Decreased cardiac output, venous congestion and the association with renal impairment in patients with cardiac dysfunction

Cardiorenal syndrome: Plasmonic biosensors

Cardiorenal syndrome (CRS) is defined as a broad spectrum of conditions encompassing both the heart and kidneys in which acute or chronic heart disorder may induce acute or chronic tubular injury in the kidneys and vice versa. Early diagnosis allows timely intervention and attenuates disease progression. Two well-established biomarkers, neutrophil gelatinase-associated lipocalin (NGAL) and brain (B-type) natriuretic peptide (BNP), are reflective of impaired cardiac and kidney function associated with poor prognosis in various cardiac disorders, including heart failure and coronary artery disease. Given the ongoing contribution of CRS to the high morbidity and mortality post-MI, early risk stratification and preventive measures are highly significant. In this review, we examine Surface Plasmon Resonance (SPR) optical biosensors for detection of these biomarkers and discuss potential implications of this highly sensitive and specific technology in CRS detection, treatment and outcomes.

Association of Left Atrial Function With Incident Chronic Kidney Disease in Older Adults

Objective

To examine the association of left atrial (LA) function with incident chronic kidney disease (CKD) and assess the clinical utility of adding LA function to a CKD risk prediction equation.

Patients and Methods

We included 4002 Atherosclerosis Risk in Communities study participants without prevalent CKD (mean ± SD age, 75±5 years; 58% female, 18% Black). Left atrial function (reservoir, conduit, and contractile strain) was evaluated by 2D-echocardiograms on 2011 to 2013. Chronic kidney disease was defined as greater than 25% decline in estimated glomerular filtration rate of less than 60 mL/min/1.73 m2, end-stage kidney disease, or hospital records. Cox proportional hazards models were used. Risk prediction and decision curve analyses evaluated 5-year CKD risk by diabetes status.

Results

Median follow-up was 7.2 years, and 598 participants developed incident CKD. Incidence rate for CKD was 2.29 per 100 person-years. After multivariable adjustments, the lowest quintile of LA reservoir, conduit, and contractile strain (vs highest quintile) had a higher risk of CKD (hazard ratios [95% CIs]: 1.94 [1.42-2.64], 1.62 [1.19-2.20], and 1.49 [1.12-1.99]). Adding LA reservoir strain to the CKD risk prediction equation variables increased the C-index by 0.026 (95% CI: 0.005-0.051) and 0.031 (95% CI: 0.006-0.058) in participants without and with diabetes, respectively. Decision curve analysis found the model with LA reservoir strain had a higher net benefit than the model with CKD risk prediction equation variables alone.

Conclusion

Lower LA function is independently associated with incident CKD. Adding LA function to the CKD risk prediction enhances prediction and yields a higher clinical net benefit. These findings suggest that impaired LA function may be a novel risk factor for CKD.

Investigating the indirect therapeutic effect of hAMSCs utilizing a novel scaffold (PGS-co-PCL/PGC/PPy/Gelatin) in myocardial ischemia-reperfusion-induced renal failure in male Wistar rats

BACKGROUND

Myocardial ischemia-reperfusion (MI/R) occurs due to temporary or permanent interruptions in the coronary and circulatory system, indirectly affecting kidney function through reduced cardiac output for metabolic needs. In this study, the aim was to explore the indirect effects of using human amniotic membrane mesenchymal stem cells (hAMSCs) with the PGS-co-PCL/PGC/PPy/Gelatin scaffold in male rats with renal failure induced by miocardial ischemia-reperfusion.

METHODS

MI/R injury was induced in 48 male Wistar rats through left anterior descending artery ligation, divided into four groups (n=12); control group, cell group, scaffold group, and celss+scaffold group. Evaluations were conducted at two and thirty days post MI/R injury, encompassing echocardiography, biochemical, inflammatory markers analysis, and histological assessment.

RESULTS

Echocardiographic findings exhibited notable enhancement in ejection fraction, fractional shortening, and stroke volume of treated groups compared to controls after 30 days (P< 0.05). Serum creatinine (P< 0.001) and urea (P< 0.05) levels significantly decreased in the scaffold+cells group) compared to the control group. The treated cells+ scaffold group displayed improved kidney structure, evidenced by larger glomeruli and reduced Bowman's space compared to the control group (P< 0.01). Immunohistochemical analysis indicated reduced TNF-α protein in the scaffold+ cells group (P< 0.05) in contrast to the control group (P< 0.05). Inflammatory factors IL-6, TNF-α, and AKT gene expression in renal tissues were improved in scaffold+ cells-treated animals.

CONCLUSION

Our research proposes the combination of hAMSCs and the PGS-co-PCL/PGC/PPy/Gelatin scaffold in MI/R injured rats appears to enhance renal function and reduce kidney inflammation by improving cardiac output.

Ultrasound unveiling: Decoding venous congestion in heart failure for precision management of fluid status

This editorial discusses the manuscript by Di Maria et al, published in the recent issue of the World Journal of Cardiology. We here focus on the still elusive pathophysiological mechanisms underlying cardio-renal syndrome (CRS), despite its high prevalence and the substantial worsening of both kidney function and heart failure. While the measure of right atrial pressure through right cardiac catheterization remains the most accurate albeit invasive and costly procedure, integrating bedside ultrasound into diagnostic protocols may substantially enhance the staging of venous congestion and guide therapeutic decisions. In particular, with the assessment of Doppler patterns across multiple venous districts, the Venous Excess Ultrasound (VExUS) score improves the management of fluid overload and provides insight into the underlying factors contributing to cardio-renal interactions. Integrating specific echocardiographic parameters, particularly those concerning the right heart, may thus improve the VExUS score sensitivity, offering perspective into the nuanced comprehension of cardio-renal dynamics. A multidisciplinary approach that consistently incorporates the use of ultrasound is emerging as a promising advance in the understanding and management of CRS.

Excess renin is attributed to the combination of forward and backward failure in HFrEF

AIMS

Regulation of the renin-angiotensin system (RAS) in heart failure (HF) with reduced ejection fraction (HFrEF) still raises questions, as a large proportion of patients show normal renin levels despite manifest disease. Experimental venous congestion results in reduced renal perfusion pressure and stimulates renin secretion. We hypothesized that excess renin levels are mainly a result of right ventricular failure as a sequalae of left ventricular dysfunction. The study aimed to link right ventricular function (RVF) with renin levels and to investigate further contributors to excess RAS activation.

METHODS AND RESULTS

Three hundred thirty-two chronic HFrEF patients undergoing routine ambulatory care were consecutively enrolled in a prospective, registry-based, observational study. Laboratory parameters, including cardiac-specific markers renin, aldosterone, and N-terminal pro-brain natriuretic peptide (NT-proBNP), echocardiographic examination (n = 247), and right heart catheterization (n = 85), were documented. The relationship between renin and its respective parameters was analysed. Renin concentration was not associated with the New York Heart Association class or NT-proBNP. Systolic blood pressure, systemic vascular resistance, serum sodium, aldosterone, and lactate dehydrogenase were associated with increased renin levels (P < 0.035 for all). Renin levels similarly increased with worsening of RVF parameters such as fractional area change, tricuspid annular plane systolic excursion, tissue Doppler imaging, and inferior vena cava diameter (P < 0.011 for all), but not with pulmonary pressure. Excess renin levels were observed when worsening RVF was combined with reduced renal perfusion {625 μIU/mL [interquartile range (IQR): 182-1761] vs. 67 μIU/mL [IQR: 16-231], P < 0.001}, which was associated with worse survival.

CONCLUSIONS

While unrelated to classical indices of HF severity, circulating renin levels increase with the worsening of RVF, especially in the combined presence of forward and backward failure. This might explain normal renin levels in HFrEF patients but also excess renin levels in poor haemodynamic conditions.

VeXUS: Do Not Drown in the ExCESS

How to cite this article: Kumar V. VeXUS: Do Not Drown in the ExCESS. Indian J Crit Care Med 2024;28(5):419-421.

Changes in Natriuretic Peptide Levels and Subsequent Kidney Function Decline in SPRINT

RATIONALE & OBJECTIVE

Novel approaches to the assessment of kidney disease risk during hypertension treatment are needed because of the uncertainty of how intensive blood pressure (BP) lowering impacts kidney outcomes. We determined whether longitudinal N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurements during hypertension treatment are associated with kidney function decline.

STUDY DESIGN

Prospective observational study.

SETTING & PARTICIPANTS

8,005 SPRINT (Systolic Blood Pressure Intervention Trial) participants with NT-proBNP measurements at baseline and 1 year.

EXPOSURE

1-year change in NT-proBNP categorized as a ≥25% decrease, ≥25% increase, or <25% change (stable).

OUTCOME

Annualized change in estimated glomerular filtration rate (eGFR) and ≥30% decrease in eGFR.

ANALYTICAL APPROACH

Linear mixed-effect and logistic regression models were used to evaluate the association of changes in NT-proBNP with subsequent annualized change in eGFR and ≥30% decrease in eGFR, respectively. Analyses were stratified by baseline chronic kidney disease (CKD) status.

