ACE inhibitors and angiotensin receptor blockers differentially alter the response to angiotensin II treatment in vasodilatory shock.

BACKGROUND: Angiotensin-converting enzyme inhibitor (ACEi) and angiotensin receptor blockers (ARB) medications are widely prescribed. We sought to assess how pre-admission use of these medications might impact the response to angiotensin-II treatment during vasodilatory shock. METHODS: In a post-hoc subgroup analysis of the randomized, placebo-controlled, Angiotensin Therapy for High Output Shock (ATHOS-3) trial, we compared patients with chronic angiotensin-converting enzyme inhibitor (ACEi) use, and patients with angiotensin receptor blocker (ARB) use, to patients without exposure to either ACEi or ARB. The primary outcome was mean arterial pressure after 1-h of treatment. Additional clinical outcomes included mean arterial pressure and norepinephrine equivalent dose requirements over time, and study-drug dose over time. Biological outcomes included baseline RAS biomarkers (renin, angiotensin-I, angiotensin-II, and angiotensin-I/angiotensin-II ratio), and the change in renin from 0 to 3 h. RESULTS: We included n = 321 patients, of whom, 270 were ACEi and ARB-unexposed, 29 were ACEi-exposed and 22 ARB-exposed. In ACEi/ARB-unexposed patients, angiotensin-treated patients, compared to placebo, had higher hour-1 mean arterial pressure (9.1 mmHg [95% CI 7.6-10.1], p < 0.0001), lower norepinephrine equivalent dose over 48-h (p = 0.0037), and lower study-drug dose over 48-h (p < 0.0001). ACEi-exposed patients treated with angiotensin-II showed similarly higher hour-1 mean arterial pressure compared to ACEi/ARB-unexposed (difference in treatment-effect: - 2.2 mmHg [95% CI - 7.0-2.6], pinteraction = 0.38), but a greater reduction in norepinephrine equivalent dose (pinteraction = 0.0031) and study-drug dose (pinteraction < 0.0001) over 48-h. In contrast, ARB-exposed patients showed an attenuated effect of angiotensin-II on hour-1 mean arterial pressure versus ACEi/ARB-unexposed (difference in treatment-effect: - 6.0 mmHg [95% CI - 11.5 to - 0.6], pinteraction = 0.0299), norepinephrine equivalent dose (pinteraction < 0.0001), and study-drug dose (pinteraction = 0.0008). Baseline renin levels and angiotensin-I/angiotensin-II ratios were highest in ACEi-exposed patients. Finally, angiotensin-II treatment reduced hour-3 renin in ACEi/ARB-unexposed and ACEi-exposed patients but not in ARB-exposed patients. CONCLUSIONS: In vasodilatory shock patients, the cardiovascular and biological RAS response to angiotensin-II differed based upon prior exposure to ACEi and ARB medications. ACEi-exposure was associated with increased angiotensin II responsiveness, whereas ARB-exposure was associated with decreased responsiveness. These findings have clinical implications for patient selection and dosage of angiotensin II in vasodilatory shock. Trial Registration ClinicalTrials.Gov Identifier: NCT02338843 (Registered January 14th 2015).

In Vivo Assessment of a Manual Single Lumen Alternating Micro-Batch Hemodiafiltration (mSLAMB) System.

INTRODUCTION: The manual single lumen alternating micro-batch hemodiafiltration (mSLAMB) system is a closed-loop dialysis system designed to provide kidney support in emergency situations (e.g., fluid overload, hyperkalemia, acidemia). If done repeatedly in small batches and at high flow rates, this system was found to achieve clearance levels comparable to traditional renal replacement therapy (RRT). METHODS: Using a porcine model, uremic toxins and exogenous fluorescent tracer concentrations were successfully lowered within just 1 hour of treatment. RESULTS: With a maximal dialysate flow, mSLAMB can achieve decreases in serum potassium concentration of > 0.5 mmol/L/ hr. With the mSLAMB hemodiafiltration system, micro-batch processing was also successful in removing up to 250mL of ultrafiltrate in 8 cycles. CONCLUSION: This process could create a better fluid balance allowing for administering therapeutic fluids such as sodium bicarbonate in the clinic. Electrolyte imbalance and volume overload remain severe life-threatening emergencies in low resource settings, therefore mSLAMB should be explored further due to its modest vascular access requirements, low cost, and ability to be performed without electricity or batteries.

CCL14 Predicts Oliguria and Dialysis Requirement in Patients with Moderate to Severe Acute Kidney Injury.

