Thrombosis associated with chronic hemodialysis vascular access by mrz53354

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									  Thrombosis associated with
 chronic hemodialysis vascular
       access: Catheters

Last literature review version 16.1: Jan. 2008

Presented by: Kitty Huang
              INTRODUCTION
   The use of tunneled catheters for vascular access for
    hemodialysis is associated with a relatively high
    incidence of complications.
   The most frequently occurring complication is
    catheter dysfunction or poor flow.
   A catheter that is not able to deliver at least 400
    mL/min should be evaluated for dysfunction
   Catheter dysfunction is progressive. If a catheter
    capable of providing a blood flow of 400 mL/min is
    only able to allow for a flow of 300 mL/min, the
    progressive pathogenic process has begun.
        EARLY CATHETER FAILURE
   Early catheter failure is defined as that which occurs
    immediately. The catheter never functioned adequately.
   Early failure are related to catheter position or technical
    problems with placement
   Improper positioning are catheter tip malorientation, tip
    malposition, and placement into the azygous vein
   Management —
       Problems that result in early catheter failure must be
        recognized and corrected at the time of catheter placement.
       Fluoroscopy is critical to this purpose, it should be
        considered mandatory for the placement of all chronic
        dialysis catheters.
    LATE CATHETER DYSFUNCTION
   It is generally the result of partial or total
    thrombosis.
   Catheter thrombosis is a common problem,
    frequently resulting in catheter loss (the
    mean patency rate ranges from 73 to 84
    days).
   The specific factors leading to thrombosis in
    an individual case are seldom obvious.
     LATE CATHETER DYSFUNCTION-
    Extrinsic catheter-related thrombosis
   Axillo-subclavian vein thrombosis
       It is uncommon, occurring in only 2 percent in a series of 101
        percutaneously inserted catheters
       Management:
            severely symptomatic patients with axillo-subclavian thrombosis
             should be treated with a five to seven day course of heparin.
            Oral anticoagulants can be started within 24 hours of the initiation
             of heparin. Warfarin should be started at a dose of 5 mg with
             subsequent doses adjusted to achieve an INR of 2.0 to 3.0.
   Mural thrombus — It forms on the wall of the vein or the
    atrium at the point of its contact with the tip of the
    catheter.
       The diagnosis is generally made with venography performed
        through the catheter. Larger mural thrombi can be detected
        by transesophageal echocardiography.
     LATE CATHETER DYSFUNCTION-
    Extrinsic catheter-related thrombosis
   Large intra-atrial thrombus — This thrombus
    presents as a mass within the right atrium.
       A thrombus of 2 cm or less is not felt to be of clinical
        importance.
       A large intra-atrial thrombus (greater than 2 cm) is a
        rare complication of a hemodialysis catheter.
       It may present as hemodialysis catheter dysfunction,
        systemic infection, pulmonary or systemic emboli, or a
        mass within the right atrium
       Treatment: catheter removal with prolonged
        anticoagulation, thrombolysis followed by catheter
        removal, simultaneous catheter removal and immediate
        surgical thrombectomy, and simple catheter removal.
     LATE CATHETER DYSFUNCTION-
    Intrinsic catheter-related thrombosis*
   Intraluminal thrombosis
       The key to prevention is adequate catheter maintenance.
            Forcibly flushing both lumens of the catheter
            Anticoagulant solution
   Catheter tip thrombosis
   Fibrin sheath thrombus*
       It generally causes catheter dysfunction weeks or months
        after catheter placement.
       This sheath is only loosely attached to the catheter. When a
        catheter is removed, angiography performed through the
        partially retracted catheter can demonstrate a "wind sock" of
        residual fibrin sleeve in approximately 40 percent of cases
TREATMENT OF LATE DEVELOPING FLOW
      PROBLEMS DUE TO INTRINSIC
               THROMBUS
 Primary treatment

       Forceful saline flush
       Intraluminal lytic enzyme
            Urokinase
            Tissue plasminogen activator (tPA)
       Infusion of lytic enzyme
   Secondary treatment: radiographic evaluation
       Catheter exchange over a guidewire
       Fibrin sheath stripping

								
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