The changing definition of contrast-induced nephropathy and its clinical implications: insights from the Blue Cross Blue Shield of Michigan Cardiovascular Consortium (BMC2)

Anemia and periprocedural complications determine contrast-associated acute kidney injury after recanalization of chronic coronary occlusions in chronic kidney disease

BACKGROUND

Contrast-associated acute kidney injury (CA-AKI) is a potential risk associated with the percutaneous coronary interventions (PCI) for chronic total coronary occlusions (CTO) particularly with pre-existing chronic kidney disease (CKD). The determinants of CA-AKI in patients with pre-existing CKD in an era of advanced strategies of CTO recanalization techniques need to be considered for a risk evaluation of the procedure.

METHODS

A consecutive cohort of 2504 recanalization procedures for a CTO between 2013 and 2022 was analyzed. Of these, 514 (20.5%) were done in patients with CKD (estimated glomerular filtration rate < 60 ml/min based on the most recently used CKD Epidemiology Collaboration equation).

RESULTS

The rate of patients classified to have CKD would be lower with 14.2% using the Cockcroft-Gault equation, and 18.1% using the modified Modification of Diet in Renal Disease equation. The technical success was high with 94.9% and 96.8% (p = 0.04) between patients with and without CKD. The incidence of CA-AKI was 9.9% versus 4.3% (p < 0.001). The major determinants of CA-AKI in patients with CKD were the presence of diabetes and a reduced ejection fraction, as well as periprocedural blood loss, whereas a higher baseline hemoglobin and the use of the radial approach prevented CA-AKI.

CONCLUSIONS

In patients with CKD CTO PCI could be performed successfully at a higher cost of CA-AKI. Correcting preprocedural anemia and avoiding intraprocedural blood loss may reduce the incidence of CA-AKI.

The acute impact of baseline renal function and contrast medium volume/estimated glomerular filtration rate ratio on reduced renal function following endovascular abdominal aortic aneurysm repair

OBJECTIVE

The aim of this study was to determine the acute impact of baseline serum creatinine, estimated glomerular filtration rate (eGFR), and contrast medium volume (CMV) on the incidence of reduced renal function (RRF) after endovascular abdominal aortic aneurysm repair (EVAR). We aimed to determine if the CMV/eGFR ratio was a predictor of RRF.

METHODS

This study is a retrospective review of EVAR patients in the Society for Vascular Surgery/Vascular Quality Initiative (SVS/VQI) from January 2015 to August 2020. Reduced renal function was defined as > 0.3 mg/dl (26.5 μmol/L), 50% increase from baseline, and temporary or permanent dialysis. Receiver operator characteristic (ROC) curve analyses were conducted for serum creatinine, eGFR, contrast volume, fluid volume, and CMV/eGFR ratio. Two data sets (training and test) were developed followed by multivariate analyses.

RESULTS

SVS/VQI data for EVAR contained 38,701 records, of which 30,539 were divided into training (n = 18,283; 60%) and test (n = 12,256; 40%) data sets. RRF rate for the training set was 3.6% (n = 667) and 3.4% (n = 420) for the test data. RRF patients included more females (29.4 vs 19.0%, p < 0.001), were older in age (75.6 + 8.4 vs 73.3 + 8.7 years), had more congestive heart failure (22.3 vs 12.2%, p < 0.001), and more COPD (42.0 vs 34.2%, p < 0.001). An ROC analysis revealed that eGRF, creatinine, contrast, intravenous fluid, and contrast medium volume (CMV)/eGFR ratio were all significantly (p < 0.05) correlated with RRF. The eGFR and CMV/eGFR ratio had the largest area under the curve, (0.26) and (0.65), respectively, while fluid had the lowest (0.54). Negative predictive values were 93.7 (CMV/eGFR), 93.9 (creatinine), 94.2 (eGFR), 92.8 (contrast), and 92.6 (intravenous fluid). Multivariate analysis of the training data set resulted in the CMV/eGFR ratio as an independent predictor of RRF (odds ratio, OR: 1.9 with 95% CI: 1.6, 2.2, p < 0.015). For the test data, the CMV/eGFR ratio was an independent predictor of RRF (OR: 1.8, CI: 1.4 to 2.2, p < 0.001) as well as several other variables.

CONCLUSION

RRF after EVAR is a dreaded and potentially devastating complication. Baseline serum creatinine, eGFR, contrast medium volume, and the ratio (CMV/eGFR) were all significantly associated with RRF. The optimal cut-off value for the CMV/eGFR ratio, ≤ 2, provides an easy-to-use equation to provide a suggested contrast target based on initial renal function with caution applied for high-risk patients.

Incidence, predictors and clinical implications of new renal impairment following percutaneous coronary intervention

Background

Renal impairment post-percutaneous coronary intervention (post-PCI) is a well-described adverse effect following the administration of contrast media. Within a large cohort of registry patients, we aimed to explore the incidence, predictors and clinical outcomes of renal impairment post-PCI.

Methods

The Victorian Cardiac Outcomes Registry is an Australian state-based clinical quality registry focusing on collecting data from all PCI capable centres. Data from 36 970 consecutive PCI cases performed between 2014 and 2018 were analysed. Patients were separated into three groups based on post-procedure creatinine levels (new renal impairment (NRI), defined as an absolute rise in serum creatinine>44.2 µmol/L or>25% of baseline creatinine; new renal impairment requiring dialysis (NDR), defined as worsening renal failure that necessitated a new requirement for renal dialysis; no NRI). Multivariate logistic regression analysis was performed to investigate the impact of NRI and NDR on clinical outcomes.

Results

3.1% (n=1134) of patients developed NRI, with an additional 0.6% (n=225) requiring dialysis. 96.3% (n=35 611) of patients did not develop NRI. Those who developed renal impairment were more comorbid, with higher rates of diabetes (22% vs 38% vs 38%, p<0.001), peripheral vascular disease (3.4% vs 8.2% vs 11%, p<0.001), chronic kidney disease (19% vs 49.7% vs 54.2%) and severe left ventricular dysfunction (5% vs 22% vs 40%, p<0.001). Multivariable analysis found that when compared with the no NRI group, those in the combined NRI/NDR group were at a greater risk of 30-day mortality (OR 4.77; 95% CI 3.89 to 5.86, p<0.001) and 30-day major adverse cardiac events (OR 3.72; 95% CI 3.15 to 4.39, p<0.001).

Conclusions

NRI post-PCI remains a common occurrence, especially among comorbid patients, and is associated with a significantly increased morbidity and mortality risk.

Trends and outcomes of percutaneous coronary intervention during the COVID-19 pandemic in Michigan

Background

The COVID-19 pandemic has severely impacted healthcare delivery and patient outcomes globally.

Aims

We aimed to evaluate the influence of the COVID-19 pandemic on the temporal trends and outcomes of patients undergoing percutaneous coronary intervention (PCI) in Michigan.

Methods

We compared all patients undergoing PCI in the BMC2 Registry between March and December 2020 (“pandemic cohort”) with those undergoing PCI between March and December 2019 (“pre-pandemic cohort”). A risk-adjusted analysis of in-hospital outcomes was performed between the pre-pandemic and pandemic cohort. A subgroup analysis was performed comparing COVID-19 positive vs. negative patients during the pandemic.

Results

There was a 15.2% reduction in overall PCI volume from the pre-pandemic (n = 25,737) to the pandemic cohort (n = 21,822), which was more pronounced for stable angina and non-ST-elevation acute coronary syndromes (ACS) presentations, and between February and May 2020. Patients in the two cohorts had similar clinical and procedural characteristics. Monthly mortality rates for primary PCI were generally higher in the pandemic period. There were no significant system delays in care between the cohorts. Risk-adjusted mortality was higher in the pandemic cohort (aOR 1.26, 95% CI 1.07–1.47, p = 0.005), a finding that was only partially explained by worse outcomes in COVID-19 patients and was more pronounced in subjects with ACS. During the pandemic, COVID-19 positive patients suffered higher risk-adjusted mortality (aOR 5.69, 95% CI 2.54–12.74, p<0.001) compared with COVID negative patients.

Conclusions

During the COVID-19 pandemic, we observed a reduction in PCI volumes and higher risk-adjusted mortality. COVID-19 positive patients experienced significantly worse outcomes.

Elevated Serum Uric Acid/Albumin Ratio as a Predictor of Post-Contrast Acute Kidney Injury After Percutaneous Coronary Intervention in Patients with ST-Segment Elevation Myocardial Infarction

Background

The serum uric acid/albumin ratio (sUAR), a novel inflammatory marker, effectively predicts acute kidney injury (AKI) and cardiovascular outcomes. However, whether the sUAR predicts post-contrast acute kidney injury (PC-AKI) in patients with ST-segment elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI) remains uncertain. In this study, we evaluated the association between the sUAR and PC-AKI in patients with STEMI undergoing PCI.

