A re-appraisal of volume status and renal function impairment in chronic heart failure: combined effects of pre-renal failure and venous congestion on renal function

Potential Neuromodulation of the Cardio-Renal Syndrome

The cardio-renal syndrome (CRS) type 2 is defined as a progressive loss of renal function following a primary insult to the myocardium that may be either acute or chronic but is accompanied by a decline in myocardial pump performance. The treatment of patients with CRS is difficult, and the disease often progresses to end-stage renal disease that is refractory to conventional therapy. While a good deal of information is known concerning renal injury in the CRS, less is understood about how reflex control of renal sympathetic nerve activity affects this syndrome. In this review, we provide insight into the role of the renal nerves, both from the afferent or sensory side and from the efferent side, in mediating renal dysfunction in CRS. We discuss how interventions such as renal denervation and abrogation of systemic reflexes may be used to alleviate renal dysfunction in the setting of chronic heart failure. We specifically focus on a novel cardiac sensory reflex that is sensitized in heart failure and activates the sympathetic nervous system, especially outflow to the kidney. This so-called Cardiac Sympathetic Afferent Reflex (CSAR) can be ablated using the potent neurotoxin resinferitoxin due to the high expression of Transient Receptor Potential Vanilloid 1 (TRPV1) receptors. Following ablation of the CSAR, several markers of renal dysfunction are reversed in the post-myocardial infarction heart failure state. This review puts forth the novel idea of neuromodulation at the cardiac level in the treatment of CRS Type 2.

Hemoconcentration of Creatinine Minimally Contributes to Changes in Creatinine during the Treatment of Decompensated Heart Failure

Background

Worsening serum creatinine is common during treatment of acute decompensated heart failure (ADHF). A possible contributor to creatinine increase is diuresis-induced changes in volume of distribution (VD) of creatinine as total body water (TBW) contracts around a fixed mass of creatinine. Our objective was to better understand the filtration and nonfiltration factors driving change in creatinine during ADHF.

Methods

Participants in the ROSE-AHF trial with baseline to 72-hour serum creatinine; net fluid output; and urinary KIM-1, NGAL, and NAG were included (n=270). Changes in VD were calculated by accounting for measured input and outputs from weight-based calculated TBW. Changes in observed creatinine (Cr_observed) were compared with predicted changes in creatinine after accounting for alterations in VD and non-steady state conditions using a kinetic GFR equation (Cr_{72HR Kinetic}).

Results

When considering only change in VD, the median diuresis to elicit a ≥0.3 mg/dl rise in creatinine was -7526 ml (IQR, -5932 to -9149). After accounting for stable creatinine filtration during diuresis, a change in VD alone was insufficient to elicit a ≥0.3 mg/dl rise in creatinine. Larger estimated decreases in VD were paradoxically associated with improvement in Cr_observed (r=-0.18, P=0.003). Overall, -3% of the change in eCr_{72HR Kinetic} was attributable to the change in VD. A ≥0.3 mg/dl rise in eCr_{72HR Kinetic} was not associated with worsening of KIM-1, NGAL, NAG, or postdischarge survival (P>0.05 for all).

Conclusions

During ADHF therapy, increases in serum creatinine are driven predominantly by changes in filtration, with minimal contribution from change in VD.

Different Renal Function Patterns in Patients With Acute Heart Failure: Relationship With Outcome and Congestion

Background

The role of worsening renal function during acute heart failure (AHF) hospitalization is still debated. Very few studies have extensively evaluated the renal function (RF) trend during hospitalization by repetitive measurements.

Objectives

To investigate the prognostic relevance of different RF trajectories together with the congestion status in hospitalized patients.

Methods

This is a post hoc analysis of a multi-center study including 467 patients admitted with AHF who were screened for the Diur-AHF Trial. We recognized five main RF trajectories based on serum creatinine and estimated glomerular filtration rate (eGFR) behavior. According to the RF trajectories our sample was divided into 1-stable (S), 2-transient improvement (TI), 3-permanent improvement (PI), 4-transient worsening (TW), and 5-persistent worsening (PW). The primary outcome was the combined endpoint of 180 days including all causes of mortality and re-hospitalization.

