Combined biomarker analysis for risk of acute kidney injury in patients with ST-segment elevation myocardial infarction

BACKGROUND

Acute kidney injury (AKI) complicating ST-segment elevation myocardial infarction (STEMI) increases subsequent morbidity and mortality. We combined the biomarkers of heart failure (HF; B-type natriuretic peptide [BNP] and soluble ST2 [sST2]) and renal injury (NGAL [neutrophil gelatinase-associated lipocalin] and cystatin C) in predicting the development of AKI in patients with STEMI undergoing primary percutaneous coronary intervention (PCI).

METHODS AND RESULTS

From March 2010 to September 2013, 189 STEMI patients were sequentially enrolled and serum samples were collected at presentation for BNP, sST2, NGAL and cystatin C analysis. 37 patients (19.6%) developed AKI of varying severity within 48 hours of presentation. Univariate analysis showed age, Killip class ≥2, hypertension, white blood cell counts, hemoglobin, estimated glomerular filtration rate, blood urea nitrogen, creatinine, and all the four biomarkers were predictive of AKI. Serum levels of the biomarkers were correlated with risk of AKI and the Acute Kidney Injury Network (AKIN) stage and all significantly discriminated AKI (area under the receiver operating characteristic [ROC] curve: BNP: 0.86, sST2: 0.74, NGAL: 0.75, cystatin C: 0.73; all P < 0.05). Elevation of ≥2 of the biomarkers higher than the cutoff values derived from the ROC analysis improved AKI risk stratification, regardless of the creatine level (creatinine < 1.24 mg/dL: odds ratio [OR] 11.25, 95% confidence interval [CI] 1.63-77.92, P = 0.014; creatinine ≥ 1.24: OR 15.0, 95% CI 1.23-183.6, P = 0.034).

CONCLUSIONS

In this study of STEMI patients undergoing primary PCI, the biomarkers of heart failure (BNP and sST2) and renal injury (NGAL and cystatin C) at presentation were predictive of AKI. High serum levels of the biomarkers were associated with an elevated risk and more advanced stage of AKI. Regardless of the creatinine level, elevation of ≥2 of the biomarkers higher than the cutoff values indicated a further rise in AKI risk. Combined biomarker approach may assist in risk stratification of AKI in patients with STEMI.

Oxidative stress: dual pathway induction in cardiorenal syndrome type 1 pathogenesis

Cardiorenal Syndrome Type 1 (Type 1) is a specific condition which is characterized by a rapid worsening of cardiac function leading to acute kidney injury (AKI). Even though its pathophysiology is complex and not still completely understood, oxidative stress seems to play a pivotal role. In this study, we examined the putative role of oxidative stress in the pathogenesis of CRS Type 1. Twenty-three patients with acute heart failure (AHF) were included in the study. Subsequently, 11 patients who developed AKI due to AHF were classified as CRS Type 1. Quantitative determinations for IL-6, myeloperoxidase (MPO), nitric oxide (NO), copper/zinc superoxide dismutase (Cu/ZnSOD), and endogenous peroxidase activity (EPA) were performed. CRS Type 1 patients displayed significant augmentation in circulating ROS and RNS, as well as expression of IL-6. Quantitative analysis of all oxidative stress markers showed significantly lower oxidative stress levels in controls and AHF compared to CRS Type 1 patients (P < 0.05). This pilot study demonstrates the significantly heightened presence of dual oxidative stress pathway induction in CRS Type 1 compared to AHF patients. Our findings indicate that oxidative stress is a potential therapeutic target, as it promotes inflammation by ROS/RNS-linked pathogenesis.

Novel markers and therapies for patients with acute heart failure and renal dysfunction

BACKGROUND

Acute kidney injury complicates decompensated heart failure in ∼33% of cases and is associated with morbidity and mortality; thus, we sought to systematically review this topic in order to summarize novel diagnostic and therapeutic approaches.

METHODS

Structured PubMed searches on these topics were conducted in February 2014 and relevant literature was identified. The PubMed search identified a total of 192 articles that were individually screened for inclusion in this analysis, and 58 were included.

RESULTS

Acute kidney injury, defined by substantial increases in serum creatinine, is associated consistently with prolonged length of stay, rehospitalization, and mortality. Biomarker studies suggested that natriuretic peptides are prognostic for shorter- and longer-term mortality. Novel proteins indicating kidney damage and albumin in the urine are associated with acute kidney injury. The most promising acute pharmacologic treatment appears to be serelaxin, which has been shown to improve acute heart failure symptoms, hemodynamic parameters, and renal function.

