Deactivation of Left Ventricular Assist Devices at the End of Life: Narrative Review and Ethical Framework

Left ventricular assist devices (LVADs) have become an increasingly common advanced therapy in patients with severe symptomatic heart failure. Their unique nature in prolonging life through incorporation into the circulatory system raises ethical questions regarding patient identity and values, device ontology, and treatment categorization; approaching requests for LVAD deactivation requires consideration of these factors, among others. To that end, clinicians would benefit from a deeper understanding of: 1) the history and nature of LVADs; 2) the wider context of device deactivation and associated ethical considerations; and 3) an introductory framework incorporating best practices in requests for LVAD deactivation (specifically in controversial situations without obvious medical or device-related complications). In such decisions, heart failure teams can safeguard patient preferences without compromising ethical practice through more explicit advance care planning before LVAD implantation, early integration of hospice and palliative medicine specialists (maintained throughout the disease process), and further research interrogating behaviors and attitudes related to LVAD deactivation.

2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure" replaces the "2013 ACCF/AHA Guideline for the Management of Heart Failure" and the "2017 ACC/AHA/HFSA Focused Update of the 2013 ACCF/AHA Guideline for the Management of Heart Failure." The 2022 guideline is intended to provide patient-centric recommendations for clinicians to prevent, diagnose, and manage patients with heart failure.

METHODS

A comprehensive literature search was conducted from May 2020 to December 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from MEDLINE (PubMed), EMBASE, the Cochrane Collaboration, the Agency for Healthcare Research and Quality, and other relevant databases. Additional relevant clinical trials and research studies, published through September 2021, were also considered. This guideline was harmonized with other American Heart Association/American College of Cardiology guidelines published through December 2021. Structure: Heart failure remains a leading cause of morbidity and mortality globally. The 2022 heart failure guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with heart failure, with the intent to improve quality of care and align with patients' interests. Many recommendations from the earlier heart failure guidelines have been updated with new evidence, and new recommendations have been created when supported by published data. Value statements are provided for certain treatments with high-quality published economic analyses.

2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure

AIM

The "2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure" replaces the "2013 ACCF/AHA Guideline for the Management of Heart Failure" and the "2017 ACC/AHA/HFSA Focused Update of the 2013 ACCF/AHA Guideline for the Management of Heart Failure." The 2022 guideline is intended to provide patient-centric recommendations for clinicians to prevent, diagnose, and manage patients with heart failure.

METHODS

A comprehensive literature search was conducted from May 2020 to December 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from MEDLINE (PubMed), EMBASE, the Cochrane Collaboration, the Agency for Healthcare Research and Quality, and other relevant databases. Additional relevant clinical trials and research studies, published through September 2021, were also considered. This guideline was harmonized with other American Heart Association/American College of Cardiology guidelines published through December 2021.

STRUCTURE

Heart failure remains a leading cause of morbidity and mortality globally. The 2022 heart failure guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with heart failure, with the intent to improve quality of care and align with patients' interests. Many recommendations from the earlier heart failure guidelines have been updated with new evidence, and new recommendations have been created when supported by published data. Value statements are provided for certain treatments with high-quality published economic analyses.

2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure" replaces the "2013 ACCF/AHA Guideline for the Management of Heart Failure" and the "2017 ACC/AHA/HFSA Focused Update of the 2013 ACCF/AHA Guideline for the Management of Heart Failure." The 2022 guideline is intended to provide patient-centric recommendations for clinicians to prevent, diagnose, and manage patients with heart failure.

METHODS

A comprehensive literature search was conducted from May 2020 to December 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from MEDLINE (PubMed), EMBASE, the Cochrane Collaboration, the Agency for Healthcare Research and Quality, and other relevant databases. Additional relevant clinical trials and research studies, published through September 2021, were also considered. This guideline was harmonized with other American Heart Association/American College of Cardiology guidelines published through December 2021. Structure: Heart failure remains a leading cause of morbidity and mortality globally. The 2022 heart failure guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with heart failure, with the intent to improve quality of care and align with patients' interests. Many recommendations from the earlier heart failure guidelines have been updated with new evidence, and new recommendations have been created when supported by published data. Value statements are provided for certain treatments with high-quality published economic analyses.

