Prophylaxis in High-Risk Patients With eGFR < 30 mL/min/1.73 m2: Get the Balance Right

Effects of intravenous hydration in preventing post-contrast acute kidney injury in patients with eGFR < 30 mL/min/1.73 m2

OBJECTIVES

To investigate the effects of intravenous hydration in preventing post-contrast outcomes in patients with estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73 m2 undergoing intravenous administration of iodinated contrast media (ICM).

METHODS

Hospitalized patients with eGFR < 30 mL/min/1.73 m2 and intravenous ICM exposure between 2015 and 2021 were included. Post-contrast outcomes include post-contrast acute kidney injury (PC-AKI) (defined by 2012 Kidney Disease: Improving Global Outcomes (KDIGO) or European Society of Urogenital Radiology (ESUR)), chronic dialysis at discharge, and in-hospital mortality. Confounding effects between the two groups were reduced to a minimum using propensity score-based matching and overlap weighting. Association between intravenous hydration and outcomes was analyzed using logistic regression.

RESULTS

In total, 794 patients were included in the study, with 284 receiving intravenous hydration, and 510 not. After 1:1 propensity score matching, 210 pairs were generated. No significant differences were found in the outcomes between the intravenous hydration and no intravenous hydration groups: PC-AKI by KDIGO, 25.2% vs 24.8% (odds ratio (OR), 0.93; 95% confidence interval (CI), 0.57-1.50); PC-AKI by ESUR, 31.0% vs 25.2% (OR, 1.34; 95% CI, 0.86-2.08); chronic dialysis at discharge, 4.3% vs 3.3% (OR, 1.56; 95% CI, 0.56-4.50); in-hospital mortality, 1.9% vs 0.5% (OR, 4.08; 95% CI, 0.58-81.08). Overlap propensity score-weighted analysis also showed no significant effects of intravenous hydration on the incidences of the post-contrast outcomes.

CONCLUSIONS

Intravenous hydration was not associated with lower risks of PC-AKI, chronic dialysis at discharge, and in-hospital mortality in patients with eGFR < 30 mL/min/1.73 m2 undergoing intravenous administration of ICM.

CLINICAL RELEVANCE STATEMENT

This study provides new evidence in supporting that intravenous hydration is not beneficial to patients with eGFR < 30 mL/min/1.73 m2 before and after intravenous administration of iodinated contrast media.

KEY POINTS

• Intravenous hydration before and after intravenous administration of ICM is not associated with lower risks in PC-AKI, chronic dialysis at discharge, and in-hospital mortality in patients with eGFR < 30 mL/min/1.73 m2. • Withholding intravenous hydration may be considered in patients with eGFR < 30 mL/min/1.73 m2 around intravenous administration of ICM.

Fluid administration strategies for the prevention of contrast-associated acute kidney injury

PURPOSE OF REVIEW

The known timing of contrast media exposure in patients identified as high-risk for contrast-associated acute kidney injury (CA-AKI) enables the use of strategies to prevent this complication of intravascular contrast media exposure. Although multiple preventive strategies have been proposed, periprocedural fluid administration remains as the primary preventive strategy. This is a critical review of the current evidence evaluating a variety of fluid administration strategies in CA-AKI.

RECENT FINDINGS

Fluid administration strategies to prevent CA-AKI include comparisons of intravenous (i.v.) to no fluid administration, different fluid solutions, duration of fluid administration, oral hydration, left ventricular end diastolic-pressure guided fluid administration and forced diuresis techniques.

SUMMARY

Despite an abundance of fluid administration trials, it is difficult to make definitive recommendations about preventive fluid administration strategies due to low scientific quality of published studies. The literature supports use of i.v. compared with no fluid administration, especially in high-risk patients undergoing intra-arterial contrast media exposure. Use of isotonic saline is recommended over 0.45% saline or isotonic sodium bicarbonate. Logistical considerations support shortened over longer i.v. fluid administration strategies, despite an absence of evidence of equivalent efficacy. Current literature does not support oral hydration for high-risk patients. The use of tailored fluid administration in heart failure patients and forced diuresis with matching fluid administration are promising new fluid administration strategies.

