Impact of Custodiol‐N Cardioplegia on Acute Kidney Injury After Cardiopulmonary Bypass

Myocardial protection during cardiopulmonary bypass (CPB) can be achieved using cardioplegic solutions. Although, acute kidney injury (AKI) is a common complication following CPB, the effects of cardioplegic solutions on AKI have rarely been investigated. Within this study, the effects of the cardioplegic solutions histidine‐tryptophan‐ketoglutarate (HTK; Custodiol®) and HTK‐N (Custodiol‐N®) on AKI in a large animal model were compared. Therefore, landrace pigs underwent median sternotomy, CPB at 34°C, 90 min of cardiac arrest and 120 min of reperfusion. Animals were randomized for single‐shot cardioplegia with either HTK (n=10) or HTK‐N (n=10). Renal biopsies and sera were analyzed to determine AKI biomarkers and apoptosis. Compared to HTK, HTK‐N induced a decreased extent of proximal tubule swelling (48.3±1.6 µm vs. 52.3±1.1 µm, p=0.05) and decreased cytochrome c release (0.26±0.04 vs. 0.46±0.08, p=0.04) without reaching statistical significance due to Bonferroni correction. Comparing baseline and postreperfusion levels, the hemoglobin (Hb) and blood calcium levels were lower in HTK‐N (Hb_baseline: 6.0±0.6 mmol/L, Hb_reperfusion: 6.2±0.7 mmol/L, p=0.12; Ca²⁺_baseline: 1.36±0.05mmol/L, Ca²⁺_reperfusion: 1.28±0.05mmol/L, p=0.16) compared to the HTK group (Hb_baseline: 5.9±0.4 mmol/L, Hb_reperfusion: 4.7±0.8 mmol/L, p<0.01; Ca²⁺_baseline: 1.34±0.07mmol/L, Ca²⁺_reperfusion: 1.24±0.06mmol/L, p<0.01). The present study showed that HTK‐N could positively affect the kidney during CPB. Hb and calcium levels were stabilized. A statistical trend was found showing that AKI‐related proximal tubule swelling and cytochrome c release were diminished.