Contrast-induced nephropathy: a clinical and evidence-based approach

Effect of rhBNP on renal function in STEMI-HF patients with mild renal insufficiency undergoing primary PCI

This study aims to investigate the effect of recombinant human brain natriuretic peptide (rhBNP) on renal function and contrast-induced nephropathy (CIN) incidence in ST-segment elevation myocardial infarction and heart failure (STEMI-HF) patients with mild renal insufficiency undergoing primary percutaneous coronary intervention (PCI). A total of 116 participants were randomized into rhBNP (rhBNP, n = 57) and nitroglycerin group (NIT, n = 59), receiving intravenous rhBNP or nitroglycerin from admission to 72 h after PCI. Renal function was assessed by serum creatinine (SCr), estimated glomerular filtration rate (eGFR), Cystatin-C (Cys-C) and β2-microglobulin before and after primary PCI, and calculated the incidence of CIN within 72 h after PCI. There were no significant differences in SCr, eGFR and β2-microglobulin between the two groups (P > 0.05, respectively). Compared with the NIT group, the total urinary volume within 72 h was higher while the level of Cys-C at 24 and 72 h after PCI was lower in the rhBNP group. rhBNP was associated with a decline in the incidence of CIN (12.28 vs. 28.81 %, P < 0.05). No differences were detected in mortality and re-hospitalization in 3 months between the two groups. The incidence of renal injury was not different between rhBNP and nitroglycerin in STEMI-HF patients with mild renal insufficiency. However, infusion of rhBNP was associated with a decline in incidence of CIN.

Silica-based nanoparticles: a versatile tool for the development of efficient imaging agents

In this review a selection of the most recent examples of imaging techniques applied to silica-based NPs for imaging is reported.

3D contrast enhancement-MR angiography for imaging of unruptured cerebral aneurysms: a hospital-based prevalence study

Background and Purpose

Contrast enhanced MRA (CE-MRA) can help to overcome the limitations of other techniques to clearly display the details of cerebral aneurysms at 1.5-T MR system. We investigated the prevalence of unruptured cerebral aneurysms (UCAs) using three dimensional (3D) CE-MRA in a tertiary comprehensive hospital in China.

Materials and Methods

The cases were prospectively recorded at our hospital between February 2009 and October 2010. 3D CE-MRA, interpreted by 2 observers blinded to the participants’ information, was used to identify the location and size of UCAs and to estimate the overall, age-specific, and sex-specific prevalence.

Results

Of the 3993 patients (men: women = 2159∶1834), 408 UCAs were found in 350 patients (men: women = 151∶199). The prevalence was 8.8% overall (95% CI, 8.0–10.0%), with 7.0% for men (CI, 6.0–8.0%) and 10.9% for women (CI, 9.0–12.0%). The overall prevalence of UCAs was higher in women than in men (P<0.001) and increased with age both in men and women. Prevalence peaked at age group 75–80 years. Forty-two patients (11.7%) had multiple aneurysms, including 10 (2.9%) male patients and 32 (9.1%) female patients. The most common site of aneurysm was the carotid siphon, and most lesions (71.3%) had a maximum diameter of 3−5 mm.

Conclusion

This hospital-based prevalence study suggested a high prevalence (8.8%) of UCAs and most lesions (71.3%) had a maximum diameter of 3–5 mm observed by 3D CE-MRA. Because the rupture of small cerebral aneurysms was not uncommon, an appropriate follow-up care strategy must be formulated.

Endovascular therapy by CO2 angiography to prevent contrast-induced nephropathy in patients with chronic kidney disease: a prospective multicenter trial of CO2 angiography registry

OBJECTIVES

To assess the safety and efficacy of carbon dioxide (CO2) angiography-guided endovascular therapy (EVT) for renal, iliofemoral artery disease.

BACKGROUND

Patients with peripheral vascular disease (PVD) often have chronic kidney disease (CKD) and the use of iodinated contrast media may enhance the risk of contrast-induced nephropathy (CIN). Contrast volume reduction is an effective CIN preventive strategy.

METHODS

A prospective multicenter registry was developed and six clinical centers participated in the study. Patients with an estimated glomerular filtration rate (eGFR) of <60 ml/min/1.73 m2 and stage-3 CKD were recruited between February 2012 and March 2013. CO2 angiography-guided EVT was performed; incomplete CO2 angiograms were supplemented by intravascular ultrasound, pressure wire, and/or minimal iodinated contrast media. The primary endpoint was a composite of freedom from renal events and freedom from major CO2 angiography related complications.

RESULTS

This study included 98 patients with 109 lesions. The mean eGFR baseline was 35.2±12.7 ml min(-1). CO2 angiography-guided angioplasty were performed in 16 renal arteries, 31 aortoiliac arteries, and 62 superficial femoral arteries. The technical success rate was 97.9%. Average CO2 consumption was 281.4±155.8 ml, average dose of iodinated contrast media was 15.0±18.1 ml. Primary endpoint was 92.8% (91/98). Incidence of CIN was 5.1% (5/98) and CO2 angiography-related complications occurred in 17.3% (17/98). Two cases (2%) developed severe, fatal, nonocclusive mesenteric ischemia (NOMI).

CONCLUSIONS

This trial showed that CO2 angiography-guided angioplasty was effective for preventing CIN, however, CO2 angiography related complication was somewhat high.

Embolization of hypervascular bone metastases reduces intraoperative blood loss: a case-control study

BACKGROUND

Small case series suggest that preoperative transcatheter arterial embolization minimizes bleeding and facilitates surgery for hypervascular metastatic bone tumors. However, control groups would make our confidence in clinical recommendations stronger, but small patient numbers make prospective trials difficult to conduct on this topic.

QUESTIONS/PURPOSES

In this case-control study, we asked whether (1) patients who undergo embolization have less estimated blood loss and/or shorter operative time than patients who do not have embolization; (2) larger tumor size, greater initial tumor vascularity, and longer interval from embolization to surgery are associated with greater estimated blood loss and packed red blood cell transfusion volume; and (3) embolization does not affect renal function in patients with normal preoperative renal function.

METHODS

We retrospectively reviewed records of patients with hypervascular bone metastases treated at our institution between 1998 and 2008. Twenty-seven patients with renal cell carcinoma and 12 with thyroid carcinoma who underwent embolization before 41 surgical procedures were matched to 41 patients who did not have embolization with respect to age, diagnosis, tumor size and potential vascularity, and procedure type; matching was performed without knowledge of outcomes. In univariate and multivariate analyses, age, tumor size, use of embolization, surgery type and risk, embolization-to-surgery interval, and degree of devascularization were evaluated for correlations with estimated blood loss, packed red blood cell transfusion volume, operative time, and postembolization renal function.