Long-term safety of withholding standard prophylaxis in patients with moderate chronic kidney disease

In the latest ESUR contrast media guidelines, standard prophylaxis is no longer recommended for patients with moderate chronic kidney disease (CKD). In the absence of solid evidence, guideline updates are often based on indirect evidence and expert opinion. Likewise, evidence supporting the withdrawal of standard prophylaxis in moderate CKD patients was scarce and mostly indirect, but did include one randomised controlled trial evaluating guideline-recommended standard prophylactic intravenous hydration against a group receiving no prophylaxis (A MAastricht Contrast-Induced Nephropathy Guideline (AMACING) trial). Since then, benefits of the updated guideline recommendation for patient and hospital burden have been numerated and were shown to be substantial. The current special report provides data on long-term safety from the AMACING randomised controlled trial. KEY POINTS: • In the latest version of ESUR clinical practice guidelines for safe use of contrast media, standard prophylaxis is no longer recommended for patients with moderate chronic kidney disease. • Benefits of this change in recommendations for patient and hospital burden have been numerated. The current report provides data on long-term safety from the AMACING randomised controlled trial. • No disadvantage of withholding prophylaxis could be discerned. Results suggest that, in this population, underlying disease is more relevant for survival and prognosis than contrast administration itself.

Efficacy of brain natriuretic peptide vs. nicorandil in preventing contrast-induced nephropathy: a network meta-analysis

This study aimed to conduct a network meta-analysis (NMA) to compare the efficacy of brain natriuretic peptide (BNP) vs nicorandil for preventing contrast-induced nephropathy (CIN). Databases of Pubmed, Cochrane, Embase, Web of Science were searched by keywords for eligible studies of randomized controlled trials investigating different agents (BNP, nicorandil, nitroglycerin, intravenous saline) for preventing CIN. The outcomes included a change in serum creatinine level at 48 h and the incidence of CIN after percutaneous coronary intervention (PCI) or coronary angiography (CAG). A total of 13 studies with 3,462 patients were included. Compared with intravenous saline alone, except for nitroglycerin (odds ratio [OR]: 1.02, 95% CI [0.36-2.88]), the other drugs significantly reduced the CIN incidence with OR of 0.35 (95% CI [0.24-0.51]) for BNP, 0.52 (0.29, 0.94) for usual-dose nicorandil, 0.28 (0.19, 0.43) for double-dose nicorandil. BNP and double-dose nicorandil significantly decreased the change of serum creatinine (SCr) levels with mean difference (MD) of -6.98, (-10.01, -3.95) for BNP, -8.78, (-11.63, -5.93) for double-dose nicorandil. No significant differences were observed in the change of SCr levels for nitroglycerin (-4.97, [-11.46, 1.52]) and usual-dose nicorandil (-2.32, [-5.52, 0.89]) compared with intravenous saline alone. For double-dose nicorandil, the CIN incidence and the change of SCr level in group of 4-5 days treatment course were more than group of less than or equal to 24 h treatment course (OR of 1.48, [0.63-3.46] and MD of 2.48, [-1.96, 6.91]). In conclusion, BNP and double-dose nicorandil can have effects on preventing the incidence of CIN and double-dose nicorandil performed better than BNP. In double-dose nicorandil groups, a course of less than or equal to 24 h before and after procedure performed with better efficacy than a course of 4-5 days.

Korean Clinical Practice Guidelines for Adverse Reactions to Intravenous Iodinate and MRI-Gadolinium Contrast Agents: Revised Clinical Consensus and Recommendations (3rd Edition, 2022)

대한영상의학회 진료지침위원회는 기존의 2016년 진료지침을 개정하여 ‘주사용 요오드화 조영제 및 MRI용 가돌리늄 조영제 유해 반응에 대한 한국 임상진료지침: 개정된 임상적 합의 및 권고안(2022년 제3판)’을 제작하였다. 대한영상의학회와 대한천식알레르기학회, 대한신장학회에세 추천 및 승인된 전문가 위원들이 함께 참여하였고, 전문가 합의 또는 체계적 문헌 고찰을 기반으로, 조영제를 사용 시 감염관리를 위한 자동주입기 및 연결선에 대한 기술과 요요드화 조영제에 대한 급성 유해반응 및 신장 유해반응에 대한 내용들을 수정 및 추가하였다. 이에 개정된 내용을 소개하고자 한다.

