GLP-1 receptor agonists and cardiorenal outcomes in type 2 diabetes: an updated meta-analysis of eight CVOTs.

BACKGROUND: A meta-analysis is presented of cardiovascular outcome trials (CVOTs) comparing glucagon-like peptide-1 receptor agonists (GLP-1RA) versus placebo on cardiorenal outcomes in patients with type 2 diabetes mellitus (T2DM). METHODS: We did an electronic search up to June 30, 2021, for eligible trials. We did a meta-analysis of available trial data using a random-effects model to calculate overall hazard ratios (HRs) and 95% CI (confidence intervals). We included data from 8 CVOTs and 60,080 patients (72.4% with established cardiovascular disease). RESULTS: GLP-1RA reduced major cardiovascular events (MACE) by 14% (HR = 0.86, 95% CI 0.79-0.94, P = 0.006) with a non-significant heterogeneity between subgroups of patients with and without cardiovascular disease (P = 0.127). GLP-1RA also reduced the risk of cardiovascular death by 13% (P = 0.016), nonfatal stroke by 16% (P = 0.007), hospitalization for heart failure by 10% (P = 0.023), all-cause mortality by 12% (P = 0.012), and the broad composite kidney outcome by 17% (P = 0.012), which was driven by a reduction in macroalbuminuria only (HR = 0.74, 0.67-0.82, P < 0.001). CONCLUSIONS: GLP-1RA have moderate benefits on MACE, and also reduce hospitalization for heart failure and all-cause mortality; they also have robust benefits on reducing the incidence of macroalbuminuria.

Association Between Adaptive Servo-Ventilation Therapy and Renal Function.

Cardio-renal syndrome is a challenging clinical entity to manage, and is often associated with increased morbidity and mortality. We hypothesized that adaptive servo-ventilation (ASV), non-invasive positive pressure ventilation that ameliorates systemic/pulmonary congestion, may improve renal function in patients with symptomatic heart failure complicated by the cardio-renal syndrome. Patients with symptomatic congestive heart failure who underwent ASV therapy for over 1 month were included in this retrospective study. The trajectory of the estimated glomerular filtration ratio (eGFR) between the pre-1 month period and the post-one-month period (on ASV) were compared. A total of 81 patients (median 65 years old, 65 men) were included. eGFR decreased during the pre-1 month period from 52.7 (41.7, 64.6) down to 49.9 (37.3, 63.5) mL/minute/1.73 m2 (P < 0.001) whereas we observed an increase following one-month of ASV therapy up to 53.4 (38.6, 68.6) mL/minute/1.73 m2 (P = 0.022). A reduction in furosemide equivalent dose following the initiation of ASV therapy was independently associated with increases in eGFR with an adjusted odds ratio of 13.72 (95% confidence interval 3.40-55.3, P < 0.001). In conclusion, short-term ASV therapy was associated with the preservation of renal function, particularly when the dose of loop diuretics was concomitantly reduced.

Improvement of renal function after transcatheter aortic valve replacement and its impact on survival.

BACKGROUND: Chronic kidney disease as well as acute kidney injury are associated with adverse outcomes after transcatheter aortic valve replacement (TAVR). However, little is known about the prognostic implications of an improvement in renal function after TAVR. METHODS: Renal improvement (RI) was defined as a decrease in postprocedural creatinine in µmol/l of ≥1% compared to its preprocedural baseline value. A propensity score representing the likelihood of RI was calculated to define patient groups which were comparable regarding potential confounders (age, sex, BMI, NYHA classification, STS score, log. EuroSCORE, history of atrial fibrillation/atrial flutter, pulmonary disease, previous stroke, CRP, creatinine, hsTNT and NT-proBNP). The cohort was stratified into 5 quintiles according to this propensity score and the survival time after TAVR was compared within each subgroup. RESULTS: Patients in quintile 5 (n = 93) had the highest likelihood for RI. They were characterized by higher creatinine, lower eGFR, higher NYHA class, higher NT-proBNP, being mostly female and having shorter overall survival time. Within quintile 5, patients without RI had significantly shorter survival compared to patients with RI (p = 0.002, HR = 0.32, 95% CI = [0.15-0.69]). There was no survival time difference between patients with and without RI in the whole cohort (p = 0.12) and in quintiles 1 to 4 (all p > 0.16). Analyses of specific subgroups showed that among patients with NYHA class IV, those with RI also had a significant survival time benefit (p < 0.001, HR = 0.15; 95%-CI = [0.05-0.44]) compared to patients without RI. CONCLUSIONS: We here describe a propensity score-derived specific subgroup of patients in which RI after TAVR correlated with a significant survival benefit.

