The cardiorenal syndrome: do we need a change of strategy or a change of tactics? J Am Coll Cardiol. 2009;53:597-599. [PMID: 19215834 DOI: 10.1016/j.jacc.2008.11.012]

Cardiorenal Syndrome: An Evolutionary Appraisal

A recent American Heart Association Scientific Statement and Presidential Advisory recognized a new syndrome, the cardiovascular-kidney-metabolic syndrome. This expands our understanding of what has been called cardiorenal syndrome by incorporating the pathophysiological interrelatedness of metabolic risk factors into the previous concept of cardiorenal syndrome. Importantly, perturbation of cardiac or renal physiology combines to produce significant detrimental outcomes. The cardiorenal syndrome is a significant part of the cardiovascular-kidney-metabolic syndrome and contributes to health care cost, disability, and mortality. It is a vexing malady that has generated considerable interest. To understand the syndrome evaluation of its teleological origins is important. In life's beginning, eukaryotes acquired exocytosis for excretion, formed tubular secretory systems for clearance, and a mesenchymal nucleic acid vasoform for nutritional distribution. Those structures progressed to cardiovascular and renal systems of evolving organisms, whose migration to rivers and land imposed complex, coordinated, homeostatic roles to maintain intravascular stability. Tissue mineralization of vertebrate endoskeleton added renal calcium balance regulation, which in kidney failure results in cardiovascular calcification. Insight into cardiorenal disease can be traced to ancient Egyptian and Chinese medicine, through the Scientific Revolution, and into current insights regarding human physiology and pathophysiology. The post-World War II epidemic of cardiovascular mortality generated considerable information on cardiovascular disease, which being higher in patients with kidney disease, drew increasing health concerns. The cardiorenal syndrome was formally introduced in this setting with a focus on ultrafiltration to manage volume overload. An evolutionary review of insight into cardiorenal syndrome will help us better understand the new cardiovascular-kidney-metabolic syndrome.

Renal Arterial and Venous Doppler in Cardiorenal Syndrome: Pathophysiological and Clinical Insights

In recent decades, there has been considerable effort in investigating the clinical utility of renal Doppler measurements in both cardiovascular and renal disorders. In particular, a measure of renal arterial resistance, the renal resistive index (RRI), has been demonstrated to predict chronic kidney disease progression and acute kidney injury in different clinical settings. Furthermore, it is linked to a poorer prognosis in individuals suffering from chronic heart failure. Examining the renal venous flow through pulsed Doppler can offer additional insights into renal congestion and cardiovascular outcomes for these patients. This review seeks to summarize the existing data concerning the clinical significance of arterial and venous renal Doppler measurements across various cardiovascular and renal disease contexts.

Renal Oxygen Demand and Nephron Function: Is Glucose a Friend or Foe?

The kidneys and heart work together to balance the body's circulation, and although their physiology is based on strict inter dependence, their performance fulfills different aims. While the heart can rapidly increase its own oxygen consumption to comply with the wide changes in metabolic demand linked to body function, the kidneys physiology are primarily designed to maintain a stable metabolic rate and have a limited capacity to cope with any steep increase in renal metabolism. In the kidneys, glomerular population filters a large amount of blood and the tubular system has been programmed to reabsorb 99% of filtrate by reabsorbing sodium together with other filtered substances, including all glucose molecules. Glucose reabsorption involves the sodium-glucose cotransporters SGLT2 and SGLT1 on the apical membrane in the proximal tubular section; it also enhances bicarbonate formation so as to preserve the acid-base balance. The complex work of reabsorption in the kidney is the main factor in renal oxygen consumption; analysis of the renal glucose transport in disease states provides a better understanding of the renal physiology changes that occur when clinical conditions alter the neurohormonal response leading to an increase in glomerular filtration pressure. In this circumstance, glomerular hyperfiltration occurs, imposing a higher metabolic demand on kidney physiology and causing progressive renal impairment. Albumin urination is the warning signal of renal engagement over exertion and most frequently heralds heart failure development, regardless of disease etiology. The review analyzes the mechanisms linked to renal oxygen consumption, focusing on sodium-glucose management.

A Glimpse Into the Future of Transcatheter Interventional Heart Failure Therapies

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HF affects millions of patients every year, adding a significant financial burden to global health care systems.

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This review discusses the role of novel transcatheter-based therapies for the management of HF.

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Ongoing clinical trials will provide answers on the potential clinical benefits of these technologies in HF outcomes.

Chronic heart failure is one of the most debilitating chronic conditions affecting millions of people and adding a significant financial burden to health care systems worldwide. Despite the significant therapeutic advances achieved over the last decade, morbidity and mortality remain high. Multiple catheter-based interventional therapies targeting different physiological and anatomical targets are already under different stages of clinical investigation. The present paper provides a technical overview of the most relevant catheter-based interventional therapies under clinical investigation.

Oxidative Stress Markers and Modified Model for End-Stage Liver Disease Are Associated with Outcomes in Patients with Advanced Heart Failure Receiving Bridged Therapy with Continuous-Flow Left Ventricular Assist Devices

Left ventricular assist device (LVAD) is well established as an alternative treatment for end-stage heart failure (HF) patients. The aim of the study was to determine the prognostic value of oxidative stress markers and the modified Model for End-Stage Liver Disease (modMELD) in patients receiving bridged therapy with continuous-flow LVAD. We prospectively analyzed 36 end-stage HF patients who received LVAD therapy between 2015 and 2018. The total antioxidant capacity (TAC) and total oxidant status (TOS) were measured by the methods described by Erel. The oxidative stress index (OSI) was defined as the ratio of the TOS to TAC levels. The modMELD scores were calculated based on the serum bilirubin, creatinine, and albumin levels. The patients’ median age was 58 (50–63.0) years. During the 1.5-years follow-up, a major adverse cardiac event—MACE (death, stroke, or pump thrombosis) was observed in 17 patients (47.2%). The area under the receiver operating characteristics curves (AUCs) indicated a good prognostic power of TAC (AUC 0.7183 (0.5417–0.8948)), TOS (AUC 0.9149 (0.8205–0.9298)), OSI (AUC 0.9628 (0.9030–0.9821)), and modMELD (AUC 0.87 (0.7494–0.9905)) to predict a MACE. Oxidative stress markers serum concentrations, as well as the modMELD score, allow the identification of patients with a risk of MACE.