INTRODUCTION: AKI is a frequent complication of critical illness and portends poor outcome. CCL14 is a validated predictor of persistent severe AKI in critically ill patients. We examined the association of CCL14 with urine output within 48 h. METHODS: In pooled data from 2 studies of critically ill patients with KDIGO stage 2-3 AKI, CCL14 was measured by NEPHROCLEAR™ CCL14 Test on the Astute 140® Meter (low, intermediate, and high categories [1.3 and 13 ng/mL]). Average hourly urine output over 48 h, stage 3 AKI per urine output criterion on day 2, and composite of dialysis or death within 7 days were examined using multivariable mixed and logistic regression models. RESULTS: Of the 497 subjects with median age of 65 (56-74) years, 49% (242/497) were on diuretics. CCL14 concentration was low in 219 (44%), intermediate in 217 (44%), and high in 61 (12%) patients. In mixed regression analysis, hourly urine output over time was different within each CCL14 risk category based on diuretic use due to significant three-way interaction (p < 0.001). In logistic regression analysis, CCL14 risk category was independently associated with low urine output on day 2 per KDIGO stage 3 (adjusted for diuretic use and baseline clinical variables), and composite of dialysis or death within 7 days (adjusted for urine output within 48 h of CCL14 measurement). CONCLUSIONS: CCL14 measured in patients with moderate to severe AKI is associated with urine output trajectory within 48 h, oliguria on day 2, and dialysis within 7 days.

Predicting the Development of Renal Replacement Therapy Indications by Combining the Furosemide Stress Test and Chemokine (C-C Motif) Ligand 14 in a Cohort of Postsurgical Patients.

OBJECTIVES: Optimal timing of renal replacement therapy (RRT) initiation in severe acute kidney injury (AKI) remains controversial. Initiation of treatment early in the course of AKI may lead to some patients undergoing unnecessary RRT, whereas delayed treatment is associated with increased mortality. This study aims to investigate whether the combination of the furosemide stress test (FST) and AKI-associated biomarkers can predict the development of indications for RRT. DESIGN: Single-center, prospective, observational study. SETTING: University Hospital of Muenster, Germany. PATIENTS: Critically ill, postoperative patients with moderate AKI (Kidney Disease: Improving Global Outcomes stage 2) and risk factors for further progression (vasopressors and/or mechanical ventilation) receiving an FST. INTERVENTIONS: Sample collection and measurement of different biomarkers (chemokine [C-C motif] ligand 14 [CCL14], neutrophil gelatinase-associated lipocalin, dipeptidyl peptidase 3). MEASUREMENT AND MAIN RESULTS: The primary endpoint was the development of greater than or equal to one predefined RRT indications (hyperkalemia [≥ 6 mmol/L], diuretic-resistant hypervolemia, high urea serum levels [≥ 150 mg/dL], severe metabolic acidosis [pH ≤ 7.15], oliguria [urinary output < 200 mL/12 hr], or anuria). Two hundred eight patients were available for the primary analysis with 108 having a negative FST (urine output < 200 mL in 2 hr following FST). Ninety-eight patients (47%) met the primary endpoint, 82% in the FST negative cohort. At the time of inclusion, the combination of a negative FST test and high urinary CCL14 levels had a significantly higher predictive value for the primary endpoint with an area under the receiver operating characteristic curve (AUC) of 0.87 (95% CI, 0.82-0.92) compared with FST or CCL14 alone (AUC, 0.79; 95% CI, 0.74-0.85 and AUC, 0.83; 95% CI, 0.77-0.89; p < 0.001, respectively). Other biomarkers showed lower AUCs. CONCLUSIONS: The combination of the FST with the renal biomarker CCL14 predicts the development of indications for RRT.

Rationale for sequential extracorporeal therapy (SET) in sepsis.

Sepsis and septic shock remain drivers for morbidity and mortality in critical illness. The clinical picture of patients presenting with these syndromes evolves rapidly and may be characterised by: (a) microbial host invasion, (b) establishment of an infection focus, (c) opsonisation of bacterial products (e.g. lipopolysaccharide), (d) recognition of pathogens resulting in an immune response, (e) cellular and humoral effects of circulating pathogen and pathogen products, (f) immunodysregulation and endocrine effects of cytokines, (g) endothelial and organ damage, and (h) organ crosstalk and multiple organ dysfunction. Each step may be a potential target for a specific therapeutic approach. At various stages, extracorporeal therapies may target circulating molecules for removal. In sequence, we could consider: (a) pathogen removal from the circulation with affinity binders and cartridges (specific), (b) circulating endotoxin removal by haemoperfusion with polymyxin B adsorbers (specific), (c) cytokine removal by haemoperfusion with sorbent cartridges or adsorbing membranes (non-specific), (d) extracorporeal organ support with different techniques for respiratory and cardiac support (CO2 removal or extracorporeal membrane oxygenation), and renal support (haemofiltration, haemodialysis, or ultrafiltration). The sequence of events and the use of different techniques at different points for specific targets will likely require trials with endpoints other than mortality. Instead, the primary objectives should be to achieve the desired action by using extracorporeal therapy at a specific point.

External validation of the modified sepsis renal angina index for prediction of severe acute kidney injury in children with septic shock.

