Maintaining a National Acute Kidney Injury Risk Prediction Model to Support Local Quality Benchmarking.

BACKGROUND: The utility of quality dashboards to inform decision-making and improve clinical outcomes is tightly linked to the accuracy of the information they provide and, in turn, accuracy of underlying prediction models. Despite recognition of the need to update prediction models to maintain accuracy over time, there is limited guidance on updating strategies. We compare predefined and surveillance-based updating strategies applied to a model supporting quality evaluations among US veterans. METHODS: We evaluated the performance of a US Department of Veterans Affairs-specific model for postcardiac catheterization acute kidney injury using routinely collected observational data over the 6 years following model development (n=90 295 procedures in 2013-2019). Predicted probabilities were generated from the original model, an annually retrained model, and a surveillance-based approach that monitored performance to inform the timing and method of updates. We evaluated how updating the national model impacted regional quality profiles. We compared observed-to-expected outcome ratios, where values above and below 1 indicated more and fewer adverse outcomes than expected, respectively. RESULTS: The original model overpredicted risk at the national level (observed-to-expected outcome ratio, 0.75 [0.74-0.77]). Annual retraining updated the model 5×; surveillance-based updating retrained once and recalibrated twice. While both strategies improved performance, the surveillance-based approach provided superior calibration (observed-to-expected outcome ratio, 1.01 [0.99-1.03] versus 0.94 [0.92-0.96]). Overprediction by the original model led to optimistic quality assessments, incorrectly indicating most of the US Department of Veterans Affairs' 18 regions observed fewer acute kidney injury events than predicted. Both updating strategies revealed 16 regions performed as expected and 2 regions increasingly underperformed, having more acute kidney injury events than predicted. CONCLUSIONS: Miscalibrated clinical prediction models provide inaccurate pictures of performance across clinical units, and degrading calibration further complicates our understanding of quality. Updating strategies tailored to health system needs and capacity should be incorporated into model implementation plans to promote the utility and longevity of quality reporting tools.

Acute Kidney Injury and Renin-Angiotensin System Inhibition Following Transcatheter Aortic Valve Replacement.

OBJECTIVE: To identify renin-angiotensin system (RAS) inhibition utilization and discontinuation after transcatheter aortic valve replacement (TAVR) and identify predictors of use and discontinuation. BACKGROUND: RAS inhibition after TAVR has been associated with lower cardiac mortality and heart failure readmissions. METHODS: We analyzed 735 consecutive TAVR patients (2014-2019) who survived to hospital discharge at a high-volume TAVR center to determine the utilization and discontinuation of RAS inhibition after TAVR and identify predictors of use and discontinuation. Clinical characteristics, procedural variables, and hospital outcomes were compared between patients receiving vs not receiving discharge RAS inhibitors. Data were compared using t-test and Chi-square test. Multivariable analysis was used to determine independent clinical predictors. RESULTS: Of the 735 patients, 41.9% were discharged with at least 1 RAS inhibitor. In TAVR patients with heart failure with reduced ejection fraction (HFrEF), defined as EF ≤40%, the utilization of RAS inhibitors at discharge was 51.1%. Patients receiving discharge RAS inhibitors had lower incidences of acute kidney injury (AKI) post procedure (8.1% vs 17.8%; P<.01). Discontinuation of RAS inhibition was observed in approximately 1 in 3 patients and was associated with AKI and pacemaker requirement. Three predictors of RAS inhibitor utilization were higher systolic blood pressure, RAS inhibitor use prior to TAVR, and HFrEF. Conversely, new pacemaker and AKI were associated with less utilization of RAS inhibitors; patients developing AKI were 74% less likely to receive RAS inhibitors than those without AKI. CONCLUSION: Decreased RAS inhibition provides a potential mechanism for worse outcomes in TAVR patients who develop AKI.

Antineutrophil Cytoplasmic Autoantibody-Associated Vasculitis with Kidney Involvement in a Patient with AL Amyloidosis.