Biomarkers in Cardiorenal Syndrome

Cardiorenal syndrome is a clinical manifestation of the bidirectional interaction between the heart and kidney diseases. Over the last years, in patients with cardiovascular diseases, several biomarkers have been studied in order to better assess renal function as well as to identify patients prone to experiencing chronic or acute worsening of renal function. The aim of this review is to focus on the possible clinical usefulness of the most recent biomarkers in the setting of cardiorenal syndrome.

VExUS Nexus: Bedside Assessment of Venous Congestion

Organ dysfunction in the setting of heart failure is mainly determined by backward transmission of increased right atrial pressure. Although traditional point-of-care ultrasound applications such as inferior vena cava and lung ultrasound have been increasingly incorporated in the clinical care of congestive heart failure, they do not directly evaluate the hemodynamic consequences of high right atrial pressure on organ blood flow. Congestion induces alterations in the venous flow patterns of abdominal organs that can be readily assessed using Doppler imaging. These alterations have been consistently associated with congestive organ dysfunction and adverse clinical outcomes. In this article, we provide a comprehensive overview of the bedside assessment of venous congestion using Doppler imaging. The review focuses mainly on the normal and abnormal Doppler patterns of the hepatic, portal, and intrarenal veins along with clinical examples of how to incorporate this tool in the management of patients with venous congestion.

MELD and MELD XI Scores as Predictors of Mortality After Pericardiectomy for Constrictive Pericarditis

OBJECTIVE

To assess the association between the preoperative model for end-stage liver disease (MELD) and MELD-XI (exclude international normalized ratio) score and outcomes in patients undergoing pericardiectomy for constrictive pericarditis.

PATIENTS AND METHODS

Patients >18 years of age undergoing pericardiectomy for constrictive pericarditis between January 1, 2007, and October 12, 2017, were analyzed with data for MELD and MELD-XI score calculation within 30 days preoperatively. The association between the MELD and MELD-XI scoring systems and risk of postoperative outcomes was assessed in regression models adjusting for relevant covariates. The primary outcome was operative mortality (death within 90 days or in hospital). Secondary outcomes included various measures of postoperative morbidity.

RESULTS

A total of 175 and 226 patients had data for MELD/MELD-XI, respectively. Ninety-day mortality was 8.7%. When stratified into tertiles of MELD-XI, the unadjusted risk of 90-day mortality was 2.7%, 8.2%, and 16.0%, respectively. In Cox regression models fitted for MELD-XI and MELD, higher scores associated with increased risk of mortality (P<.001 for both). In secondary multivariable analyses, both MELD-XI and MELD were associated with increased incidence of renal failure and greater levels of chest-tube output and transfusion, whereas MELD-XI was additionally associated with prolonged intubation and extended intensive care unit and hospital stays.

CONCLUSION

Among patients undergoing pericardiectomy for constrictive pericarditis, MELD-XI and MELD were associated with increased postoperative morbidity and mortality. Although the simpler MELD-XI score generally performed as well or better than MELD as a correlate of various outcomes, both scores can serve as a simple yet robust risk stratification tool for patients undergoing pericardiectomy for constrictive pericarditis.

Higenamine Improves Cardiac and Renal Fibrosis in Rats With Cardiorenal Syndrome via ASK1 Signaling Pathway

The pathogenesis of cardiorenal syndrome (CRS) is very complex, and currently there is no effective treatment for CRS. Higenamine (HI) has been shown to improve cardiac function in rats with heart failure. However, the role of higenamine in CRS remains unknown. Here, in vitro, higenamine treatment markedly reduced neonatal rat cardiac fibroblast collagen synthesis and inhibited neonatal rat cardiac myocyte hypertrophy. In our study, a rat model of type 2 CRS was induced by left anterior descending coronary artery ligation combined with 5/6 subtotal nephrectomy (STNx). Higenamine treatment decreased serum creatinine (Scr), blood urea nitrogen, and brain natriuretic peptide levels and was capable of improving left ventricular remodeling and systolic function in CRS rats, accompanied with decreased expression of transforming growth factor-β1 (TGF-β1), α-smooth muscle actin (α-SMA) and collagen I (Col1A1). Moreover, higenamine significantly inhibited the protein expression of phosphorylated apoptosis signal-regulated kinase 1 (p-ASK1) and downstream mitogen-activated protein kinases (MAPK) (ERK, P38)/NF-κB in cardiorenal tissues of CRS rats and neonatal rat cardiac fibroblast/neonatal rat cardiac myocyte cells. Our study demonstrated that higenamine improved cardiorenal function in CRS rats and attenuated heart and kidney fibrosis possibly via targeting ASK1/MAPK (ERK, P38)/NF-κB signaling pathway. This finding extends our knowledge on the role of higenamine in cardiorenal fibrosis, providing a potential target to prevent the progression of CRS.

Semi-quantification of renal perfusion using 99mTc-DTPA in systolic heart failure: a feasibility study

BACKGROUND

Renal scintigraphy with ^99mTc-diethylenetriaminepentaacetic acid (DTPA) may be used to study renal perfusion (RP) in heart failure (HF) patients. The goal of this study was to establish a new method to assess RP in patients with systolic HF.