Computed Tomography Angiography of the Aorta-Optimization of Automatic Tube Voltage Selection Settings to Reduce Radiation Dose or Contrast Medium in a Prospective Randomized Trial

OBJECTIVES

The aim of this study was to compare the image quality of low-kV protocols with optimized automatic tube voltage selection (ATVS) settings to reduce either radiation dose or contrast medium (CM) with that of a reference protocol for computed tomography angiography (CTA) of the thoracoabdominal aorta.

MATERIALS AND METHODS

In this institutional review board-approved, single-center, prospective randomized controlled trial, 126 patients receiving CTA of the aorta were allocated to one of three computed tomography protocols: (A) reference protocol at 120 kVp and standard weight-adapted CM dose; (B) protocol at 90 kVp, reduced radiation and standard CM dose; and (C) protocol at 90 kVp, standard radiation and reduced CM dose. All three protocols were performed on a third-generation dual-source computed tomography scanner using the semimode of the ATVS system. The image-task-dependent optimization settings of the ATVS (slider level) were adjusted to level 11 (high-contrast task) for protocols A and B and level 3 (low-contrast task) for protocol C. Radiation dose parameters were assessed. The contrast-to-noise ratios (CNRs) of protocols B and C were tested for noninferiority compared with A. Subjective image quality was assessed using a 5-point Likert scale.

RESULTS

Size-specific dose estimate was 34.3% lower for protocol B compared with A (P < 0.0001). Contrast medium was 20.2% lower for protocol C compared with A (P < 0.0001). Mean CNR in B and C was noninferior to protocol A (CNR of 30.2 ± 7, 33.4 ± 6.7, and 30.5 ± 8.9 for protocols A, B, and C, respectively). There was no significant difference in overall subjective image quality among protocols (4.09 ± 0.21, 4.03 ± 0.19, and 4.08 ± 0.17 for protocols A, B, and C, respectively; P = 0.4).

CONCLUSIONS

The slider settings of an ATVS system can be adjusted to optimize either radiation dose or CM at noninferior image quality in low-kV CTA of the aorta. This optimization could be used to extend future ATVS algorithms to take clinical risk factors like kidney function of individual patients into account.

Post-Contrast Acute Kidney Injury and Intravenous Prophylactic Hydration: An Update

BACKGROUND

 Despite tremendous improvement in molecular properties over the last century, intravascular injection of iodinated contrast material may still have systemic and hemodynamic consequences. Patients with pre-existing renal insufficiency may be at risk for acute kidney injury, which may be associated with an increased risk of the need for dialysis and mortality in the long term. Many questions as to the physiological pathways, optimal definition, and incidence of contrast-induced acute kidney injury remain open. These uncertainties are reflected in the changing landscape of this field in terms of nomenclature, research, and clinical practice.

METHODS

 Clinical practice guidelines for the prevention of post-contrast acute kidney injury all recommend giving prophylaxis in the form of intravenous hydration to high-risk patients. Solid evidence for this strategy is lacking. This article gives an overview of the changing landscape of post-contrast acute kidney injury and prophylactic intravenous hydration, with the aim of supporting informed decision-making in clinical practice.

RESULTS

 Recent data have caused a shift in guideline recommendations: 90 % of patients formerly considered high-risk for contrast-induced acute kidney injury no longer qualify for prophylaxis. The remaining high-risk patients, with severe chronic kidney disease, represent a vulnerable population for whom intravenous hydration may provide some benefits but also carries risk.

CONCLUSION

 Intravenous hydration may benefit 'new' high-risk patients. However, it also confers risk. A dual approach to screening patients will help avoid this risk in clinical practice.

KEY POINTS

  · Intravenous hydration is the cornerstone for preventing contrast-induced acute kidney injury. · Solid evidence is lacking; recent data caused a shift in guideline recommendations. · Intravenous hydration may benefit 'new' high-risk patients with severe chronic kidney disease; however, it also confers risk. · A dual approach to screening patients will help avoid this risk in clinical practice.

CITATION FORMAT

· Nijssen E, Rennenberg R, Nelemans P et al. Post-Contrast Acute Kidney Injury and Intravenous Prophylactic Hydration: An Update. Fortschr Röntgenstr 2021; 193: 151 - 159.