RESULTS

Compared with stable 1-year NT-proBNP levels, a ≥25% decrease in NT-proBNP was associated with a slower decrease in eGFR in participants with CKD (adjusted difference, 1.09%/y; 95% CI, 0.35-1.83) and without CKD (adjusted difference, 0.51%/y; 95% CI, 0.21-0.81; P = 0.4 for interaction). Meanwhile, a ≥25% increase in NT-proBNP in participants with CKD was associated with a faster decrease in eGFR (adjusted difference, -1.04%/y; 95% CI, -1.72 to -0.36) and risk of a ≥30% decrease in eGFR (adjusted odds ratio, 1.44; 95% CI, 1.06-1.96); associations were stronger in participants with CKD than in participants without CKD (P = 0.01 and P < 0.001 for interaction, respectively). Relationships were similar irrespective of the randomized BP arm in SPRINT (P > 0.2 for interactions).

LIMITATIONS

Persons with diabetes and proteinuria >1 g/d were excluded.

CONCLUSIONS

Changes in NT-proBNP during BP treatment are independently associated with subsequent kidney function decline, particularly in people with CKD. Future studies should assess whether routine NT-proBNP measurements may be useful in monitoring kidney risk during hypertension treatment.

PLAIN-LANGUAGE SUMMARY

N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a biomarker in the blood that reflects mechanical stress on the heart. Measuring NT-proBNP may be helpful in assessing the risk of long-term losses of kidney function. In this study, we investigated the association of changes in NT-proBNP with subsequent kidney function among individuals with and without chronic kidney disease. We found that increases in NT-proBNP are associated with a faster rate of decline of kidney function, independent of baseline kidney measures. The associations were more pronounced in individuals with chronic kidney disease. Our results advance the notion of considering NT-proBNP as a dynamic tool for assessing kidney disease risk.

Renal medullary oxygenation during laparoscopic vs open surgery: the impact of blood pressure management-a pilot randomized controlled trial

The impact of blood pressure targets and surgical approach (laparoscopic or open) on continuous urinary oxygenation (PuO2), a validated surrogate of renal medullary PO2, during general surgery, is unclear. We aimed to assess the effects of different blood pressure targets and surgical procedures on PuO2. We randomized patients receiving either laparoscopic or open surgery into two mean arterial pressure (MAP) target groups: usual MAP or a high MAP. We measured PuO2 in real-time and analyzed it according to the type of surgery and blood pressure target. The study was retrospectively registered on the 5th of July 2023 (ACTRN12623000726651). We included 43 participants who underwent either laparoscopic (n = 20) or open surgery (n = 23). We found that PuO2 significantly decreased during both laparoscopic and open surgery under a usual blood pressure target (- 51% and - 49%, respectively). However, there was a sharper fall with laparoscopic surgery resulting in a higher PuO2 with open surgery (mean difference: 11 ± 1 mmHg higher; p < 0.001). Targeting a higher MAP resulted in a higher PuO2 over time during laparoscopic surgery (mean difference: 7 ± 1 mmHg, p < 0.001). In contrast, targeting a usual MAP resulted in a higher PuO2 during open surgery (mean difference: 7 ± 1 mmHg, p < 0.001). Surgical approach and intraoperative blood pressure targets significantly impact urinary oxygenation. Further studies with larger sample sizes are needed to confirm these findings and understand their potential clinical implications.Registration number: ACTRN12623000726651; Date of registration: 05/07/2023 (retrospectively registered).

Evaluation of renal circulation in heart failure using superb microvascular imaging, a microvascular flow imaging system

PURPOSE

Renal circulation evaluation is essential in understanding the cardiorenal relationship in heart failure (HF), and there is a growing interest in imaging techniques that visualize renal circulation. This study aimed to assess the effectiveness of superb microvascular imaging (SMI) in evaluating renal circulation in HF patients.

METHOD

The study included 71 HF patients undergoing cardiac catheterization. Prior to catheterization, renal ultrasound examinations were performed. A control group of 18 subjects without HF was also included. SMI was used to measure the vascular index (VI), which was calculated as the percentage of blood flow signal area in the region of interest. The intrarenal perfusion index (IRPI) was determined as a fluctuation index of VI, reflecting variations in the number of blood cells moving through renal tissue during the cardiac cycle.

RESULTS

Using the upper 95% confidence interval of IRPI (0.6) from the control group, HF patients were classified into two groups. Patients with IRPI > 0.6 showed a more congestive profile. Right atrial pressure and biphasic or monophasic Doppler intrarenal flow pattern were independent determinants of IRPI > 0.6. In addition, IRPI remained a significant predictor of estimated glomerular filtration rate (eGFR).

CONCLUSION

The parameter IRPI as variations in SMI signal during the cardiac cycle may be a useful evaluation method for renal perfusion impairment in HF.

Hemodynamic Determinants of Cardiac Surgery-Associated Acute Kidney Injury

OBJECTIVES

Examine the: 1) relative role of hemodynamic determinants of acute kidney injury (AKI) obtained in the immediate postcardiac surgery setting compared with established risk factors, 2) their predictive value, and 3) extent mediation via central venous pressure (CVP) and mean arterial pressure (MAP).

DESIGN

Retrospective observational study. The main outcome of the study was moderate to severe AKI, per kidney disease: improving global outcomes, within 14 days of surgery.

SETTING

U.S. academic medical center.

PATIENTS

Adult patients undergoing cardiac surgery between January 2000 and December 2019 (n = 40,426) in a single U.S.-based medical center. Pulmonary artery catheter measurements were performed at a median of 102 minutes (11, 132) following cardiopulmonary bypass discontinuation.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

The median age of the cohort was 67 years (58, 75), and 33% were female; 70% had chronic hypertension, 29% had congestive heart failure, and 3% had chronic kidney disease. In a multivariable model, which included comorbidities and traditional intraoperative risk factors, CVP (p < 0.0001), heart rate (p < 0.0001), cardiac index (p < 0.0001), and MAP (p < 0.0001), were strong predictors of AKI, and superseded factors such as surgery type and cardiopulmonary bypass duration. The cardiac index had a significant interaction with heart rate (p = 0.026); a faster heart rate had a differentiating effect on the relationship of cardiac index with AKI, where a higher heart rate heightened the risk of AKI primarily in patients with low cardiac output. There was also significant interaction observed between CVP and MAP (p = 0.009); where the combination of elevated CVP and low MAP had a synergistic effect on AKI incidence.

CONCLUSIONS

Hemodynamic factors measured within a few hours of surgery showed a strong association with AKI. Furthermore, determinants of kidney perfusion, namely CVP and arterial pressure are interdependent; as are constituents of stroke volume, that is, cardiac output and heart rate.

Extrapulmonary manifestations of pulmonary arterial hypertension

INTRODUCTION

Extrapulmonary manifestations of pulmonary arterial hypertension (PAH) may play a critical pathobiological role and a deeper understanding will advance insight into mechanisms and novel therapeutic targets. This manuscript reviews our understanding of extrapulmonary manifestations of PAH.

AREAS COVERED

A group of experts was assembled and a complimentary PubMed search performed (October 2023 - March 2024). Inflammation is observed throughout the central nervous system and attempts at manipulation are an encouraging step toward novel therapeutics. Retinal vascular imaging holds promise as a noninvasive method of detecting early disease and monitoring treatment responses. PAH patients have gut flora alterations and dysbiosis likely plays a role in systemic inflammation. Despite inconsistent observations, the roles of obesity, insulin resistance and dysregulated metabolism may be illuminated by deep phenotyping of body composition. Skeletal muscle dysfunction is perpetuated by metabolic dysfunction, inflammation, and hypoperfusion, but exercise training shows benefit. Renal, hepatic, and bone marrow abnormalities are observed in PAH and may represent both end-organ damage and disease modifiers.

EXPERT OPINION

Insights into systemic manifestations of PAH will illuminate disease mechanisms and novel therapeutic targets. Additional study is needed to understand whether extrapulmonary manifestations are a cause or effect of PAH and how manipulation may affect outcomes.

EARLY TRAJECTORY OF VENOUS EXCESS ULTRASOUND SCORE IS ASSOCIATED WITH CLINICAL OUTCOMES OF GENERAL ICU PATIENTS

ABSTRACT

Background: Systemic venous congestion, assessed by the venous excess ultrasound (VExUS) score, has been associated with adverse effects, including acute kidney injury (AKI), in patients with cardiac disease. In general intensive care unit (ICU) patients, the association between VExUS score and outcomes is understudied. We aimed to investigate the association between the trajectory of VExUS score within the first 3 days of ICU admission and the composite clinical outcome of major adverse kidney events within 30 days (MAKE30). Methods: In this prospective observational study, including patients consecutively admitted to the ICU, VExUS score was calculated within 24 h after ICU admission (day 1) and at 48 to 72 h (day 3). D-VExUS was calculated as the difference between the VExUS score on day 3 minus that on day 1. Development of AKI within 7 days and all-cause mortality within 30 days were recorded. Results: A total of 89 patients (62% men; median age, 62 years; median Acute Physiology and Chronic Health Evaluation II score, 24) were included. Sixty (67%) patients developed AKI within 7 days, and 17 (19%) patients died within 30 days after ICU admission. D-VExUS was associated with MAKE30, even after adjustment for confounders (hazard ratio, 2.07; 95% confidence interval, 1.17-3.66; P = 0.01). VExUS scores on days 1 or 3 were not associated with MAKE30. Also, VExUS scores on day 1 or on day 3 and D-VExUS were not associated with development of AKI or mortality. Conclusions: In a general ICU cohort, early trajectory of VExUS score, but not individual VExUS scores at different time points, was associated with the patient-centered MAKE30 outcome. Dynamic changes rather than snapshot measurements may unmask the adverse effects of systemic venous congestion on important clinical outcomes.

