Cystatin C- Versus Creatinine-Based Assessment of Renal Function and Prediction of Early Outcomes Among Patients With a Left Ventricular Assist Device

Pre-operative pectoralis muscle area index is associated with biomarkers of inflammation and endotoxemia and predicts clinical outcomes after left ventricular assist device implantation: A cohort study

BACKGROUND

Pre-left ventricular assist device (LVAD) pectoralis muscle assessment, an estimate of sarcopenia, has been associated with postoperative mortality and gastrointestinal bleeding, though its association with inflammation, endotoxemia, length-of-stay (LOS), and readmissions remains underexplored.

METHODS

This was a single-center cohort study of LVAD patients implanted 1/2015-10/2018. Preoperative pectoralis muscle area was measured on chest computed tomography (CT), adjusted for height squared to derive pectoralis muscle area index (PMI). Those with PMI in the lowest quintile were defined as low-PMI cohort; all others constituted the reference cohort. Biomarkers of inflammation (interleukin-6, adiponectin, tumor necrosis factor-α [TNFα]) and endotoxemia (soluble (s)CD14) were measured in a subset of patients.

RESULTS

Of the 254 LVAD patients, 95 had a preoperative chest CT (median days pre-LVAD: 7 [IQR 3-13]), of whom 19 (20.0%) were in the low-PMI cohort and the remainder were in the reference cohort. Compared with the reference cohort, the low-PMI cohort had higher levels of sCD14 (2594 vs. 1850 ng/mL; p = 0.04) and TNFα (2.9 vs. 1.9 pg/mL; p = 0.03). In adjusted analyses, the low-PMI cohort had longer LOS (incidence rate ratio 1.56 [95% confidence interval 1.16-2.10], p = 0.004) and higher risk of 90-day and 1-year readmissions (subhazard ratio 5.48 [1.88-16.0], p = 0.002; hazard ratio 1.73 [1.02-2.94]; p = 0.04, respectively).

CONCLUSIONS

Pre-LVAD PMI is associated with inflammation, endotoxemia, and increased LOS and readmissions.

Kidney function assessment using cystatin C and serum creatinine in heart transplantation recipients: Implications for valganciclovir dosing

BACKGROUND

Among heart transplantation (HT) recipients, the accuracy of serum creatinine (sCr)-based estimated glomerular filtration rate (eGFR) may be limited by fluctuations in muscle mass. Cystatin C (cysC) is less influenced by muscle mass, but its levels may increase with obesity and steroid use. Herein, we (1) longitudinally compared eGFRcysC and eGFRsCr among HT recipients; (2) investigated the association of body mass index (BMI), steroid use, and muscle mass with discrepancies between eGFRs; and (3) explored the implications of eGFRcysC use on valganciclovir (VGC) dosing.

METHODS

cysC and sCr were measured in 294 blood samples obtained from 80 subjects. Intraindividual differences between eGFRs (eGFRdiffcysC-sCr) were calculated with negative values corresponding to eGFRsCr > eGFRcysC and positive values to eGFRcysC > eGFRsCr. In a patient subset (n = 21), pectoralis muscle measures were obtained.

RESULTS

Marked differences between eGFRcysC and eGFRsCr were observed, particularly early post-HT (1-week post-HT, median eGFRdiffcysC-sCr -28 ml/min/1.73 m2). eGFRcysC demonstrated stability following a transient postoperative decline, while eGFRsCr decreased in the first year post-HT. Lower BMI and higher prednisone dose displayed a modest association with more negative eGFRdiffcysC-sCr values. Pectoralis muscle measures indicative of greater muscle mass and better tissue quality exhibited a stronger association with more positive eGFRdiffcysC-sCr values. The use of eGFRcysC would have led to VGC dose adjustment in 46% of samples, predominantly resulting in dose reduction.

CONCLUSIONS

Among HT recipients, eGFRcysC and eGFRsCr markedly differ with implications for VGC dosing. The observed discrepancies may reflect changes in body composition and steroid use.

