ANTITHROMBIN-III DEFICIENCY AS A RISK FACTOR FOR CATHETER-RELATED CENTRAL VEIN-THROMBOSIS IN CANCER-PATIENTS

The fibrin sleeve of venous catheters (VC) and parietal thrombi repres ent frequent and dangerous side-effects of central venous catheterizat ion (CVC), due to the risk of embolism. Reduced levels of coagulation clotting factors inhibitors (such as Antithrombin III) are known to be associated with increased thrombogenic risk. The aim of this study wa s to evaluate the role of Antithrombin III (AT III) deficiency as a ri sk factor for thrombosis in cancer patients undergoing CVC. The study groups included patients with a reduced AT III activity (< 70%, 20 con secutive patients) and with normal AT III values (> 70%, 20 randomly s elected patients), requiring a VC for chemotherapy and/or total parent eral nutrition. The study protocol included evaluation of Hb, PLTs, PT (INR), aPTT, Fibrinogen and AT III at days 0, 1, 3 and 8 after CVC an d upon VC removal. Peripheral and pullout phlebographies were performe d in all patients on catheter withdrawal. A quantitative scale was dev eloped to evaluate both VC and parietal thrombus degree in each cathet er-containing venous segment (subclavian, innominate, superior vena ca va); the sum of the mean values was defined as overall thrombus. The a verage VC dwelling time was similar in both groups. There were no sign ificant differences in Hb, PLTs, PT (INR), aPTT, Fibrinogen and in the remaining parameters of the study between the two groups. The group w ith AT III deficiency presented a higher degree of both parietal (p < 0.05) and overall thrombus (p < 0.02). Data showed a higher severity o f CVC-related thrombosis in patients with AT III deficiency than in th e control group. Further studies are needed to evaluate whether the th erapeutically-induced normalization of AT III levels can reduce the th rombosis degree.