Warm Calafiore Blood Cardioplegia Offers Better Myocardial Protection than Cold Cardioplexol Crystalloid Cardioplegia

Background: Clinical studies indicate encouraging cardioprotective potential of a new crystalloid cardioplegia (“Cardioplexol”) for short cross-clamp durations. We investigated its cardioprotective capacity in an experimental setting during 90 minutes of ischemia and compared it to warm blood cardioplegia (“Calafiore”).

Method: Twenty-two rat hearts were isolated and inserted into a blood perfused pressure controlled Langendorff apparatus. After a stabilization period, cardiac arrest (90 minutes) was induced either by intermittent Cardioplexol (CP) or Calafiore (Cala) administration. During 90 minutes of reperfusion, cardiac function and metabolism were evaluated and troponin I levels were measured. At the end of reperfusion, hearts were fixed and ultrastructural integrity was examined electron-microscopically.

Results: Baseline values (BL) of left ventricular developed pressure (LVDP), coronary flow (CF), and heart rate (HR) were similar in both groups (CP: LVDP 82.8 ± 25.0 mm Hg; CF 3.7 ± 0.5 mL/min; HR 211 ± 40 mL/min versus Cala: LVDP 86.8 ± 21.6 mm Hg; CF 4.0 ± 1.3 mL/min; HR 265 ± 66/min). Hearts exposed to Cala recovered significantly better during reperfusion than hearts after CP administration (LVDP: 22% vs. 48% of BL, p = 0.0014; CF: 24% vs. 53% of BL, p = 0.0019). During ischemia, ischemic contractures were seen in CP group starting after 38 minutes of ischemia, while no rise of diastolic pressure appeared under Cala. Accordingly, troponin I levels at the end of reperfusion were significantly higher in CP group (609.13 ± 97.21 ng/mL vs. 35.68 ± 25.89 ng/mL, p = 0.0006). Ultrastructural integrity was inferior under CP compared with Cala. Consistently, myocardial tissue developed more pronounced myocardial edema under CP administration (cellular edema index (CEI): 0.70 ± 0.063 vs. 0.61 ± 0.043, p = 0.333). Accordingly, mitochondrial integrity declined when using CP compared with Cala (volume to surface ratio [VS/ratio]: 0.16 ± 0.020 µm vs. 0.12 ± 0.002 µm, p = 0.333).

Conclusion: Calafiore cardioplegia protects the myocardium from ischemia/reperfusion related damages after 90 minutes of ischemia under experimental conditions significantly better than Cardioplexol.

Publication History

Article published online:
28 January 2023