Sodium glucose cotransporter (SGLT)-2 inhibitors alleviate the renal stress responsible for sympathetic activation.

This review focuses on the pathogenic role of sodium glucose cotransporter (SGLT)-2 in the development of renal dysfunction and heart failure in patients with diabetes, by emphasizing the concept of reno-cardiac syndrome (kidney injury worsens cardiac condition) and by substantiating the deleterious effect of sympathetic overdrive in this context. Furthermore, the review proposes a mechanistic hypothesis to explain the benefits of SGLT2 inhibitors, specifically that SGLT-2 inhibitors reduce sympathetic activation at the renal level. To illustrate this point, several examples from both animal experiments and clinical observations are introduced. The bidirectional interaction of the heart and kidney were deeply implicated as an exacerbator of heart failure and renal failure without diabetes. Renal cortical ischemia and abnormal glucose metabolism of tubular epithelial cells are likely to exist as common pathologies in nondiabetic heart failure patients. It is no wonder why SGLT-2 inhibitors are specifically being studied even in the absence of diabetes, both for heart failure and also for renal failure.

Intra-abdominal pressure and its relationship with markers of congestion in patients admitted for acute decompensated heart failure.

Systemic congestion is one of the mechanisms involved in acute decompensated heart failure (ADHF). Increased intra-abdominal pressure (IAP), elicited by abdominal congestion, has been related to acute kidney injury and prognosis. Nonetheless, the link between diuretic response, surrogate markers of congestion and renal function remains poorly understood. We measured IAP in 43 patients from a non-interventional, exploratory, prospective, single center study carried out in patients admitted for ADHF. IAP was measured with a calibrated electronic manometer through a catheter inserted in the bladder. Normal IAP was defined as < 12 mmHg. At baseline, median IAP was 15 mmHg, with a reduction over the next 72 h to a median of 12 mmHg. A higher IAP at admission was associated with higher baseline blood urea (83 mg/dL [62-138] vs. 50 mg/dL [35-65]; p = 0.007) and creatinine (1.30 mg/dL vs. 0.95 mg/dL; p = 0.027), and with poorer diuretic response 72 h after admission, either measured by diuresis (14.4 mL/mg vs. 21.6 mL/mg; [p = 0.005]) or natriuresis (1.2 mEqNa/mg vs. 2.0 mEqNa/mg; [p = 0.008]). A higher incidence for 1-year all-cause mortality (45.0% vs. 16.7%; log-rank test = 0.041) was observed among those patients with IAP > 12 mmHg at 72 h. In patients with ADHF, higher IAP at admission is associated with poorer baseline renal function and impaired diuretic response. The persistence of IAP at 72 h above 12 mmHg associates to longer length of hospital stay and higher 1-year all-cause mortality.

Clinical Potential of Targeting Fibroblast Growth Factor-23 and αKlotho in the Treatment of Uremic Cardiomyopathy.

