The Myocardial Protection of Polarizing Cardioplegia Combined With Delta-Opioid Receptor Agonist in Swine

摘要

StatisticsResultsThe purpose of this study was to determine whether polarized arrest using adenosine/lidocaine cold crystalloid cardioplegia in combination with the hibernation inductor δ-opioid receptor agonist pentazocine would give satisfactory myocardial protection rather than using depolarized supranormal potassium cardioplegia, supranormal potassium cardioplegia with pentazocine, or adenosine/lidocaine cardioplegia.MethodsTwenty pigs were randomly divided into four groups (n = 5 each) to receive the four types of cold crystalloid cardioplegia with an aortic cross-clamp time of 1 hour. Hemodynamic data were continuously measured, as was the left ventricular end-diastolic pressure (LVEDP), left ventricular end-systolic pressure (LVESP), plus or minus derivative of change in diastolic pressure over time (±dp/dt), cardiac output, pulmonary artery pressure, pulmonary capillary wedge pressure, cardiac troponin I, and left ventricular ultrastructure.ResultsBoth the adenosine/lidocaine/pentazocine group and the adenosine/lidocaine group got significantly better results than the hyperkalemic and hyperkalemic pentazocine groups in improving hemodynamic values, pulmonary capillary wedge pressure, LVEDP, LVESP, ±dp/dt, cardiac output, cardiac troponin I values, and left ventricular ultrastructure. There were no statistical differences between the adenosine/lidocaine/pentazocine group and the adenosine/lidocaine group at 1 hour after cross-clamp removal; but at 2 hours after cross-clamp removal, the adenosine/lidocaine/pentazocine group stands out (LVEDP 3.3 ± 0.5, LVESP 122.5 ± 18.9, +dp/dt 2.9 ± 0.1, ?dp/dt 2.0 ± 0.6, cardiac output 2.6 ± 0.4, and troponin I 4.9 ± 0.5), with significant differences from the adenosine/lidocaine group (LVEDP 5.8 ± 1.0, LVESP 98.5 ± 10.1, +dp/dt 2.5 ± 0.2, ?dp/dt 1.0 ± 0.2, cardiac output 2.2 ± 0.2, troponin I 8.2 ± 0.8; p < 0.05). The defibrillation rate was largely decreased after the cross-clamp was released in the group containing pentazocine in cardioplegia.ConclusionsAdenosine/lidocaine/pentazocine cold crystalloid cardioplegia gave satisfactory cardiac arrest and better myocardial protection than the other three groups, especially with regard to improving prolonged postoperative cardiac function.Abbreviations and Acronyms: AL (adenosine/lidocaine), ALP (adenosine/lidocaine/pentazocine), ATP (adenosine triphosphate), CPB (cardiopulmonary bypass), cTnI (cardiac troponin I), dp/dt (derivative of change in diastolic pressure over time), K (hyperkalemic cardioplegia), KP (hyperkalemic cardioplegia with pentazocine), LVEDP (left ventricular end-diastolic pressure), LVESP (left ventricular end-systolic pressure), MAP (mean arterial pressure), PAP (pulmonary artery pressure)CTSNet classification:31Hyperkalemic cardioplegia (St. Thomas solution) has been the foundation of most myocardial protection strategies since its introduction more than 25 years ago. But apart from electrochemical arrest, these solutions are far from perfect. Myocardial membrane depolarization with potassium is associated with continued transmembrane ionic fluxes through sodium and calcium “window currents.” It gives ionic imbalance, intracellular sodium and calcium overload, and continued energy expenditure, which subsequently may cause contracture and myocardial injury. Cardiomyocyte dysfunction and death, microvascular injury, coronary vasoconstriction and spasm, arrhythmias, and left ventricular stunning [