From the Guidelines
Patients with congestive hepatopathy have altered hemostasis, but traditional laboratory measures such as Prothrombin Time (PT) and Activated Partial Thromboplastin Time (APTT) are often misleading.
Effects on PT and APTT
- PT and APTT may be prolonged in patients with cirrhosis due to decreased plasma levels of coagulation factors and inhibitors of coagulation 1.
- However, these changes do not necessarily indicate a bleeding tendency, as both prohemostatic and antihemostatic pathways are disturbed in complex ways 1.
- Global tests of hemostasis, such as plasma-based thrombin generation tests and whole-blood viscoelastic tests, have shown that patients with cirrhosis have normal to elevated thrombin-generating capacity and near-normal whole-blood clot formation 1.
Clinical Implications
- Prolonged PT and APTT do not predict bleeding in patients with cirrhosis, and attempts to correct these abnormalities prior to procedures are not recommended 1.
- The use of fresh frozen plasma (FFP) transfusion to correct coagulopathy in patients with cirrhosis is not supported by clinical evidence 1.
- A more nuanced approach to managing hemostatic abnormalities in patients with cirrhosis is needed, taking into account the complex changes in their hemostatic system and the limitations of traditional laboratory tests 1.
From the Research
Effects of Congestive Hepatopathy on PT and APTT
- The effects of congestive hepatopathy on Prothrombin Time (PT) and Activated Partial Thromboplastin Time (APTT) are not directly addressed in the provided studies.
- However, study 2 discusses the effects of multiple mild coagulation factor deficiencies on PT and APTT, which may be relevant to liver disease.
- According to 2, single coagulation factor deficiencies predictably prolong PT and APTT at levels below 35% of normal activity.
- The study also found that when plasma samples containing 50% activity of a single factor and 100% of all other factors were prepared, the resulting mixtures had normal PT and APTT values.
- However, when two of these 50% factor-deficient plasmas were combined, the resulting PT and APTT were prolonged.
Mixing Studies for PT and APTT
- Study 3 evaluated optimal interpretation methods for APTT and PT mixing studies.
- The study found that percentage correction was the most suitable calculation method for interpreting PT mixing test results.
- For APTT mixing tests, percentage correction should be performed, and if the result indicates a factor deficiency, this should be confirmed with the subtraction III calculation.
- Study 4 proposed a new method of mixing study interpretation based on estimation of average factor level changes, which was found to be superior to other correction methods.
Other Factors Affecting PT and APTT
- Study 5 investigated the effects of hemolysis on plasma PT and APTT tests using the photo-optical method.
- The study found that hemolysis can affect PT and APTT results, with significantly shorter APTT measured in hemolyzed samples.
- Study 6 evaluated the prognostic value of PT and APTT in newly diagnosed patients with multiple myeloma.
- The study found that patients with prolonged PT or APTT had worse clinical indicators and shorter overall survival.