Renal Congestion in Heart Failure: Insights in Novel Diagnostic Modalities

Heart failure is increasingly prevalent and is estimated to increase its burden in the following years. A well-reported comorbidity of heart failure is renal dysfunction, where predominantly changes in the patient's volume status, tubular necrosis or other mechanical and neurohormonal mechanisms seem to drive this impairment. Currently, there are established biomarkers evaluating the patient's clinical status solely regarding the cardiovascular or renal system. However, as the coexistence of heart and renal failure is common and related to increased mortality and hospitalization for heart failure, it is of major importance to establish novel diagnostic techniques, which could identify patients with or at risk for cardiorenal syndrome and assist in selecting the appropriate management for these patients. Such techniques include biomarkers and imaging. In regards to biomarkers, several peptides and miRNAs indicative of renal or tubular dysfunction seem to properly identify patients with cardiorenal syndrome early on in the course of the disease, while changes in their serum levels can also be helpful in identifying response to diuretic treatment. Current and novel imaging techniques can also identify heart failure patients with early renal insufficiency and assess the volume status and the effect of treatment of each patient. Furthermore, by assessing the renal morphology, these techniques could also help identify those at risk of kidney impairment. This review aims to present all relevant clinical and trial data available in order to provide an up-to-date summary of the modalities available to properly assess cardiorenal syndrome.

Impact of Contrast-Associated Acute Kidney Injury on One-Year Outcomes in Very Elderly STEMI Patients: Insights From a Multicenter Registry in Northern Italy

Data about contrast-associated acute kidney injury (CA-AKI) in oldest old (age ≥85 years) ST-elevation myocardial infarction (STEMI) patients are scarce. We evaluated the incidence and the 1-year prognostic impact of CA-AKI in this population. Patients were included in a multicenter real-world registry, and CA-AKI was defined according to KDIGO (Kidney Disease Improving Global Outcomes) criteria. Major adverse cardiac and cerebrovascular events (MACCEs) were defined as the composite of all-cause death, stroke, unplanned coronary revascularization, and heart failure hospitalization. The primary outcome was the incidence and impact of CA-AKI on MACCEs at 1 year follow-up. Out of 461 STEMI patients (mean age 88.6 ± 2.9 years), 102 (22.1%) patients developed CA-AKI. Chronic kidney disease was the strongest predictor of CA-AKI (odds ratio [OR]: 4.52, 95% CI: 2.81-7.30, P < .01). The CA-AKI cohort showed a higher risk of MACCEs (adjusted HR: 1.75, 95% CI: 1.13-2.71, P = .01), driven mainly by all-cause death (adjusted hazard ratio [HR]: 2.39, 95% CI: 1.41-4.07, P = .01) and followed by heart failure hospitalization (adjusted HR: 2.01, 95% CI: 1.08-3.76, P = .01). Among oldest old STEMI, CA-AKI was frequent and associated with a higher incidence of MACCEs at 1-year follow-up.

Noninvasive Advanced Cardiovascular Magnetic Resonance-Derived Fontan Hemodynamics Are Associated With Reduced Kidney Function But Not Albuminuria

BACKGROUND

Kidney disease is the most important predictor of death in patients with a Fontan circulation, yet its clinical and hemodynamic correlates have not been well established.

METHODS AND RESULTS

A total of 53 ambulatory patients with a Fontan circulation (median age, 16.2 years, 52.8% male patients) underwent advanced cardiovascular magnetic resonance assessment, including 4-dimensional flow imaging and computational fluid dynamics. Estimated glomerular filtration rate (eGFR) <90 mL/min per 1.73 m2 was observed in 20.8% and albumin-to-creatinine ratio >3 mg/mmol in 39.6%. The average eGFR decline rate was -1.83 mL/min per 1.73 m2 per year (95% CI, -2.67 to -0.99; P<0.001). Lower eGFR was associated with older age, larger body surface area at examination, longer time since Fontan procedure, and lower systemic ventricular ejection fraction. Higher albumin-to-creatinine ratio was associated with absence of fenestration at the Fontan operation, and older age and lower systemic ventricular ejection fraction at the assessment. Lower cross-sectional area of the Fontan conduit indexed to flow (r=0.32, P=0.038), higher inferior vena cava-conduit velocity mismatch factor (r=-0.35, P=0.022), higher kinetic energy indexed to flow in the total cavopulmonary connection (r=-0.59, P=0.005), and higher total cavopulmonary connection resistance (r=-0.42, P=0.005 at rest; r=-0.43, P=0.004 during exercise) were all associated with lower eGFR but not with albuminuria.

CONCLUSIONS

Kidney dysfunction and albuminuria are common among clinically well adolescents and young adults with a Fontan circulation. Advanced cardiovascular magnetic resonance-derived metrics indicative of declining Fontan hemodynamics are associated with eGFR and might serve as targets to improve kidney health. Albuminuria might be driven by other factors that need further investigation.

Urinary Marker Profiles in Heart Failure with Reduced Versus Preserved Ejection Fraction

BACKGROUND

Recent data suggest different causes of renal dysfunction between heart failure with reduced (HFrEF) versus preserved ejection fraction (HFpEF). We therefore studied a wide range of urinary markers reflecting different nephron segments in heart failure patients.

METHODS

In 2070, in chronic heart failure patients, we measured several established and upcoming urinary markers reflecting different nephron segments.

RESULTS

Mean age was 70 ± 12 years, 74% was male and 81% (n = 1677) had HFrEF. Mean estimated glomerular filtration rate (eGFR) was lower in patients with HFpEF (56 ± 23 versus 63 ± 23 ml/min/1.73 m2, P = 0.001). Patients with HFpEF had significantly higher values of NGAL (58.1 [24.0-124.8] versus 28.1 [14.6-66.9] μg/gCr, P < 0.001) and KIM-1 (2.28 [1.49-4.37] versus 1.79 [0.85-3.49] μg/gCr, P = 0.001). These differences were more pronounced in patients with an eGFR > 60 ml/min/1.73m2.

CONCLUSIONS

HFpEF patients showed more evidence of tubular damage and/or dysfunction compared with HFrEF patients, in particular when glomerular function was preserved.

Acute Kidney Injury: Definition, Management, and Promising Therapeutic Target

Acute kidney injury (AKI) is caused by a sudden loss of renal function, resulting in the build-up of waste products and a significant increase in mortality and morbidity. It is commonly diagnosed in critically ill patients, with its occurrence estimated at up to 50% in patients hospitalized in the intensive critical unit. Despite ongoing efforts, the death rate associated with AKI has remained high over the past half-century. Thus, it is critical to investigate novel therapy options for preventing the epidemic. Many studies have found that inflammation and Toll-like receptor-4 (TLR-4) activation have a significant role in the pathogenesis of AKI. Noteworthy, challenges in the search for efficient pharmacological therapy for AKI have arisen due to the multifaceted origin and complexity of the clinical history of people with the disease. This article focuses on kidney injury's epidemiology, risk factors, and pathophysiological processes. Specifically, it focuses on the role of TLRs especially type 4 in disease development.

Early changes in renal function during rapid up-titration of guideline-directed medical therapy following an admission for acute heart failure

AIM

In this subgroup analysis of STRONG-HF, we explored the association between changes in renal function and efficacy of rapid up-titration of guideline-directed medical therapy (GDMT) according to a high-intensity care (HIC) strategy.

METHODS AND RESULTS

In patients randomized to the HIC arm (n = 542), renal function was assessed at baseline and during follow-up visits. We studied the association with clinical characteristics and outcomes of a decrease in estimated glomerular filtration rate (eGFR) at week 1, defined as ≥15% decrease from baseline. Patients in the usual care group (n = 536) were seen at day 90. The treatment effect of HIC versus usual care was independent of baseline eGFR (p-interaction = 0.4809). A decrease in eGFR within 1 week occurred in 77 (15.5%) patients and was associated with more rales on examination (p = 0.004), and a higher New York Heart Association class at the corresponding visit. Following the decrease in eGFR at 1 week, lower average optimal doses of GDMT were prescribed during follow-up (p = 0.0210) and smaller reductions in N-terminal pro-B-type natriuretic peptide occurred (geometrical mean 0.81 in no eGFR decrease vs 1.12 in GFR decrease, p = 0.0003). The rate of heart failure (HF) readmission or death at 180 days was 12.3% in no eGFR decrease versus 18.5% in eGFR decrease (p = 0.2274) and HF readmissions were 7.8% versus 16.6% (p = 0.0496).

