Prophylactic hemodialysis does not prevent contrast-induced nephropathy after cardiac catheterization in patients with chronic renal insufficiency

Navigating nephrotoxic waters: A comprehensive overview of contrast-induced acute kidney injury prevention

Contrast-induced acute kidney injury (CI-AKI) is the third leading cause of acute kidney injury deriving from the intravascular administration of contrast media in diagnostic and therapeutic procedures and leading to longer in-hospital stay and increased short and long-term mortality. Its pathophysiology, although not well-established, revolves around medullary hypoxia paired with the direct toxicity of the substance to the kidney. Critically ill patients, as well as those with pre-existing renal disease and cardiovascular comorbidities, are more susceptible to CI-AKI. Despite the continuous research in the field of CI-AKI prevention, clinical practice is based mostly on periprocedural hydration. In this review, all the investigated methods of prevention are presented, with an emphasis on the latest evidence regarding the potential of RenalGuard and contrast removal systems for CI-AKI prevention in high-risk individuals.

Contrast-induced acute kidney injury and its contemporary prevention

The complexity and application range of interventional and diagnostic procedures using contrast media (CM) have recently increased. This allows more patients to undergo procedures that involve CM administration. However, the intrinsic CM toxicity leads to the risk of contrast-induced acute kidney injury (CI-AKI). At present, effective therapy of CI-AKI is rather limited. Effective prevention of CI-AKI therefore becomes crucially important. This review presents an in-depth discussion of CI-AKI incidence, pathogenesis, risk prediction, current preventive strategies, and novel treatment possibilities. The review also discusses the difference between CI-AKI incidence following intraarterial and intravenous CM administration. Factors contributing to the development of CI-AKI are considered in conjunction with the mechanism of acute kidney damage. The need for ultimate risk estimation and the prediction of CI-AKI is stressed. Possibilities of CI-AKI prevention is evaluated within the spectrum of existing preventive measures aimed at reducing kidney injury. In particular, the review discusses intravenous hydration regimes and pre-treatment with statins and N-acetylcysteine. The review further focuses on emerging alternative imaging technologies, alternative intravascular diagnostic and interventional procedures, and new methods for intravenous hydration guidance; it discusses the applicability of those techniques in complex procedures and their feasibility in current practise. We put emphasis on contemporary interventional cardiology imaging methods, with a brief discussion of CI-AKI in non-vascular and non-cardiologic imaging and interventional studies.

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.

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.

The Prevention and Management of Contrast-induced Acute Kidney Injury: A Mini-review of the Literature

Contrast-induced acute kidney injury, also called contrast-induced nephropathy, is one of the main causes of acute renal failure/acute kidney injury (AKI) in hospitalized patients within 48 to 72 hours of contrast media administration during various radiologic procedures. Several factors can be responsible for contrast-induced acute tubular necrosis (ATN); however, patient and procedure-related factors play the lead role in determining the development of contrast-induced nephropathy. There is no definitive treatment and hydration remains the mainstay preventive strategy. This article will review the incidence, criteria for definitive diagnosis, and an effective approach on how to prevent contrast-induced nephropathy in a clinical setup.

Radial access protects from contrast media induced nephropathy after cardiac catheterization procedures

OBJECTIVES

To assess, whether cardiac catheterization via radial access prevents contrast-induced nephropathy.

BACKGROUND

Contrast-induced nephropathy (CIN) is a major clinical problem which accounts for more than 10% of acute kidney injury cases in hospitalized patients. Protective measures such as the infusion of isotonic saline solution or acetylcysteine have not consistently been proven to prevent acute kidney injury (AKI). However, there is growing evidence that radial access for coronary angiography and coronary intervention is associated with a lower incidence of AKI compared to femoral access.