BACKGROUND: Acute kidney injury (AKI) occurs commonly in pediatric septic shock and increases morbidity and mortality. Early identification of high-risk patients can facilitate targeted intervention to improve outcomes. We previously modified the renal angina index (RAI), a validated AKI prediction tool, to improve specificity in this population (sRAI). Here, we prospectively assess sRAI performance in a separate cohort. METHODS: A secondary analysis of a prospective, multicenter, observational study of children with septic shock admitted to the pediatric intensive care unit from 1/2019 to 12/2022. The primary outcome was severe AKI (≥ KDIGO Stage 2) on Day 3 (D3 severe AKI), and we compared predictive performance of the sRAI (calculated on Day 1) to the original RAI and serum creatinine elevation above baseline (D1 SCr > Baseline +). Original renal angina fulfillment (RAI +) was defined as RAI ≥ 8; sepsis renal angina fulfillment (sRAI +) was defined as RAI ≥ 20 or RAI 8 to < 20 with platelets < 150 × 103/µL. RESULTS: Among 363 patients, 79 (22%) developed D3 severe AKI. One hundred forty (39%) were sRAI + , 195 (54%) RAI + , and 253 (70%) D1 SCr > Baseline + . Compared to sRAI-, sRAI + had higher risk of D3 severe AKI (RR 8.9, 95%CI 5-16, p < 0.001), kidney replacement therapy (KRT) (RR 18, 95%CI 6.6-49, p < 0.001), and mortality (RR 2.5, 95%CI 1.2-5.5, p = 0.013). sRAI predicted D3 severe AKI with an AUROC of 0.86 (95%CI 0.82-0.90), with greater specificity (74%) than D1 SCr > Baseline (36%) and RAI + (58%). On multivariable regression, sRAI + retained associations with D3 severe AKI (aOR 4.5, 95%CI 2.0-10.2, p < 0.001) and need for KRT (aOR 5.6, 95%CI 1.5-21.5, p = 0.01). CONCLUSIONS: Prediction of severe AKI in pediatric septic shock is important to improve outcomes, allocate resources, and inform enrollment in clinical trials examining potential disease-modifying therapies. The sRAI affords more accurate and specific prediction than context-free SCr elevation or the original RAI in this population.

Anticoagulation practices for continuous renal replacement therapy: a survey of physicians from the United States.

BACKGROUND: During continuous renal replacement therapy (CRRT), anticoagulants are recommended for patients at low risk of bleeding and not already receiving systemic anticoagulants. Current anticoagulants used in CRRT in the US are systemic heparins or regional citrate. To better understand use of anticoagulants for CRRT in the US, we surveyed nephrologists and critical care medicine (CCM) specialists. METHODS: The survey contained 30 questions. Respondents were board certified and worked in intensive care units of academic medical centers or community hospitals. RESULTS: 150 physicians (70 nephrologists and 80 CCM) completed the survey. Mean number of CRRT machines in use increased ∼30% from the pre-pandemic era to 2022. Unfractionated heparin was the most used anticoagulant (43% of estimated patients) followed by citrate (28%). Respondents reported 29% of patients received no anticoagulant. Risk of hypocalcemia (52%) and citrate safety (42%) were the predominant reasons given for using no anticoagulant instead of citrate in heparin-intolerant patients. 84% said filter clogging was a problem when no anticoagulant was used, and almost 25% said increased transfusions were necessary. Respondents using heparin (n = 131) considered it inexpensive and easily obtainable, although of moderate safety, citing concerns of heparin-induced thrombocytopenia and bleeding. Anticoagulant citrate dextrose solution was the most used citrate. Respondents estimated that 37% of patients receiving citrate develop hypocalcemia and 17% citrate lock. CONCLUSIONS: Given the increased use of CRRT and the lack of approved, safe, and effective anticoagulant choices for CRRT in the US, effective use of current and other anticoagulant options needs to be evaluated.

Permissive azotemia during acute kidney injury enables more rapid renal recovery and less renal fibrosis: a hypothesis and clinical development plan.

Preclinical models of acute kidney injury (AKI) consistently demonstrate that a uremic milieu enhances renal recovery and decreases kidney fibrosis. Similarly, significant decreases in monocyte/macrophage infiltration, complement levels, and other markers of inflammation in the injured kidney are observed across multiple studies and species. In essence, decreased renal clearance has the surprising and counterintuitive effect of being an effective treatment for AKI. In this Perspective, the author suggests a hypothesis describing why the uremic milieu is kidney protective and proposes a clinical trial of 'permissive azotemia' to improve renal recovery and long-term renal outcomes in critically ill patients with severe AKI.

The Association Between Angiotensin II and Renin Kinetics in Patients After Cardiac Surgery.

