A comparison of cardiac post-conditioning and remote pre-conditioning in paediatric cardiac surgery.

BACKGROUND

Remote ischaemic pre-conditioning and cardiac ischaemic post-conditioning provide myocardial protection in cardiac surgery. However, these two endogenous strategies have not been directly compared in a clinical setting. The purpose of this study was to compare the efficacy of remote ischaemic pre-conditioning and post-conditioning in providing myocardial protection to children undergoing cardiopulmonary bypass for surgical repair of ventricular septal defect.

METHODS

We randomly assigned 60 paediatric patients scheduled for surgical correction of congenital ventricular septal defect to the post-conditioning group (n = 20), remote pre-conditioning group (n = 20), or control group (n = 20). Post-conditioning consisted of 30 seconds of ischaemia and 30 seconds of reperfusion achieved by clamping and unclamping the aorta, repeated three times over 3 minutes immediately after cardioplegic arrest. Remote ischaemic pre-conditioning consisted of 5 minutes of lower limb ischaemia followed by 5 minutes of reperfusion using a blood-pressure cuff inflated to a pressure of 200 millimetres of mercury, also repeated three times over 30 minutes. We assayed creatine kinase-MB, troponin I.

RESULTS

Mean age, cardiopulmonary bypass times, and aortic cross-clamp times were matched across groups. Both post-conditioning and remote ischaemic pre-conditioning reduced the peak release of creatine kinase-MB (86.1 plus or minus 24.1 units per litre and 92.8 plus or minus 20.6 units per litre, respectively, versus 111.0 plus or minus 44.6 units per litre in the control, p less than 0.05) and troponin I (0.28 plus or minus 0.10 nanogram per millilitre and 0.26 plus or minus 0.09 nanogram per millilitre, respectively, versus 0.49 plus or minus 0.19 nanogram per millilitre in the control group, p less than 0.05).

CONCLUSIONS

Our study demonstrates that ischaemic post-conditioning and remote ischaemic pre-conditioning provide comparable myocardial benefit in children undergoing cold blood cardioplegic arrest.