Association of suPAR, ST2, and galectin-3 with eGFR decline and mortality in patients with advanced heart failure with reduced ejection fraction

Patients with heart failure with reduced ejection fraction (HFrEF) are at risk for chronic kidney disease (CKD). Elevated levels of circulating biomarkers soluble urokinase plasminogen activator receptor (suPAR), galectin-3, soluble suppression of tumorigenicity 2 (ST2), and N-terminal prohormone B-type natriuretic peptide (NT-proBNP) are associated with CKD progression and mortality. The predictive value of these biomarkers in a population with HFrEF and kidney disease is relatively unknown. We sought to determine whether these biomarkers were associated with longitudinal trajectory of estimated glomerular filtration rate (eGFR) in HFrEF and assess their association with mortality using a joint model to account for competing risks of ventricular assist device (VAD) implantation and heart transplantation. We included participants from the Registry Evaluation of Vital Information for Ventricular Assist Devices in Ambulatory Life with repeated eGFR measures over 2 years. Of 309 participants, mean age was 59 years, median eGFR 60 ml/min/1.73 m2, 45 participants died, 33 received VAD, and 25 received orthotopic heart transplantation. Higher baseline serum standardized suPAR (β coefficient = -0.36 √(ml/min/1.73 m2), 95% confidence interval (-0.48 to -0.24), p < 0.001), standardized galectin-3 (-0.14 √(ml/min/1.73 m2) (-0.27 to -0.02), p = 0.02), and log NT-proBNP (-0.23 √(ml/min/1.73 m2) (-0.31 to -0.15), p < 0.001) were associated with eGFR decline. ST2 and log NT-proBNP were associated with mortality. Higher baseline suPAR, galectin-3, and NT-proBNP are associated with eGFR decline in patients with HFrEF. Only ST2 and NT-proBNP are associated with greater mortality after controlling for other factors including change in eGFR. These biomarkers may provide prognostic value for kidney disease progression in HFrEF and inform candidacy for advanced heart failure therapies.

Controversies and Conundrums in Cardiac Cachexia: Key Questions About Wasting in Patients With HFrEF

Cardiac cachexia is characterized by unintentional catabolic weight loss, decreased appetite, and inflammation and is common in patients with stage D (advanced) heart failure with reduced ejection fraction (HFrEF). Cardiac cachexia and related muscle-wasting syndromes are markers of, and a consequence of, the heart failure (HF) syndrome. Although many potential modalities for identifying cardiac cachexia exist, the optimal definition, diagnostic tools, and treatment options for cardiac cachexia remain unclear. Furthermore, it remains unclear whether attempts to reverse muscle wasting prior to advanced HF surgeries, such as left ventricular assist devices and heart transplantation, can improve outcomes. It is important that HF clinicians and dietitians are aware of the pathophysiology and mechanisms of muscle-wasting syndromes in patients with HF, to aid in the recognition and risk stratification of advanced HFrEF. Although the opportunities and rationale for attempting to address cardiac cachexia prior to advanced HF surgeries are uncertain, recent publications suggest that control of the neurohumoral syndrome of advanced HF may be important to permit the recovery of skeletal muscle mass.

Alterations in the sarcopenia index are associated with inflammation, gut, and oral microbiota among heart failure, left ventricular assist device, and heart transplant patients

BACKGROUND

Sarcopenia, characterized by loss of muscle mass and function, is prevalent in heart failure (HF) and predicts poor outcomes. We investigated alterations in sarcopenia index (SI), a surrogate for skeletal muscle mass, in HF, left ventricular assist device (LVAD), and heart transplant (HT), and assessed its relationship with inflammation and digestive tract (gut and oral) microbiota.

METHODS

We enrolled 460 HF, LVAD, and HT patients. Repeated measures pre/post-procedures were obtained prospectively in a subset of LVAD and HT patients. SI (serum creatinine/cystatin C) and inflammatory biomarkers (C-reactive protein, interleukin-6, tumor necrosis factor-alpha) were measured in 271 and 622 blood samples, respectively. Gut and saliva microbiota were assessed via 16S ribosomal ribonucleic acid sequencing among 335 stool and 341 saliva samples. Multivariable regression assessed the relationship between SI and (1) New York Heart Association class; (2) pre- versus post-LVAD or HT; and (3) biomarkers of inflammation and microbial diversity.

