The effect of cardiac surgery on peripheral blood lymphocyte populations.

Abstract

BACKGROUND: Cardiac surgery using cardiopulmonary bypass (CPB) is associated with some adverse postoperative complications caused by an altered immune response. An alternative approach to cardiac surgery, operating without the use of CPB (i.e. off-pump surgery), seems to display less adverse impacts on the immune response. Patients and METHODS: Peripheral blood lymphocytes in 40 patients undergoing cardiac surgery either with CPB ("on-pump") or without CPB ("off-pump") were followed using flow cytometry. The samples of peripheral blood were taken at five intervals: preoperatively, after termination of the surgery, on the first, on the third and on the seventh postoperative day, respectively. RESULTS: The most substantial changes appeared on the first postoperative day in both subgroups of patients. While the percentage of both total T cells and CD4+ T cells were decreased, the percentage of HLA-DR+ activated lymphocytes was increased. These changes were more profound in the "on-pump" subgroup compared to the "off-pump" subgroup. CONCLUSION: Our results may suggest that the "off-pump" surgical approach reveals less adverse impact on adaptive immune responses.