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.

Myocardial perfusion reserve and global longitudinal strain as potential markers of coronary allograft vasculopathy in late-stage orthotopic heart transplantation

Coronary allograft vasculopathy (CAV) is a major cause of mortality in late-stage orthotopic heart transplantation (OHT) patients. Recent evidence has shown that myocardial perfusion reserve (MPR) derived from vasodilator cardiovascular magnetic resonance imaging (vCMR) and global longitudinal strain (GLS) from transthoracic echocardiography (TTE) are useful to detect CAV. However, previous studies have not comprehensively addressed whether these parameters are confounded by allograft rejection, myocardial scar/fibrosis, or allograft dysfunction. Our aim was to determine whether changes in late post-OHT MPR and GLS are due to CAV or other confounding factors. Twenty OHT patients (time from transplant to vCMR was 8.1 ± 4.1 years) and 30 controls (10 healthy volunteers and 20 with prior myocardial infarction to provide perspective with regards to the severity of any abnormalities seen in post-OHT patients) underwent vasodilator vCMR from which MPR index (MPRi), left ventricular ejection fraction (LVEF), and burden of late gadolinium enhancement (LGE) were quantified. TTE was used to measure GLS. The presence of CAV was determined from invasive coronary angiograms using thrombolysis in myocardial infarction (TIMI) frame counts and grading severity per guidelines. Previous endomyocardial biopsies were reviewed to assess association with episodes of rejection. We examined the correlations between MPRi and GLS with markers of CAV, allograft function, scar/fibrosis, and rejection. MPRi was abnormal in post-OHT patients compared to both healthy volunteers and MI controls. While there was no relationship between MPRi or GLS and LVEF, episodes of rejection, or LGE burden, both MPRi and GLS were associated with TIMI frame counts and presence and severity of CAV. Additionally, MPRi correlated with GLS (R = 0.68, P = 0.0002). In conclusion, MPRi and GLS are abnormal in late-stage OHT and associated with CAV, but not related to allograft rejection, myocardial scar/fibrosis, or allograft dysfunction. Non-invasive monitoring of MPRi and GLS may be a useful strategy to detect CAV.

Implantable Ventricular Assist Device Use and Outcomes in People With End-Stage Renal Disease

Background

People with end‐stage renal disease (ESRD) are at risk for advanced heart failure, but little is known about use and outcomes of durable mechanical circulatory support in this setting. We examined use and outcomes of implantable ventricular assist devices (VADs) in a national ESRD cohort.

Methods and Results

We performed a retrospective cohort study of Medicare beneficiaries with ESRD who underwent implantable VAD placement from 2006 to 2014. We examined in‐hospital and 1‐year mortality, all‐cause and cause‐specific hospitalizations, and heart/kidney transplantation outcomes. We investigated as predictors demographic factors, time‐period of VAD implantation, primary or post‐cardiotomy implantation, and duration of ESRD before VAD implantation. We identified 96 people with ESRD who underwent implantable VAD placement. At time of VAD implantation, 74 (77.1%) were receiving hemodialysis, 10 (10.4%) were receiving peritoneal dialysis and 12 (12.5%) had renal transplant. Time from incident ESRD to VAD implantation was median 4.0 (interquartile range 1.1, 8.2) years. Mortality during the implantation hospitalization was 40.6%. Within 1 year of implantation 61.5% of people had died. On multivariable analysis, males had half the mortality risk of females. Lower mortality risk was also seen with VAD implantation in a primary setting, and with more recent year of implantation, but these results did not reach statistical significance.

Conclusions

Medicare beneficiaries with ESRD are undergoing durable VAD implantation, often several years after incident ESRD, although in low numbers. Mortality is high among these patients, highlighting the need for investigations to improve treatment selection and management.