RESULTS

Median (interquartile range) natural logarithm (ln)-SI was -0.13 (-0.32, 0.05). Ln-SI decreased across worsening HF class, further declined at 1 month after LVAD and HT, and rebounded over time. Ln-SI was correlated with inflammation (r = -0.28, p < 0.01), gut (r = 0.28, p < 0.01), and oral microbial diversity (r = 0.24, p < 0.01). These associations remained significant after multivariable adjustment in the combined cohort but not for all individual cohorts. The presence of the gut taxa Roseburia inulinivorans was associated with increased SI.

CONCLUSIONS

SI levels decreased in symptomatic HF and remained decreased long-term after LVAD and HT. In the combined cohort, SI levels covaried with inflammation in a similar fashion and were significantly related to overall microbial (gut and oral) diversity, including specific taxa compositional changes.

The Need to Identify Novel Markers for Early Renal Injury in Cardiorenal Syndrome

The term "Cardiorenal Syndrome" (CRS) refers to the complex interplay between heart and kidney dysfunction. First described by Robert Bright in 1836, CRS was brought to its modern view by Ronco et al. in 2008, who defined it as one organ's primary dysfunction leading to secondary dysfunction in the other, a view that led to the distinction of five different types depending on the organ of primary dysfunction and the temporal pattern (acute vs. chronic). Their pathophysiology is intricate, involving various hemodynamic, neurohormonal, and inflammatory processes that result in damage to both organs. While traditional biomarkers have been utilized for diagnosing and prognosticating CRS, they are inadequate for the early detection of acute renal damage. Hence, there is a pressing need to discover new biomarkers to enhance clinical outcomes and treatment approaches.

Right heart failure after durable left ventricular assist device implantation

INTRODUCTION

Right heart failure (RHF) is a well-known complication after left ventricular assist device (LVAD) implantation and portends increased morbidity and mortality. Understanding the mechanisms and predictors of RHF in this clinical setting may offer ideas for early identification and aggressive management to minimize poor outcomes. A variety of medical therapies and mechanical circulatory support options are currently available for the management of post-LVAD RHF.

AREAS COVERED

We reviewed the existing definitions of RHF including its potential mechanisms in the context of durable LVAD implantation and currently available medical and device therapies. We performed a literature search using PubMed (from 2010 to 2023).

EXPERT OPINION

RHF remains a common complication after LVAD implantation. However, existing knowledge gaps limit clinicians' ability to adequately address its consequences. Early identification and management are crucial to reducing the risk of poor outcomes, but existing risk stratification tools perform poorly and have limited clinical applicability. This is an area ripe for investigation with the potential for major improvements in identification and targeted therapy in an effort to improve outcomes.

The Difference Between Cystatin C- and Creatinine-Based Estimated GFR in Heart Failure With Reduced Ejection Fraction: Insights From PARADIGM-HF

RATIONALE & OBJECTIVE

The clinical implications of the discrepancy between cystatin C (cysC)- and serum creatinine (Scr)-estimated glomerular filtration rate (eGFR) in patients with heart failure (HF) and reduced ejection fraction (HFrEF) are unknown.

STUDY DESIGN

Post-hoc analysis of randomized trial data.

SETTING & PARTICIPANTS

1,970 patients with HFrEF enrolled in PARADIGM-HF with available baseline cysC and Scr measurements.

EXPOSURE

Intraindividual differences between eGFR based on cysC (eGFRcysC) and Scr (eGFRScr; eGFRdiffcysC-Scr).

OUTCOMES

Clinical outcomes included the PARADIGM-HF primary end point (composite of cardiovascular [CV] mortality or HF hospitalization), CV mortality, all-cause mortality, and worsening kidney function. We also examined poor health-related quality of life (HRQoL), frailty, and worsening HF (WHF), defined as HF hospitalization, emergency department visit, or outpatient intensification of therapy between baseline and 8-month follow-up.

ANALYTICAL APPROACH

Fine-Gray subdistribution hazard models and Cox proportional hazards models were used to regress clinical outcomes on baseline eGFRdiffcysC-Scr. Logistic regression was used to investigate the association of baseline eGFRdiffcysC-Scr with poor HRQoL and frailty. Linear regression models were used to assess the association of WHF with eGFRcysC, eGFRScr, and eGFRdiffcysC-Scr at 8-month follow-up.