Methods

We consecutively recruited patients with STEMI who underwent PCI and stratified them into three groups according to the terciles of the sUAR. The primary outcome was the incidence of PC-AKI. The association between the sUAR and PC-AKI was assessed by multivariate logistic regression analysis.

Results

A total of 2861 patients with STEMI were included in this study. The incidence of PC-AKI increased stepwise with increasing sUAR tercile (2.6% vs 4.0% vs 11.6%, p < 0.001), and the incidence of in-hospital major adverse clinical events (MACEs) was highest among patients in the Q3 group. Multivariate logistic regression analysis revealed that the sUAR was also an independent predictor of PC-AKI (continuous sUAR, per 1-unit increase, odds ratio [OR] [95% confidence interval (CI)]: 1.06 [1.02–1.10], p = 0.005; tercile of sUAR, OR [95% CI] for Q2 and Q3: 1.18 [0.69–2.01] and 1.85 [1.12–3.06], respectively, with Q1 as a reference) but not in-hospital MACEs. In the receiver operating characteristic (ROC) analysis, the area under the curve (AUC) of the sUAR for predicting PC-AKI was 0.708 (95% CI: 0.666–0.751), and ROC analysis also showed that the sUAR was superior to uric acid and albumin alone in predicting PC-AKI.

Conclusion

Increasing sUAR was significantly associated with a higher risk of PC-AKI but not in-hospital MACEs in patients with STEMI who underwent PCI, suggesting that sUAR had a predictive value for PC-AKI after PCI in patients with STEMI. Further studies are required to confirm this finding.

Contrast-Associated Acute Kidney Injury

Contrast-associated acute kidney injury (CA-AKI) is an impairment of renal function, which occurs within days of intravascular administration of iodinated contrast media. Taking into account that minimally invasive cardiac interventions are becoming increasingly popular, compared to traditional surgery, given their impact on prognosis and costs, CA-AKI remains a subject of increasing interest for patients and physicians. This review summarizes the epidemiology and risk stratification, diagnostic criteria, pathophysiology and clinical implications of CA-AKI, providing evidence for the most studied preventive strategies.

The Pathophysiology and the Management of Radiocontrast-Induced Nephropathy

Contrast-induced nephropathy (CIN) is an impairment of renal function that occurs after the administration of an iodinated contrast medium (CM). Kidney dysfunction in CIN is considered transient and reversible in most cases. However, it is the third most common cause of hospital-acquired acute kidney injury and is associated with increased morbidity and mortality, especially in high-risk patients. Diagnostic and interventional procedures that require intravascular CM are being used with increasing frequency, especially among the elderly, who can be particularly susceptible to CIN due to multiple comorbidities. Therefore, identifying the exact mechanisms of CIN and its associated risk factors is crucial not only to provide optimal preventive management for at-risk patients, but also to increase the feasibility of diagnostic and interventional procedure that use CM. CM induces kidney injury by impairing renal hemodynamics and increasing the generation of reactive oxygen species, in addition to direct cytotoxicity. Periprocedural hydration is the most widely accepted preventive strategy to date. Here, we review the latest research results on the pathophysiology and management of CIN.

Strategies for Renal Protection in Cardiovascular Interventions

Contrast-associated acute kidney injury (CA-AKI), a potential complication of cardiovascular interventions that require radiocontrast administration, is associated with increased morbidity, mortality, and length of hospital admission. CA-AKI is particularly prevalent among patients with chronic kidney disease and comorbidities such as advanced age and diabetes. This review briefly discusses the evidence-based strategies to minimize CA-AKI. In addition, technical details of procedures to minimize the contrast volume, i.e., ultra-low contrast angiography and zero contrast percutaneous intervention, along with several illustrative cases are presented.

Coronary artery disease is highly prevalent in chronic kidney disease (CKD) and is a risk factor for contrast-associated acute kidney injury (CA-AKI), a complication of cardiovascular procedures that require contrast administration (e.g., coronary angiography, percutaneous coronary intervention [PCI]). CA-AKI has a major impact on morbidity, mortality, and healthcare resource utilization. The incidence of CA-AKI is particularly high in patients with pre-existing CKD, advanced age and comorbidities that increase the likelihood of CKD. The focus of the present review is to provide a brief overview on the assessment of the risk for and prevention of CA-AKI in patients undergoing angiography and PCI, including recognition of the important patient- and procedure-related factors that may contribute to CA-AKI. Preventive and treatment strategies, the mainstay of which is volume repletion by normal saline, are briefly discussed. The main focus of the review is placed on technical details of contrast minimization techniques, including ultra-low contrast angiography and zero-contrast PCI. Operator competence in such techniques is important to ensure that procedural challenges in patients with CKD, like vessel calcification, multivessel disease and complex anatomical subsets, are effectively addressed by PCI while minimizing the risk of CA-AKI.

A Comparison Between Two Definitions of Contrast-Associated Acute Kidney Injury for Long-Term Mortality in Elderly and Non-elderly Patients After Elective Percutaneous Coronary Intervention

Background: Contrast-associated acute kidney injury (CA-AKI) is responsible for a substantial proportion of the observed mortality that occurs after percutaneous coronary intervention (PCI), particularly in elderly patients. However, there has been significant and debate over whether the optimal definition of CA-AKI persists over prolonged periods due to variations in the prevalence and effects on prognosis. In this study, we aimed to identify whether different definitions of CA-AKI exert differential impacts on long-term mortality when compared between elderly and non-elderly patients receiving elective PCI. Methods: We prospectively investigated 5,587 consenting patients undergoing elective PCI between January 2012 and December 2018. We considered two classical definitions of CA-AKI from the European Society of Urogenital Radiology (ESUR) and the Acute Kidney Injury Network (AKIN). Multivariable Cox regression analysis was used to investigate the association between CA-AKI and long-term mortality. We also performed interaction and stratified analyses according to age (≤75 or >75 years). Results: The incidence of CA-AKI according to the ESUR and AKIN definitions was 18.7 and 6.1%, respectively. After a median follow-up of 2.1 years, multivariable Cox regression analysis indicated that CA-AKI according to the AKIN definition was a risk factor for long-term mortality in the overall population [hazard ratio (HR) = 2.20; 95% confidential interval (CI): 1.51-3.22; p < 0.001]; however, this was not the case for the ESUR definition (HR = 1.27; 95% CI: 0.92-1.76; p = 0.153). Further interaction analysis identified a significant interaction between age and the ESUR definition (p = 0.040). Stratified analyses also found an association between the ESUR definition and long-term mortality in patients >75 years of age (p = 0.011), but not in patients ≤75 years of age (p = 0.657). Conclusion: As a stringent definition of CA-AKI, the AKIN definition was significantly associated with long-term mortality in both non-elderly and elderly patients. However, in elderly patients, the more lenient definition provided by the ESUR was also significantly correlated with long-term mortality, which could sensitively identify high-risk elderly patients and may provide a better alternative.

Acute kidney injury in patients with acute coronary syndrome undergoing invasive management treated with bivalirudin vs. unfractionated heparin: insights from the MATRIX trial

AIMS

Acute kidney injury (AKI) is a critical complication among patients with acute coronary syndrome (ACS) undergoing invasive management. The value of adjunctive antithrombotic strategies, such as bivalirudin or unfractionated heparin (UFH) on the risk of AKI is unclear.

METHODS AND RESULTS

Among 7213 patients enrolled in the MATRIX-Antithrombin and Treatment Duration study, 128 subjects were excluded due to incomplete information on serum creatinine (sCr) or end-stage renal disease on dialysis treatment. The primary endpoint was AKI defined as an absolute (>0.5 mg/dL) or a relative (>25%) increase in sCr. AKI occurred in 601 patients (16.9%) treated with bivalirudin and 616 patients (17.4%) treated with UFH [odds ratio (OR): 0.97; 95% confidence interval (CI): 0.85-1.09; P = 0.58]. A >25% sCr increase was observed in 597 patients (16.8%) with bivalirudin and 616 patients (17.4%) with UFH (OR: 0.96; 95% CI: 0.85-1.08; P = 0.50), whereas a >0.5 mg/dL absolute sCr increase occurred in 176 patients (5.0%) with bivalirudin vs. 189 patients (5.4%) with UFH (OR: 0.92; 95% CI: 0.75-1.14; P = 0.46). By implementing the Kidney Disease Improving Global Outcomes (KDIGO) criteria, the risk of AKI was not significantly different between bivalirudin and UFH groups (OR: 0.88; 95% CI: 0.72-1.07; P = 0.21). Subgroup analyses of the primary endpoint suggested a benefit with bivalirudin in patients randomized to femoral access.

