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

Role of Invasive Strategy for Non-ST-Elevation Myocardial Infarction in Patients With Chronic Kidney Disease: A Systematic Review and Meta-Analysis

Patients with chronic kidney disease (CKD) have traditionally been excluded from randomized trials. We aimed to compare percutaneous coronary intervention versus conservative management, and early intervention (EI; within 24 hours of admission) versus delayed intervention (DI; after 24 to 72 hours of admission) in patients with non-ST-segment elevation myocardial infarction (NSTEMI) and concomitant CKD. An electronic literature search was performed to search for studies comparing invasive management to conservative management or EI versus DI in patients with NSTEMI with CKD. The primary outcome was all-cause mortality; secondary outcomes were acute kidney injury (AKI) or dialysis, major bleeding, and recurrent MI. Hazard ratios (HRs) for the primary outcome and odds ratios for secondary outcomes were pooled in random-effects meta-analyses. Eleven studies (140,544 patients) were analyzed. Invasive management was associated with lower mortality than conservative management (HR 0.62, 95% confidence interval 0.57 to 0.67, p <0.001, I2 = 47%), with consistent benefit across all CKD stages, except CKD 5. There was no significant mortality difference between EI and DI, but subgroup analyses showed significant benefit for EI in stage 1 to 2 CKD (HR 0.75, 95% confidence interval 0.58 to 0.97, p = 0.03, I2 = 0%), with no significant difference in stage 3 and 4 to 5 CKD. Invasive strategy was associated with higher odds of AKI or dialysis and major bleeding, but lower odds of recurrent MI compared with conservative management. In conclusion, in patients with NSTEMI and CKD, an invasive strategy is associated with significant mortality benefit over conservative management in most patients with CKD, but at the expense of higher risk of AKI and bleeding. EI appears to benefit those with early stages of CKD. Trial Registration: PROSPERO CRD42023405491.

A Simple Strategy to Reduce Contrast Media Use and Risk of Contrast-Induced Renal Injury during PCI: Introduction of an "Optimal Contrast Volume Protocol" to Daily Clinical Practice

Contrast-induced acute kidney injury is the leading cause of iatrogenic acute nephropathy. Development of contrast-induced nephropathy (CIN) increases the risk of adverse long- and short-term patients outcomes, the hospital costs, and length of hospitalization. There are a couple of methods described for CIN prevention (statin prescription, prehydration, contrast media (CM) clearance from the blood system, and decrease amounts of contrast volume). The CM volume to patient's creatinine clearance ratio is the main factor to predict the risk of CIN development. The safe CM to creatinine clearance ratio limits have been established. The usage of CM amount depends on personal operators habits and inside center regulations. There is no standardized contrast usage protocol worldwide. The aim of this study was to establish an easy to use, cheap, and efficient protocol to estimate a personalized safe CM dose limit for every patient based on their kidney function. These limits are announced during the "Time Out" before the procedure. Our study included 519 patients undergoing interventional coronary procedures: 207 patients into the "Optimal Contrast Volume" arm and 312 into the control group. Applying the protocol into a daily clinical practice leads to a significant reduction in CM volume used for all type of procedures and the development of CIN in comparison with a control group.

Intravascular Ultrasound-Guided Percutaneous Coronary Intervention: Practical Application

Why is intravascular ultrasounography (IVUS) highly encouraged for the practical guidance of percutaneous coronary intervention (PCI)? First reason is to understand the mechanism of revascularization. Even if stenoses look similar in angiography, the pathophysiology could be different in each lesion. Second reason is to anticipate possible complications in advance. With prediction and appropriate preparation, most complications can be avoided or managed calmly when they occur. Third reason is to optimize PCI results with interactive IVUS use during the procedure. All these are essential to maximize the results of revascularization while minimizing acute complications, ultimately leading to improved long-term clinical outcomes.