METHODS

In this retrospective, single-center, observational study, 86 subjects with left ventricular ejection fraction ≤ 45% and 31 age-matched subjects without HF underwent renal scintigraphy with ^99mTc-DTPA. Patients with HF were classified into two categories according to the New York Heart Association (NYHA) functional class, i.e., moderate HF with NYHA functional class I or II and severe HF with NYHA functional class III or IV. The first-pass time-activity curve of the renal scintigraph was recorded. The GFR was determined by Gates' method. The time to peak perfusion activity (T_p), the slope of the perfusion phase (S_p), the slope of the washout phase (S_w), and glomerular filtration rate (GFR) in the study were obtained. Differences between groups were assessed by one-way analysis of variance with the Bonferroni post hoc test and rank-sum test.

RESULTS

RP in HF was impaired despite comparable GFRs between the control and HF groups. RP in HF was characterized by a longer T_p and a shallower S_p and S_w. The primary parameter (T_p) was significantly prolonged in patients with HF (41.63 ± 12.22 s in severe HF vs. 26.95 ± 6.26 s in moderate HF vs. 17.84 ± 3.17 s in control, P < 0.001). At a cutoff point of 22 s, there was a high sensitivity (0.895) and specificity (0.935) in identifying patients with HF.

CONCLUSIONS

Renal scintigraphy with ^99mTc-DTPA may represent a new and useful method to noninvasively monitor RP abnormalities in HF.

Impact of predictive value of Fibrosis-4 index in patients hospitalized for acute heart failure

BACKGROUND

Abnormalities in liver function tests commonly occur in patients with acute heart failure (AHF). The Fibrosis-4 (FIB4) index, a non-invasive and easily calculated marker, has been used for hepatic diseases and reflects adverse prognosis. It is not clearly established whether the FIB4 index at admission can predict adverse outcomes in patients with AHF.

METHODS AND RESULTS

From a multicenter AHF registry, we retrospectively evaluated 1162 consecutive patients admitted due to AHF (median age 78 [69-85] years and 702 patients [60.4%] were male). The FIB4 index at admission was calculated as: age (yrs) × aspartate aminotransferase [U/L]/(platelets count [10³/μL] × √alanine aminotransferase [U/L]. The median value of the FIB4 index at admission was 2.79. All-cause mortality and rehospitalization due to HF at 12 months were investigated as a composite endpoint and occurred in 142 (12.2%) patients and 232 (20%) patients, respectively. Kaplan-Meyer analysis shows a significant increase in the composite endpoint from the first to fourth quartile group of the FIB4 index values (log-rank, p < 0.001). Multivariate Cox regression model revealed the FIB4 index was an independent risk predictor for composite endpoint in patients with AHF (3 months: HR ratio 1.013 [95% Confidence interval (CI):1.001-1.025]; p = 0.03, 12 months: HR 1.015 [95% CI:1.005-1.025]; p = 0.003, respectively). However, neither aspartate aminotransferase, alanine aminotransferase, nor platelet count was found to be a significant predictor.

CONCLUSIONS

Hepatic dysfunction evaluated with the FIB4 index at admission is a predictor of the composite endpoint of all-cause mortality and rehospitalization in AHF patients.

Right Ventricular Function in Chronic Heart Failure: From the Diagnosis to the Therapeutic Approach

There is growing attention for the study of the right ventricle in cardiovascular disease and in particular in heart failure. In this clinical setting, right ventricle dysfunction is a significant marker of poor prognosis, regardless of the degree of left ventricular dysfunction. Novel echocardiographic methods allow for obtaining a more complete evaluation of the right ventricle anatomy and function as well as of the related abnormalities in filling pressures. Specific and effective therapies for the right ventricle dysfunction are still not well defined and this represents the most difficult and important challenge. This article focuses on available diagnostic techniques for studying right ventricle dysfunction as well as on the therapies for right ventricle dysfunction.

Positive association between intra-operative fluid balance and post-operative acute kidney injury in non-cardiac surgery: the NARA-AKI cohort study

BACKGROUND

Little is known about the association between intra-operative fluid balance (IFB) and post-operative acute kidney injury (AKI) in non-cardiac surgery.

METHODS

This is a retrospective cohort study. Adults who underwent non-cardiac surgery under general anesthesia from 2007 to 2011 at Nara Medical University Hospital were included. Those with obstetric or urological surgery, missing data, or pre-operative dialysis were excluded. Exposure of interest was IFB, defined as (amount of fluid administration - urine output - amount of bleeding)/body weight. Outcome variable was post-operative AKI within 1 week after surgery. Data were analyzed using logistic regression models and restricted cubic spline (RCS) analysis.

RESULTS

Among 5168 subjects, AKI was observed in 309 (6.0%). Higher IFB (per 1 standard deviation) was independently associated with post-operative AKI after adjustment for potential confounders (odds ratio [95% confidence interval] of 1.18 [1.06-1.31]). The RCS curve showed an increase in expected probability of AKI associated with increase in IFB above 40 mL/kg. Subgroup analyses indicated higher IFB was especially associated with AKI among those with lower serum albumin, higher C-reactive protein, or positive proteinuria. The association was similar across intra-operative urine output or amount of bleeding (p for interaction 0.34 and 0.47, respectively), suggesting the association was not due to intra-operative oliguria or large amount of bleeding necessitating volume resuscitation.

CONCLUSIONS

Higher IFB was independently associated with increase in post-operative AKI. Excessive fluid administration might have caused renal congestion and subsequent AKI. Avoiding fluid overload might be important in prevention of AKI.

Fluid Overload in Special Pediatric Cohorts With Anomalous Origin of the Left Coronary Artery From the Pulmonary Artery Following Surgical Repair

OBJECTIVE

To investigate the prevalence, risk factors, and clinical outcomes associated with early fluid overload (FO) in a special group of pediatric patients undergoing repair of anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA).

DESIGN

It was a retrospective study performed with multiple variable regression analysis.

SETTING

A single cardiac surgical institution.