CONCLUSION

Among ACS patients undergoing invasive management, the risk of AKI was not significantly lower with bivalirudin compared with UFH.

TRIAL REGISTRATION

clinicaltrials.gov NCT01433627.

Marijuana Use and In-Hospital Outcomes After Percutaneous Coronary Intervention in Michigan, United States

OBJECTIVES

The aim of this study was to evaluate the association between reported marijuana use and post-percutaneous coronary intervention (PCI) in-hospital outcomes.

BACKGROUND

Marijuana use is increasing as more states in the United States legalize its use for recreational and medicinal purposes. Little is known about the frequency of use and relative safety of marijuana among patients presenting for PCI.

METHODS

The authors analyzed Blue Cross Blue Shield of Michigan Cardiovascular Consortium PCI registry data between January 1, 2013, and September 30, 2016. One-to-one propensity matching and multivariable logistic regression were used to adjust for differences between patients with or without reported marijuana use, and rates of post-PCI complications were compared.

RESULTS

Among 113,477 patients, 3,970 reported marijuana use. Compared with those without reported marijuana use, patients with reported marijuana use were likely to be younger (53.9 years vs 65.8 years), to use tobacco (73.0% vs 26.8%), to present with ST-segment elevation myocardial infarction (27.3% vs 15.9%), and to have fewer cardiovascular comorbidities. After matching, compared with patients without reported marijuana use, those with reported marijuana use experienced significantly higher risks for bleeding (adjusted odds ratio [aOR]: 1.54; 95% confidence interval [CI]: 1.20-1.97; P < 0.001) and cerebrovascular accident (aOR: 11.01; 95% CI: 1.32-91.67; P = 0.026) and a lower risk for acute kidney injury (aOR: 0.61; 95% CI: 0.42-0.87; P = 0.007). There were no significant differences in risks for transfusion and death.

CONCLUSIONS

A modest fraction of patients undergoing PCI used marijuana. Reported marijuana use was associated with higher risks for cerebrovascular accident and bleeding and a lower risk for acute kidney injury after PCI. Clinicians and patients should be aware of the higher risk for post-PCI complications in these patients.

Contrast-induced nephropathy in non-cardiac vascular procedures, a narrative review: Part 1

Contrast-induced nephropathy (CIN) is an important complication of iodinated contrast medium (CM) administration, which is associated with both short- and long-term adverse outcomes (e.g., cardiorenal events, longer hospital stay, and mortality). CIN has been mainly studied in relation to cardiac procedures, but it can also occur following non-cardiac vascular interventions. This is Part 1 of a narrative review summarizing the available literature on CIN after non-cardiac vascular diagnostic or therapeutic procedures for aortic aneurysm and carotid stenosis. We discuss the definition, pathophysiology, incidence, risk factors, biomarkers, and consequences of CIN in these settings, as well as preventive strategies and alternatives to limit iodinated CM use. Physicians and vascular surgeons should be aware of CM-related adverse events and the potential strategies to avoid them. Clearly, more research in this important field is required.

A prospective study on the incidence of contrast-associated acute kidney injury after recanalization of chronic total coronary occlusions with contemporary interventional techniques

BACKGROUND

Contrast-associated acute kidney injury (CA-AKI) is a potential risk associated with the percutaneous coronary interventions (PCI) for chronic total coronary occlusions (CTO). This study should evaluate the incidence of CA-AKI in an era of advanced strategies of recanalization techniques and identify modifiable determinants.

METHODS

We analysed 1924 consecutive CTO procedures in 1815 patients between 2012 and 2019. All patients were carefully monitored at least up to 48 h after a CTO procedure for changes in renal function.

RESULTS

The incidence of CA-AKI was 5.6%, but there was no relation to the technical approach such as frequency of the retrograde technique, intravascular ultrasound or radial access. Procedures with CA-AKI had longer fluoroscopy times (37.6 vs 46.1 min; p = 0.005). The major determinants of CA-AKI were age, presence of diabetes and reduced ejection fraction, as well as chronic kidney disease stage ≥2, serum haemoglobin, and fluoroscopy time. Contrast volume or contrast volume/GFR ratio were not independent determinants of CA-AKI. Periprocedural perforations were more frequent in CA-AKI patients (11.3 vs 2.3%; p < 0.001), and in-hospital mortality was higher (2.8 vs 0.4%; p < 0.001).

CONCLUSIONS

CA-AKI was associated with the risk of in-hospital adverse events. Established patient-related risk factors for CA-AKI (age, diabetes, preexisting chronic kidney disease, low ejection fraction) were confirmed in this study. In addition, the length of the procedure, coronary perforations and low preprocedural serum haemoglobin were risk factors that might be preventable in patients at high risk for CA-AKI.

Acute kidney injury following endovascular intervention for peripheral artery disease

BACKGROUND

The incidence of, and risk factors for, acute kidney injury (AKI) after endovascular intervention for peripheral artery disease (PAD) remain unknown. The aim of this study was to assess the proportion of patients who develop AKI and explore the risk factors.

METHODS

Prospectively collected data on patients undergoing femoropopliteal endovascular intervention for symptomatic PAD across three vascular centres were analysed. The proportion of patients developing AKI (according to the Kidney Disease Improving Global Outcomes definition) within 48 h, and the proportion developing the composite Major Adverse Kidney Events (MAKE) endpoints (death, dialysis, drop in estimated glomerular filtration rate at least 25 per cent) at 30 days (MAKE30) and remains 90 days (MAKE90) were calculated. Multivariable regression analysis was used to assess predictors of AKI, and the association between AKI and death.

RESULTS

Some 2041 patients were included in the analysis. AKI developed in 239 patients (11.7 per cent), with 47 (2.3 per cent) requiring dialysis within 30 days, and 18 (0.9 per cent) requiring ongoing dialysis. The MAKE30 and MAKE90 composite endpoints were reached in 358 (17.5 per cent) and 449 (22.0 per cent) patients respectively. Risk factors for AKI were age, sex, congestive heart failure, chronic limb-threatening ischaemia, emergency procedure, and pre-existing chronic kidney disease. AKI, dementia, congestive heart failure, and major amputation were risk factors for medium-term mortality.

CONCLUSION

AKI is a common complication after intervention for PAD and is associated with medium-term mortality.

Trends and outcomes of non-primary PCI at sites without cardiac surgery on-site: The early Michigan experience

Introduction

Non-primary percutaneous coronary intervention (non-PPCI) recently received certificate of need approval in the state of Michigan at sites without cardiac surgery on-site (cSoS). This requires quality oversight through participation in the BMC2 registry. While previous studies have indicated the safety of this practice, real-world comprehensive outcomes, case volume changes, economic impacts, and readmission rates at diverse healthcare centers with and without cSoS remain poorly understood.

Methods

Consecutive patients undergoing non-PPCI at 47 hospitals (33 cSoS and 14 non-cSoS) in Michigan from April 2016 to March 2018 were included. Using propensity-matching, patients were analyzed to assess outcomes and trends in non-PPCI performance at sites with and without cSOS.

Results

Of 61,864 PCI’s performed, 50,817 were non-PPCI, with 46,096 (90.7%) performed at sites with cSoS and 4,721 (9.3%) at sites without cSoS. From this cohort, 4,643 propensity-matched patients were analyzed. Rates of major adverse cardiac events (2.6% vs. 2.8%; p = 0.443), in-hospital mortality (0.6% vs. 0.5%; p = 0.465), and several secondary clinical and quality outcomes showed no clinically significant differences. Among a small subset with available post-discharge data, there were no differences in 90-day readmission rates, standardized episode costs, or post-discharge mortality. Overall PCI volume remained stable, with a near three-fold rise in non-PPCI at sites without cSoS.

Conclusions

Non-PPCI at centers without cardiac SoS was associated with similar comprehensive outcomes, quality of care, 90-day episode costs, and post-discharge mortality compared with surgical sites. Mandatory quality oversight serves to maintain appropriate equivalent outcomes and may be considered for other programs, including the performance of non-PPCI at ambulatory surgical centers in the near future.

Contrast-Induced Acute Kidney Injury-Definitions, Epidemiology, and Implications

Contrast-induced acute kidney injury (CI-AKI) is the acute onset of renal injury following exposure to iodinated contrast media. Several definitions have been used, which complicates the estimation of the epidemiological relevance of this condition and comparisons in outcome research. The incidence of CI-AKI increases as a function of patient and procedure complexity in coronary, endovascular, and structural interventions. CI-AKI is associated with a high burden of short- and long-term adverse events, and leads to increased healthcare costs. This review will provide an overview of the definitions, epidemiology, and implications of CI-AKI in patients undergoing coronary, endovascular, and structural catheter-based procedures.