Antineutrophil cytoplasmic autoantibody (ANCA) vasculitis has occasionally been associated with other systemic glomerulonephritis, such as anti-glomerular basement membrane disease. Here, we report the first clinical case of ANCA-associated crescentic glomerulonephritis with AL amyloidosis. An 81-years-old gentleman presented to the hospital with acute kidney injury (serum creatinine 4.7 mg/dL) on a background of chronic kidney disease and volume overload. Autoimmune serology was remarkable for p-ANCA and myeloperoxidase positivity. A renal biopsy confirmed pauci-immune glomerulonephritis and lambda light-chain amyloid deposition (confirmed on liquid chromatography and tandem mass spectrometry). The patient was initially managed with rituximab and subsequently transitioned to bortezomib-based chemotherapy but died due to decompensated heart failure. This case report promotes greater awareness of the unusual presentation of amyloidosis and guides future research and treatment.

Effect of Low-Frequency Therapeutic Ultrasound on Induction of Nitric Oxide in CKD: Potential to Prevent Acute Kidney Injury.

INTRODUCTION: Post-contrast acute kidney injury (PC-AKI) develops in a significant proportion of patients with CKD after invasive cardiology procedures and is strongly associated with adverse outcomes. OBJECTIVE: We sought to determine whether increased intrarenal nitric oxide (NO) would prevent PC-AKI. METHODS: To create a large animal model of CKD, we infused 250 micron particles into the renal arteries in 56 ± 8 kg pigs. We used a low-frequency therapeutic ultrasound device (LOTUS - 29 kHz, 0.4 W/cm2) to induce NO release. NO and laser Doppler probes were used to assess changes in NO content and blood flow. Glomerular filtration rate (GFR) was measured by technetium-diethylene-triamine-pentaacetic acid (Tc-99m-DTPA) radionuclide imaging. PC-AKI was induced by intravenous infusion of 7 cm3/kg diatrizoate. In patients with CKD, we measured GFR at baseline and during LOTUS using Tc-99m-DTPA radionuclide imaging. RESULTS: In the pig model, CKD developed over 4 weeks (serum creatinine [Cr], mg/dL, 1.0 ± 0.2-2.6 ± 0.9, p < 0.01, n = 12). NO and renal blood flow (RBF) increased in cortex and medulla during LOTUS. GFR increased 75 ± 24% (p = 0.016, n = 3). PC-AKI developed following diatrizoate i.v. infusion (Cr 2.6 ± 0.7 baseline to 3.4 ± 0.6 at 24 h, p < 0.01, n = 3). LOTUS (starting 15 min prior to contrast and lasting for 90 min) prevented PC-AKI in the same animals 1 week later (Cr 2.5 ± 0.4 baseline to 2.6 ± 0.7 at 24 h, p = ns, n = 3). In patients with CKD (n = 10), there was an overall 25% increase in GFR in response to LOTUS (p < 0.01). CONCLUSIONS: LOTUS increased intrarenal NO, RBF, and GFR and prevented PC-AKI in a large animal model of CKD, and significantly increased GFR in patients with CKD. This novel approach may provide a noninvasive nonpharmacological means to prevent PC-AKI in high-risk patients.

Acute Kidney Recovery in Patients Who Underwent Transcatheter Versus Surgical Aortic Valve Replacement (from the Northern New England Cardiovascular Disease Study Group).