Current clinical use of intravascular ultrasound imaging to guide percutaneous coronary interventions (update)

There are 3 main reasons to promote the practical application of IVUS during PCI. First reason is to understand the mechanism of vessel dilatation. Even if angiographic stenoses are similar, their pathophysiologies are different. It is important to understand what can happen by dilating coronary artery with balloon/stent, and to develop a strategy to achieve the maximum effect. Second reason is to anticipate possible complications and to reduce them in advance. In that case, we can deal with it as calmly as possible. Third reason is to validate the PCI performed. This should lead to further improvements of the procedures, which in turn will lead to improved short- and long-term prognosis. Then, high-quality PCI could be possible. This review summarizes the standard usage of IVUS in routine clinical practice and the use of IVUS in specific situations, especially complex lesions.

New perspectives on contrast-induced nephropathy during coronary interventions

Tweetable abstract To reduce contrast-induced nephropathy as a complication of percutaneous coronary intervention, several thresholds have been proposed, including maximum contrast dose, contrast volume/estimated glomerular filtration rate, revised maximal contrast dose and zero-contrast percutaneous coronary intervention in select patients.

Feasibility, Safety, and Long-Term Outcomes of Zero-Contrast Percutaneous Coronary Intervention in Patients With Chronic Kidney Disease

BACKGROUND

The long-term safety and utility of intravascular ultrasound (IVUS)-guided zero-contrast percutaneous coronary intervention (PCI) in patients with chronic kidney disease (CKD) are unknown.

METHODS AND RESULTS

A total of 698 consecutive patients treated with PCI (1,061 procedures) in our center were studied. Patients with acute coronary syndrome, who are on maintenance hemodialysis, and who had a planned rotational atherectomy were excluded. Finally, they were divided into 2 groups: zero-contrast PCI (n=55, 78 procedures) and conventional PCI (n=462, 670 procedures). After propensity score matching, 50 patients were matched for each group to evaluate long-term outcomes. Primary endpoints were major adverse cardiovascular events (MACE), including all-cause death, non-fatal myocardial infarction (MI), and clinically driven target lesion revascularization. All patients in the zero-contrast PCI group had stage 3-5 CKD with an estimated glomerular filtration rate of 38.3±14.8 mL/min/1.73 m2. Zero-contrast PCI was successful in all 78 procedures without renal events such as acute kidney injury or emergent hemodialysis and procedural complications such as coronary perforation or periprocedural MI. During a follow-up period of 32 months, 7 patients died (1 cardiac, 6 non-cardiovascular), and 4 patients were introduced to renal replacement therapy. The incidence of MACE was similar between the zero-contrast and conventional PCI groups (log-rank, P=0.95).

CONCLUSIONS

IVUS-guided zero-contrast PCI might be safe and feasible in patients with CKD with satisfactory acute and long-term renal and cardiovascular outcomes.

Safe Limits of Contrast Media for Contrast-Induced Nephropathy: A Multicenter Prospective Cohort Study

Background: The safe level of contrast media volume (CV) is an important modifiable risk factor for contrast-induced nephropathy (CIN). The safe limit of CV remains unclear and is limited to single-center studies. Our objective was to determine the association between the ratio of contrast volume-to-glomerular filtration (CV/GFR) and CIN in patients undergoing coronary angiography (CAG) or percutaneous coronary intervention (PCI). Methods: We assessed the association between CV/GFR and the risk of CIN in 4,254 patients undergoing CAG or PCI from the year 2013 to 2016 and enrolled in the REICIN (REduction of rIsk for Contrast-Induced Nephropathy), a prospective, multicenter, observational cohort study. CV/GFR was calculated at the five primary GFR equation. Results: Sixty-nine (1.7%) patients with a median contrast volume-to-chronic kidney disease epidemiology collaboration (CV/CKD-EPI) ratio of 2.16 (1.30-3.93) have suffered from CIN. The CV/CKD-EPI demonstrated the best performance of model fit, discrimination (area under curve = 0.736), calibration, reclassification, and equation conciseness (1 variable). The CV/CKD-EPI ≥1.78 was the statistical significance associated with CIN [adjusted odds ratio, 4.64 (2.84-7.56); p < 0.001]. Furthermore, similar results were found in the subgroup analyses. Conclusions: The CV/CKD-EPI showed the best performance in patients undergoing CAG or PCI. CV/CKD-EPI ≥1.78 could be a more reliable and convenient predictor of CIN. Intraprocedural preventive measures should include a priori calculation of CV/GFR to limit contrast volume.