BACKGROUND: Hyperreninemia after cardiac surgery is associated with cardiovascular instability. Angiotensin II (AT-II) could potentially attenuate hyperreninemia while maintaining target blood pressure. This study assesses the association between AT-II usage and renin levels in cardiac surgery patients with postoperative hyperreninemia and vasoplegia. METHODS: Between September 2020 and March 2021, we retrospectively identified 40 cardiac surgery patients with high Δ-renin levels (4 hours after cardiopulmonary bypass [CPB] minus preoperative levels) (defined as higher than 3.7 µU/mL) and vasopressor use who received a vasopressor therapy with either AT-II or continued norepinephrine alone. The primary outcome was the renin plasma level at 12 hours after surgery, adjusted by the renin plasma level at 4 hours after surgery. RESULTS: Overall, the median renin plasma concentration increased from a baseline with median of 44.3 µU/mL (Q1-Q3, 14.6-155.5) to 188.6 µU/mL (Q1-Q3, 29.8-379.0) 4 hours after CPB. High Δ-renin (difference between postoperation and preoperation) patients (higher than 3.7 µU/mL) were then treated with norepinephrine alone (median dose of 3.25 mg [Q1-Q3, 1.00-4.75]) or with additional AT-II (norepinephrine dose: 1.33 mg [Q1-Q3, 0.78-2.04]; AT-II dose: 0.34 mg [Q1-Q3, 0.29-0.78]). At 12 hours after surgery, AT-II patients had lower renin levels than standard of care patients (71.7 µU/mL [Q1-Q3, 21.9-211.4] vs 130.6 µU/mL [Q1-Q3, 62.9-317.0]; P = .034 adjusting for the renin plasma level at 4 hours after surgery). CONCLUSIONS: In cardiac surgery patients with hypotonia and postoperative high Δ-renin levels, AT-II was associated with reduced renin plasma levels for at 12 hours and significantly decreased norepinephrine use, while norepinephrine alone was associated with increased renin levels. Further studies of AT-II in cardiac surgery appear justified.

Kinetic Changes of Plasma Renin Concentrations Predict Acute Kidney Injury in Cardiac Surgery Patients.

Rationale: The renin-angiotensin-aldosterone system is a major pathway in regulating blood pressure, glomerular filtration, and fluid homeostasis. During inflammatory diseases, generation of angiotensin II might be disturbed, leading to increased renin concentrations. Cardiac surgery and the use of cardiopulmonary bypass both induce inflammatory response and cardiovascular instability, which can contribute to acute kidney injury (AKI).Objectives: To investigate whether renin concentrations are associated with hypotension and AKI.Methods: This is a single-center, prospective, observational study among patients undergoing cardiac surgery.Measurements and Main Results: The primary endpoint was the occurrence of AKI within 72 hours after cardiac surgery. A total of 197 patients were available for the primary analysis. The median renin serum concentration was 40.2 µU/ml (quartile 1 [Q1]-Q3, 9.3-144.4) at baseline and 51.3 µU/ml (Q1-Q3, 19.1-167.0) 4 hours after cardiac surgery, whereas the difference between postoperation and preoperation concentrations (Δ-renin) was 3.7 µU/ml (Q1-Q3, -22.7 to 50.9). Patients with an elevated Δ-renin developed an AKI significantly more often (43% vs. 12.2%; P < 0.001). High Δ-renin after cardiac surgery was associated with a significantly lower mean arterial pressure, longer time on vasopressors, and longer length of ICU and hospital stay. The area under the curve (AUC) of Δ-renin for the prediction of AKI (AUC, 0.817; 95% confidence interval, 0.747-0.887) was significantly greater compared with the AUC of the postoperative renin concentrations (AUC, 0.702; 95% CI, 0.610-0.793; P = 0.007).Conclusions: Elevated renin concentrations were associated with cardiovascular instability and increased AKI after cardiac surgery. Elevated renin concentrations could be used to identify high-risk patients for cardiovascular instability and AKI who would benefit from timely intervention that could improve their outcomes.

Use of Biomarkers to Identify Acute Kidney Injury to Help Detect Sepsis in Patients With Infection.

