Background: Fibrinolytic activation with subsequent inhibition is termed fibrinolysis shutdown (SD). SD has recently been interchanged with hypofibrinolysis, which is inaccurate. Hypofibrinolysis represents a lack of fibrinolytic activation. When the native liver is removed from the patient(anhepatic) during liver transplantation tissue plasminogen activator cannot be systemically cleared and provides the ideal human model to differentiate these phenotypes. We hypothesize that a population of liver transplant patients fail to generate a fibrinolytic response during the anheptic phase of surgery and represent a hypofibrinolytic phenotype, which is distinct from patients that generate a fibrinolytic response with subsequent inhibition following graft reperfusion representing SD.

Aims: Define the fibrinolytic trends in liver transplant patients that develop fibrinolytic shutdown versus hypofibrinolysis and contrast blood product utilization.

Methods: Liver transplant patients had serial blood draws before surgical incision through post-operative day-1. Samples were analyzed with thrombelastography. Patients were dichotomized based on the lysis at 30 minutes (LY30). LY30 > 3% defined fibrinolytic activation (based on the existing literature) vs hypofibrinolysis (LY30 < 3%). Groups were contrasted on temporal changes in LY30 and transfusion requirements.

Results: Hypofibrinolysis was identified in 43% of 98 transplant patients analyzed. Hypofibrinolytic patients had a stable LY30 for the duration of surgery, whereas all of the patients with fibrinolytic activation (figure) had subsequent shutdown of fibrinolytic activity following graft reperfusion, which persisting through post-operative day-1. Blood product utilization was similar with the exception of the anhepatic phase, in which the SD group were transfused more red blood cell units(3 vs 2 units P=0.030).

Conclusions: Despite liver transplant patients having low fibrinolytic activity at the start of surgery and the following day, two distinct fibrinolytic changes occur during surgery. These data demonstrate that fibrinolysis shutdown and hypofibrinolysis are not interchangeable terms and their impact on patient outcomes warrants ongoing investigation.

[Fibrinolytic Changes in Liver Transplant Recipients]

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ISTH Congress Abstracts - https://abstracts.isth.org/abstract/low-fibrinolytic-activity-following-ischemia-reperfusion-is-not-a-single-etiology-fibrinolysis-shutdown-versus-hypofibrinolysis/