PARTICIPANTS

Eighty-eight patients younger than 18 years of age undergoing ALCAPA surgical repair with cardiopulmonary bypass were recruited at the authors' institution from June 2010 to September 2017.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

Of 88 pediatric patients with ALCAPA after surgical repair, 37.5% developed early FO, defined as fluid accumulation ≥5% within the period from surgery until midnight of postoperative day 1. Patients with early FO were younger, weighed less, and had worse preoperative cardiac dysfunction. With logistic regression analysis, being underweight was confirmed to be a risk factor for FO development (odds ratio, 8.66; 95% confidence interval, 2.83-26.52; p < 0.001). Early FO also predicted severe acute kidney injury, respiratory morbidity, and low cardiac output syndrome after reimplantation procedure. Patients with early FO also had significantly longer mechanical ventilation hours (p  <  0.001), intensive care unit length of stay (p = 0.003), and hospital length of stay (p = 0.009).

CONCLUSION

Early FO ≥5% has been linked to adverse postoperative outcomes in pediatric patients undergoing repair for ALCAPA. The use of restrictive fluid management is crucial for patients who have lower weight and poor myocardial function before and after complex surgical procedures such as in ALCAPA settings.

Doppler-Derived Renal Venous Stasis Index in the Prognosis of Right Heart Failure

Background Persistent congestion with deteriorating renal function is an important cause of adverse outcomes in heart failure. We aimed to characterize new approaches to evaluate renal congestion using Doppler ultrasonography. Methods and Results We enrolled 205 patients with suspected or prediagnosed pulmonary hypertension (PH) undergoing right heart catheterization. Patients underwent renal Doppler ultrasonography and assessment of invasive cardiopulmonary hemodynamics, echocardiography, renal function, intra-abdominal pressure, and neurohormones and hydration status. Four spectral Doppler intrarenal venous flow patterns and a novel renal venous stasis index (RVSI) were defined. We evaluated PH-related morbidity using the Cox proportional hazards model for the composite end point of PH progression (hospitalization for worsening PH, lung transplantation, or PH-specific therapy escalation) and all-cause mortality for 1-year after discharge. The prognostic utility of RVSI and intrarenal venous flow patterns was compared using receiver operating characteristic curves. RVSI increased in a graded fashion across increasing severity of intrarenal venous flow patterns (P<0.0001) and was significantly associated with right heart and renal function, intra-abdominal pressure, and neurohormonal and hydration status. During follow-up, the morbidity/mortality end point occurred in 91 patients and was independently predicted by RVSI (RVSI in the third tertile versus referent: hazard ratio: 4.72 [95% CI, 2.10-10.59; P<0.0001]). Receiver operating characteristic curves suggested superiority of RVSI to individual intrarenal venous flow patterns in predicting outcome (areas under the curve: 0.789 and 0.761, respectively; P=0.038). Conclusions We propose RVSI as a conceptually new and integrative Doppler index of renal congestion. RVSI provides additional prognostic information to stratify PH for the propensity to develop right heart failure. Clinical Trial Registration URL: https://www.clinicaltrials.gov/. Unique identifier: NCT03039959.

Risk indicators for acute kidney injury in cardiogenic shock

PURPOSE

In critical illness, the relation between the macrocirculation, microcirculation and organ dysfunction, such as acute kidney injury (AKI), is complex. This study aimed at identifying predictors for AKI in patients with cardiogenic shock.

MATERIALS AND METHODS

Thirty-nine adult cardiogenic shock patients, with an admission creatinine <200 μmol l^-1, and whose microcirculation was measured within 48 h were enrolled. Patient data were analyzed if AKI stage ≥1 developed according to the Kidney Disease/Improving Outcomes classification within 48 h after admission. Variables with a p < .05 in the univariate analysis were considered for analysis with logistic regression.

RESULTS

Twenty-four patients (61.5%) developed AKI within 48 h. The group that developed AKI had higher central venous pressures (CVP), lower diastolic arterial blood pressures and mean perfusion pressures, higher maximum ventilator pressures as well as positive end expiratory pressures and were treated with higher dosages of dobutamine. There was no difference of the microcirculation. In the multivariate logistic regression analysis, CVP was the only independent predictor for AKI (OR 1.241; 95% CI 1.030-1.495; p = .023).

CONCLUSIONS

In this population of patients with cardiogenic shock, CVP was associated with the development of AKI.

Renal Venous Pattern: A New Parameter for Predicting Prognosis in Heart Failure Outpatients

Aim of the study: In chronic heart failure (CHF) patients, renal congestion plays a key role in determining the progression of renal dysfunction and a worse prognosis. The aim of this study was to define the role of Doppler venous patterns reflecting renal congestion that predict heart failure progression. Methods: We enrolled outpatients affected by CHF, in stable clinical conditions and in conventional therapy. All patients underwent a clinical evaluation, routine chemistry, an echocardiogram and a renal echo-Doppler. Pulsed Doppler flow recording was performed at the level of interlobular renal right veins in the tele-expiratory phase. The venous flow patterns were divided into five groups according to the fluctuations of the flow. Type A and B were characterized by a continuous flow, whereas type C was characterized by a short interruption or reversal flow during the end-diastolic or protosystolic phase. Type D and E were characterized by a wide interruption and/or reversal flow. The occurrence of death and/or of heart transplantation and/or of hospitalization due to heart failure worsening was considered an event during follow-up. Results: During a median follow-up of 38 months, 126 patients experienced the considered end-point. Venous pattern C (HR 4.04; 95% CI: 2.14–7.65; p < 0.001), pattern D (HR 7.16; 95% CI: 3.69–13.9; p < 0.001) and pattern E (HR 8.94; 95% CI: 4.65–17.2; p < 0.001) were all associated with events using an univariate Cox regression analysis. Moreover, both the presence of pattern C (HR: 1.79; 95% CI: 1.09–2.97; p: 0) and of pattern D or E (HR: 1.90; 95% CI: 1.16–3.12; p: 0.011) remained significantly associated to events using a multivariate Cox regression analysis after correction for a reference model with an improvement of the overall net reclassification index (0.46; 95% CI 0.24–0.68; p < 0.001). Conclusions: Our findings demonstrate the independent and incremental role of Doppler venous patterns reflecting renal congestion in predicting HF progression among CHF patients, thus suggesting its possible utility in daily clinical practice to better characterize patients with cardio-renal syndrome.

