Lack of impact of iodinated contrast media on kidney cell-cycle arrest biomarkers in critically ill patients

Iodinated Contrast and Nephropathy: Does It Exist and What Is the Actual Evidence?

Iodinated contrast material (ICM) is a critical component for many radiologic examinations and procedures. However, ICM has often been withheld in the past out of concern for its potential nephrotoxicity and increased risk of morbidity and mortality, often at the expense of diagnostic accuracy and timely diagnosis. Evidence from controlled studies now suggest that most cases of acute kidney injury (AKI) caused by ICM were instead due to contrast-independent causes of AKI or normal variation in renal function. This study will discuss current knowledge of contrast-induced AKI, including the incidence, sequelae, risk factors, and prevention strategies of this potential complication.

Evaluation of the Diagnostic Utility of Urine Biomarkers Tissue Inhibitor of Metalloproteinases-2 (TIMP-2) and Insulin-like Growth Factor Binding Protein-7 (IGFBP-7) in Predicting Acute Kidney Injury and Short-term Outcomes among High-risk, Critically Ill Patients in a Tertiary Government Hospital in the Philippines

BackgroundandObjectives

Acute kidney injury (AKI) is a common complication of critical illness that often leads to increased mortality and morbidity. Biomarkers detect AKI earlier, providing a window of opportunity for timely intervention. Of the recent biomarkers in literature, the cell cycle arrest biomarkers tissue inhibitor of metalloproteinases-2 (TIMP-2) and insulin-like growth factor binding protein-7 (IGFBP-7) were found to be superior in predicting AKI. Our study aimed to evaluate the diagnostic performance of urine TIMP-2/IGFBP-7 in its ability to predict AKI and major adverse kidney events within 30 days (MAKE30) among high-risk patients for AKI. MAKE30 is a composite outcome comprised of all-cause mortality, use of renal replacement therapy (RRT), or persistent renal dysfunction at hospital discharge truncated at 30 days.

Methods

We conducted a prospective, cross-sectional study which included 135 adult, non-COVID ICU patients. Baseline urine TIMP-2/IGFBP-7 results were used to dichotomize the population into low risk (<0.3 ng/mL) or high risk (≥0.3 ng/mL) for AKI. Participants were then observed for 30 days and monitored for MAKE30 outcomes. ROC curves were created to calculate the sensitivity, specificity, NPV, PPV, and the AUC of the 0.3 ng/mL cut-off to predict the AKI and MAKE30.

Results

Urine TIMP-2/IGFBP-7 cutoff of 0.3 ng/mL predicted AKI with a sensitivity of 82.4%, specificity of 79.2%, PPV of 57.1%, NPV of 93% and AUC of 0.81. MAKE30 was detected with a sensitivity of 62.8%, specificity of 76.1%, PPV of 55.1%, NPV of 81.4% and AUC of 0.69. Elevated levels of urine TIMP-2/IGFBP-7 were found to be associated with AKI (p<0.01), MAKE30 (p<0.01) and all of its subcomponents. Survival or discharge after 30 days were found to be associated with lower urine TIMP-2/IGFBP-7 levels (p<0.01).

Conclusions

Urine TIMP-2/IGFBP-7, at its current cut-off at 0.3 ng/mL, can predict the likelihood of developing AKI and major adverse kidney events among high-risk patients for AKI. It can serve as a useful adjunct to existing methods, such as serum creatinine, in the early diagnosis and prognosis of acute kidney injury and expanding the therapeutic window to prevent disease progression and improve outcomes.

[Biomarkers of oxidative stress and inflammation in contrast-associated acute kidney injury]

BACKGROUND

Iodinated contrast-induced acute kidney injury (CI-AKI) is a common cause of renal failure, especially in patients with risk factors. This study analyses different renal biomarkers in patients undergoing computed tomography scans with iodinated contrast to identify the molecular and cellular mechanisms involved in the pathogenesis of CI-AKI.