CONCLUSIONS

The presence of acute kidney injury results in worse clinical outcomes for patients with acute heart failure. Novel biomarkers and therapies hold the promise of improving both cardiac and renal outcomes in these patients.

Identification and predicting short-term prognosis of early cardiorenal syndrome type 1: KDIGO is superior to RIFLE or AKIN

Objective

Acute kidney injury (AKI) in patients hospitalized for acute heart failure (AHF) is usually type 1 of the cardiorenal syndrome (CRS) and has been associated with increased morbidity and mortality. Early recognition of AKI is critical. This study was to determine if the new KDIGO criteria (Kidney Disease: Improving Global Outcomes) for identification and short-term prognosis of early CRS type 1 was superior to the previous RIFLE and AKIN criteria.

Methods

The association between AKI diagnosed by KDIGO but not by RIFLE or AKIN and in-hospital mortality was retrospectively evaluated in 1005 Chinese adult patients with AHF between July 2008 and May 2012. AKI was defined as RIFLE, AKIN and KDIGO criteria, respectively. Cox regression was used for multivariate analysis of in-hospital mortality.

Results

Within 7 days on admission, the incidence of CRS type 1 was 38.9% by KDIGO criteria, 34.7% by AKIN, and 32.1% by RIFLE. A total of 110 (10.9%) cases were additional diagnosed by KDIGO criteria but not by RIFLE or AKIN. 89.1% of them were in Stage 1 (AKIN) or Stage Risk (RIFLE). They accounted for 18.4% (25 cases) of the overall death. After adjustment, this proportion remained an independent risk factor for in-hospital mortality [odds ratios (OR)3.24, 95% confidence interval(95%CI) 1.97–5.35]. Kaplan-Meier curve showed AKI patients by RIFLE, AKIN, KDIGO and [K(+)R(−)+K(+)A(−)] had lower hospital survival than non-AKI patients (Log Rank P<0.001).

Conclusion

KDIGO criteria identified significantly more CRS type 1 episodes than RIFLE or AKIN. AKI missed diagnosed by RIFLE or AKIN criteria was an independent risk factor for in-hospital mortality, indicating the new KDIGO criteria was superior to RIFLE and AKIN in predicting short-term outcomes in early CRS type 1.

Impact of onset time of acute kidney injury on outcomes in patients with acute decompensated heart failure

Since acute kidney injury (AKI) is not always related to mortality in patients with acute decompensated heart failure (ADHF), the aim of this study was to focus on onset time of AKI and its clinical importance. A total of 371 ADHF patients were included. The impact of AKI (≥ 0.3 mg/dl or 1.5-fold increase in serum creatinine level within 48 h) with early onset (≤ 4 days from admission) or late onset (≥ 5 days from admission) was assessed. AKI occurred in 99 patients, who were divided into two groups according to the median onset time of AKI: 50 with early onset of AKI and 49 with late onset of AKI. The maximum increase in serum creatinine level from admission was greater in patients with late onset of AKI than in patients with early onset of AKI (p = 0.012). Patients with late onset of AKI had a higher 12-month mortality rate than that in patients with early onset of AKI (log-rank test, p = 0.014). Late onset of AKI was an independent predictor of mortality (hazard ratio: 3.39, 95 % confidence interval: 1.84-6.18, p < 0.001). Late onset of AKI was associated with high blood urea nitrogen level at admission and intravenous administration of dobutamine. In conclusion, late onset of AKI related to high blood urea nitrogen level and intravenous administration of dobutamine, but not early onset of AKI, is linked to high mortality rate. Onset time of AKI may be useful for risk stratification of mortality in ADHF patients developing AKI.

Impact of acute kidney injury on in-hospital outcomes in patients with DeBakey type III acute aortic dissection