CONCLUSIONS

In the STRONG-HF study, HIC reduced 180-day HF readmission or death regardless of baseline eGFR. An early decrease in eGFR during rapid up-titration of GDMT was associated with more evidence of congestion, yet lower doses of GDMT during follow-up.

Correlation Between Cystatin C and the Severity of Cardiac Dysfunction in Patients with Systolic Heart Failure

Introduction

To investigate the relationship between cystatin C and cardiac dysfunction severity in patients with systolic heart failure.

Methods

We recruited 100 hospitalized patients with systolic heart failure and 100 age-gender-matched controls. The clinical information of each patient was collected. Blood pressure, heart rate, height, and weight were measured, as were serum concentrations of cholesterol, renal function indices, cystatin C, and B-type natriuretic peptide (BNP). Transthoracic echocardiography was performed on each patient.

Results

Cystatin C and other indices of renal function, such as urea nitrogen, creatinine, and uric acid, were significantly elevated in the serum of patients with heart failure and those with more severe cardiac dysfunction. The stepwise regression analyses showed that cystatin C was positively associated with BNP (β = 0.18, P = 0.04, 95% CI: 21.1 ~ 1420.4) and left atrial diameter (LAD) (β = 0.19, P = 0.04, 95% CI: 0.03 ~ 9.21) and was negatively associated with ejection fraction (β = -0.22, P = 0.023, 95% CI: -12.4 ~ -0.93), while creatinine was only positively correlated with BNP (β = 0.23, P = 0.03, 95% CI: 1.11 ~ 20.7). The Receiver Operating Characteristic (ROC) curves demonstrated significantly more severe cardiac dysfunction (NYHA III/IV) in patients with cystatin C ≥ 0.895mg/L (sensitivity was 83.0%, specificity was 80.9%, AUC = 0.893) and creatinine ≥ 91.5μmol/L (sensitivity was 71.7%, specificity was 70.2%, AUC = 0.764).

Conclusion

Cystatin C was significantly correlated with cardiac structure and function in patients with systolic heart failure, and it was more valuable than creatinine to evaluate the severity of heart failure.

Renal Outcomes Following Transcatheter Mitral Valve Repair - Analysis of COAPT Trial Data

The prevalence of valvular heart disease in the United States has been estimated at 4.2-to-5.6 million, with mitral regurgitation (MR) being the most common lesion. Significant MR is associated with heart failure (HF) and death if left untreated. When HF is present, renal dysfunction (RD) is common and is associated with worse outcomes (ie, it is a marker of HF disease progression). Additionally, a complex interplay exists in patients with HF who also have MR, as this combination further impairs renal function, and the presence of RD further worsens prognosis and often limits guideline-directed management and therapy (GDMT). This has important implications in secondary MR because GDMT is the standard of care. However, with the development of minimally invasive transcatheter mitral valve repair, mitral transcatheter edge-to-edge repair (TEER) has become a new treatment option for secondary MR that is now incorporated into current guidelines published in 2020 that listed mitral TEER as a class 2a recommendation (moderate recommendation with benefit >> risk) as an addition to GDMT in a subset of patients with left ventricular ejection fraction <50%. The Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation (COAPT) trial, which demonstrated favorable outcomes in secondary MR by adding mitral TEER to GDMT versus GDMT alone, was the evidence base for these guidelines. Considering these guidelines and the understanding that concomitant RD often limits GDMT in secondary MR, there is emerging research studying the renal outcomes from the COAPT trial. This review analyzes this evidence, which could further influence current decision-making and future guidelines.

Kidney function changes in acute heart failure: a practical approach to interpretation and management

Worsening kidney function (WKF) is common in patients with acute heart failure (AHF) syndromes. Although WKF has traditionally been associated with worse outcomes on a population level, serum creatinine concentrations vary greatly during episodes of worsening heart failure, with substantial individual heterogeneity in terms of their clinical meaning. Consequently, interpreting such changes within the appropriate clinical context is essential to unravel the pathophysiology of kidney function changes and appropriately interpret their clinical meaning. This article aims to provide a critical overview of WKF in AHF, aiming to provide physicians with some tips and tricks to appropriately interpret kidney function changes in the context of AHF.

The potential of cystatin C as a predictive biomarker in pulmonary hypertension

BACKGROUND

Cystatin C is a novel biomarker to identify renal dysfunction and cardiovascular risk.

OBJECTIVE

The aim of this study was to investigate the role of cystatin C in non-invasive risk prediction in a large cohort of patients with pre-capillary pulmonary hypertension (PH).

METHOD

We retrospectively analyzed pre-capillary PH patients with available cystatin C and hemodynamic data derived from right heart catheterization.

RESULTS

A total of 398 consecutive patients with confirmed pre-capillary PH were recruited from Fuwai Hospital between November 2020 and November 2021. Over a median duration of 282 days, 72 (18.1%) of these patients experienced clinical worsening. Cystatin C levels significantly correlated with cardiac index (r = -0.286, P < 0.001), mixed venous oxygen saturation (r = -0.216, P < 0.001), and tricuspid annular plane systolic excursion (r = -0.236, P < 0.001), and high cystatin C levels independently predicted a poor prognosis after adjusting potential confounders in different models (all P < 0.05). A three-group non-invasive risk model was constructed based on the combined assessment of the cystatin C and WHO-FC using dichotomous cut-off value. Those patients with higher cystatin C (≥ 1.0 mg/L) and a worse WHO-FC experienced the highest risk of endpoint occurrence. The predictive capacity of this model was comparable to that of an existing invasive risk stratification model (area under curve: 0.657 vs 0.643, P = 0.619).

CONCLUSIONS

Cystatin C levels were associated with disease severity and prognosis in patients with pre-capillary PH. A combination of high cystatin C and advanced WHO-FC identifies patients at particularly high risk of clinical deterioration.

Intrarenal Doppler ultrasonography in patients with HFrEF and acute decompensated heart failure undergoing recompensation

OBJECTIVES

Renal venous congestion due to backward heart failure leads to disturbance of renal function in acute decompensated heart failure (ADHF). Whether decongestion strategies have an impact on renal venous congestion is unknown. Objective was to evaluate changes in intrarenal hemodynamics using intrarenal Doppler ultrasonography (IRD) in patients with heart failure with reduced ejection fraction (HFrEF) and ADHF undergoing recompensation.

METHODS

Prospective observational study in patients with left ventricular ejection fraction (LV-EF) ≤ 35% hospitalized due to ADHF. IRD measurement was performed within the first 48 h of hospitalisation and before discharge. Decongestion strategies were based on clinical judgement according to heart failure guidelines. IRD was used to assess intrarenal venous flow (IRVF) pattern, venous impedance index (VII) and resistance index (RI). Laboratory analyses included plasma creatinine, eGFR and albuminuria.

RESULTS

A number of 35 patients with ADHF and LV-EF ≤ 35% were included into the study. IRD could be performed in 30 patients at inclusion and discharge. At discharge, there was a significant reduction of VII from a median of 1.0 (0.86-1.0) to 0.59 (0.26-1.0) (p < 0.01) as well as improvement of IRVF pattern categories (p < 0.05) compared to inclusion. Albuminuria was significantly reduced from a median of 78 mg/g creatinine (39-238) to 29 mg/g creatinine (16-127) (p = 0.02) and proportion of patients with normoalbuminuria increased (p = 0.01). Plasma creatinine and RI remained unchanged (p = 0.73; p = 0.43).

DISCUSSION

This is the first study showing an effect of standard ADHF therapy on parameters of renal venous congestion in patients with HFrEF and ADHF. Doppler sonographic evaluation of renal venous congestion might provide additional information to guide decongestion strategies in patients with ADHF.

Tricuspid Annular Plane Systolic Excursion/Systolic Pulmonary Artery Pressure Ratio and Cardiorenal Syndrome Type 2 in the Systemic Sclerosis EUSTAR Cohort

OBJECTIVE

The aim of the study was to evaluate the association between the tricuspid annular plane systolic excursion (TAPSE)/systolic pulmonary artery pressure (sPAP) ratio and estimated glomerular filtration rate (eGFR) and their association with mortality in the European Scleroderma Trials and Research (EUSTAR) cohort.

METHODS

Patients with systemic sclerosis (SSc) from the EUSTAR database with TAPSE, sPAP, and parameters required to calculate eGFR were included. Logistic regression and Cox regression analysis were performed to evaluate TAPSE/sPAP as a risk factor for chronic kidney disease (CKD) and overall survival.

