Catheter thrombosis.

Catheter malfunction due to poor flow is a common problem. When it occurs early, the cause is generally technical. Late occurrences are most often related to thrombus formation. Several types of thrombus may be seen, differing by location and supposed mechanism of formation. The most common offender, however, is the fibrin sheath thrombus. Prevention of catheter malfunction is an endeavor that continues to beg many questions. Catheter malfunction should be treated early to avoid inadequate dialysis. In the past, urokinase was a highly valuable aid to the nephrologist in managing this problem. Since this agent became unavailable a suitable alternative has not emerged. Recombinant tissue plasminogen activator (tPA) seems to be the most likely candidate for this role; however, it is not currently available in a packaging form that is optimal for this purpose. Currently, catheter exchange appears to be the best available alternative for this problem, which cannot yet be resolved by simpler means.