ADQI 7: the clinical management of the Cardio-Renal syndromes: work group statements from the 7th ADQI consensus conference

Cardiac and Renal Fibrosis, the Silent Killer in the Cardiovascular Continuum: An Up-to-Date

Cardiovascular disease (CVD) and chronic kidney disease (CKD) often coexist and have a major impact on patient prognosis. Organ fibrosis plays a significant role in the pathogenesis of cardio-renal syndrome (CRS), explaining the high incidence of heart failure and sudden cardiac death in these patients. Various mediators and mechanisms have been proposed as contributors to the alteration of fibroblasts and collagen turnover, varying from hemodynamic changes to the activation of the renin-angiotensin system, involvement of FGF 23, and Klotho protein or collagen deposition. A better understanding of all the mechanisms involved has prompted the search for alternative therapeutic targets, such as novel inhibitors of the renin-angiotensin-aldosterone system (RAAS), serelaxin, and neutralizing interleukin-11 (IL-11) antibodies. This review focuses on the molecular mechanisms of cardiac and renal fibrosis in the CKD and heart failure (HF) population and highlights the therapeutic alternatives designed to target the responsible pathways.

Mitochondrial Impairment: A Link for Inflammatory Responses Activation in the Cardiorenal Syndrome Type 4

Cardiorenal syndrome type 4 (CRS type 4) occurs when chronic kidney disease (CKD) leads to cardiovascular damage, resulting in high morbidity and mortality rates. Mitochondria, vital organelles responsible for essential cellular functions, can become dysfunctional in CKD. This dysfunction can trigger inflammatory responses in distant organs by releasing Damage-associated molecular patterns (DAMPs). These DAMPs are recognized by immune receptors within cells, including Toll-like receptors (TLR) like TLR2, TLR4, and TLR9, the nucleotide-binding domain, leucine-rich-containing family pyrin domain-containing-3 (NLRP3) inflammasome, and the cyclic guanosine monophosphate (cGMP)-adenosine monophosphate (AMP) synthase (cGAS)-stimulator of interferon genes (cGAS-STING) pathway. Activation of these immune receptors leads to the increased expression of cytokines and chemokines. Excessive chemokine stimulation results in the recruitment of inflammatory cells into tissues, causing chronic damage. Experimental studies have demonstrated that chemokines are upregulated in the heart during CKD, contributing to CRS type 4. Conversely, chemokine inhibitors have been shown to reduce chronic inflammation and prevent cardiorenal impairment. However, the molecular connection between mitochondrial DAMPs and inflammatory pathways responsible for chemokine overactivation in CRS type 4 has not been explored. In this review, we delve into mechanistic insights and discuss how various mitochondrial DAMPs released by the kidney during CKD can activate TLRs, NLRP3, and cGAS-STING immune pathways in the heart. This activation leads to the upregulation of chemokines, ultimately culminating in the establishment of CRS type 4. Furthermore, we propose using chemokine inhibitors as potential strategies for preventing CRS type 4.

Prognostic value of estimated plasma volume in patients with chronic systolic heart failure

Assessing congestion is challenging but important to patients with chronic heart failure (CHF). However, there are limited data regarding the association between estimated plasma volume status (ePVS) determined using hemoglobin/hematocrit data and outcomes in patients with stable CHF. We prospectively analyzed 231 patients; the median follow-up period was 35.6 months. We calculated ePVS at admission using the Duarte and Strauss formula, derived from hemoglobin and hematocrit ratios and divided patients into three groups. The primary outcome was a composite of all-cause mortality or heart failure rehospitalization. Among 274 patients (61.98 years of age, 2.3% male), the mean ePVS was 3.98±0.90 dL/g. The third ePVS tertile had a higher proportion of primary outcome (71.4%) than the first or second tertile (48.1% and 59.7%, respectively; p=0.013). On multivariable Cox analysis, after adjusting for potential confounders, higher ePVS remained significantly associated with increased rate of primary outcome (adjusted HR 1.567, 95% CI 1.267 to 1.936; p<0.001). Kaplan-Meier survival analyses showed that the occurrence of primary outcome, all-cause mortality and rehospitalization increased progressively from first to third tertiles (p=0.006, 0.014 and 0.001; respectively). In receiver operating characteristic analysis, the area under the curve of ePVS for primary outcome was 0.645. ePVS determined using hemoglobin and hematocrit was independently associated with clinical outcomes for patients with stable CHF. Our study thus further strengthens the evidence that ePVS has important prognostic value in patients with stable CHF.

