Normothermic Crystalloid Polarizing Cardioplegia Improves Systolic and Diastolic Function in a Porcine Model of Cardiopulmonary Bypass

Background/Objectives: Previously, we showed that blood-based polarizing cardioplegia exerted beneficial cardioprotection during hypothermic ischemia; however, these positive effects of blood-based polarizing cardioplegia were reduced during normothermic ischemia compared to blood-based hyperkalemic...

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Main Authors: David Santer, Stefan Heber, Anne-Margarethe Kramer, Judith Radloff, Katharina Heissl, Attila Kiss, David J. Chambers, Seth Hallström, Bruno K. Podesser
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Biomedicines
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Online Access:https://www.mdpi.com/2227-9059/13/1/70
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Summary:Background/Objectives: Previously, we showed that blood-based polarizing cardioplegia exerted beneficial cardioprotection during hypothermic ischemia; however, these positive effects of blood-based polarizing cardioplegia were reduced during normothermic ischemia compared to blood-based hyperkalemic (depolarizing) cardioplegia. This study compares crystalloid polarizing cardioplegia to crystalloid depolarizing cardioplegia in a normothermic porcine model of cardiopulmonary bypass; Methods: Twelve pigs were randomized to receive either normothermic polarizing (<i>n</i> = 7) or depolarizing (<i>n</i> = 5) crystalloid cardioplegia. After the initiation of cardiopulmonary bypass, normothermic arrest (34 °C, 60 min) was followed by 60 min of on-pump and 90 min of off-pump reperfusion. Myocardial injury (arterial CK-MB), hemodynamic function, and the energy status of the hearts were measured; Results: The arterial release of CK-MB was comparable between groups (<i>p</i> = 0.78) during reperfusion. During 150 min of reperfusion, systolic left ventricular pressure (<i>p</i> = 0.01) and coronary flow (<i>p</i> = 0.009) were increased, and wedge pressure (<i>p</i> = 0.04) was decreased in the polarized group. Further hemodynamic parameters (cardiac output, stroke volume) and high-energy phosphate levels were similar between groups. The requirement for noradrenaline administration during reperfusion was significantly higher (<i>p</i> = 0.013) in the polarized group; Conclusions: Under normothermic conditions and despite a similar increase in levels of cardiac CK-MB, crystalloid polarizing cardioplegia protected systolic and diastolic cardiac function after 60 min of cardiac arrest. These results suggest beneficial effects for polarizing cardioplegia; clinical studies are required to confirm these effects.
ISSN:2227-9059