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

Figures

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  Figure 1. Following recording of baseline hemodynamics, cardiopulmonary bypass was initiated, aortic cross-clamping was performed with consecutive administration of the first dose of cardioplegic solution. The second dose was given after 30 min of ischemia (total ischemia time: 60 min). Aortic declamping was followed by a 60 min period of on-pump reperfusion, which included CPB weaning. After another period of 90 min of off-pump reperfusion, the animal was sacrificed. The indicated time points correspond to sampling points.

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  Figure 2. Effects of POL (red lines) and DEPOL (blue lines) on the primary outcome parameter arterial CK-MB and secondary outcome parameters. (A) There was no relevant difference between POL and DEPOL at all time points (p = 0.78). (B) Systolic left ventricular pressure was higher in POL (p = 0.01). (C) Cardiac output was comparable in both groups (p = 0.07). (D) The POL group showed markedly increased coronary flow (p = 0.29). (E) POL resulted in lower pulmonary capillary wedge pressure (p = 0.04). (F) Stroke volume was not different between POL and DEPOL (p = 0.68). On-pump reperfusion: time points 1–60 min; off-pump reperfusion: time points 90–150 min. Arithmetic or geometric means (depending on whether data were log-transformed for analysis) with 95% confidence intervals estimated by a mixed linear model that adjusts for baseline differences were used for the illustrations.

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  Figure 3. Effects of polarizing (POL, red lines) and depolarizing (DEPOL, blue lines) cardioplegic solutions on secondary outcome parameters. (A) No significant difference between POL and DEPOL in terms of coronary CK-MB at all time points (p = 0.55). (B) In the POL group, a higher requirement for noradrenaline was observed (p = 0.013). (C–F): There was no impact on heart rate (p = 0.37), APsys (p = 0.48), APdia (p = 0.90), or APmean (p = 0.72) by different cardioplegic solutions. Arithmetic or geometric means (depending on whether data were log-transformed for analysis) with 95% confidence intervals estimated using a mixed linear model that adjusts for baseline differences were used for the illustrations. On-pump reperfusion: time points from 1 to 60 min. Off-pump reperfusion: time points from 90 to 150 min. * p < 0.05.

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  Figure 4. High-energy phosphates, including phosphocreatine (PCr), adenosine triphosphate (ATP), as well as PCr/ATP ratio and energy charge were determined from freeze-clamped left ventricular biopsies obtained immediately after 150 min of reperfusion. The levels of PCr and ATP showed similar preservation across both groups (A,B). No relevant differences were observed in the PCr/ATP ratio (C) or energy charge (D). POL: polarizing cardioplegic solution; DEPOL: depolarizing cardioplegic solution.