RESULTS

A total of 2,370 patients with SSc were included; 284 (12%) patients had CKD stage 3a-5. TAPSE/sPAP (odds ratio [OR] 0.479; 95% CI 0.310-0.743; P < 0.001), arterial hypertension (OR 3.118; 95% CI 2.173-4.475; P < 0.001), diastolic dysfunction (OR 1.670; 95% CI 1.148-2.428; P < 0.01), and N-terminal pro-B-type natriuretic peptide (OR 1.165; 95% CI 1.041-1.304; P < 0.01) were associated with CKD stage 3a-5. TAPSE/sPAP ≤0.32 mm/mm Hg (hazard ratio [HR] 3.589; 95% CI 2.236-5.761; P < 0.001), eGFR <60 mL/min per 1.73 m2 (HR 2.818; 95% CI 1.777-4.468; P < 0.001), and age (HR 1.782; 95% CI 1.348-2.356; P < 0.001) were the most significant predictive factors for all-cause mortality. A total of 276 patients with SSc had pulmonary hypertension (PH) confirmed by right heart catheterization, with 69 (25%) having CKD stage 3a-5. No difference was found in eGFR between patients with PH with reduced or normal cardiac index.

CONCLUSION

Reduced TAPSE/sPAP ratio is independently associated with CKD. TAPSE/sPAP ratio ≤0.32 mm/mm Hg and eGFR <60 mL/min per 1.73 m2 are prognostic factors for all-cause mortality. In patients with SSc with PH, eGFR is independent by reduced cardiac output.

Pulmonary hypertension without heart failure causes cardiorenal syndrome in a porcine model

Cardiorenal syndromes type 1 and 2 are complex disorders in which cardiac dysfunction leads to kidney dysfunction. However, the mechanisms remain incompletely explained, during pulmonary hypertension in particular. The objective of this study is to develop an original preclinical model of cardiorenal syndrome secondary to a pulmonary hypertension in piglets. Twelve 2-month-old Large White piglets were randomized in two groups: (1) induction of pulmonary hypertension by ligation of the left pulmonary artery and iterative embolizations of the right lower pulmonary artery, or (2) Sham interventions. We evaluated the cardiac function using right heart catheterization, echocardiography and measurement of biochemistry markers). Kidney was characterized using laboratory blood and urine tests, histological evaluation, immunostainings for renal damage and repair, and a longitudinal weekly assessment of the glomerular filtration rate using creatinine-based estimation and intravenous injection of an exogenous tracer on one piglet. At the end of the protocol (6 weeks), the mean pulmonary artery pressure (32 ± 10 vs. 13 ± 2 mmHg; p = 0.001), pulmonary vascular resistance (9.3 ± 4.7 vs. 2.5 ± 0.4 WU; p = 0.004) and central venous pressure were significantly higher in the pulmonary hypertension group while the cardiac index was not different. Piglets with pulmonary hypertension had higher troponin I. We found significant tubular damage and an increase in albuminuria in the pulmonary hypertension group and negative correlation between pulmonary hypertension and renal function. We report here the first porcine model of cardiorenal syndrome secondary to pulmonary hypertension.

Acute kidney injury in patients with acute decompensated heart failure-cardiogenic shock: Prevalence, risk factors and outcome

BACKGROUND

Acute Kidney Injury (AKI) represents a major complication of acute heart failure and cardiogenic shock (CS). There is a paucity of data on AKI complicating acutely decompensated heart failure patients presenting with CS (ADHF-CS). We aimed to investigate AKI prevalence, risk factors and outcomes in this subgroup of patients.

METHODS

Retrospective observational study on patients admitted for ADHF-CS to our 12-bed Intensive Care Unit (ICU), between January 2010 and December 2019. Demographic, clinical, and biochemical variables were collected at baseline and during hospital stay.

RESULTS

Eighty-eight patients were consecutively recruited. The predominant etiologies were idiopathic dilated cardiomyopathy (47%), followed by post-ischemic (24%). AKI was diagnosed in 70 (79.5%) of patients. Forty-three out of 70 patients met the criteria for AKI at ICU admission. On multivariate analysis, a central venous pressure (CVP) higher than 10 mmHg (OR 3.9; 95%CI 1.2-12.6; p = 0.025) and serum lactate higher than 3 mmol/L (OR 4.1; 95%CI 1.01-16.3; p = 0.048) were identified to be independently associated with AKI. Age and AKI stage were independent predictors of 90-day mortality.

CONCLUSION

AKI is a common and early complication of ADHF-CS. Venous congestion and severe hypoperfusion are risk factors for AKI development. Early detection and prevention of AKI could lead to better outcome in this clinical subgroup.

New Insight in Cardiorenal Syndrome: From Biomarkers to Therapy

Cardiorenal syndrome consists in the coexistence of acute or chronic dysfunction of heart and kidneys resulting in a cascade of feedback mechanisms and causing damage to both organs associated with high morbidity and mortality. In the last few years, different biomarkers have been investigated with the aim to achieve an early and accurate diagnosis of cardiorenal syndrome, to provide a prognostic role and to guide the development of targeted pharmacological and non-pharmacological therapies. In such a context, sodium-glucose cotransporter 2 (SGLT2) inhibitors, recommended as the first-line choice in the management of heart failure, might represent a promising strategy in the management of cardiorenal syndrome due to their efficacy in reducing both cardiac and renal outcomes. In this review, we will discuss the current knowledge on the pathophysiology of cardiorenal syndrome in adults, as well as the utility of biomarkers in cardiac and kidney dysfunction and potential insights into novel therapeutics.

Role of the Renal Lymphatic System in Heart Failure

PURPOSE OF REVIEW

The lymphatic system plays a major but overlooked role in maintaining fluid homeostasis. Given the unique fluid homeostasis functions of the kidneys, dysregulation of the renal lymphatic system underlies the development of self-propagating congestive pathomechanisms. In this review, we outline the roles of the renal lymphatic system in heart failure (HF).

RECENT FINDINGS

Studies have uncovered several pathomechanisms involving the renal lymphatic system in congestive states, such as impaired interstitial draining by the renal lymphatic system, impaired structure and valves of renal lymphatics, lymphatic-induced increase in renal reabsorption of water and sodium, and development of albuminuria with proteinuria-induced renal lymphangiogenesis. These self-propagating mechanisms result in "renal tamponade" with manifestations of cardiorenal syndrome and inappropriate renal response to diuretics. Dysregulation of the renal lymphatic system is integral to the development and progression of congestion in HF. Targeting renal lymphatics may provide a novel pathway to treat intractable congestion.

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.

Pneumoperitoneum and Acute Kidney Injury-An Integrative Clinical Concept Review

An increased intraabdominal pressure, particularly when occurring during periods of hemodynamic instability or fluid overload, is regarded as a major contributor to acute kidney injury (AKI) in intensive care units. During abdominal laparoscopic procedures, intraoperative insufflation pressures up to 15 mmHg are applied, to enable visualization and surgical manipulation but with the potential to compromise net renal perfusion. Despite the widely acknowledged renal arterial autoregulation, net arterial perfusion pressure is known to be narrow, and the effective renal medullary perfusion is disproportionately impacted by venous and lymphatic congestion. At present, the potential risk factors, mitigators and risk-stratification of AKI during surgical pneumoperitoneum formation received relatively limited attention among nephrologists and represent an opportunity to look beyond mere blood pressure and intake-output balances. Careful charting and reporting duration and extent of surgical pneumoperitoneum represents an opportunity for anesthesia teams to better communicate intraoperative factors affecting renal outcomes for the postoperative clinical teams. In this current article, the authors are integrating preclinical data and clinical experience to provide a better understanding to optimize renal perfusion during surgeries. Future studies should carefully consider intrabdominal insufflation pressure as a key variable when assessing outcomes and blood pressure goals in these settings.

Association of Body Mass Index and Acute Kidney Injury Incidence and Outcome: A Systematic Review and Meta-Analysis

This study aims to provide pooled estimates for the incidence of acute kidney injury (AKI) in overweight, obese, and normal body mass index (BMI) patients, and to assess impact of BMI on mortality and chronic kidney disease (CKD) rates. We conducted literature search using online databases to analyze outcomes of BMI. This meta-analysis included 22 studies. Compared to normal BMI, underweight, overweight, or obese patients had higher risk of having AKI. Underweight individuals had 17% lower CKD risk (relative risk [RR]: 0.83, 95% confidence interval [CI]: 0.75, 0.90) while patients that were overweight (RR: 1.15, 95% CI: 1.08, 1.22) and obese (RR: 1.21, 95% CI: 1.10, 1.33) had higher risk of having CKD. Lower than normal BMI was associated with higher mortality risk (RR: 1.58, 95% CI: 1.35, 1.85), while being overweight or obese correlated with the decreased risk of mortality. An increased risk of AKI combined with an increased risk of mortality calls for renal protective strategies in subjects who are underweight at the time of hospital admission.

SGLT2 inhibitors in the treatment of type 2 cardiorenal syndrome: Focus on renal tubules

The pathogenesis of type 2 cardiorenal syndrome (CRS) is mostly associated with reduced cardiac output, increased central venous pressure (CVP), activation of the renin-angiotensin-aldosterone system (RAAS), inflammation, and oxidative stress. As a drug to treat diabetes, sodium-glucose transporter 2 inhibitor (SGLT2i) has been gradually found to have a protective effect on the heart and kidney and has a certain therapeutic effect on CRS. In the process of chronic heart failure (CHF) leading to chronic renal insufficiency, the renal tubular system, as the main functional part of the kidney, is the first to be damaged, but this damage can be reversed. In this review, we focus on the protective mechanisms of SGLT2i targeting renal tubular in the treatment of CRS, including natriuresis and diuresis to relieve renal congestion, attenuate renal tubular fibrosis, improve energy metabolism of renal tubular, and slow tubular inflammation and oxidative stress. This may have beneficial effects on the treatment of CRS and is a direction for future research.