Revising the Maximal Contrast Dose for Predicting Acute Kidney Injury following Coronary Intervention

INTRODUCTION

The maximal allowable contrast dose (MACD = 5 × body weight/serum creatinine) is an empiric equation that has been used and validated in several studies to mitigate the risk of contrast-induced acute kidney injury (CI-AKI). However, coefficient 5 (referred to as factor K) was empirically devised and never disputed. The aim of this study was to refine the MACD equation for the prediction of CI-AKI following percutaneous coronary interventions (PCIs).

METHODS

This is a single-center, retrospective cohort study of adults undergoing PCI. Electronic medical records were reviewed to identify patients who underwent PCI between 2010 and 2019, derived from the National Cardiovascular Data Registry Cath-PCI registry for our hospital. Factor K (defined as contrast volume × serum creatinine/body weight) was calculated for every patient. A receiver operating characteristic (ROC) curve was constructed, and the Youden index was used to identify the optimal cut-off value for factor K in predicting severe (stages 2-3) CI-AKI.

RESULTS

Of the 3,506 patients undergoing PCI, 255 (7.2%) developed CI-AKI, and 68 (26.7%) of the 255 experienced severe AKI. Factor K predicted all-stage CI-AKI (area under the ROC curve 0.649; 95% CI 0.611, 0.686) but had better performance for predicting severe (stages 2-3) AKI (0.736; 95% CI 0.674, 0.800). The optimal cut-off value for factor K in predicting severe CI-AKI was 2.5, with a corresponding sensitivity of 68.7% and specificity of 70.5%. On subgroup analyses, optimal cut-off values for factor K for high-risk groups were not significantly different from those of low-risk groups.

CONCLUSION

Our study indicates that factor K in the MACD equation is an independent risk factor for the development of severe CI-AKI, with an optimal cut-off value of 2.5. If our findings are validated, the MACD equation should be revised to incorporate the coefficient of 2.5 instead of 5.

Refining Safe Contrast Limits for Preventing Acute Kidney Injury After Percutaneous Coronary Intervention

Background

Contrast‐associated acute kidney injury (CA‐AKI) is associated with substantial morbidity and may be prevented by using less contrast during percutaneous coronary intervention (PCI). However, tools for determining safe contrast volumes are limited. We developed risk models to tailor safe contrast volume limits during PCI.

Methods and Results

Using data from all PCIs performed at 18 hospitals from January 2015 to March 2018, we developed logistic regression models for predicting CA‐AKI, including simpler models (“pragmatic full,” “pragmatic minimum”) using only predictors easily derivable from electronic health records. We prospectively validated these models using PCI data from April 2018 to December 2018 and compared them to preexisting safe contrast models using the area under the receiver operating characteristic curve (AUC). The model derivation data set included 20 579 PCIs with 2102 CA‐AKI cases. When applying models to the separate validation data set (5423 PCIs, 488 CA‐AKI cases), prior safe contrast limits (5*Weight/Creatinine, 2*CreatinineClearance) were poor measures of safety with accuracies of 53.7% and 56.6% in predicting CA‐AKI, respectively. The full, pragmatic full, and pragmatic minimum models performed significantly better (accuracy, 73.1%, 69.3%, 66.6%; AUC, 0.80, 0.76, 0.72 versus 0.59 for 5 * Weight/Creatinine, 0.61 for 2*CreatinineClearance). We found that applying safe contrast limits could meaningfully reduce CA‐AKI risk in one‐quarter of patients.

Conclusions

Compared with preexisting equations, new multivariate models for safe contrast limits were substantially more accurate in predicting CA‐AKI and could help determine which patients benefit most from limiting contrast during PCI. Using readily available electronic health record data, these models could be implemented into electronic health records to provide actionable information for improving PCI safety.

