Contrast-induced nephropathy: a contemporary and simplified review

Effect of iodine concentration reduction by comparison of virtual monoenergetic image quality with dual-energy computed tomography

This study aimed to evaluate the image quality of virtual monoenergetic images (VMIs) with tube voltage modulation in pediatric abdominal computed tomography (CT) examination and to determine the effect of decreasing contrast agent concentration. Using a 1-year old pediatric phantom, five contrast agent concentration diluent tubes of 100%, 80%, 60%, 40%, and 20% of the same concentration as the average Hounsfield unit (HU) in the descending aorta were inserted, and the mixed image and VMIs (40, 60, and 80 keV) acquired using dual-energy CT were compared with single-energy CT (SECT) images. For quantitative evaluation, the HU and coefficient of variation (COV) of each image were compared and analyzed. The analysis revealed that the HU of the 40 keV VMIs, acquired with a tube voltage of 70 kV and 100% contrast agent concentration, was 61% higher than that of the SECT image. The results showed that SECT had the lowest COV among all contrast agent concentration and tube voltage combinations, while the 40 keV image acquired at 70 kV had the second-lowest COV value. The HU of the 40 keV image acquired at 70 kV at a contrast agent concentration of 100% was 9% higher than that of SECT at 80% concentration. This study confirms that 40 keV VMIs are more useful than SECT images for vascular diagnosis with contrast in pediatric abdominal CT examinations and that a 20% reduction in contrast agent concentration can reduce the risk of contrast agent concentration-induced nephrotoxicity in pediatric patients by increasing the subjective acceptability of image quality for diagnosis.

Efficacy of oral hydration in the prevention of contrast-induced acute kidney injury in patients undergoing coronary angiography or intervention

BACKGROUND

Efficacy of intravenous (IV) volume expansion in preventing contrast-induced acute kidney injury (CI-AKI) is well known. However, the role of oral hydration has not been well established. The aim of this work was to evaluate the efficacy of oral hydration in preventing CI-AKI.

METHODS

We prospectively randomized 225 patients undergoing coronary angiography and/or percutaneous coronary intervention in either oral hydration or IV hydration groups. Patients who have at least one of the high-risk factors for developing CI-AKI (advanced age, type 2 diabetes mellitus, anemia, hyperuricemia, a history of cardiac failure or systolic dysfunction) were included in the study. All patients had normal renal function or stage 1-2 chronic kidney disease. Patients in the oral hydration group were encouraged to drink unrestricted amounts of fluids freely whereas isotonic saline infusion was performed by the standard protocol in the IV hydration group.

RESULTS

CI-AKI occurred in 8/116 patients (6.9%) in the oral hydration group and 8/109 patients (7.3%) in the IV hydration group (p = 0.89). There was also no statistically significant difference between the two groups when different CI-AKI definitions were taken into account.

CONCLUSION

Oral hydration is as effective as IV hydration in preventing CI-AKI in patients with normal kidney function or stage 1-2 chronic kidney disease, and who also have at least one of the other high-risk factors for developing CI-AKI.

The Role of Statins in Preventing Contrast-Induced Acute Kidney Injury

The incidence of contrast-induced acute kidney injury (CI-AKI) is rising due to increased use of coronary angiography and percutaneous coronary intervention. Many agents, including statins, have been evaluated in several studies for the prevention of CI-AKI. To date, there have been 14 prospective randomized studies regarding the efficacy of statins on the patient. Most of these studies and 3 recent meta-analyses have concluded that statins should be used for this purpose, even in patients with reduced low-density lipoprotein cholesterol levels. However, there are also conflicting results, most likely due to marked heterogeneity of patient characteristics, dosage and administration patterns of statins, definition of CI-AKI, and different statistical analyses. In conclusion, it is uncertain whether statins should be prescribed to prevent CI-AKI in the absence of other indications.

Association between Glycosylated Haemoglobin Level and Contrast-Induced Acute Kidney Injury in Patients with Type 2 Diabetes Mellitus

BACKGROUND

There are several reports suggesting that admission hyperglycaemia increases the risk of contrast-induced acute kidney injury (CI-AKI). However, it is not clear whether there has been an association between long-standing poor glycaemic control and the incidence of CI-AKI. The purpose of this study was to examine the impact of poor glycaemic control or elevated glycosylated haemoglobin (HbA1c) on the incidence of CI-AKI in patients with type 2 diabetes mellitus (T2DM).

METHODS

The present study prospectively enrolled 133 patients with T2DM undergoing elective coronary angiography (CAG) and/or intervention. All patients had an estimated glomerular filtration rate (eGFR) of ≥60 ml/min/1.73 m(2). Patients were divided into two groups: those with an optimal HbA1c (<7%) and those with an elevated HbA1c (≥7%). All had similar baseline characteristics and were hydrated appropriately. The outcome was assessed by the incidence of CI-AKI.

RESULTS

CI-AKI occurred in 2 of 41 patients (4.9%) with optimal HbA1c levels and 5 of 92 patients (5.4%) with elevated HbA1c levels (p = 0.89). The cutoff point of HbA1c was set at 6.5%, but no statistically significant difference between the two groups was observed [1 of 24 patients (4.1%) vs. 6 of 109 patients (5.5%), p = 0.79]. However, despite a high variability in the incidence of CI-AKI, there was no statistically significant difference between the two groups when varying CI-AKI definitions were considered.

CONCLUSION

An elevated HbA1c level is not associated with a higher incidence of CI-AKI compared to optimal HbA1c levels in patients with T2DM (patients with an eGFR of ≥60 ml/min/1.73 m(2)) undergoing CAG and/or intervention.