Results

We recruited 467 subjects with a mean congestion score of 3.5±1.08 and a median creatinine value of 1.28 (1.00-1.70) mg/dl, eGFR 50 (37-65) ml/min/m2 and NTpro B-type natriuretic peptide (BNP) 7,000 (4,200-11,700) pg/ml. A univariate analysis of the RF pattern demonstrated that TI and PW patterns were significantly related to poor prognosis [HR: 2.71 (1.81-4.05); p < 0.001; HR: 1.68 (1.15-2.45); p = 0.007, respectively]. Conversely, the TW pattern showed a significantly protective effect on outcome [HR:0.34 (0.19-0.60); p < 0.001]. Persistence of congestion and BNP reduction ≥ 30% were significantly related to clinical outcome at univariate analysis [HR: 2.41 (1.81-3.21); p < 0.001 and HR:0.47 (0.35-0.67); p < 0.001]. A multivariable analysis confirmed the independently prognostic role of TI, PW patterns, persistence of congestion, and reduced BNP decrease at discharge.

Conclusions

Various RF patterns during AHF hospitalization are associated with different risk(s). PW and TI appear to be the two trajectories related to worse outcome. Current findings confirm the importance of RF evaluation during and after hospitalization.

Effect of aggressive diuresis in acute heart failure with reduced and preserved ejection fraction

Aims

Heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF) had distinct haemodynamic characteristics in the setting of acute heart failure. The aim of our study is to evaluate the differential response to aggressive diuresis in HFrEF and HFpEF.

Methods and results

Patients in the Diuretic Optimization Strategies Evaluation trial with left ventricular ejection fraction measurement were included (n = 300) and classified into HFrEF [left ventricular ejection fraction (LVEF) < 40%] (n = 193) and HFpEF (LVEF ≥ 40%) (n = 107). Effect of high‐dose vs. low‐dose furosemide strategy was compared separately in HFrEF and HFpEF. In HFrEF, high‐dose strategy did not increase change in creatinine or cystatin C at 72 h [treatment difference: −0.05, 95% confidence interval (CI): −0.14 to 0.03 mg/dL; P = 0.23 for creatinine, and treatment difference: −0.06, 95% CI: −0.15 to 0.02 mg/dL; P = 0.15 for cystatin C] compared with low‐dose strategy, but there were significantly more net fluid loss, weight loss, and congestion‐free patients at 72 h in high‐dose group. It was also associated with a significantly lower risk of composite clinical outcome of death, total hospitalizations, and unscheduled visits due to heart failure. In HFpEF, high‐dose strategy significantly increased change in creatinine and cystatin C at 72 h (treatment difference: 0.16; 95% CI: 0.02–0.30 mg/dL; P = 0.03 for creatinine, and treatment difference: 0.26; 95% CI: 0.09–0.43 mg/dL; P = 0.003 for cystatin C), but did not significantly affect net fluid loss, weight loss, proportion of congestion‐free patients at 72 h, and risk of the composite clinical outcome.

Conclusions

Acute heart failure on the basis of HFrEF and HFpEF responded differently to aggressive diuresis. Future trials should be designed separately for HFrEF and HFpEF.

Arginine Vasopressin as an Important Mediator of Fluctuations in the Serum Creatinine Concentration Under Decongestion Treatment in Heart Failure Patients

Background: The mechanism underlying serum creatinine (SCr) fluctuations in heart failure (HF) patients remains unclear. This study examined mediators of SCr fluctuations under diuretic treatment in HF patients.