The relation between the incidence and severity of acute kidney injury (AKI) and clinical outcomes remains unclear in patients with DeBakey type III acute aortic dissection (AAD). We retrospectively assessed 56 patients admitted to our hospital for type III AAD within 48 hours of the onset of symptoms. The presence of AKI was identified, and its severity was staged on the basis of changes in serum creatinine (SCr) levels within 7 days after admission. We investigated the relations between AKI and clinical presentations, in-hospital complications, and predischarge renal function; AKI was observed in 20 patients (36%). After adjusting for age, gender, and body mass index, the incidence of AKI was associated with a history of hypertension, electrocardiographic ST-T changes, DeBakey type IIIb, and SCr level on admission. Maximum white blood cell count and serum C-reactive protein level were higher in patients with AKI than in those without AKI. AKI was associated with a greater incidence of in-hospital complications (70% vs 39%, p = 0.03) and higher SCr levels at discharge (1.1 [range 1.0 to 2.0] vs 0.9 [range 0.7 to 1.0] mg/dl, p = 0.0001). These associations were more pronounced in patients with relatively severe AKI. Multivariate analysis revealed that SCr level on admission and DeBakey type IIIb with renal artery involvement were major predictors of AKI. In conclusion, renal function on admission and renal artery involvement were significant risk factors for AKI, which was associated with poor outcomes and enhanced inflammatory response during hospitalization in patients with type III AAD.

New scoring system (APACHE-HF) for predicting adverse outcomes in patients with acute heart failure: evaluation of the APACHE II and Modified APACHE II scoring systems

BACKGROUND

No scoring system for assessing acute heart failure (AHF) has been reported.

METHODS AND RESULTS

Data for 824 AHF patients were analyzed. The subjects were divided into an alive (n=750) and a dead group (n=74). We constructed a predictive scoring system based on eight significant APACHE II factors in the alive group [mean arterial pressure (MAP), pulse, sodium, potassium, hematocrit, creatinine, age, and Glasgow Coma Scale (GCS); giving each one point], defined as the APACHE-HF score. The patients were assigned to five groups by the APACHE-HF score [Group 1: point 0 (n=70), Group 2: points 1 and 2 (n=343), Group 3: points 3 and 4 (n=294), Group 4: points 5 and 6 (n=106), and Group 5: points 7 and 8 (n=11)]. A higher optimal balance was observed in the APACHE-HF between sensitivity and specificity [87.8%, 63.9%; area under the curve (AUC)=0.779] at 2.5 points than in the APACHE II (47.3%, 67.3%; AUC=0.558) at 17.5 points. The multivariate Cox regression model identified belonging to Group 5 [hazard ratio (HR): 7.764, 95% confidence interval (CI) 1.586-38.009], Group 4 (HR: 6.903, 95%CI 1.940-24.568) or Group 3 (HR: 5.335, 95%CI 1.582-17.994) to be an independent predictor of 3-year mortality. The Kaplan-Meier curves revealed a poorer prognosis, including all-cause death and HF events (death, readmission-HF), in Group 5 and Group 4 than in the other groups, in Group 3 than in Group 2 or Group 1, and in Group 2 than in Group 1.

CONCLUSIONS

The new scoring system including MAP, pulse, sodium, potassium, hematocrit, creatinine, age, and GCS (APACHE-HF) can be used to predict adverse outcomes of AHF.

Immediate administration of tolvaptan prevents the exacerbation of acute kidney injury and improves the mid-term prognosis of patients with severely decompensated acute heart failure

BACKGROUND

 Tolvaptan, an oral selective vasopressin 2 receptor antagonist that acts on the distal nephrons to cause a loss of electrolyte-free water, is rarely used during the acute phase of acute heart failure (AHF).

METHODS AND RESULTS

 We investigated 183 AHF patients admitted to the intensive care unit and administered tolvaptan (7.5mg) with continuous intravenous furosemide, and then additionally at 12-h intervals until HF was compensated. When intravenous furosemide was changed to peroral use, the administration of tolvaptan was stopped. The patients were assigned to tolvaptan (n=52) or conventional treatment (n=131) groups. The amount of intravenous furosemide was significantly lower (35.4 [16.3-56.0] mg vs. 80.0 [30.4-220.0] mg), the urine volume was significantly higher on days 1 and 2 (3,691 [3,109-4,198] ml and 2,953 [2,128-3,592] ml vs. 2,270 [1,535-3,258] ml and 2,129 [1,407-2,906] ml) and the numbers of patients with worsening-AKI (step-up RIFLE Class to I or F) and Class F were significantly fewer (5.8% and 1.9% vs. 19.1% and 16.0%) in the tolvaptan group than in the conventional group, respectively. One of the specific medications indicated worsening-AKI and in-hospital mortality was tolvaptan (odds ratio [OR] 0.155, 95% confidence interval [CI] 0.037-0.657 and OR 0.191, 95% CI 0.037-0.985). The Kaplan-Meier curves showed that the death rate within 6 months was significantly lower in the tolvaptan group. The same result was found after propensity matching of the data.

