Integrating Dialysis in Ex Situ Machine Perfusion: A Systematic Review and Meta-Analysis of Outcomes

Ex situ machine perfusion (EVMP) leads to the accumulation of metabolites and electrolytes in the perfusate. This review aimed to examine the impact of dialysis on biochemical and functional parameters during EVMP.

A systematic review was conducted per PRISMA guidelines. Studies integrating dialysis in lungs, liver, pancreas, and heart EVMP, either in large animals or humans, were included. Biochemical and metabolic parameters, organ weight, inflammatory markers, and organ-specific outcomes were extracted. Meta-analyses and longitudinal regression were conducted.

Nineteen studies were included. Dialysis maintained sodium (p = 0.17), potassium (p = 0.75), lactate concentrations (p = 0.3), and pH (p = 0.1). A significant decrease was seen in chloride concentration (p < 0.01), while calcium levels increased significantly over time in the dialysis group (p < 0.001). Interleukin 6 was elevated in dialysis relative to the controls during porcine lung perfusion (p < 0.05) and trended toward significance in humans (p = 0.08). During heart perfusion, the dialysis group exhibited higher cardiac contractility, expressed as a percentage of baseline (71.2% ± 7.7 vs. 55.3% ± 8.2, p < 0.05). During liver perfusion, bile production increased significantly from baseline (β = +1.85 IU/L/h, p < 0.001). Lung compliance was stable in the dialysis (β = -2.34 mL/H₂O/h, p = 0.36) and control groups (β = +0.12 mL/H₂O/h, p = 0.27).

Dialysis maintained biochemical homeostasis during EVMP. Significant functional benefits were seen in cardiac EVMP and should be investigated in other organs, including appropriate control groups.