RESULTS

Baseline eGFRdiffcysC-Scr was higher than +10 and lower than-10mL/min/1.73m2 in 13.0% and 35.7% of patients, respectively. More negative values of eGFRdiffcysC-Scr were associated with worse outcomes ([sub]hazard ratio per standard deviation: PARADIGM-HF primary end point, 1.18; P=0.008; CV mortality, 1.34; P=0.001; all-cause mortality, 1.39; P<0.001; worsening kidney function, 1.31; P=0.05). For a 1-standard-deviation decrease in eGFRdiffcysC-Scr, the prevalences of poor HRQoL and frailty increased by 29% and 17%, respectively (P≤0.008). WHF was associated with a more pronounced decrease in eGFRcysC than in eGFRScr, resulting in a change in 8-month eGFRdiffcysC-Scr of-4.67mL/min/1.73m2 (P<0.001).

LIMITATIONS

Lack of gold-standard assessment of kidney function.

CONCLUSIONS

In patients with HFrEF, discrepancies between eGFRcysC and eGFRScr are common and are associated with clinical outcomes, HRQoL, and frailty. The decline in kidney function associated with WHF is more marked when assessed with eGFRcysC than with eGFRScr.

PLAIN-LANGUAGE SUMMARY

Kidney function assessment traditionally relies on serum creatinine (Scr) to establish an estimated glomerular filtration rate (eGFR). However, this has been challenged with the introduction of an alternative marker, cystatin C (cysC). Muscle mass and nutritional status have differential effects on eGFR based on cysC (eGFRcysC) and Scr (eGFRScr). Among ambulatory patients with heart failure enrolled in PARADIGM-HF, we investigated the clinical significance of the difference between eGFRcysC and eGFRScr. More negative values (ie, eGFRScr>eGFRcysC) were associated with worse clinical outcomes (including mortality), poor quality of life, and frailty. In patients with progressive heart failure, which is characterized by muscle loss and poor nutritional status, the decline in kidney function was more pronounced when eGFR was estimated using cysC rather than Scr.

Diagnostic value and utility of commonly used biomarkers of cardiac and renal function in cardiorenal syndromes: a narrative review

Cardiorenal syndrome (CRS), first defined in 2004 as a consequence of the interactions between the kidneys and other circulatory departments leading to acute heart failure, has since been recognized as a complex clinical entity that is hard to define, diagnose and classify. The framework for the classification of CRS according to pathophysiologic background was laid out in 2008, dividing CRS into five distinct phenotypes. However, determining the timing of individual organ injuries and making a diagnosis of either renal or cardiac failure remains an elusive task. In clinical practice, the diagnosis and phenotyping of CRS is mostly based on using laboratory biomarkers in order to directly or indirectly estimate the degree of end-organ functional decline. Therefore, a well-educated clinician should be aware of the effects that the reduction of renal and cardiac function has on the diagnostic and predictive value and properties of the most commonly used biomarkers (e.g. troponins, N-terminal pro-brain natriuretic peptide, serum creatinine etc). They should also be acquainted, on a basic level, with emerging biomarkers that are specific to either the degree of glomerular integrity (cystatin C) or tubular injury (neutrophil gelatinase-associated lipocalin). This narrative review aims to provide a scoping overview of the different roles that biomarkers play in both the diagnosis of CRS and the prognosis of the disease in patients who have been diagnosed with it, along with highlighting the most important pitfalls in their interpretation in the context of impaired renal and/or cardiac function.

Cardiorenal Syndrome: A Literature Review

Cardiorenal syndrome (CRS) is a condition characterized by the intricate two-way relationship between the heart and kidneys, which can lead to acute or chronic dysfunction in these organs. The interplay between cardiorenal connectors and both hemodynamic and non-hemodynamic factors is crucial to understanding this syndrome. The clinical importance of these interactions is evident in the changes observed in hemodynamic factors, neurohormonal markers, and inflammatory processes. Identifying and understanding biomarkers associated with CRS is valuable for early detection and enabling intervention before significant organ dysfunction occurs. This comprehensive review focuses on the clinical significance of biomarkers in the diagnosis, prognosis, and management of CRS. Finally, it highlights the necessity for further advancements in managing this condition.

