Preventing contrast-induced nephropathy: problems, challenges and future directions

Evaluating the Differential Risk of Contrast-Induced Nephropathy Among Diabetic and Non-diabetic Patients Following Percutaneous Coronary Intervention

Background Contrast-induced nephropathy (CIN) significantly complicates percutaneous coronary intervention (PCI), with a higher prevalence in diabetic patients. This study compares the incidence of CIN in diabetic and non-diabetic patients undergoing PCI. Material and methods Conducted at Lady Reading Hospital, Peshawar, PAK, from January to December 2023, this observational study involved 450 adult patients with coronary artery disease (CAD) undergoing PCI. The cohort was categorized based on diabetes status, excluding patients with chronic kidney disease and those on renal replacement therapy. Baseline characteristics documented included age, gender, blood pressure, creatinine levels, and the presence of acute coronary syndrome (ACS). CIN was defined as a ≥25% increase in serum creatinine from baseline within 48-72 hours post-PCI. Data analysis was performed using the Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, IBM Corp., Version 25.0, Armonk, NY), incorporating descriptive statistics, Chi-square tests, and independent t-tests, with a significance level of p<0.05. Results The median age of the study population was 55 years. The cohort comprised 52% male (n=234) and 48% female (n=216). Notably, 33% (n=149) had ACS. Diabetic patients exhibited a significantly higher incidence of CIN post-PCI compared to non-diabetics. The highest incidence of CIN (17%, n=77) occurred in the 70+ age group. The findings highlight the criticality of renal function monitoring and procedural adjustments for diabetic patients. Conclusion Diabetic patients demonstrate an increased risk of CIN following PCI. This necessitates the development of tailored prevention strategies for this high-risk subgroup.

Impact of Supplementation with Omega-3 in the Prevention of Contrast-Induced Nephropathy Following Elective Percutaneous Coronary Intervention in Patients with Chronic Kidney Disease: A Randomized Placebo-Controlled Trial

Background:

Anti-oxidants were investigated in several studies as a preventive strategy for prevention of contrast-induced nephropathy (CIN). Omega-3 polyunsaturated fatty acids have antioxidant properties; however, their role in the prevention of CIN is still unknown. Therefore, in this study, we aimed to evaluate the efficacy of omega-3 supplementation in the prevention of contrast-induced nephropathy following elective percutaneous coronary intervention in patients with chronic kidney disease.

Methods:

This is a double-blinded and randomized clinical trial. Eighty eligible patients with glomerular filtration rate of 30-60 mL/min/1.73 m², scheduled to undergo elective PCI, were randomly divided into omega-3 (a single dose of 2500 mg omega-3 12 hours before PCI plus hydration therapy) or control (placebo plus hydration therapy) groups. Blood specimens for measuring serum creatinine and cystatin C were collected from each patient at baseline and 24 h after PCI.

Results:

Omega-3 did not show any significant effect on post-PCI serum creatinine and cystatin C compared to the controls. In addition, serum creatinine analysis showed that CIN occurred in 6 (16.2%) patients of the omega-3 and 4 (9.3%) patients of the control group (P = 0.50).

Conclusions:

Our results could not support the protective effect of a single dose of omega-3 in decreasing serum creatinine, serum cystatin C, and the incidence of CIN in patients with CKD undergoing PCI. To better evaluate the effect of omega-3, future studies with higher and/or multiple doses of omega-3 are highly recommended.

