Quantification of fibrin in blood thrombi formed in hemodialysis central venous catheters: a pilot study on 43 CVCs

PURPOSE:Fibrin deposition and thrombotic occlusion represent a serious cause of access dysfunction in hemodialysis central venous catheters (CVCs). The aim of this work was to define and apply a method for imaging and quantifying fibrin in thrombi formed into the side holes of CVCs. METHODS:Forty-three CVCs removed from a cohort of dialyzed patients were analyzed in this pilot study. Hematoxylin and eosin and a modified Carstair's staining were applied on permanent thrombus sections. Fluorescence microscopy and image analysis were performed to quantify the fibrin amount. RESULTS:Highly fluorescent areas were invariably associated with fibrin by Carstair's method. The deposition of concentric layers of fibrin and erythrocytes was easily identified by fluorescence microscopy, showing growth features of the thrombus. Fibrin amount in diabetic patients was significantly higher than that in nondiabetic patients with median (interquartile range) values of 51% (47-68%) and 44% (30-54%), respectively (p=0.032). No significant difference in fibrin content was found by grouping data according to catheter type, permanence time, insertion site and dialysis vintage. Higher variability in fibrin values was found in thrombi from CVCs removed after 1-15 days compared with 16-60 days. A trend of an increase in fibrin amount in thrombi was noted according to blood platelet count at CVC insertion. CONCLUSIONS:The analytical method presented here proved to be a rapid and effective way for quantifying fibrin content in thrombi formed on CVCs with potential application in future clinical studies.