Mechanoenergetic function and troponin T release following cardioplegic arrest induced by St Thomas' and histidine-tryptophan-ketoglutarate cardioplegia – an experimental comparative study in pigs☆☆☆

Abstract

The study compares the single dose histidine-tryptophan-ketoglutarate (HTK) cardioplegia to the repeatedly delivered St Thomas' Hospital Solution (STHS) with respect to preservation of left ventricular mechanoenergetics and leakage of troponin T in a porcine experimental model. Fourteen pigs were randomized to a single infusion of 30 ml/kg HTK cardioplegia (n=7) or 500 ml STHS (n=7) followed by 200 ml after 20 and 40 min. After 1 h of aortic cross-clamping on cardiopulmonary bypass (CPB), the pigs were weaned and the hearts reperfused for 4 h. Stroke work (SW) was determined by a conductance catheter in the left ventricle. Myocardial oxygen consumption (MvO(2)) was measured as a function of coronary blood flow and arterial-to-coronary sinus oxygen saturation difference. Troponin T was sampled from the coronary sinus. The slope of the SW-MvO(2) relationship increased by 1.09 (+/-0.53) in the HTK group compared with 0.33 (+/-0.70) in the STHS group following ischemia and 4 h of reperfusion (P=0.04). Troponin T was significantly higher in the HTK group compared with the STHS group (P=0.04). Repeatedly delivered STHS gives better preservation of postischemic mechanoenergetic function and lower troponin T release compared with single dose HTK cardioplegia, indicating improved cardioprotection with STHS.

The Comparison of the Effects of Bretschneider's Histidine‐Tryptophan‐Ketoglutarate and Conventional Crystalloid Cardioplegia on Pediatric Myocardium at Tissue Level

“…This is the case with the Bretchneider's histidine‐tryptophan‐ketoglutarate (HTK) solution. These two strategies have been compared clinically and experimentally ; however, there is no consensus on which solution provides a better myocardial protection. The clinical studies comparing the two solutions are mostly on adult patients.…”

“…compared clinically and experimentally (2)(3)(4)(5); however, there is no consensus on which solution provides a better myocardial protection. The clinical studies comparing the two solutions are mostly on adult patients.…”

Which Is the Better Option During Neonatal Cardiopulmonary Bypass

“…This might attributed to the good qualities of HTK, including high buffer capacity, ketoglutarate to improve the ATP energy production, and tryptophan to stabilize the cell membrane. 12 On the other hand, immature hearts have higher resting concentrations of free amino acids which are consumed by ischemic myocardium, 13 and they can produce more alanine, succinate, and malate during ischemia, and have better recovery of postischemic aerobic metabolism.…”

“…[3][4][5] Experimental studies have shown, however, that HTK solution provides inadequate cardioprotection when compared to CBC. 6,7 The relative advantage of blood cardioplegia in relation to crystalloid cardioplegia is still the subject of debate in pediatric cardiac surgery. 8,9 Angeli et al 10 reported that HTK solution was applied to newborns undergoing arterial switch operations with a mean of 98 minutes of cardiac arrest; however, the authors did not use any control group.…”

“…Moreover, the safety of HTK used for prolonged ischemic time (over 75 minutes) has not been documented. 3,6,7 Our previous study showed that HTK solution results in less spontaneous ventricular fibrillation and lower mortality when compared to St. Thomas solution, and HTK is valid for complex congenital cardiac surgery with a prolonged cross-clamping time (105-242 minute). 11 Therefore, we wanted to compare the effect of cold HTK with that of CBC, which was assumed to be the best cardioplegia method, on a neonatal piglet model.…”