OBJECTIVES: Although early recognition of sepsis is vital to improving outcomes, the diagnosis may be missed or delayed in many patients. Acute kidney injury is one of the most common organ failures in patients with sepsis but may not be apparent on presentation. Novel biomarkers for acute kidney injury might improve organ failure recognition and facilitate earlier sepsis care. DESIGN: Retrospective, international, Sapphire study. SETTING: Academic Medical Center. PATIENTS: Adults admitted to the ICU without evidence of acute kidney injury at time of enrollment. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We stratified patients enrolled in the Sapphire study into three groups-those with a clinical diagnosis of sepsis (n = 216), those with infection without sepsis (n = 120), and those without infection (n = 387) at enrollment. We then examined 30-day mortality stratified by acute kidney injury within each group. Finally, we determined the operating characteristics for kidney stress markers (tissue inhibitor of metalloproteinases-2) × (insulin-like growth factor binding protein 7) for prediction of acute kidney injury as a sepsis-defining organ failure in patients with infection without a clinical diagnosis of sepsis at enrollment. Combining all groups, 30-day mortality was 23% for patients who developed stage 2-3 acute kidney injury within the first 3 days compared with 14% without stage 2-3 acute kidney injury. However, this difference was greatest in the infection without sepsis group (34% vs 11%; odds ratio, 4.09; 95% CI, 1.53-11.12; p = 0.005). Using a (tissue inhibitor of metalloproteinases-2) × (insulin-like growth factor binding protein 7) cutoff of 2.0 units, 14 patients (11.7%), in the infection/no sepsis group, tested positive of which 10 (71.4%) developed stage 2-3 acute kidney injury. The positive test result occurred a median of 19 hours (interquartile range, 0.8-34.0 hr) before acute kidney injury manifested by serum creatinine or urine output. Similar results were obtained using a cutoff of 1.0 for any stage of acute kidney injury. CONCLUSIONS: Use of the urinary (tissue inhibitor of metalloproteinases-2) × (insulin-like growth factor binding protein 7) test could identify acute kidney injury in patients with infection, possibly helping to detect sepsis, nearly a day before acute kidney injury is apparent by clinical criteria.

External validation of urinary C-C motif chemokine ligand 14 (CCL14) for prediction of persistent acute kidney injury.

BACKGROUND: Persistent acute kidney injury (AKI) portends worse clinical outcomes and remains a therapeutic challenge for clinicians. A recent study found that urinary C-C motif chemokine ligand 14 (CCL14) can predict the development of persistent AKI. We aimed to externally validate urinary CCL14 for the prediction of persistent AKI in critically ill patients. METHODS: This was a secondary analysis of the prospective multi-center SAPPHIRE study. We evaluated critically ill patients with cardiac and/or respiratory dysfunction who developed Kidney Disease: Improving Global Outcomes (KDIGO) stage 2-3 AKI within one week of enrollment. The main exposure was the urinary concentration of CCL14 measured at the onset of AKI stage 2-3. The primary endpoint was the development of persistent severe AKI, defined as ≥ 72 h of KDIGO stage 3 AKI or death or renal-replacement therapy (RRT) prior to 72 h. The secondary endpoint was a composite of RRT and/or death by 90 days. We used receiver operating characteristic (ROC) curve analysis to assess discriminative ability of urinary CCL14 for the development of persistent severe AKI and multivariate analysis to compare tertiles of urinary CCL14 and outcomes. RESULTS: We included 195 patients who developed KDIGO stage 2-3 AKI. Of these, 28 (14%) developed persistent severe AKI, of whom 15 had AKI ≥ 72 h, 12 received RRT and 1 died prior to ≥ 72 h of KDIGO stage 3 AKI. Persistent severe AKI was associated with chronic kidney disease, diabetes mellitus, higher non-renal APACHE III score, greater fluid balance, vasopressor use, and greater change in baseline serum creatinine. The AUC for urinary CCL14 to predict persistent severe AKI was 0.81 (95% CI, 0.72-0.89). The risk of persistent severe AKI increased with higher values of urinary CCL14. RRT and/or death at 90 days increased within tertiles of urinary CCL14 concentration. CONCLUSIONS: This secondary analysis externally validates urinary CCL14 to predict persistent severe AKI in critically ill patients.

Serial Measurement of Cell-Cycle Arrest Biomarkers [TIMP-2] · [IGFBP7] and Risk for Progression to Death, Dialysis, or Severe Acute Kidney Injury in Patients with Septic Shock.

Rationale: Urinary TIMP-2 (tissue inhibitor of metalloproteinases-2) and IGFBP7 (insulin-like growth factor-binding protein 7) can predict acute kidney injury (AKI) in patients with sepsis.Objectives: To address critical questions about whether biomarkers can inform the response to treatment and whether they might be used to guide therapy, as most sepsis patients present with AKI.Methods: We measured [TIMP-2] · [IGFBP7] before and after a 6-hour resuscitation in 688 patients with septic shock enrolled in the ProCESS (Protocol-based Care for Early Septic Shock) trial. Our primary endpoint was stage 3 AKI, renal replacement therapy, or death within 7 days.Measurements and Main Results: The endpoint was reached in 113 patients (16.4%). In patients with negative [TIMP-2] · [IGFBP7] at baseline, those who became positive (>0.3 U) after resuscitation had three-times higher risk compared with those who remained negative (21.8% vs. 8.5%; P = 0.01; odds ratio [OR], 3.0; 95% confidence interval [CI], 1.31-6.87). Conversely, compared with patients with a positive biomarker at baseline that were still positive at Hour 6, risk was reduced for patients who became negative (23.8% vs. 9.8%; P = 0.01; OR, 2.15; 95% CI, 1.17-3.95). A positive [TIMP-2] · [IGFBP7] after resuscitation was associated with worse outcomes in both patients with and without AKI at that time point. The clinical response to resuscitation, as judged by the Acute Physiology and Chronic Health Evaluation II score, was weakly predictive of the endpoint (area under the curve, 0.68; 95% CI, 0.62-0.73) and improved with addition of [TIMP-2] · [IGFBP7] (0.72; 95% CI, 0.66-0.77; P = 0.03). Different resuscitation protocols did not alter biomarker trajectories, nor did they alter outcomes in biomarker-positive or biomarker-negative patients. However, biomarker trajectories were associated with outcomes.Conclusions: Changes in urinary [TIMP-2] · [IGFBP7] after initial fluid resuscitation identify patients with sepsis who have differing risk for progression of AKI.Clinical trial registered with www.clinicaltrials.gov (NCT00510835).