Acute kidney recovery (AKR) is a recently described phenomenon observed after transcatheter aortic valve replacement (TAVR) and is more frequent than acute kidney injury (AKI). To determine the incidence and predictors of AKR between surgical aortic valve replacement (SAVR) and TAVR, we examined patients with chronic kidney disease and severe aortic stenosis who underwent SAVR or TAVR procedure between 2007 and 2017; excluding age <65 or >90, dialysis, endocarditis, non-aortic valve stenosis, or patients died within 48-hours postprocedure. AKR was defined as an increase of estimated glomerular filtration rate (eGFR) >25% and AKI as decrease in eGFR >25% at discharge. Stroke, mortality, major bleeding, transfusion, and length of stay were examined. Multivariate logistic regression analysis was used to examine predictors of AKR. There were 750 transcatheter and 1,062 surgical patients and 319 pairs after propensity matching. AKR was observed in 26% TAVR versus 23.2% SAVR, p = 0.062. Highest recovery was in patients with eGFR <30 for both TAVR (33.7%) and SAVR (34.5%) patients. Independent predictors of AKR were ejection fraction <50% (odds ratio [OR] 1.66, 95% confidence interval [CI] 1.02 to 2.71, p = 0.042), female gender (OR 1.66, 95% CI 1.1 to 2.5, p = 0.015), and obesity (OR 1.5, 95% CI 1.04-2.3, p = 0.032). Diabetes was a negative predictor of AKR (OR 0.55, 95% CI 0.36 to 0.84, p = 0.005). AKR was associated with improved secondary clinical outcomes compared with AKI. In conclusion, AKR is a generalizable phenomenon occurring frequently and similarly among transcatheter or surgical aortic valve patients. Diabetes is a negative predictor of AKR, possibly indicative of less reversible kidney disease.

Recovery of Kidney Dysfunction After Transcatheter Aortic Valve Implantation (from the Northern New England Cardiovascular Disease Study Group).

Acute Kidney Recovery (AKR) is a potential benefit of transcatheter aortic valve implantation (TAVI). We determined the incidence and predictors of AKR in a multicenter prospective registry of TAVI. After excluding patients on dialysis or who died within 48 hours postprocedure, we reviewed 1,502 consecutive patients underwent TAVI in Northern New England from 2012 to 2017. Patients were categorized into 3 groups based on the change in postprocedure estimated glomerular filtration rate (eGFR): Acute Kidney Injury (AKI, decrease in eGFR >25%), AKR (increase in eGFR >25%) or no change in kidney function on discharge creatinine following TAVI. We then focused in patients with baseline chronic kidney disease (CKD defined as eGFR ≤60 ml/min; n = 755) and developed multivariate predictor models to determine the clinical and procedural variables associated with AKR. For the TAVI cohort (n = 1,502), the overall incidence of AKR was 17.8%. AKR was threefold higher in patients with eGFR ≤60 ml/min as compared to those with eGFR >60 ml/min (26.6% vs 8.9%, p < 0.001). In the CKD population, hospital complications were similar among patients with no change in renal function and AKR; patients with AKI had a higher rate of hospital mortality, pacemaker implantation, length of hospitalization, and transfusions. Using multivariable logistic regression, moderate to severe lung disease, eGFR < 50 ml/min and previous aortic valve surgery were found to be independent predictors of AKR. Patients with diabetes mellitus, baseline anemia, and Society of thoracic surgeons score >6.1 were less likely to develop AKR. In conclusion, AKR occurred in 1 of 4 of all TAVI patients with baseline CKD and was a more frequent phenomena than AKI. Patients with decreased lung function, previous aortic valve surgery and worse baseline renal function were more likely to demonstrate AKR, whereas patients with diabetes mellitus, baseline anemia, and higher Society of thoracic risk scores were less likely to see improvements in renal function after TAVI.

Frequency and Prognostic Significance of Acute Kidney Recovery in Patients Who Underwent Transcatheter Aortic Valve Implantation.

Acute kidney injury (AKI) after transcatheter aortic valve implantation (TAVI) is associated with increased mortality. As significant hemodynamic improvement may occur with relief of aortic stenosis, we hypothesized that TAVI patients may demonstrate the opposite phenomena: acute kidney recovery (AKR). We studied the incidence and predictors of AKR in post-TAVI patients. A total of 366 consecutive patients underwent TAVI (January 2012 to January 2017) at a single center. We defined AKR as a 25% improvement in glomerular filtration rate (GFR) at 48 hours after TAVI. AKI-creatinine (Cr) was defined as an increase in Cr of ≥0.3 mg/dl at 48 hours. Patients were categorized in 3 groups: AKR (≥25% increase in GFR), unchanged GFR, and AKI-GFR (inverse definition of AKR, ≥25% decrease in GFR). Multivariable logistic regression defined independent predictors of AKR. AKR occurred in 1/3 of patients. AKI-Cr occurred in 13% of patients, whereas AKI-GFR occurred similarly in 15%. AKR and AKI occurred most frequently in patients with chronic kidney disease (CKD: GFR ≤ 60 ml/min/1.73 m2). Independent predictors of AKR-GFR by multivariable analysis were male gender, lack of chronic ß-blocker utilization, and presence of CKD. Notably, left ventricular dysfunction and contrast volume were not predictive of AKR. Transfusion occurred less frequently among patients with AKR compared with patients with AKI-GFR (11% vs 26%, p = 0.03). Death occurred in 0% of AKR patients versus 9.3% of AKI-GFR patients (p <0.01). In conclusion, this is the first report of AKR after TAVI. Patients with CKD, male gender, and lack of pre-TAVI beta blockade were more likely to demonstrate AKR.