Long-term renal outcomes after elective percutaneous coronary intervention in patients with advanced renal dysfunction

The aim of the present study was to evaluate the renal outcomes, including the time course of renal function, after elective PCI in patients with advanced renal dysfunction and to assess the predictors of renal dysfunction progression. This is a subanalysis of a previous observational multicenter study that investigated long-term clinical outcomes in patients with advanced renal dysfunction (eGFR < 30 mL/min/1.73 m²), focusing on 151 patients who underwent elective PCI and their long-term renal outcomes. Renal dysfunction progression was defined as a 20% relative decrease in eGFR at 1 year from baseline or the initiation of permanent dialysis within 1 year. Progression of renal dysfunction at 1 year occurred in 42 patients (34.1%). Among patients with renal dysfunction progression, the decrease of renal function from baseline was not observed at 1 month but after 6 months of the index PCI. Baseline eGFR and serum albumin level were significant predictors of renal dysfunction progression at 1 year. Among 111 patients who had not been initiated on dialysis within 1 year, those with renal dysfunction progression had a significantly higher incidence of dialysis initiation more than 1 year after the index PCI than those with preserved renal function (p < 0.001). Among patients with advanced renal dysfunction who underwent elective PCI, 34.1% showed renal dysfunction progression at 1 year. The decrease in renal function was not observed at 1 month but after 6 months of the index PCI in patients with renal dysfunction progression. Furthermore, patients with renal dysfunction progression had poorer long-term renal outcomes.

A Patient Safety Educational Tool for Patients With Chronic Kidney Disease: Development and Usability Study

Background

Chronic kidney disease (CKD) is a health condition that threatens patient safety; however, few interventions provide patient-centered education about kidney-specific safety hazards.

Objective

We sought to develop and test the usability of a mobile tablet–based educational tool designed to promote patient awareness of relevant safety topics in CKD.

Methods

We used plain language principles to develop content for the educational tool, targeting four patient-actionable safety objectives that are relevant for individuals with CKD. These four objectives included avoidance of nonsteroidal anti-inflammatory drugs (NSAIDs); hypoglycemia awareness (among individuals with diabetes); temporary cessation of certain medications during acute volume depletion to prevent acute kidney injury (ie, “sick day protocol”); and contrast dye risk awareness. Our teaching strategies optimized human-computer interaction and content retention using audio, animation, and clinical vignettes to reinforce themes. For example, using a vignette of a patient with CKD with pain and pictures of common NSAIDs, participants were asked “Which of the following pain medicines are safe for Mr. Smith to take for his belly pain?” Assessment methods consisted of preknowledge and postknowledge surveys, with provision of correct responses and explanations. Usability testing of the tablet-based tool was performed among 12 patients with any stage of CKD, and program tasks were rated upon completion as no error, noncritical error (self-corrected), or critical error (needing assistance).

Results

The 12 participants in this usability study were predominantly 65 years of age or older (n=7, 58%) and female (n=7, 58%); all participants owned a mobile device and used it daily. Among the 725 total tasks that the participants completed, there were 31 noncritical errors (4.3%) and 15 critical errors (2.1%); 1 participant accounted for 30 of the total errors. Of the 12 participants, 10 (83%) easily completed 90% or more of their tasks. Most participants rated the use of the tablet as very easy (n=7, 58%), the activity length as “just right” (rather than too long or too short) (n=10, 83%), and the use of clinical vignettes as helpful (n=10, 83%); all participants stated that they would recommend this activity to others. The median rating of the activity was 8 on a scale of 1 to 10 (where 10 is best). We incorporated all participant recommendations into the final version of the educational tool.

Conclusions

A tablet-based patient safety educational tool is acceptable and usable by individuals with CKD. Future studies leveraging iterations of this educational tool will explore its impact on health outcomes in this high-risk population.

Microcatheter injection reduces the amount of contrast medium during middle cerebral artery aneurysm embolization in a patient with chronic kidney disease

We describe a unique technique to reduce the amount of contrast medium by injecting diluted contrast medium from the microcatheter during neurointervention. A patient with severe renal impairment due to polycystic kidney was referred for endovascular surgery for wide-neck middle cerebral artery aneurysm. In order to reduce the amount of contrast medium, contrast medium was injected from the microcatheter placed in the middle cerebral artery during coil embolization; renal function decline was not observed after the procedure. This technique, therefore, reduces the amount of contrast medium and enables one to perform coil embolization safely.

