Preventing complications of radiographic contrast media: is there a role for dialysis?

Nephrologists are often called upon to provide hemodialysis to remove radiographic contrast media in patients with chronic kidney disease (CKD)--usually but not exclusively, those with end-stage renal disease. The reasons for this request vary from concerns over the volume load associated with the administration of a hyperosmolar solution, to the renal and extra-renal toxicities of the contrast itself. Simple calculations demonstrate that the increase in extracellular volume after a typical contrast load is minimal. Data supporting the extra-renal toxicity of contrast in patients maintained on dialysis are lacking. Iodinated contrast agents have molecular weights of 700-1500. This relatively small size as well as their lack of protein binding makes them well suited for removal with extracorporeal renal replacement therapies. Thus, provision of hemodialysis immediately following a contrast load is often utilized in an attempt to prevent further renal damage in patients with advanced stages of CKD. A number of trials have failed to demonstrate that this maneuver is effective. Hemofiltration (HF) has been reported to decrease the risk of acute renal failure in patients with CKD receiving a contrast load, but the studies are methodologically flawed. Therefore, there is currently no sound basis for routinely recommending hemodialysis (or HF) in patients at high risk for contrast media-associated complications.