Exploring Triaging and Short-Term Outcomes of Early Invasive Strategy in Non-ST Segment Elevation Acute Coronary Syndrome: A Report from Japanese Multicenter Registry

This observational study aimed to examine the extent of early invasive strategy (EIS) utilization in patients with non-ST elevation acute coronary syndrome (NSTE-ACS) according to the National Cardiovascular Data Registry (NCDR) CathPCI risk score, and its association with clinical outcomes. Using a prospective multicenter Japanese registry, 2968 patients with NSTE-ACS undergoing percutaneous coronary intervention within 72 hours of hospital arrival were analyzed. Multivariable logistic regression analyses were performed to determine predictors of EIS utilization. Additionally, adverse outcomes were compared between patients treated with and without EIS. Overall, 82.1% of the cohort (n = 2436) were treated with EIS, and the median NCDR CathPCI risk score was 22 (interquartile range: 14-32) with an expected 0.3-0.6% in-hospital mortality. Advanced age, peripheral artery disease, chronic kidney disease or patients without elevation of cardiac biomarkers were less likely to be treated with EIS. EIS utilization was not associated with a risk of in-hospital mortality; yet, it was associated with an increased risk of acute kidney injury (AKI) (adjusted odds ratio: 1.42; 95% confidence interval: 1.02-2.01) regardless of patients' in-hospital mortality risk. Broader use of EIS utilization comes at the cost of increased AKI development risk; thus, the pre-procedural risk-benefit profile of EIS should be reassessed appropriately in patients with lower mortality risk.

Random forest for prediction of contrast-induced nephropathy following coronary angiography

The majority of prediction models for contrast-induced nephropathy (CIN) have moderate performance. Therefore, we aimed to develop a better pre-procedural prediction tool for CIN following contemporary percutaneous coronary intervention (PCI) or coronary angiography (CAG). A total of 3469 patients undergoing PCI/CAG between January 2010 and December 2013 were randomly divided into a training (n = 2428, 70%) and validation data-sets (n = 1041, 30%). Random forest full models were developed using 40 pre-procedural variables, of which 13 variables were selected for a reduced CIN model. CIN developed in 78 (3.21%) and 37 of patients (3.54%) in the training and validation datasets, respectively. In the validation dataset, the full and reduced models demonstrated improved discrimination over classic Mehran, ACEF CIN risk scores (AUC 0.842 and 0.825 over 0.762 and 0.701, respectively, all P < 0.05) and common estimated glomerular filtration rate. Compared to that for the Mehran risk score model, the full and reduced models had significantly improved fit based on the net reclassification improvement (all P < 0.001) and integrated discrimination improvement (P = 0.001, 0.028, respectively). Using the above models, 2462 (66.7%), 661, and 346 patients were categorized into low (< 1%), moderate (1% to 7%), and high (> 7%) risk groups, respectively. Our pre-procedural CIN risk prediction algorithm (http://cincalc.com) demonstrated good discriminative ability and was well calibrated when validated. Two-thirds of the patients were at low CIN risk, probably needing less peri-procedural preventive strategy; however, the discriminative ability of CIN risk requires further external validation. TRIAL REGISTRATION: ClinicalTrials.gov NCT01400295.

Development and Validation of a Model for Predicting the Risk of Acute Kidney Injury Associated With Contrast Volume Levels During Percutaneous Coronary Intervention

Importance

Determining the association of contrast volume during percutaneous coronary intervention (PCI) with the risk of acute kidney injury (AKI) is important for optimizing PCI safety.

Objective

To quantify how the risk of AKI is associated with contrast volume, accounting for the possibility of nonlinearity and heterogeneity among different baseline risks.

Design, Setting, and Participants

This prognostic study used data from the American College of Cardiology National Cardiovascular Data Registry CathPCI Registry for 1694 US hospitals. Derivation analysis included 2 076 694 individuals who underwent PCI from July 1, 2011, to June 30, 2015. Validation analysis included 961 863 individuals who underwent PCI from July 1, 2015, to March 31, 2017. Data analysis took place from July 2018 to May 2019.

Exposure

Contrast volume during PCI.

Main Outcomes and Measures

Acute kidney injury was defined using 3 thresholds for preprocedure to postprocedure creatinine level increase (ie, ≥0.3 mg/dL, ≥0.5 mg/dL, and ≥1.0 mg/dL). A model quantifying the association of contrast volume with AKI was developed, and the existence of nonlinearity and heterogeneity were examined by likelihood ratio tests. The model was derived in the training set (a random 50% of the derivation cohort), and performance was evaluated in the test set (the remaining 50% of the derivation cohort) and an independent validation set by area under the receiver operating characteristic curve (AUC) and calibration slope of observed vs predicted risks.

Results

The 2 076 694 patients in the derivation set had a mean (SD) age of 65.1 (12.1) years, and 662 525 (31.9%) were women; 133 306 (6.4%) had creatinine level increases of at least 0.3 mg/dL, 66 626 (3.2%) had creatinine level increases of at least 0.5 mg/dL, and 28 378 (1.4%) had creatinine level increases of at least 1.0 mg/dL. In the validation set of 961 843 patients (mean [SD] age, 65.7 [12.1] years; 305 577 [31.8%] women), these rates were 62 913 (6.5%), 34 229 (3.6%), and 15 555 (1.6%), respectively. The association of contrast volume and AKI risk was nonlinear (χ226 = 1436.2; P < .001) and varied by preprocedural risk (χ220 = 105.6; P < .001). In the test set, the model yielded an AUC of 0.777 (95% CI, 0.775-0.779) for predicting risk of a creatinine level increase of at least 0.3 mg/dL, 0.839 (95% CI, 0.837-0.841) for predicting risk of a creatinine level increase of at least 0.5 mg/dL, and 0.870 (95% CI, 0.867-0.873) for predicting risk of a creatinine level increase of at least 1.0 mg/dL; it achieved a calibration slope of 0.998 (95% CI, 0.989-1.007), 0.999 (95% CI, 0.989-1.008), and 0.986 (95% CI, 0.973-0.998), respectively, for the AKI severity levels. The model had similar performance in the validation set (creatinine level increase of ≥0.3 mg/dL: AUC, 0.794; 95% CI, 0.792-0.795; calibration slope, 1.039; 95% CI, 1.030-1.047; creatinine level increase of ≥0.5 mg/dL: AUC, 0.845; 95% CI, 0.843-0.848; calibration slope, 1.063; 95% CI, 1.054-1.074; creatinine level increase of ≥1.0 mg/dL: AUC, 0.872; 95% CI, 0.869-0.875; calibration slope, 1.103; 95% CI, 1.089-1.117).

Conclusions and Relevance

The association of contrast volume with AKI risk is complex, varies by baseline risk, and can be predicted by a model. Future research to evaluate the effect of the model on AKI is needed.

A novel simple experimental model for low-osmolar contrast-induced acute kidney injury using different definitions based on the levels of serum creatinine and cystatin C

Background

It remained lack of a kind of contrast-induced acute kidney injury (CI-AKI) model which was widely used in clinical practice and comparable to CI-AKI in humans.

Methods

Fifty Sprague-Dawley rats were divided into five groups of 10 rats each: (1) sham group (normal saline [NS] + NS); (2) NS plus low osmolality contrast medium (CM15) (NS + CM15); (3) furosemide (FM) plus NS (FM + NS); (4) FM + CM10; and (5) FM + CM15.We measured the levels of serum creatinine (SCr), cystatin C (cys-C) and histopathological scores of kidney tissues.

Results

SCr level in the FM + CM15 group were significantly increased after CM exposure compared with baseline levels (32.9 ± 4.57 vs. 158.7 ± 14.48 μmol/L, p < 0.001). Minor changes were found about the SCr levels between the pre- and post-exposure CM or NS treatment in the other groups. Additionally, the cys-C levels after CM exposure were increased compared with pretreatment levels in the FM + CM15 group (0.08 ± 0.03 vs. 0.18 ± 0.05 mg/L, p < 0.001). Minor changes were noted in the FM + NS group before and after NS administration. Only rats in the FM + CM15 group developed CI-AKI with the definitions of SCr or cys-C. Comparing to the FM + NS group, the histopathological scores were significantly increased in the FM + CM15 group.

Conclusions

A simple and reliable animal model for low osmolality contrast medium-induced AKI was established, which is similar to clinical CI-AKI based on different definitions for AKI.

Simple pre-procedure risk stratification tool for contrast-induced nephropathy

Background

A few simple and pre-procedural risk models have been developed for predicting contrast-induced nephropathy (CIN), which allow for early administration of preventative strategies before coronary angiography (CAG). The study aims to develop and validate simple pre-procedure tools for predicting risk of CIN following CAG.

