Assessment Tools in Ex Situ Heart Perfusion: An Evaluation in a Pig Model

Background: Ex situ heart perfusion (ESHP) enables the resuscitation and assessment of donor hearts. Therefore, a comprehensive analysis of myocardial function and metabolism is crucial. Currently, the only used assessment tool for quality control is sequential lactate measurement from the perfusate. The aim of this study was to investigate new assessment tools in ESHP.

Method: Twelve German domestic pigs were used as heart and blood donors. “Donation after brain death” (DBD) (n = 6) and “donation after circulatory death” (DCD) (n = 6) were simulated and 6 hours of normothermic ESHP was performed. Analyses were performed at 1 (T1), 3 (T2) and 6 (T3) hours of perfusion. Different assessment tools were used to analyze functional status (left ventricular pressure balloon [LVPB], visual cardiac score [VCS]) and myocardial damage and metabolic in the perfusate (lactate, myoglobin, high-sensitive [hs] troponin t). Additionally, microdialysis catheters were inserted in the myocardium of the left ventricle. Semi-continuous perfusate samples were taken every 10 minutes. Subsequently, lactate, pyruvate, and glycerol were analyzed.

Results: Parameters of myocardial damage increased in both groups and were significantly higher in the DCD group: myoglobin (T1: DCD 1,154 ± 444.7 vs. DBD 385.2 ± 113.8 µg/L, p = 0.011; T3: DCD 2,002 ± 571.4 vs. DBD 652 ± 117.2 µg/L, p = 0.003), hs troponin T (T1: DCD 44,796 ± 46,581 vs. DBD 12,229 ± 6,447 ng/L, p = 0.159; T3: DCD 446,742 ± 315,830 vs. DBD 102,496 ± 33,448 ng/L, p = 0.044). Functional assessment revealed a decline during ESHP in both groups. LVPB did not differ between the groups (T1: DCD 160 ± 97 vs. DBD 204 ± 83 mm Hg, p = 0.354; T3: DCD 66 ± 38 vs. DBD 104 ± 40 mm Hg, p = 0.250), whereas VAS was significantly lower in DCD group (T1: DCD 7.3 ± 0.8 vs. DBD 7.8 ± 1.2, p = 0.490; T3: DCD 2.7 ± 1.0 vs. DBD 5.8 ± 1.5, p = 0.002). Interstitial levels of lactate, pyruvate, and glycerol did not differ at baseline between the two groups. Pyruvate increased significantly faster in the DCD group once ESHP was implemented (20 min: DCD 162.8 ± 124.4 µmol/L vs. DBD 26.41 ± 23.97 µmol/L, p = 0.04). Glycerol was stable during ESHP in the DBD group but was significantly higher in the DCD group with a rapid increase directly after reperfusion (20 min: DCD 783.79 ± 280.02 µmol/L vs. DBD 105 µmol/L ± 71.73, p < 0.001).

Conclusion: Additional assessment tools in ESHP are urgently necessary. Biomarker and microdialysis are both feasible and able to detect metabolic and functional.

Publication History

Article published online:
28 January 2023