Prediction of bleeding in cirrhosis patients: Is the forecast any clearer?
Authors: Nicolas M. Intagliata, Stephen H. Caldwell, Robert J. Porte, Ton Lisman
Journal: Hepatology (2015)

Potential conflict of interest: Dr. Caldwell consults for Vital Therapies. Dr. Intagliata consults for Vital Therapies. Author names in bold designate shared co‐first authorship. To the Editor: "Prediction is very difficult, especially if it is about the future." Niels Bohr We read with great interest the article by De Pietri and colleagues evaluating the use of viscoelastic testing (thromboelastography [TEG]) as a guide to prophylactic blood product transfusion prior to procedures in patients with cirrhosis.1 This provocative study is timely as the dogma of coagulation in cirrhosis has undergone significant revision in the last several years. Evidence clearly indicates that conventional coagulation tests such as prothrombin time/international normalized ratio do not reliably predict bleeding in patients with cirrhosis.2 The authors should be commended for approaching such a clinically important and relevant topic with such rigor. Prophylactic transfusion to prevent bleeding before a procedure has been a common practice in patients with liver disease yet lacks supportive evidence. In fact, liver transplantation can be performed without the requirement of any blood products in some patients, despite prolonged conventional coagulation tests.5 The authors demonstrated that using TEG parameters resulted in significantly fewer transfusions. This is a clinically very important result. However, the question remains whether a transfusion prompt based on TEG results is comparable to that commonly used for conventional coagulations tests, such as prothrombin time/international normalized ratio. In other words, did TEG testing simply result in a higher transfusion threshold compared to conventional coagulation tests, and does that explain this observed benefit? Moreover, it must also be noted that use of TEG parameters presupposes the test's ability to accurately define risk and guide intervention. To our knowledge, TEG has never been shown to predict bleeding in patients with cirrhosis. The primary clinical use of viscoelastic testing in cirrhosis has been in patients undergoing liver transplantation as a point of care guide to intraoperative transfusion therapy. The question thus remains, are prophylactic transfusions, irrespective of "normal" or "abnormal" preprocedural testing, necessary at all for most procedures? Recent advances in understanding the coagulopathy of liver disease raise the question of the need for a third cohort in which no prophylactic transfusions of platelets or fresh frozen plasma are given prior to procedures. An alternative approach to patients undergoing low‐risk to moderate‐risk procedures may be to consider "rescue" therapy in the event of bleeding, rather than prophylactic therapy aimed at an unproven predictive marker. This approach would certainly minimize the use of unnecessary transfusion even further and is well supported by experience in liver transplant. TEG, in this case, represents a reference point to calibrate prophylactic transfusion goals that ipso facto do not change the inherent risk of bleeding. While the use of TEG reduced transfusion overall, it is not clear that reliance on this measure, without a proven ability to predict bleeding in cirrhosis, gains us any further insight into an authentic need for prophylactic transfusions. The one significant bleeding event in this study was hemoperitoneum after paracentesis. As the authors note, it is likely this bleeding would have occurred irrespective of transfusion because of a mechanical injury to a blood vessel. We commend the authors for efforts at a more rational and "physiologic" approach to determining bleeding risk in this challenging population. TEG may help to decrease the practice of unnecessary and harmful transfusion prophylaxis in this population; however, we question if the widespread use of this testing would gain us any significant predictive advantage over the current clinically available tests. Future studies should include patients who do not receive prophylactic transfusions, with a carefully constructed rescue plan should bleeding occur.