Best Blood Sample Draw Site During Liver Transplantation

Retrograde reperfusion of renal grafts to reduce ischemic-reperfusion injury

Background

During transplantation, a kidney graft undergoes a cascade of pathological changes, referred to as ischemia-reperfusion injury (IRI), as it is incorporated into the bloodstream. Various studies have reported that retrograde reperfusion (RRP) leads to improved myocardial recovery and could reduce IRI in liver transplantation. This study investigated the effect of RRP in renal transplantation with a focus on reduction of kidney IRI.

Methods

Between December 2019 and July 2022, 15 consecutive kidney transplants were performed with retrograde venous reperfusion. To conduct a comparative study and to recruit a control group, 15 kidney transplants that had been performed in the same center by the same two surgeons were retrospectively analyzed. Differences between the two groups were considered statistically significant at P<0.05.

Results

The baseline characteristics of the two groups were statistically comparable (P>0.05). The surgical technique for kidney transplantation was the same in both groups. On the first postoperative day, polyuria was less pronounced in the RRP group (P<0.01). Serum creatinine and urea levels and estimated glomerular filtration rates on postoperative days 1, 4, 7, and 30 were lower in the RRP group (P<0.05).

Conclusions

Retrograde venous reperfusion of a kidney transplant, preceding antegrade arterial reperfusion, reduced the effects of renal parenchyma IRI. To validate the results of this study, it is necessary to conduct further studies on a larger cohort of patients with a longer follow-up period.

Effects of retrograde reperfusion on the intraoperative internal environment and hemodynamics in classic orthotopic liver transplantation

Background

To investigate the effects of retrograde reperfusion on the intraoperative internal environment and hemodynamics in classic orthotopic liver transplantation (OLT).

Methods

Thirty patients were undergone classic OLT using retrograde reperfusion in our center. Blood sampling was done at different time points including: Before blood venting via the portal vein (PV), 10 mL of blood was collected from the inferior vena cava (T₀); During retrograde reperfusion through the inferior vena cava (IVC), 10 mL of blood was collected when the volume of blood venting reached 10 mL (T₁), 100 mL (T₂), and 200 mL (T₃), respectively. 5 mL of blood was analyzed using a NOVA-f–type Blood Gas Analyzer. The remaining 5 mL was measured to determine the level of IL-1β using an enzyme-linked immunosobent assay.

Results

All operations were completed successfully, and postreperfusion syndrome (PRS) occurred in 6 patients (20%). The most notable findings were significant changes at T₁, T₂ and T₃, including pH value, PvO₂, SvO₂, BEecf, HCO₃⁻, Lac, K⁺, Ca²⁺ and IL-1β, compared with T₀ (P < 0.05). Yet their levels at T₃ were not back to the level at T₀ (P < 0.05).

Conclusion

This retrograde perfusion could eliminate some harmful metabolites inside the donor liver in time and reduce acid-base and electrolyte disorders as well as drastic hemodynamic fluctuations after recirculation during classic OLT.

Release of cytokines and hemodynamic instability during the reperfusion of a liver graft

The objectives of this prospective, observational study were (1) to determine whether a transplanted liver graft releases proinflammatory cytokines into the systemic circulation upon reperfusion and (2) to determine whether they contribute to any subsequent hemodynamic instability observed after graft reperfusion (if this release occurs). Blood samples from 17 consecutive patients undergoing liver transplantation were analyzed for cytokines, including tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), IL-2, IL-6, and IL-8. Blood samples were obtained from the radial artery, portal vein, and flush blood (a sample taken from a catheter placed above the infrahepatic inferior vena cava clamp). The amount of catecholamines necessary to maintain a mean arterial pressure between 65 and 75 mm Hg during graft reperfusion was compared with the level of cytokines. A statistical analysis was performed with the least squares method, Kendall's tau-b test, and regression analysis. We demonstrated that flush blood from the liver grafts contained a significant amount and variety of cytokines. Most of these were removed by graft irrigation. The concentration of TNF-α in samples obtained from flush blood at the end of liver irrigation was significantly higher than the concentration in samples obtained from the radial artery (P = 0.0067) or portal vein (P = 0.0003) before reperfusion. This correlated directly with the amount of catecholamines used to treat hemodynamic instability. Although there were increased levels of IL-1β, IL-2, and IL-8 in the flush blood, there was no statistically significant correlation between the levels of these cytokines and the amount of catecholamines used.