Hemodynamic and neurochemical determinates of renal function in chronic heart failure

Estimated glomerular filtration rate, haemodynamics, and mortality in patients with aortic stenosis

BACKGROUND

In aortic stenosis (AS), estimated glomerular filtration rate (eGFR) is an important prognostic marker but its haemodynamic determinants are unknown. We investigated the correlation between eGFR and invasive haemodynamics and long-term mortality in AS patients undergoing aortic valve replacement (AVR).

METHODS

We studied 503 patients [median (interquartile range) age 76 (69-81) years] with AS [indexed aortic valve area .42 (.33-.49) cm² /m² ] undergoing cardiac catheterization prior to surgical (72%) or transcatheter (28%) AVR. Serum creatinine was measured on the day before cardiac catheterization for eGFR calculation (CKD-EPI formula).

RESULTS

The median eGFR was 67 (53-82) mL/min/1.73 m² . There were statistically significant correlations between eGFR and mean right atrial pressure (r = -.13; p = .004), mean pulmonary artery pressure (mPAP; r = -.25; p < .001), mean pulmonary artery wedge pressure (r = -.19; p < .001), pulmonary vascular resistance (r = -.21; p < .001), stroke volume index (r = .16; p < .001), extent of coronary artery disease, and mean transvalvular gradient but not indexed aortic valve area. In multivariate linear regression, higher age, lower haemoglobin, lower mean transvalvular gradient (i.e. lower flow), lower diastolic blood pressure, and higher mPAP were independent predictors of lower eGFR. After a median post-AVR follow-up of 1348 (948-1885) days mortality was more than two-fold higher in patients in the first eGFR quartile compared to those in the other three quartiles [hazard ratio 2.18 (95% confidence interval 1.21-3.94); p = .01].

CONCLUSION

In patients with AS, low eGFR is a marker of an unfavourable haemodynamic constellation as well as important co-morbidities. This may in part explain the association between low eGFR and increased post-AVR mortality.

Comprehensive and Safe Decongestion in Acutely Decompensated Heart Failure

PURPOSE OF THE REVIEW

Progressive intravascular, interstitial, and alveolar fluid overload underlies the transition from compensated to acutely decompensated heart failure and loop diuretics are the mainstay of treatment. Adverse effects and resistance to loop diuretics received much attention while the contribution of a depressed cardiac output to diuretic resistance was downplayed.

RECENT FINDINGS

Analysis of experience with positive inotropic agents, especially dobutamine, indicates that enhancement of cardiac output is not consistently associated with increased renal blood flow. However, urinary output and renal sodium excretion increase likely due to dobutamine-mediated decrease in renal and systemic reduced activation of sympathetic nervous- and renin-angiotensin-aldosterone system. Mechanical circulatory support with left ventricular assist devices ascertained the contribution of low cardiac output to diuretic resistance and the pathogenesis and progression of kidney disease in acutely decompensated heart failure. Diuretic resistance commonly occurs in acutely decompensated heart failure. However, failure to resolve fluid overload despite high doses of loop diuretics should alert to the presence of a low cardiac output state.

Intrarenal Doppler Ultrasound Renal Venous Stasis Index Correlates With Acute Cardiorenal Syndrome in Patients With Acute Decompensated Heart Failure

Background

Acute cardiorenal syndrome (ACRS) is associated with adverse outcomes in patients with acute decompensated heart failure (ADHF). Intrarenal venous blood flow can be assessed using Doppler ultrasound and has prognostic significance in ADHF. Although intrarenal Doppler (IRD) may be sensitive to renal congestion, an association between IRD parameters and ACRS has not been demonstrated in an ADHF population.

