Inappropriate myocardial protection is considered one of the main causes of mortality and morbidity in the correction of tetralogy of Fallot (TOF). Results of previous reports about the effects of ischemic postconditioning on myocardial protection in animals and humans are very encouraging. This randomized and controlled trial aimed to assess the effect of ischemic postconditioning on protection against myocardial ischemia reperfusion injury in TOF patients receiving cardioplegia.
From January 2008 to June 2010, 80 consecutive children undergoing correction of TOF were enrolled and randomly assigned to either a postconditioning group (three cycles of 30 seconds of ischemia and 30 seconds of reperfusion using re-clamping and de-clamping starting 30 seconds after the initial de-clamping of the aorta, n = 41) or a control group (n = 39). Cardiac troponin I (cTnI) was assayed preoperatively, and then 4 hours, 8 hours, 12 hours, 20 hours, and 48 hours after persistent reperfusion. The pre-, intra- and postoperative relevant data of all selected patients were analyzed. As a result, ischemic postconditioning reduced postoperative peak release by 45% for cTnI compared with the control group (0.43 ± 0.18 ng/mL versus 0.78 ± 0.15 ng/mL, P < 0.0001). Ischemic postconditioned patients had a lower peak inotropic score during the first postoperative 24 hours (5.6 ± 2.2 μg/kg/minute versus 8.6 ± 3.6 μg/kg/minute, P < 0.0001), extubation time (21.5 ± 7.3 hours versus 30.2 ± 12.4 hours, P = 0.0002) and length of ICU stay (43.4 ± 12.6 hours versus 56.3 ± 17.8 hours, P = 0.0003), while they had a higher cardiac output on the first postoperative day (1.41 ± 0.26 L/minute versus 1.28 ± 0.25 L/minute, P = 0.0255) as compared to the control group.
In conclusion, ischemic postconditioning may to some extent provide myocardial protection in children undergoing correction of tetralogy of Fallot.