Carbon dioxide-angiography for patients with peripheral arterial disease at risk of contrast-induced nephropathy

Patients with peripheral arterial disease (PAD) and critical limb ischemia are at risk for limb amputation and require urgent management to restore blood flow. Patients with PAD often have several comorbidities, including chronic kidney disease, diabetes mellitus, and hypertension. Diagnostic and interventional angiography using iodinated contrast agents provides excellent image resolution but can be associated with contrast-induced nephropathy (CIN). The use of carbon dioxide (CO₂) as a contrast agent reduces the volume of iodine contrast required for angiography and reduces the incidence of CIN. However, CO₂ angiography has been underutilized due to concerns regarding safety and image quality. Modern CO₂ delivery systems with advanced digital subtraction angiography techniques and hybrid angiography have improved imaging accuracy and reduced the incidence of CIN. Awareness of the need for optimal imaging conditions, contraindications, and potential complications have improved the safety of CO₂ angiography. This review aims to highlight current technological advances in the delivery of CO₂ in vascular angiography for patients with PAD and critical limb ischemia, which result in limb preservation while preventing kidney damage.

The predictive value of the product of contrast medium volume and urinary albumin/creatinine ratio in contrast-induced acute kidney injury

Preexisting renal impairment and the amount of contrast media are the most important risk factors for contrast-induced acute kidney injury (CI-AKI). We aimed to investigate whether the product of contrast medium volume and urinary albumin/creatinine ratio (CMV × UACR) would be a better predictor of CI-AKI in patients undergoing nonemergency coronary interventions. This was a prospective single-center observational study, and 912 consecutive patients who were exposed to contrast media during coronary interventions were investigated prospectively. CI-AKI is defined as a 44.2 μmol/L rise in serum creatinine or a 25% increase, assessed within 48 h after administration of contrast media in the absence of other causes. Fifty patients (5.48%) developed CI-AKI. The urinary albumin/creatinine ratio (UACR) (OR = 1.002, 95% CI = 1.000–1.003, p = .012) and contrast medium volume (CMV) (OR = 1.008, 95% CI = 1.001–1.014, p = .017) were independent risk factors for the development of CI-AKI. The area under the ROC curve of CMV, UACR and CMV × UACR were 0.662 (95% CI = 0.584–0.741, p < .001), 0.761 (95% CI = 0.674–0.847, p < .001) and 0.808 (95% CI = 0.747–0.896, p < .001), respectively. The cutoff value of CMV × UACR to predict CI-AKI was 1186.2, with 80.0% sensitivity and 62.2% specificity. The product of CMV and UACR (CMV × UACR) might be a predictor of CI-AKI in patients undergoing nonemergency coronary interventions, which was superior to CMV or UACR alone.

Contrast-Induced Acute Kidney Injury: An Update

Contrast-induced acute kidney injury (CI-AKI) is defined as an abrupt deterioration in renal function associated with the administration of iodinated contrast media. This type of acute kidney injury is frequently encountered as a complication of percutaneous coronary intervention (PCI) and is associated with adverse short- and long-term outcomes including mainly mortality, cardiovascular morbidity and prolongation of hospitalization. The incidence of CI-AKI after PCI ranges from 2 to 20 % according to baseline kidney function. It may also range according to the clinical setting, being higher after emergency PCI. The primary manifestation is a small decline in kidney function, occurring 1 to 3 days after the procedure. Kidney function usually returns to preexisting levels within 7 days. Incidence of acute renal failure requiring dialysis following PCI is rare (<1 %). The present article aims to review up-to-date published data concerning diagnosis, definition, epidemiology and prognosis of this novel in-hospital epidemic.

Risk scoring system to predict contrast induced nephropathy following percutaneous coronary intervention

BACKGROUND

Contrast induced nephropathy (CIN) is associated with significant morbidity and mortality after percutaneous coronary intervention (PCI). The aim of this study is to evaluate the collective probability of CIN in Indian population by developing a scoring system of several identified risk factors in patients undergoing PCI.

METHODS

This is a prospective single center study of 1200 consecutive patients who underwent PCI from 2008 to 2011. Patients were randomized in 3:1 ratio into development (n = 900) and validation (n = 300) groups. CIN was defined as an increase of ≥25% and/or ≥0.5 mg/dl in serum creatinine at 48 hours after PCI when compared to baseline value. Seven independent predictors of CIN were identified using logistic regression analysis - amount of contrast, diabetes with microangiopathy, hypotension, peripheral vascular disease, albuminuria, glomerular filtration rate (GFR) and anemia. A formula was then developed to identify the probability of CIN using the logistic regression equation.

