Cardio-renal syndrome: new perspective in diagnostics

Chronic Kidney Disease as a Comorbidity in Heart Failure

Heart failure (HF) is one of the greatest problems in healthcare and it often coexists with declining renal function. The pathophysiology between the heart and the kidneys is bidirectional. Common mechanisms leading to the dysfunction of these organs result in a vicious cycle of cardiorenal deterioration. It is also associated with difficulties in the treatment of aggravating HF and chronic kidney disease (CKD) and, as a consequence, recurrent hospitalizations and death. As the worsening of renal function has an undeniably negative impact on the outcomes in patients with HF, searching for new treatment strategies and identification of biomarkers is necessary. This review is focused on the pathomechanisms in chronic kidney disease in patients with HF and therapeutic strategies for co-existing CKD and HF.

The association between the renal resistive index and the myocardial performance index in the general population

OBJECTIVE

The renal resistive index (RRI) is the most described measure of renal hemodynamics. The myocardial performance index (MPI) is widely used to assess overall myocardial performance. In this study, we aimed to investigate the relationship between renal hemodynamics, assessed by the RRI, and cardiac functions, assessed by the MPI in the general population.

METHODS

This single-center, cross-sectional study included a total of 302 consecutive patients who presented to our outpatient cardiology clinic between October 2019 and February 2020. All patients underwent transthoracic echocardiography and renal Doppler ultrasonography. The study population was divided into two groups: low RRI group (RRI ≤ 0.7, n = 236) and high RRI group (RRI > 0.7, n = 66).

RESULTS

E/A ratio, left ventricular ejection fraction (LVEF), and the MPI were significantly higher in the high RRI group than in the low RRI group (61.3 ± 15.4 vs 55.3 ± 16.4, P = .010 for E velocity; 0.9 ± 0.3 vs 0.7 ± 0.2, P = .008 for E/A ratio; 57.7 ± 4.7 vs 53.2 ± 10.1, P = .029 for LVEF; 0.52 ± 0.1 vs 0.43 ± 0.1, P < .001 for the MPI). A stepwise linear regression analysis demonstrated that LVEF (β = .123, P = .026), E velocity (β = .221, P < .001), and the MPI (β = .392, P < .001) were independently associated with the RRI.

CONCLUSION

Left ventricular ejection fraction and intra-cardiac Doppler blood flow indices, including E velocity and the MPI, were significantly and independently associated with the RRI in the general population.

The role of kidney injury molecule-1 in predicting cardiorenal syndrome type 1 after diuretic treatment

Introduction

Cardiorenal syndrome (CRS) is defined as acute or chronic dysfunction in the heart and kidney due to important interactions between the heart and kidney disease. The aim of this study was to evaluate prediction of CRS type 1 by measuring kidney injury molecule-1 (KIM-1) and to establish early diagnosis of acute kidney injury (AKI).

Material and methods

During 2015–2016, 146 patients who were admitted to the emergency service with acute decompensated HF were included in the study. We investigated urinary KIM-1 levels in 146 consecutive patients with decompensated heart failure before and after diuretic treatment. Statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS – version 21.0)/Windows Statistical Software. P-values less than < 0.05 were considered significant.

Results

There was a moderate negative correlation between the percentage change of creatinine values and the percentage change of KIM-1 values (r = –0.357, p = 0.016). There was no statistically significant relationship between KIM-1 and the development of CRS type 1 (p = 0.011).

Conclusions

No statistically significant relationship was observed between KIM-1 levels and the development of CRS type 1. In addition, there was no correlation between mortality in patients and KIM-1 values. It is thought that KIM-1 is not a potential prognostic indicator because renal tubular damage is only one of many factors in the pathophysiology of CRS type 1 and heart failure.

Moving From Heart Failure Guidelines to Clinical Practice: Gaps Contributing to Readmissions in Patients With Multiple Comorbidities and Older Age

This feature article for the thematic series on congestive heart failure (CHF) readmissions aims to outline important gaps in guidelines for patients with multiple comorbidities and the elderly. Congestive heart failure diagnosis manifests as a 3-phase journey between the hospital and community, during acute, chronic stable, and end-of-life (palliative) phases. This journey requires in variable intensities a combination of multidisciplinary care within tertiary hospital or ambulatory care from hospital outpatients or primary health services, within the general community. Management goals are uniform, ie, to achieve the lowest New York Heart Association class possible, with improvement in ejection fraction, by delivering gold standard therapies within a CHF program. Comorbidities are an important common denominator that influences outcomes. Comorbidities include diabetes mellitus, chronic obstructive airways disease, chronic renal impairment, hypertension, obesity, sleep apnea, and advancing age. Geriatric care includes the latter as well as syndromes such as frailty, falls, incontinence, and confusion. Many systems still fail to comprehensively achieve all aspects of such programs. This review explores these factors.