Renin and Survival in Patients Given Angiotensin II for Catecholamine-Resistant Vasodilatory Shock. A Clinical Trial.

Rationale: Exogenous angiotensin II increases mean arterial pressure in patients with catecholamine-resistant vasodilatory shock (CRVS). We hypothesized that renin concentrations may identify patients most likely to benefit from such therapy.Objectives: To test the kinetic changes in renin concentrations and their prognostic value in patients with CRVS.Methods: We analyzed serum samples from patients enrolled in the ATHOS-3 (Angiotensin II for the Treatment of High-Output Shock) trial for renin, angiotensin I, and angiotensin II concentrations before the start of administration of angiotensin II or placebo and after 3 hours.Measurements and Main Results: Baseline serum renin concentration (normal range, 2.13-58.78 pg/ml) was above the upper limits of normal in 194 of 255 (76%) study patients with a median renin concentration of 172.7 pg/ml (interquartile range [IQR], 60.7 to 440.6 pg/ml), approximately threefold higher than the upper limit of normal. Renin concentrations correlated positively with angiotensin I/II ratios (r = 0.39; P < 0.001). At 3 hours after initiation of angiotensin II therapy, there was a 54.3% reduction (IQR, 37.9% to 66.5% reduction) in renin concentration compared with a 14.1% reduction (IQR, 37.6% reduction to 5.1% increase) with placebo (P < 0.0001). In patients with renin concentrations above the study population median, angiotensin II significantly reduced 28-day mortality to 28 of 55 (50.9%) patients compared with 51 of 73 patients (69.9%) treated with placebo (unstratified hazard ratio, 0.56; 95% confidence interval, 0.35 to 0.88; P = 0.012) (P = 0.048 for the interaction).Conclusions: The serum renin concentration is markedly elevated in CRVS and may identify patients for whom treatment with angiotensin II has a beneficial effect on clinical outcomes.Clinical trial registered with www.clinicaltrials.gov (NCT02338843).

The furosemide stress test: current use and future potential.

Loop diuretics are among the most widely used drugs worldwide and are commonly employed in the management of complications associated with acute kidney injury (AKI), namely volume overload and electrolyte management. The use of loop diuretics in critically ill patients with AKI is paramount to preventing or treating pulmonary edema. The naturetic response to a loop diuretic is based on its unique renal pharmacology. Our review article summarizes the pharmacology of furosemide in the intact nephron and discusses how this response might be altered by the presence of AKI. We discuss the increasing body of literature on the latest clinical utility of furosemide namely, it's challenge test, known as the furosemide stress test which has highlighted a new and novel role for furosemide over the past number of years. This test assists with the identification of AKI subjects at higher risk of AKI progression and the need for renal replacement therapy. The stress test can also predict cessation of continuous renal replacement therapy in patients with established AKI. On the basis of the evidence presented in this review, we propose future potential studies of furosemide in AKI.

Angiotensin II for the Treatment of Vasodilatory Shock.

BACKGROUND: Vasodilatory shock that does not respond to high-dose vasopressors is associated with high mortality. We investigated the effectiveness of angiotensin II for the treatment of patients with this condition. METHODS: We randomly assigned patients with vasodilatory shock who were receiving more than 0.2 µg of norepinephrine per kilogram of body weight per minute or the equivalent dose of another vasopressor to receive infusions of either angiotensin II or placebo. The primary end point was a response with respect to mean arterial pressure at hour 3 after the start of infusion, with response defined as an increase from baseline of at least 10 mm Hg or an increase to at least 75 mm Hg, without an increase in the dose of background vasopressors. RESULTS: A total of 344 patients were assigned to one of the two regimens; 321 received a study intervention (163 received angiotensin II, and 158 received placebo) and were included in the analysis. The primary end point was reached by more patients in the angiotensin II group (114 of 163 patients, 69.9%) than in the placebo group (37 of 158 patients, 23.4%) (odds ratio, 7.95; 95% confidence interval [CI], 4.76 to 13.3; P<0.001). At 48 hours, the mean improvement in the cardiovascular Sequential Organ Failure Assessment (SOFA) score (scores range from 0 to 4, with higher scores indicating more severe dysfunction) was greater in the angiotensin II group than in the placebo group (-1.75 vs. -1.28, P=0.01). Serious adverse events were reported in 60.7% of the patients in the angiotensin II group and in 67.1% in the placebo group. Death by day 28 occurred in 75 of 163 patients (46%) in the angiotensin II group and in 85 of 158 patients (54%) in the placebo group (hazard ratio, 0.78; 95% CI, 0.57 to 1.07; P=0.12). CONCLUSIONS: Angiotensin II effectively increased blood pressure in patients with vasodilatory shock that did not respond to high doses of conventional vasopressors. (Funded by La Jolla Pharmaceutical Company; ATHOS-3 ClinicalTrials.gov number, NCT02338843 .).

