Importance of oral fluid intake after coronary computed tomography angiography: an observational study

The prevention of contrast-induced acute kidney injury (AKI) after coronary computed tomography angiography (CCTA) is important because patients referred for CCTA often need further contrast exposure such as an invasive coronary angiography. We aimed to examine the effects of oral volume intake on renal function in patients with preserved renal function referred for CCTA.

We enrolled 180 patients who were referred for CCTA. The serum creatinine (SCr) and estimated glomerular filtration rate (eGFR) levels were measured before, 24h, and a mean of 4.8 days after CCTA. The amount of unrestricted oral fluid intake for 24h was checked. The patients were divided into two groups: 106 subjects with a rise in SCr after CCTA (group A); and 74 without (group B).

Significant correlations were observed between the amount of oral fluid intake and the percentage changes in SCr (%SCr) (r=-0.66, p<0.0001) as well as the absolute changes in eGFR (ΔeGFR) (r=0.65, p<0.0001). The percentage of patients showing hemoglobin-A1c (HbA1c)≥6.5% was greater in group A than in group B (29% vs. 18%, p<0.001). Patients with HbA1c≥6.5% showed higher %SCr and lower ΔeGFR compared to those without it. Multiple regression analysis revealed that the amount of oral fluid intake was the only independent predictor for a rise in SCr (β=-0.731, p<0.0001).

Oral volume intake after CCTA is a very simple but important prophylactic procedure for contrast-induced AKI especially in diabetic patients.