Impact of cytokine release on ventricular function after hepatic reperfusion: a prospective observational echocardiographic study with tissue Doppler imaging

BACKGROUND

Postreperfusion syndrome and haemodynamic instability are predictors for poor outcome after liver transplantation. Cytokine release has been claimed to be responsible for postreperfusion syndrome. However, the underlying pathophysiologic mechanism is not clarified. The aim of this prospective observational study was to correlate cardiac performance (measured by transoesophageal echocardiography (TEE), Doppler and Tissue Doppler Imaging (TDI)) to plasmatic cytokines: IL-6, IL-8, CXCL1, TGF-β and CD40L at 5 different time points during liver transplantation.

METHODS

Seventeen consecutive patients scheduled for orthotopic liver transplantation, age 18 to 75 years without contraindication for transoesophageal echocardiography were included. Patients were monitored with TEE and TDI. Systolic and diastolic cardiac function, MAP, MPAP, CVP, PCWP, CO and blood samples for cytokine assays were recorded or collected after induction, 15 min after vena cava inferior clamping, 2 to 5 min after reperfusion, 60 min after reperfusion and at the end of surgery.

RESULTS

Mean arterial pressure and catecholamine requirements remained unchanged, MPAP, CVP and CO increased, SVR decreased after unclamping. Postreperfusion syndrome did not develop. The haemodynamic parameters and the variations of TEE parameters were consistent with the volume load changes during clamping and declamping and did not reveal systolic or diastolic cardiac dysfunction. All cytokines, except TGF-β, increased.

CONCLUSION

These findings suggest, that significant cytokine release during liver transplantation is not necessarily coincident with haemodynamic instability and impaired cardiac function.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00547924.

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.