METHODS AND RESULTS

In a retrospective monocentric analysis, 2937 patients that had undergone cardiac catheterization were examined. Up to 2013, coronary intervention was performed primarily via the femoral artery in our hospital; thereafter, interventions were primarily done via the radial artery. In the cohort under study, 1141 patients had received catheterization using the radial access while 1796 were examined via the femoral artery. No significant differences were found in the two groups regarding the amount of iodinated contrast medium applied [femoral group: 180 (120-260) ml; radial group: 180 (120-250) ml; P = 0.438]. A total of 400 (13.6%) patients developed acute kidney injury (AKI) after cardiac catheterization (85.3% AKI stage 1; 12.8% AKI stage 2; 2% AKI stage 3). AKI was significantly less frequent in patients that had received radial access compared to patients with femoral access (10.1 vs. 15.9%, P < 0.001). Multivariate regression analysis showed that patient age (1.03/year; 95% CI 1.02-1.04/year; P < 0.001), the amount of contrast media applied (OR 1.003/ml; 95% CI 1.002-1.004/ml; P < 0.001), acute coronary syndrome (OR 2.01, 95% CI 1.52-2.66; P < 0.001), CKD (OR 1.62, 95% CI 1.50-1.70; P < 0.001), pre-existing heart failure (OR 1.27, 95% CI 1.00-1.42 P = 0.007), previous myocardial infarction (OR 1.34, 95% CI 1.15-1.49; P = 0.001), diabetes (OR 1.25, 95% CI 1.04-1.41; P = 0.020) and serum creatinine before the procedure (1.45/mg/dl; 95% CI 1.24-1.69/mg/dl; P < 0.001) were important risk factors for the occurrence of AKI. Our analysis points to a significant risk reduction using radial access (OR 0.65; 95% CI 0.51-0.83; P < 0.001). Interestingly, this reduction in risk was also evident in patients with CKD (OR 0.59; 95% CI 0.41-0.87; P = 0.007). The superiority of radial access was particularly obvious in the subgroup of patients with acute coronary syndrome (13.1% AKI in the radial access group vs. 23.6% AKI in the femoral access group, OR 0.52; 95% CI 0.34-0.81; P = 0.003).

CONCLUSION

Our study shows that cardiac catheterization using radial access bears significantly lower risk of AKI than cardiac catheterization via femoral access. The advantage of radial access in acute coronary syndrome regarding morbidity and mortality could partly be explained by the here demonstrated reduced risk for AKI. Thus, radial access should be preferred in patients at risk for AKI.

Repeatability of Non-Contrast-Enhanced Lower-Extremity Angiography Using the Flow-Spoiled Fresh Blood Imaging

Purpose

The aim of this study was to prospectively evaluate the repeatability of non–contrast-enhanced lower-extremity magnetic resonance angiography using the flow-spoiled fresh blood imaging (FS-FBI).

Methods

Forty-three healthy volunteers and 15 patients with lower-extremity arterial stenosis were recruited in this study and were examined by FS-FBI. Digital subtraction angiography was performed within a week after the FS-FBI in the patient group. Repeatability was assessed by the following parameters: grading of image quality, diameter and area of major arteries, and grading of stenosis of lower-extremity arteries. Two experienced radiologists blinded for patient data independently evaluated the FS-FBI and digital subtraction angiography images. Intraclass correlation coefficients (ICCs), sensitivity, and specificity were used for statistical analysis.

Results

The grading of image quality of most data was satisfactory. The ICCs for the first and second measures were 0.792 and 0.884 in the femoral segment and 0.803 and 0.796 in the tibiofibular segment for healthy volunteer group, 0.873 and 1.000 in the femoral segment, and 0.737 and 0.737 in the tibiofibular segment for the patient group. Intraobserver and interobserver agreements on diameter and area of arteries were excellent, with ICCs mostly greater than 0.75 in the volunteer group. For stenosis grading analysis, intraobserver ICCs range from 0.784 to 0.862 and from 0.778 to 0.854, respectively. Flow-spoiled fresh blood imaging yielded a mean sensitivity and specificity to detect arterial stenosis or occlusion of 90% and 80% for femoral segment and 86.7% and 93.3% for tibiofibular segment at least.

Conclusions

Lower-extremity angiography with FS-FBI is a reliable and reproducible screening tool for lower-extremity atherosclerotic disease, especially for patients with impaired renal function.