Examination of Prepregnancy and Pregnancy Urinary Protein Levels in Healthy Nulliparous Women.

During pregnancy, abnormal proteinuria is defined as urine protein excretion greater than 300 mg/24 h. Although widely accepted, this definition is not based on clinical outcomes. Our study aimed to longitudinally examine proteinuria in healthy women prior to, and in late pregnancy and to compare inpatient and outpatient 24-hour urine collections. Nulliparous women planning to conceive were recruited and completed a 24-hour urinary collection. Those who subsequently conceived completed a second 24-hour urinary collection in late pregnancy. In the first 5 years of the study, urinary collections were completed during an inpatient admission; all collections during the latter part of the study were performed as outpatients. Urine protein was measured using the VITROS UPRO Slide kit. Wilcoxon signed rank tests were used for paired comparisons of prepregnancy and late pregnancy proteinuria and Wilcoxon rank sum tests were used to compare inpatient and outpatient collections. Among 134 women completing a prepregnancy collection, median urinary protein excretion was 188 mg/24 h (IQR 103-280). Sixty-five women subsequently conceived and completed a late pregnancy collection. In healthy women, urinary protein increased to 254 mg/24 h during pregnancy (IQR 166-396). Forty-five percent of women exceeded the defined normal threshold of proteinuria in 24 hours in the absence of disease. Inpatient collections resulted in higher levels of urinary protein than outpatient at both time points. Our data suggest that significant proteinuria is present in healthy nonpregnant women. Even in the absence of disease, proteinuria increases during pregnancy. Outpatient collections may underestimate proteinuria, especially in late pregnancy.

Chronic Kidney Disease Progression and Cardiovascular Outcomes Following Cardiac Catheterization-A Population-Controlled Study.

BACKGROUND: Studies of kidney disease associated with cardiac catheterization typically rely on billing records rather than laboratory data. We examined the associations between percutaneous coronary interventions, acute kidney injury, and chronic kidney disease progression using comprehensive Veterans Affairs clinical and laboratory databases. METHODS AND RESULTS: Patients undergoing percutaneous coronary interventions between 2005 and 2010 (N=24 405) were identified in the Veterans Affairs Clinical Assessment, Reporting, and Tracking registry and examined for associated acute kidney injury and chronic kidney disease development or progression relative to 24 405 matched population controls. Secondary outcomes analyzed included dialysis, acute myocardial infarction, and mortality. The incidence of chronic kidney disease progression following percutaneous coronary interventions complicated by acute kidney injury, following uncomplicated coronary interventions, and in matched controls were 28.66, 11.15, and 6.81 per 100 person-years, respectively. Percutaneous coronary intervention also increased the likelihood of chronic kidney disease progression in both the presence and absence of acute injury relative to controls in adjusted analyses (hazard ratio [HR], 5.02 [95% CI, 4.68-5.39]; and HR, 1.76 [95% CI, 1.70-1.86]). Among patients with estimated glomerular filtration rate <60 mL/min per 1.73 m2, acute kidney injury increased the likelihood of disease progression by 8-fold. Similar results were observed for all secondary outcomes. CONCLUSIONS: Acute kidney injury following percutaneous coronary intervention was associated with increased chronic kidney disease development and progression and mortality.