Methods

We retrospectively analyzed the data from 3,469 consecutive patients undergoing CAG, who were randomly assigned to a development dataset (n=2,313) and a validation dataset (n=1,156). CIN was defined as an increase in serum creatinine (SCr) ≥0.5 mg/dL from baseline within 72 hours after CAG. Multivariate logistic regression was applied to identify independent predictors of CIN to develop risk models. The possible predictors included age >75 years, hypotension, acute myocardial infarction (AMI), SCr ≥1.5 mg/dL, and congestive heart failure (CHF).

Results

The incidences of CIN were 3.20% and 3.55% in the training and validation dataset respectively. Compared to classical Mehran' and ACEF CIN risk score, the new score across the validation dataset exhibited similar discrimination and predictive ability on CIN (c-statistic: 0.829, 0.832, 0.812 respectively) and in-hospital mortality (c-statistic: 0.909, 0.937, 0.866 respectively) (all P>0.05).

Conclusions

The easy-to-use pre-procedural prediction model only containing 5 factors had similar predictive ability on CIN and mortality.

Long-term impact of acute kidney injury on prognosis in patients with acute myocardial infarction

BACKGROUND

Little evidence exists regarding the long-term impact of acute kidney injury (AKI) during index hospitalisation for acute myocardial infarction (AMI). We prospectively assessed the long-term prognostic significance of the occurrence of in-hospital AKI in a multicentre cohort of patients admitted with AMI.

METHODS

Data were obtained from 518 AMI patients with a median follow-up of 5.6 (IQR 4.6-6.5) years. Patients were followed up regarding the occurrence of death, major adverse cardiovascular events (MACE), and any deterioration in kidney function.

RESULTS

From the study cohort, 84 patients (16%) had developed AKI at discharge during index hospitalisation. 96 patients died during follow-up, MACE occurred in 90 patients, and 30 patients showed evidence of deterioration in kidney function. Patients with AKI at hospital discharge had a three-fold increased mortality risk (HR 3.2, 95% CI 2.1-4.8; P < 0.001). This association was independent of possible confounding by variables that could influence prognosis (HR 1.9 95% CI 1.1-3.2; P = 0.028) evident only up to three years during follow-up. During long-term follow-up, patients with AKI during their index hospitalisation had a significantly (P = 0.027) higher incidence of MACE (26%) than those who did not develop AKI (15%). Patients with AKI had a higher incidence of deteriorating kidney function (10%) than those without AKI (5%) during follow-up, but this difference was not significant (P = 0.124).

CONCLUSIONS

Our findings emphasise in addition to the need for appropriate long term follow-up in such patients, an increased mortality and morbidity during the first three years after the index event.

Clinical Implications of Contrast-Induced Nephropathy in Patients Without Baseline Renal Dysfunction Undergoing Coronary Angiography

BACKGROUND

The clinical implications of different definitions of contrast-induced nephropathy (CIN) in patients without baseline renal dysfunction are not well defined.

METHODS

Consecutive patients at a single centre without baseline renal dysfunction (estimated glomerular filtration rate, eGFR≥60ml/min/1.73m²) undergoing coronary angiography or percutaneous coronary intervention (PCI), were systematically evaluated for long-term risk of mortality following CIN using two broad definitions: an absolute increase from baseline in serum creatinine (SCr) ≥0.3mg/dl (mild to severe absolute CIN) and a relative increase from baseline of 25% (mild to severe relative CIN) within 72hours.

RESULT

Of 2,823 subjects alive before discharge following coronary angiography there were 320 episodes of mild to severe relative CIN (11.3%) and 125 of mild to severe absolute CIN (4.4%). During a median follow-up of 2.3years, 73 patients (3.2%) died. After adjustment for confounders, mild to severe absolute CIN was associated with an adjusted hazard ratio (HR) (95% confidence interval) for all-cause mortality of 3.31 (1.74-6.30) (p<0.0001) and relative CIN with an adjusted HR of 1.92 (1.09, 3.38) (p=0.024). The risk of mortality rose with severity of CIN. Two commonly used definitions of CIN combining absolute and relative terms (increase ≥ 0.3mg/dl or 50%, and ≥ 0.5mg/dl or 25% from the baseline) confirmed these results.

CONCLUSION

Among patients without baseline renal dysfunction undergoing coronary angiography, the incidence of CIN can range widely depending on definition. Absolute CIN is less common than relative CIN. Regardless of definition, CIN is associated with a markedly increased risk of long-term mortality. This finding requires confirmation in multicentre studies.

Post-contrast acute kidney injury - Part 1: Definition, clinical features, incidence, role of contrast medium and risk factors : Recommendations for updated ESUR Contrast Medium Safety Committee guidelines

Purpose

The Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) has updated its 2011 guidelines on the prevention of post-contrast acute kidney injury (PC-AKI). The results of the literature review and the recommendations based on it, which were used to prepare the new guidelines, are presented in two papers.

Areas covered in part 1

Topics reviewed include the terminology used, the best way to measure eGFR, the definition of PC-AKI, and the risk factors for PC-AKI, including whether the risk with intravenous and intra-arterial contrast medium differs.

Key Points

• PC-AKI is the preferred term for renal function deterioration after contrast medium.

• PC-AKI has many possible causes.

• The risk of AKI caused by intravascular contrast medium has been overstated.

• Important patient risk factors for PC-AKI are CKD and dehydration.

CT pulmonary angiography in patients with acute or chronic renal insufficiency: Evaluation of a low dose contrast material protocol

Adverse effects of intravenous contrast media (CM) in patients with renal risk factors and acute kidney injury are still controversially discussed. The aim of this study was to investigate whether dual-energy (DE) pulmonary CT angiography (CTPA) in combination with a noise optimized virtual monoenergetic imaging algorithm allows for a reduction of CM. This IRB-approved study comprised 150 patients with suspected pulmonary embolism (78 male; mean age 65 ± 17years). 50 patients with acute/chronic renal failure were examined on a 3^rd generation dual-source CT with an optimized DE CTPA protocol and a low CM injection protocol (5.4 g iodine). 100 further patients were either examined with a standard CTPA protocol or a standard DE CTPA (32 g iodine). For the DE CTPA virtual monoenergetic spectral datasets (40-100 keV) were reconstructed. Main pulmonary arteries at 50 keV and peripheral pulmonary arteries at 40 keV datasets provided the highest contrast-to-noise-ratio (CNR) for both the standard DE CTPA and the optimized protocol, with significantly higher CNR values for the standard DE CTPA protocol (p < 0.05). No pulmonary embolism was missed on the optimized CM protocol. DE CTPA utilizing image reconstruction at 40/50 keV allowed for a reduction of 84% in iodine load while maintaining CNR, which is especially important in patients with acute/chronic renal failure.

Primary percutaneous coronary intervention at centers with and without on-site surgical support: Insights from the Blue Cross Blue Shield of Michigan Cardiovascular Consortium (BMC2)

BACKGROUND

Primary percutaneous coronary intervention (PPCI) is being increasingly performed nationally at sites without on-site cardiac surgery; however, recent guidelines only provide a Class IIa recommendation for this practice. The state of Michigan has permitted PPCI without on-site surgery under a closely monitored system that mandates auditing of all procedures and quarterly feedback on quality and outcomes. This study sought to compare outcomes of patients undergoing PPCI at centers with and without on-site surgery in the state of Michigan.

METHODS

Consecutive patients who underwent PPCI at 47 hospitals in Michigan from January 2010 to December 2015 were included. From this cohort, 4,091 patients from sites with and without on-site cardiac surgery were propensity matched in a 1:1 fashion to compare baseline characteristics, procedural details, and in-hospital outcomes.

RESULTS

Of the 25,886 PPCIs performed at 47 hospitals in Michigan from 2010 to 2015, 21,610 (83.5%) were performed at sites with on-site surgery and 4,276 (16.5%) at sites without on-site surgery. Using propensity score matched cohorts (4,091 patients for each site type), we found no significant differences in baseline characteristics. Overall mortality (5.4% vs 5.8%; P=.442); composite outcome of in-hospital mortality, contrast-induced nephropathy, bleeding, and stroke (13.8% vs 12.8%; P=.152); and individual outcomes within the composite group showed no significant differences. Additionally, there were no clinically meaningful differences in rates of urgent/emergent coronary artery bypass graft or length of stay. Significant differences, however, were found in procedural access site, antiplatelet therapy, contrast volume, and anticoagulant strategy.

CONCLUSIONS

Primary PCI performed at centers with and without cardiac surgery have comparable outcomes and complication rates when performed with close monitoring of quality and outcomes.

