Review article: the prothrombin time test as a measure of bleeding risk and prognosis in liver disease

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Abstract

Review article: the prothrombin time test as a measure of bleeding risk and prognosis in liver disease

A. TRIPODI11Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, IRCCS Maggiore Hospital, Mangiagalli and Regina Elena Foundation, University of Milan, Milan, Italy., S. H. CALDWELL22University of Virginia, Digestive Health Center of Excellence, GI/Hepatology Division, and the Division of Hematology and Oncology, Charlottesville, Virginia., M. HOFFMAN33Duke University Medical Center, Department of Pathology, Durham NC., J. F. TROTTER44University of Colorado Health Sciences Center, Division of Gastroenterology/Hepatology, Denver, CO. & A. J. SANYAL55Virginia Commonwealth University, Division of GI/Hepatology, Richmond, Virginia.

1Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, IRCCS Maggiore Hospital, Mangiagalli and Regina Elena Foundation, University of Milan, Milan, Italy. 2University of Virginia, Digestive Health Center of Excellence, GI/Hepatology Division, and the Division of Hematology and Oncology, Charlottesville, Virginia. 3Duke University Medical Center, Department of Pathology, Durham NC. 4University of Colorado Health Sciences Center, Division of Gastroenterology/Hepatology, Denver, CO. 5Virginia Commonwealth University, Division of GI/Hepatology, Richmond, Virginia.

Correspondence: A. Tripodi, Via Pace 9, 20122-Milan, Italy. Phone: +39 02 5503 5437. FAX: +39 02 503 20723. e-mail: armando.tripodi@...

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Abstract

Background. Prothrombin time (PT)-derived international normalized ratio (INR) is used to assess bleeding risk and prognosis in cirrhosis and to guide management of associated coagulation disturbances. Recent studies cast doubt on the validity of the assumptions that form the basis for these applications.

Aims. To review and critique the use of the PT-INR in cirrhosis.

Methods. Search of the literature.

Results. In cirrhosis, there is a decrease in both pro- and anti-coagulants. The PT-INR measures only the activity of pro-coagulants and fails to capture changes in anti-coagulants. It is therefore not surprising that the PT does not predict the bleeding risk. The PT-INR provides a robust measure of liver function but recent data showed INR inter-laboratory variability in this setting. This is not surprising as the INR was validated to normalize results for patients on vitamin-K antagonists, not for cirrhosis. This limitation was not appreciated and the INR is used to construct the MELD score to prioritize patients for liver transplantation. Reports showed that MELD is modified by the thromboplastin used for testing.

Conclusions. Alternate tests to predict bleeding risk should be developed. The potential for misuse of the PT-INR should drive the development of alternate algorithms for organ allocation.