Contrast-induced nephropathy in urological imaging: A comparison with cardiology interventions

Randomized trial to assess the potential role of ascorbic acid and statin for post-contrast acute kidney injury prevention

PURPOSE

To evaluate the effect of using statins and ascorbic acid for the prevention of post-contrast acute kidney injury (PC-AKI) in patients undergoing urologic diagnostic elective contrast-enhanced computed tomography (CECT).

METHODS

This registered trial (NCT03391830) was for statin naïve patients underwent elective CECT. Patients were randomized allocated to two groups: the first group received atorvastatin 80-mg the day before the study and atorvastatin 40-mg two hours before the CECT and for continue on atorvastatin 40-mg two days after CECT; plus ascorbic acid 500 mg with atorvastatin. The other group received two tablets of placebo once/daily before the procedure and for another 3 days. The primary outcome was to assess the incidence PC-AKI.

RESULTS

The baseline parameters were comparable between both groups. The final median (interquartile range "IQR") serum creatinine were 0.80 (0.60, 1.00) and 0.80 (0.60, 1.00), respectively, with insignificant p-value (p = 0.8). The median (IQR) final estimated GFR were 95.2 (72.8, 108.1) and 88.6 (71.9, 111.0) mL/min in placebo and statin plus ascorbic acid groups, respectively (p = 0.48). The eGFR difference median (IQR) were - 6.46 (- 11.72, - 4.18) and - 6.57 (- 13.38, - 3.82) ml/min in placebo and statin plus ascorbic acid groups, respectively (p = 0.58). PC-AKI occurred in 11 patients (9.8%) in placebo group and in 3 patients (3%) in statin plus ascorbic acid group (p = 0.04).

CONCLUSIONS

Statin and ascorbic acid did not statistically improve neither serum creatinine nor eGFR values in patient underwent CECT. However, it can decrease the incidence of the clinically insignificant PC-AKI.

A Simplified Risk Score to Estimate the Risk of Contrast-Induced Nephropathy after Contrast Exposure

Introduction

Scores are available to predict the probability of contrast-induced nephropathy (CIN) after cardiac interventions, but not many scores are available for non-cardiac interventions and there are none for intravenous exposure to contrast. We designed this study to develop a simplified score to determine the probability of developing CIN in patients exposed to the parenteral contrast medium.

Methods

This was a prospective study of patients who received parenteral contrast. Of 1300 patients, the first 1000 comprised the derivation cohort and the next 300 comprised the validation cohort. The patient variables in the development cohort were studied using univariate analysis. Statistically significant individual variables were used as independent variables, and CIN was used as the dependent variable in the final multivariate logistic regression model. Then, the risk score was obtained and validated.

Results

The incidence of CIN was 3.8%. The risk factors, namely the presence of diabetes mellitus, e-GFR, and route and volume of contrast material were significantly associated with the risk of CIN (P < 0.05). The developed risk score had a sensitivity of 90.4% and specificity of 98.78%. The overall accuracy was 97.8%. The values of AUC of ROC in the development and validation datasets were high. This indicated that the predicted CIN risk score correlated well with the calibration and discriminative characteristics.

Conclusions

The route and volume of contrast administered, low e-GFR, and diabetes mellitus were the significant risk factors. The developed risk score exhibited very good sensitivity and specificity and excellent accuracy in predicting the probability of CIN.

Ocular Blood Flow in Rabbits under Deep Anesthesia: A Real-Time Measurement Technique and Its Application in Characterizing Retinal Ischemia

In this study, we reported a new technique based on laser speckle flowgraphy to record the ocular blood flow in rabbits under deep anesthesia, and proposed parameters to characterize retinal ischemia. We applied the proposed technique to study the correlation of blood flow between the eyes of normal non-anesthetized animals, and to characterize the occlusion of the internal carotid artery (ICA) and external carotid artery (ECA). We established a correlation in blood flow between the eyes of non-anesthetized animals, and derived two new parameters, namely, the laterality index and vascular perfusion estimate (VPE). Our experimental results from 16 eyes (of 13 New Zealand white rabbits) showed a reduction in ocular blood flow with a significant decrease in the VPE after the occlusion of the ECA (p < 0.001). A low/minimal effect on blood flow was observed with the occlusion of the ICA. In conclusion, we demonstrated a means for the real-time measurement of the ocular blood flow in rabbits under deep anesthesia by using laser speckle flowgraphy and the VPE as an indicator of successful occlusion. The proposed technique might be applicable in quantifying the efficacy of new drugs and interventions for the treatment of retinal ischemia.