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.

Contrast-Induced Nephropathy and Long-Term Clinical Outcomes Following Percutaneous Coronary Intervention in Patients With Advanced Renal Dysfunction (Estimated Glomerular Filtration Rate <30 ml/min/1.73 m2)

The incidence of contrast-induced nephropathy (CIN) increases with the progression of renal dysfunction. Recent reports have shown that percutaneous coronary intervention (PCI) can be safely performed even in patients with advanced renal dysfunction by appropriate CIN-prevention strategies. However, data are limited regarding the occurrence and prognostic influence of CIN in patients with advanced renal dysfunction. We examined the data obtained from 323 consecutive patients with advanced renal dysfunction (eGFR <30 ml/min/1.73 m²) who underwent PCI at 5 hospitals. CIN was defined as a ≥25% increase in baseline serum creatinine levels and/or a ≥0.5 mg/dl increase in absolute serum creatinine levels within 72 hours after PCI. Incidence of all-cause death and the initiation of permanent dialysis were examined during follow-up. The prevalence of emergency/urgent PCI was 53.3%. Intravascular ultrasound was used in 266 patients (82.4%), and the volume of contrast used was 71.7 ± 57.2 ml. CIN was observed in 31 patients (9.7%). The median follow-up duration was 656 days (interquartile range 257-1143 days). The cumulative rates of all-cause death or the initiation of permanent dialysis, all-cause death, and the initiation of permanent dialysis were 38.1%, 25.9%, and 18.2%, respectively, at 2 years. A comparison between patients with and without CIN showed no significant intergroup differences in the occurrence of the aforementioned events. In conclusion, the incidence of CIN was not high in Japanese patients with advanced renal dysfunction in routine clinical practice. Whereas, the long-term prognosis following PCI is observed to be poor in this studied population, and CIN did not show a significant prognostic influence.

Minimizing radiographic contrast administration during coronary angiography using a novel contrast reduction system: A multicenter observational study of the DyeVert™ plus contrast reduction system

OBJECTIVE

To evaluate contrast media (CM) volume (CMV) saved using the DyeVert™ Plus Contrast Reduction System (DyeVert Plus System, Osprey Medical) in patients undergoing diagnostic coronary angiogram (CAG) and/or percutaneous coronary interventional (PCI) procedures performed with manual injections.

BACKGROUND

Current guidelines advocate for monitoring and minimization of the total volume of CM in chronic kidney disease (CKD) patients undergoing invasive cardiac procedures. The DyeVert Plus System is an FDA cleared device designed to reduce CMV delivered during angiography and permit real-time CMV monitoring.

METHODS

We performed a multicenter, single-arm, observational study. Eligible subjects were ≥ 18 years old with baseline estimated glomerular filtration rate (eGFR) 20-60 mL/min/1.73 m² . The primary endpoint was % CMV saved over the total procedure. A secondary objective was to evaluate adverse events (AEs) related to DyeVert Plus System or to CM use.

RESULTS

A total of 114 subjects were enrolled at eight centers. Mean age was 72 ± 9 years, 72% were male, and mean body mass index was 29 ± 5. Baseline eGFR was 43 ± 11 mL/min/1.73 m² . CAG-only was performed in 65% of cases. One hundred and five subjects were evaluable for the primary endpoint. Mean CMV attempted was 112 ± 85 mL (range 22-681) and mean CMV delivered was 67 ± 51 mL (range 12-403), resulting in an overall CMV savings of 40.1 ± 8.8% (95% CI 38.4, 41.8; P < 0.0001) per procedure. Image quality was maintained in all but one case where the system was turned off for one injection. No DyeVert Plus System-related AEs were reported. Acute kidney injury (AKI; defined as serum creatinine rise of >0.3 mg/dL from baseline) was reported in 11 cases with seven occurring in subjects with baseline eGFR < 30 and three AKI events were attributed to CM. AKI rates increased as CMV/eGFR ratios increased.

CONCLUSIONS

These data suggest DyeVert Plus System use in CKD patients undergoing CAG and/or PCI results in clinically meaningful CMV savings while maintaining image quality.

