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

Abstract

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.

Keywords: Coronary computed tomography angiography; Cystatin C; Diabetes mellitus; Renal function; Urinary microalbumin.