Methods and Results: Data from 26 HF patients were analyzed. Clinical tests included measurement of peripheral blood, blood urea nitrogen, SCr, serum and urinary electrolytes, B-type natriuretic peptide (BNP), and plasma neurohormones. Among the 26 patients recovering from worsening HF, changes in SCr were negatively correlated with changes in serum Cl, and positively correlated with changes in plasma arginine vasopressin (AVP). According to the median change in SCr, patients were divided into high (range 0.16–0.79 mg/dL; n=13) and low (range −0.35 to 0.14 mg/dL; n=13) change groups. Plasma AVP concentrations after treatment decreased in the low SCr change group and increased in the high SCr change group (−1.28±2.8 vs. 2.14±4.4 pg/mL, respectively; P=0.027). In both groups, there was no change in plasma volume, plasma BNP and norepinephrine concentrations decreased, and plasma renin activity increased after treatment. Multivariate logistic regression analysis showed a tendency towards an independent association between an increase in SCr and an increase or no change in the plasma AVP after decongestion (odds ratio 4.44; 95% confidence interval 0.81–24.3; P=0.086).

Conclusions: Plasma AVP appears to be a physiologically important mediator of SCr fluctuations under decongestion treatment in HF patients.

Renal dysfunction in cardiovascular diseases and its consequences

It is well known that the heart and kidney and their synergy is essential for hemodynamic homeostasis. Since the early XIX century it has been recognized that cardiovascular and renal diseases frequently coexist. In the nephrological field, while it is well accepted that renal diseases favor the occurrence of cardiovascular diseases, it is not always realized that cardiovascular diseases induce or aggravate renal dysfunctions, in this way further deteriorating cardiac function and creating a vicious circle. In the same clinical field, the role of venous congestion in the pathogenesis of renal dysfunction is at times overlooked. This review carefully quantifies the prevalence of chronic and acute kidney abnormalities in cardiovascular diseases, mainly heart failure, regardless of ejection fraction, and the consequences of renal abnormalities on both organs, making cardiovascular diseases a major risk factor for kidney diseases. In addition, with regard to pathophysiological aspects, we attempt to substantiate the major role of fluid overload and venous congestion, including renal venous hypertension, in the pathogenesis of acute and chronic renal dysfunction occurring in heart failure. Furthermore, we describe therapeutic principles to counteract the major pathophysiological abnormalities in heart failure complicated by renal dysfunction. Finally, we underline that the mild transient worsening of renal function after decongestive therapy is not usually associated with adverse prognosis. Accordingly, the coexistence of cardiovascular and renal diseases inevitably means mediating between preserving renal function and improving cardiac activity to reach a better outcome.

Congestion occurrence and evaluation in acute heart failure scenario: time to reconsider different pathways of volume overload

Although congestion is considered to be the main reason for hospital admission in patients with acute heart failure, a simplistic view considering idro saline retention and total body volume accumulation did not provide convincing data. Clinical congestion occurrence is often the tip of the iceberg of several different mechanisms ranging from increased filling pressure to extravascular fluid accumulation and blood flow redistribution. Therefore, the clinical evaluation is often restricted to a simple physical examination including few and inaccurate signs and symptoms. This superficial approach has led to contradictory data and patients have not been evaluated according to a more realistic clinical scenario. The integration with new diagnostic ultrasonographic and laboratory tools would substantially improve these weaknesses. Indeed, congestion could be assessed by following the most recognized HF subtypes including primitive cardiac defect, presence of right ventricular dysfunction, and organ perfusion. Moreover, there is a tremendous gap regarding the interchangeable concept of fluid retention and redistribution used with a univocal meaning. Overall, congestion assessment should be revised, considering it as either central, peripheral, or both. In this review, we aim to provide different evidence regarding the concept of congestion starting from the most recognized pathophysiological mechanisms of AHF decompensation. We highlight the fact that a better knowledge of congestion is a challenge for future investigation and it could lead to significant advances in HF treatment.

