Can preoperative modelling of individual neutrophil adhesion responses predict renal morbidity?

Perioperative upregulation of the neutrophil adhesion molecule CD11b is associated with the development of renal impairment. We hypothesised that individual variation in neutrophil adhesion molecule responses to surgery influences renal outcomes and that this individual variability could be modelled prior to surgery and used to predict high risk patients. The developed model uses preoperative exposure of an individual patient's neutrophils to a fixed inflammatory stimulus and assessment of the basal and stimulated adhesion molecule CD11b expression.

Neutrophils were isolated from human volunteers undergoing cardiac surgery with cardiopulmonary bypass support. Basal and stimulated CD11b expression was measured using flow cytometry in preoperative neutrophil samples and compared to postoperative clinical performance.

Patients with low levels of preoperative basal neutrophil CD11b expression had the greatest increase in CD11b following phorbol-12-myristate-13-acetate stimulation. This stimulated CD11b response correlated with changes in CD11b expression from preoperative to postoperative sampling. Preoperative basal CD11b expression showed a significant inverse relationship with postoperative creatinine levels. However, preoperative CD11b stimulation was not related to postoperative renal function. In addition preoperative basal CD11b expression correlated with adrenaline requirements and intra-aortic balloon pump usage. In contrast stimulated CD11b expression was significantly related to length of hospital stay and changes in the A-a gradient.

Preoperative CD11b expression assessment might enable preoperative identification of patients who will mount an exaggerated and damaging neutrophil response to surgery which contributes to renal injury. Identification of these patients would then allow selective application of immunomodulatory therapies.