RESULTS

Overall, patients who had embolization had less mean estimated blood loss (0.90 versus 1.77 L; p = 0.002), packed red blood cell transfusion volume (2.15 versus 3.56 U; p = 0.020), and operative time (3.13 versus 3.91 hours; p < 0.001). Larger tumor size correlated with greater estimated blood loss (r = 0.451; p = 0.003), packed red blood cell transfusion volume (r = 0.50; p = 0.002), and operative time (r = 0.595; p < 0.001). Neither the interval for embolization to surgery nor the degree of devascularization correlated with estimated blood loss or transfusion volume. In open rodding with intralesional curettage, transcatheter arterial embolization was associated with reduced estimated blood loss, transfusion volume, and operative time. Packed red blood cell transfusion volume was not reduced by embolization in intramedullary nailing procedures with the patient numbers available. Among patients with normal preoperative renal function who had embolization, creatinine levels remained normal. Mild transient, reversible renal function change occurred in one patient with preoperatively abnormal renal function.

CONCLUSIONS

This study suggests that preoperative embolization probably reduces estimated blood loss, particularly for large tumors and during open femoral procedures.

Substantial iodine volume load reduction in CT angiography with dual-energy imaging: insights from a pilot randomized study

We explored whether dual-energy computed tomography (DECT) can allow a significant reduction in iodinated contrast volume during computed tomography angiography (CTA) without hampering image quality or assessibility. We prospectively randomized patients clinically referred to CTA to single energy computed tomography (SECT) with full iodine volume load (group A), DECT with 50 % iodine volume load (group B), DECT with 40 % iodine volume load (group C), and DECT with 30 % iodine volume load (group D); and compared image quality and assessibility. Eighty patients were enrolled and prospectively randomized. The mean age was 61.7 ± 15.0 years and 56 (71 %) patients were male. The demographical characteristics, body mass index, or mean radiation dose did not differ between groups. Significant reductions in total contrast volume were achieved in groups B, C, and D; with mean administrated contrast volumes of 90.3 ± 10.1, 39.5 ± 4.6, 28.3 ± 6.5, and 23.9 ± 6.0 mL, respectively, in groups A to D (p < 0.0001). With regard to image quality, no significant decrease in the Likert scale was observed with reductions of up to 60 % of the contrast volume (groups B and C). DECT at 50-60 keV in association with up to 60 % iodine load reduction, allowed similar signal density, image noise, and signal to noise ratio that SECT imaging with full iodine load. In this pilot, prospective, randomized study, dual energy CTA with up to 60 % iodine volume load reduction provided similar image quality and assessibility than full iodine load with conventional SECT imaging.

Renal function-adjusted contrast volume redefines the baseline estimation of contrast-induced acute kidney injury risk in patients undergoing primary percutaneous coronary intervention

BACKGROUND

Age, estimated glomerular renal function (eGFR), and ejection fraction are preprocedural predictors of contrast-induced acute kidney injury (CI-AKI) after primary percutaneous coronary intervention. The effect of renal function-adjusted contrast volume (CV) remains not totally explored, and a threshold has not yet been established.

METHODS AND RESULTS

Logistic regression and receiver-operating characteristic curve analyses were used to assess whether CV/eGFR was an independent predictor of CI-AKI. The increased discriminative value of CV/eGFR over the preprocedural model based on age, eGFR, and ejection fraction was examined using the net reclassification improvement analysis. Of 470 patients enrolled, we observed 25 (5.3%) cases of CI-AKI. Patients with CI-AKI had received a higher renal function-adjusted CV (CV/eGFR 3.62 versus 1.96; P<0.001), and CI-AKI incidence was higher (15%; P<0.001) in patients in the highest quartile of CV/eGFR, corresponding to the cutoff indicated by the receiver-operating characteristic curve (>2.5; area under the curve, 0.77). At multivariable analysis, CV/eGFR above the cutoff (odds ratio, 5.57; P=0.002) remained an independent predictor of CI-AKI. The model with CV/eGFR demonstrated a statistically significantly net reclassification improvement of 0.23 (P=0.021) over the baseline preprocedural model, largely driven by a correct decrease in risk estimates for patients not experiencing CI-AKI, with a likelihood ratio χ(2) of 5.973 (P=0.029).

CONCLUSIONS

CV remains a key risk factor for CI-AKI after primary percutaneous coronary intervention and our study supports the need for minimizing CV, independently from baseline preprocedural risk. A CV restricted to no more than twice and a half the baseline eGFR might be valuable in reducing the risk of CI-AKI.

Spontaneous tumour lysis syndrome associated with contrast dye iohexol use in mantle cell lymphoma

We describe a case of a 73-year-old man who presented with right-sided abdominal pain associated with palpable mass. Initial laboratory examination was normal except lactate dehydrogenase level. Subsequent CT image showed situs inversus and splenic mass with multiple lymph nodes enlargement. Biopsy taken from the splenic mass demonstrated mantle cell lymphoma. Staging CT examination was performed with intravenous contrast, and patient developed altered mental status, respiratory failure and acute kidney injury requiring intensive care unit care. Laboratory examination revealed hyperuricaemia, hyperphosphataemia, hyperkalaemia and hypocalcaemia, which are consistent with spontaneous tumour lysis syndrome. The patient was successfully treated with rasburicase and haemodialysis, and completed the first course of chemotherapy without further complications.

Caffeic acid phenethyl ester as a protective agent against nephrotoxicity and/or oxidative kidney damage: a detailed systematic review

Caffeic acid phenethyl ester (CAPE), an active component of propolis, has been attracting the attention of different medical and pharmaceutical disciplines in recent years because of its antioxidant, anti-inflammatory, antiproliferative, cytotoxic, antiviral, antifungal, and antineoplastic properties. One of the most studied organs for the effects of CAPE is the kidney, particularly in the capacity of this ester to decrease the nephrotoxicity induced by several drugs and the oxidative injury after ischemia/reperfusion (I/R). In this review, we summarized and critically evaluated the current knowledge regarding the protective effect of CAPE in nephrotoxicity induced by several special medicines such as cisplatin, doxorubicin, cyclosporine, gentamycin, methotrexate, and other causes leading to oxidative renal injury, namely, I/R models and senility.

The challenges in assessing contrast-induced nephropathy: where are we now?

OBJECTIVE

The objective of our study was to exposit the shifting perspectives on contrast-induced nephropathy (CIN) for IV low-osmolar iodinated contrast media.

