Monocyte Activation in On-Pump Versus Off-Pump Coronary Artery Bypass Surgery

Greilich, Philip E.; Brouse, Chad F.; Rinder, Henry M.; Jessen, Michael E.; Rinder, Christine S.; Eberhart, Robert C.; Whitten, Charles W.; Smith, Brian R.

doi:10.1053/j.jvca.2007.08.009

« Previous Next »Journal of Cardiothoracic and Vascular Anesthesia
Volume 22, Issue 3 , Pages 361-368, June 2008

Monocyte Activation in On-Pump Versus Off-Pump Coronary Artery Bypass Surgery

Philip E. Greilich, MD, FAHA
- Department of Anesthesiology and Pain Management, UT Southwestern Medical Center, Dallas, TX
- Address reprint requests to Philip E. Greilich, MD, FAHA, Department of Anesthesiology & Pain Management, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-9202.
Chad F. Brouse, MS
- Department of Anesthesiology and Pain Management, UT Southwestern Medical Center, Dallas, TX
Henry M. Rinder, MD
- Department of Laboratory Medicine, Yale University Medical Center, New Haven, CT.
Michael E. Jessen, MD
- Department of Cardiovascular and Thoracic Surgery, UT Southwestern Medical Center, Dallas, TX
Christine S. Rinder, MD
- Department of Anesthesiology, Yale University Medical Center, New Haven, CT
Robert C. Eberhart, PhD
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX
Charles W. Whitten, MD
- Department of Anesthesiology and Pain Management, UT Southwestern Medical Center, Dallas, TX
Brian R. Smith, MD
- Department of Laboratory Medicine, Yale University Medical Center, New Haven, CT.

published online 12 November 2007.

Objective: Monocyte activation plays a key role in amplifying both inflammatory and coagulopathic sequelae in patients undergoing on-pump coronary artery bypass graft (CABG) surgery. Off-pump CABG diminishes, but does not eliminate, the systemic inflammatory response and its influence on monocyte activation remains unclear. This study was performed to determine if off-pump CABG suppresses all features of monocyte activation.

Design: Prospective, controlled, clinical study.

Setting: University-affiliated veterans affairs hospital and laboratory.

Participants: Twenty-two patients scheduled to undergo primary CABG surgery (11 on-pump and 11 off-pump).

Interventions: On-pump and off-pump CABG surgery was performed via median sternotomy. Anticoagulation and heparin reversal were identical. Moderate hypothermia (28°-30°C) was used for on-pump CABG surgery, whereas temperature was maintained above 35.5°C for off-pump CABG. No antifibrinolytic agents were used.

Measurements and Main Results: Perioperative monocyte changes were assessed by using cellular (CD11b, monocyte-platelet conjugates) and secreted markers (plasma IL-6, IL-8, and IL-10) measured at 6 time points before, during, and after CABG surgery. Off-pump CABG surgery completely blocked the increases in monocyte CD11b expression (p < 0.001) and monocyte-platelet conjugate formation (p < 0.001) observed in the on-pump group. In contrast, plasma interleukin levels were significantly elevated in both groups, although off-pump CABG surgery resulted in lower levels (p < 0.001) and a delayed time course.

Conclusions: Off-pump CABG surgery attenuates monocyte secreted cytokines and completely suppresses activation-dependent monocyte cell-surface changes (CD11b, monocyte-platelet conjugate formation). Whether these pathophysiologic differences in monocyte activation translate into a reduction in adverse events after CABG surgery warrants a larger, randomized, outcomes study.

Key words: Cardiopulmonary bypass, monocyte activation, monocyte CD11b, monocyte-platelet adhesion, coronary artery bypass surgery, systemic inflammatory response