Long-Term Changes in Estimated Glomerular Filtration Rate in Left Ventricular Assist Device Recipients: A Longitudinal Joint Model Analysis

Background Advanced kidney disease is often a relative contraindication to left ventricular assist device (LVAD) implantation because of concerns for poor outcomes including worsening kidney disease. Data are lacking on long-term changes and sex-based differences in estimated glomerular filtration rate (eGFR), with published data limited by potential bias introduced by the competing risks of death and heart transplantation. Methods and Results We conducted a longitudinal analysis of 288 adults receiving durable continuous-flow LVADs from January 2010 to December 2017 at a single center. A joint model was constructed to evaluate change in eGFR over 2 years, the prespecified primary outcome, adjusted for the competing risks of death and heart transplantation. Median baseline eGFR was 60 mL/min per 1.73 m2 (interquartile range 42-78). At 2 years, 74 patients died and 104 received a heart transplant. In unadjusted analysis, LVAD recipients had a modest initial increase in eGFR of ≈2 mL/min per 1.73 m2 within the first 6 months after implantation, followed by a decrease in eGFR below baseline values at 1 and 2 years. Men experienced an eGFR decline of 5 to 10 mL/min per 1.73 m2 over the first year which then stabilized, while women had an ≈5 mL/min per 1.73 m2 increase in eGFR within the first 6 months followed by decline towards baseline eGFR levels (interaction P=0.005). Conclusions Estimated GFR remains relatively stable in most patients following LVAD implantation. Larger studies are needed to investigate sex-based differences in eGFR and to evaluate eGFR trajectory and mortality in LVAD recipients with lower eGFR.

Prediction, prevention, and management of right ventricular failure after left ventricular assist device implantation: A comprehensive review

Left ventricular assist devices (LVADs) are increasingly common across the heart failure population. Right ventricular failure (RVF) is a feared complication that can occur in the early post-operative phase or during the outpatient follow-up. Multiple tools are available to the clinician to carefully estimate the individual risk of developing RVF after LVAD implantation. This review will provide a comprehensive overview of available tools for RVF prognostication, including patient-specific and right ventricle (RV)-specific echocardiographic and hemodynamic parameters, to provide guidance in patient selection during LVAD candidacy. We also offer a multidisciplinary approach to the management of early RVF, including indications and management of right ventricular assist devices in this setting to provide tools that help managing the failing RV.

Renal Dysfunction in Patients with Left Ventricular Assist Device

Late-stage heart failure and renal dysfunction are often seen in conjunction. Cardiorenal syndrome (CRS) describes the complex interaction between the two disease states. Early literature described the pathophysiology of CRS as related only to reduced cardiac output and decreased renal perfusion. Recent literature suggests a more multifaceted mechanism. Left ventricular assist devices (LVAD), used as bridge-to-transplant and destination therapy in patients with heart failure, impact not only cardiac function but also renal function, especially in those patients with preoperative renal dysfunction. The mechanism by which LVAD implantation affects renal function is complex and understated in early literature. In this review, we discuss the pathogenesis of CRS, the impact of preoperative renal dysfunction in patients undergoing LVAD implantation, and the effect of LVAD implantation on postoperative renal function.

Muscle mass and estimates of renal function: a longitudinal cohort study

BACKGROUND

Creatinine is the most widely used test to estimate the glomerular filtration rate (GFR), but muscle mass as key determinant of creatinine next to renal function may confound such estimates. We explored effects of 24-h height-indexed creatinine excretion rate (CER index) on GFR estimated with creatinine (eGFR_Cr ), muscle mass-independent cystatin C (eGFR_Cys ), and the combination of creatinine and cystatin C (eGFR_Cr-Cys ) and predicted probabilities of discordant classification given age, sex, and CER index.

METHODS

We included 8076 adults enrolled in the PREVEND study. Discordant classification was defined as not having eGFR_Cr  <60 mL/min per 1.73 m² when eGFR_Cys was <60 mL/min/1.73 m² . Baseline effects of age and sex on CER index were quantified with linear models using generalized least squares. Baseline effects of CER index on eGFR were quantified with quantile regression and logistic regression. Effects of annual changes in CER index on trajectories of eGFR were quantified with linear mixed-effects models. Missing observations in covariates were multiply imputed.

