Diabetes with preserved renal function is an independent risk factor for renal function deterioration after coronary computed tomography angiography.

OBJECTIVES: Diabetes mellitus (DM) and high fasting glucose levels are reportedly risk factors for contrast-induced nephropathy after invasive coronary angiography in patients with renal dysfunction. Cystatin C (CyC) is a sensitive marker for detecting early impairment of renal function. Using CyC, we investigated whether DM would be a risk for worsening renal function after coronary computed tomography angiography (CCTA) in patients with preserved renal function. METHODS: Two hundred twenty-eight patients scheduled for CCTA were enrolled. The serum CyC at preprocedure and 1 day after procedure, urinary microalbumin at preprocedure, and oral fluid volume for 24 hours after procedure were measured. The percentage changes in CyC from preprocedure to 1 day after procedure (%CyC) were also calculated. RESULTS: Ninety-eight patients had DM. The %CyC and urinary microalbumin were significantly greater in DM patients than in non-DM patients. The percentage of patients showing a %CyC of 10% or greater was significantly greater in DM patients than in non-DM patients (27% vs 8%, P < 0.01). Using multivariate regression analysis, oral fluid volume and urinary microalbumin were independent predictors for a %CyC of 10% or greater in DM patients (ß = - 0.428 [P < 0.0001] and ß = 0.464 [P < 0.0001], respectively). CONCLUSIONS: Diabetes mellitus is a risk factor for worsening changes in renal function after CCTA, even in patients with preserved renal function. In particular, elevated microalbuminuria and low oral fluid intake are high-risk factors for renal functional deterioration.

Cystatin C: a possible sensitive marker for detecting potential kidney injury after computed tomography coronary angiography.

OBJECTIVES: Cystatin C (CyC) has recently been recognized as a sensitive marker for potential renal dysfunction. We investigated the role of CyC for evaluating potential kidney injury after computed tomography coronary angiography (CTCA). METHODS: The CyC, serum creatinine (sCr), estimated glomerular filtration rate (eGFR), and blood urea nitrogen (BUN) levels were evaluated before and 1 day and 1 week after the procedure in 140 patients with preserved renal function referred for CTCA. The amount of unrestricted oral fluid intake was measured for 24 hours after CTCA. The relationship between the amount of oral fluid intake and the changes in each renal marker was compared. RESULTS: A strong correlation was observed between oral fluid volume and the changes in CyC (r = -0.80, P < 0.0001) as well as the changes in sCr (r = -0.54, P < 0.0001) and eGFR (r = 0.57, P < 0.0001), but a weak correlation was observed between oral fluid volume and the changes in BUN (r = -0.22, P = 0.03). A progressive rise in a mean level of CyC was observed. The percentage of diabetic history was greater (73% vs 40%, P < 0.001) and oral fluid volume was lower (1142 mL vs 2114 mL, P < 0.0001) in patients with a rise in CyC but without one in sCr than in those showing a rise in neither CyC nor sCr at 1 day postprocedure. Seventy-four (80%) of 92 patients with a rise in CyC at 1 day postprocedure showed a recovery to the baseline sCr levels at 1 week postprocedure, but only 26 (28%) showed a recovery to the baseline CyC levels at 1 week. CONCLUSIONS: Cystatin C is a more sensitive marker than sCr in evaluating the effects of oral fluid volume on renal function and in detecting potential kidney injury, especially in diabetic patients after CTCA.

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

BACKGROUND: 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. METHODS: 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). RESULTS: 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 (ß=-0.731, p<0.0001). CONCLUSION: Oral volume intake after CCTA is a very simple but important prophylactic procedure for contrast-induced AKI especially in diabetic patients.