Renal venous congestion following hemorrhagic shock due to traumatic liver injury

A 78-year-old woman who sustained traumatic liver injury with hemorrhagic shock was hospitalized. She was admitted to the ICU after blood transfusion and emergent angiography. AKI was observed on the following day. Blood transfusion was continued because initial assessment was prerenal AKI due to hypovolemia. Despite transfusion of blood products and administration of diuretics, aggravated renal dysfunction, and low urine output continued, resulting in respiratory failure due to pulmonary edema. Renal venous congestion was suspected as the primary cause of AKI, since IVC compression from a hematoma with IVC injury was observed on CT imaging captured on admission, and renal Doppler ultrasonography demonstrated an intermittent biphasic pattern of renal venous flow. It was finally concluded that renal venous congestion resulted from IVC compression, since urine output increased remarkably after RRT without additional diuretics, and follow-up CT and renal Doppler ultrasonography revealed improvements in IVC compression and renal venous flow pattern, respectively. Renal venous congestion has been often reported to be associated with acute decompensated heart failure and, to our knowledge, this is the first report to describe trauma-induced renal venous congestion. Trauma patients are at risk for renal venous congestion due to massive blood transfusion after recovery from hemorrhagic shock; therefore, if they develop AKI that cannot be explained by other etiologies, physicians should consider the possibility of trauma-induced renal venous congestion and perform renal Doppler ultrasonography.

Effects of Sodium-Glucose Co-transporter 2 Inhibition with Empaglifozin on Renal Structure and Function in Non-diabetic Rats with Left Ventricular Dysfunction After Myocardial Infarction

Background

The use of sodium–glucose co-transporter 2 inhibitors (SGLT2i) is currently expanding to cardiovascular risk reduction in non-diabetic subjects, but renal (side-)effects are less well studied in this setting.

Methods

Male non-diabetic Sprague Dawley rats underwent permanent coronary artery ligation to induce MI, or sham surgery. Rats received chow containing empagliflozin (EMPA) (30 mg/kg/day) or control chow. Renal function and electrolyte balance were measured in metabolic cages. Histological and molecular markers of kidney injury, parameters of phosphate homeostasis and bone resorption were also assessed.

Results

EMPA resulted in a twofold increase in diuresis, without evidence for plasma volume contraction or impediments in renal function in both sham and MI animals. EMPA increased plasma magnesium levels, while the levels of glucose and other major electrolytes were comparable among the groups. Urinary protein excretion was similar in all treatment groups and no histomorphological alterations were identified in the kidney. Accordingly, molecular markers for cellular injury, fibrosis, inflammation and oxidative stress in renal tissue were comparable between groups. EMPA resulted in a slight increase in circulating phosphate and PTH levels without activating FGF23–Klotho axis in the kidney and bone mineral resorption, measured with CTX-1, was not increased.

Conclusions

EMPA exerts profound diuretic effects without compromising renal structure and function or causing significant electrolyte imbalance in a non-diabetic setting. The slight increase in circulating phosphate and PTH after EMPA treatment was not associated with evidence for increased bone mineral resorption suggesting that EMPA does not affect bone health.

Electronic supplementary material

The online version of this article (10.1007/s10557-020-06954-6) contains supplementary material, which is available to authorized users.

Spironolactone metabolite concentrations in decompensated heart failure: insights from the ATHENA-HF trial

AIMS

In Aldosterone Targeted Neurohormonal Combined with Natriuresis Therapy in Heart Failure (ATHENA-HF), high-dose spironolactone (100 mg daily) did not improve efficacy endpoints over usual care [placebo or continued low-dose spironolactone (25 mg daily) in patients already receiving spironolactone] in the treatment of acute heart failure (HF). We hypothesized that low concentrations of the long-acting active metabolites of spironolactone [canrenone and 7α-thiomethylspironolactone (7α-TMS)] in the high-dose group could have contributed to these neutral results.