METHODOLOGY

Prospective study that included patients with high risk of renal disease who received iodinated contrast (iohexol) for the computed tomography scans. Functional biomarkers (creatinine and cystatin C), inflammatory and oxidative stress markers (neutrophil gelatinase-associated lipocalin [NGAL], interleukin-8 [IL-8], superoxide dismutase [SOD], F2-isoprostanes, and cardiotrophin-1), and cell cycle biomarkers (Nephrocheck®) were analysed before the iodinated contrast and 4, 12, 24, and 48 hours post-contrast, in relation to the incidence of IC-AKI.

RESULTS

IC-AKI was observed in 30.6% of the 62 study participants and in 57.1% of the patients with diabetes and renal dysfunction. Factors associated with IC-AKI were a higher mean age (74.4 vs 64.9 years), pre-existing renal dysfunction (60 vs 16.7%), and higher adjusted mean volume of iohexol (42.9 vs 32.1%). As for non-functional biomarkers. No differences were found between patients with and without CI-AKI. The use of iodinated contrast was associated with a decrease in SOD antioxidant activity at 4 hours and an increase in IL-8 at 12 hours post-administration of the iodinated contrast.

CONCLUSIONS

Administration of iohexol in computed tomography scans in patients with high risk of renal disease results in an elevated percentage of CI-AKI, attributable to ischemia/reperfusion injury and/or direct toxicity of the iodinated contrast.

Risk of Acute Kidney Injury Following IV Iodinated Contrast Media Exposure: 2023 Update, From the AJR Special Series on Contrast Media

Iodinated contrast material (ICM) has revolutionized the field of diagnostic radiology through improvements in diagnostic performance and the expansion of clinical indications for radiographic and CT examinations. Historically, nephrotoxicity was a feared complication of ICM use, thought to be associated with a significant risk of morbidity and mortality. Such fears often precluded the use of ICM in imaging evaluations, commonly at the expense of diagnostic performance and timely diagnosis. Over the past 20 years, the nephrotoxic risk of ICM has become a topic of debate, as more recent evidence from higher-quality studies now suggests that many cases of what was considered contrast-induced acute kidney injury (CI-AKI) likely were cases of mistaken causal attribution; most of these cases represented either acute kidney injury (AKI) caused by any of myriad other known factors that can adversely affect renal function and were coincidentally present at the time of contrast media exposure (termed "contrast-associated AKI" [CA-AKI]) or a manifestation of the normal variation in renal function that increases with worsening renal function. This Special Series Review discusses the current state of knowledge regarding CI-AKI and CA-AKI, including the incidence, risk factors, outcomes, and prophylactic strategies in the identification and management of these clinical conditions.

Kidney Cell Cycle Arrest and Cardiac Biomarkers and Acute Kidney Injury Following Angiography: The Prevention of Serious Adverse Events Following Angiography (PRESERVE) Study

Rationale & Objective

Recent studies in patients with chronic kidney disease (CKD) indicate that most cases of contrast-associated acute kidney injury (CA-AKI) are mild and are not associated with elevation in kidney injury biomarkers. We used highly sensitive kidney cell cycle arrest and cardiac biomarkers to assess the risk of CA-AKI and major adverse kidney events in patients with CKD undergoing angiography.

Study Design

A retrospective study.

Setting & Participants

A subset of 922 participants from the Prevention of Serious Adverse Events following Angiography trial.

Predictors

Pre- and postangiography urinary tissue inhibitor of matrix metalloproteinase [TIMP]-2 and insulin growth factor binding protein [IGFBP]-7 were measured in 742 subjects, and plasma β natriuretic peptide (BNP) and high-sensitivity C-reactive protein (hs-CRP), and serum troponin (Tn) in 854 participants using samples obtained 1-2 hours before and 2-4 hours after angiography.

Outcomes

CA-AKI and major adverse kidney events.

Analytical Approach

We fitted logistic regression to examine association and area under the receiver operating characteristic curves for risk prediction.