Urinary semaphorin 3A as an early biomarker to predict contrast-induced acute kidney injury in patients undergoing percutaneous coronary intervention

Contrast-induced acute kidney injury (CI-AKI) is a serious complication of diagnostic coronary angiograph and percutaneous coronary intervention (PCI). However, the exact pathophysiological mechanisms underlying CI-AKI development are largely unknown. The present study examined whether urinary semaphorin 3A levels predict the development of CI-AKI in patients undergoing PCI. This study enrolled 168 patients with stable angina undergoing elective PCI. Serial urine samples, obtained at baseline and 2, 6, 12, 24, 36, and 48 h post-PCI were analyzed by semaphorin 3A and neutrophil gelatinase-associated lipocalin (NGAL) ELISA kit. AKI was defined as an increase in serum creatinine beyond 50% according to the RIFLE classification system. Receiver operator characteristic (ROC) curve analyses identified optimal semaphorin 3A and NGAL values for diagnosing CI-AKI. CI-AKI occurred in 20 of 168 patients. There were no significant differences in the baseline clinical characteristics and angiographic findings between non-AKI patients group and AKI patients group. Both urinary semaphorin 3A and NGAL levels significantly increased at 2 and 6 h post-PCI. ROC analysis showed that the cut-off value of 389.5 pg/mg semaphorin 3A at 2 h post-PCI corresponds to 94% sensitivity and 75% specificity and the cut-off value of 94.4 ng/mg NGAL at 2 h post-PCI corresponds to 74% sensitivity and 82% specificity. Logistic regression showed that semaphorin 3A levels at 2 and 6 h post-PCI were the significant predictors of AKI in our cohort. Urinary semaphorin 3A may be a promising early biomarker for predicting CI-AKI in patients undergoing PCI.

Chronic Heart Failure and Comorbid Renal Dysfunction - A Focus on Type 2 Cardiorenal Syndrome

The most important advancements in the Cardiorenal syndrome (CRS) are its definition and subsequent classifications. When the predominant pathology and pathophysiology is the heart, i.e. chronic heart failure (CHF), and where any renal impairment (RI) subsequent to this is secondary, the classification is type 2 CRS. There are unique differences in the pathophysiology and progression of individual subclasses. It is important to understand the evolution of CHF and consequences of subsequent RI as they are becoming increasingly prevalent, aggravate morbidity and mortality and limit many therapeutic options. In this paper we discuss the significance of the type 2 CRS patients in the context of the thematic series.

Clinical and Echocardiographic Factors Associated with Right Ventricular Systolic Dysfunction in Hemodialysis Patients

BACKGROUND

Chronic kidney disease is a disorder of epidemic proportions that impairs cardiac function. Cardiovascular diseases are the leading cause of death in hemodialysis patients, and the understanding of new nontraditional predictors of mortality could improve their outcomes. Right ventricular systolic dysfunction (RVSD) has recently been recognized as a predictor of cardiovascular death in heart failure and hemodialysis patients. However, the factors contributing to RVSD in hemodialysis patients remain unknown. The aim of this study was to evaluate the clinical and echocardiographic factors associated with RVSD in hemodialysis patients.

METHODS

A cross-sectional study was conducted in which 100 outpatients with end-stage renal disease on chronic hemodialysis were evaluated. A transthoracic echocardiographic examination was performed at optimal dry weight. Right ventricular systolic function was evaluated using tricuspid annular plane systolic excursion (TAPSE). Clinical and echocardiographic data were recorded for each patient. A multivariate linear logistic regression was created using RVSD (TAPSE <14 mm) as the dependent variable.

RESULTS

Fifteen patients with RVSD and 85 patients without RVSD were analyzed. TAPSE had a positive correlation with left ventricular ejection fraction (LVEF) and myocardial relaxation velocity. Independent contributors to RVSD were LVEF (OR 1.14, 95% CI 1.05-1.26), left ventricular mass index (OR 1.02, 95% CI 1.00-1.04), and myocardial relaxation velocity (OR 1.81, 95% CI 1.18-3.19).

CONCLUSIONS

Echocardiographic factors were significant contributors to RVSD. These measurements could be included as part of the routine workup in all end-stage renal disease patients on hemodialysis.