Trial registration number ChiCTR-ONC-14004463.

Urine Cofilin-1 Detection for Predicting Type 1 Cardiorenal Syndrome in the Coronary Care Unit: A Gold Nanoparticle- and Laser-Based Approach

BACKGROUND

Type 1 cardiorenal syndrome (CRS) is a severe complication for acute decompensated heart failure patients. This study aimed at evaluating the feasibility of using the gold nanoparticle-based localized surface plasmon-coupled fluorescence biosensor (LSPCFB) to detect urine cofilin-1 as a biomarker for predicting CRS among patients in the coronary care unit (CCU).

METHODS

A total of 44 patients were included with prospectively collected urine and blood samples. Both LSPCFB and conventional enzyme-linked immunosorbent assays (ELISAs) were used to measure urine cofilin-1 at admission to the CCU. The occurrence of CRS was judged within 7 days after admission. The discrimination presented as the area under the receiver operating characteristic curve (AUROC) and calibration of both detection methods were used to assess the predictive ability of urine cofilin-1 measured by the LSPCFB and ELISA.

RESULTS

Thirteen patients were diagnosed with CRS, while the other 31 patients were classified into a non-CRS group. For predicting CRS by measuring urine cofilin-1, the LSPCFB had higher accuracy (AUROC: 0.707, p = 0.031; overall accuracy: 79.55%) than the ELISA (AUROC: 0.479, p = 0.827; overall accuracy: 53.27%). The positive and negative predictive values of the LSPCFB were also higher than those of the ELISA (positive predictive value: 70.0 vs. 34.8%; negative predictive value: 82.4 vs. 76.2%).

CONCLUSIONS

The gold nanoparticle-based immunoassay LSPCFB could exploit the potential of urine cofilin-1 as a single biomarker to predict CRS among CCU patients.

Type 4 cardiorenal syndrome

The Acute Dialysis Quality Initiative consensus conference proposed a classification of cardiorenal syndrome (CRS), aiming for a better delineation of each subtype. Although the exact pathophysiology of type 4 CRS is not completely understood, the mechanisms involved are probably multifactorial. There is growing evidence that oxidative stress is a major connector in the development and progression of type 4 CRS. Giving its complexity, poor prognosis and increasing incidence, type 4 CRS is becoming a significant public health problem. Patients with chronic kidney disease are particularly predisposed to cardiac dysfunction, due to the high prevalence of traditional cardiovascular risk factors in this population, but the contribution of risk factors specific to chronic kidney disease should also be taken into account. Much remains to be elucidated about type 4 CRS: despite progress over the last decade, there are still significant questions regarding its pathophysiology and there is as yet no specific therapy. A better understanding of the mechanisms involved may provide potential targets for intervention. The present review will provide a brief description of the definition, epidemiology, diagnosis, prognosis, biomarkers and management strategies of type 4 CRS, and the pathophysiological mechanisms and risk factors presumably involved in its development will be particularly highlighted.

Peritoneal Dialysis for Heart Failure

Heart failure (HF) is a common and important cause of morbidity and mortality in the elderly, imposing a significant burden on healthcare systems. Better management of ischemic heart disease has resulted in increased survival and growth in the number of prevalent heart failure patients, but co-existing renal impairment complicates management and limits traditional therapeutic options. Ultrafiltration (UF) techniques have shown promise in the treatment of diuretic-resistant HF, but the early successes of extracorporeal treatments has not been confirmed by randomized trials. Peritoneal dialysis (PD) may be cheaper and provide more effective UF therapy in selected patients and this review examines the issues surrounding the use of PD for such patients. Whist many nephrologists are enthusiastic about the use of this technique, making a more cogent case for PD in this setting for cardiologists is likely to need a combined strategy of demonstrating improvement in individual cases and further study of potential medicoeconomic benefits.