Maximum allowable contrast dose and prevention of acute kidney injury following cardiovascular procedures

PURPOSE OF REVIEW

Contrast-induced acute kidney injury (CI-AKI) is a serious complication. Although nonmodifiable and modifiable risk factors have been thoroughly characterized, the utility of the maximal allowable contrast dose (MACD) has not received adequate attention. The focus of this review is to provide a critical appraisal of this modifiable risk factor.

RECENT FINDINGS

Several retrospective and prospective cohort studies have demonstrated that the incidence of CI-AKI among patients receiving contrast media in volumes exceeding the MACD is consistently higher compared with those who do not exceed the MACD (an average of 24 vs. 6%). Furthermore, the MACD is independent predictor of CI-AKI and other adverse events. A two-step algorithm incorporating the determination of the MACD and the contrast volume to eGFR ratio prior to a planned cardiovascular procedure is a sound approach to minimize contrast volume and prevent CI-AKI.

SUMMARY

Prevention of CI-AKI must remain a clinical priority. Intraprocedural preventive measures should include a priori calculation of the MACD and contrast volume to eGFR ratio to limit contrast volume. Other measures may include the adoption of the transradial approach, the use of automated contrast injectors and small catheters to limit contrast volume, the use of low-osmolar contrast agents, and if necessary the use of staged procedures. We call for the system-wide implementation of evidence-based care bundles to prevent CI-AKI.

Contrast Volume to Cystatin C-Based Glomerular Filtration Ratio Predicts the Risk of Contrast-Induced Nephropathy After Cardiac Catheterization

Cystatin C is considered to be a better alternative to creatinine for estimating glomerular filtration rate (GFR). The aim of this study was to investigate whether a contrast volume to estimated GFR based on cystatin C (V/eGFRcys) is a better predictor of contrast-induced nephropathy (CIN). We enrolled 1195 consecutive patients undergoing elective cardiac catheterization. Receiver–operating characteristic (ROC) curves were used to identify the optimal cutoff value of V/eGFRcys for detecting CIN. Multivariate regression models were used to evaluate whether V/eGFRcys is an independent risk factor for CIN. A total of 19 (1.6%) patients developed CIN. There was a significant association between a higher V/eGFRcys ratio and CIN risk ( P = .008). A ROC curve analysis indicated that a V/eGFRcys ratio of 2.29 was a fair discriminator for CIN. After adjusting for other known CIN risk factors, V/eGFRcys ratios >2.29 remained significantly associated with CIN (odds ratio = 2.93, 95% confidence interval: 1.02-8.44, P = .047). In conclusion, a V/eGFRcys >2.29 was a significant and independent predictor of CIN after cardiac catheterization.

Safe contrast volumes for preventing contrast-induced nephropathy in elderly patients with relatively normal renal function during percutaneous coronary intervention

The aim of this study was to evaluate contrast media volume to creatinine clearance (V/CrCl) ratio for predicting contrast-induced nephropathy (CIN) and to determine a safe V/CrCl cut off value to avoid CIN in elderly patients with relatively normal renal function during percutaneous coronary intervention (PCI). We prospectively enrolled 1020 consecutive elderly patients (age ≥65 years) with relative normal renal function (baseline serum creatinine <1.5 mg/dL) undergoing PCI. Receiver operating characteristic (ROC) curves were used to identify the optimal cut off value of V/CrCl for detecting CIN. The predictive value of V/CrCl for CIN was assessed with a multivariate logistic regression. Thirty-nine patients (3.8%) developed CIN. There was a significant association between a higher V/CrCl ratio and CIN risk (P < 0.001). ROC curve analysis indicated that a V/CrCl ratio of 2.74 was a fair discriminator for CIN (C statistic = 0.68). After adjusting for other known CIN risk factors, V/CrCl ratios >2.74 remained significantly associated with CIN (odds ratio = 3.21, 95% confidence interval [CI] 1.45-7.09, P = 0.004) and worse long-term mortality (hazard ratio = 1.96, 95% CI 1.14-3.38, P = 0.016). A V/CrCl ratio >2.74 was a significant independent predictor of CIN and was independently associated with long-term mortality in elderly patients with relatively normal renal function.