Remote Ischemic Preconditioning Does Not Prevent White Matter Injury in Neonates

Abstract

Remote ischemic preconditioning (RIPC) is a mechanism to protect tissues from injury during ischemia and reperfusion. We investigated the neuroprotective effects of RIPC in neonates undergoing cardiac surgery. The outcome was white matter injury (WMI), assessed by the change in volume of WMI from preoperative to postoperative brain magnetic resonance imaging (MRI). Patients were randomized to RIPC or SHAM. RIPC was induced prior to cardiopulmonary bypass by four 5-minute cycles of blood pressure cuff inflation to produce ischemia of the lower extremity. For patients randomized to SHAM, the cuff was positioned, but not inflated. The study included 67 patients, with 33 randomized to RIPC and 34 randomized to SHAM. Preoperative and postoperative MRIs were available in 50 patients, including 26 of the 33 RIPC patients and 24 of the 34 SHAM patients. There were no differences in baseline and operative characteristics for either the overall study group or the group with evaluable MRIs. WMI was identified in 28% of the patients preoperatively and in 62% postoperatively. There was no difference in the prevalence of WMI by treatment group (p > 0.5). RIPC patients had an average change in WMI of 600 mL3, and SHAM subjects had an average WMI change of 107 mL3. There was no significant difference in the mean value of WMI change between patients who received RIPC and those who received SHAM treatments (p= 0.178). In this randomized, blinded clinical trial, there was no evidence that use of RIPC provides neuroprotection in neonates undergoing repair of congenital heart defects with cardiopulmonary bypass.