Effect of Access Site Choice on Acute Kidney Injury After Percutaneous Coronary Intervention

Acute kidney injury (AKI) after percutaneous coronary intervention (PCI) is associated with worse outcomes. Consecutive patients undergoing PCI between 2005 and 2013 were retrospectively analyzed. Patients undergoing PCI using transfemoral access (TFA) were categorized as the TFA Group, and those using transradial access (TRA) were categorized as the TRA Group. Post-PCI AKI was defined as an increase in serum creatinine >0.5 mg/dl or >25% increase from baseline 48 to 72 hours after the procedure. Independent predictors of post-PCI AKI were identified using inverse probability weighted multivariable analysis. There were 7,529 patients included in the analysis, 5,353 (71%) in the TFA Group and 2,176 (29%) in the TRA Group. Patients in the TRA Group were younger, more likely to be female, taller, heavier and have acute coronary syndrome (ACS) and were less likely to have previous coronary artery bypass graft surgery, cardiogenic shock, and intra-aortic balloon pump use and had shorter fluoroscopy time and less contrast use. Bleeding Academic Research Consortium type 3 or 5 was significantly less frequent in the TRA Group. The primary end point of post-PCI AKI was observed significantly less frequently in the TRA Group compared with the TFA Group (1.1% vs 2.4%, p = 0.001). TRA was independently associated with a lower incidence of post-PCI AKI (odds ratio 0.57, 95% confidence interval 0.35 to 0.91, p = 0.018). In conclusion, access site choice is an independent predictor of post-PCI AKI with a significant risk reduction associated with TRA compared with TFA.

A New Risk Factor Profile for Contrast-Induced Acute Kidney Injury in Patients Who Underwent an Emergency Percutaneous Coronary Intervention

We developed a new risk factor profile for contrast-induced acute kidney injury (CI-AKI) under a new definition in patients who underwent an emergency percutaneous coronary intervention (PCI). Consecutive patients (n = 1061) who underwent an emergency PCI were divided into a derivation group (n = 761) and a validation group (n = 300). The rates of CI-AKI were 23.5% (definition 1: serum creatinine [SCr] increase ≥25% in 72 hours), 4.3% (definition 2: SCr increase ≥44.2 μmol/L in 72 hours), and 7.0% (definition 3: SCr increase ≥44.2 μmol/L in 7 days). Due to the high sensitivity of definition 1 and the high rate of missed cases for late diagnosis of CI-AKI under definition 2, definition 3 was used in the study. The risk factor profile included body surface area <1.6 m2 ( P = .030), transient ischemic attack/stroke history ( P = .001), white blood cell count >15.00 × 109/L ( P = .047), estimated glomerular filtration rate <60 mL/min/1.73 m2 ( P = .002) or baseline SCr >133 μmol/L ( P = .007), intra-aortic balloon pump application ( P = .006), and diuretics administration ( P < .001), showing a significant predictive power in the derivation group and validation group. The new risk factor profile of CI-AKI under a new CI-AKI definition in emergency PCI patients is easily applicable with a useful predictive value.

Association of post-procedural early (within 24h) increases in serum creatinine with all-cause mortality after coronary angiography

BACKGROUND

The majority of patients undergoing coronary angiography (CAG) or percutaneous coronary intervention (PCI) are discharged early, with only early (within 24h) serum creatinine (SCr) data available without evidence of clinical prognosis. We aimed to systemically evaluate the association between post-procedural early increase in SCr and all-cause mortality following CAG.

METHODS

We performed a retrospective sub-study analysis within a prospective observational study including 3091 consecutive patients with baseline and post-procedural early (within 24h) SCr data. The degree (mild, moderate, or large) of absolute and relative increases in SCr from baseline. The mean follow-up time was 2.49years.

RESULT

Moderate or large early increases in SCr were relatively rare (large increase: >1.0mg/dl [0.5%], >100% [0.4%]), whereas mild absolute and relative increases in SCr were more common (mild increase: 0.25 to 0.50mg/dl [4.5%], 25% to 50% [5.9%]). During the follow-up period, there were 136 post-procedural deaths (5.6%). After adjustment for confounders, mild absolute and relative increases in SCr were associated with increased mortality (hazard ratio [HR]: 1.9 and 1.8, respectively, both P<0.05). Moderate or large increases in SCr were associated with higher mortality, even higher than with pre-existing renal dysfunction (HR: 5.36 and 4.12 for moderate increase [0.5 to 1.0mg/dl] and estimated glomerular filtration rate<60ml/min).

CONCLUSION

Post-procedural mild, moderate, or large early increase in SCr, is associated with significantly increased long-term mortality. Although moderate or large increase in SCr following CAG was relatively rare, the prognosis is more serious, and is worse than that of pre-existing renal dysfunction.

CLINICAL TRIAL REGISTRATION

Predictive Value of Contrast Volume to Creatinine Clearance Ratio (PRECOMIN, ClinicalTrials.govNCT01400295).

Protective Effects of Salvianolate on Contrast-Induced Nephropathy after Primary Percutaneous Coronary Intervention: A Prospective Multicenter Randomized Controlled Trial

OBJECTIVES

This study's aim was to evaluate the protective effects of salvianolate on contrast-induced nephropathy after primary percutaneous coronary intervention (PPCI) compared with normal saline (NS) hydration.

METHODS

We enrolled patients with acute myocardial infarction who underwent PPCI in 3 centers in Shanghai. The patients were randomly assigned to the salvianolate group or the NS group. The incidence of CIN, the changes in renal function parameters, and the occurrence of adverse events after the procedure were compared between the 2 groups. We used a multivariate logistic regression analysis to determine the independent correlates of CIN after PPCI.

RESULTS

A total of 484 patients were finally included in the statistical analysis. Compared with the control group, salvianolate reduced the incidence of CIN (9.1 vs. 16.3%, p = 0.018) after PPCI. The renal function parameters after PPCI in the salvianolate group were superior to those of the control group (p < 0.05). The composite adverse events rate was significantly lower in the salvianolate group within 1 month after the procedure (9.5 vs. 15.5%, p = 0.046). A higher peak of troponin I and loop diuretic therapy were the independent correlates of CIN after PPCI.

CONCLUSIONS

Salvianolate reduces the incidence of CIN and protects renal function after PPCI, and the effects were superior to those of NS hydration.

Acute Kidney Injury After Radial or Femoral Access for Invasive Acute Coronary Syndrome Management: AKI-MATRIX

BACKGROUND

It remains unclear whether radial access (RA), compared with femoral access (FA), mitigates the risk of acute kidney injury (AKI).

OBJECTIVES

The authors assessed the incidence of AKI in patients with acute coronary syndrome (ACS) enrolled in the MATRIX-Access (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of Angiox) trial.

METHODS

Among 8,404 patients, 194 (2.3%) were excluded due to missing creatinine values, no or an incomplete coronary angiogram, or previous dialysis. The primary AKI-MATRIX endpoint was AKI, defined as an absolute (>0.5 mg/dl) or a relative (>25%) increase in serum creatinine (sCr).

RESULTS

AKI occurred in 634 patients (15.4%) with RA and 712 patients (17.4%) with FA (odds ratio [OR]: 0.87; 95% confidence interval [CI]: 0.77 to 0.98; p = 0.0181). A >25% sCr increase was noted in 633 patients (15.4%) with RA and 710 patients (17.3%) with FA (OR: 0.87; 95% CI: 0.77 to 0.98; p = 0.0195), whereas a >0.5 mg/dl absolute sCr increase occurred in 175 patients (4.3%) with RA versus 223 patients (5.4%) with FA (OR: 0.77; 95% CI: 0.63 to 0.95; p = 0.0131). By implementing the Kidney Disease Improving Global Outcomes criteria, AKI was 3-fold less prevalent and trended lower with RA (OR: 0.85; 95% CI: 0.70 to 1.03; p = 0.090), with stage 3 AKI occurring in 28 patients (0.68%) with RA versus 46 patients (1.12%) with FA (p = 0.0367). Post-intervention dialysis was needed in 6 patients (0.15%) with RA and 14 patients (0.34%) with FA (p = 0.0814). Stratified analyses suggested greater benefit with RA than FA in patients at greater risk for AKI.

CONCLUSIONS

In ACS patients who underwent invasive management, RA was associated with a reduced risk of AKI compared with FA. (Minimizing Adverse Haemorrhagic Events by TRansradial Access Site and Systemic Implementation of angioX [MATRIX]; NCT01433627).

Percutaneous Coronary Intervention Versus Optimal Medical Therapy for Stable Angina in Advanced CKD: A Decision Analysis

BACKGROUND

Percutaneous coronary intervention (PCI) use is low in the setting of stable symptomatic angina in individuals with advanced chronic kidney disease (CKD) despite high cardiovascular risk in this population, and PCI is frequently deferred out of concern for precipitating dialysis therapy. Whether this is appropriate is uncertain, and patient-centered data comparing the relative risks and benefits of continued medical therapy versus PCI in patients with advanced CKD and stable angina are scarce.