METHODS AND RESULTS

In patients randomized to high-dose spironolactone not previously treated with spironolactone (high-dose-naïve, n = 112), concentrations of canrenone and 7α-TMS increased at 48 and 96 h compared to baseline, and between 48 and 96 h (all P < 0.005), indicating that steady-state concentrations had not been reached by 48 h. In patients previously on low-dose, high-dose spironolactone (high-dose-previous, n = 37), concentrations of canrenone increased at 48 and 96 h compared to baseline (both P < 0.0005), with a marginal increase between 48 and 96 h (P = 0.0507). At 48 h, both high-dose groups had higher concentrations of both metabolites than the low-dose spironolactone group (P < 0.0001). Moreover, concentrations of both metabolites were higher in high-dose-previous vs. high-dose-naïve patients (P < 0.01), indicating that previous spironolactone use was significant, and that steady-state has not been reached in high-dose-naïve patients at 48 h. We found limited and inconsistent evidence of correlation between metabolite concentrations and endpoints.

CONCLUSIONS

Lower-than-anticipated concentrations of spironolactone active metabolites were observed for at least 48 h in the high-dose spironolactone group and may have contributed to the absence of pharmacological effects of spironolactone in the ATHENA-HF trial.

Serum creatinine trajectories in real-world hospitalized patients: clinical context and short-term mortality

Fluctuations in serum creatinine (SCr) during hospitalization may provide additional prognostic value beyond baseline renal function. This study aimed to identify groups of patients with distinct creatinine trajectories over hospital stay and assess them in terms of clinical characteristics and short-term mortality. This retrospective study included 35 853 unique adult admissions to a tertiary referral center between January 2012 and January 2016 with at least three SCr measurements within the first 9 days of stay. Individual SCr courses were determined using linear regression or linear-splines model and grouped into clusters. SCr trajectories were described as median SCr courses within clusters. Almost half of the patients presented with changing, mainly declining SCr concentration during hospitalization. In comparison to patients with an increase in SCr, those with a significant decline were younger, more often admitted via the emergency department, more often required a higher level of care, had fewer comorbidities and the more pronounced the fall in SCr, the greater the observed difference. Regardless of baseline renal function, an increase in SCr was related to the highest in-hospital mortality risk among compared clusters. Also, patients with normal renal function at admission followed by decreasing SCr were at higher risk of inpatient death, but lower 90-day postdischarge mortality than patients with a stable SCr. Acute changes in inpatient SCr convey important prognostic information and can only be interpreted by looking at their evolution over time. Recognizing underlying causes and providing adequate care is crucial for improving adverse prognosis.

The impact of kidney dysfunction categorized by urinary to serum creatinine ratio on clinical outcomes in patients with heart failure

Kidney dysfunction (KD) is closely associated with poor clinical outcome in patients with heart failure (HF). KD is classified as intrinsic and pre-renal KD. However, the impact of each KD on the clinical outcome in patients with HF has not yet been fully elucidated. We measured the urinary to serum creatinine (UC/SC) ratio, a marker for intrinsic and pre-renal KD, in 1009 consecutive patients with HF at admission. There were 314 cardio-renal events including HF and advanced end-stage renal dysfunction during the median follow-up period of 1154 days. There were 63 (6%) patients with intrinsic KD (UC/SC ratio < 20), 118 (12%) patients with intermediate KD (UC/SC ratio 20-40), 607 (60%) patients with pre-renal KD (UC/SC ratio > 40), and 221 (22%) patients with no KD. Multivariate Cox's proportional hazard regression analysis demonstrated that intrinsic and intermediate KDs were significantly associated with poor clinical outcome. The prediction model for cardio-renal events was significantly improved by the addition of UC/SC ratio to the confounding risk factors. Subgroup analysis in patients with HF with severely reduced glomerular filtration rates showed that the prevalence rates of intrinsic, intermediate, and pre-renal KDs were 23%, 30%, and 47%, respectively. The cardio-renal event rate was the highest in the intrinsic KD group compared with that in the other groups. Intrinsic KD was closely associated with extremely poor clinical outcome in patients with HF. The UC/SC ratio could provide important clinical information for the treatment and management of KD in patients with HF.