CONCLUSIONS

 Early administration of tolvaptan could prevent exacerbation of AKI and improve the prognosis for AHF patients. 

Renal impairment, worsening renal function, and outcome in patients with heart failure: an updated meta-analysis

AIMS

Chronic kidney disease (CKD) and worsening renal function (WRF) have been associated with poor outcome in heart failure (HF).

METHODS AND RESULTS

Articles were identified by literature search of MEDLINE (from inception to 1 July 2012) and Cochrane. We included studies on HF patients and mortality risk with CKD and/or WRF. In a secondary analysis, we selected studies investigating predictors of WRF. We retrieved 57 studies (1,076,104 patients) that investigated CKD and 28 studies (49,890 patients) that investigated WRF. The prevalence of CKD was 32% and associated with all-cause mortality: odds ratio (OR) 2.34, 95% confidence interval (CI) 2.20-2.50, P < 0.001). Worsening renal function was present in 23% and associated with unfavourable outcome (OR 1.81, 95% CI 1.55-2.12, P < 0.001). In multivariate analysis, moderate renal impairment: hazard ratio (HR) 1.59, 95% CI 1.49-1.69, P < 0.001, severe renal impairment, HR 2.17, 95% CI 1.95-2.40, P < 0.001, and WRF, HR 1.95, 95% CI 1.45-2.62, P < 0.001 were all independent predictors of mortality. Across studies, baseline CKD, history of hypertension and diabetes, age, and diuretic use were significant predictors for the occurrence of WRF.

CONCLUSION

Across all subgroups of patients with HF, CKD, and WRF are prevalent and associated with a strongly increased mortality risk, especially CKD. Specific conditions may predict the occurrence of WRF and thereby poor prognosis.

Kidney Disease Improving Global Outcomes or creatinine kinetics criteria in acute kidney injury: a proof of concept study

BACKGROUND

It has been recently mathematically demonstrated that the percentage increase in serum creatinine (SCr) can delay acute kidney injury (AKI) diagnosis in patients with previous chronic kidney disease (CKD). Based on creatinine (Cr) kinetics, it was suggested a new AKI classification using absolute increase in SCr elevation over specified time periods. However, this classification has not been evaluated in clinical studies.

METHODS

A prospective cohort study evaluated myocardial infarction patients during the first 7 days of hospital stay with daily SCr measurements. They were classified using Kidney Disease Improving Global Outcomes (KDIGO) and Cr kinetics systems. Both classifications were compared by net reclassification improvement (NRI) and area under the receiver operator characteristic (AuROC) curve regarding hospital mortality.

RESULTS

A total of 584 patients were included, of which 34.1% had previous CKD. Patients had more AKI by KDIGO than by Cr kinetics criteria (25.7 versus 18.0%, P < 0.001) and 81 patients (13.9%) had different AKI severity classification. Patients with AKI by KDIGO criteria and non-AKI by Cr kinetics had higher hospital mortality rates than patients with non-AKI using both classifications [adjusted mortality odds ratios (ORs): 4.753; 95% confidence interval (CI): 1.119-9.023, P = 0.014]. In patients with previous CKD, NRI analysis was 6.2% favoring Cr kinetics criteria. However, there was no difference using the AuROC curve analysis. In patients with no previous CKD, NRI analysis was 33.0%, favoring KDIGO, and this was in accordance with a better AuROC curve (0.828 versus 0.664, P < 0.05).

CONCLUSIONS

AKI classification proposed by a Cr kinetics model can be superior when diagnosing patients with previous CKD. However, KDIGO had a better performance in patients with no previous CKD.

Cardiorenal syndrome: ultrafiltration therapy for heart failure--trials and tribulations

Heart failure remains the leading cause of hospitalization in older patients and is considered a growing public health problem with a significant financial burden on the health care system. The suboptimal efficacy and safety profile of diuretic-based therapeutic regimens coupled with unsatisfactory results of the studies on novel pharmacologic agents have positioned ultrafiltration on the forefront as an appealing therapeutic option for patients with acute decompensated heart failure (ADHF). In recent years, substantial interest in the use of ultrafiltration has been generated due to the advent of dedicated portable devices and promising results of trials focusing both on mechanistic and clinical aspects of this therapeutic modality. This article briefly reviews the proposed benefits of ultrafiltration therapy in the setting of ADHF and summarizes the major findings of the currently available studies in this field. The results of more recent trials on cardiorenal syndrome that present a counterpoint to previous observations and highlight certain limitations of ultrafiltration therapy are then discussed, followed by identification of major challenges and unanswered questions that could potentially hinder its more widespread use. Future studies are warranted to shed light on less well characterized aspects of ultrafiltration therapy and to further define its role in ADHF and cardiorenal syndrome.