Advances in the pathogenesis and prevention of contrast-induced nephropathy

With the increasing application of medical imaging contrast materials, contrast-induced nephropathy has become one of the leading causes of iatrogenic renal insufficiency. The underlying mechanism is associated with renal medullary hypoxia, direct toxicity of contrast agents, oxidative stress, apoptosis, immune/inflammation and epigenetic regulation in contrast-induced nephropathy. Up to date, there is no effective therapy for contrast-induced nephropathy, and thus risk predication and effective preventive strategies are keys to reduce the occurrence of contrast-induced nephropathy. It was found that the proper use of contrast medium, personalized hydration, and high-dose statins may reduce the occurrence of contrast-induced nephropathy, while antioxidants have not shown significant therapeutic benefits. Additionally, the role of remote ischemia preconditioning and vasodilators in the prevention of contrast-induced nephropathy needs further study. This review aims to discuss the incidence, pathogenesis, risk prediction, and preventive strategies for contrast-induced nephropathy.

Hydration: Intravenous and Oral: Approaches, Principals, and Differing Regimens: Is It What Goes in or What Comes Out That Is Important?

The literature (in English) was accessed to review the evidence that administration of fluids is protective of contrast-associated acute kidney injury (CA-AKI). The evidence was evaluated with the intent of understanding mechanisms of protection. Prospective randomized trials comparing oral versus intravenous fluid, sodium chloride versus no intravenous fluid, sodium bicarbonate versus sodium chloride, and forced matched hydration versus intravenous sodium chloride provided the data. In general, the more fluid administered, the lower the incidence of CA-AKI. However, understanding the mechanism of this beneficial effect suggests that it is the urine output that most directly affects the incidence of CA-AKI.

Use of Intravenous Iodinated Contrast Media in Patients with Kidney Disease: Consensus Statements from the American College of Radiology and the National Kidney Foundation

Intravenous iodinated contrast media are commonly used with CT to evaluate disease and to determine treatment response. The risk of acute kidney injury (AKI) developing in patients with reduced kidney function following exposure to intravenous iodinated contrast media has been overstated. This is due primarily to historic lack of control groups sufficient to separate contrast-induced AKI (CI-AKI; ie, AKI caused by contrast media administration) from contrast-associated AKI (CA-AKI; ie, AKI coincident to contrast media administration). Although the true risk of CI-AKI remains uncertain for patients with severe kidney disease, prophylaxis with intravenous normal saline is indicated for patients who have AKI or an estimated glomerular filtration rate less than 30 mL/min/1.73 m² who are not undergoing maintenance dialysis. In individual high-risk circumstances, prophylaxis may be considered in patients with an estimated glomerular filtration rate of 30-44 mL/min/1.73 m² at the discretion of the ordering clinician. This article is a simultaneous joint publication in Radiology and Kidney Medicine. The articles are identical except for stylistic changes in keeping with each journal's style. Either version may be used in citing this article.

Impact on clinical practice of updated guidelines on iodinated contrast material: CINART

Objective

Guidelines on safe use of iodinated contrast material recommend intravenous prophylactic hydration to prevent post-contrast adverse (renal) effects. Recently, guidelines have been updated and standard prophylaxis is no longer recommended for the majority of patients. The current study aims to evaluate the consequences for clinical practice of the updated guidelines in terms of complications, hospitalisations, and costs.

Methods

The Contrast-Induced Nephropathy After Reduction of the prophylaxis Threshold (CINART) project is a retrospective observational study. All elective procedures with intravascular iodinated contrast administration at Maastricht University Medical Centre (UMC+) in patients aged > 18 years, formerly eligible for prophylaxis (eGFR 30–44 ml/min/1.73 m² or eGFR 45–59 ml/min/1.73 m² in combination with diabetes or > 1 predefined risk factor), and currently eligible for prophylaxis (eGFR < 30 ml/min/1.73 m²) were included. Data were used to calculate relative reductions in complications, hospitalisations, and costs associated with standard prophylactic intravenous hydration. CINART is registered with Clinicaltrials.gov: NCT03227835.