Chronic kidney disease is highly prevalent, affecting 10% to 15% of the adult population worldwide and is associated with increased cardiovascular morbidity and mortality. As chronic kidney disease worsens, a unique cardiovascular phenotype develops characterized by heart muscle disease, increased arterial stiffness, atherosclerosis, and hypertension. Cardiovascular risk is multifaceted, but most cardiovascular deaths in patients with advanced chronic kidney disease are caused by heart failure and sudden cardiac death. While the exact drivers of these deaths are unknown, they are believed to be caused by uremic cardiomyopathy: a specific pattern of myocardial hypertrophy, fibrosis, with both diastolic and systolic dysfunction. Although the pathogenesis of uremic cardiomyopathy is likely to be multifactorial, accumulating evidence suggests increased production of fibroblast growth factor-23 and αKlotho deficiency as potential major drivers of cardiac remodeling in patients with uremic cardiomyopathy. In this article we review the increasing understanding of the physiology and clinical aspects of uremic cardiomyopathy and the rapidly increasing knowledge of the biology of both fibroblast growth factor-23 and αKlotho. Finally, we discuss how dissection of these pathological processes is aiding the development of therapeutic options, including small molecules and antibodies, directly aimed at improving the cardiovascular outcomes of patients with chronic kidney disease and end-stage renal disease.

[Vascular dysfunction in Cardiorenal Syndrome type 4].

The Cardiorenal Syndrome type 4 (CRS-4) defines a pathological condition in which a primary chronic kidney disease (CKD) leads to a chronic impairment of cardiac function. The pathophysiology of CRS-4 and the role of arterial stiffness remain only in part understood. Several uremic toxins, such as uric acid, phosphates, advanced glycation end-products, asymmetric dimethylarginine, and endothelin-1, are also vascular toxins. Their effect on the arterial wall may be direct or mediated by chronic inflammation and oxidative stress. Uremic toxins lead to endothelial dysfunction, intima-media thickening and arterial stiffening. In patients with CRS-4, the increased aortic stiffness results in an increase of cardiac workload and left ventricular hypertrophy whereas the loss of elasticity results in decreased coronary artery perfusion pressure during diastole and increased risk of myocardial infarction. Since the reduction of arterial stiffness is associated with an increased survival in patients with CKD, the understanding of the mechanisms that lead to arterial stiffening in patients with CRS4 may be useful to select potential approaches to improve their outcome. In this review we aim at discussing current understanding of the pathways that link uremic toxins, arterial stiffening and impaired cardiac function in patients with CRS-4.

Impact of Cardio-Renal-Metabolic Comorbidities on Cardiovascular Outcomes and Mortality in Type 2 Diabetes Mellitus.

BACKGROUND: We evaluated the incremental contribution of chronic kidney disease (CKD) to the risk of major adverse cardiovascular (CV) events (MACE), heart failure (HF), and all-cause mortality (ACM) in type 2 diabetes mellitus (T2DM) patients and its importance relative to the presence of other cardio-renal-metabolic (CaReMe) comorbidities. METHODS: Patients (≥40 years) were identified at the time of T2DM diagnosis from US (Humedica/Optum) and UK (Clinical Practice Research Datalink) databases. Patients were monitored post-diagnosis for modified MACE (myocardial infarction, stroke, ACM), HF, and ACM. Adjusted hazard ratios were obtained using Cox proportional-hazards regression to evaluate the relative risk of modified MACE, HF, and ACM due to CKD. Patients were stratified by the presence or absence of atherosclerotic CV disease (ASCVD) and age. RESULTS: Between 2011 and 2015, of 227,224 patients identified with incident T2DM, 40,063 (17.64%) had CKD. Regardless of prior ASCVD, CKD was associated with higher risk of modified MACE, HF, and ACM; this excess hazard was more pronounced in older patients with prior ASCVD. In time-to-event analyses in the overall cohort, patients with T2DM + CKD or T2DM + CKD + hypertension + hyperlipidemia had increased risks for modified MACE, HF, and ACM versus patients with T2DM and no CaReMe comorbidities. Patients with CKD had higher risks for and shorter times to modified MACE, HF, and ACM than those without CKD. CONCLUSION: In T2DM patients, CKD presence was associated with higher risk of modified MACE, HF, and ACM. This may have risk-stratification implications for T2DM patients based on background CKD and highlights the potential importance of novel renoprotective strategies.

