Contrast-induced nephropathy: what we know, what we think we know, and what we don't know

Evaluation of prediction score of contrast-induced nephropathy in inpatients undergone to digital or CT angiography

Objectives: To assess the incidence of contrast-induced nephropathy (CIN) and determine the Mehran Score's (MS) ability to predict CIN in patients undergoing digital angiography or computed tomography angiography. Methods: 252 medical records of inpatients who underwent DA or CTA over 28 months in a quaternary hospital were reviewed. CIN was defined as serum creatinine> 0.5 mg / dL or > 25% increase in baseline creatinine, 48 h after administration of iodinated contrast. The ROC curve and the area under the curve (AUC) were used as a score test. Results: The majority (159; 63.1%) were male, and the average age was 60.4 years. Anemia, diabetes mellitus, and age > 75 years were the most prevalent factors. The incidence of CIN was 17.8% (n = 45). There was a decrease in the mean values ​​of creatinine pre and post among patients who did not suffer CIN (1.38 ± 1.22 vs 1.19 ± 0.89; t = 3.433; p = 0.0007), while among patients who suffering CIN, the mean increase was 1.03 mg / dL (1.43 ± 1.48 vs 2.46 ± 2.35 mg / dL; t = 5.44; p = 0.117). The ROC curve analysis identified a low correlation between MS and the occurrence of CIN (AUC = 0.506). Conclusion: The incidence of CIN in hospitalized patients undergoing angiography or computed tomography angiography was high. The EM did not allow the prediction of NIC.

Histological and SEM Assessment of Blood Stasis in Kidney Blood Vessels after Repeated Intra-Arterial Application of Radiographic Contrast Media

BACKGROUND

After application of iodinated contrast media (CM), a pronounced deterioration of the microcirculation in skin and myocardium was reported. Clinically, the repeated application of CM, especially, led to an increase of the renal resistance index (RRI). With respect to the transiency of the RRI increase, it is reasonable to assume that the deterioration of blood flow could be due to transient blood stasis caused by reversible morphologic cell alterations due to osmotic discrepancies between CM and human blood. Therefore, the hypothesis was investigated whether CM are able to induce in vivo such blood stasis and cell deformations in the renal vasculature of well-hydrated pigs.

METHODS

The in vivo study was performed as a prospective randomized examination to compare the effects of two different CM in 16 pigs (German Landrace). Pigs were randomized to receive either Iodixanol (n = 8), or Iopromide (n = 8). Each animal received 10 injections separated by 5-min intervals via the suprarenal aorta at a rate of 10 mL/s according to the usual procedure during a cardiac catheter examination. Finally, the kidneys were explanted and processed for histology (H & E staining and fibrin staining according to Weigert) as well as for scanning electron microscopy (SEM) with regards to morphologic correlates explaining the changes in the microcirculation.

RESULTS

In each of the predefined four categories of vascular diameters, blood stasis were found, but clearly more often after application of Iopromide than after application of Iodixanol (p < 0.001). In addition, Iopromide induced more blood stasis in all of the examined kidney regions compared to Iodixanol (p = 0.0001). There were no obstructive events in the middle cortex following the application of Iodixanol. Except for the region around a puncture channel of a placed-in catheter probe, no fibrin was detected in Weigert's fibrin-stained samples, neither around the histologically assessed thrombi nor in vessels with blood stasis. Complementary SEM analyses revealed in a few cases only a slight generation of fibrin and thrombi and deformations, such as echinocyte and "box-like" deformations.

CONCLUSIONS

According to previous in vitro studies, pathological erythrocyte deformations, such as echinocyte and box-like formation of erythrocytes, were observed also in vivo. In addition, blood stasis and/or thrombi could be detected in histological samples from explanted kidneys from young pigs after repeated in vivo administration of CM. In only a few cases, mural platelet aggregates within minimal fibrin meshes occurred only after the application of Iopromide.