Objective: To compare markers of cardiac injury, inflammatory and oxidative responses, and myocardial cellular changes in the left and right ventricles of patients undergoing isolated coronary artery bypass grafting (CABG) or aortic valve replacement (AVR) using cardiopulmonary bypass (CPB) and cardioplegic arrest with or without remote ischaemic preconditioning (RIPC).
Methods: Two conditions were studied for each surgical stratum (CABG or AVR): (a) no RIPC and (b) RIPC following anaesthesia and before sternotomy. The control group (no RIPC) represented standard clinical practice. Left and right ventricular biopsies were collected before CPB and at the end of ischaemic cardioplegic arrest. Blood samples were collected before, during, and after the operation.
Results: Between March 2012 and April 2014, 124 patients agreed to participate in the study; 64 and 60 patients formed the CABG and AVR populations, respectively, and were randomised to receive RIPC or sham treatment. There were no differences in troponin release between groups (geometric mean ratio 0.92 (0.75,1.10), p=0.9; and 0.9 (0.35,1.44), p=0.65 CABG and AVR respectively). The postoperative course in each group was similar with no mortality. There were no significant differences in phosphorylation potential or energy charge in left and right ventricle biopsies or in circulating inflammatory markers between groups. No serious adverse events were reported.
Conclusions: RIPC did not confer significant cardioprotection as measured by troponin I release. This result was possibly related to the inability of the study to stratify anaesthesia regimens. Both RIPC and Tru-Cut ventricle biopsy procedures were safe.