Results

There were no differences in postangiography urinary [TIMP-2]•[IGFBP7], plasma BNP, serum Tn, and hs-CRP concentrations among patients with and without CA-AKI and major adverse kidney events. However, higher pre- and postangiography median plasma BNP (pre: 200.0 vs 71.5, pg/mL, P = 0.05; post: 165.0 vs 81 pg/mL, P = 0.02); serum Tn (pre: 0.03 vs 0.01, ng/mL, P < 0.001; post, 0.04 vs 0.02, ng/mL, P = 0.01); and hs-CRP (pre: 9.55 vs 3.40 mg/L, P = 0.01; post: 9.90 vs 3.20 mg/L, P = 0.002) concentrations were associated with major adverse kidney events, although their discriminatory capacity was only modest (area under the receiver operating characteristic curves <0.7).

Limitations

Most participants were men.

Conclusions

Most mild CA-AKI cases are not associated with urinary cell cycle arrest biomarker elevation. Significant elevation in preangiography cardiac biomarkers may reflect patients with more significant cardiovascular disease that may predispose to poor long-term outcomes independent of CA-AKI status.

Acute kidney injury in neurocritical patients: a retrospective cohort study

BACKGROUND /OBJECTIVE

Acute kidney injury (AKI) is a significant complication in critical care units (CCU). Non-neurological complications such as AKI are an independent predictor of poor clinical outcomes, with an increase in morbidity and mortality, financial costs, and worse functional recovery. This work aims to estimate the incidence of AKI and evaluate the risk factors and complications of AKI in neurocritical patients hospitalized in the CCU.

METHODS

A retrospective cohort study was conducted. Patients admitted to the neurocritical care unit between 2016 and 2018 with a stay longer than 48 h were retrospectively analyzed in regard to the incidence, risk factors, and outcomes of AKI.

RESULTS

The study population comprised 213 neurocritical patients. The incidence of AKI was 23.5%, with 58% KDIGO 1 and 2% requiring renal replacement therapy. AKI was an independent predictor of prolonged use of mechanical ventilation, cerebral edema, and mortality. Cerebral edema [OR 4.40 (95% CI 1.98-9.75) p < 0.001] and a change in chloride levels greater than 4 mmol/L at 48 h (OR 2.44 (95% CI 1.10-5.37) p = 0.027) were risk factors for developing AKI in the first 14 days of hospitalization.

CONCLUSION

There is a high incidence of AKI in neurocritical patients; it is associated with worse clinical outcomes regardless of the CCU admission etiology or AKI severity.

Contrast associated nephropathy after intravenous administration: what is the magnitude of the problem?

Intravenous contrast media (CM) is often used in clinical practice to enhance CT scan imaging. For many years, contrast-induced nephropathy (CIN) was thought to be a common occurrence and to result in dire consequences. When treating patients with abnormal renal function, it is not unusual that clinicians postpone, cancel, or replace contrast-enhanced imaging with other, perhaps less informative tests. New studies however have challenged this paradigm and the true risk attributable to intravenous CM for the occurrence of CIN has become debatable. In this article, we review the latest relevant medical literature and aim to provide an evidence-based answer to questions surrounding the risk, outcomes, and potential mitigation strategies of CIN after intravenous CM administration.

Acute kidney injury in the critically ill: an updated review on pathophysiology and management

Acute kidney injury (AKI) is now recognized as a heterogeneous syndrome that not only affects acute morbidity and mortality, but also a patient’s long-term prognosis. In this narrative review, an update on various aspects of AKI in critically ill patients will be provided. Focus will be on prediction and early detection of AKI (e.g., the role of biomarkers to identify high-risk patients and the use of machine learning to predict AKI), aspects of pathophysiology and progress in the recognition of different phenotypes of AKI, as well as an update on nephrotoxicity and organ cross-talk. In addition, prevention of AKI (focusing on fluid management, kidney perfusion pressure, and the choice of vasopressor) and supportive treatment of AKI is discussed. Finally, post-AKI risk of long-term sequelae including incident or progression of chronic kidney disease, cardiovascular events and mortality, will be addressed.