RESULTS

The mean (±SD) age was 57.3 (±10.2) years. 83.6% were males. The total incidence of CIN was 9.7% in the development group. The total risk of renal replacement therapy in the study group is 1.1%. Mortality is 0.5%. The risk scoring model correlated well in the validation group (incidence of CIN was 8.7%, sensitivity 92.3%, specificity 82.1%, c statistic 0.95).

CONCLUSION

A simple risk scoring equation can be employed to predict the probability of CIN following PCI, applying it to each individual. More vigilant preventive measures can be applied to the high risk candidates.

Validation of a new risk score to predict contrast-induced nephropathy after percutaneous coronary intervention

Contrast-induced nephropathy (CIN) is a frequent, potentially lethal complication of percutaneous coronary interventions (PCIs). We prospectively validated the diagnostic performance of a simple CIN risk score in a large multicenter international cohort of patients who underwent PCI. About 2,882 consecutive patients treated with elective or urgent PCI were enrolled. A simple CIN risk score was calculated for all patients by allocating points according to a prespecified scale (pre-existing renal disease = 2; metformin use = 2; previous PCI = 1; peripheral arterial disease = 2; and injected volume of contrast medium ≥300 ml = 1). CIN was defined as an increase, compared with baseline, of serum creatinine by ≥25%, or by ≥0.5 mg/dl, 48 hours after PCI. CIN occurred in 15.7% of the study population. The predictive accuracy of the CIN risk score was good (c-statistic 0.741, 95% confidence interval 0.713 to 0.769). Receiver-operating characteristic analysis identified a score of ≥3 as having the best diagnostic accuracy. Examination of the performance of the proposed risk score using different definitions of CIN yielded a robust predictive ability. The score exhibited good discrimination (area under the curve ≥0.700) across all predefined subgroups of the study population. Compared with 2 previously published risk scores for CIN, our score demonstrated higher discriminative ability and resulted in a net reclassification improvement and an integrated discrimination improvement (p <0.001). In conclusion, the new risk score can easily be applied in the setting of urgent or elective PCI, allows for robust risk assessment and offers the potential to improve the peri-interventional management of patients at risk for CIN.

Is contrast medium osmolality a causal factor for contrast-induced nephropathy?

The exact pathophysiology of contrast-induced nephropathy (CIN) is not fully clarified, yet the osmotic characteristics of contrast media (CM) have been a significant focus in many investigations of CIN. Osmotic effects of CM specific to the kidney include transient decreases in blood flow, filtration fraction, and glomerular filtration rate. Potentially significant secondary effects include an osmotically induced diuresis with a concomitant dehydrating effect. Clinical experiences that have compared the occurrence of CIN between the various classes of CM based on osmolality have suggested a much less than anticipated advantage, if any, with a lower osmolality. Recent animal experiments actually suggest that induction of a mild osmotic diuresis in association with iso-osmolar agents tends to offset potentially deleterious renal effects of high viscosity-mediated intratubular CM stagnation.

Contrast-induced nephropathy: pathophysiology and preventive strategies

Contrast-induced nephropathy is the third most common cause of hospital-acquired renal failure, after decreased renal perfusion and nephrotoxic medications. Identification of patients at risk and implementation of preventive strategies can decrease the incidence of this nephropathy. Prevention strategies focus on counteracting vasoconstriction, enhancing blood flow through the nephron, and providing protection against injury by oxygen free radicals. Knowledge of the adverse effects associated with infusion of contrast media, identification of patients at risk for contrast-induced nephropathy, and application of evidence-based prevention strategies allow nurses to assist in the prevention of contrast-induced nephropathy.

