Causes of High Venous Pressure in Hemodialysis Catheters

Primary Causes of High Venous Pressure

The American Journal of Kidney Diseases reports that thrombotic occlusion is the most common cause of high venous pressure (>250 mmHg) in a hemodialysis catheter, which can occur as intraluminal thrombus, catheter tip thrombus, fibrin sheath formation, or fibrin tail development 1, 2, 3
Intraluminal thrombus can cause partial or complete occlusion within the lumen of the catheter 3
Catheter tip thrombus can occur, especially in catheters with side holes, where thrombus may act like a "ball valve" 3
Fibrin sheath formation can occur, where fibrin adheres to the external surface of the catheter with thrombus trapped between the sheath and catheter tip 3
Fibrin tail development can occur, where fibrin adheres to the catheter end, creating a "ball valve" effect 3
Catheter malposition can cause high venous pressure, and is affected by patient position 3, 4
Kinking of the catheter can cause obstruction to flow 4
Catheter damage can occur, to external or internal portions 5
Compression of the catheter between anatomical structures (pinch-off syndrome) can cause high venous pressure 5

Venous pressure >250 mmHg is a clear sign of catheter dysfunction, according to the American Journal of Kidney Diseases 1, 2
Blood pump flow rates <300 mL/min can indicate catheter dysfunction 1, 2
Arterial pressure <–250 mm Hg can indicate catheter dysfunction 1
Conductance <1.2 (ratio of blood pump flow to absolute value of prepump pressure) can indicate catheter dysfunction 1
Progressive decrease in URR <65% (or Kt/V <1.2) can indicate catheter dysfunction 1
Inability to aspirate blood freely can be a late manifestation of catheter dysfunction 1
Frequent pressure alarms not responsive to patient repositioning or catheter flushing can indicate catheter dysfunction 1

For new catheters (<2 weeks old), the American Journal of Kidney Diseases recommends checking for mechanical issues, such as kinks in the catheter, and assessing if the Trendelenburg position is needed to achieve adequate flow 3
For older catheters (>2 weeks old), thrombotic occlusion is suspected as the primary cause, and thrombolytic therapy may be implemented 3, 6
The use of intraluminal interdialytic thrombolytic lock protocol between dialysis treatments can help to restore catheter function 6
Tissue plasminogen activator (tPA) can be used for clots 3

Proper catheter placement initially, with the tip positioned in the mid-right atrium, can help to prevent catheter dysfunction, according to the American Journal of Kidney Diseases 3
The use of appropriate anticoagulant locking solutions between dialysis sessions can help to prevent thrombosis 3
Avoiding the use of the catheter for purposes other than dialysis (blood draws, contrast media) can help to prevent catheter damage 5
Implementing proper catheter care protocols can help to prevent damage to external portions 5
Regular monitoring of catheter performance can help to detect early signs of dysfunction 1

Early detection and treatment of catheter dysfunction is crucial, as a dysfunctional catheter is easier to salvage than a nonfunctional one, according to the American Journal of Kidney Diseases 1, 2
Catheter dysfunction can lead to 17-33% of untimely catheter removals 1, 2
Thrombosis occurs in 30-40% of patients with catheter access 1, 2
Inadequate blood flow can result in underdialysis and negatively impact patient outcomes 1, 7

La disfunción del catéter de diálisis se clasifica en tres categorías principales según las guías KDOQI 2019: complicaciones trombóticas relacionadas con el flujo, complicaciones no trombóticas relacionadas con el flujo, y complicaciones infecciosas 8
Un catéter se considera disfuncional cuando no puede alcanzar un flujo sanguíneo de 300 mL/min en un catéter que previamente podía entregar más de 350 mL/min a una presión de prepompa de -250 torr 9, 10

Cualquier infección que involucre el acceso vascular y resulte en signos y síntomas infecciosos clínicamente importantes 8
La infección del sitio de salida debe tratarse con antibióticos tópicos y/o orales, asegurando cuidado local apropiado del sitio de salida; generalmente no es necesario remover el catéter 9, 10

Un catéter disfuncional (flujo sanguíneo <300 mL/min) durante 2 tratamientos consecutivos debe tratarse en la unidad de hemodiálisis usando un protocolo de bloqueo trombolítico intraluminal interdialítico entre 2 tratamientos de diálisis (35 a 69 horas) 9, 10
La terapia trombolítica restaura la permeabilidad en 67% con una dosis y 88% con dos dosis 9, 10

Reposicionamiento del catéter 9, 10
Angioplastia del vaso 9, 10
Reemplazo del catéter malposicionado sobre guía 9, 10
Infusión lítica de dosis alta para trombo oclusivo (ej., aurícula derecha) o vaina de fibrina 9, 10
Uso de cepillo especial para remover trombo de las luces del catéter 9, 10