Heart-Kidney Interactions in Cardiorenal Syndrome Type 1

The exact significance of kidney function deterioration during acute decompensated heart failure (ADHF) episodes is still under debate. Several studies reported a wide percentage of worsening renal function (WRF) in ADHF patients ranging from 20% to 40%. This is probably because of different populations enrolled with different baseline kidney and cardiac function, varying definition of acute kidney injury (AKI), etiology of kidney dysfunction (KD), and occurrence of transient or permanent KD over the observational period. Current cardiorenal syndrome classification does not distinguish among the mechanisms leading to cardiac and renal deterioration. Cardiorenal syndrome type 1 (CRS-1) is the result of a combination of neurohormonal activation, fluid imbalance, arterial underfilling, increased renal and abdominal pressure, and aggressive decongestive treatment. A more complete mechanistic approach to CRS-1 should include evaluation of baseline kidney function, timing, course and magnitude of KD, and introduction of specific biomarkers able to identify early kidney damage. Therefore, clinical and laboratory parameters may yield a different combination among predisposing, precipitating, and amplifying factors that may influence cardiorenal syndrome development. Thus, CRS-1 is a heterogeneous syndrome that needs to be better defined and categorized taking into account clinical status, renal condition, and treatment. The application of universal definitions for WRF/AKI definition would be the first step to achieve a clear classification.

Alterations in apparent diffusion coefficient values of the kidney during the cardiac cycle: Evaluation with ECG-triggered diffusion-weighted MR imaging

PURPOSE

To evaluate dynamic changes in apparent diffusion coefficient (ADC) values of the kidney at different time points during the cardiac cycle using electrocardiographic (ECG)-triggered diffusion-weighted MR imaging in normal subjects, and to elucidate the differences in ADC values between the right and left kidneys during a cardiac cycle.

MATERIALS AND METHODS

The study was approved by our institutional review board and informed consent was obtained from subjects. Twenty healthy volunteers who underwent ECG-triggered diffusion-weighted MR imaging of the kidney were included. The differences in ADC values of each kidney during different cardiac phases were compared. Additionally, the differences in maximum and minimum ADC values between the right and left kidney were also evaluated.

RESULTS

ADC values in the right and left kidney changed significantly during the cardiac cycle (P < 0.00001). Maximum and minimum ADC values during the cardiac cycle of the left kidney were significantly higher (P = 0.026 and 0.017, respectively) than those of the right kidney. Maximum ADC value in the left kidney had a significantly strong positive correlation with the left renal vein ratio (r = 0.83, P < 0.00001). In the right kidney, maximum ADC showed a weakly positive correlation with the diameter of the right renal vein (r = 0.45, P = 0.048).

CONCLUSION

ADC values of the kidney obtained using ECG-triggered diffusion-weighted MR imaging change significantly during the cardiac cycle. Maximum (systolic) ADC during the cardiac cycle of the left kidney was significantly higher than that of the right kidney, probably due to the anatomical difference in the renal vein.

Prognostic Utility of Indoxyl Sulfate for Patients with Acute Coronary Syndrome

Aim: We investigated whether indoxyl sulfate (IS), a protein-bound uremic toxin, predicts prognosis after acute coronary syndrome (ACS).

Methods: Serum IS level was determined prospectively in 98 patients who underwent successful primary percutaneous coronary intervention for ACS. Patients on hemodialysis were excluded. The endpoint of this study was six-month composite events including death, nonfatal myocardial infarction, heart failure requiring hospitalization, and adverse bleeding events.

Results: During the mean follow-up period of 168 days, composite events occurred in 13.3% of cases. Serum IS level was significantly higher in subjects who developed composite events than in those without events (0.14 ± 0.11 mg/dl vs. 0.06 ± 0.04 mg/dl; p < 0.001). After adjusting for confounding factors, a Cox proportional hazard analysis revealed that the IS level (hazard ratio (HR): 10.6; 95% confidence interval (CI): 1.63–69.3, p = 0.01), hemoglobin level (HR: 0.61; 95% CI: 0.43–0.87; p < 0.01), and left ventricular ejection fraction (LVEF) (HR: 0.95; 95% CI: 0.91–0.99; p = 0.03) were independent predictive factors of composite events. Furthermore, IS level significantly conferred additional value to the combined established risks of LVEF and hemoglobin level for predicting the incidence of composite events (area under the curve: 0.82 vs. 0.88, p = 0.01; net reclassification improvement: 0.67, p = 0.01; and integrated discrimination improvement: 0.15, p < 0.01).

Conclusions: The assessment of serum IS level has prognostic utility for the management of ACS.

Cardiorenal Syndrome Type 1: Definition, Etiopathogenesis, Diagnostics and Treatment

Cardiorenal Syndrome Type 1 (CRS-1) is defined as an acute worsening of heart function leading to acute kidney injury and/or dysfunction. It is an important cause of hospitalization which affects the diagnosis as well as the prognosis and treatment of patients. The purpose of this paper is to analyze causes that lead to the development of cardiorenal syndrome type 1 and its clinical consequences, as well as to emphasize the clinical importance of its early detection. The clinical studies and professional papers dealing with etiopathogenesis, diagnosis and treatment of cardiorenal syndrome type 1, have been analyzed. The most important role in the occurrence of cardio renal syndrome type 1 is played by hemodynamic mechanisms, activation of neurohumoral systems, inflammation and imbalance between the production of reactive oxygen species (ROS) and nitric oxide (NO). Diagnosis of cardiorenal syndrome type 1 involves biomarkers of acute renal injury among which the most important are: neutrophil gelatinaseassociated lipocalin (NGAL), cystatin C, kidney injury molecule 1 (KIM-1), liver-type fatty acid binding protein (L-FABP), IL-18 and the values of nitrogen compounds in serum. In addition to a pharmacological therapy, various modalities of extracorporeal ultrafiltration are applied in treatment of CRS-1, particularly if there is resistance to the use of diuretic therapy. As opposed to the experimental models, in clinical practice acute renal injury is often diagnosed late so that the measures taken do not give the expected results and the protective role shown in experimental conditions do not give the same results. For all these reasons, it is necessary to analyze the pathophysiology of renal impairment in cardiorenal syndrome as well as detect early indicators of kidney injury that could have clinical benefit and positive impact on reducing the cost of treatment.