CONCLUSION

The historically inflated risk of CIN reflects logistic and intellectual pitfalls that continue to confound the study of this disease. Recent advances have clarified that the incidence of CIN is much lower than previously thought, but there are lingering questions. We suggest that CIN is likely real but is rare and offer directions for future study.

Association of contrast-induced acute kidney injury with long-term cardiovascular events in acute coronary syndrome patients with chronic kidney disease undergoing emergent percutaneous coronary intervention

BACKGROUND

The association between contrast-induced acute kidney injury (CI-AKI) and chronic kidney disease (CKD) in patients with acute coronary syndrome (ACS) treated with percutaneous coronary intervention (PCI) has not been fully reported. We evaluated the association of CI-AKI on cardiovascular events in ACS patients with CKD.

METHODS

A total of 1059 ACS patients who underwent emergent PCI in our multicenter registry were enrolled (69±12 years, 804 men, 604 STEMI patients). CKD was defined as at least stage 3 CKD, and CI-AKI was defined as an increase of at least 0.5 mg/dL and/or an increase of at least 25% of pre-PCI to post-PCI serum creatinine levels within 1 week after the procedure. Primary endpoints included cardiovascular death, myocardial infarction, and cerebrovascular disorder (stroke or transient ischemic attack).

RESULTS

In our study, 368 (34.7%) patients had CKD. During follow-up periods (435±330 days), CI-AKI and primary endpoints occurred in 164 (15.5%) patients and 106 (10.0%) patients, respectively. Multivariate Cox proportional hazards model revealed that age, female gender, peak creatinine kinase>4000, IABP use, CI-AKI (hazard ratio [HR], 2.17; 95% confidential interval [CI], 1.52 to 4.00; P<0.001), and CKD (HR, 1.66; 95% CI, 1.01 to 2.72; P=0.046) were independent predictors of primary endpoints. Kaplan-Meier analysis showed that occurrence of primary endpoints increased significantly with an increase in CKD stage, and CI-AKI yielded worse long-term prognosis at every stage of CKD (P<0.001).

CONCLUSIONS

CI-AKI was revealed to be a significant incremental predictor of cardiovascular events at each stage of CKD in ACS patients.

Reduction of circulating endothelial progenitor cell level is associated with contrast-induced nephropathy in patients undergoing percutaneous coronary and peripheral interventions

Objectives

Reduced number and impaired function of circulating endothelial progenitor cells (EPCs) in patients with chronic kidney disease have been reported. However, there is little data about the association between circulating EPC levels and risk of contrast-induced nephropathy (CIN). The aim of this study was to investigate the relationship between circulating EPCs and CIN in patients after angiography.

Methods and Results

A total of 77 consecutive patients undergoing elective percutaneous coronary intervention (PCI) and percutaneous transluminal angioplasty (PTA) were enrolled. Flow cytometry with quantification of EPC markers (defined as CD34⁺, CD34⁺KDR⁺, and CD34⁺KDR⁺CD133⁺) in peripheral blood samples was used to assess EPC number before the procedure. CIN was defined as an absolute increase ≧0.5 mg/dl or a relative increase ≧25% in the serum creatinine level at 48 hours after the procedure. Eighteen (24%) of the study subjects developed CIN. Circulating EPC levels were significantly lower in patients who developed CIN than in those without CIN (CD34⁺KDR⁺, 4.11±2.59 vs. 9.25±6.30 cells/10⁵ events, P<0.001). The incidence of CIN was significantly greater in patients in the lowest EPC tertile (CD34⁺KDR⁺; from lowest to highest, 52%, 15%, and 4%, P<0.001). Using univariate logistic regression, circulating EPC number (CD34⁺KDR⁺) was a significant negative predictor for development of CIN (odds ratio 0.69, 95% CI 0.54–0.87, P = 0.002). Over a two-year follow-up, patients with CIN had a higher incidence of major adverse cardiovascular events including myocardial infarction, stroke, revascularization of treated vessels, and death (66.7% vs. 25.4%, P = 0.004) than did patients without CIN.

Conclusions

Decreased EPC level is associated with a greater risk of CIN, which may explain part of the pathophysiology of CIN and the poor prognosis in CIN patients.

Zwolle risk score predicts contrast-induced acute kidney injury in STEMI patients undergoing PCI

OBJECTIVE

Contrast-induced acute kidney injury (CI-AKI) is a common complication in patients with acute ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). The Mehran risk score was defined originally in elective PCI and may be predictive of CI-AKI. The aim of the present study was to investigate whether the Zwolle score predicts CI-AKI in patients with acute STEMI undergoing primary PCI.

PATIENTS AND METHODS

We analyzed the data of 314 consecutive patients (mean age 56.3 ± 11.4 years) with acute STEMI undergoing primary PCI. The study population was divided into two groups according to CI-AKI development. The Mehran score, Zwolle score, baseline characteristics, and in-hospital outcomes were recorded.

RESULTS

Patients with CI-AKI had higher Mehran and Zwolle scores. In a receiver operating characteristic (ROC) curve analysis, high area under the curve (AUC) values were determined for Zwolle and Mehran scores (0.85 and 0.79, respectively) for CI-AKI development. A Zwolle score greater than  2 predicted CI-AKI with a sensitivity of 76.3 % and a specificity of 75.4 %. A Mehran score greater than 5 predicted CI-AKI with a sensitivity of 71.1 % and a specificity of 73.6 %.

CONCLUSION

Zwolle score predicts CI-AKI slightly better than the Mehran score in patients with STEMI undergoing primary PCI. This simple score can be used at the catheterization laboratory for risk stratification for the development of CI-AKI.

Exposure to low- vs iso-osmolar contrast agents reduces NADPH-dependent reactive oxygen species generation in a cellular model of renal injury

Contrast-induced nephropathy represents the third cause of hospital-acquired acute renal failure. This study investigated the effects of low- vs iso-osmolar contrast medium (CM) exposure on NADPH-dependent reactive oxygen species (ROS) generation by tubular cells. X-ray attenuation of iohexol, iopamidol, and iodixanol was assessed at equimolar iodine concentrations and their effects on human renal proximal tubular cells (PTCs) were evaluated with equally attenuating solutions of each CM. Cytotoxicity, apoptosis, and necrosis were investigated by trypan blue exclusion, MTT assay, and annexin V/propidium iodide assay, respectively. ROS production was assessed by DCF assay, NADPH oxidase activity by the lucigenin-enhanced chemiluminescence method, and Nox4 expression by immunoblot. Yielding the same X-ray attenuation, CM cytotoxicity was assessed in PTCs at equimolar iodine concentrations. More necrosis was present after incubation with iohexol and iopamidol than after incubation with equal concentrations of iodixanol. Iohexol and iodixanol at low iodine concentrations induced less cytotoxicity than iopamidol. Moreover, both iohexol and iopamidol induced more apoptosis than iodixanol, with a dose-dependent effect. ROS generation was significantly higher with iopamidol and iohexol compared to iodixanol. NADPH oxidase activity and Nox4 protein expression significantly increased after exposure to iopamidol and iohexol, with a dose-dependent effect, compared with iodixanol. CM-induced Nox4 expression and activity depended upon Src activation. In conclusion, at angiographic concentrations, iodixanol induces fewer cytotoxic effects on cultured tubular cells than iohexol and iopamidol along with a lower induction of Nox4-dependent ROS generation. This enzyme may, thus, represent a potential therapeutic target to prevent iodinated CM-related oxidative stress.