Routine C4d immunohistochemistry in cardiac allografts: Long-term outcomes

BACKGROUND

In the past decade, C4d has emerged as a potential marker for antibody-mediated rejection (AMR); however, evidence on its use as a prognostic tool has been controversial. Although the International Society for Heart and Lung Transplantation guideline recommends early routine surveillance of C4d in heart transplantation, there is no consensus on its value in the pathologic assessment of AMR. Herein we present a correlation analysis of C4d immunoreactivity in endomyocardial biopsies with clinical cardiac dysfunction, cellular rejection, human leukocyte antigen (HLA) status, cardiac allograft vasculopathy (CAV) and death.

METHODS

A total of 5,840 endomyocardial biopsies from 296 heart transplant recipients (January 2004 to December 2014) were stained prospectively for C4d. Strong, diffuse endothelial staining was considered positive. All patients had at least 1 year of follow-up. Positive C4d staining was present in 53 biopsies from 28 patients. Sixteen of 28 patients had clinically significant cardiac dysfunction at the time of positive biopsy. In C4d-positive patients, the mean panel-reactive antibody (PRA) level was 33%. Ten patients demonstrated a first C4d positivity within the first year post-transplant, whereas 18 patients had C4d positivity after 1 year post-transplant. At autopsy, all 11 C4d-positive patients examined demonstrated cardiac allograft vasculopathy (CAV) as the underlying cause of death. In contrast, only 2 of 8 (25%) C4d-negative patients had CAV at autopsy. In the surviving cohort, there was an angiographic diagnosis of higher-than-moderate CAV in 10 patients (3.8%).

RESULTS

C4d-positive patients contributed to 67% of the overall institutional mortality in heart transplant recipients. Late C4d positivity (>1 year post-transplant) demonstrated an even higher risk for developing CAV and poor prognosis than early C4d positivity (within 1 year). In the C4d-negative group with postmortem examination, 75% (6 of 8) deaths were due to non-cardiac causes.

CONCLUSIONS

Our findings show a positive association of C4d with CAV and death. We identified a prognostic role for C4d in heart transplantation warranting routine long-term detection of this marker in the pathologic evaluation of cardiac AMR.

Elevated Angiopoietin-2 Level in Patients With Continuous-Flow Left Ventricular Assist Devices Leads to Altered Angiogenesis and Is Associated With Higher Nonsurgical Bleeding

BACKGROUND

Nonsurgical bleeding is the most common adverse event in patients with continuous-flow left ventricular assist devices (LVADs) and is caused by arteriovenous malformations. We hypothesized that deregulation of an angiogenic factor, angiopoietin-2 (Ang-2), in patients with LVADs leads to increased angiogenesis and higher nonsurgical bleeding.

METHODS

Ang-2 and thrombin levels were measured by ELISA and Western blotting, respectively, in blood samples from 101 patients with heart failure, LVAD, or orthotopic heart transplantation. Ang-2 expression in endothelial biopsy was quantified by immunofluorescence. Angiogenesis was determined by in vitro tube formation from serum from each patient with or without Ang-2-blocking antibody. Ang-2 gene expression was measured by reverse transcription-polymerase chain reaction in endothelial cells incubated with plasma from each patient with or without the thrombin receptor blocker vorapaxar.

RESULTS

Compared with patients with heart failure or those with orthotopic heart transplantation, serum levels and endothelial expression of Ang-2 were higher in LVAD patients (P=0.001 and P<0.001, respectively). This corresponded to an increased angiogenic potential of serum from patients with LVADs (P<0.001), which was normalized with Ang-2 blockade. Furthermore, plasma from LVAD patients contained higher amounts of thrombin (P=0.003), which was associated with activation of the contact coagulation system. Plasma from LVAD patients induced more Ang-2 gene expression in endothelial cells (P<0.001), which was reduced with thrombin receptor blockade (P=0.013). LVAD patients with Ang-2 levels above the mean (12.32 ng/mL) had more nonsurgical bleeding events compared with patients with Ang-2 levels below the mean (P=0.003).