Getting to the Heart of the Matter: Review of Treatment of Cardiorenal Syndrome

Acute decompensated heart failure is a common cause of hospitalization with worsening kidney function or acute kidney injury often complicating the admission, which can result in further dysfunction of both systems in the form of a cardiorenal syndrome. Therapy in this arena has been largely empiric as rigorous clinical trial data to inform therapeutic choices are lacking. Here we review and discuss the available clinical evidence for common approaches to the management of this condition. A multidisciplinary approach to the care of patients with cardiorenal syndrome that relies on the experience of nephrologists and cardiologists to individualize treatment is critical given the paucity of rigorous clinical trial data.

Cardiorenal Syndrome: Diagnosis and Management

Cardiorenal syndrome (CRS) has not been well characterized in veterinary medicine, yet an accurate appreciation of the kidney and the cardiovascular system and their interactions may have practical clinical implications. A consensus for cardiovascular-renal axis disorders of dogs and cats was recently attempted. The outcome of patients with CRS is likely to improve with the increasing awareness and ability to identify and understand the pathophysiologic characteristics of CRS. The utilization of existing and emerging organ-specific biomarkers with greater sensitivities than conventional diagnostics forecast new opportunities to diagnose and manage cardiac disease.

Management of Congestion and Diuretic Resistance in Heart Failure

We present the case of a patient with heart failure and severe congestion who was responding poorly to diuretic therapy. We discuss the key problems concerning the pathophysiology and bedside therapeutic approach to congestion and fluid overload in this clinical setting, and we give practical suggestions to overcome congestion, especially in the setting of diuretic resistance and worsening renal function. We conclude that the application of key pharmacokinetic and pharmacodynamic principles of diuretic therapy, along with in-depth knowledge of the pathophysiology of heart failure, still represent the cornerstones for a correct approach to decongestive therapy in these patients.

Efficacy of extracorporeal ultrafiltration in patients with diuretic-resistant heart failure

Renal congestion contributes to the cardiorenal syndrome. There are some heart failure cases that are refractory to diuretic therapy. If the dose of diuretics is titrated, it leads to irreversible renal dysfunction. Early administration of tolvaptan is effective in treating fluid retention and congestion. However, in case of tolvaptan resistance, starting extracorporeal ultrafiltration (ECUM) at an early stage should be considered. Tolvaptan has been proven efficient, and we believe it should be incorporated with the classical method, ECUM. Herein, we present a case of successful application of ECUM to a heart failure patient refractory to any diuretics and tolvaptan.

[Acute cardiorenal syndromes]

Heart and kidney are closely interacting organs which function interdependently. Organ crosstalk between these two organs is based on humoral regulation and by inflammatory mediators, which are similar to those dominating systemic inflammation syndrome. The close interaction between heart and kidney results in organ dysfunction following both chronic and acute functional impairment of the respective counterpart. These changes are summarized under the term cardiorenal syndrome (CRS) which is subdivided into 5 types. In the setting of emergency medicine and intensive care units, CRS types 1 and 3 are the most common. CRS type 1 is characterized by acute kidney injury (AKI) developing as a consequence of acute heart failure. CRS type 3 is represented by acute cardiac failure following AKI, often occurring as a consequence of nephrotoxins. Diagnosis of CRS should preferably be made on basis of the Kidney Disease: Improving Global Outcomes (KDIGO) criteria for the diagnosis and staging of AKI. The cardiac diagnostic workup should include echocardiography, electrocardiogram (ECG), cardiac enzymes, and brain natriuretic peptide (BNP). The therapeutic approach in CRS is primarily aimed at treating the causative organ dysfunction. In case of CRS type 3 this means ensuring adequate kidney perfusion, cautious fluid management, and avoiding additional nephrotoxins. In case of diuretic resistant fluid overload, early initiation of extracorporeal fluid removal, preferably by renal replacement therapy, should be considered.

Kidney disease in heart failure: the importance of novel biomarkers for type 1 cardio-renal syndrome detection

Chronic kidney disease (CKD) in heart failure (HF) has been recognized as an independent risk factor for adverse outcome, although the most important clinical trials tend to exclude patients with moderate and severe renal insufficiency. Despite this common association, the precise pathophysiological connection and liaison between heart and kidney is partially understood. Moreover, is it not enough considering how much cardio-renal syndrome type 1 is attributable to previous CKD, and how much to new-onset acute kidney injury (AKI). Neither development of AKI, its progression and time nor duration is related to an adverse outcome. An AKI definition is not universally recognized, and many confounding terms have been used in literature: "worsening renal function", "renal impairment", "renal dysfunction", etc., are all names that contribute to misunderstanding, and do not facilitate an universal classification. Therefore, AKI development should be the consequence of the basal clinical characteristics of patients, different primitive kidney disease and hemodynamic status. AKI could also be the mirror of several underlying associated diseases poorly controlled. Finally, it is not clear which is the optimal laboratory tool for identifying patients with an increased risk of AKI. In the current report, we review the different kidney diseases' impact in HF, and we analyze the modalities for AKI recognition during HF focusing our attention about some new biomarkers with potential application in the current setting.