Pharmacological strategies to prevent contrast-induced acute kidney injury

Contrast-induced acute kidney injury (CI-AKI) is the most common iatrogenic cause of acute kidney injury after intravenous contrast media administration. In general, the incidence of CI-AKI is low in patients with normal renal function. However, the rate is remarkably elevated in patients with preexisting chronic kidney disease, diabetes mellitus, old age, high volume of contrast agent, congestive heart failure, hypotension, anemia, use of nephrotoxic drug, and volume depletion. Consequently, CI-AKI particularly in high risk patients contributes to extended hospitalizations and increases long-term morbidity and mortality. The pathogenesis of CI-AKI involves at least three mechanisms; contrast agents induce renal vasoconstriction, increase of oxygen free radicals through oxidative stress, and direct tubular toxicity. Several strategies to prevent CI-AKI have been evaluated in experimental studies and clinical trials. At present, intravascular volume expansion with either isotonic saline or sodium bicarbonate solutions has provided more consistent positive results and was recommended in the prevention of CI-AKI. However, the proportion of patients with risk still develops CI-AKI. This review critically evaluated the current evidence for pharmacological strategies to prevent CI-AKI in patients with a risk of developing CI-AKI.

Pre-procedural bioimpedance vectorial analysis of fluid status and prediction of contrast-induced acute kidney injury

OBJECTIVES

The aim of this study was to evaluate the relationship between pre-procedural fluid status assessed by bioimpedance vector analysis (BIVA) and development of contrast-induced acute kidney injury (CI-AKI).

BACKGROUND

Accurate fluid management in patients undergoing angiographic procedures is of critical importance in limiting the risk of CI-AKI. Therefore, establishing peri-procedural fluid volume related to increased risk of CI-AKI development is essential.

METHODS

We evaluated the fluid status by BIVA of 900 consecutive patients with stable coronary artery disease (CAD) immediately before coronary angiography, measuring the resistance/height (R/H) ratio and impedance/height (Z/H) vector. CI-AKI was defined as an increase in serum creatinine ≥0.5 mg/dl above baseline within 3 days after contrast administration (iodixanol).

RESULTS

CI-AKI occurred in 54 patients (6.0%). Pre-procedural R/H ratios were significantly higher in patients with CI-AKI than without CI-AKI (395 ± 71 Ohm/m vs. 352 ± 58 Ohm/m, p = 0.001 for women; 303 ± 59 Ohm/m vs. 279 ± 45 Ohm/m, p = 0.009 for men), indicating lower fluid volume in the patients with CI-AKI. When patients were stratified according to R/H ratio, there was an almost 3-fold higher risk in patients with higher values (odds ratio [OR]: 2.9; 95% confidence interval [CI]: 1.5 to 5.5; p = 0.002). The optimal receiver-operating characteristic curve analysis threshold values of R/H ratio for predicting CI-AKI were 380 Ohm/m for women and 315 Ohm/m for men. R/H ratio above these thresholds was found to be a significant and independent predictor of CI-AKI (OR: 3.1; 95% CI: 1.8 to 5.5; p = 0.001).

CONCLUSIONS

Lower fluid status evaluated by BIVA immediately before contrast medium administration resulted in a significant and independent predictor of CI-AKI in patients with stable CAD. This simple noninvasive analysis should be tested in guiding tailored volume repletion.

Incidence of acute kidney injury following cardiac catheterization prior to cardiopulmonary bypass in children

OBJECTIVES

To determine whether contrast administration was a risk factor for development of acute kidney injury (AKI) in cyanotic congenital heart disease (CHD) patients undergoing cardiopulmonary bypass (CPB).

BACKGROUND

AKI following CPB or contrast administration is well described. In previous studies, administration of contrast prior to CPB has been shown to increase the risk of AKI. Chronic cyanosis leads to glomerular damage and dysfunction, thus potentially placing this population at increased risk of developing AKI following contrast administration prior to CPB.

METHODS

One hundred twenty-two patients with cyanotic CHD undergoing preoperative cardiac catheterization (PCC) and subsequent CPB at Children's Medical Center of Dallas from January 1, 2007 until November 30, 2010 were identified, looking specifically at bi-directional Glenn (BDG) anastomoses and Fontan procedures. One hundred thirteen patients undergoing PCC ≤ 48 hr prior to and > 5 days prior to CPB were included. Occurrence of AKI following CPB was the primary outcome variable.

RESULTS

Logistic regression analysis revealed pre-catheterization serum creatinine was a risk factor for post-CPB AKI (P < 0.001) in both Fontan and BDG patients. All other variables were not significantly associated with the development of AKI in either BDG or Fontan patients. Length of stay (hospital or ICU) was not different among the groups regardless of the occurrence of AKI.

CONCLUSIONS

In this study of cyanotic CHD patients, contrast administration within 48 hr prior to CPB was not an additional risk factor for the development of AKI.

N-acetyl cysteine in prevention of amphotericin- induced electrolytes imbalances: a randomized, double-blinded, placebo-controlled, clinical trial

PURPOSE

The aim of this study was to evaluate the effectiveness of oral n-acetyl cysteine, as a potential nephroprotective agent, in preventing and/or attenuating amphotericin B-induced electrolytes imbalances.