Implication of Acute Kidney Injury in Heart Failure

Patients with acute or chronic decompensated heart failure (ADHF) present with various degrees of heart and kidney dysfunction characterizing cardiorenal syndrome (CRS). CRS can be generally defined as a pathophysiologic disorder of the heart and kidneys whereby acute or chronic dysfunction of 1 organ may induce acute or chronic dysfunction of the other. ADHF is a challenge in the management of heart failure. This review provides an overview the pathophysiology of type 1 CRS together with new approaches to treatment in patients with heart failure with worsening renal function or acute kidney disease.

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.

Negotiating renal dysfunction when treating patients with heart failure

INTRODUCTION

Chronic kidney disease (CKD) is one of the most prevalent comorbidities in HF, and no specific treatment is still available for the so-called cardiorenal syndrome. Areas covered: The aim of this review is to describe the interaction of heart and kidney function and the consequences of cardiorenal syndrome, focusing on the use of available therapeutics. Expert commentary: The presence of CKD has been associated with adverse outcomes in HF regardless of ejection fraction. On the other hand, cardiovascular events are the most common causes of morbidity and mortality among CKD patients, reflecting the close pathophysiological crosstalk between these organs. Multiple mechanisms are involved in the development of cardiorenal syndrome, including hemodynamic, neurohormonal and inflammatory mediators. The management of several HF drugs is a challenge in the presence of CKD mainly due to blunted diuretic response and increased risk of worsening of kidney function. Therefore, finding a balance between the optimization of cardiac and renal outcomes is a real negotiation in the everyday clinical practice.

Ultrasonic evaluation of renal cortex arterial area enables differentiation between hypertensive and glomerulonephritis-related chronic kidney disease

PURPOSE

Identifying the primary etiology of cardio-renal syndrome in a timely manner remains an ongoing challenge in nephrology. We hypothesized that hypertensive kidney damage can be distinguished from chronic glomerulonephritis at an early stage of chronic kidney disease (CKD) using ultrasound (US) Doppler sonography.

METHODS

Fifty-six males (age 54 ± 15, BMI 28.3 ± 3.5 kg/m2) with hypertension and stable CKD at stages 2-4 [38 with essential hypertension (HT-CKD); 18 with glomerulonephritis (GN-CKD)] were studied. Blood tests, UACR, echocardiography, ABPM, carotid IMT, and an ultrasound dynamic tissue perfusion measurement (DTPM) of the renal cortex were performed.

RESULTS

HT-CKD patients had reduced proximal renal cortex perfusion as well as reduced total and proximal renal cortex arterial area. Proximal renal cortex arterial area ≤0.149 cm2 identified hypertension-related CKD with a sensitivity of 71% and a specificity of 78% (AUC 0.753, p < 0.001).

CONCLUSIONS

Evidence of diminished arterial vascularity or perfusion of renal proximal cortex, both derived from US Doppler, could be helpful in differentiating hypertensive nephropathy from glomerulonephritis-related CKD.

[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.

Blood urea nitrogen to creatinine ratio is associated with congestion and mortality in heart failure patients with renal dysfunction