Perirenal Fat and Kidney Function Deterioration in Patients With Acute Decompensated Heart Failure

BACKGROUND AND OBJECTIVES

The thick perirenal fat pad can induce high intracapsular pressure and cause compression of the renal vasculature and resultant congestive nephropathy. The current study investigated the association of perirenal fat thickness with kidney dysfunction in patients with acute decompensated heart failure (ADHF).

METHODS

Data from 266 patients hospitalized with ADHF were analyzed. Patients were divided into two groups according to the glomerular filtration rate (GFR) at admission (preserved kidney function [GFR ≥60 mL/min/1.73 m²] and reduced kidney function [GFR <60 mL/min/1.73 m²] groups). Right and left posterior perirenal fat thicknesses were measured using computed tomography, and their average values were calculated. Associated factors with reduced kidney function was assessed by logistic regression model, presenting with odds ratio (OR) and confidence interval (CI).

RESULTS

Increasing age (OR, 1.08; 95% CI, 1.04-1.12; p<0.001), diabetes mellitus (OR, 2.46; 95% CI, 1.18-5.12; p<0.017), increased log N-terminal pro-B-type natriuretic peptide (NT-proBNP) (OR, 1.82; 95% CI, 1.32-2.52; p<0.001), and increased average perirenal fat thickness (OR, 1.11; 95% CI, 1.06-1.16; p<0.001) were independently associated with reduced kidney function. In the subgroup analyses, patients over 70 years old, the ratio of mitral-to-mitral annular velocity >15, elevated log NT-proBNP had a significantly higher association with increased perirenal fat thickness with reduced kidney function.

CONCLUSIONS

Thick perirenal fat pads were independently associated with kidney function deterioration in patients hospitalized with ADHF.

Diuretic resistance in patients with kidney disease: Challenges and opportunities

Edema caused by kidney disease is called renal edema. Edema is a common symptom of many human kidney diseases. Patients with renal edema often need to take diuretics.However, After taking diuretics, patients with kidney diseases are prone to kidney congestion, decreased renal perfusion, decreased diuretics secreted by renal tubules, neuroendocrine system abnormalities, abnormal ion transporter transport, drug interaction, electrolyte disorder, and hypoproteinemia, which lead to ineffective or weakened diuretic use and increase readmission rate and mortality. The main causes and coping strategies of diuretic resistance in patients with kidney diseases were described in detail in this report. The common causes of DR included poor diet (electrolyte disturbance and hypoproteinemia due to patients' failure to limit diet according to correct sodium, chlorine, potassium, and protein level) and poor drug compliance (the patient did not take adequate doses of diuretics. true resistance occurs only if the patient takes adequate doses of diuretics, but they are not effective), changes in pharmacokinetics and pharmacodynamics, electrolyte disorders, changes in renal adaptation, functional nephron reduction, and decreased renal blood flow. Common treatment measures include increasing in the diuretic dose and/or frequency, sequential nephron blockade,using new diuretics, ultrafiltration treatment, etc. In clinical work, measures should be taken to prevent or delay the occurrence and development of DR in patients with kidney diseases according to the actual situation of patients and the mechanism of various causes. Currently, there are many studies on DR in patients with heart diseases. Although the phenomenon of DR in patients with kidney diseases is common, there is a relatively little overview of the mechanism and treatment strategy of DR in patients with kidney diseases. Therefore, this paper hopes to show the information on DR in patients with kidney diseases to clinicians and researchers and broaden the research direction and ideas to a certain extent.

Origins of abnormal placentation: why maternal veins must not be forgotten

The importance of uterine microvascular adaptations during placentation in pregnancy has been well established for decades. Inadequate dilatation of spiral arteries is associated with gestational complications, such as preeclampsia and/or intrauterine growth restriction. More recently, it has become clear that trophoblast cells invade and adapt decidual veins and lymphatic vessels 1 month before spiral arteries become patent and before intervillous space perfusion starts. Normal intervillous space hemodynamics is characterized by high volume flow at low velocity and pressure in the interseptal compartments surrounding the chorionic villi, hereby facilitating efficient maternal-fetal exchange. In case of shallow decidual vein dilatation, intervillous arterial supply exceeds venous drainage. This will cause congestion in the interseptal compartments with subsequently reduced perfusion and increased pressure. An efficient mechanism to counteract venous congestion and safeguard the viability of the conceptus is by reducing arterial inflow via shallow dilatation of the spiral arteries. This review made the case for intervillous space congestion as an unexplored trigger for inadequate spiral artery dilatation during the placentation process, eventually leading to abnormal systemic circulatory dysfunctions. An abnormal maternal venous function can result from an abnormal maternal immune response to paternal antigens with an imbalanced release of vasoactive mediators or can exist before conception. To get the full picture of abnormal placentation, maternal veins must not be forgotten.

Right Heart Function in Cardiorenal Syndrome

PURPOSE OF REVIEW

Since CRS is critically dependent on right heart function and involved in interorgan crosstalk, assessment and monitoring of both right heart and kidney function are of utmost importance for clinical outcomes. This systematic review aims to comprehensively report on novel diagnostic and therapeutic paradigms that are gaining importance for the clinical management of the growing heart failure population suffering from CRS.

RECENT FINDINGS

Cardiorenal syndrome (CRS) in patients with heart failure is associated with poor outcome. Although systemic venous congestion and elevated central venous pressure have been recognized as main contributors to CRS, they are often neglected in clinical practice. The delicate hemodynamic balance in CRS is particularly determined by the respective status of the right heart. The consideration of hemodynamic and CRS profiles is advantageous in tailoring treatment for better preservation of renal function. Assessment and monitoring of right heart and renal function by known and emerging tools like renal Doppler ultrasonography or new biomarkers may have direct clinical implications.

Renal Protection and Hemodynamic Improvement by Impella® Microaxial Pump in Patients with Cardiogenic Shock

Acute kidney injury is one of the most frequent and prognostically relevant complications in cardiogenic shock. The purpose of this study was to evaluate the potential effect of the Impella® pump on hemodynamics and renal organ perfusion in patients with myocardial infarction complicating cardiogenic shock. Between January 2020 and February 2022 patients with infarct-related cardiogenic shock supported with the Impella® pump were included in this single-center prospective short-term study. Changes in hemodynamics on different levels of Impella® support were documented with invasive pulmonal arterial catheter. As far as renal function is concerned, renal perfusion was assessed by determining the renal resistive index (RRI) using Doppler sonography. A total of 50 patients were included in the analysis. The increase in the Impella® output by a mean of 1.0 L/min improved the cardiac index (2.7 ± 0.86 to 3.3 ± 1.1 p < 0.001) and increased central venous oxygen saturation (62.6 ± 11.8% to 67.4 ± 10.5% p < 0.001). On the other side, the systemic vascular resistance (1035 ± 514 N·s/m5 to 902 ± 371 N·s/m5p = 0.012) and the RRI were significantly reduced (0.736 ± 0.07 to 0.62 ± 0.07 p < 0.001). Furthermore, in the overall cohort, a baseline RRI ≥ 0.8 was associated with a higher frequency of renal replacement therapy (71% vs. 39% p = 0.04), whereas the consequent reduction of the RRI below 0.7 during Impella® support improved the glomerular filtration rate (GFR) during hospital stay (15 ± 3 days; 53 ± 16 mL/min to 83 ± 16 mL/min p = 0.04). Impella® support in patients with cardiogenic shock seems to improve hemodynamics and renal organ perfusion. The RRI, a well-known parameter for the early detection of acute kidney injury, can be directly influenced by the Impella® flow rate. Thus, a targeted control of the RRI by the Impella® pump could mediate renal organ protection.

Postoperative central venous pressure is associated with acute kidney injury in patients undergoing coronary artery bypass grafting

Objective

The present study aimed to investigate the association of postoperative central venous pressure (CVP) with acute kidney injury (AKI) and mortality in patients undergoing coronary artery bypass grafting (CABG).

Method

Patients who underwent CABG in the MIMIC-III database were included and divided into two groups according to the optimal cutoff value of CVP for postoperative AKI determined by the receiver operating characteristic (ROC) curves. The association of CVP with AKI and mortality was determined by multivariate regression models. A 1:1 propensity score matching (PSM) was performed to balance the influence of potential confounding factors.