Current and novel renal biomarkers in heart failure

Renal function is the most important predictor of clinical outcome in heart failure (HF). It is therefore essential to have accurate and reliable measurement of renal function and early specific markers of renal impairment in patients with HF. Several renal functional entities exist, including glomerular filtration (GFR), glomerular permeability, tubulointerstitial damage, and endocrine function. Different markers have been studied that can be used to determine changes and the effect of treatment in these entities. In the present review, we summarize current and novel markers that give an assessment of renal function and prognosis in the setting of acute and chronic HF.

Epidemiology of acute kidney injury in the intensive care unit

The incidence of acute kidney injury (AKI) in the intensive care unit (ICU) has increased during the past decade due to increased acuity as well as increased recognition. Early epidemiology studies were confounded by erratic definitions of AKI until recent consensus guidelines (RIFLE and AKIN) standardized its definition. This paper discusses the incidence of AKI in the ICU with focuses on specific patient populations. The overall incidence of AKI in ICU patients ranges from 20% to 50% with lower incidence seen in elective surgical patients and higher incidence in sepsis patients. The incidence of contrast-induced AKI is less (11.5%–19% of all admissions) than seen in the ICU population at large. AKI represents a significant risk factor for mortality and can be associated with mortality greater than 50%.

A Comparison of Traditional and Novel Definitions (RIFLE, AKIN, and KDIGO) of Acute Kidney Injury for the Prediction of Outcomes in Acute Decompensated Heart Failure

AIMS

To determine if newer criteria for diagnosing and staging acute kidney injury (AKI) during heart failure (HF) admission are more predictive of clinical outcomes at 30 days and 1 year than the traditional worsening renal function (WRF) definition.

METHODS

We analyzed prospectively collected clinical data on 637 HF admissions with 30-day and 1-year follow-up. The incidence, stages, and outcomes of AKI were determined using the following four definitions: KDIGO, RIFLE, AKIN, and WRF (serum creatinine rise ≥0.3 mg/dl). Receiver operating curves were used to compare the predictive ability of each AKI definition for the occurrence of adverse outcomes (death, rehospitalization, dialysis).

RESULTS

AKI by any definition occurred in 38.3% (244/637) of cases and was associated with an increased incidence of 30-day (32.3 vs. 6.9%, χ(2) = 70.1; p < 0.001) and 1-year adverse outcomes (67.5 vs. 31.0%, χ(2) = 81.4; p < 0.001). Most importantly, there was a stepwise increase in primary outcome with increasing stages of AKI severity using RIFLE, KDIGO, or AKIN (p < 0.001). In direct comparison, there were only small differences in predictive abilities between RIFLE and KDIGO and WRF concerning clinical outcomes at 30 days (AUC 0.76 and 0.74 vs. 0.72, χ(2) = 5.6; p = 0.02) as well as for KDIGO and WRF at 1 year (AUC 0.67 vs. 0.65, χ(2) = 4.8; p = 0.03).

CONCLUSION

During admission for HF, the benefits of using newer AKI classification systems (RIFLE, AKIN, KDIGO) lie with the ability to identify those patients with more severe degrees of AKI who will go on to experience adverse events at 30 days and 1 year. The differences in terms of predictive abilities were only marginal.

Long-term prognostic impact after acute kidney injury in patients with acute heart failure

The relationship between the short-term prognosis of acute heart failure (AHF) and acute kidney injury (AKI) using the risk, injury, failure, and end stage (RIFLE) criteria has already been reported, however, the relationship between the long-term prognosis and AKI has not. We investigated the relationship between the long-term prognosis after discharge and AKI using the RIFLE criteria. Five hundred patients with AHF admitted to our intensive care unit were analyzed. Patients were assigned to a no AKI (n = 156), Class R (risk; n = 201), Class I (injury; n = 73), or Class F (failure; n = 70) using the most severe RIFLE classifications during hospitalization. We evaluated the relationships between the RIFLE classifications and any-cause death, and HF events including death and readmission for HF within 1 year. A multivariate logistic regression model found that Class I (P = 0.013, OR: 2.768; 95% CI: 1.236-6.199) and Class F (P < 0.001, OR: 7.920; 95% CI: 3.497-17.938) were independently associated with any-cause death, and Class F was associated with HF events (P = 0.001, OR: 3.486; 95% CI: 1.669-7.281). The Kaplan-Meier survival curves showed the prognosis, including death, to be significantly poorer in Class I than in no AKI and Class R, to be significantly poorer in Class F than in no AKI, Class R, and Class I, and the prognosis including HF events to be significantly poorer in Class F than in no AKI, Class R, and Class I. The presence of severe AKI (Class I and F) was independently associated with long-term mortality for AHF.