METHODS

During a one year period, patients were to receive conventional amphotericin b for any indication for at least one week and were randomly allocated to receive either placebo or 600 mg oral n-acetyl cysteine twice daily during the treatment course of amphotericin b. Demographic and clinical data of the study population were gathered. Different aspects of amphotericin b nephrotoxicity including decrease of glomerular filtration rate, hypokalemia, hypomagnesemia, renal magnesium and potassium wasting were assessed. Each patient was monitored for any adverse reaction to n-acetyl cysteine. Sixteen and 14 patients in the n-acetyl cysteine and placebo groups completed the study, 3incidences of hypokalemia (75 % versus 70 %; P = 0.724) and hypomagnesemia (30 % versus 20 %; P = 0.468) did not differ significantly between placebo and NAC groups, respectively. Although the rate of AmB nephrotoxicity was higher in the placebo than in the NAC group (60 % versus 40 %), this difference was not statistically significant (P = 0.209) even after adjusting for probable associated factors of amphotericin b nephrotoxicity (P = 0.206). The incidence as well as time of onset of electrolyte abnormalities also did not differ significantly between placebo and n-acetyl cysteine groups. About 44 % of n-acetyl cysteine recipients experienced new onset nausea and a mild unpleasant taste during the study.

CONCLUSION

Oral n-acetyl cysteine during the amphotericin B treatment course was not significantly effective in preventing or mitigating different features of its nephrotoxicity including decrease of glomerular filtration rate, hypokalemia, hypomagnesemia, and renal potassium as well as magnesium wasting.

Imaging diagnosis of acute pulmonary embolism

Pulmonary embolism represents a major public healthcare problem and it also imposes frequent clinical diagnostic issues. Despite the availability of the D-dimer tests, imaging remains the mainstay for its diagnosis. Computed tomography pulmonary angiography (CTPA) is now the most widely used diagnostic test and its utility has been well validated in a large number of trials. Nuclear medicine techniques, which are also well established, are now used significantly less frequently. Magnetic resonance pulmonary angiography is developing as an alternative to CTPA in patients who have contraindications to iodinated contrast media. Catheter pulmonary angiography remains the gold standard, although it is being used increasingly less frequently. In this article, we review the current knowledge on the imaging diagnosis of acute pulmonary embolism with special emphasis on the noninvasive techniques.

Remote ischemic preconditioning and renoprotection: from myth to a novel therapeutic option?

There is currently no effective prophylactic regimen available to prevent contrast-induced AKI (CI-AKI), a frequent and life-threatening complication after cardiac catheterization. Therefore, novel treatment strategies are required to decrease CI-AKI incidence and to improve clinical outcomes in these patients. Remote ischemic preconditioning (rIPC), defined as transient brief episodes of ischemia at a remote site before a subsequent prolonged ischemia/reperfusion injury of the target organ, is an adaptational response that protects against ischemic and reperfusion insult. Indeed, several studies demonstrated the tissue-protective effects of rIPC in various target organs, including the kidneys. In this regard, rIPC may offer a novel noninvasive and virtually cost-free treatment strategy for decreasing CI-AKI incidence. This review evaluates the current experimental and clinical evidence for rIPC as a potential renoprotective strategy, and discusses the underlying mechanisms and key areas for future research.

Validation of the J-chronic total occlusion score for chronic total occlusion percutaneous coronary intervention in an independent contemporary cohort

BACKGROUND

Chronic total occlusion (CTO) recanalization is a complex and technically challenging procedure. The J-CTO score has been proposed to stratify case complexity and procedural success rates. However, the score has never been tested outside the setting of the original study. Moreover, its predictive value when using a hybrid antegrade or retrograde approach is unknown. We investigated the performance of the J-CTO score for predicting procedure complexity and success in an independent contemporary cohort.

METHODS AND RESULTS

A total of 209 consecutive patients who underwent CTO recanalization by a high-volume operator were included. Clinical and angiographic data were prospectively collected. The J-CTO score was applied for each patient, and discrimination and calibration were evaluated in the whole cohort, and according to the approach (antegrade 47% and retrograde 53%). Clinical and angiographic differences were noted between the original and studied cohort. The mean J-CTO score was 2.18±1.26, and successful guidewire crossing within 30 minutes and final angiographic success were 44.5% and 90.4%, respectively. The J-CTO score demonstrated good discrimination (c statistic, >0.70) and calibration (Hosmer-Lemeshow P>0.1) in the whole cohort and for antegrade and retrograde approaches. However, the final success rate was not associated with the J-CTO score.

CONCLUSIONS

In this independent cohort, the J-CTO score showed good discriminatory and calibration capacity for guidewire CTO crossing within 30 minutes but it does not for final success rate. The J-CTO score helps to predict complexity of CTO recanalization, and the simplicity of the score supports the widespread use as a clinical tool.

Development of an easily applicable risk score model for contrast-induced nephropathy prediction after percutaneous coronary intervention: a novel approach tailored to current practice

BACKGROUND

Several risk factors for contrast-induced nephropathy (CIN) after percutaneous coronary intervention (PCI) have been identified. The cumulative effect of these risk factors on renal function has been assessed with the development of risk score models in a number of studies. However, concerns were raised that estimates of the risk attributable to individual factors may be unreliable. We sought to develop a simple risk score for developing CIN after PCI irrespective of use of prophylactic measures and also capturing the effect of pre-intervention medication and presence of various co-morbidities.

METHODS

Consecutive patients treated with elective or urgent PCI at our cardiac catheterization laboratory were enrolled (derivation cohort n = 488, validation cohort n = 200). CIN was defined as increase ≥ 25% and/or ≥ 0.5 mg/dl in serum creatinine at 48 h after PCI vs baseline. Multivariable logistic regression analysis was then performed to identify independent predictors of CIN (pre-existing renal disease, metformin use, history of previous PCI, peripheral arterial disease and ≥ 300 ml of contrast volume).

RESULTS

The incidence of CIN in the development cohort was 10.2% with a significant trend across increasing score values (p < 0.001). The model demonstrated good discriminating power (c-statistic 0.759) and excellent calibration (calibration slope 0.91). The model was validated internally by bootstrapping in 1000 samples (c-statistic 0.753) and in a cohort of 200 patients (c-statistic 0.864) demonstrating stable performance.

CONCLUSIONS

The proposed risk score is easily applicable and allows for practically simple risk assessment compared to other published scores while at the same time overcomes drawbacks of previous model designs.

Computed tomography in patients with abdominal pain and diarrhoea: does the benefit outweigh the drawbacks?