RESULTS

Mean (SD) CER index was 8.0 (1.7) and 6.1 (1.3) mmol/24 h per meter in male and female participants, respectively (P_difference  < 0.001). In male participants, baseline CER index increased until 45 years of age followed by a gradual decrease, whereas a gradual decrease across the entire range of age was observed in female participants. For a 70-year-old male participant with low muscle mass (CER index of 2 mmol/24 h per meter), predicted baseline eGFR_Cr and eGFR_Cys disagreed by 24.7 mL/min/1.73 m² (and 30.1 mL/min/1.73 m² when creatinine was not corrected for race). Percentages (95% CI) of discordant classification in male and female participants aged 60 years and older with low muscle mass were 18.5% (14.8-22.1%) and 15.2% (11.4-18.5%), respectively. For a 70-year-old male participant who lost muscle during follow-up, eGFR_Cr and eGFR_Cys disagreed by 1.5, 5.0, 8.5, and 12.0 mL/min/1.73 m² (and 6.7, 10.7, 13.5, and 15.9 mL/min/1.73 m² when creatinine was not corrected for race) at baseline, 5 years, 10 years, and 15 years of follow-up, respectively.

CONCLUSIONS

Low muscle mass may cause considerable overestimation of single measurements of eGFR_Cr . Muscle wasting may cause spurious overestimation of repeatedly measured eGFR_Cr . Implementing muscle mass-independent markers for estimating renal function, like cystatin C as superior alternative to creatinine, is crucial to accurately assess renal function in settings of low muscle mass or muscle wasting. This would also eliminate the negative consequences of current race-based approaches.

The difference between cystatin C- and creatinine-based assessment of kidney function in acute heart failure

AIMS

Acute heart failure (HF) is associated with muscle mass loss, potentially leading to overestimation of kidney function using serum creatinine-based estimated glomerular filtration rate (eGFR_sCr ). Cystatin C-based eGFR (eGFR_CysC ) is less muscle mass dependent. Changes in the difference between eGFR_CysC and eGFR_sCr may reflect muscle mass loss. We investigated the difference between eGFR_CysC and eGFR_sCr and its association with clinical outcomes in acute HF patients.

METHODS AND RESULTS

A post hoc analysis was performed in 841 patients enrolled in three trials: Diuretic Optimization Strategy Evaluation (DOSE), Renal Optimization Strategies Evaluation (ROSE), and Cardiorenal Rescue Study in Acute Decompensated Heart Failure (CARRESS-HF). Intra-individual differences between eGFRs (eGFR_diff ) were calculated as eGFR_CysC -eGFR_sCr at serial time points during HF admission. We investigated associations of (i) change in eGFR_diff between baseline and day 3 or 4 with readmission-free survival up to day 60; (ii) index hospitalization length of stay (LOS) and readmission with eGFR_diff at day 60. eGFR_CysC reclassified 40% of samples to more advanced kidney dysfunction. Median eGFR_diff was -4 [-11 to 1.5] mL/min/1.73 m² at baseline, became more negative during admission and remained significantly different at day 60. The change in eGFR_diff between baseline and day 3 or 4 was associated with readmission-free survival (adjusted hazard ratio per standard deviation decrease in eGFR_diff : 1.14, P = 0.035). Longer index hospitalization LOS and readmission were associated with more negative eGFR_diff at day 60 (both P ≤ 0.026 in adjusted models).

CONCLUSIONS

In acute HF, a marked difference between eGFR_CysC and eGFR_sCr is present at baseline, becomes more pronounced during hospitalization, and is sustained at 60 day follow-up. The change in eGFR_diff during HF admission and eGFR_diff at day 60 are associated with clinical outcomes.

Biomarkers in Cardiorenal Syndrome

Cardiorenal syndrome is a clinical manifestation of the bidirectional interaction between the heart and kidney diseases. Over the last years, in patients with cardiovascular diseases, several biomarkers have been studied in order to better assess renal function as well as to identify patients prone to experiencing chronic or acute worsening of renal function. The aim of this review is to focus on the possible clinical usefulness of the most recent biomarkers in the setting of cardiorenal syndrome.