Continuation of Chronic Heart Failure Therapies During Heart Failure Hospitalization - a Review.

Randomized controlled trials have demonstrated the benefits of guideline-directed medical therapy in the outpatient setting for treatment of chronic heart failure. However, the benefits of continuation (or discontinuation) of major chronic heart failure therapies when treating acute heart failure during hospitalization are less clear. Real and anticipated worsening renal function, hyperkalemia and hypotension are the three major reasons for discontinuation of renin-angiotensin-aldosterone system inhibitors during hospitalization, and a failure to resume renin-angiotensin-aldosterone system inhibitors before discharge could worsen cardiovascular outcomes. Available data, mostly observational, shows that continuation or initiation of renin-angiotensin-aldosterone system inhibitors appears efficacious, safe, and well tolerated in majority of acute heart failure patients during hospitalization. Worsening renal function portends poor prognosis only if associated with congestion in acute heart failure, and clinicians should not de-escalate diuretic therapy routinely for worsening renal function.

Association of Optimal Blood Pressure With Critical Cardiorenal Events and Mortality in High-Risk and Low-Risk Patients Treated With Antihypertension Medications.

Importance: There are few studies comparing the optimal level of treated blood pressure (BP) between high- and low-risk patients. Objective: To examine whether optimally treated BP is different according to risk status. Design, Setting, and Participants: Population-based cohort study using data from the National Health Information Database in Korea from 2002 to 2015 and 2006 to 2017. A total of 1 402 975 adults aged 40 to 79 years who had no known cardiorenal disease were included. Exposures: Systolic BP treated with antihypertensive medication. Main Outcomes and Measures: The yearly rates of critical cardiorenal events and all-cause death were estimated according to the levels of treated systolic BP and the presence of 5 risk factors (hypertension, diabetes, hyperlipidemia, proteinuria, and smoking). Results: During the study periods, 225 103 of 487 412 participants (54.0% male; median [interquartile range] age, 50 [44-59] years) in the primary cohort and 360 503 of 915 563 participants (50.1% male; median [interquartile range] age, 52 [46-60] years) in the secondary cohort received antihypertensive treatment. In total, 28 411 of 51 292 cardiorenal incidents and 33 102 of 72 500 deaths were noted in ever-treated participants. The absolute increase in cardiorenal and mortality risk associated with inadequately treated BP was greater in participants with multiple risk factors than in those with 1 or 0 risk factors. The hazard ratios for critical cardiorenal events increased as the treated systolic BP increased to more than 130 to 140 mm Hg. The hazard ratio for all-cause mortality for patients with 3 or more risk factors and treated systolic BP within the range of 110 to 119 mm Hg was 1.21 (95% CI, 1.07-1.37); 130 to 139 mm Hg, 1.04 (95% CI, 0.98-1.11); 140 to 149 mm Hg, 1.12 (95% CI, 1.05-1.20); 150 to 159 mm Hg, 1.21 (95% CI, 1.11-1.32); and 160 mm Hg or greater, 1.46 (95% CI, 1.32-1.62) compared with high-risk patients with BP of 120 to 129 mm Hg. For participants with 1 or 0 risk factors and treated systolic BP within the range of 110 to 119 mm Hg, the hazard ratio was 1.14 (95% CI, 1.07-1.22); 130 to 139 mm Hg, 0.97 (95% CI, 0.93-1.02); 140 to 149 mm Hg, 1.00 (95% CI, 0.91-1.09); 150 to 159 mm Hg, 1.06 (95% CI, 0.99-1.14); and 160 mm Hg or greater, 1.26 (95% CI, 1.15-1.37). However, when categorized using cardiovascular risk calculators, there was no consistent trend in mortality thresholds of BP across the risk score categories. Conclusions and Relevance: These results suggest that intensive BP control is appropriate for reducing all-cause mortality in addition to cardiorenal risk in higher- rather than lower-risk patients. However, caution may be required when determining BP targets using current risk calculators.