Iodinated contrast medium: Is there a re(n)al problem? A clinical vignette-based review

As we were taught, for decades, that iodinated contrast-induced acute kidney injury should be dreaded, considerable efforts were made to find out effective measures in mitigating the renal risk of iodinated contrast media. Imaging procedures were frequently either downgraded (unenhanced imaging) or deferred as clinicians felt that the renal risk pertaining to contrast administration outweighed the benefits of an enhanced imaging. However, could we have missed the point? Among the abundant literature about iodinated contrast-associated acute kidney injury, recent meaningful advances may help sort out facts from false beliefs. Hence, there is increasing evidence that the nephrotoxicity directly attributable to modern iodinated CM has been exaggerated. Failure to demonstrate a clear benefit from most of the tested prophylactic measures might be an indirect consequence. However, the toxic potential of iodinated contrast media is well established experimentally and should not be overlooked completely when making clinical decisions. We herein review these advances in disease and pathophysiologic understanding and the associated clinical crossroads through a typical case vignette in the critical care setting.

A Randomized Trial of Recombinant Human C1-Esterase-Inhibitor in the Prevention of Contrast-Induced Kidney Injury

OBJECTIVES

This study sought to determine the efficacy profile and safety of recombinant human C1 esterase inhibitor (rhC1INH) in the prevention of contrast-associated acute kidney injury after elective coronary angiography.

BACKGROUND

Contrast-associated acute kidney injury is caused by tubular cytotoxicity and ischemia/reperfusion injury. rhC1INH is effective in reducing renal ischemia/reperfusion injury in experimental models.

METHODS

In this placebo-controlled, double-blind, single-center trial 77 patients with chronic kidney disease were randomized to receive 50 IU/kg rhC1INH before and 4 h after elective coronary angiography or placebo. The primary outcome was the peak change of urinary neutrophil gelatinase-associated lipocalin within 48 h, a surrogate marker of kidney injury.

RESULTS

Median peak change of urinary neutrophil gelatinase-associated lipocalin was lower in the rhC1INH group (4.7 ng/ml vs. 22.5 ng/ml; p = 0.038) in the per-protocol population but not in the modified intention-to-treat analysis, and in patients with percutaneous coronary interventions (median, 1.8 ng/ml vs. 26.2 ng/ml; p = 0.039 corresponding to a median proportion peak change of 11% vs. 205%; p = 0.002). The incidence of a cystatin C increase ≥10% within 24 h was lower in the rhC1INH group (16% vs. 33%; p = 0.045), whereas the frequency of contrast-associated acute kidney injury was comparable. Adverse events during a 3-month follow-up were similarly distributed.

CONCLUSIONS

Administration of rhC1INH before coronary angiography may attenuate renal injury as reflected by urinary neutrophil gelatinase-associated lipocalin and cystatin C. The safety profile of rhC1INH was favorable in a patient population with multiple comorbidities. (Recombinant Human C1 Esterase Inhibitor in the Prevention of Contrast-induced Nephropathy in High-risk Subjects [PROTECT]; NCT02869347).

Investigation of Various Intramuscular Volumes Delivered to the Semimembranosus Muscle of Cavia porcellus

The goal of this study is to provide quantitative data on the ideal volume for intramuscular (IM) injections into the semimembranosus muscle of guinea pigs weighing between 320 to 410 grams. This evaluation comprised 2 experiments. The first was to assess dispersion leakage of intramuscularly injected iohexol, a radiocontrast agent commonly used in Computed Tomography (CT), based on analysis of in vivo imaging. The second used varying volumes of intramuscularly injected sodium chloride (0.9% NaCl) to assess pain and pathology associated with IM injection. Hartley guinea pigs were injected IM with varying volumes of either iohexol or sodium chloride (150, 300, 500, 1000 and 1500 μL). In the iohexol experiment, results suggest IM volumes of 150 and 300 μL remain within the target muscle. In the experiment using sodium chloride, pain and pathology did not increase as IM volume increased. The pathology noted was related to needle tract through the musculature rather than the volume size of the injectate. The results did not reveal a correlation between volume of IM 0.9% NaCl and pain levels. We conclude that volume size correlates more with precision and accuracy of delivery into the intended muscle tissue. Regarding tissue distribution, our findings also suggest that the optimal capacity for IM injection in the semimembranosus muscle should be less than 500 μL.