Prevalence of acute kidney injury and prognostic significance in patients with acute myocarditis

Objective

Myocarditis is an inflammation of the myocardium. The condition is commonly associated with rapid disease progression and often results in profound shock. Impaired renal function is the result of impairment in end-organ perfusion and is highly prevalent among critically ill patients. The aim of this study was to evaluate the incidence of acute kidney injury (AKI) and identify the relationship between AKI and the prognosis of patients with acute myocarditis.

Design, Measurements and Main Results

This retrospective study reviewed the medical records of 101 patients suffering from acute myocarditis between 1996 and 2011. Sixty of these patients (59%) developed AKI within 48 hours of being hospitalized. AKI defined as AKIN stage 3 (p = 0.007) and SOFA score (p = 0.03) were identified as predictors of in-hospital mortality in multivariate analysis. The conditional effect plot of the estimated risk against SOFA score upon admission categorized according to the AKIN stages showed that the risk of in-hospital mortality was highest among patients in AKIN stage 3 with a high SOFA score.

Conclusions

Among patients with acute myocarditis, AKI defined as AKIN stage 3 and elevated SOFA score were associated with unfavorable outcomes. AKIN classification is a simple, reproducible, and easily applied evaluation tool capable of providing objective information related to the clinical prognosis of patients with acute myocarditis.

Role of biomarkers in the diagnosis and prognosis of acute kidney injury in patients with cardiorenal syndrome

Cardiac and renal disease frequently coexist but have long been difficult to diagnose in a timely manner and treat effectively. Noninvasive and cost-effective biomarkers are needed to help identify cardiac patients who are at risk of acute kidney injury early in the course of disease. Biomarkers can provide insights into underlying mechanisms and lead to a better understanding of complex disease states such as the cardiorenal syndrome, which can lead to better therapies and, ultimately, to improved patient outcomes. The natriuretic peptides are established biomarkers in heart failure and have set the standard for how a well-validated biomarker can be useful for diagnosis/prognosis, monitoring response to therapy and chronic disease management. For patients with acute kidney injury in the setting of cardiac disease, new biomarkers such as neutrophil gelatinase-associated lipocalin, cystatin C, kidney injury molecule-1 and IL-18 are emerging as early signals of renal dysfunction prior to any elevations in serum creatinine. Other promising candidate biomarkers for the early diagnosis of acute kidney injury include osteopontin, N-acetyl-b-d-glucosaminidase, stromal cell-derived factor-1 and exosomes. More research with all of these novel biomarkers is needed; however, the early results are very promising.

Cardiorenal syndrome type 1: pathophysiological crosstalk leading to combined heart and kidney dysfunction in the setting of acutely decompensated heart failure

Cardiorenal syndrome (CRS) type 1 is characterized as the development of acute kidney injury (AKI) and dysfunction in the patient with acute cardiac illness, most commonly acute decompensated heart failure (ADHF). There is evidence in the literature supporting multiple pathophysiological mechanisms operating simultaneously and sequentially to result in the clinical syndrome characterized by a rise in serum creatinine, oliguria, diuretic resistance, and in many cases, worsening of ADHF symptoms. The milieu of chronic kidney disease has associated factors including obesity, cachexia, hypertension, diabetes, proteinuria, uremic solute retention, anemia, and repeated subclinical AKI events all work to escalate individual risk of CRS in the setting of ADHF. All of these conditions have been linked to cardiac and renal fibrosis. In the hospitalized patient, hemodynamic changes leading to venous renal congestion, neurohormonal activation, hypothalamic-pituitary stress reaction, inflammation and immune cell signaling, systemic endotoxemic exposure from the gut, superimposed infection, and iatrogenesis all contribute to CRS type 1. The final common pathway of bidirectional organ injury appears to be cellular, tissue, and systemic oxidative stress that exacerbate organ function. This review explores in detail the pathophysiological pathways that put a patient at risk and then effectuate the vicious cycle now recognized as CRS type 1.