Update: Acute Heart Failure (VII): Nonpharmacological Management of Acute Heart Failure

Acute heart failure is a major and growing public health problem worldwide with high morbidity, mortality, and cost. Despite recent advances in pharmacological management, the prognosis of patients with acute decompensated heart failure remains poor. Consequently, nonpharmacological approaches are being developed and increasingly used. Such techniques may include several modalities of ventilation, ultrafiltration, mechanical circulatory support, myocardial revascularization, and surgical treatment, among others. This document reviews the nonpharmacological approach in acute heart failure, indications, and prognostic implications.

Evaluation of chronic kidney disease in chronic heart failure: From biomarkers to arterial renal resistances

Chronic kidney disease and its worsening are recurring conditions in chronic heart failure (CHF) which are independently associated with poor patient outcome. The heart and kidney share many pathophysiological mechanisms which can determine dysfunction in each organ. Cardiorenal syndrome is the condition in which these two organs negatively affect each other, therefore an accurate evaluation of renal function in the clinical setting of CHF is essential. This review aims to revise the parameters currently used to evaluate renal dysfunction in CHF with particular reference to the usefulness and the limitations of biomarkers in evaluating glomerular dysfunction and tubular damage. Moreover, it is reported the possible utility of renal arterial resistance index (a parameter associated with abnormalities in renal vascular bed) for a better assesment of kidney disfunction.

Cardiorenal interactions in acute decompensated heart failure: contemporary concepts facing emerging controversies

Simultaneous dysfunction of the heart and the kidney represents a distinct spectrum of disease states composed of complex clinical scenarios with adverse outcomes. Worsening renal function (WRF) in the setting of acute decompensated heart failure (ADHF) is one such clinical setup for which the underlying mechanisms are poorly understood. Apparent discrepancies exist between the emerging data on the cardiorenal interactions of patients with ADHF and contemporary concepts such as the low forward flow or the high backward pressure hypotheses. The findings of recent retrospective studies also suggest that apparent "improvement in renal function" might be yet another risk factor for untoward outcomes in this patient population, further challenging our current understanding of the cardiorenal interactions. Besides, these data do not seem to fully support our conventional thinking about other aspects of these interactions such as the independent adverse impact of WRF on the outcomes of patients with ADHF, pointing to congestion as a possibly overlooked factor. In this article, we provide an overview of these emerging controversial issues with the goal of identifying the areas where clinical research could be most helpful, because it is of paramount importance to characterize the pathways leading to WRF in ADHF to develop a mechanistically relevant management strategy. Although the paucity of data coupled with the complexity of this field precludes any firm conclusion, these discussions are meant to prompt clinicians and researchers to revisit a number of long-believed concepts surrounding the cardiorenal interactions in ADHF.

Diuretics associated acute kidney injury: clinical and pathological analysis

OBJECTIVE

In order to evaluate the clinical and pathological characteristics of diuretics associated acute kidney injury (AKI) and its management.

METHODS

We performed a retrospective study including 131 cases that diagnosed as diuretics associated AKI from 1 January 1999 to 1 January 2010 in Ruijin Hospital affiliated to Shanghai Jiao Tong University. Drug applications and its related clinical, laboratory and histological data were collected.

RESULTS

The male to female ratio was 2:1. The proportion of ages <20 years, 20-40 years, 40-60 years and ≥ 60 years were 6.9%, 17.6%, 27.5% and 48.1% respectively. Most patients (96.2%) had at least one complication of which chronic kidney disease (CKD) occurred most frequently (72 in 131, 55.0%). We divided all the patients to diuretic group (N=131) and non-diuretic group (N=185) based on diuretics history. We found patients in diuretic group had higher rates of CVD (38.9% vs. 18.4%), hypertension (42.0% vs. 29.2%), CKD (55.0% vs. 27.0%) and DM (17.6% vs. 4.3%) than non-diuretic group. Of 131 diuretics associated AKI, 36 cases (27.5%) were caused by diuretics only, 39 cases (29.8%) were caused by the combination of diuretics and other drugs like antibiotics, contrast media, ACEI or NSAIDs, and 56 cases (42.7%) had other AKI risk factors such as operation, infection, acute heart failure or hepatorenal syndrome. In addition, our data suggested the severity of RIFLE classification and pathological injury of glomerular basement membrane was higher in large-dosage furosemide group (>=120 mg/d) than in low-dosage group (<120 mg/d). The most common lesion induced by diuretics was vacuolar degeneration of tubular epithelial cell. Logistic regression analysis showed predictors of all-cause mortality were age, gender, RIFLE classification when AKI onset. Age and RIFLE classification were predictive factor of non-complete recovery.

CONCLUSION

This article firstly focuses on diuretics associated AKI, whose onset was related to aging, primary diseases and diuretic dosage. The combination of diuretics with other drugs such as antibiotics, contrast media, ACEI, NSAIDs, etc. would synergistically induced AKI. The pathological lesion of diuretics associated AKI may be mostly manifested vacuolar degeneration of tubular epithelial cell. Aging, gender, severity of RIFLE classification may be predictive factors of all-cause mortality of diuretics associated AKI.

Therapeutic potential of renal sympathetic denervation in patients with chronic heart failure

Chronic heart failure is associated with sympathetic activation characterised by elevated circulating norepinephrine levels linked to cardiovascular morbidity and mortality. Norepinephrine induces phenotype changes of the cardiomyocyte, fibrosis and β-adrenergic signal transduction defects implicated in the dysregulation of contractility. Renal denervation reduces left ventricular hypertrophy and improves diastolic dysfunction, partly blood pressure independently. Also, exercise tolerance and cardiac arrhythmias are positively influenced. Furthermore, there is evidence that common comorbidities like sleep apnoea, metabolic disease and microalbuminuria are improved following renal denervation. The available evidence suggests performing randomised controlled trials to scrutinise whether renal sympathetic denervation might be able to improve morbidity and mortality in chronic heart failure with preserved or reduced ejection fraction.