Nephrologist Follow-Up Care of Patients With Acute Kidney Disease Improves Outcomes: Taiwan Experience.

OBJECTIVES: Acute kidney injury (AKI) and acute kidney disease (AKD) are a continuum on a disease spectrum and frequently progress to chronic kidney disease. Benefits of nephrologist subspecialty care during the AKD period after AKI are uncertain. METHODS: Patients with AKI requiring dialysis who subsequently became dialysis independent and survived for at least 90 days, defined as the AKD period, were identified from the Taiwanese population's health insurance database. Cox proportional hazard models using death as the competing risk before and after propensity-score matching were applied to evaluate various endpoints. RESULTS: Among a total of 20 260 patients with AKI requiring dialysis who became dialysis independent, only 7550 (37.3%) patients were followed up with by a nephrologist (F/Unephrol group) during the AKD period. During a mean 4.04 ± 3.56 years of follow-up, the patients in the F/Unephrol group were more often administered statin, antihypertensives, angiotensin converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB), diuretics, antiplatelet agents, and antidiabetic agents. The patients in the F/Unephrol group had a lower mortality rate (hazard ratio [HR] = 0.87, P < .001) and were less likely to have major adverse cardiovascular events (MACE) (subdistribution HR [sHR] = 0.85, P < .001), congestive heart failure (CHF) (sHR = 0.81, P < .001), and severe sepsis (sHR = 0.88, P = .008) according to the Cox proportional model after adjusting for mortality as a competing risk. During the AKD period, an increase in the frequency of nephrology visits was associated with improved outcomes. CONCLUSIONS: In this population-based cohort, even after weaning off acute dialysis, only a minority of patients visited a nephrologist during the AKD period. We showed that nephrology follow-up is associated with a decrease in MACE, CHF exacerbations, and sepsis, as well as lower mortality; thus it may improve outcomes in patients with AKD.

Angiotensin I and angiotensin II concentrations and their ratio in catecholamine-resistant vasodilatory shock.

BACKGROUND: In patients with vasodilatory shock, plasma concentrations of angiotensin I (ANG I) and II (ANG II) and their ratio may reflect differences in the response to severe vasodilation, provide novel insights into its biology, and predict clinical outcomes. The objective of these protocol prespecified and subsequent post hoc analyses was to assess the epidemiology and outcome associations of plasma ANG I and ANG II levels and their ratio in patients with catecholamine-resistant vasodilatory shock (CRVS) enrolled in the Angiotensin II for the Treatment of High-Output Shock (ATHOS-3) study. METHODS: We measured ANG I and ANG II levels at baseline, calculated their ratio, and compared these results to values from healthy volunteers (controls). We dichotomized patients according to the median ANG I/II ratio (1.63) and compared demographics, clinical characteristics, and clinical outcomes. We constructed a Cox proportional hazards model to test the independent association of ANG I, ANG II, and their ratio with clinical outcomes. RESULTS: Median baseline ANG I level (253 pg/mL [interquartile range (IQR) 72.30-676.00 pg/mL] vs 42 pg/mL [IQR 30.46-87.34 pg/mL] in controls; P <  0.0001) and median ANG I/II ratio (1.63 [IQR 0.98-5.25] vs 0.4 [IQR 0.28-0.64] in controls; P <  0.0001) were elevated, whereas median ANG II levels were similar (84 pg/mL [IQR 23.85-299.50 pg/mL] vs 97 pg/mL [IQR 35.27-181.01 pg/mL] in controls; P = 0.9895). At baseline, patients with a ratio above the median (≥1.63) had higher ANG I levels (P <  0.0001), lower ANG II levels (P <  0.0001), higher albumin concentrations (P = 0.007), and greater incidence of recent (within 1 week) exposure to angiotensin-converting enzyme inhibitors (P <  0.00001), and they received a higher norepinephrine-equivalent dose (P = 0.003). In the placebo group, a baseline ANG I/II ratio <1.63 was associated with improved survival (hazard ratio 0.56; 95% confidence interval 0.36-0.88; P = 0.01) on unadjusted analyses. CONCLUSIONS: Patients with CRVS have elevated ANG I levels and ANG I/II ratios compared with healthy controls. In such patients, a high ANG I/II ratio is associated with greater norepinephrine requirements and is an independent predictor of mortality, thus providing a biological rationale for interventions aimed at its correction. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT02338843. Registered 14 January 2015.

