Trends in Left Ventricular Assist Device Implantation and Associated Mortality Among Patients With and Without ESRD

Kidney health and function with left ventricular assist devices

PURPOSE OF REVIEW

Mechanical circulatory support (MCS) is a group of evolving therapies used for indications ranging from temporary support during a cardiac procedure to permanent treatment of advanced heart failure. MCS is primarily used to support left ventricle function, in which case the devices are termed left ventricular assist devices (LVADs). Kidney dysfunction is common in patients requiring these devices, yet the impact of MCS itself on kidney health in many settings remains uncertain.

RECENT FINDINGS

Kidney dysfunction can manifest in many different forms in patients requiring MCS. It can be because of preexisting systemic disorders, acute illness, procedural complications, device complications, and long-term LVAD support. After durable LVAD implantation, most persons have improvement in kidney function; however, individuals can have markedly different kidney outcomes, and novel phenotypes of kidney outcomes have been identified.

SUMMARY

MCS is a rapidly evolving field. Kidney health and function before, during, and after MCS is relevant to outcomes from an epidemiologic perspective, yet the pathophysiology underlying this is uncertain. Improved understanding of the relationship between MCS use and kidney health is important to improving patient outcomes.

Distinctive kidney function trajectories following left ventricular assist device implantation

BACKGROUND

The aim of this study was to assess for distinct kidney function trajectories following left ventricular assist device (LVAD) placement. Cohort studies of LVAD recipients demonstrate that kidney function tends to increase early after LVAD placement, followed by decline and limited sustained improvement. Inter-individual differences in kidney function response may be obscured.

METHODS

We identified continuous flow LVAD implantations in US adults (2016-2017) from INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support). Primary outcomes were estimated glomerular filtration rate (eGFR) trajectories pre-implantation to ∼12 months. Latent class mixed models were applied to primary and validation samples. Clinical differences among trajectory groups were investigated.

RESULTS

Among 4,615 LVAD implantations, 5 eGFR trajectory groups were identified. The 2 largest groups (Groups 1 and 2) made up >80% of the cohort, and were similar to group average trajectories previously reported, with early eGFR rise followed by decline and stabilization. Three novel trajectory groups were found: worsening followed by sustained low kidney function (Group 3, 10.1%), sustained improvement (Group 4, 3.3%), and worsening followed by variation (Group 5, 1.7%). These groups differed in baseline characteristics and outcomes. Group 4 was younger and had more cardiogenic shock and pre-implantation dialysis; Group 3 had higher rates of pre-existing chronic kidney disease, along with older age.

CONCLUSIONS

Novel eGFR trajectories were identified in a national cohort, possibly representing distinct cardiorenal processes. Type 1 cardiorenal syndrome may have been predominant in Group 4, and parenchymal kidney disease may have been predominant in Group 3.

Outcomes With Left Ventricular Assist Device in End-Stage Renal Disease: A Systematic Review

Renal dysfunction is a common comorbidity in patients with advanced heart failure who may benefit from mechanical circulatory support (MCS). Unfortunately, renal function may result after left ventricular assist device (LVAD) implantation. The purpose of this study is to examine the outcomes of advanced heart failure patients with end-stage renal disease (ESRD) requiring mechanical circulatory support as a bridge to transplant (BTT) or destination therapy (DT). We searched Medline, Embase, and Cochrane in September 2021. The following keywords were used: left ventricular assist device or LVAD and end-stage renal disease or ESRD. Our study included case reports, case series, descriptive studies, and randomized control trials. Review articles, guidelines, systematic reviews, and meta-analyses were excluded. We also excluded pediatric cases. We identified 278 articles; 92 were duplicated, 186 articles entered the screening phase, and 133 articles were excluded by title and abstract. After the full-text screening, 40 articles were excluded. This systematic review included 13 articles. Among the contraindications to LVAD implantation, a general contraindication is for patients found to have stage 4 chronic kidney disease (CKD) (estimated glomerular filtration rate (eGFR): <30 mL/minute/1.73 m2), while those on dialysis are an absolute contraindication LVAD implantation. Despite the limited data and publications on LVADs in patients with ESRD, LVAD implantation as a bridge to transplantation or destination therapy may be considered in selected patients without increasing morbidity and mortality. Therefore, shared decision-making around the treatment of advanced heart failure with these patients and the care team is essential.