Intravascular radiocontrast iodixanol increases permeability of proximal tubule epithelium: a possible mechanism of contrast-induced nephropathy

PURPOSE

To investigate the effect of Iodixanol on kidney proximal tubular cell line human kidney 2 (HK-2).

METHODS

The HK-2 cells were treated with Iodixanol. A Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay was used to evaluate apoptosis. Cell viability was measured by proliferation assay kit. Cell permeability changes were assessed by transwell assay and intercellular gaps measurement. Expression of claudin-2 was assessed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) and Western blot.

RESULTS

Iodixanol reduced tubule cell viability (P < .01) but did not cause apoptosis. The intercellular gap formation (P < .01) and transwell (P < .05) assays revealed that cell permeability significantly increased after Iodixanol treatment of monolayer cells. Western blot and qRT-PCR showed significant upregulation of claudin-2 protein (P < .05) and messenger RNA expression (P < .01).

CONCLUSIONS

Our in vitro data do not support the hypothesis that direct kidney cell death from Iodixanol is a major mechanism of contrast-induced nephropathy (CIN). However, increased permeability of proximal tubule epithelium caused by Iodixanol may play an important role in CIN.

Preventing radiocontrast-induced nephropathy in chronic kidney disease patients undergoing coronary angiography

Radiocontrast-induced nephropathy (RCIN) is an acute and severe complication after coronary angiography, particularly for patients with pre-existing chronic kidney disease (CKD). It has been associated with both short- and long-term adverse outcomes, including the need for renal replacement therapy, increased length of hospital stay, major cardiac adverse events, and mortality. RCIN is generally defined as an increase in serum creatinine concentration of 0.5 mg/dL or 25% above baseline within 48 h after contrast administration. There is no effective therapy once injury has occurred, therefore, prevention is the cornerstone for all patients at risk for acute kidney injury (AKI). There is a small but growing body of evidence that prevention of AKI is associated with a reduction in later adverse outcomes. The optimal strategy for preventing RCIN has not yet been established. This review discusses the principal risk factors for RCIN, evaluates and summarizes the evidence for RCIN prophylaxis, and proposes recommendations for preventing RCIN in CKD patients undergoing coronary angiography.

Epidemiology of contrast material-induced nephropathy in the era of hydration

PURPOSE

To evaluate the incidence of contrast material-induced nephropathy (CIN) in patients with an estimated glomerular filtration rate (eGFR) of less than 60 mL/min/1.73 m(2) who received intravenous contrast media and underwent treatment in accordance with current guidelines and to determine risk factors associated with CIN.

MATERIALS AND METHODS

The research ethics committee waived the requirement for informed consent for this prospective cohort study. All nonhospitalized patients with an eGFR of less than 60 mL/min/1.73 m(2) were seen at a special outpatient clinic. Patients were stratified for the risk of CIN. They were classified as having high or low risk for CIN on the basis of absolute glomerular filtration rate (Modification of Diet in Renal Disease formula result multiplied by body surface area divided by 1.73 m(2)) and the presence of risk factors. Patients at high risk were hydrated with 1000 mL of isotonic saline before and after contrast material exposure. Serum creatinine level was measured 3-5 days later, and CIN was defined as an increase of 25% of more from the baseline level. Risk factors were recorded and compared between patients with CIN and those without CIN by using forward stepwise multiple logistic regression analysis.

RESULTS

A total of 944 procedures in 747 patients were evaluated. Mean age was 71.3 years ± 10 (standard deviation), and 42.9% of patients were female. In 511 procedures (54.1%), patients were hydrated. CIN developed after 23 procedures (2.4%). No patient needed hemodialysis treatment. Heart failure (odds ratio, 3.0), body mass index (BMI) (odds ratio, 0.9), and repeated contrast material administration (odds ratio, 2.8) were found to be independent predictors of CIN.