Acute kidney injury risk in patients with ST-segment elevation myocardial infarction at presentation to the ED

INTRODUCTION

Acute kidney injury (AKI) is common in acute myocardial infarction (AMI) patients and has serious prognostic implications. The early identification of patients at risk of developing AKI at the emergency department (ED) can reduce its incidence.

METHODS

Patients with ST-segment elevation myocardial infarction (STEMI) at the ED were included. Associated factors playing a role at ED presentation and during hospitalization were collected, and independent risk factors of developing AKI were assessed.

RESULTS

Mean age among patients (n = 406, 69.7% male) was 62.5 ± 12.5 years. At ED admission, the mean glomerular filtration rate (GFR) was 70.5 ± 28.1 mL/min per 1.73 m(2), and 140 (34.5%) patients had a GFR <60 mL/min per 1.73 m(2). Eighty-three patients (20.4%) developed AKI: 47 (11.6%) with stage 1, 26 (6.4%) with stage 2 and 10 (2.5%) with stage 3. Mortality was 11.8% and was higher in patients with AKI (34.9% vs 5.9%, P < .0001). Univariate analysis disclosed age, reduced GFR at presentation, severe Killip class, heart rate and longer door-to-needle time as risk factors to develop AKI. Moreover, these patients received less β-blocker and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker in the ED. Multivariate analysis revealed that age, Killip class, heart rate, door-to-needle time, and β-blocker non-use were independent factors associated with AKI. These factors provided the ED physician with good accuracy in identifying patients at high risk of developing AKI.

CONCLUSION

Factors associated with AKI in STEMI patients allowed physicians to identify patients at high risk in the ED. Moreover, reduced door-to-needle time and β-blocker use were associated with renal protection in AMI patients.

Acute and acute-on-chronic kidney injury of patients with decompensated heart failure: impact on outcomes

Background

Acute worsening of renal function, an independent risk factor for adverse outcomes in acute decompensated heart failure (ADHF), occurs as a consequence of new onset kidney injury (AKI) or acute deterioration of pre-existed chronic kidney disease (CKD) (acute-on-chronic kidney injury, ACKI). However, the possible difference in prognostic implication between AKI and ACKI has not been well established.

Methods

We studied all consecutive patients hospitalized with ADHF from 2003 through 2010 in Nanfang Hospital. We classified patients as with or without pre-existed CKD based on the mean estimated glomerular filtration rate (eGFR) over a six-month period before hospitalization. AKI and ACKI were defined by RIFLE criteria according to the increase of the index serum creatinine.

Results

A total of 1,005 patients were enrolled. The incidence of ACKI was higher than that of AKI. The proportion of patients with diuretic resistance was higher among patients with pre-existed CKD than among those without CKD (16.9% vs. 9.9%, P = 0.002). Compared with AKI, ACKI was associated with higher risk for in-hospital mortality, long hospital stay, and failure in renal function recovery. Pre-existed CKD and development of acute worsening of renal function during hospitalization were the independent risk factors for in-hospital death after adjustment by the other risk factors. The RIFLE classification predicted all-cause and cardiac mortality in both AKI and ACKI.

Conclusions

Patients with ACKI were at greatest risk of adverse short-term outcomes in ADHF. Monitoring eGFR and identifying CKD should not be ignored in patients with cardiovascular disease.

Nephrotoxicity of vancomycin in patients with methicillin-resistant Staphylococcus aureus bacteraemia

AIM

Vancomycin and teicoplanin are the two most used glycopeptides for the treatment of methicillin-resistant Staphylococcus aureus (MRSA). Vancomycin is suspected to have more nephrotoxicity but this has not been clearly established. The aim of this study was to assess its nephrotoxicity by a consensus definition of acute kidney injury (AKI): the risk (R), injury (I), failure (F), loss and end-stage renal disease (RIFLE) classification.

METHODS

Patients with MRSA bacteraemia who were prescribed either vancomycin or teicoplanin between 2003 and 2008 were classified. Patients who developed AKI were classified by RIFLE criteria. Variables such as comorbidities, laboratory data and medical cost information were also obtained from the database. Outcomes determined were: (i) the rate of nephrotoxicity and mortality; and (ii) the association of nephrotoxicity with the length of hospital stay and costs.