Results

Between July 1, 2017, and July 1, 2018, 1992 elective procedures with intravascular iodinated contrast in patients formerly and currently eligible for prophylaxis were identified: 1808 in patients formerly eligible for prophylaxis and 184 in patients currently eligible for prophylaxis. At Maastricht UMC+, guideline updates led to large relative reductions in numbers of complications of prophylaxis (e.g. symptomatic heart failure; − 89%), extra hospitalisations (− 93%), and costs (− 91%).

Conclusion

Guideline updates have had a demonstrable impact on daily clinical practice benefiting patient, hospital, and health care budgets. Clinical practice varies between institutions and countries; therefore, a local estimation model is provided with which local impact on costs, hospitalisations, and complications can be calculated.

Key Points

• Clinical practice guidelines recommend prophylactic intravenous hydration to prevent post-contrast adverse outcomes such as contrast-induced acute kidney injury.

• Clinical practice guidelines have recently been updated, and standard prophylaxis is no longer recommended for the majority of patients.

• The guideline updates have a large impact on daily clinical practice: relative reductions at Maastricht UMC+ were − 89% prophylaxis complications, − 93% hospitalisations, and − 91% costs, and similar reductions are expected for Dutch and adherent European medical centres.

Electronic supplementary material

The online version of this article (10.1007/s00330-020-06719-7) contains supplementary material, which is available to authorized users.

Use of Intravenous Iodinated Contrast Media in Patients With Kidney Disease: Consensus Statements from the American College of Radiology and the National Kidney Foundation

Intravenous iodinated contrast media are commonly used with CT to evaluate disease and to determine treatment response. The risk of acute kidney injury (AKI) developing in patients with reduced kidney function following exposure to intravenous iodinated contrast media has been overstated. This is due primarily to historic lack of control groups sufficient to separate contrast-induced AKI (CI-AKI; ie, AKI caused by contrast media administration) from contrast-associated AKI (CA-AKI; ie, AKI coincident to contrast media administration). Although the true risk of CI-AKI remains uncertain for patients with severe kidney disease, prophylaxis with intravenous normal saline is indicated for patients who have AKI or an estimated glomerular filtration rate less than 30 mL/min/1.73 m² who are not undergoing maintenance dialysis. In individual high-risk circumstances, prophylaxis may be considered in patients with an estimated glomerular filtration rate of 30-44 mL/min/1.73 m² at the discretion of the ordering clinician.

Is There a Nonlinear Relationship between Serum Uric Acid and Lipids in a Hypertensive Population with eGFR ≥30 ml/min/1.73 m2? Findings from the China Hypertension Registry Study

BACKGROUND

Evidence regarding the nonlinear relationship between serum uric acid (SUA) and blood lipids in Chinese population with hypertension is limited. Therefore, the present study aimed to investigate whether there is a nonlinear association between SUA and lipids in Chinese hypertensive population with an estimated glomerular filtration rate (eGFR) ≥30 ml/min/1.73 m².

METHODS

A total of 13,355 hypertensive participants with eGFR ≥30 ml/min/1.73 m² were selected from the Chinese Hypertension Registry Study. Multivariate linear regression was used to examine the linear relationship between SUA and lipids. Smooth curve fitting (penalized spline method) and threshold saturation effects were used to analyze the nonlinear association between SUA and lipids.

RESULTS

In the fully adjusted model, the results showed a positive correlation between SUA and TG (β = 0.15; 95% CI: 0.14, 0.16) and LDL-C (β = 0.06; 95% CI: 0.05, 0.07), respectively. However, the relationship between SUA and HDL-C was nonlinear. The inflection point of SUA was 7.24 mg/dL. On the left side of the inflection point (<7.24 mg/dL), SUA was negatively associated with HDL-C (β = -0.02; 95% CI -0.02, -0.01). On the right side of the inflection point (≥7.24 mg/dL), SUA was not related to HDL-C (β = 0.01; 95% CI -0.01, 0.02).

CONCLUSION

After adjusting for all covariates, SUA was positively associated with TG and LDL-C. The relationship between SUA and HDL-C was nonlinear. The negative correlation between SUA and HDL-C only existed when the SUA was less than 7.24 mg/dL in a hypertensive population with eGFR ≥30 ml/min/1.73 m².