The role of computed tomography (CT) in the evaluation of abdominal pain is well established. However, concern exists in regard to procedure-related radiation levels, contrast-medium toxicity and costs. We sought to determine whether the use of abdominal CT caused major changes in the management of patients who had abdominal pain and diarrhoea. We reviewed all abdominal CT examinations that were performed at our hospital from October through December 2010. We selected 574 scans that had been performed in patients who presented with or without diarrhoea. We examined the selected medical records to determine whether the CT scan changed patients' management. A scan was considered to be management changing if a decisive intervention occurred on the basis of the scan results. Among 124 scans in patients with diarrhoea and 450 scans in patients without diarrhoea, the scan results changed management in 13 of the patients with diarrhoea (11%) and in 233 of those without diarrhoea (52%) (P < 0.001). When management changed, the changes resulted from findings unrelated to diarrhoea. Despite its defined role in the assessment of abdominal pain, CT of patients that also had diarrhoea seldom caused a major change in management. The probability of CT causing such a change does not outweigh the cost, radiation risk or potential for contrast-induced nephropathy.

Clinical predictors of contrast-induced acute kidney injury in patients undergoing emergency versus elective percutaneous coronary intervention

BACKGROUND

To evaluate the incidence and clinical predictors of contrast-induced acute kidney injury (CI-AKI) in patients with ST-segment elevation myocardial infarction (STEMI), unstable angina pectoris/non-STEMI (UAP/NSTEMI), and stable AP (SAP) undergoing percutaneous coronary intervention (PCI).

METHODS AND RESULTS

We enrolled 1,954 patients (SAP, n=1,222; UAP/NSTEMI, n=277; STEMI, n=455) who underwent PCI. Patients were categorized according to contrast media volume/estimated glomerular filtration rate ratio (CV/eGFR low: <2.0, mid: 2.0-2.9, high: ≥3.0). CI-AKI was defined as an increase in serum creatinine of 0.5mg/dl or 25% within 1 week from contrast-medium injection. The incidence of CI-AKI was highest among the STEMI patients (SAP, 4.24%; UAP/NSTEMI, 10.7%; STEMI, 16.1%, P<0.01). Significant predictors of CI-AKI were emergency PCI (odds ratio [OR] 3.70; 95% confidence interval [CI] 2.55-5.37; P<0.001), ejection fraction <40% (OR 2.04; 95% CI 1.24-3.36; P=0.005), and hemoglobin <10g/dl (OR 0.02; 95% CI 1.17-4.55; P=0.02) after multivariate logistic regression analysis. In the SAP group, a CV/eGFR ratio ≥3.0 was a significant predictor of CI-AKI (P=0.048), but not in UAP/NSTEMI and STEMI patients.

CONCLUSIONS

UAP/NSTEMI and STEMI patients undergoing emergency PCI were at high risk for CI-AKI regardless of CV/eGFR ratio. Minimizing the dose of contrast medium based on eGFR might be valuable in reducing the risk of CI-AKI in SAP patients.

A simple preprocedural score for risk of contrast-induced acute kidney injury after percutaneous coronary intervention

OBJECTIVE

To develop a simple scoring system based on preprocedural clinical features that is capable of predicting contrast-induced acute kidney injury (CI-AKI) before percutaneous coronary intervention (PCI).

BACKGROUND

CI-AKI is associated with increased in-hospital morbidity and mortality, prolonged hospitalization, and long-term renal impairment. Although several scoring methods have been developed to determine risk of CI-AKI, no simple scoring method based on PCI preprocedural clinical features yet exists for Chinese patients.

METHODS

A total of 2,500 Chinese patients were randomly and retrospectively assigned in a 3:2 manner to create a training and validation dataset, respectively. CI-AKI was defined as an increase of ≥25% or ≥0.5 mg/dL serum creatinine within 5 days after PCI. Preprocedural clinical variables showing independent correlation to CI-AKI were used to derive the risk score from the training dataset and then subsequently tested in the validation dataset. The odds ratios from multivariate logistic regression were used to assign a weighted integer to age ≥70 years = 4, history of myocardial infarction = 5, diabetes mellitus = 4, hypotension = 6, left ventricular ejection fraction ≤45% = 4, anemia = 3, creatinine clearance rate <60 mL/min = 7, decreased high-density lipoprotein <1 mmol/L= 3, and urgent PCI = 3. Summation of the integers represented the total risk score.

RESULTS

The overall incidence of CI-AKI in the training dataset was 16.4% [246/1500; 5.4% for low (≤7) and 61.3% for very high (≥17) risk scores]. The rates of CI-AKI, 1-year dialysis, and 1-year mortality increased significantly with each group (Cochran-Armitage test of trend, P < 0.001). The risk score facilitated appropriate classification of patients with low and high risk for CI-AKI after PCI in the validation dataset (c-statistic = 0.82).

CONCLUSION

Risk classification based on the most significantly correlated parameters is useful for predicting CI-AKI before contrast exposure. The simple preprocedural score showed excellent predictive ability for identifying patients at high risk of nephropathy and those with deteriorative prognosis after PCI.

Longer in-hospital wait times do not result in worse outcomes for patients requiring urgent coronary artery bypass graft surgery

BACKGROUND

In certain health care systems, patients wait for non-emergency services. Although waiting may not be considered acceptable, the delay may allow for patient optimization, such as giving time for "toxic" agents to be cleared, that could improve outcomes. We sought to determine the relationship between wait times and outcomes in in-hospital patients undergoing urgent coronary artery bypass graft (CABG) surgery.

METHODS AND RESULTS

A prospectively collected database of consecutive, medically urgent, but clinically stable patients undergoing CABG surgery from 1995 to 2007, was analyzed. A total of 3067 patients with need for urgent CABG surgery with various in-hospital wait times (n = 440, 0-2 days; n = 799, 3-5 days; n = 1317, 6-10 days; n = 511, 11-15 days) were included. There were no differences in mortality, intensive care unit (ICU) or post-surgery hospital length of stay (LOS) among the patient groups. Multivariate logistic regression analysis revealed that wait time was not associated with mortality (P = 0.625). Due to changes in the nonsurgical management of coronary artery disease, a separate analysis of patients, from 2002 to 2007, was also performed to explore contemporary results. In the latter subset, 1495 patients (n = 175, 341, 720, 259, in the same 4 respective wait-time groups) were included; the 0-2 days patient group underwent more blood transfusions (50% vs 38%; P = 0.01), prolonged ventilation (6% vs 2%; P = 0.05), post-operative dialysis (2% vs 0%; P = 0.08), and longer ICU LOS (26 vs 23 hours; P = 0.02) compared with the 3-5 days patient group. The Society of Thoracic Surgeons mortality risk scores of the 0-2 days and 3-5 days groups were the same (1.5%). Multivariate regression analysis revealed that increased wait time was associated with fewer patients requiring blood transfusion (P < 0.05) for CABG surgery.

CONCLUSION

Waiting for in-hospital urgent CABG surgery does not lead to worse patient outcomes and may, in fact, reduce the procedural and medical risks of postoperative blood transfusions, prolonged ventilation, dialysis, and shorten ICU LOS.

