Contrast-Induced Nephropathy in the Management of Lower Gastrointestinal Bleeding

Purpose It is not uncommon for patients with lower gastrointestinal bleeding (LGIB) to have underlying chronic kidney disease (CKD). Computed tomography angiography (CTA) has recently become the initial diagnostic imaging study in localization of LGIB. However, practitioners are often wary of ordering CTAs for patients with pre-existing renal impairment due to the perceived significant risk of contrast-induced nephropathy (CIN). This clinical dilemma may result in delay of appropriate diagnostic management or perhaps unnecessary more invasive diagnostic tests.

Materials and Methods A retrospective, institutional review board (IRB) approved analysis of all CTAs was performed for LGIB between March 2014 and October 2016 (n = 108). To ensure a higher pretest likelihood of nephrotoxicity, only Stage II and higher CKD patients were included, using National Kidney Foundation definitions and glomerular filtration rate (GFR). Acute kidney injury (AKI) was defined as increase in creatinine of 0.5 mg/dL or >25% above baseline within 48 to 72 hours after contrast.

Results Twenty-two patients met entry criteria; of these 3 had stage II (13%), 15 stage III (68%), 2 stage IV (9%), and 2 Stage V (9%) CKD. Additionally, 9 (41%) of the 22 patients underwent conventional angiography within 24 hours of the initial CTA. Contrast administered for each CTA was 100 mL. Despite their elevated risks, only 1 of 22 patients who had stage III CKD (4%) developed AKI, which did not require treatment.

Conclusion CTA can be performed safely with a low risk of developing CIN in patients with Stage II to V CKD and concurrent LGIB.

No conflict of interest has been declared by the author(s).