Cardiorenal syndrome in incident peritoneal dialysis patients: What is its effect on patients' outcomes?

BACKGROUND: Peritoneal dialysis (PD) is increasingly used for long-term management of Cardiorenal Syndrome (CRS). We compared outcomes in incident PD patients according to their baseline heart failure status. METHODS: This retrospective cohort study evaluated all-cause and cardiovascular mortality in incident PD patients with different heart failure status (non-CRS, acute heart failure [AHF], type II CRS, type IV CRS) who started PD between 2006 and 2016 in the Peking University Third Hospital. RESULTS: Of 748 patients included in the study, there were 466 (62.3%), 214 (28.6%), 27 (3.6%), and 41 (5.5%) patients in the non-CRS, AHF, type II CRS and type IV CRS groups, respectively. Patients with CRS were older (p<0.001), with more diabetes mellitus (p<0.001), coronary heart history (p<0.001), higher estimated glomerular filtration rate (eGFR) (p<0.001), lower serum creatinine (p<0.001) and phosphorus levels (p = 0.003) compared to non-CRS patients. Respective all-cause survival rates for patients with non-CRS, AHF, type II CRS and type IV CRS were 90.6%, 87.1%, 85.2% and 84.8% at 1 year, and 63.1%, 47.7%, 27.3% and 35.1% at 5 years (p<0.001). The corresponding figures for cardiovascular survival were 93%, 92%, 84% and 81% at 1 year, and 67%, 59%, 55% and 54% at 5 years (p<0.001). However, after adjusting for confounding factors, the presence of CRS was not independently associated with all-cause mortality whereas type IV CRS (HR 2.10, 95% CI 1.03-4.28, p = 0.04) was associated with higher cardiovascular mortality as compared to without CRS. CONCLUSION: Incident PD patients with different types of CRS had higher rates of both all-cause and cardiovascular mortality compared with patients without CRS. However, these observed adverse outcomes may be related to associated older age and higher prevalence of comorbidities, rather than CRS per se, except for type IV CRS, treatment strategies to reduce high cardiovascular CVD mortality may needed.

Heart-kidney interactions: mechanistic insights from animal models.

Pathological changes in the heart or kidney can instigate the release of a cascade of cardiorenal mediators that promote injury in the other organ. Combined dysfunction of heart and kidney is referred to as cardiorenal syndrome (CRS) and has gained considerable attention. CRS has been classified into five distinct entities, each with different major pathophysiological changes. Despite the magnitude of the public health problem of CRS, the underlying mechanisms are incompletely understood, and effective intervention is unavailable. Animal models have allowed us to discover pathogenic molecular changes to clarify the pathophysiological mechanisms responsible for heart-kidney interactions and to enable more accurate risk stratification and effective intervention. Here, this article focuses on the use of currently available animal models to elucidate mechanistic insights in the clinical cardiorenal phenotype arising from primary cardiac injury, primary renal disease with special emphasis of chronic kidney disease-specific risk factors, and simultaneous cardiorenal/renocardiac dysfunction. The development of novel animal models that recapitulate more closely the cardiorenal phenotype in a clinical scenario and discover the molecular basis of this condition will be of great benefit.

Impact of renal dysfunction on the management and outcome of acute heart failure: results from the French prospective, multicentre, DeFSSICA survey.