Meta-Analysis of Individual Patient Data of Sodium Bicarbonate and Sodium Chloride for All-Cause Mortality After Coronary Angiography.

We sought to examine the relation between sodium bicarbonate prophylaxis for contrast-associated nephropathy (CAN) and mortality. We conducted an individual patient data meta-analysis from multiple randomized controlled trials. We obtained individual patient data sets for 7 of 10 eligible trials (2,292 of 2,764 participants). For the remaining 3 trials, time-to-event data were imputed based on follow-up periods described in their original reports. We included all trials that compared periprocedural intravenous sodium bicarbonate to periprocedural intravenous sodium chloride in patients undergoing coronary angiography or other intra-arterial interventions. Included trials were determined by consensus according to predefined eligibility criteria. The primary outcome was all-cause mortality hazard, defined as time from randomization to death. In 10 trials with a total of 2,764 participants, sodium bicarbonate was associated with lower mortality hazard than sodium chloride at 1 year (hazard ratio 0.61, 95% confidence interval [CI] 0.41 to 0.89, p = 0.011). Although periprocedural sodium bicarbonate was associated with a reduction in the incidence of CAN (relative risk 0.75, 95% CI 0.62 to 0.91, p = 0.003), there exists a statistically significant interaction between the effect on mortality and the occurrence of CAN (hazard ratio 5.65, 95% CI 3.58 to 8.92, p <0.001) for up to 1-year mortality. Periprocedural intravenous sodium bicarbonate seems to be associated with a reduction in long-term mortality in patients undergoing coronary angiography or other intra-arterial interventions.

Contrast Medium-Induced Acute Kidney Injury.

Contrast medium-induced acute kidney injury (CI-AKI) is a predominant cause of hospital-acquired renal insufficiency. With an increasing number of contrast medium-enhanced radiological procedures being performed in a rapidly increasing ageing population in the Western world, it is imperative that more attention is given to understand the aetiology of CI-AKI to devise novel diagnostic methods and to formulate effective prophylactic and therapeutic regimens to reduce its incidence and its associated morbidity and mortality. This article presents high-yield information on the above-mentioned aspects of CI-AKI, primarily based on results of randomised controlled trials, meta-analyses, systematic reviews and international consensus guidelines.

Reducing contrast-induced acute kidney injury using a regional multicenter quality improvement intervention.

BACKGROUND: Contrast-induced acute kidney injury (CI-AKI) is associated with increased morbidity and mortality after percutaneous coronary interventions and is a patient safety objective of the National Quality Forum. However, no formal quality improvement program to prevent CI-AKI has been conducted. Therefore, we sought to determine whether a 6-year regional multicenter quality improvement intervention could reduce CI-AKI after percutaneous coronary interventions. METHODS AND RESULTS: We conducted a prospective multicenter quality improvement study to prevent CI-AKI (serum creatinine increase ≥0.3 mg/dL within 48 hours or ≥50% during hospitalization) among 21 067 nonemergent patients undergoing percutaneous coronary interventions at 10 hospitals between 2007 and 2012. Six intervention hospitals participated in the quality improvement intervention. Two hospitals with significantly lower baseline rates of CI-AKI, which served as benchmark sites and were used to develop the intervention, and 2 hospitals not receiving the intervention were used as controls. Using time series analysis and multilevel poisson regression clustering to the hospital level, we calculated adjusted risk ratios for CI-AKI comparing the intervention period to baseline. Adjusted rates of CI-AKI were significantly reduced in hospitals receiving the intervention by 21% (risk ratio, 0.79; 95% confidence interval: 0.67-0.93; P=0.005) for all patients and by 28% in patients with baseline estimated glomerular filtration rate <60 mL/min per 1.73 m(2) (risk ratio, 0.72; 95% confidence interval: 0.56-0.91; P=0.007). Benchmark hospitals had no significant changes in CI-AKI. Key qualitative system factors associated with improvement included multidisciplinary teams, limiting contrast volume, standardized fluid orders, intravenous fluid bolus, and patient education about oral hydration. CONCLUSIONS: Simple cost-effective quality improvement interventions can prevent ≤1 in 5 CI-AKI events in patients with undergoing nonemergent percutaneous coronary interventions.