STUDY DESIGN

Decision analysis.

SETTING & POPULATION

Hypothetical cohort of individuals with advanced CKD (stages 4-5 with estimated glomerular filtration rates ≤ 20mL/min/1.73m2) and stable angina.

MODEL, PERSPECTIVE, & TIMELINE

A Markov model with a Monte Carlo simulation through 12 cycles, that is, 3 years of 3-month intervals, with 10,000 microsimulations predicted mean quality-adjusted life-years.

INTERVENTION

PCI first, medical management, or dialysis (hemodialysis [HD]) followed by PCI.

OUTCOMES

Outcomes modeled were progression to HD therapy (for those not assigned to the preemptive HD strategy), catheter infection, and death.

RESULTS

Our analysis showed mean quality-adjusted life-years of 1.103 ± 0.69 for PCI first, 1.088±0.70 for medical management, and 0.670±0.58 for HD followed by PCI. Probabilistic sensitivity analysis found PCI as the preferred strategy > 60% of the time.

LIMITATIONS

Values for probabilities and utilities were estimated and/or derived from multiple sources that were not uniform in their populations in terms of age, comorbid condition burden, and degree of kidney failure, and several simplifying assumptions were made.

CONCLUSIONS

Our analysis demonstrates that quality-adjusted life expectancy is similar for the PCI first and medical management strategies in patients with advanced CKD with stable angina and that the decision depends on patient preferences other than those incorporated in our model. Both strategies are superior to preemptive dialysis.

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.

Canada Acute Coronary Syndrome Score: A Preprocedural Risk Score for Contrast-Induced Nephropathy After Primary Percutaneous Coronary Intervention

In patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention, contrast-induced nephropathy (CIN) is a serious complication associated with poor outcomes. We assessed the predictive value of the Canada Acute Coronary Syndrome (C-ACS) score for CIN in these patients. A total of 394 consecutive patients with STEMI were enrolled and divided into 3 groups according to their C-ACS scores—group 1, score 0; group 2, score 1; and group 3, score ≥2. The clinical outcomes were CIN and major adverse clinical events (MACEs) during hospital and follow-up; 8.4% of patients developed CIN. Patients with high C-ACS scores were more likely to develop CIN, in-hospital death, and MACEs ( P < .001). The C-ACS score was an independent predictor of CIN (odds ratio = 2.87; 95% confidence interval = 1.78-4.63; P < .001) and risk factor for long-term MACEs. The C-ACS score had good predictive values for CIN, in-hospital morality, MACEs, and long-term mortality. Patients with high C-ACS risk scores exhibited a worse survival rate than those with low scores (death, P = .02; MACEs, P = .006). In conclusion, in patients with STEMI, the C-ACS could predict CIN and clinical outcomes.

Use of Both Serum Cystatin C and Creatinine as Diagnostic Criteria for Contrast-Induced Acute Kidney Injury and Its Clinical Implications

BACKGROUND

Contrast-induced acute kidney injury (CI-AKI) was traditionally defined as an increase in serum creatinine (sCr) after contrast media exposure. Recently, serum cystatin C (sCyC) has been proposed as an alternative to detect acute changes in renal function. The clinical implications of combining sCyC and sCr to diagnose CI-AKI remain unknown.

METHODS AND RESULTS

One thousand seventy-one consecutive patients undergoing coronary angiography/intervention were prospectively enrolled. SCyC and sCr were assessed at baseline and 24 to 48 hours after contrast media exposure. CI-AKI determined by sCr (CI-AKI_sCr) was defined as an sCr increase greater than 0.3 mg/dL or 50% from baseline. Major adverse events at 12 months were assessed. CI-AKI_sCr developed in 25 patients (2.3%). Twelve-month follow-up was available for 1063 patients; major adverse events occurred in 61 patients (5.7%). By receiver operating characteristic curve analysis, an sCyC increase of greater than 15% was the optimal cutoff for CI-AKI_sCr detection, which occurred in 187 patients (17.4%). To evaluate the use of both sCyC and sCr as CI-AKI diagnostic criteria, we stratified patients into 3 groups: no CI-AKI, CI-AKI detected by a single marker, and CI-AKI detected by both markers. Multivariable logistic regression revealed that the predictability of major adverse events increased in a stepwise fashion in the 3 groups (no-CI-AKI group as the reference, CI-AKI detected by a single marker: odds ratio=2.25, 95% CI: 1.24-4.10, P<0.01; CI-AKI detected by both markers: odds ratio=10.00, 95% CI: 3.13-31.91, P<0.001).

CONCLUSIONS

Combining sCyC and sCr to diagnose CI-AKI would be beneficial for risk stratification and prognosis in patients after contrast media exposure.

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.

Renal assessment using CKD-EPI equation is useful as an early predictor of contrast- induced nephropathy in elderly patients with cancer

OBJECTIVES

To assess respective roles of serum creatinine (SCr) alone and estimated glomerular filtration rate (eGFR) as an early predictor for contrast-induced nephropathy (CIN) in elderly patients with cancer.

MATERIALS AND METHODS

eGFR of 348 patients at 65years or older with malignancy who underwent contrast-enhanced computed tomography (CECT) were calculated. eGFR was calculated based on the following three equations: Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI); Modification of Diet in Renal Disease Study (MDRD); Cockcroft-Gault (CG). CIN was subdivided into two groups: CIN_25% (SCr increase >25% but ≤0.5mg/dl), and CIN_0.5 (SCr increase >0.5mg/dl). The occurrence and clinical outcomes of CIN were determined according to SCr and eGFR.

RESULTS

After CECT, CIN occurred in 50 (14.4%) patients, including 33 CIN_25% patients and 17 CIN_0.5 patients. CIN_0.5 was significantly correlated with prolonged hospitalizations and increased in-hospital mortality, but not CIN_25%. Despite SCr<1.5mg/dl, preexisting renal insufficiency (RI) was observed in 47 (13.5%) patients based on CKD-EPI equation, 50 (14.4%) patients based on MDRD equation, and 144 (41.4%) patients based on CG formula. In preexisting RI, the prevalence of CIN_0.5 had an odds ratio of 15.02 (5.24 to 43.07) based on CKD-EPI equation, 13.73 (4.81 to 39.20) based on MDRD equation, and 5.03 (1.60 to 15.75) based on CG formula.

CONCLUSION

In elderly patients with cancer who visit the emergency department, renal assessment before CECT using CKD-EPI equation was superior to SCr alone, MDRD equation, or CG formula in predicting the occurrence of CIN related CECT.

Does N-terminal pro-brain natriuretic peptide add prognostic value to the Mehran risk score for contrast-induced nephropathy and long-term outcomes after primary percutaneous coronary intervention?

PURPOSE

To evaluate the prognostic value of plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) in relation to Mehran risk score (MRS) for contrast-induced nephropathy (CIN) in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI).

METHODS

We prospectively enrolled 283 consecutive patients treated with PPCI for STEMI. NT-proBNP was measured, and the MRS was calculated. The primary end point was CIN, defined as an absolute increase in serum creatinine ≥0.5 mg/dL from baseline within 48-72 h after contrast medium exposure.

RESULTS

The incidence of CIN was 9.2 %. Patients with CIN had higher NT-proBNP and MRS than those without CIN. The value of NT-proBNP was similar to MRS for CIN (C statistics 0.760 vs. 0.793, p = 0.689). After adjustment for MRS, elevated NT-proBNP (defined as the best cutoff point) was significantly associated with CIN. The addition of elevated NT-proBNP to MRS did not significantly improve the C statistics, over that with the original MRS model (0.833 vs. 0.793, p = 0.256). In addition, similar results were observed for in-hospital and long-term major adverse clinical events.

CONCLUSIONS

Although NT-proBNP did not add any prognostic value to the MRS model for CIN, NT-proBNP, as a simple biomarker, was similar to MRS, and may be another useful and rapid screening tool for CIN and death risk assessment, identifying subjects who need therapeutic measures to prevent CIN.

Acute Kidney Injury Definition and In-Hospital Mortality in Patients Undergoing Primary Percutaneous Coronary Intervention for ST-Segment Elevation Myocardial Infarction

BACKGROUND

Acute kidney injury (AKI) has been associated with increased mortality in ST-segment elevation myocardial infarction. We compared the mortality predictive accuracy of the 3 AKI definitions used most widely for patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention.