The impact of intravenous ferric carboxymaltose on renal function: an analysis of the FAIR-HF study

AIMS

Anaemia and iron deficiency are constituents of the cardio-renal syndrome in chronic heart failure (CHF). We investigated the effects of i.v. iron in iron-deficient CHF patients on renal function, and the efficacy and safety of this therapy in patients with renal dysfunction.

METHODS AND RESULTS

The FAIR-HF trial randomized 459 CHF patients with iron deficiency (ferritin <100 µg/L, or between 100 and 299 µg/L if transferrin saturation was <20%): 304 to i.v. ferric carboxymaltose (FCM) and 155 to placebo, and followed-up for 24 weeks. Renal function was assessed at baseline and at weeks 4, 12, and 24, using the estimated glomerular filtration rate (eGFR, mL/min/1.73 m(2) ), calculated from the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula. At baseline, renal function was similar between groups (62.4 ± 20.6 vs. 62.9 ± 23.4 mL/min/1.73 m(2) , FCM vs. placebo). Compared with placebo, treatment with FCM was associated with an increase in eGFR [treatment effect: week 4, 2.11 ± 1.21 (P = 0.082); week 12, 2.41 ± 1.33 (P = 0.070); and week 24, 2.98 ± 1.44 mL/min/1.73 m(2) (P = 0.039)]. This effect was seen in all pre-specified subgroups (P > 0.20 for interactions). No interaction between the favourable effects of FCM and baseline renal function was seen for the primary endpoints [improvement in Patient Global Assessment (P = 0.43) and NYHA class (P = 0.37) at 24 weeks]. Safety and adverse event profiles were similar in patients with baseline eGFR <60 and ≥60 mL/min/1.73 m(2) .

CONCLUSIONS

Treatment of iron deficiency in CHF patients with i.v. FCM was associated with an improvement in renal function. FCM therapy was effective and safe in CHF patients with renal dysfunction.

Strategies for preserving residual renal function in peritoneal dialysis patients

Although there have been many advancements in the treatment of patients with chronic kidney disease (CKD) over the last 50 years, in terms of reducing cardiovascular risk, mortality remains unacceptably high, particularly for those patients who progress to stage 5 CKD and initiate dialysis (CKD5d). As mortality risk increases exponentially with progressive CKD stage, the question arises as to whether preservation of residual renal function once dialysis has been initiated can reduce mortality risk. Observational studies to date have reported an association between even small amounts of residual renal function and improved patient survival and quality of life. Dialysis therapies predominantly provide clearance for small water-soluble solutes, volume and acid-base control, but cannot reproduce the metabolic functions of the kidney. As such, protein-bound solutes, advanced glycosylation end-products, middle molecules and other azotaemic toxins accumulate over time in the anuric CKD5d patient. Apart from avoiding potential nephrotoxic insults, observational and interventional trials have suggested that a number of interventions and treatments may potentially reduce the progression of earlier stages of CKD, including targeted blood pressure control, reducing proteinuria and dietary intervention using combinations of protein restriction with keto acid supplementation. However, many interventions which have been proven to be effective in the general population have not been equally effective in the CKD5d patient, and so the question arises as to whether these treatment options are equally applicable to CKD5d patients. As strategies to help preserve residual renal function in CKD5d patients are not well established, we have reviewed the evidence for preserving or losing residual renal function in peritoneal dialysis patients, as urine collections are routinely collected, whereas few centres regularly collect urine from haemodialysis patients, and haemodialysis dialysis patients are at risk of sudden intravascular volume shifts associated with dialysis treatments. On the other hand, peritoneal dialysis patients are exposed to a variety of hypertonic dialysates and episodes of peritonitis. Whereas blood pressure control, using an angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB), and low-protein diets along with keto acid supplementation have been shown to reduce the rate of progression in patients with earlier stages of CKD, the strategies to preserve residual renal function (RRF) in dialysis patients are not well established. For peritoneal dialysis patients, there are additional technical factors that might aggravate the rate of loss of residual renal function including peritoneal dialysis prescriptions and modality, bio-incompatible dialysis fluid and over ultrafiltration of fluid causing dehydration. In this review, we aim to evaluate the evidence of interventions and treatments, which may sustain residual renal function in peritoneal dialysis patients.