Renalase and Biomarkers of Contrast-Induced Acute Kidney Injury

BACKGROUND

Contrast-induced acute kidney injury (CI-AKI) remains one of the crucial issues related to the development of invasive cardiology. The massive use of contrast media exposes patients to a great risk of contrast-induced nephropathy and chronic kidney disease development, and increases morbidity and mortality rates. The serum creatinine concentration does not allow for a timely and accurate CI-AKI diagnosis; hence numerous other biomarkers of renal injury have been proposed. Renalase, a novel catecholamine-metabolizing amine oxidase, is synthesized mainly in proximal tubular cells and secreted into urine and blood. It is primarily engaged in the degradation of circulating catecholamines. Notwithstanding its key role in blood pressure regulation, renalase remains a potential CI-AKI biomarker, which was shown to be markedly downregulated in the aftermath of renal injury. In this sense, renalase appears to be the first CI-AKI marker revealing an actual loss of renal function and indicating disease severity.

SUMMARY

The purpose of this review is to summarize the contemporary knowledge about the application of novel biomarkers of CI-AKI and to highlight the potential role of renalase as a functional marker of contrast-induced renal injury.

KEY MESSAGES

Renalase may constitute a missing biochemical link in the mutual interplay between kidney and cardiac pathology known as the cardiorenal syndrome.

Bedside-to-Bench Translational Research for Chronic Heart Failure: Creating an Agenda for Clients Who Do Not Meet Trial Enrollment Criteria

Congestive heart failure (CHF) is a chronic condition usually without cure. Significant developments, particularly those addressing pathophysiology, mainly started at the bench. This approach has seen many clinical observations initially explored at the bench, subsequently being trialed at the bedside, and eventually translated into clinical practice. This evidence, however, has several limitations, importantly the generalizability or external validity. We now acknowledge that clinical management of CHF is more complicated than merely translating bench-to-bedside evidence in a linear fashion. This review aims to help explore this evolving area from an Australian perspective. We describe the continuation of research once core evidence is established and describe how clinician-scientist collaboration with a bedside-to-bench view can help enhance evidence translation and generalizability. We describe why an extension of the available evidence or generating new evidence is occasionally needed to address the increasingly diverse cohort of patients. Finally, we explore some of the tools used by basic scientists and clinicians to develop evidence and describe the ones we feel may be most beneficial.

Doppler indexes of left ventricular systolic and diastolic flow and central pulse pressure in relation to renal resistive index

BACKGROUND

The cardio-renal interaction occurs via hemodynamic and humoral factors. Noninvasive assessment of renal hemodynamics is currently possible by assessment of renal resistive index (RRI) derived from intrarenal Doppler arterial waveforms as ((peak systolic velocity - end-diastolic velocity)/peak systolic velocity). Limited information is available regarding the relationship between RRI and cardiac hemodynamics. We investigated these associations in randomly recruited subjects from a general population.

METHODS

In 171 participants (48.5% women; mean age, 52.2 years), using pulsed wave Doppler, we measured RRI (mean, 0.60) and left ventricular outflow tract (LVOT) and transmitral (E and A) blood flow peak velocities and its velocity time integrals (VTI). Using carotid applanation tonometry, we measured central pulse pressure and arterial stiffness indexes such as augmentation pressure and carotid-femoral pulse wave velocity.

RESULTS

In stepwise regression analysis, RRI independently and significantly increased with female sex, age, body weight, brachial pulse pressure, and use of β-blockers, whereas it decreased with body height and mean arterial pressure. In multivariable-adjusted models with central pulse pressure and arterial stiffness indexes as the explanatory variables, we observed a significant and positive correlation of RRI only with central pulse pressure (P < 0.0001). Among the Doppler indexes of left ventricular blood flow, RRI was significantly and positively associated with LVOT and E peak velocities (P ≤ 0.012) and VTIs (P ≤ 0.010).

CONCLUSIONS

We demonstrated that in unselected subjects RRI was significantly associated with central pulse pressure and left ventricular systolic and diastolic Doppler blood flow indexes. Our findings imply that in addition to the anthropometric characteristics, cardiac hemodynamic factors influence the intrarenal arterial Doppler waveform patterns.

Comorbid Heart Failure and Renal Impairment: Epidemiology and Management

Heart failure mortality is significantly increased in patients with baseline renal impairment and those with underlying heart failure who subsequently develop renal dysfunction. This accelerated progression occurs independent of the cause or grade of renal dysfunction and baseline risk factors. Recent large prospective databases have highlighted the depth of the current problem, while longitudinal population studies support an increasing disease burden. We have extensively reviewed the epidemiological and therapeutic data among these patients. The evidence points to a progression of heart failure early in renal impairment, even in the albuminuric stage. The data also support poor prescription of prognostic therapies. As renal function is the most important prognostic factor in heart failure, it is important to establish the current understanding of the disease burden and the therapeutic implications.