CONCLUSION

Heart failure, low BMI, and repeated contrast material administration were identified as risk factors for CIN under the current treatment strategy. The low incidence of CIN supports the use of hydration as a preventive measure in patients at high risk for CIN.

Assessment of urinary N-acetyl-β-glucosaminidase as an early marker of contrast-induced nephropathy

Early detection and timely intervention are important for improving contrast-induced nephropathy (CIN) prognosis. Whether urinary N-acetyl-β-glucosaminidase (NAG) is a useful marker for early detection of CIN was investigated in 590 patients undergoing diagnostic coronary angiography (CA) and/or therapeutic percutaneous coronary intervention (PCI) for acute coronary syndromes or stable angina, and who received low-osmolality nonionic contrast agent. Urinary NAG, osmolality and serum creatinine were measured before and 1, 2 and 6 days after contrast agent exposure. CIN occurred in 33 patients; its incidence in high-risk patients (pre-existing renal dysfunction with/without diabetes mellitus) was significantly higher than in others. In patients with CIN, urinary NAG and serum creatinine levels on days 1 and 2 were significantly higher than at baseline and compared with patients without CIN; mean levels were gradually returning to baseline by day 6. Compared with serum creatinine, urinary NAG levels peaked earlier in CIN patients and increased much more. The results suggest that, following CA and/or PCI, CIN occurs to a certain degree and that NAG may be a useful early CIN marker as it is noninvasive, simple, inexpensive and sensitive.

Prevention of contrast-induced acute kidney injury by theophylline in elderly patients with chronic kidney disease

Although the optimal strategy for preventing contrast-induced acute kidney injury (CI-AKI) has not yet been established, the current strategy focuses on adequate periprocedural hydration, the use of a low amount of low or iso-osmolar contrast medium, and the application of adjunctive therapies, including hemofiltration, hemodialysis and drugs. Previous trials and meta-analyses concerning the use of the adenosine antagonist theophylline have revealed contradictory results. We sought to evaluate the effect of theophylline in CI-AKI prevention in well-hydrated elderly patients with chronic kidney disease. We therefore conducted a randomized, double-blind, placebo-controlled trial involving 56 patients who had been referred for cardiac coronary angiography and/or angioplasty. 31 of these patients were randomly assigned to 200 mg theophylline IV before the procedure, and 25 to a placebo. The iso-osmolar contrast medium iodixanol was used. The primary endpoint was an increase in serum creatinine at study termination 48 h after contrast medium administration. Baseline characteristics in the placebo and theophylline groups were similar in terms of median age (75 years), estimated glomerular filtration rate (33 ± 10 vs. 33 ± 10 ml/min/1.73 m²; p = 0.87), diabetes mellitus (80 vs. 71%; p = 0.54), and amount of contrast used (94 ± 35 vs. 95 ± 38 ml; p = 0.89). There was no difference in serum creatinine at baseline (2.06 ± 0.59 vs. 2.02 ± 0.45 mg/dl; p = 0.62) or study termination (2.06 ± 0.68 vs. 2.10 ± 0.53; p = 0.79). A prophylactic effect of theophylline was not observed. The incidence of renal impairment following exposure to the contrast medium was low. This fact can be attributed to adequate parenteral hydratation and the use of the minimum amount of contrast medium necessary.

Epidemiology and natural history of atherosclerotic renovascular disease

Atheromatous renovascular disease (ARVD) is increasingly suspected and diagnosed, and it commonly presents to several different clinical specialties. In this review, the epidemiology, risk factors, comorbid disease associations, natural history, and prognosis of ARVD is described. Atheromatous renovascular disease is strongly associated with macrovascular pathology in other important vascular beds, especially the coronary, aortoiliac and iliofemoral circulations, and also with structural and functional heart disease. These clinicopathologic relationships contribute to the high morbidity and mortality associated with the condition. Understanding of the natural history of renal artery stenosis may enable intensified treatment strategies to reduce associated risk and improve patient prognosis.