Furosemide stress test and interstitial fibrosis in kidney biopsies in chronic kidney disease.

BACKGROUND: Interstitial fibrosis (IF) on kidney biopsy is one of the most potent risk factors for kidney disease progression. The furosemide stress test (FST) is a validated tool that predicts the severity of acute kidney injury (especially at 2 h) in critically ill patients. Since furosemide is secreted through the kidney tubules, the response to FST represents the tubular secretory capacity. To our knowledge there is no data on the correlation between functional tubular capacity assessed by the FST with IF on kidney biopsies from patients with chronic kidney disease (CKD). The aim of this study was to determine the association between urine output (UO), Furosemide Excreted Mass (FEM) and IF on kidney biopsies after a FST. METHODS: This study included 84 patients who underwent kidney biopsy for clinical indications and a FST. The percentage of fibrosis was determined by morphometry technique and reviewed by a nephropathologist. All patients underwent a FST prior to the biopsy. Urine volume and urinary sodium were measured in addition to urine concentrations of furosemide at different times (2, 4 and 6 h). We used an established equation to determine the FEM. Values were expressed as mean, standard deviation or percentage and Pearson Correlation. RESULTS: The mean age of the participants was 38 years and 44% were male. The prevalence of diabetes mellitus, hypertension and diuretic use was significantly higher with more advanced degree of fibrosis. Nephrotic syndrome and acute kidney graft dysfunction were the most frequent indications for biopsy. eGFR was inversely related to the degree of fibrosis. Subjects with the highest degree of fibrosis (grade 3) showed a significant lower UO at first hour of the FST when compared to lower degrees of fibrosis (p = 0.015). Likewise, the total UO and the FEM was progressively lower with higher degrees of fibrosis. An inversely linear correlation between FEM and the degree of fibrosis (r = - 0.245, p = 0.02) was observed. CONCLUSIONS: Our findings indicate that interstitial fibrosis correlates with total urine output and FEM. Further studies are needed to determine if UO and FST could be a non-invasive tool to evaluate interstitial fibrosis. TRIAL REGISTRATION: ClinicalTrials.gov NCT02417883.

Use of Cell Cycle Arrest Biomarkers in Conjunction With Classical Markers of Acute Kidney Injury.

OBJECTIVES: Decreased urine output and/or increased serum creatinine may herald the development of acute kidney injury or reflect normal physiology. In this secondary analysis of the Sapphire study, we examined biomarkers of cell cycle arrest in the settings of oliguria and/or azotemia to improve risk assessment when used with conventional indices in predicting severe acute kidney injury (Kidney Disease: Improving Global Outcomes 3 defined by the need for renal replacement therapy or changes in urine output, serum creatinine or both) or death. DESIGN: Prospective, international, Sapphire study. SETTING: Academic Medical Center. PATIENTS: Patients without acute kidney injury Kidney Disease: Improving Global Outcomes stage 2 or 3. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary endpoint being development of severe acute kidney injury or death within 1 week. Secondary analysis examined the relationship between tissue inhibitor of metalloproteinases-2 ([TIMP-2]) and insulin growth factor binding protein 7 ([IGFBP7]) and 9-month death or dialysis conditioned on progression to stage 2-3 acute kidney injury within 1 week. Seventy-nine patients reached the primary endpoint and were more likely to be surgical, with higher nonrenal Acute Physiology and Chronic Health Evaluation III scores and more chronic kidney disease. Stage 1 urine output, serum creatinine, and urinary [TIMP-2]•[IGFBP7] greater than 2.0 were all predictive of progression to the primary endpoint independent from nonrenal Acute Physiology and Chronic Health Evaluation III score. Combinations of predictors increased the hazard ratios considerably (from 2.17 to 4.14 to 10.05, respectively). In the presence of acute kidney injury (stage 1), [TIMP-2]•[IGFBP7] greater than 2.0 leads to an increased risk of death or dialysis at 9 months even in the absence of progression of acute kidney injury (stage 2-3) within 7 days. CONCLUSIONS: Cell cycle arrest biomarkers, TIMP-2 and IGFBP7, improve risk stratification for severe outcomes in patients with stage 1 acute kidney injury by urine output, serum creatinine or both, with risk increasing with each acute kidney injury indicator. Longer term outcomes demonstrate that the associated risks of a [TIMP-2]•[IGFBP7] greater than 2.0 is equivalent to acute kidney injury progression even where no progression from stage 1 acute kidney injury is observed.