OBJECTIVES: Cardiorenal syndrome (CRS) is the combination of acute heart failure syndrome (AHF) and renal dysfunction (creatinine clearance (CrCl) ≤60 mL/min). Real-life data were used to compare the management and outcome of AHF with and without renal dysfunction. DESIGN: Prospective, multicentre. SETTING: Twenty-six academic, community and regional hospitals in France. PARTICIPANTS: 507 patients with AHF were assessed in two groups according to renal function: group 1 (patients with CRS (CrCl ≤60 mL/min): n=335) and group 2 (patients with AHF with normal renal function (CrCl >60 mL/min): n=172). RESULTS: Differences were observed (group 1 vs group 2) at admission for the incidence of chronic heart failure (56.42% vs 47.67%), use of furosemide (60.9% vs 52.91%), insulin (15.52% vs 9.3%) and amiodarone (14.33% vs 4.65%); additionally, more patients in group 1 carried a defibrillator (4.78% vs 0%), had ≥2 hospitalisations in the last year (15.52% vs 5.81%) and were under the care of a cardiologist (72.24% vs 61.63%). Clinical signs were broadly similar in each group. Brain-type natriuretic peptide (BNP) and BNP prohormone were higher in group 1 than group 2 (1157.5 vs 534 ng/L and 5120 vs 2513 ng/mL), and more patients in group 1 were positive for troponin (58.2% vs 44.19%), had cardiomegaly (51.04% vs 37.21%) and interstitial opacities (60.3% vs 47.67%). The only difference in emergency treatment was the use of nitrates, (higher in group 1 (21.9% vs 12.21%)). In-hospital mortality and the percentage of patients still hospitalised after 30 days were similar between groups, but the median stay was longer in group 1 (8 days vs 6 days). CONCLUSIONS: Renal impairment in AHF should not limit the use of loop diuretics and/or vasodilators, but early assessment of pulmonary congestion and close monitoring of the efficacy of conventional therapies is encouraged to allow rapid and appropriate implementation of alternative therapies if necessary.

Use of Levosimendan in Intensive Care Unit Settings: An Opinion Paper.

Levosimendan is an inodilator that promotes cardiac contractility primarily through calcium sensitization of cardiac troponin C and vasodilatation via opening of adenosine triphosphate-sensitive potassium (KATP) channels in vascular smooth muscle cells; the drug also exerts organ-protective effects through a similar effect on mitochondrial KATP channels. This pharmacological profile identifies levosimendan as a drug that may have applications in a wide range of critical illness situations encountered in intensive care unit medicine: hemodynamic support in cardiogenic or septic shock; weaning from mechanical ventilation or from extracorporeal membrane oxygenation; and in the context of cardiorenal syndrome. This review, authored by experts from 9 European countries (Austria, Belgium, Czech republic, Finland, France, Germany, Italy, Sweden, and Switzerland), examines the clinical and experimental data for levosimendan in these situations and concludes that, in most instances, the evidence is encouraging, which is not the case with other cardioactive and vasoactive drugs routinely used in the intensive care unit. The size of the available studies is, however, limited and the data are in need of verification in larger controlled trials. Some proposals are offered for the aims and designs of these additional studies.

Prognostic Significance of Serum Indoxyl Sulfate and Albumin for Patients with Cardiovascular Disease.

The progression of renal dysfunction reduces serum albumin and deteriorates the binding capacity of protein-bound uremic toxins. We evaluated the prognostic implications of serum indoxyl sulfate (IS) and albumin levels in patients with cardiovascular disease.We prospectively enrolled 351 consecutive patients undergoing percutaneous revascularization for coronary artery disease or peripheral artery disease. The primary endpoint was all-cause mortality. Patients were assigned to four groups according to the median levels of serum IS (0.1 mg/dL) and albumin (3.9 g/dL).During the median follow-up time of 575 days, 16 patients died. The IS level was significantly higher in nonsurvivors (0.33 versus 0.85 mg/dL, P < 0.05). On the Kaplan-Meier curve, the high IS/low albumin group presented the highest mortality rate (log-rank test, P < 0.01). Cox proportional hazard analysis revealed that high IS/low albumin (hazard ratio (HR): 5.33; 95% confidence interval (CI): 1.71-16.5; P < 0.01), diastolic pressure (HR: 0.94; 95% CI: 0.91-0.98; P < 0.01), prior stroke (HR: 4.54; 95% CI: 1.33-15.4; P = 0.01), and left ventricular ejection fraction (LVEF) (HR: 0.92; 95% CI: 0.88-0.96; P < 0.001) were associated with increased mortality. Furthermore, the combination of IS and albumin levels significantly conferred an additive value to LVEF for predicting mortality (C-statistic: 0.69 versus 0.80; P < 0.001; net reclassification improvement: 0.83; P < 0.001; integrated discrimination improvement: 0.02; P = 0.02).A lower albumin level adds potentiating effects on IS as a prognostic factor for cardiovascular disease.