Sudden Cardiac Death in End-Stage Renal Disease

The challenge presented by sudden cardiac death in dialysis patients is to better define risk factors and delineate multiple etiologies. Only then can therapy be tailored to the highest risk patients and the incidence of sudden cardiac death be reduced. This article details the many possible etiologies and presents a brief overview of more recent research that may in the future prove of great benefit in improving the mortality of our patients with end-stage renal disease.

Acute Kidney Injury With Ventricular Assist Device Placement: National Estimates of Trends and Outcomes

RATIONALE & OBJECTIVE

Ventricular assist devices (VADs) are used for end-stage heart failure not amenable to medical therapy. Acute kidney injury (AKI) in this setting is common due to heart failure decompensation, surgical stress, and other factors. Little is known about national trends in AKI diagnosis and AKI requiring dialysis (AKI-D) and associated outcomes with VAD implantation. We investigated national estimates and trends for diagnosed AKI, AKI-D, and associated patient and resource utilization outcomes in hospitalizations in which implantable VADs were placed.

STUDY DESIGN

Cohort study of 20% stratified sample of US hospitalizations.

SETTING & PARTICIPANTS

Patients who underwent implantable VAD placement in 2006 to 2015.

EXPOSURE

No AKI diagnosis, AKI without dialysis, AKI-D.

OUTCOMES

In-hospital mortality, length of stay, estimated hospitalization costs.

ANALYTICAL APPROACH

Multivariate logistic and linear regression using survey design methods to account for stratification, clustering, and weighting.

RESULTS

An estimated 24,140 implantable VADs were placed, increasing from 853 in 2006 to 3,945 in 2015. AKI was diagnosed in 56.1% of hospitalizations and AKI-D occurred in 6.5%. AKI diagnosis increased from 44.0% in 2006 to 2007 to 61.7% in 2014 to 2015; AKI-D declined from 9.3% in 2006 to 2007 to 5.2% in 2014 to 2015. Mortality declined in all AKI categories but this varied by category: those with AKI-D had the smallest decline. Adjusted hospitalization costs were 19.1% higher in those with diagnosed AKI and 39.6% higher in those with AKI-D, compared to no AKI.

LIMITATIONS

Administrative data; timing of AKI with respect to VAD implantation cannot be determined; limited pre-existing chronic kidney disease ascertainment; discharge weights not derived for subpopulation of interest.

CONCLUSIONS

A decreasing proportion of patients undergoing VAD implantation experience AKI-D, but mortality among these patients remains high. AKI diagnosis with VAD implantation is increasing, possibly reflecting changes in AKI surveillance, awareness, and coding.

Impact of chronic kidney disease on in-hospital outcomes following left ventricular assist device placement: A national perspective

BACKGROUND

Left ventricular assist devices (LVADs) are being increasingly utilized for the treatment of stage-D heart failure. A LVAD is a battery-operated, mechanical pump that assists in pumping blood out of the left ventricle (LV) into the aorta, thereby lowering left ventricular burden. Prevalence of chronic kidney disease (CKD) is increasing in patients receiving LVAD.

OBJECTIVES

The purpose of this study was to compare in-hospital mortality and hospitalization expenditure associated with CKD in patients receiving LVAD implantation.

METHODS

Using the National Inpatient Sample from January 2012 through September 2015, index hospitalizations for LVAD were identified. Based on kidney function, LVAD recipients were divided into three groups: Group 1 included patients with normal renal function or CKD stages I-III. Groups 2 and 3 comprised of patients with CKD stage IV/V, and end-stage renal disease on dialysis respectively.

RESULTS

A total of 20,656 patients received LVAD during the study period. Mean age was 56.1 years; 76.8% were men. In a fully adjusted model, in-hospital mortality was higher in group 2 (OR: 1.33, CI: 1.16-1.50) and highest in group 3 (OR: 8.95, CI: 6.90-11.61). Similarly, the length of hospitalization, and hospitalization cost were higher in group 2 and highest in group 3.

CONCLUSION

Despite improving outcomes in patients receiving LVAD, CKD remained a significant health problem. Worsening in-hospital outcomes paralleling the degree of kidney dysfunction were observed in patients receiving LVADs in this study.