Increased pre-procedural urinary microalbumin is associated with a risk for renal functional deterioration after coronary computed tomography angiography.

BACKGROUND: Urinary microalbumin is a marker for preclinical nephropathy. A percentage change in cystatin C (%CyC) of ≥10% for 24h after tests with contrast media is reportedly an independent predictor for developing contrast-induced nephropathy. We investigated the relationship between the presence of urinary microalbumin and changes in CyC after coronary computed tomography angiography (CCTA). METHODS: Three hundred and thirty-three patients with known or suspected coronary artery disease who scheduled for CCTA using a 70mL of Iopamidol were enrolled. Serum creatinine and CyC levels were measured at baseline and 24 h post-procedure. The %CyC, absolute changes in estimated glomerular filtration rate (ΔeGFR), and oral fluid volume from pre- to post-procedure were calculated. The patients were dichotomized into 2 groups as follows: group A comprised 83 patients showing a %CyC of ≥10%; and group B comprised 250 patients showing a %CyC of <10%. RESULTS: The ΔeGFR, fasting plasma glucose levels, HbA1c, and pre-procedural urinary microalbumin levels were significantly greater in group A than in group B. Oral fluid intake volume was significantly less in group A than in group B. The urinary microalbumin significantly correlated with %CyC (r=0.504, P<0.0001). Multivariate logistic regression analysis revealed that pre-procedural urinary microalbumin and oral fluid volume were independent predictors for %CyC≥10%. The optimal cut-off value of a pre-procedural urinary microalbumin level was 58mg/g·creatinine for predicting a %CyC≥10% using receiver-operating-characteristic analysis. CONCLUSIONS: Renal functional changes should be carefully paid attention to after CCTA, particularly in patients exhibiting increased pre-procedural urinary microablumin levels.

Relationship between pre-procedural microalbuminuria and renal functional changes after coronary computed tomography in diabetic patients.

BACKGROUND: Diabetes is one of the risks for development of contrast-induced nephropathy (CIN). The percentage change in cystatin C (CyC), a recent new reliable marker for detecting subtle renal dysfunction, of ≥10% for 24h after procedure is an independent predictor for developing CIN. Urinary microalbumin is one of the markers for preclinical nephropathy in diabetic patients. We investigated the relationship between pre-procedural urinary microalbumin and renal functional changes using CyC after coronary computed tomography angiography (CCTA) in diabetic patients. METHODS: Two hundred and six patients with diabetes scheduled for CCTA were enrolled. The serum creatinine and CyC levels were measured before and 24h after CCTA. The percentage change in CyC (%CyC) and absolute change in estimated glomerular filtration rate (eGFR) from pre- to post-procedure were calculated. The pre-procedural urinary microalbumin was measured. The patients were classified into 2 groups as follows: group A comprised 93 patients with pre-procedural urinary microalbumin of ≥30mg/g creatinine; and group B comprised 113 patients with one of <30mg/g creatinine. RESULTS: The %CyC, fasting plasma glucose levels, and HbA1c were significantly greater in group A than in group B. The absolute change in eGFR was significantly less in group A than in group B. A significant correlation was seen between urinary microalbumin and %CyC (r=0.49, p<0.0001). Multivariate regression analysis revealed that pre-procedural urinary microalbumin and HbA1c were independent predictors for a %CyC≥10% (OR: 1.030, 95% CI: 1.020-1.039, p=0.008; and OR: 1.011, 95% CI: 1.007-1.016, p=0.004, respectively). The optimal cut-off value of a pre-procedural urinary microalbumin level was 64mg/g creatinine for predicting a %CyC≥10% using receiver-operating characteristic curve analysis with a sensitivity, specificity, and area under the curve of 56%, 88%, and 0.72, respectively. CONCLUSIONS: Renal functional changes should be paid attention to after CCTA, particularly in diabetic patients exhibiting elevated pre-procedural urinary microalbumin even though they indicate preserved eGFR.

Predictors of worsening renal function after computed tomography coronary angiography: assessed by cystatin C.

BACKGROUND: An increase in cystatin C (CyC) of ≥10% for 24 hours may predict contrast-induced nephropathy and worse outcomes in patients with renal dysfunction undergoing invasive coronary angiography. OBJECTIVE: We investigated the changes in CyC in patients with preserved renal function referred for contrast-enhanced coronary computed tomography angiography (CTA). METHODS: We studied 151 patients undergoing CTA with 70 mL of iopamidol. Serum creatinine and CyC, a sensitive measure of renal dysfunction, shown to be associated with adverse outcomes, were measured 1 day and 1 week after CTA, respectively. The percentage change in CyC (%CyC) was determined and evaluated in comparison to fluid intake. RESULTS: The patients were dichotomized into 2 groups: 47 patients had ≥10% increase in CyC 1 day after CTA (group A) and 104 did not (group B). The percentage of diabetic patients, hemoglobin A1c (HbA1c), and the CyC levels at 1 week were significantly greater, and the oral fluid volume was significantly lower in group A than in group B. The %CyC inversely correlated with oral fluid volume (r = -0.80, P < 0.0001) and positively with HbA1c (r = 0.38, P < 0.001). Multiple regression analysis showed that oral fluid intake (ß = -0.796, P < 0.0001) and HbA1c (ß = 0.128, P = 0.007) are independent predictors for %CyC of ≥10%. CONCLUSION: Frequency of CyC elevation was strongly related to hydration after the study and also weakly related to HbA1c. Sufficient oral fluid intake (oral fluid volume/kg ≥ 20 mL/kg) is crucial, particularly for poorly controlled diabetic patients referred for CTA even though they show preserved renal function.