Routine Measurement of Endogenous Thrombin Potential (ETP) To Assess Hemostatic Function in Patients with Liver Cirrhosis.

The maintenance of hemostasis through the production of most of the coagulation proteins is a basic liver function. In patients with cirrhosis of the liver the decrease in these proteins is one of the contributory factors to an increased bleeding tendency. Normally the hemostatic capacity of the liver is measured through routine clotting tests as the activated Partial Thromboplastin Time (aPTT) and Prothrombin Time (PT). In the Child classification for liver cirrhosis the coagulation as expressed by the PT is one of the determinants.

Recently a test has become available which will make it possible to routinely measure the endogenous thrombin generation potential (ETP) which may be a better alternative. In this test according to the method first described by Hemker (1993) thrombin generation is continuously measured by use of a chromogenic substrate. Results are calculated as area under the curve and as a percentage of normal.

We analysed 110 patients with liver cirrhosis classified according to the Child classification, 79 patients with stage A, 19 stage B and 12 stage C, without known pre-existing coagulation abnormalities like inherited bleeding disorders, or anticoagulant drugs. In these patients ETP, APTT, PT/INR, FV, FVII and FXI were measured. We used a fully automated assay for the determination of the endogenous thrombin potential (ETP) on the BCS® System (both Dade Behring, Marburg, Germany).

The results for the mean PT were 81% (CI₉₅ 77 - 85) for Child A patients, 53% (CI₉₅ 44 - 63) for Child B, and 41% (CI₉₅ 33 - 50) for Child C. For the mean INR the results were 1.11 (CI₉₅ 1.08 - 1.14) for Child A patients, 1.65 (CI₉₅ 1.22 - 2.08) for Child B, and 1.82 (CI₉₅ 1.34 - 2.31) for Child C. The results for the mean normalized ETP were 0.87 (CI₉₅ 0.84 - 0.90) for Child A patients, 0.78 (CI₉₅ 0.68 - 0.88) for Child B, and 0.58 (CI₉₅ 0.51 - 0.64) for Child C (p<0.001). While the normalized ETP correlated well with both PT and INR for Child B (P<0.05) and C (p<0.01), there were significant differences within the child A patients where no significant correlation could be identified (Pearson correlation 0.203, R²=0.04, p=0.075.

We conclude that the fully automated assay for the determination of the endogenous thrombin potential (ETP) on the BCS® System (both Dade Behring, Marburg, Germany) is a potentially interesting test to measure the coagulation abilities in patients with liver cirrhosis which in the future may supersede the PT/INR in classification systems for hepatic disease.