Nano-sized CT contrast agents

Computed tomography (CT) is one of the most widely used clinical imaging modalities. In order to increase the sensitivity of CT, small iodinated compounds are used as injectable contrast agents. However, the iodinated contrast agents are excreted through the kidney and have short circulation times. This rapid renal clearance not only restricts in vivo applications that require long circulation times but also sometimes induces serious adverse effects related to the excretion pathway. In addition, the X-ray attenuation of iodine is not efficient for clinical CT that uses high-energy X-ray. Due to these limitations, nano-sized iodinated CT contrast agents have been developed that can increase the circulation time and decrease the adverse effects. In addition to iodine, nanoparticles based on heavy atoms such as gold, lanthanides, and tantalum are used as more efficient CT contrast agents. In this review, we summarize the recent progresses made in nano-sized CT contrast agents.

Impact of preprocedural high-sensitivity C-reactive protein on contrast-induced nephropathy in patients undergoing primary percutaneous coronary intervention

We assessed the impact of preprocedural high-sensitivity C-reactive protein (hsCRP) on the incidence of contrast-induced nephropathy (CIN) in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (p-PCI). We retrospectively studied 1452 patients with STEMI undergoing p-PCI. Baseline clinical characteristics, CIN incidence, and other inhospital clinical outcomes were compared among hsCRP quartiles; 212 (14.6%) patients developed CIN. The overall inhospital mortality rate was 4.5% (65 patients). Univariate analysis revealed CIN incidence was significantly associated with hsCRP, with 7.44% for quartile Q1 (<3.00 mg/L), 12.6% for Q2 (3.00-5.90 mg/L), 16.9% for Q3 (5.91-11.4 mg/L), and 21.49% for Q4 (>11.4 mg/L; P < .001). Patients with a higher hsCRP experienced a higher rate of inhospital complications. After adjusting for potential confounders, hsCRP >6.50 mg/L was significantly associated with the occurrence of CIN. Preprocedural hsCRP levels are significantly related to the incidence of CIN in patients with STEMI undergoing p-PCI.

Diagnosis and therapy of atheromatous renal artery stenosis

Atheromatous renal artery stenosis (ARAS), a lesion of systemic atherosclerotic disease, is the leading cause of stenotic lesions in the renal artery, followed by fibromuscular dysplasia, a primary abnormality of the renal artery. As a result of several clinical trails, which failed to show an additional benefit of renal revascularization to medical therapy in ARAS, the treatment of ARAS has shifted, and renal revascularization is less commonly performed for ARAS. However, it is recognized that renal revascularization benefits some patients with ARAS. Advances in imaging modalities would allow more frequent detection of ARAS in a society with a growing elderly population, a group with an increased prevalence of systemic atherosclerotic disease. Therefore, it is imperative to identify the patients with ARAS who could benefit from renal revascularization. This review presents a strategy for the treatment of ARAS based on the results of our analysis.

Neutrophil Gelatinase-Associated Lipocalin as an Early Marker of Contrast-Induced Nephropathy After Coronary Angiography

We investigated whether serum neutrophil gelatinase-associated lipocalin (NGAL) was an early predictive biomarker of contrast-induced nephropathy (CIN) in patients with chronic kidney disease (n = 100) undergoing coronary catheterization. Serum creatinine (SCr) levels were measured at baseline, 24 hours, and 48 hours post procedure. Serum NGAL was measured preprocedure, 4 hours, and 24 hours post procedure. The frequency of CIN was 11%. In patients with CIN, SCr achieved significance only at 48 hours ( P = .006), whereas serum NGAL increased ≥25% from baseline at 24 hours in 7 of 11 patients with CIN ( P = .04) but did not change in the other 4. However, serum NGAL also rose ≥25% in 12 of 89 non-CIN patients. This subgroup could have had “incipient CIN.” Serum NGAL delta value at baseline, 24 hours was superior to SCr for early diagnosis of CIN. In conclusion, serum NGAL is an early predictive biomarker for CIN.

Intravenous contrast material-induced nephropathy: causal or coincident phenomenon?

PURPOSE

To determine the causal association and effect of intravenous iodinated contrast material exposure on the incidence of acute kidney injury (AKI), also known as contrast material-induced nephropathy (CIN).

MATERIALS AND METHODS

This retrospective study was approved by an institutional review board and was HIPAA compliant. Informed consent was waived. All contrast material-enhanced (contrast group) and unenhanced (noncontrast group) abdominal, pelvic, and thoracic CT scans from 2000 to 2010 were identified at a single facility. Scan recipients were sorted into low- (<1.5 mg/dL), medium- (1.5-2.0 mg/dL), and high-risk (>2.0 mg/dL) subgroups of presumed risk for CIN by using baseline serum creatinine (SCr) level. The incidence of AKI (SCr ≥ 0.5 mg/dL above baseline) was compared between contrast and noncontrast groups after propensity score adjustment by stratification, 1:1 matching, inverse weighting, and weighting by the odds methods to reduce intergroup selection bias. Counterfactual analysis was used to evaluate the causal relation between contrast material exposure and AKI by evaluating patients who underwent contrast-enhanced and unenhanced CT scans during the study period with the McNemar test.

RESULTS

A total of 157,140 scans among 53,439 unique patients associated with 1,510,001 SCr values were identified. AKI risk was not significantly different between contrast and noncontrast groups in any risk subgroup after propensity score adjustment by using reported risk factors of CIN (low risk: odds ratio [OR], 0.93; 95% confidence interval [CI]: 0.76, 1.13; P = .47; medium risk: odds ratio, 0.97; 95% CI: 0.81, 1.16; P = .76; high risk: OR, 0.91; 95% CI: 0.66, 1.24; P = .58). Counterfactual analysis revealed no significant difference in AKI incidence between enhanced and unenhanced CT scans in the same patient (McNemar test: χ(2) = 0.63, P = .43) (OR = 0.92; 95% CI: 0.75, 1.13; P = .46).

CONCLUSION

Following adjustment for presumed risk factors, the incidence of CIN was not significantly different from contrast material-independent AKI. These two phenomena were clinically indistinguishable with established SCr-defined criteria, suggesting that intravenous iodinated contrast media may not be the causative agent in diminished renal function after contrast material administration.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12121823/-/DC1.

Frequency of acute kidney injury following intravenous contrast medium administration: a systematic review and meta-analysis

PURPOSE

To perform a systematic review and meta-analysis of controlled studies examining the incidence of acute kidney injury (AKI) and other outcomes in patients exposed to intravenous (i.v.) contrast medium compared with patients who underwent an imaging examination without contrast medium or were otherwise unexposed (control group).