Parameters associated with therapeutic response using peritoneal dialysis for therapy refractory heart failure and congestive right ventricular dysfunction.

BACKGROUND: In patients with refractory heart failure (HF) peritoneal dialysis (PD) is associated with improved functional status and decrease in hospitalization. However, previous studies did not focus on right ventricular dysfunction as an important pathophysiologic component of cardiorenal syndrome. METHODS: In a prospective cohort study PD was started in 40 patients with refractory right HF (with/without left HF). Refractoriness to conservative therapy was defined as persistent right heart congestion/ascites with intensified diuretic treatment and/or ≥2 hospitalizations within 6 months because of cardiac decompensation despite optimal medical treatment, and/or acute renal failure during intensified conservative treatment of cardiac decompensations. RESULTS: Patient survival was 55.0% at 1 year, 35.0% at 2 years and 27.5% at 3 years. The number of hospitalization days declined after initiation of PD for both cardiac [13 (IQR 1-53) days before vs. 1 (IQR 0-12) days after start of PD, p<0.001] and unplanned reasons [12 (IQR 3-44) days before vs. 1 (IQR 0-33) days after start of PD, p = 0.007]. Using a combined endpoint including survival time of ≥1 year and either improvement in quality of life or decline in hospitalizations we found that patients with extended ascites, higher systolic pulmonary artery pressure, more marked impairment of right ventricular function and tricuspid valve insufficiency, higher residual renal function as well as those who could perform PD without assistance have benefited most from this therapy. CONCLUSIONS: Patients with more pronounced backward failure, less marked residual renal functional impairment and those not depending on assistance for therapy are likely to profit most from PD.

Cardiorenal Syndrome: An Overview.

It is well established that a large number of patients with acute decompensated heart failure present with various degrees of heart and kidney dysfunction usually primary disease of heart or kidney often involve dysfunction or injury to the other. The term cardiorenal syndrome increasingly had been used without a consistent or well-accepted definition. To include the vast array of interrelated derangements and to stress the bidirectional nature of heart-kidney interactions, a new classification of the cardiorenal syndrome with 5 subtypes that reflect the pathophysiology, the time frame, and the nature of concomitant cardiac and renal dysfunction was proposed. Cardiorenal syndrome can generally be defined as a pathophysiological disorder of the heart and kidneys, in which acute or chronic dysfunction of one organ may induce acute or chronic dysfunction to the other. Although cardiorenal syndrome was usually referred to as acute kidney dysfunction following acute cardiac disease, it is now clearly established that impaired kidney function can have an adverse impact on cardiac function.

Pathophysiological Mechanisms in Cardiorenal Syndrome.

Cardiorenal syndrome represents the confluence of intricate hemodynamic, neurohormonal, and inflammatory pathways that initiate and propagate the maladaptive cross talk between the heart and kidneys. Several of these pathophysiological principles were described in older historical experiments. The last decade has witnessed major efforts in streamlining its definition, clinical phenotypes, and classification to improve diagnostic accuracy and deliver optimal goal-directed medical therapies. The ability to characterize the various facets of cardiorenal syndrome based on its pathophysiology is poised in an exciting vantage point, in the backdrop of several advanced diagnostic strategies, notably cardiorenal biomarkers that may help with accurate delineation of clinical phenotype, prognosis, and delivery of optimal medical therapies in future studies. This promises to help integrate precision medicine into the clinical diagnosis and treatment strategies for cardiorenal syndrome and, through a heightened understanding of its pathophysiology, to deliver appropriate therapies that will reduce its associated morbidity and mortality.

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.