Renal dysfunction (RD) and venous congestion are related and common in heart failure (HF). Studies suggest that venous congestion may be the primary driver of RD in HF. In this study, we sought to investigate retrospectively the relationship between common measures of renal function with caval congestion and mortality among outpatients with HF and RD. We reviewed data from 103 HF outpatients (45 males, mean age 74 years, ejection fraction 41.8 ± 11.6 %) with estimated glomerular filtration rate (eGFR) of < 60 ml/min in a single centre. During an ambulatory visit, all patients underwent blood test and ultrasonography of the inferior vena cava (IVC). Caval congestion was defined as IVC with both dilatation and impaired collapsibility. The best values of renal metrics in predicting caval congestion were determined with receiver-operating characteristic analysis. The BUN/Cr ratio is moderately correlated with IVC expiratory maximum diameter (r = 0.31, p < 0.0007). In a multiple logistic regression model, BUN/Cr > 25.5 (adjusted OR 2.98, p 0.015) and eGFR ≤ 45.8 (adjusted OR 5.38, p 0.002) identify patients at risk for caval congestion; a BUN/Cr > 23.7 was the best predictor of impaired collapsibility (adjusted OR 4.41, p 0.001). a BUN/Cr > 25.5 (HR 2.19, 95 % CI 1.21-3.94, p < 0.001) and NYHA class 3 (HR 2.91, 95 % CI 1.60-5.31, p < 0.0005) were independent risk factors associated with all-cause death during a median follow-up of 31 months. In outpatients with HF and RD, a higher BUN/Cr and lower eGFR are reliable renal biomarkers for caval congestion. The BUN/Cr is associated with long-term mortality and may help to stratify HF severity.

Characterization of a murine model of cardiorenal syndrome type 1 by high-resolution Doppler sonography

ABSTRACT

Cardiorenal syndrome type 1 (CRS-1) is the acute kidney disfunction caused by an acute worsening of cardiac function. CRS-1 is the consequence of renal vasoconstriction secondary to renin-angiotensin system (RAS) activation. No animal models of CRS-1 are described in literature.

PURPOSE

To characterize a murine model of CRS-1 by using a high-resolution ultrasound echo-color Doppler system (VEVO2100).

MATERIALS

Post-ischemic heart failure was induced by coronary artery ligation (LAD) in seven CD1 mice. Fifteen and thirty days after surgery, mice underwent cardiac and renal echo-color Doppler. Serum creatinine and plasma renin activity were measured after killing. Animals were compared to seven CD1 control mice.

RESULTS

Heart failure with left ventricle dilatation (end diastolic area, p < 0.05 vs. controls) and significantly reduced ejection fraction (EF; p < 0.01 vs. controls) was evident 15 days after LAD. We measured a significant renal vasoconstriction in infarcted mice characterized by increased renal pulsatility index (PI; p < 0.05 vs. controls) associated to increased creatinine and renin levels (p < 0.05 vs. controls).

CONCLUSIONS

The mice model of LAD is a good model of CRS-1 evaluable by Doppler sonography and characterized by renal vasoconstriction due to the activation of the renin-angiotensin system secondary to heart failure.

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.

Renal perfusion index reflects cardiac systolic function in chronic cardio-renal syndrome

BACKGROUND

Cardiac dysfunction can modify renal perfusion, which is crucial to maintain sufficient kidney tissue oxygenation. Renal cortex perfusion assessed by dynamic ultrasound method is related both to renal function and cardiac hemodynamics. The aim of the study was to test the hypothesis that Renal Perfusion Index (RPI) can more closely reflect cardiac hemodynamics and differentiate etiology of chronic cardio-renal syndrome.

MATERIAL AND METHODS

Twenty-four patients with hypertension and chronic kidney disease (CKD) at 2-4 stage (12 with hypertensive nephropathy and 12 with CKD prior to hypertension) were enrolled in the study. Blood tests, 24-h ABPM, echocardiography, and ultrasonography with estimation of Total renal Cortical Perfusion intensity and Renal Perfusion Index (RPI) were performed.

RESULTS

In the group of all patients, RPI correlated with left ventricular stoke volume (LVSV), and cardiac index, but not with markers of renal function. In multiple stepwise regression analysis CKD-EPI(Cys-Cr) (b=-0.360), LVSV (b=0.924) and MAP (b=0.376) together independently influenced RPI (R2=0.74; p<0.0001). RPI<0.567 allowed for the identification of patients with chronic cardio-renal syndrome with sensitivity of 41.7% and specificity of 83.3%.