Results

A total of 3,564 patients were included and divided into High CVP group (CVP ≥ 10.9 mmHg) and Low CVP group (CVP &lt; 10.9 mmHg) according to the ROC analysis. Patients in High CVP group presented with higher AKI incidence (420 (28.2%) vs. 349 (16.8), p &lt; 0.001), in-hospital mortality (28 (1.9%) vs. 6 (0.3%), p &lt; 0.001) and 4-year mortality (149 (15.8%) vs. 162 (11.1%), p = 0.001). Multivariate regression model showed that CVP was an independent risk factor for the postoperative AKI (OR: 1.071 (1.035, 1.109), p &lt; 0.001), in-hospital mortality (OR: 1.187 (1.026, 1.373), p = 0.021) and 4-year mortality (HR: 1.049 (1.003, 1.096), p = 0.035). A CVP above 10.9 mmHg was significantly associated with about 50% higher risk of AKI (OR: 1.499 (1.231, 1.824), p &lt; 0.001). After PSM, 1004 pairs of score-matched patients were generated. The multivariate logistic model showed that patients with CVP ≥ 10.9 mmHg had a significantly higher risk of AKI (OR: 1.600 (1.268, 2.018), p &lt; 0.001) in the PSM subset. However, CVP, as a continuous or a dichotomic variable, was not independently associated with in-hospital mortality (OR: 1.202 (0.882, 1.637), p = 0.244; OR: 2.636 (0.399, 17.410), p = 0.314) and 4-year mortality (HR: 1.030 (0.974, 1.090), p = 0.297; HR: 1.262 (0.911, 1.749), p = 0.162) in the PSM dataset.

Conclusion

A mean CVP ≥ 10.9 mmHg within the first 24 h after CABG was independently associated with a higher risk of postoperative AKI.

Comparing the associations of central venous pressure and pulmonary artery pulsatility index with postoperative renal injury

Objective

Cardiac surgery-associated acute kidney injury (CS-AKI) is associated with significant morbidity and mortality. We investigated the association of postoperative central venous pressure (CVP) and pulmonary artery pulsatility index (PAPi) with the development of CS-AKI.

Methods

This was a single-center, retrospective cohort study of patients undergoing cardiac surgery. CVP and PAPi were acquired hourly postoperatively and averaged for up to 48 h. PAPi was calculated as [(Pulmonary Artery Systolic Pressure–Pulmonary Artery Diastolic Pressure) / CVP]. The primary aim was CS-AKI. Secondary aims were need for renal replacement therapy (RRT), hospital and 30-day mortality, total ventilator and intensive care unit hours, and hospital length of stay. Logistic regression was used to calculate odds of development of renal injury and need for RRT.

Results

One thousand two hundred eighty-eight patients were included. The average postoperative CVP was 10.3 mmHg and average postoperative PAPi was 2.01. Patients who developed CS-AKI (n = 384) had lower PAPi (1.79 vs. 2.11, p < 0.01) and higher CVP (11.5 vs. 9.7 mmHg, p < 0.01) than those who did not. Lower PAPi and higher CVP were also associated with each secondary aim. A standardized unit decrease in PAPi was associated with increased odds of CS-AKI (OR 1.39, p < 0.01) while each unit increase in CVP was associated with both increased odds of CS-AKI (OR 1.56, p < 0.01) and postoperative RRT (OR 1.49, p = 0.02).

Conclusions

Both lower PAPi and higher CVP values postoperatively were associated with the development of CS-AKI but only higher CVP was associated with postoperative RRT use. When differences in values are standardized, CVP may be more associated with development of CS-AKI when compared to PAPi.

Arteriovenous Fistulae in Chronic Kidney Disease and the Heart: Physiological, Histological, and Transcriptomic Characterization of a Novel Rat Model

Background Arteriovenous fistulae (AVFs) are the gold standard for vascular access in those requiring hemodialysis but may put an extra hemodynamic stress on the cardiovascular system. The complex interactions between the heart, kidney, and AVFs remain incompletely understood. Methods and Results We characterized a novel rat model of five-sixths partial nephrectomy (NX) and AVFs. NX induced increases in urea, creatinine, and hippuric acid. The addition of an AVF (AVF+NX) further increased urea and a number of uremic toxins such as trimethylamine N-oxide and led to increases in cardiac index, left and right ventricular volumes, and right ventricular mass. Plasma levels of uremic toxins correlated well with ventricular morphology and function. Heart transcriptomes identified altered expression of 8 genes following NX and 894 genes following AVF+NX, whereas 290 and 1431 genes were altered in the kidney transcriptomes, respectively. Gene ontology and Kyoto Encyclopedia of Genes and Genomes analysis revealed gene expression changes related to cell division and immune activation in both organs, suppression of ribosomes and transcriptional activity in the heart, and altered renin-angiotensin signaling as well as chronodisruption in the kidney. All except the latter were worsened in AVF+NX compared with NX. Conclusions Inflammation and organ dysfunction in chronic kidney disease are exacerbated following AVF creation. Furthermore, our study provides important information for the discovery of novel biomarkers and therapeutic targets in the management of cardiorenal syndrome.

Cardiorenal Interactions: A Review

A complex interaction occurs between cardiac and renal function. They are intricately tied together, and a range of disorders in both the heart and kidneys can alter the function of the other. The pathophysiology is complex, and these conditions are termed cardiorenal syndromes. They can be acute and/or chronic in nature, they result in and from hemodynamic consequences, systemic congestion, and metabolic abnormalities, and they lead to dysfunction of both the heart and kidneys. The aim of this article is to provide a review for cardiologists and intensivists who are treating patients for whom cardiac and renal interactions may complicate their picture. We review acute kidney injuries, management of the complications of renal dysfunction, renal replacement therapy, and cardiorenal syndromes.

Edema formation in congestive heart failure and the underlying mechanisms

Congestive heart failure (HF) is a complex disease state characterized by impaired ventricular function and insufficient peripheral blood supply. The resultant reduced blood flow characterizing HF promotes activation of neurohormonal systems which leads to fluid retention, often exhibited as pulmonary congestion, peripheral edema, dyspnea, and fatigue. Despite intensive research, the exact mechanisms underlying edema formation in HF are poorly characterized. However, the unique relationship between the heart and the kidneys plays a central role in this phenomenon. Specifically, the interplay between the heart and the kidneys in HF involves multiple interdependent mechanisms, including hemodynamic alterations resulting in insufficient peripheral and renal perfusion which can lead to renal tubule hypoxia. Furthermore, HF is characterized by activation of neurohormonal factors including renin-angiotensin-aldosterone system (RAAS), sympathetic nervous system (SNS), endothelin-1 (ET-1), and anti-diuretic hormone (ADH) due to reduced cardiac output (CO) and renal perfusion. Persistent activation of these systems results in deleterious effects on both the kidneys and the heart, including sodium and water retention, vasoconstriction, increased central venous pressure (CVP), which is associated with renal venous hypertension/congestion along with increased intra-abdominal pressure (IAP). The latter was shown to reduce renal blood flow (RBF), leading to a decline in the glomerular filtration rate (GFR). Besides the activation of the above-mentioned vasoconstrictor/anti-natriuretic neurohormonal systems, HF is associated with exceptionally elevated levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). However, the supremacy of the deleterious neurohormonal systems over the beneficial natriuretic peptides (NP) in HF is evident by persistent sodium and water retention and cardiac remodeling. Many mechanisms have been suggested to explain this phenomenon which seems to be multifactorial and play a major role in the development of renal hyporesponsiveness to NPs and cardiac remodeling. This review focuses on the mechanisms underlying the development of edema in HF with reduced ejection fraction and refers to the therapeutic maneuvers applied today to overcome abnormal salt/water balance characterizing HF.

Mechanistic Insights in Cardiorenal Syndrome

Mechanistic Insights in Cardiorenal SyndromeLo and Rangaswami review the pathophysiology and management of cardiorenal syndrome, with a focus on decongestion, interpretation of kidney function, and implementation of guideline directed medical therapies.

Risk Factors for Postoperative Acute Kidney Injury in Patients Undergoing Redo Cardiac Surgery Using Cardiopulmonary Bypass

Objective: This paper aimed to investigate the incidence and risk factors of postoperative acute kidney injury (AKI) in adult patients undergoing redo cardiac surgery with cardiopulmonary bypass (CPB), and explore the impact of AKI on early outcomes. Methods: A total of 116 patients undergoing redo cardiac surgery with CPB between November 2017 and May 2021 were included. Patients were divided into two groups, AKI group and non-AKI group, according to the Kidney Disease Improving Global Outcomes criteria. Perioperative variables were retrospectively collected and analyzed. Risk factors for the development of AKI were investigated by univariate and multiple logistic regression models. Clinical outcomes were also compared between the groups. Results: Postoperative AKI occurred in 63 patients (54.3%), among whom renal replacement therapy was required in 12 patients (19.0%). The mechanical ventilation time (AKI: 43.00 (19.00, 72.00) hours; non-AKI: 18.00 (15.00, 20.00) hours; p < 0.001), ICU length of stay (AKI: 4.00 (2.00, 6.00) days; non-AKI: 3.00 (2.00, 4.00) days; p = 0.010), hospital length of stay since operation (AKI: 12.00 (8.00, 18.00) days; non-AKI: 9.00 (7.00, 12.50) days; p = 0.024), dialysis (AKI: 12.00 (19.05%); non-AKI: 0 (0%); p = 0.001), reintubation (AKI: 7.00 (11.11%); non-AKI: 0 (0%); p = 0.035), and hospital mortality (AKI: 8.00 (12.70%); non-AKI: 0 (0%); p = 0.020) were all higher in the AKI group than in the non-AKI group. Multivariate analysis revealed that high aspartate aminotransferase (OR, 1.028, 95% CI, 1.003 to 1.053, p = 0.025), coronary angiogram within 2 weeks before surgery (OR, 3.209, 95% CI, 1.307 to 7.878, p = 0.011) and CPB time (OR, 1.012, 95% CI, 1.005 to 1.019, p = 0.001) were independent risk factors for postoperative AKI. Conclusions: High aspartate aminotransferase, coronary angiogram within 2 weeks before surgery and CPB time seem to be associated with an increased incidence of postoperative AKI in patients with redo cardiac surgery.