Methods

Hospitalized patients with ADHF (n = 21) or acute coronary syndrome (ACS; n = 21) were prospectively enrolled. Patients underwent echocardiography, including IRD, using a standard cardiac ultrasound transducer. Intrarenal venous flow was quantified with the renal venous stasis index (RVSI), defined as the duration of absent venous flow time divided by cardiac cycle duration. The primary outcome was acute kidney injury (AKI) as assessed using the Kidney Disease: Improving Global Outcomes (KDIGO) criteria.

Results

ADHF patients had a similar cardiac index (2.0 ± 0.6 vs 2.1 ± 0.4 L/min per m², P = 0.91) but higher estimated central venous pressure (13.0 ± 3.2 vs 4.6 ± 2.4 mm Hg, P < 0.001) measured using echocardiography, compared with ACS patients. IRD was abnormal in all ADHF patients and normal in all ACS patients (RVSI 0.62 ± 0.20 vs 0.0 ± 0, P < 0.001). AKI stage II/III occurred in 10 of 21 ADHF patients (48%) vs 0 of 21 ACS patients (P < 0.001), with a mean rise in serum creatinine of 97.7 ± 79.3 vs 16.8 ± 10.9 μmol/L (P < 0.001), respectively. RVSI was correlated with AKI severity in ADHF patients (r = 0.57; P = 0.004).

Conclusions

RVSI is associated with AKI among ADHF patients and may be a useful diagnostic biomarker for ACRS in this setting. Further studies are needed to validate this finding and evaluate the potential efficacy of IRD-guided decongestive therapy in this setting.

Haemodynamic parameters associated with renal function prior to and following heart transplantation

Aims

Abnormal renal function is a common feature in patients on heart transplant waiting lists. This study aimed to identify the haemodynamic parameters associated with decreased estimated glomerular filtration rate (eGFR) in patients listed for heart transplantation (HT) and renal function improvement following HT.

Methods and results

A total of 176 adults (52 years old, 81% men) with available right heart catheterization (RHC) listed in our centre for HT between 2014 and 2019 were studied. Cardiac catheterization measurements were obtained at time of HT listing evaluation. Changes in renal function were assessed between RHC and 6 months after HT. Median eGFR was 63 mL/min/1.73 m² at time of RHC. Central venous pressure > 10 mmHg was associated with a two‐fold increase in the likelihood of eGFR < 60 mL/min/1.73 m² at time of RHC (adjusted odd ratio, 2.2; 95% confidence interval, 1.1–4.7; P = 0.04). In the 134 patients (76%) who underwent HT during follow‐up, eGFR decreased by 7.9 ± 29.7 mL/min/1.73 m² from RHC to 6 months after HT. In these patients, low cardiac index (<2.1 L/min/m²) at initial RHC was associated with a (adjusted) 6 month post‐HT eGFR improvement of 12.2 mL/min/1.73 m² (P = 0.018). Patients with eGFR < 60 mL/min/1.73 m² and low cardiac index at time of RHC exhibited the greatest eGFR improvement (delta eGFR = 18.3 mL/min/1.73 m²) while patients with eGFR ≥ 60 mL/min/1.73 m² and normal cardiac index had a marked decrease in eGFR (delta eGFR = −27.7 mL/min/1.73 m², P < 0.001).

Conclusions

Central venous pressure is the main haemodynamic parameter associated with eGFR < 60 mL/min/1.73 m² in patients listed for HT. Low cardiac index prior to HT is associated with post‐transplant renal function recovery.

Renal, Cardiac, and Autonomic Effects of Catheter-Based Renal Denervation in Ovine Heart Failure

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Harnessing the Benefits of Endogenous Hydrogen Sulfide to Reduce Cardiovascular Disease

Cardiovascular disease is the leading cause of death in the U.S. While various studies have shown the beneficial impact of exogenous hydrogen sulfide (H₂S)-releasing drugs, few have demonstrated the influence of endogenous H₂S production. Modulating the predominant enzymatic sources of H₂S-cystathionine-β-synthase, cystathionine-γ-lyase, and 3-mercaptopyruvate sulfurtransferase-is an emerging and promising research area. This review frames the discussion of harnessing endogenous H₂S within the context of a non-ischemic form of cardiomyopathy, termed diabetic cardiomyopathy, and heart failure. Also, we examine the current literature around therapeutic interventions, such as intermittent fasting and exercise, that stimulate H₂S production.