Does safe dosing of iodinated contrast prevent contrast-induced acute kidney injury?

BACKGROUND: Previous work on contrast-induced acute kidney injury (CI-AKI) has identified contrast volume as a risk factor and suggested that there is a maximum allowable contrast dose (MACD) above which the risk of CI-AKI is markedly increased. We hypothesized that there is a relationship between contrast volume and CI-AKI and that there might be reason to track incremental contrast volumes above and below the MACD limit. METHODS AND RESULTS: Consecutive patients undergoing percutaneous coronary intervention (PCI) were prospectively enrolled from 2000 to 2008 (n=10 065). Patients on dialysis before PCI were excluded (n=155). MACD was defined as (5 mL x body weight [kg])/baseline serum creatinine [mg/dL]) and divided into categories in which 1.0 reflects the MACD limit: < or =MACD ratios (<0.5, 0.5 to 0.75, and 0.75 to 1.0) and >MACD (1.0 to 1.5, 1.5 to 2.0, and >2.0). CI-AKI was defined as a > or =0.3 (mg/dL) or > or =50% increase in serum creatinine from baseline or new dialysis. Multivariable regression was conducted to evaluate the effect of exceeding the MACD on CI-AKI. Twenty percent of patients exceeded the MACD. Risk-adjusted CI-AKI increased by an average of 45% for each category exceeding the MACD (odds ratio, 1.45; 95% confidence interval, 1.29 to 1.62) Adjusted odds ratios for each category exceeding the MACD were 1.60 (95% confidence interval, 1.29 to 1.97), 2.02 (95% confidence interval, 1.45 to 2.81), and 2.94 (95% confidence interval, 1.93 to 4.48). CI-AKI for contrast dose

Creatinine increases after intravenous contrast administration: incidence and impact.

OBJECTIVE: The incidence of creatinine increases after intravenous contrast (postcontrast creatinine increases, PCCI) is controversial, ranging from 0% to >25%. We sought to determine what factors influenced these divergent estimates of PCCI incidence. Where possible, the association of PCCI with long-term adverse outcomes was also studied. MATERIALS AND METHODS: Both observational studies and prospective randomized trials were reviewed. Definitions of clinically significant PCCI, incidence of PCCI, and its association with baseline kidney function, the setting in which intravenous contrast was administered, and the short- and long-term consequences of PCCI were extracted. RESULTS: Baseline renal function impairment and inpatient versus outpatient status are the major risk factors for PCCI. PCCI is possibly associated with clinically significant short- and long-term adverse events. CONCLUSIONS: PCCI occurs despite a number of potential confounding issues. The incidence is increased as kidney function at baseline is diminished and for inpatients. There is limited data on long-term outcomes following PCCI in this setting.

Contrast-induced nephropathy and long-term adverse events: cause and effect?

BACKGROUND AND OBJECTIVES: The relationship of contrast-induced nephropathy (CIN) to long-term adverse events (AEs) is controversial. Although an association with AEs has been previously reported, it is unclear whether CIN is causally related to these AEs. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We obtained long-term (> or =1 yr) follow-up on 294 patients who participated in a randomized, double-blind comparison of two prevention strategies for CIN (iopamidol versus iodixanol). A difference in the incidence of AEs between patients who had developed CIN and those who had not was performed using a chi(2) test and Poisson regression analysis. A similar statistical approach was used for the differences in AEs between those who received iopamidol or iodixanol. Multiple definitions of CIN were used to strengthen and validate the results and conclusions. RESULTS: The rate of long-term AEs was higher in individuals with CIN (all definitions of CIN). After adjustment for baseline comorbidities and risk factors, the adjusted incidence rate ratio for AEs was twice as high in those with CIN. Randomization to iopamidol reduced both the incidence of CIN and AEs. CONCLUSIONS: The parallel decrease in the incidence of CIN and AEs in one arm of this randomized trial supports a causal role for CIN.