![]() ![]() t-PA (2 mg) restored catheter function more reliably and dissolved thrombi faster than twice the “standard” dose of urokinase.Ī further comparison of alteplase with urokinase in re-establishing adequate blood flow through partially or completely occluded vascular catheters was performed by Zacharias et al in 30 patients using a 30- minute push protocol to administer thrombolytics. Radiographic contrast injection showed seven catheters randomised to urokinase had complete resolution of the thrombus, compared with 17 randomised to r-tPA (p=0.042). Thirteen of 22 catheters randomised to urokinase had their full function restored compared with 25 of 28 catheters randomised to r-tPA (p=0.01). A second dose was allowed if catheter function was not restored with the first injection. In another study using the now withdrawn urokinase in the USA, Haire et al randomised 50 patients with dysfunctional central venous catheters to be injected with either 2mg r-tPA or 10,000u urokinase and allowed to dwell for two hours. The majority of patients in both treatment groups did not require further interventions. However, the percentage of functioning catheters at a subsequent haemodialysis session did not significantly differ between groups (p=0.08). Patients with alteplase-treated catheters were twice as likely to achieve haemodialysis blood flow rates of >300ml/min (p=0.01) and were more likely to complete haemodialysis during that session (93% versus 70%, p=0.02). Both thrombolytic agents significantly increased the haemodialysis blood flow rates. It presents either as a low flow rate on dialysis (300ml/min, maintained for at least 30 minutes during the dialysis session. ![]() Thrombosis is usually intrinsic to the catheter, although extrinsic obstruction due to fibrin sheath formation may be more common than acknowledged. Obstruction with a loss of ability to draw back or infuse is thought to occur in up to 28% of central catheters and is a frequent source of delayed dialysis and admission to hospital, and has an economic cost. Preventing thrombosis or managing it once established is crucial if haemodialysis activity is to be maintained. ![]() Short-term catheters usually have a simple design and the lumen volume is approximately 1 cm3 each, whereas the lumina of long-term catheters are 1.6–1.9cm3 in volume.īoth types of catheter are at high risk of luminal thrombosis. Generally, both types of catheter have double lumina, one to remove blood and the other to return the dialysed blood. ![]() The long-term dialysis catheters, which are of larger diameter, usually 14Fr, are tunnelled under the skin, have a Dacron cuff attached to allow the catheter to embed, thus becoming fixed in the subcutaneous tissue to prevent dislodgement and reduce infection tracking up from the catheter exit site. Short-term catheters are 11–12Fr in diameter and are placed in emergency situations when dialysis is needed immediately and they can be quickly removed or exchanged. Ideally, dialysis catheters should be avoided or used only for a limited short period by timely creation of arteriovenous fistulae.ĭialysis catheters are of two types – short-term, or “temporary”, catheters and long-term catheters. Unfortunately, they are often used for chronic haemodialysis, although associated with significant complications, particularly thrombosis and infection. The Royal Liverpool, University Hospital, Liverpool UKĬentral venous catheters provide vascular access for emergency haemodialysis. Thrombolytic agents are effective in restoring flow in occluded dialysis cathetersĬonsultant Transplant and Vascular Surgeon Teaser Central venous catheters that provide vascular access for haemodialysis are at high risk of luminal thrombosis. ![]()
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