MATERIALS AND METHODS

MEDLINE, EMBASE, Scopus, and the Cochrane Library were searched for all articles published through September 2011 that contained search terms related to nephrotoxicity following intravenous contrast medium administration. Two independent reviewers identified studies in which the incidence of AKI in patients exposed to i.v. contrast medium was directly compared with the incidence of AKI in unexposed patients through analysis of changes in serum creatinine level or estimated glomerular filtration rate 48-72 hours following imaging procedures or admission. Study characteristics and outcomes of AKI, dialysis, and mortality were extracted by using a standardized protocol. Relative risk (RR) was calculated by using random-effects models and was tested in subgroups of different patient comorbidities, contrast medium types, and AKI diagnostic criteria. RR results of less than 1.00 indicated that there was a higher incidence of these outcomes in the group that did not receive contrast medium (non-contrast medium group).

RESULTS

Of the 1489 studies originally identified, 13 nonrandomized studies (0.9%) representing 25,950 patients met inclusion criteria. In the group that received contrast medium (contrast medium group), risk of AKI (RR = 0.79; 95% confidence interval [CI]: 0.62, 1.02; P = .07), death (RR = 0.95; 95% CI: 0.55, 1.67; P = .87), and dialysis (RR = 0.88; 95% CI: 0.23, 3.43; P = .85) was similar, compared with the risk of AKI in the non-contrast medium group. This pattern was observed regardless of i.v. contrast medium type, diagnostic criteria for AKI, or whether patients had diabetes mellitus or renal insufficiency.

CONCLUSION

Controlled contrast medium-induced nephropathy studies demonstrate a similar incidence of AKI, dialysis, and death between the contrast medium group and control group.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12121460/-/DC1.

A human serum albumin-thioredoxin fusion protein prevents experimental contrast-induced nephropathy

Contrast-induced nephropathy (CIN), caused by a combination of the direct tubular toxicity of contrast media, a reduction in medullary blood flow, and the generation of reactive oxygen species, is a serious clinical problem. A need exists for effective strategies for its prevention. Thioredoxin-1 (Trx) is a low-molecular-weight endogenous redox-active protein with a short half-life in the blood due to renal excretion. We produced a long-acting form of Trx as a recombinant human albumin-Trx fusion protein (HSA-Trx) and examined its effectiveness in preventing renal injury in a rat model of ioversol-induced CIN. Compared with saline, a mixture of HSA and Trx, or Trx alone, intravenous HSA-Trx pretreatment significantly attenuated elevations in serum creatinine, blood urea nitrogen, and urinary N-acetyl-β-D-glucosaminidase along with the decrease in creatinine clearance. HSA-Trx also caused a substantial reduction in the histological features of renal tubular injuries and in the number of apoptosis-positive tubular cells. Changes in the markers 8-hydroxy deoxyguanosine and malondialdehyde indicated that HSA-Trx significantly suppressed renal oxidative stress. In HK-2 cells, HSA-Trx decreased the level of reactive oxygen species induced by hydrogen peroxide, and subsequently improved cell viability. Thus, our results suggest that due to its long-acting properties, HSA-Trx has the potential to effectively prevent CIN.

Acute kidney injury in patients undergoing cardiac surgery and coronary angiography on the same day

BACKGROUND

Contrast media used for coronary angiography may result in a contrast-induced nephropathy. Acute kidney injury (AKI) is a common complication of cardiac surgery. It has been hypothesized that cardiac surgery in close succession to coronary angiography may increase the risk of postoperative AKI. However, data from the existing literature are conflicting. The aim of this study is to investigate the risk of AKI in patients undergoing angiography and cardiac surgery on the same day, and to assess the efficacy of a policy limiting this practice.

METHODS

A total of 4,440 consecutive patients receiving coronary angiography and cardiac surgery at our institution were retrospectively analyzed. The AKI was defined as stage 1 or stage 2-3 according to the existing classification. Predictive models for AKI stage 1, stage 2-3, and any AKI were built, including various risk factors and the occurrence of surgery on the same day of angiography.

RESULTS

Surgery on the day of angiography was an independent risk factor for AKI stage 2-3 (odds ratio 1.58, 95% confidence interval 1.04 to 2.40). An institutional policy limiting the practice of surgery on the same day of angiography (years 2009 to 2012) resulted in a significant (p = 0.001) 30% decrease of AKI stage 1 and 42% decrease of any AKI with respect to patients operated in the years 2003 to 2008.

CONCLUSIONS

Acute kidney injury after cardiac surgery is a multifactorial event; surgery on the same day of angiography significantly increases the risk of AKI, and limiting this practice results in a containment of the postoperative AKI incidence.

Involvement of caspase-12-dependent apoptotic pathway in ionic radiocontrast urografin-induced renal tubular cell injury

Contrast medium (CM) induces a direct toxic effect on renal tubular cells. This toxic effect subjects in the disorder of CM-induced nephropathy. Our previous work has demonstrated that CM shows to activate the endoplasmic reticulum (ER)-related adaptive unfolding protein response (UPR) activators. Glucose-regulated protein 78 (GRP78)/eukaryotic initiation factor 2α (eIF2α)-related pathways play a protective role during the urografin (an ionic CM)-induced renal tubular injury. However, the involvement of ER stress-related apoptotic signals in the urografin-induced renal tubular cell injury remains unclear. Here, we examined by the in vivo and in vitro experiments to explore whether ER stress-regulated pro-apoptotic activators participate in urografin-induced renal injury. Urografin induced renal tubular dilation, tubular cells detachment, and necrosis in the kidneys of rats. The tubular apoptosis, ER stress-related pro-apoptotic transcriptional factors, and kidney injury marker-1 (kim-1) were also conspicuously up-regulated in urografin-treated rats. Furthermore, treatment of normal rat kidney (NRK)-52E tubular cells with urografin augmented the expressions of activating transcription factor-6 (ATF-6), C/EBP homologous protein (CHOP), Bax, caspase-12, JNK, and inositol-requiring enzyme (IRE) 1 signals. Urografin-induced renal tubular cell apoptosis was not reversed by the inhibitors of ATF-6, JNK signals or CHOP siRNA transfection, but it could be partially reversed by the inhibitor of caspase-12. Taken together, the present results and our previous findings suggest that exposure of CM/urografin activates the ER stress-regulated survival- and apoptosis-related signaling pathways in renal tubular cells. Caspase-12-dependent apoptotic pathway may be partially involved in the urografin-induced nephropathy.