CONCLUSIONS

Renal perfusion index relates more strongly to cardiac output than to renal function, and could be helpful in recognizing chronic cardio-renal syndrome. Applicability of RPI in diagnosing early abnormalities in the cardio-renal axis requires further investigation.

A gender based analysis of predictors of all cause death after transcatheter aortic valve implantation

The impact of gender-related pathophysiologic features of severe aortic stenosis on transcatheter aortic valve implantation (TAVI) outcomes remains to be determined, as does the consistency of predictors of mortality between the genders. All consecutive patients who underwent TAVI at 6 institutions were enrolled in this study and stratified according to gender. Midterm all-cause mortality was the primary end point, with events at 30 days and at midterm as secondary end points. All events were adjudicated according to Valve Academic Research Consortium definitions. Eight hundred thirty-six patients were enrolled, 464 (55.5%) of whom were female. At midterm follow-up (median 365 days, interquartile range 100 to 516) women had similar rates of all-cause mortality compared with men (18.1% vs 22.6%, p = 0.11) and similar incidence of myocardial infarction and cerebrovascular accident. Gender did not affect mortality also on multivariate analysis. Among clinical and procedural features, glomerular filtration rate <30 ml/min/1.73 m(2) (hazard ratio [HR] 2.55, 95% confidence interval [CI] 1.36 to 4.79) and systolic pulmonary arterial pressure >50 mm Hg (HR 2.26, 95% CI 1.26 to 4.02) independently predicted mortality in women, while insulin-treated diabetes (HR 3.45, 95% CI 1.47 to 8.09), previous stroke (HR 3.42, 95% CI 1.43 to 8.18), and an ejection fraction <30% (HR 3.82, 95% CI 1.41 to 10.37) were related to mortality in men. Postprocedural aortic regurgitation was independently related to midterm mortality in the 2 groups (HR 11.19, 95% CI 3.3 to 37.9). In conclusion, women and men had the same life expectancy after TAVI, but different predictors of adverse events stratified by gender were demonstrated. These findings underline the importance of a gender-tailored clinical risk assessment in TAVI patients.

The cardiorenal syndrome in heart failure: cardiac? renal? syndrome?

There has been increasing interest on the so-called cardiorenal syndrome (CRS), defined as a complex pathophysiological disorder of the heart and kidneys whereby acute or chronic dysfunction in one organ may induce acute or chronic dysfunction in the other. In this review, we contend that there is lack of evidence warranting the adoption of a specific clinical construct such as the CRS within the heart failure (HF) syndrome by demonstrating that: (a) the approaches and tools regarding the definition of kidney involvement in HF are suboptimal; (b) development of renal failure in HF is often confounded by age, hypertension, and diabetes; (c) worsening of renal function (WRF) in HF may be largely independent of alterations in cardiac function; (d) the bidirectional association between HF and renal failure is not unique and represents one of the several such associations encountered in HF; and (e) inflammation is a common denominator for HF and associated noncardiac morbidities. Based on these arguments, we believe that dissecting one of the multiple bidirectional associations in HF and constructing the so-called cardiorenal syndrome is not justified pathophysiologically. Fully understanding of all morbid associations and not only the cardiorenal is of great significance for the clinician who is caring for the patient with HF.

The puzzle of kidney dysfunction in heart failure: an introduction

Heart failure and kidney disease often coexist, and each of the two conditions may lead to progression of the other. Kidney dysfunction is an independent prognostic factor in patients with either acute or chronic heart failure. Worsening renal function may be related with poorer outcomes as well. Multiple mechanisms are involved in the cardio-renal interaction, including hemodynamic abnormalities, neurohormonal and inflammatory activation, oxidative stress, anemia, and abnormalities in mineral and vitamin D metabolism. Serum creatinine has limitations for the assessment of kidney function in patients with heart failure as its short-term changes are dependent on hemodynamic changes and fluid status. New biomarkers of glomerular and tubular function might allow an earlier and more accurate detection of worsening renal function.