Levels of Trimethylamine N-Oxide Remain Elevated Long Term After Left Ventricular Assist Device and Heart Transplantation and Are Independent From Measures of Inflammation and Gut Dysbiosis

BACKGROUND

Trimethylamine N-oxide (TMAO)-a gut-derived metabolite-is elevated in heart failure (HF) and linked to poor prognosis. We investigated variations in TMAO in HF, left ventricular assist device (LVAD), and heart transplant (HT) and assessed its relation with inflammation, endotoxemia, oxidative stress, and gut dysbiosis.

METHODS

We enrolled 341 patients. TMAO, CRP (C-reactive protein), IL (interleukin)-6, TNF-α (tumor necrosis factor alpha), ET-1 (endothelin-1), adiponectin, lipopolysaccharide, soluble CD14, and isoprostane were measured in 611 blood samples in HF (New York Heart Association class I-IV) and at multiple time points post-LVAD and post-HT. Gut microbiota were assessed via 16S rRNA sequencing among 327 stool samples. Multivariable regression models were used to assess the relationship between TMAO and (1) New York Heart Association class; (2) pre- versus post-LVAD or post-HT; (3) biomarkers of inflammation, endotoxemia, oxidative stress, and microbial diversity.

RESULTS

ln-TMAO was lower among HF New York Heart Association class I (1.23 [95% CI, 0.52-1.94] µM) versus either class II, III, or IV (1.99 [95% CI, 1.68-2.30], 1.97 [95% CI, 1.71-2.24], and 2.09 [95% CI, 1.83-2.34] µM, respectively; all P<0.05). In comparison to class II-IV, ln-TMAO was lower 1 month post-LVAD (1.58 [95% CI, 1.32-1.83] µM) and 1 week and 1 month post-HT (0.97 [95% CI, 0.60-1.35] and 1.36 [95% CI, 1.01-1.70] µM). ln-TMAO levels in long-term LVAD (>6 months: 1.99 [95% CI, 1.76-2.22] µM) and HT (>6 months: 1.86 [95% CI, 1.66-2.05] µM) were not different from symptomatic HF. After multivariable adjustments, TMAO was not associated with biomarkers of inflammation, endotoxemia, oxidative stress, or microbial diversity.

CONCLUSIONS

TMAO levels are increased in symptomatic HF patients and remain elevated long term after LVAD and HT. TMAO levels were independent from measures of inflammation, endotoxemia, oxidative stress, and gut dysbiosis.

Renal Function in Patients with or without a Left Ventricular Assist Device Implant During Listing for a Heart Transplant

Background

Left ventricular assist device (LVAD) implantation may improve kidney function, but in patients awaiting heart transplantation, the long-term effects of LVAD implantation on renal function and subsequent clinical outcome are unclear.

Material/Methods

We analyzed data in patients with LVAD implants (n=139) and without LVAD implants (n=1038) who were listed for a heart transplant at our institution between 2000 and 2019. The primary endpoint was an impairment in renal function (decrease of creatinine-based estimated glomerular filtration rate [eGFR] by ≥30%) up to a maximum of 2 years after listing. Secondary endpoints were chronic kidney disease stage 4 or 5, heart transplantation, survival during listing, and 1-year survival after transplantation.

Results

Values for eGFR increased after LVAD implantation (P=0.001) and were higher at the time of waitlisting in the LVAD group than in the non-LVAD group (P=0.002), but were similar between groups at the end of waitlisting (P=0.75). Two-year freedom from renal impairment was 50.6% and 66.7% in the LVAD and non-LVAD groups, respectively, with a multivariable-adjusted hazard ratio for the LVAD versus the non-LVAD group of 1.78 (95% confidence interval 1.19–2.68; P=0.005). Two-year freedom from chronic kidney disease stages 4–5 was similar between study groups (LVAD group: 83.5%; non-LVAD group: 80.1%; =0.50). The 2-year probability of transplantation was slightly lower in the LVAD group than in the non-LVAD group (50.0% and 55.8%, respectively, P=0.017). However, 2-year survival on the waiting list and 1-year survival after transplantation did not differ significantly between study groups (P-values >0.20).

Conclusions

Our data indicate a transient improvement in creatinine-based eGFR values by LVAD implantation without influencing survival.