion. Interactions between both of these cell types require the expression of adhesion molecules on their surface. In certain conditions, on cell activation, the adhesion proteins may be released from activated cells in soluble form into circulation. The purpose of our study was to establish whether the use of blood cardioplegia modifies plasma levels of soluble intracellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble E-selectin (sE-selectin), and soluble L-selectin (sL-selectin) in comparison with crystalloid cardioplegia in patients undergoing CABG.

METHODS

Patients undergoing CABG were classified into two groups to receive cold crystalloid cardioplegia (St. Thomas' Hospital) or cold blood cardioplegia (method of Buckberg), followed by a "warm-shot" of the solution. Coronary sinus and arterial blood samples were obtained from 50 patients (42 men and 8 women; age range, 34 to 73 years) before aortic cross-clamping, at the beginning of reperfusion, and after 30 min of reperfusion. Plasma levels of soluble adhesion molecules were measured using sensitive enzyme-linked immunosorbent assays.

RESULTS

The transcardiac release of sICAM-1 and sVCAM-1 following myocardial ischemia/reperfusion during CABG was evident in both groups of patients. However, the increase of soluble forms of both of these adhesion proteins was more significant in the group of patients receiving crystalloid cardioplegia. Crystalloid cardioplegia resulted in decreased plasma level of sE-selectin in the coronary sinus blood sample after 30 min of reperfusion. No significant changes in plasma levels of sL-selectin in either group were observed.

CONCLUSION

Cardioplegia may affect the release of soluble forms of adhesion molecules from ischemic myocardium and modify endothelium activation in patients undergoing CABG.