The Ultrasonography Diagnosis And Histopathologic Features Of Fibrin Sheath In Temporary Central Venous Catheter

Objective: With the development of economy and medical insurance, the patient of end-stage renal disease can have a long-term survival depending on hemodialysis. Building functional vascular access is the precondition of hemodialysis. To the patients who is waiting for the maturation of the artery-venous fistula, or couldn't establish an effective artery-venous fistula, central venous catheter becomes to their line of life. K/DOQI guide book indicates that almost 21% of end-stage renal disease patients use central venous catheter as their dialysis access. According to the statistics in 1990s, about 3 to 4 millon central venous device were established annually. Some research have already proved, that all kinds of central venous access devices, including cuffed or non-cuffed, subcutaeous embedded or peripherally inserted central catheter, have fibrin sheath enveloping the catheters. Fibrin sheath causes much attention for leading central venous catheter disfunction directly and becoming a risk factor of central venous stenosis.Fibrin sheath is a membranes-like tissue made up of a smooth muscle cell and collagen layer with overlying endothelial cells which forms around the intravascular portion of the catheter. It initiates at the point that the catheter and the vessel wall contact with each other, and usually tight connected to the vessel wall, could not easily pull out upon removel. It is reported that in dysfunctional central venous catheters, the incidence caused by fibrin sheath ranges from 1.3% in the first week after initial placement, to 75% with a mean follow-up of 98 days.The origination of fibrin sheath begins 24 hours after catheterization. It encases along the surface of the catheter, and covers its entite length within 5-7 days. Animal research reported that the incidence rate of fibrin sheath reached 100% 1 week after catheterization. As early as the middle of 20th century, the subclavian vein and internal jugular venous catheter used to infusion at the begining, there were some reports about the membrans covered the catheter surface. In the year of 1964, a French paper described the membrans at the first time. Fibrin sheath can lead to a series of complications, such as thrombosis, catheter disfunction, subsequent infection, catheter removel and pulmonary embolism etc. It impacts the function of the catheter, and is the most impotent reason that induces cathter disfunction. Abroad resrarch reported the recommended iconography diagnostic method was transcatheter venography. There was no report about the observation and diagnosis by color doppler ultrasonography. Color doppler ultrasonography is an ideal method to observe and diagnose fibrin sheath for its safty, noninvasive, cheap, multi-angle, multi-direction observation.This article aims to evaluate the iconography characteristics of fibrin sheath around deep venous catheter using color doppler ultrasonography and analysis the histopathologic features.Methods: From April 2010 to January 2011, thirty maintenance hemodialysis patients with deep venous catheter were examined by color doppler ultrasonography before pulling out of the catheter, and thirteen of them were observed again after pulling out of the catheter one month later. Pulling out of the catheter use unified standard, and using HE stain and masson stain to analysis the sheath by light microscope.Results: 28 out of 30 patients showed the development of fibrin sheath by color doppler ultrasonography, with 93.3% checking out rate. The catheter wall of 28 patints were thicken, some were sigle-membranes-like tissue., some were double-layer tubular shape. 7 of them could see conglomeration with dense echo at the puncture cite of the vein. The vein wall at the puncture cite thicken at different degree. Only 2 male patients could not observe fibrin sheath over their internal jugular vein. With the occupying of the venous cavity by the catheter , thrombus and fibrin sheath, and the vell wall thickness, the blood flow in 2 patients'internal jugular vein had autograph in different degree. 17 out of 30 patients'fibrin sheath were pulled out in the process of removing the catheter, with 56.7% pulling out rate. The fibrin sheath covered the tip and middle portion of the catheter with different thickness.13 of them were followed after pulling out of the catheter one month later. The fibrin sheath were still found at the puncture point in situ, no matter if the sheath covered the tip and middle portion of the catheter were pulled out or not.14 out of 17 samples were made into pathological slide. The result of HE stain showed, 13 out of 14 samples had the stucture of delamination, consisting of eosinophilic material, some inflammatory cells and red thrombus made of lots of red blood cells. 1 sample had loose reticulate structure, and scattered with little spindle nucleus cells, with thin and flat nucleus cells covered the surface of the sheath. The result of masson stain showed, neither the 14 samples checked out of collagen which should be stained as blue.Conclusion: Color doppler ultrasonography can observe the specific iconography characteristics, which is a kind of method that easily to handle and master in clinical to observe and diagnose fibrin sheath. It profits to maintain the function of the deep venous catheter, if we combine ultrasonography with venography in necessary. Continuous observation by color doppler ultrasonography accompany with further research of histopathologic features will make sense to make clear of the developing mechanism, the component and to find effective drug to prevent and treat fibrin sheath formation.