Hemodialysis thrombosis

Thrombosis associated with hemodialysis most commonly occurs in patients with venous catheter access for dialysis and is a common cause of catheter failure. However, thrombosis can occur in synthetic grafts and less frequently in AV fistulas. 

Nonpharmacologic management of thrombosis in a hemodialysis catheter involves saline flushes. Smaller clots may be managed by balloon angioplasty to mechanically open the catheter. In severe cases in whom clots cannot be removed by either mechanical or pharmacologic therapy, the catheter may require replacement. 

It is believed that heparin acts by neutralizing a number of active blood coagulation factors, thus disrupting the transformation of prothrombin into thrombin. Heparin is used to prevent thrombo-formation in myocardial infarctions, thrombosis, and embolism, for maintaining liquid conditions in the blood in artificial blood drcnlation and hemodialysis. Synonyms of this drug are arteven, hepalen, leparan, Uquemin, panheprin, vetren, and many others. 

Unlabeled Uses Diabeticneuropathy gangrene, hemodialysis shunt thrombosis, septic shock, sickle cell syndrome, vascular impotence... 

Recombinant human erythropoietin (rHuEpo) may increase the risk of thrombosis (201). It has been reported that patients with carcinoma of the cervix who received chemotherapy and rHuEpo have an increased risk of symptomatic venous thrombosis (201). In clinical trials where the maintenance hematocrit was 3% on PROCRIT clotting of the arteriovenous shunts occurred at an annual rate of about 0.25 events per patient per year. However, other thrombotic conditions such as cerebrovascular events, transient ischemic attacks, myocardial infarction, or pulmonary embolism occurred at a rate of 0,04 events per patient per year (202). In a separate study of I, I I I untreated patients on hemodialysis, clotting of arteriovenous shunts occurred at a rate of 0.5 events per patient per year. In patients with chronic renal failure on hemodialysis who also had congestive heart failure, ischemic heart disease and venous thrombosis were increased in patients who were treated with PROCRIT targeted to a hematocrit level of 42 3% compared to those targeted to 30 3% (202). It has also been reported... 

Harter HR, Burch JW, MajerusPW, Stanford N, DelmezJA, Anderson CB, WeertsCA Preventicm of thrombosis in patients on hemodialysis by low-dose aspirin. New Eng. J. Med. 301 577, 1979... 

Central venous catheters are reluctantly used as blood access for hemodialysis because of safety concerns and frequent complications, for example sepsis, thrombosis, and vessel stenosis. Nevertheless, 20% or more of all patients rely on atrial catheters for chronic dialysis because of lack of other access. Potentially fatal risks related to central venous catheters include air embolism (1), severe blood loss (2), and electric shock (3). These specific risks have been substantially eliminated by the inherent design and implantation of Dialock (Biolink Corporation, USA). Dialock is a subcutaneous device consisting of a titanium housing with two passages with integrated valves connected to two silicone catheters. The system is implanted subcutaneously below the clavicle. The tips of the catheters are placed in the right atrium. The port is accessed percutaneously with needle cannulas. 

Vascular access thrombosis has been reported in up to 26% of patients treated with epoetin alfa (3,34,38). Most of the failures occurred in poljdetrafluoroethylene grafts. There was no comparison with patients not treated with epoetin. It has been suggested that the increased risk of extracorporeal circuit clotting and the higher heparin requirements during hemodialysis may not be due to a hypercoagulable state, but rather to an increase in erythrocyte mass and consequently in whole blood viscosity (66). 

With double-lumen intravenous catheters for acute hemodialysis, hemperfusion, and plasma exchange, the most common complications are bleeding, hematomas, catheter failure, risk of infection, central vein thrombosis and stenoses, and rarely, air embohsm. Femoral placement is the site associated with the fewest non-in-fectious comphcations [16]. Comphcations of treatment will be discussed below. 

Due to fewer complication and longer survival rates, the native arteriovenous fistula is the preferred access for hemodialysis. Venous catheters are plagued by complications such as infection and thrombosis and often deliver relatively poor blood flow rates. 

A deficiency in delivered hemodialysis therapy may be related to patient compliance with the dialysis prescription (ending dialysis early). Other causes for a low Kt/V include low blood flow rates due to access stenosis or thrombosis, or due to the use of catheters. Adequate dialysis may not be achieved in some patients despite compliance and sufficient blood flow. Eor these patients there are really only two options to increase urea clearance use a larger membrane or increase the treatment time. 

Beathard GA. Thrombosis associated with chronic hemodialysis vascular access Catheters. In Rose BD, ed. UpToDate. Wellesley, UpToDate, 2003. 

Eyrich H, Walton T, Macon EJ, Howe A. Alteplase versus urokinase in restoring blood flow in hemodialysis-catheter thrombosis. Am J Heath Syst Pharm 2002 59 1437-1440. 

The anatomic location for temporary central venous catheter (CVC) insertion and placement can be dictated by certain patient or disease restrictions, but the most common sites are the internal jugular vein (neck), the femoral vein (groin), and the subclavian position (upper chest). The internal jugular approach is the first choice for placement of a hemodialysis CVC, while femoral placement is favored when rapid insertion is essential (Canaud et al., 2000). Subclavian vein access has fallen from favor because of a higher incidence of thrombosis and stenosis associated with this site, which can ultimately prevent use of the veins in the downstream vascular tree for high-flow applications such as dialysis (Cimochowski et al., 1990 Schillinger et al., 1991). 

Infection and thrombosis are common across a variety of catheter designs and applications, while other complications arise as a result of the particular nature of the therapy being administered, such as recirculation in hemodialysis. Clatheter malfunction and related morbidity and mortality represent an area where significant strides are currently being made. 

Torosian MH, Meranze S, McLean G, Mullen JL (1986) Central venous access with occlusive superior central venous thrombosis. Ann Surg 203 30-33 Trerotola SO, Johnson MS, Harris VJ, Shah H, Ambrosius WT, McKusky MA, Kraus MA (1997) Outcome of tunneled hemodialysis catheters placed via the right internal jugular vein by interventional radiologists. Radiology 203 489-495... 

In patients with CKD, preservation of the integrity of peripheral and central veins is of vital importance for future hemodialysis access. Avoid i.v. infusion or vein puncture in the forearm and upper arm veins at both arms whenever possible. Insertion of venous access devices carries the risk to injure the veins and thereby incite phlebitis, sclerosis, stenosis or thrombosis and has to be avoided. Whenever a central venous catheter is needed, catheterization of the internal jugular or femoral vein is always preferred. Use of subclavian vein should be... 

Many physicians prescribe anticoagulants and antiplatelet medications to prevent thromboembolic events and access thrombosis in dialysis patients despite limited evidence of their efficacy in this population. Chan et al. [54] concluded that warfarin, aspirin, or clopidogrel prescription is associated with higher mortality among hemodialysis patients [54]. 

Kaufman JS, O Connor TZ, Zhang JH, et al Veterans Affairs Cooperative Study Group on Hemodialysis Access Graft Thrombosis randomized controlled trial of clopidogrel plus aspirin to prevent hemodialysis access graft thrombosis. J Am Soc Nephrol 2003 14 2313-2321. 

Beathard GA Thrombosis Associated with Chronic Hemodialysis Vascular Access Catheters. UpToDate Topic 1906, version 3.0. 2014. 

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