BESTFIT-T3: A Tiered Monitoring Approach to Persistent/Recurrent Paediatric Septic Shock - A Pilot Conceptual Report

Objective

Persistent shock (PS) or recurrent shock (RS) after initial fluids and vasoactives can be secondary to myriad complex mechanisms, and these patients can have a high mortality. We developed a noninvasive tiered hemodynamic monitoring approach which included, in addition to basic echocardiography, cardiac output monitoring and advanced Doppler studies to determine the etiology and provide targeted therapy of PS/RS.

Design

Prospective observational study.

Setting

Tertiary Care Pediatric Intensive Care Unit, India.

Methods

A pilot conceptual report describing the clinical presentation of 10 children with PS/RS using advanced ultrasound and noninvasive cardiac output monitoring. Children with PS/RS after initial fluids and vasoactive agents despite basic echocardiography underwent BESTFIT + T3 (Basic Echocardiography in Shock Therapy for Fluid and Inotrope Titration) with lung ultrasound and advanced 3-tiered monitoring (T1-3).

Results

Among 10/53 children with septic shock and PS/RS over a 24-month study period, BESTFIT + T3 revealed combinations of right ventricular dysfunction, diastolic dysfunction (DD), altered vascular tone, and venous congestion (VC). By integrating information obtained by BESTFIT + T1-3 and the clinical context, we were able to modify the therapeutic regimen and successfully reverse shock in 8/10 patients.

Conclusion

We present our pilot results with BESTFIT + T3, a novel approach that can noninvasively interrogate major cardiac, arterial, and venous systems that may be particularly useful in regions where expensive rescue therapies are out of reach. We suggest that, with practice, intensivists already experienced in bedside POCUS can use the information obtained by BESTFIT + T3 to direct time-sensitive precision cardiovascular therapy in persistent/recurrent pediatric septic shock.

How to cite this article

Natraj R, Ranjit S. BESTFIT-T3: A Tiered Monitoring Approach to Persistent/Recurrent Paediatric Septic Shock - A Pilot Conceptual Report. Indian J Crit Care Med 2022;26(7):863-870.

Impact of mean perfusion pressure and vasoactive drugs on occurrence and reversal of cardiac surgery-associate acute kidney injury: A cohort study

PURPOSE

Low cardiac output and kidney congestion are associated with acute kidney injury after cardiac surgery (CSA-AKI). This study investigates hemodynamics on CSA-AKI development and reversal.

MATERIALS AND METHODS

Adult patients undergoing cardiac surgery were retrospectively included. Hemodynamic support was quantified using a new time-weighted vaso-inotropic score (VIS_AUC), and hemodynamic variables expressed by mean perfusion pressure and its components. The primary outcome was AKI stage ≥2 (CSA-AKI ≥2) and secondary outcome full AKI reversal before ICU discharge.

RESULTS

3415 patients were included. CSA-AKI ≥2 occurred in 37.4%. Mean perfusion pressure (MPP) (OR 0.95,95%CI 0.94-0.96, p < 0.001); and central venous pressure (CVP) (OR 1.17, 95%CI 1.13-1.22, p < 0.001) are associated with CSA-AKI ≥2 development, while VIS_AUC/h was not (p = 0.104). Out of 1085 CSA-AKI ≥2 patients not requiring kidney replacement therapy, 76.3% fully recovered of AKI. Full CSA-AKI reversal was associated with MPP (OR 1.02 per mmHg (95%CI 1.01-1.03, p = 0.003), and MAP (OR = 1.01 per mmHg (95%CI 1.00-1.02), p = 0.047), but not with VIS_AUC/h (p = 0.461).

CONCLUSION

Development and full recovery of CSA-AKI ≥2 are affected by mean perfusion pressure, independent of vaso-inotropic use. CVP had a significant effect on AKI development, while MAP on full AKI reversal.

Machine learning to predict post-operative acute kidney injury stage 3 after heart transplantation

BACKGROUND

Acute kidney injury (AKI) stage 3, one of the most severe complications in patients with heart transplantation (HT), is associated with substantial morbidity and mortality. We aimed to develop a machine learning (ML) model to predict post-transplant AKI stage 3 based on preoperative and perioperative features.

METHODS

Data from 107 consecutive HT recipients in the provincial center between 2018 and 2020 were included for analysis. Logistic regression with L2 regularization was used for the ML model building. The predictive performance of the ML model was assessed using the area under the curve (AUC) in tenfold stratified cross-validation and was compared with that of the Cleveland-clinical model.

RESULTS

Post-transplant AKI occurred in 76 (71.0%) patients including 15 (14.0%) stage 1, 18 (16.8%) stage 2, and 43 (40.2%) stage 3 cases. The top six features selected for the ML model to predicate AKI stage 3 were serum cystatin C, estimated glomerular filtration rate (eGFR), right atrial long-axis dimension, left atrial anteroposterior dimension, serum creatinine (SCr) and FVII. The predictive performance of the ML model (AUC: 0.821; 95% confidence interval [CI]: 0.740-0.901) was significantly higher compared with that of the Cleveland-clinical model (AUC: 0.654; 95% [CI]: 0.545-0.763, p < 0.05).

CONCLUSIONS

The ML model, which achieved an effective predictive performance for post-transplant AKI stage 3, may be helpful for timely intervention to improve the patient's prognosis.

Association between central haemodynamics and renal function in advanced heart failure: a nationwide study from Sweden

AIMS

Renal dysfunction in patients with heart failure (HF) has traditionally been attributed to declining cardiac output and renal hypoperfusion. However, other central haemodynamic aberrations may contribute to impaired kidney function. This study assessed the relationship between invasive central haemodynamic measurements from right-heart catheterizations and measured glomerular filtration rate (mGFR) in advanced HF.

METHODS AND RESULTS

All patients referred for heart transplantation work-up in Sweden between 1988 and 2019 were identified through the Scandiatransplant organ-exchange organization database. Invasive haemodynamic variables and mGFR were retrieved retrospectively. A total of 1001 subjects (49 ± 13 years; 24% female) were eligible for the study. Analysis of covariance adjusted for age, sex, and centre revealed that higher right atrial pressure (RAP) displayed the strongest relationship with impaired GFR [β coefficient -0.59; 95% confidence interval (CI) -0.69 to -0.48; P < 0.001], followed by lower mean arterial pressure (MAP) (β coefficient 0.29; 95% CI 0.14-0.37; P < 0.001), and finally reduced cardiac index (β coefficient 3.51; 95% CI 2.14-4.84; P < 0.003). A combination of high RAP and low MAP was associated with markedly worse mGFR than any other RAP/MAP profile, and high renal perfusion pressure (RPP, MAP minus RAP) was associated with superior renal function irrespective of the degree of cardiac output.

CONCLUSIONS

In patients with advanced HF, high RAP contributed more to impaired GFR than low MAP. A higher RPP was more closely related to GFR than was high cardiac index.

Mediators of Regional Kidney Perfusion during Surgical Pneumo-Peritoneum Creation and the Risk of Acute Kidney Injury—A Review of Basic Physiology

Acute kidney injury (AKI), especially if recurring, represents a risk factor for future chronic kidney disease. In intensive care units, increased intra-abdominal pressure is well-recognized as a significant contributor to AKI. However, the importance of transiently increased intra-abdominal pressures procedures is less commonly appreciated during laparoscopic surgery, the use of which has rapidly increased over the last few decades. Unlike the well-known autoregulation of the renal cortical circulation, medulla perfusion is modulated via partially independent regulatory mechanisms and strongly impacted by changes in venous and lymphatic pressures. In our review paper, we will provide a comprehensive overview of this evolving topic, covering a broad range from basic pathophysiology up to and including current clinical relevance and examples. Key regulators of oxidative stress such as ischemia-reperfusion injury, the activation of inflammatory response and humoral changes interacting with procedural pneumo-peritoneum formation and AKI risk will be recounted. Moreover, we present an in-depth review of the interaction of pneumo-peritoneum formation with general anesthetic agents and animal models of congestive heart failure. A better understanding of the relationship between pneumo-peritoneum formation and renal perfusion will support basic and clinical research, leading to improved clinical care and collaboration among specialists.