The specific method and ease of catheter insertion, as well as catheter size, flexibility, position, material composition, and duration of catheter use can influence the degree of vessel trauma. Catheters with left-sided placement and with malpositioned catheter tips pose a high risk for thrombus development. Polyvinylchloride and polyethylene catheters are more thrombogenic than the newer polyurethane and silicone catheters. Because of their rigid construction and relatively high displacement of blood flow, larger-diameter catheters are more likely to cause trauma to the vessel or obstruct flow than catheters of smaller diameter. The vast majority of thrombi related to central venous catheters develop without symptoms.
Warning signs are insidious but can be recognized by experienced clinicians.
As the thrombus begins to form, the catheter may seem sluggish or otherwise problematic. As thrombus formation progresses, infusion pump alarms may sound frequently or visible clots may appear on the exterior portion of the catheter. The diagnosis of catheter-related thrombosis may be based solely on symptoms or can be confirmed with the aid of imaging techniques. When a central venous catheter becomes occluded, the ultimate goal is to restore patency in a timely and cost-effective manner with minimal risk to the patient. In many cases, catheter salvage is preferred over catheter replacement for several reasons.