Volume Balance in Chronic Kidney Disease: Evaluation Methodologies and Innovation Opportunities

BACKGROUND

Patients affected by chronic kidney disease are at a risk of cardiovascular morbidity and mortality. Body fluids unbalance is one of the main characteristics of this condition, as fluid overload is highly prevalent in patients affected by the cardiorenal syndrome.

SUMMARY

We describe the state of the art and new insights into body volume evaluation. The mechanisms behind fluid balance are often complex, mainly because of the interplay of multiple regulatory systems. Consequently, its management may be challenging in clinical practice and even more so out-of-hospital. Availability of novel technologies offer new opportunities to improve the quality of care and patients' outcome. Development and validation of new technologies could provide new tools to reduce costs for the healthcare system, promote personalized medicine, and boost home care. Due to the current COVID-19 pandemic, a proper monitoring of chronic patients suffering from fluid unbalances is extremely relevant. Key Message: We discuss the main mechanisms responsible for fluid overload in different clinical contexts, including hemodialysis, peritoneal dialysis, and heart failure, emphasizing the potential impact provided by the implementation of the new technologies.

Cardiovascular Autonomic Disturbances in Heart Failure With Preserved Ejection Fraction

In heart failure with reduced ejection fraction (HFrEF), diminished tonic and reflex vagal heart rate modulation and exaggerated sympathetic outflow and neural norepinephrine release are evident from disease inception. Each of these disturbances of autonomic regulation has been independently associated with shortened survival, and β-adrenoceptor antagonism and therapeutic autonomic modulation by other means have been demonstrated, in clinical trials, to lessen symptoms and prolong survival. In contrast, data concerning the autonomic status of patients with heart failure with preserved ejection fraction (HFpEF) are comparatively sparse. Little is known concerning the prognostic consequences of autonomic dysregulation in such individuals, and therapies applied with success in HFrEF have in most trials failed to improve symptoms or survival of those with HFpEF. A recent HFpEF Expert Scientific Panel report emphasised that without a deeper understanding of the pathophysiology of HFpEF, establishing effective treatment will be challenging. One aspect of such pathology may be cardiovascular autonomic disequilibrium, often worsened by acute exercise or routine daily activity. This review aims to summarise existing knowledge concerning parasympathetic and sympathetic function of patients with HFpEF, consider potential mechanisms and specific consequences of autonomic disturbances that have been identified, and propose hypotheses for future investigation.

Differential effects of inotropes and inodilators on renal function in acute cardiac care

Pathological interplay between the heart and kidneys is widely encountered in heart failure (HF) and is linked to worse prognosis and quality of life. Inotropes, along with diuretics and vasodilators, are a core medical response to HF but decompensated patients who need inotropic support often present with an acute worsening of renal function. The impact of inotropes on renal function is thus potentially an important influence on the choice of therapy. There is currently relatively little objective data available to guide the selection of inotrope therapy but recent direct observations on the effects of levosimendan and milrinone on glomerular filtration favour levosimendan. Other lines of evidence indicate that in acute decompensated HF levosimendan has an immediate renoprotective effect by increasing renal blood flow through preferential vasodilation of the renal afferent arterioles and increases in glomerular filtration rate: potential for renal medullary ischaemia is avoided by an offsetting increase in renal oxygen delivery. These indications of a putative reno-protective action of levosimendan support the view that this calcium-sensitizing inodilator may be preferable to dobutamine or other adrenergic inotropes in some settings by virtue of its renal effects. Additional large studies will be required, however, to clarify the renal effects of levosimendan in this and other relevant clinical situations, such as cardiac surgery.