The role of albuminuria as a non-invasive marker for congestive acutely decompensated chronic heart failure and the spironolactone effect in elderly Portuguese: a non-randomized trial

BACKGROUND/OBJECTIVES

Albuminuria is a robust, validated cardiovascular risk factor. It is a simple and widely available test that was shown to be a powerful and independent predictor of prognosis in chronic heart failure. Mineralocorticoid receptor antagonists may reduce the acute and chronic harmful effects of mineralocorticoid receptor activation on the kidney. The objectives of the trial were to compare the effect of spironolactone versus standard acutely decompensated heart failure (ADHF) therapy on albuminuria and to investigate the role of albuminuria as a prognostic marker in patients with ADHF.

METHODS

Secondary analysis of a prospective, interventional study including 100 patients with ADHF. Fifty patients were non-randomly assigned to spironolactone 100 mg/day plus standard ADHF therapy (intervention group) or standard ADHF therapy alone (control group).

RESULTS

Patients in control group were older, had higher creatinine and urea levels, and had higher proportion of microalbuminuria (all, P < 0.05). Paired comparison of baseline and day 3 log albuminuria within each group, showed a more pronounced decrease in the intervention group (1.79 ± 0.75 to 1.59 ± 0.67, P = 0.003 vs 1.89 ± 0.70 to 1.79 ± 0.74, P = 0.096). In addition, the proportion of patients with normoalbuminuria increased from baseline to day 3 in spironolactone group (20 (40%) to 27 (54%), P < 001), accordingly the number of patients in the micro and macroalbuminuria groups was reduced. Day 1 albuminuria was positively correlated with day 1 N-terminal pro-brain natriuretic peptide (0.260 [0.105-0.758], P = 0.009).

CONCLUSIONS

High-dose spironolactone added to standard ADHF therapy is likely to induce a more pronounced albuminuria decrease and a significant reduction in the proportion of micro and macroalbuminuria.

The renal arterial resistance index: a marker of renal function with an independent and incremental role in predicting heart failure progression

AIMS

The renal arterial resistance index (RRI) is a measure of renal blood flow obtained by Doppler ultrasonography, which has been demonstrated to reflect both vascular and parenchymal renal abnormalities. The aim of the study was to evaluate clinical correlates and the prognostic relevance of RRI in a group of patients affected by chronic heart failure (CHF).

METHODS AND RESULTS

We enrolled 250 CHF outpatients in a stable clinical condition and receiving conventional therapy. Peak systolic velocity and end-diastolic velocity of a segmental renal artery were obtained by pulsed Doppler flow. Then the RRI was calculated. Standard renal function assessment was obtained by the measurement of creatinine serum levels and the estimation of the glomerular filtration rate (GFR). During follow-up (21.4 ± 11.3 months), 41 patients experienced heart failure progression (hospitalization and/or heart transplantation and/or death due to worsening heart failure). Considered as a continuous variable, RRI was associated with events at univariate [hazard ratio (HR) 1.14; 95% confidence interval (CI) 1.09-1.19; P < 0.001] as well as at multivariate Cox regression analysis (HR 1.08; 95% CI 1.02-1.13; P = 0.004) after correction for independent predictors of the reference model. When the RRI was added to the reference model including GFR, a significant improvement of reclassification according to both category-free net reclassification improvement (NRI, 47%; 95% CI 13-80%; P = 0.006) and integrated discrimination improvement (IDI, 0.034; 95% CI 0.006-0.061; P = 0.016) was observed.

CONCLUSIONS

Quantification of arterial renal perfusion provides a new parameter that independently predicts CHF patient outcome, thus strengthening its possible role in current clinical practice in order to better characterize renal function and stratify patients' prognosis.

Loop diuretics and ultrafiltration in heart failure

INTRODUCTION

Despite widespread use of loop diuretics in congestive heart failure (HF) to achieve decongestion and relief of symptoms, as recommended by the current guidelines, there is uncertainty as to their long-term therapeutic efficacy and safety. Their efficacy and safety compared to venous ultrafiltration are currently under investigation in acute decompensated HF patients.

AREAS COVERED

In this article, the authors review current available data related to efficacy and safety of loop diuretics and ultrafiltration in HF.

EXPERT OPINION

The literature review highlights an unmet clinical need for evidence-based algorithms, potentially using not only the classical clinical signs and symptoms of congestion as well as the estimated glomerular filtration rate and serum electrolytes, but also biomarkers of congestion/decongestion, neurohumoural activation or urinary kidney injury molecules, in order to optimize both loop diuretics and renin-angiotensin-aldosterone system blocker use in HF patients.

Renal sympathetic denervation: applications in hypertension and beyond

Renal afferent and efferent sympathetic nerves are involved in the regulation of blood pressure and have a pathophysiological role in hypertension. Renal sympathetic denervation is a novel therapeutic technique for the treatment of patients with resistant hypertension. Clinical trials of renal sympathetic denervation have shown significant reductions in blood pressure in these patients. Renal sympathetic denervation also reduces heart rate, which is a surrogate marker of cardiovascular risk. Conditions that are comorbid with hypertension, such as heart failure and myocardial hypertrophy, obstructive sleep apnoea, atrial fibrillation, renal dysfunction, and metabolic syndrome are closely associated with enhanced sympathetic activity. In experimental models and case-control studies, renal denervation has had beneficial effects on these conditions. Renal denervation could become a commonly used procedure to treat resistant hypertension and chronic diseases associated with enhanced sympathetic activation. Current work is focused on refining the techniques and interventional devices to provide safe and effective renal sympathetic denervation. Controlled studies in patients with mild-to-moderate, nonresistant hypertension and comorbid conditions such as heart failure, diabetes mellitus, sleep apnoea, and arrhythmias are needed to investigate the capability of renal sympathetic denervation to improve cardiovascular outcomes.