Background and study aim: Patients with liver cirrhosis may develop serious changes of coagulation process. Protein C (PC) is synthesized in the liver and considered as the key component of an important natural anticoagulant pathway. D-dimer is a fibrin degradation product that represents an accurate marker of fibrinolytic activity.  Advances in imaging techniques have resulted in 5–27% increase in patients with liver cirrhosis being diagnosed with portal vein thrombosis (PVT). The aim of this study was to estimate the value of plasma levels of protein C and D-dimer as predictors for diagnosis of PVT in patients with liver cirrhosis.
Patients and methods: This study included one hundred cirrhotic patients who under-went abdominal ultrasound and dynamic contrast enhanced computed tomography (CT) scans. Therefore, they were classified into two groups as following: Group 1: Included twenty six patients (22 males and 4 females, mean age 53.60±7.8 years) with PVT and Group 2: Included seventy four patients (65 males and 9 females, mean age 54.96±6.5 years) without PVT as a control group. Full history taking, complete physical examinations and laboratory investigations including liver function tests, complete blood count, prothrombin time (PT), activated partial thromboplastin time (aPTT), International Normalizing Ratio (INR) and determination the levels of plasma protein C and D-dimer were done for all cirrhotic patients.
Results: The levels of D-dimer were significantly higher in cirrhotic patients with PVT than in those patients without PVT, while the level of protein C were significantly lower in cirrhotic patients with PVT than the control group. Also, D-dimer was significantly increased from Child-Pugh class A to C, while PC was significantly progressively decreased. D-dimer cut-off values above 530 ng/L provided high sensitivity and negative predictive value (92.3% and 95.7%, respectively). Also, PC cut-off values below 71.6 % had a high sensitivity and negative predictive value (96.2 and 96.9%, respectively).
Conclusion: PVT formation in liver cirrhosis is closely associated with decreased plasma levels of PC, and increased D-dimer. So, they are considered risk factors in PVT formation in patients with liver cirrhosis. So, estimation of plasma levels of protein C and D-dimer are important for early detection of PVT in patients with liver cirrhosis.