Anticoagulation in chronic kidney disease patients-the practical aspects

There is an increasing awareness about the risks of arterial and venous thromboembolism (TE) in hospital patients and general public which has led to consideration of thrombosis prevention measures in earnest. Early recognition of the symptoms of TE disease has led to timely administration of antiplatelet and anticoagulant drugs, translating to better outcome in many of these patients. In this respect, patients with chronic kidney disease (CKD) represent a special group. They indeed represent a high-risk group for thrombosis both in the cardiovascular territory and also in the venous circulation. At the same time, abnormalities in the platelet membranes put them at risk of bleeding which is significantly more than other patients with chronic diseases. Anticoagulation may be ideal to prevent the former, but the co-existing bleeding risk and also that the commonly used drugs for inhibiting coagulation are eliminated by renal pathways pose additional problems. In this review, we try to explain the complex thrombotic-haemorrhagic state of chronic kidney disease patients, and practical considerations for the management of anticoagulation in them with a focus on heparins.

Plasma adrenomedullin and subclinical cardiorenal syndrome in patients with type 2 diabetes mellitus

OBJECTIVE

To evaluate whether plasma adrenomedullin is involved in the previously reported significant inverse correlation between left ventricular (LV) end-diastolic pressure (peak velocity of early transmitral flow/peak velocity of early diastolic mitral annular motion ratio [E/E' ]) and estimated glomerular filtration rate (eGFR) in patients with type 2 diabetes mellitus, mild-to-moderate renal function impairment and LV relaxation impairment (E'≤7.1 cm/s).

METHODS

Plasma adrenomedullin concentration, E/E' and eGFR were assessed in 82 patients with type 2 diabetes.

RESULTS

Plasma adrenomedullin concentration was positively correlated with eGFR in patients with or without LV relaxation impairment, and inversely correlated with E/E' in patients with LV relaxation impairment. Multivariate linear regression analysis supported a role for plasma adrenomedullin in the association between E/E' and eGFR.

CONCLUSION

These results support the hypothesis that adrenomedullin modulates the interaction between the heart and kidneys in early subclinical cardiorenal syndrome in patients with type 2 diabetes mellitus.

Cardiorenal syndrome in critical care: the acute cardiorenal and renocardiac syndromes

Heart and kidney disease often coexist in the same patient, and observational studies have shown that cardiac disease can directly contribute to worsening kidney function and vice versa. Cardiorenal syndrome (CRS) is defined as a complex pathophysiological disorder of the heart and the kidneys in which acute or chronic dysfunction in one organ may induce acute or chronic dysfunction in the other organ. This has been recently classified into five subtypes on the basis of the primary organ dysfunction (heart or kidney) and on whether the organ dysfunction is acute or chronic. Of particular interest to the critical care specialist are CRS type 1 (acute cardiorenal syndrome) and type 3 (acute renocardiac syndrome). CRS type 1 is characterized by an acute deterioration in cardiac function that leads to acute kidney injury (AKI); in CRS type 3, AKI leads to acute cardiac injury and/or dysfunction, such as cardiac ischemic syndromes, congestive heart failure, or arrhythmia. Both subtypes are encountered in high-acuity medical units; in particular, CRS type 1 is commonly seen in the coronary care unit and cardiothoracic intensive care unit. This paper will provide a concise review of the epidemiology, pathophysiology, prevention strategies, and selected kidney management aspects for these two acute CRS subtypes.