METHODS AND RESULTS

We included 3771 patients with ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention at 2 Italian hospitals. AKI incidence was evaluated according to creatinine increases of ≥25% (AKI-25), ≥0.3 mg/dL (AKI-0.3), and ≥0.5 mg/dL (AKI-0.5). The primary end point was in-hospital mortality. Overall, 557 (15%), 522 (14%), and 270 (7%) patients developed AKI-25, AKI-0.3, and AKI-0.5, respectively (P<0.01). All AKI definitions independently predicted in-hospital mortality (adjusted odds ratio 4.9 [95% CI 3.1-7.8], 5.4 [95% CI 3.3-8.6], and 8.3 [95% CI 5.1-13.3], respectively; P<0.01 for all). At receiver operating characteristic analysis, the addition of each AKI definition to combined clinical predictors of mortality (age, sex, left ventricular ejection fraction, admission creatinine, creatine kinase-MB peak) found at stepwise analysis significantly improved mortality prognostication (area under the curve increased from 0.89 for clinical predictor combination alone to 0.92 for AKI-25, 0.92 for AKI-0.3, and 0.93 for AKI-0.5; P<0.01 for all). At reclassification analysis, AKI-0.5 added to clinical predictors, provided the highest score in mortality (net reclassification improvement +10% versus AKI-0.3 [P=0.01] and +8% versus AKI-25 [P=0.05]).

CONCLUSIONS

Each AKI definition significantly improved the mortality prediction beyond major clinical variables. AKI-0.5 showed a mortality discrimination advantage, suggesting it should be the preferred definition in studies addressing ST-segment elevation myocardial infarction and focusing on short-term mortality.

Comparison of Different Risk Scores for Predicting Contrast Induced Nephropathy and Outcomes After Primary Percutaneous Coronary Intervention in Patients With ST Elevation Myocardial Infarction

Accurate risk stratification for contrast-induced nephropathy (CIN) is important for patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). We aimed to compare the prognostic value of validated risk scores for CIN. We prospectively enrolled 422 consecutive patients with STEMI undergoing PPCI. Mehran; Gao; Chen; age, serum creatinine (SCr), or glomerular filtration rate, and ejection fraction (ACEF or AGEF); and Global Registry for Acute Coronary Events risk scores were calculated for each patient. The prognostic accuracy of the 6 scores for CIN, and in-hospital and 3-year all-cause mortality and major adverse clinical events (MACEs), was assessed using the c-statistic for discrimination and the Hosmer-Lemeshow test for calibration. CIN was defined as either CIN-narrow (increase in SCr ≥0.5 mg/dl) or CIN broad (≥0.5 mg/dl and/or a ≥25% increase in baseline SCr). All risk scores had relatively high predictive values for CIN-narrow (c-statistic: 0.746 to 0.873) and performed well for prediction of in-hospital death (0.784 to 0.936), MACEs (0.685 to 0.763), and 3-year all-cause mortality (0.655 to 0.871). The ACEF and AGEF risk scores had better discrimination and calibration for CIN-narrow and in-hospital outcomes. However, all risk score exhibited low predictive accuracy for CIN-broad (0.555 to 0.643) and 3-year MACEs (0.541 to 0.619). In conclusion, risk scores for predicting CIN perform well in stratifying the risk of CIN-narrow, in-hospital death or MACEs, and 3-year all-cause mortality in patients with STEMI undergoing PPCI. The ACEF and AGEF risk scores appear to have greater prognostic value.

The optimal definition of contrast-induced acute kidney injury for prediction of inpatient mortality in patients undergoing percutaneous coronary interventions

BACKGROUND

It is unknown which definition of contrast-induced acute kidney injury (CI-AKI) in the setting of percutaneous coronary interventions is best associated with inpatient mortality and whether this association is stable across patients with various preprocedural serum creatinine (SCr) values.

METHODS

We applied logistic regression models to multiple CI-AKI definitions used by the Kidney Disease Improving Global Outcomes guidelines and previously published studies to examine the impact of preprocedural SCr on a candidate definition's correlation with the adverse outcome of inpatient mortality. We used likelihood ratio tests to examine candidate definitions and identify those where association with inpatient mortality remained constant regardless of preprocedural SCr. These definitions were assessed for specificity, sensitivity, and positive and negative predictive values to identify an optimal definition.

RESULTS

Our study cohort included 119,554 patients who underwent percutaneous coronary intervention in Michigan between 2010 and 2014. Most commonly used definitions were not associated with inpatient mortality in a constant fashion across various preprocedural SCr values. Of the 266 candidate definitions examined, 16 definition's association with inpatient mortality was not significantly altered by preprocedural SCr. Contrast-induced acute kidney injury defined as an absolute increase of SCr ≥0.3 mg/dL and a relative SCr increase ≥50% was selected as the optimal candidate using Perkins and Shisterman decision theoretic optimality criteria and was highly predictive of and specific for inpatient mortality.

CONCLUSIONS

We identified the optimal definition for CI-AKI to be an absolute increase in SCr ≥0.3 mg/dL and a relative SCr increase ≥50%. Further work is needed to validate this definition in independent studies and to establish its utility for clinical trials and quality improvement efforts.

Safe limits of contrast vary with hydration volume for prevention of contrast-induced nephropathy after coronary angiography among patients with a relatively low risk of contrast-induced nephropathy

BACKGROUND

Few studies have investigated the safe limits of contrast to prevent contrast-induced nephropathy (CIN) based on hydration data. We aimed to investigate the relative safe maximum contrast volume adjusted for hydration volume in a population with a relatively low risk of CIN.

METHODS AND RESULTS

The ratios of contrast volume-to-creatinine clearance (V/CrCl) and hydration volume to body weight (HV/W) were determined in patients undergoing cardiac catheterization. Receiver-operator characteristic curve analysis based on the maximum Youden index was used to identify the optimal cutoff for V/CrCl in all patients and in HV/W subgroups. Eighty-six of 3273 (2.6%) patients with mean CrCl 71.89±27.02 mL/min developed CIN. Receiver-operator characteristic curve analysis indicated that a V/CrCl ratio of 2.44 was a fair discriminator for CIN in all patients (sensitivity, 73.3%; specificity, 70.4%). After adjustment for other confounders, V/CrCl >2.44 continued to be significantly associated with CIN (adjusted odds ratio, 4.12; P<0.001) and the risk of death (adjusted hazard ratio, 2.62; P<0.001). The mean HV/W was 12.18±7.40. We divided the patients into 2 groups (HV/W ≤12 and >12 mL/kg). The best cutoff value for V/CrCl was 1.87 (sensitivity, 67.9%; specificity, 64.4%; adjusted odds ratio, 3.24; P=0.011) in the insufficient hydration subgroup (HV/W, ≤12 mL/kg; CIN, 1.32%) and 2.93 (sensitivity, 69.0%; specificity, 65.0%; adjusted odds ratio, 3.04; P=0.004) in the sufficient hydration subgroup (HV/W, >12 mL/kg; CIN, 5.00%).

CONCLUSIONS

The V/CrCl ratio adjusted for HV/W may be a more reliable predictor of CIN and even long-term outcomes after cardiac catheterization. We also found a higher best cutoff value for V/CrCl to predict CIN in patients with a relatively sufficient hydration status, which may be beneficial during decision-making about contrast dose limits in relatively low-risk patients with different hydration statuses.

Association between acute kidney injury and in-hospital mortality in patients undergoing percutaneous coronary interventions

BACKGROUND

Acute kidney injury (AKI) post percutaneous coronary intervention (PCI) is associated with increased mortality but both death and AKI share common risk factors. Moreover, the effect of a high contrast dose, a known modifiable risk factor for AKI, on mortality is unknown. The aim of our study was to analyze the association between AKI and in-hospital mortality post PCI after adjustment for confounding by common risk factors.

METHODS AND RESULTS

This study was performed using a regional registry of all patients undergoing PCI in Michigan. Primary end points were AKI (serum creatinine increase >0.5 mg/dL) and all-cause in-hospital mortality. Propensity matching was performed, with each AKI patient matched to 4 controls. Attributable risk fraction and the exposed index number of AKI for mortality were calculated within the propensity-matched cohort. Between 2010 and 2013, 92 317 patients underwent PCI, of whom 2141 (2.3%) developed AKI. We matched 1371/2141 patients with AKI to 5484 controls. AKI was strongly associated with mortality (odds ratio=12.52, 95% confidence interval 9.29-16.86) in the propensity-matched cohort. The attributable risk fraction for mortality of AKI was 31.4% (95% confidence interval 26.8%-37.5%), and one death could be prevented for every 9 cases of AKI successfully avoided. The independent impact of a high contrast dose at time of PCI on in-hospital mortality risk was weak (adjusted odds ratio 1.19, 95% confidence interval 0.97-1.45).

CONCLUSIONS

Nearly one-third of the in-hospital mortality post PCI is attributable to AKI. Preventing 9 cases of AKI could potentially prevent one death. These study findings stress the need for developing effective AKI preventive strategies beyond minimization of contrast dose.