Contrast-induced Nephropathy

Contrast-induced nephropathy (CIN) is a serious complication of angiographic procedures resulting from the administration of contrast media (CM). It is the third most common cause of hospital acquired acute renal injury and represents about 12% of the cases. CIN is defined as an elevation of serum creatinine (Scr) of more than 25% or ≥0.5 mg/dl (44 μmol/l) from baseline within 48 h. More sensitive markers of renal injury are desired, therefore, several biomarkers of tubular injury are under evaluation. Multiple risk factors may contribute to the development of CIN; these factors are divided into patient- and procedure-related factors. Treatment of CIN is mainly supportive, consisting mainly of careful fluid and electrolyte management, although dialysis may be required in some cases. The available treatment option makes prevention the corner stone of management. This article will review the recent evidence concerning CIN incidence, diagnosis, and prevention strategies as well as its treatment and prognostic implications.

Nonenhanced renal MR angiography using steady-state free precession (SSFP) and time-spatial labeling inversion pulse (Time-SLIP): repeatability and comparison of different tagging location

PURPOSE

To prospectively determine the repeatability of noncontrast-enhanced renal arterial angiography with steady-state free precession (SSFP) and time-spatial labeling inversion pulse (Time-SLIP), and to compare the visibility of renal artery and its branches when different locations of tagging pulse were placed.

METHODS

Thirty-six young healthy volunteers were enrolled in this study and were twice examined by noncontrast-enhanced renal arterial angiography with SSFP and Time-SLIP in 1.5T MR scanner. Measurement error and repeatability were assessed for each of the five major parameters [vessel-to-kidney ratio (VKR), grade of renal arterial branching, grading of image quality, diameter and area of the main renal artery] using the Bland-Altman plot. Two independent observers recorded the values of the parameters; Inter- and intra-observer agreement was assessed using the intraclass correlation coefficients (ICCs). The same parameters, acquired at the tagging pulse placed just above the superior poles of both kidneys or closer to the main renal arteries, were compared using the Wilcoxon signed-rank test.

RESULTS

Grading of arterial branching by the Time-SLIP SSFP was satisfactorily reproducible with the mean score of greater 3.83 indicating the visibility of branches within the renal parenchyma. The image quality was excellent for Segment I (the main trunk of renal artery) and good for Segment II (segmental branches pre renal parenchyma) and III (vessels within the renal parenchyma) with a satisfying repeatability between two examinations and a good inter- and intra-observer agreement. The ICCs for the inter- and intra-observer measurements of both diameter and area of the main arteries ranged from 0.781 to 0.934, indicating very good agreement. The repeatability of VKR was poor between the two examinations and at the two different tagging pulse locations. The position of tagging pulse in the origination of the main renal arteries was better than in the superior poles of kidneys as it provided a better visualization of arterial branches.

CONCLUSION

Noncontrast-enhanced renal artery angiography with SSFP and Time-SLIP yields reliable and reproducible visualization of normal renal arteries. Localization of the tagging pulse closer to the main renal arteries provides better visibility of renal artery and its branches than the tag placement just above the superior poles of both kidneys.

Safety margin of minimized contrast volume during percutaneous coronary intervention in patients with chronic kidney disease

Maximum allowable contrast dose (MACD) calculated as body weight × 5/serum creatinine has been a standard contrast dye volume (CV) used to decrease contrast-induced acute kidney injury. Recent advances in intravascular ultrasound-guided percutaneous coronary intervention (PCI) can dramatically minimize CV. The safe threshold when using an extremely low-dose CV is unknown. This study was designed as a multicenter, retrospective study of chronic kidney disease (CKD) patients with estimated glomerular filtration rate (eGFR) <30 ml/min/1.73 m(2) undergoing elective PCI. We divided the patients into three groups according to following criteria: (1) low dose, CV/eGFR ratio <1.0; (2) medium dose, CV/eGFR ratio ≥1 and <MACD; and (3) high dose, CV ≥MACD. A total of 100 patients were enrolled. Average age was 74 ± 8 years, 64 % were male and 48 % were diabetic. Mean baseline eGFR was 22.8 ± 6.0 ml/min/1.73 m(2). CV in the three groups was 15 ± 6 ml (n = 18), 69 ± 39 ml (n = 47) and 224 ± 99 ml (n = 35), respectively. The incidences of CI-AKI were 0, 11 and 23 %, respectively (p = 0.02). All-cause death or introduction of maintenance hemodialysis at 1 year was 0, 13.8 and 31 %, respectively (p = 0.01). Extreme reduction of CV to a CV/eGFR ratio <1.0 may reduce CI-AKI and achieve better clinical outcomes following PCI in patients with severe CKD.

