Is there a time frame in which you would no longer consider a prior vein mapping study reliable and thus recommend repeating the test in a patient with advanced chronic kidney disease who requires evaluation for fistula placement?

As a standard, typically 6 months is the longest I’d consider utilizing a vein mapping; however, the caveat here is to repeat after any hospitalization or known line placements/extensive blood draws. Vein mapping is very low risk and relatively easy to repeat vs the risk of a failure to mature fistula created that could have been avoided.

I do not think there is a time frame after which a vein mapping study becomes unreliable in assisting a surgeon in the optimum selection of artery and vein for arterio-venous fistula construction. However, if my patient had a PICC (Peripherally Inserted Central Catheter) line placed in the arm or if the radial artery was accessed for cardiac catheterization, I would consider repeating the venous mapping of the arms to evaluate whether those blood vessels could be used for arterio-venous fistula creation.