RESULTS

The study included 190 patients (vancomycin 33, teicoplanin 157). Fifteen patients on vancomycin and 27 patients on teicoplanin developed AKI (P = 0.0004). In the vancomycin group, four, eight and three patients were classified to RIFLE criteria R, I and F, respectively. In the teicoplanin group, 17, nine and one patient were classified to RIFLE criteria R, I and F, respectively. Kaplan-Meier analysis showed significant difference in time to nephrotoxicity for the vancomycin group compared to the teicoplanin group. No significant differences were found between the groups in terms of total mortality, length of hospital stay and costs.

CONCLUSION

The study data suggest that vancomycin is associated with a higher likelihood of nephrotoxicity using the RIFLE classification.

Plasma neutrophil gelatinase-associated lipocalin for the prediction of acute kidney injury in acute heart failure

Introduction

The accurate prediction of acute kidney injury (AKI) in patients with acute heart failure (AHF) is an unmet clinical need. Neutrophil gelatinase-associated lipocalin (NGAL) is a novel sensitive and specific marker of AKI.

Methods

A total of 207 consecutive patients presenting to the emergency department with AHF were enrolled. Plasma NGAL was measured in a blinded fashion at presentation and serially thereafter. The potential of plasma NGAL levels to predict AKI was assessed as the primary endpoint. We defined AKI according to the AKI Network classification.

Results

Overall 60 patients (29%) experienced AKI. These patients were more likely to suffer from pre-existing chronic cardiac or kidney disease. At presentation, creatinine (median 140 (interquartile range (IQR), 91 to 203) umol/L versus 97 (76 to 132) umol/L, P < 0.01) and NGAL (114.5 (IQR, 67.1 to 201.5) ng/ml versus 74.5 (60 to 113.9) ng/ml, P < 0.01) levels were significantly higher in AKI compared to non-AKI patients. The prognostic accuracy for measurements obtained at presentation, as quantified by the area under the receiver operating characteristic curve was mediocre and comparable for the two markers (creatinine 0.69; 95%CI 0.59 to 0.79 versus NGAL 0.67; 95%CI 0.57 to 0.77). Serial measurements of NGAL did not further increase the prognostic accuracy for AKI. Creatinine, but not NGAL, remained an independent predictor of AKI (hazard ratio (HR) 1.12; 95%CI 1.00 to 1.25; P = 0.04) in multivariable regression analysis.

Conclusions

Plasma NGAL levels do not adequately predict AKI in patients with AHF.

Comparative effects of nesiritide and nitroglycerin on renal function, and incidence of renal injury by traditional and RIFLE criteria in acute heart failure

BACKGROUND

Acute renal insufficiency is associated with poorer outcomes in heart failure. Data regarding the renal effects of vasodilatory therapy in acute heart failure are inconclusive.

HYPOTHESIS

Nesiritide and nitroglycerin are associated with differing effects on the incidence of acute renal injury and glomerular filtration rate changes.

METHODS

A retrospective cohort study of patients hospitalized with acute congestive heart failure who received intravenous nesiritide or nitroglycerin for ≥6 hours. Acute kidney injury was assessed by risk, injury, failure, loss, and end stage (RIFLE) classification (creatinine/GFR criteria) and by traditional acute rise in creatinine of 0.3 mg/dL or 25%. Secondary endpoints included change in estimated glomerular filtration rate, serum creatinine, serum blood urea nitrogen, blood pressure, and urine output.

RESULTS

A total of one hundred and thirty-one patients (age 57 ± 12 years, 67% male, left ventricular ejection fraction 38 ± 35%, 30% ischemic) received nesiritide (N = 37) or nitroglycerin (N = 94). Diuretic regimen and doses were similar in both the groups. Mean duration of therapy was not different (nesiritide 38.6 ± 35.7 h vs nitroglycerin 30.7 ± 22.6 h, P = .13). No differences were detected in incidence of renal injury using either criteria (RIFLE: nesiritide 19% vs nitroglycerin 22%, P = .88; traditional: 22% vs 34%, P = .16); however, glomerular filtration rate declined (-1 ± 18 mL/min vs -9 ± 21 mL/min, P = .03) and blood urea nitrogen increased (-0.2 ± 9.9 mg/dL vs 4.2 ± 9.1 mg/dL, P = .02) to a greater degree with nitroglycerin. Nesiritide was associated with lower hourly blood pressures and a higher incidence of systolic blood pressure <80 mm Hg.

CONCLUSION

The incidence of renal injury was not different between nesiritide- and nitroglycerin-treated patients with acute heart failure; however, nitroglycerin was associated with a decline in glomerular filtration rate and increase in blood urea nitrogen despite higher baseline and on treatment blood pressures.