Renal replacement therapies for prevention of radiocontrast-induced nephropathy: a systematic review

BACKGROUND

Radiocontrast-induced nephropathy (RCIN) is an important cause of acute kidney injury, increasing in-hospital and long-term mortality. It is controversial whether prophylactic renal replacement therapy (RRT) may reduce a patient's risk of RCIN when compared with standard medical therapy (SMT).

METHODS

We searched through PubMed and bibliographies of retrieved articles. Published studies of RRT for RCIN prevention in patients receiving radiocontrast were included. The primary endpoint was RCIN incidence, defined as an increase in serum creatinine ≥0.5 mg/dL. Results were combined on the risk ratio (RR) scale. Random-effects models were used. Sensitivity analyses were defined a priori to evaluate the effects of RRT modality, study design, and sample size.

RESULTS

Nine randomized controlled and 2 nonrandomized trials were included (n = 1010 patients); 8 studies used hemodialysis (HD) and 3 used hemofiltration or hemodiafiltration. Nine studies had data for primary endpoint; RCIN incidence was 23.3% in the RRT group and 21.2% in SMT. RRT did not decrease RCIN incidence compared with SMT (risk ratio [RR] 1.02; 95% confidence interval [CI], 0.54-1.93); however, intertrial heterogeneity was high. In sensitivity analyses, limiting to only HD studies significantly reduced heterogeneity. HD appeared to increase RCIN risk (RR 1.61; 95% CI, 1.13-2.28) and had no effect on need for permanent RRT or progression to end-stage renal disease (RR 1.47; 95% CI, 0.56-3.89).

CONCLUSION

In this updated meta-analysis, periprocedural RRT did not decrease the incidence of RCIN compared with SMT. HD appears to actually increase RCIN risk.

Incidence of and risk factors for contrast-induced nephropathy after cardiac catheterization in Japanese patients

BACKGROUND

Contrast-induced nephropathy (CIN) is the third leading cause of all hospital-acquired renal insufficiency, accounting for 10%, and is associated with increased long-term mortality. The incidence of and risk factors for CIN after cardiac catheterization in Japanese patients are, however, unknown at present.

METHODS AND RESULTS

The 1,157 consecutive patients who underwent cardiac catheterization at Kyoto University Hospital from January 2003 to December 2004 were retrospectively examined. The incidence of CIN defined as an absolute increase in serum creatinine (SCr) > or =0.5 mg/dl, a relative > or =25% increase in SCr, and either an absolute or relative increase after cardiac catheterization were 4.0%, 13.8%, and 13.9%, respectively. Multivariate logistic models revealed that preexisting renal insufficiency and the use of high-volume contrast were independently associated with an absolute increase in SCr > or =0.5 mg/dl. Female gender, underweight, and high-volume contrast usage were independently associated with a relative > or =25% increase and either an absolute or relative increase in SCr.

CONCLUSIONS

Although the incidence of and risk factors for CIN after cardiac catheterization varied in the study population according to the definition of CIN, careful attention should be paid to patients who have risk factors identified by each definition of CIN.

The role of dialysis in contrast-induced nephropathy: doubts and certainties

Over past years, there has been a progressive increase in percutaneous endovascular procedures in patients with chronic renal disease, owing to the high incidence of vascular disease, particularly coronary artery disease, in this population. The use of contrast media may further worsen renal function in such patients, in some cases even accelerating the progression towards end-stage renal failure, and may increase patient morbidity and mortality. In this review, we discuss the role of dialysis in preventing contrast-induced nephropathy as well as present indications to its use in patients already on dialysis treatment undergoing diagnostic or therapeutic procedures with contrast medium injection.