Kidney transplant recipients generally still have kidney disease, with a not-quite fully functioning kidney. So, we must do what we can to protect this lifesaver. One way is to avoid contrast dye when possible.
Contrast-induced nephropathy (CIN) is relatively common in kidney transplant recipients undergoing computed tomography (CT scans) or cardiac catheterization using contrast dyes, researchers concluded in a poster presentation at the 2015 American Transplant Congress.
Researchers studied 76 contrast exposures (45 CT scans and 31 catheterizations) in 50 kidney transplant recipients who had a mean serum creatinine level of 1.46 mg/dL. The investigators identified CIN–defined as a rise in serum creatinine by more than 0.3 mg/dL or 25% from baseline within 4 days of contrast exposure–in ten of 76 procedures (13.2%). Results showed that six (13.3%) of the 45 CT scans and four (12.9%) of the 31 catheterizations resulted in CIN.
The researchers also examined risk factors for CIN. It appeared that exposure to N-acetyl Cysteine (used in pulmonary disease and chest pain, for example) and a lower hemoglobin level were significantly associated with an increased risk of CIN. However, use of calcineurin inhibitors (a class of immunosuppressants that includes tacrolimus cyclosporin) was not. At the last follow-up, CIN did not affect the function and survival of the transplanted kidney, according to the researchers. However, these patients belonged to the researchers who, therefore, may be showing bias.
“Contrast-induced nephropathy is associated with a significant increase in mortality and morbidity,” said lead researcher. “Although we often extrapolate what we know about native kidneys to allografts (transplanted kidneys), that might not reflect best practice. Allografts are solitary kidneys that experience significant hemodynamic alterations and kidney recipients are on lifelong immunosuppressive medications. Both of these factors might affect susceptibility to contrast-induced injury. Since data on CIN in kidney allografts is limited we decided to proceed with this retrospective study.”
CIN is potentially modifiable if risk factors are identified and preventive measures are taken. The 13.3% incidence of CIN identified in the new study is consistent with previous studies looking at native kidneys, according to researchers.
This study was limited by the small sample size and retrospective design.