Eplerenone survival benefits in heart failure patients post-myocardial infarction are independent from its diuretic and potassium-sparing effects. Insights from an EPHESUS (Eplerenone Post-Acute Myocardial Infarction Heart Failure Efficacy and Survival Study) substudy

OBJECTIVES

The purpose of this study was to determine whether a diuretic effect may be detectable in patients treated with eplerenone, a mineralocorticoid receptor antagonist, as compared with placebo during the first month of EPHESUS (Eplerenone Post-Acute Myocardial Infarction Heart Failure Efficacy and Survival study) (n = 6,080) and whether this was associated with eplerenone's beneficial effects on cardiovascular outcomes.

BACKGROUND

The mechanism of the survival benefit of eplerenone in patients with heart failure post-myocardial infarction remains uncertain.

METHODS

A diuretic effect was indirectly estimated by changes at 1 month that was superior to the median changes in the placebo group in body weight (-0.05 kg) and in the estimated plasma volume reduction (+1.4%). A potassium-sparing effect was defined as a serum potassium increase greater than the median change in the placebo group: +0.11 mmol/l.

RESULTS

In the eplerenone group, body weight (p < 0.0001) and plasma volume (p = 0.047) decreased, whereas blood protein and serum potassium increased (both, p < 0.0001), as compared with the placebo group, suggesting a diuretic effect induced by eplerenone, associated with a potassium-sparing effect. A diuretic effect, as defined by an estimated plasma volume reduction, was independently associated with 11% to 19% better outcomes (lower all-cause death, cardiovascular death or cardiovascular hospitalization, all-cause death or hospitalization, hospitalization for heart failure). Potassium sparing was also independently associated with 12% to 34% better outcomes. There was no statistically significant interaction between the observed beneficial effects of eplerenone (9% to 17%) on cardiovascular outcomes and potassium-sparing or diuretic effects.

CONCLUSIONS

Eplerenone's beneficial effects on long-term survival and cardiovascular outcomes are independent from early potassium-sparing or diuretic effects, suggesting that mineralocorticoid receptor antagonism provides cardiovascular protection beyond its diuretic and potassium-sparing properties.

Cardiovascular disease in chronic kidney disease. A clinical update from Kidney Disease: Improving Global Outcomes (KDIGO)

Cardiovascular morbidity and mortality in patients with chronic kidney disease (CKD) is high, and the presence of CKD worsens outcomes of cardiovascular disease (CVD). CKD is associated with specific risk factors. Emerging evidence indicates that the pathology and manifestation of CVD differ in the presence of CKD. During a clinical update conference convened by the Kidney Disease: Improving Global Outcomes (KDIGO), an international group of experts defined the current state of knowledge and the implications for patient care in important topic areas, including coronary artery disease and myocardial infarction, congestive heart failure, cerebrovascular disease, atrial fibrillation, peripheral arterial disease, and sudden cardiac death. Although optimal strategies for prevention, diagnosis, and management of these complications likely should be modified in the presence of CKD, the evidence base for decision making is limited. Trials targeting CVD in patients with CKD have a large potential to improve outcomes.

Critical care issues in patients after liver transplantation

The majority of patients who undergo liver transplantation (LT) spend some time in the intensive care unit during the postoperative period. For some, this is an expected part of the immediate posttransplant recovery period, whereas for others, the stay is more prolonged because of preexisting conditions, intraoperative events, or postoperative complications. In this review, 4 topics that are particularly relevant to the postoperative intensive care of LT recipients are discussed, with an emphasis on current knowledge specific to this patient group. Infectious complications are the most common causes of early posttransplant morbidity and mortality. The common patterns of infection seen in patients after LT and their management are discussed. Acute kidney injury and renal failure are common in post-LT patients. Kidney injury identification, etiologies, and risk factors and approaches to management are reviewed. The majority of patients will require weaning from mechanical ventilation in the immediate postoperative period; the approach to this is discussed along with the approach for those patients who require a prolonged period of mechanical ventilation. A poorly functioning graft requires prompt identification and appropriate management if the outcomes are to be optimized. The causes of poor graft function are systematically reviewed, and the management of these grafts is discussed.