CONCLUSIONS

Our findings indicate that thrombin-induced Ang-2 expression in LVAD patients leads to increased angiogenesis in vitro and may be associated with higher nonsurgical bleeding events. Ang-2 therefore may contribute to arteriovenous malformation formation and subsequent bleeding in LVAD patients.

Successful percutaneous trans-catheter treatment of left ventricular assist device outflow graft stenosis with a covered stent

Case Report

Left ventricular assist devices improve survival in patients with advanced heart failure but can be associated with significant complication including infection, pump thrombosis, and de novo severe aortic insufficiency. Outflow graft stenosis is a much more rare complication, but one with significant hemodynamic consequences. Surgical repair is often necessary, but many patients are too high risk for further surgical intervention. We describe the first case of left ventricular assist device outflow graft stenosis treated with percutaneous trans‐catheter placement of a covered stent.

Reversal of impaired myocardial beta-adrenergic receptor signaling by continuous-flow left ventricular assist device support

BACKGROUND

Myocardial beta-adrenergic receptor (beta-AR) signaling is severely impaired in chronic heart failure (HF). This study was conducted to determine if left ventricular (LV) beta-AR signaling could be restored after continuous-flow LV assist device (LVAD) support.

METHODS

Twelve patients received LVADs as a bridge to transplant. Paired LV biopsy specimens were obtained at the time of LVAD implant (HF group) and transplant (LVAD group). The mean duration of LVAD support was 152 +/- 34 days. Myocardial beta-AR signaling was assessed by measuring adenylyl cyclase (AC) activity, total beta-AR density (B(max)), and G protein-coupled receptor kinase-2 (GRK2) expression and activity. LV specimens from 8 non-failing hearts (NF) were used as controls.

RESULTS

Basal and isoproterenol-stimulated AC activity was significantly lower in HF vs NF, indicative of beta-AR uncoupling. Continuous-flow LVAD support restored basal and isoproterenol-stimulated AC activity to levels similar to NF. B(max) was decreased in HF vs NF and increased to nearly normal in the LVAD group. GRK2 expression was increased 2.6-fold in HF vs NF and was similar to NF after LVAD support. GRK2 activity was 3.2-fold greater in HF vs NF and decreased to NF levels in the LVAD group.

CONCLUSIONS

Myocardial beta-AR signaling can be restored to nearly normal after continuous-flow LVAD support. This is similar to previous data for volume-displacement pulsatile LVADs. Decreased GRK2 activity is an important mechanism and indicates that normalization of the neurohormonal milieu associated with HF is similar between continuous-flow and pulsatile LVADs. This may have important implications for myocardial recovery.

Increased rejection rates in cardiac transplant associated with dexamethasone

BACKGROUND

Peri-operative immunosuppression in cardiac transplantation includes the use of intravenous methylprednisolone. During a national shortage, intravenous dexamethasone was substituted for methylprednisolone at standard equivalencies. Methylprednisolone and dexamethasone are used interchangeably in many clinical settings; however, their equivalency has not been demonstrated.

METHODS

Forty-two consecutive cardiac transplant patients were studied retrospectively. All patients received standard triple immunosuppression. Eighteen patients received dexamethasone and 24 methylprednisolone. Twelve patients were included for comparison after the methylprednisolone shortage resolved. Endomyocardial biopsy (EMB) results graded as > or =1B (ISHLT classification) were considered positive for acute cellular rejection.

RESULTS

More patients who received dexamethasone as induction had cellular rejection (12/17; (70%) vs. 14/33; (42%); p=0.05). Four patients were excluded because of deaths unrelated to cardiac function. The increased rate of rejection seen during dexamethasone substitution declined after reinstitution of methylprednisolone (p=0.05).

CONCLUSIONS

Peri-operative high-dose dexamethasone in cardiac transplants was associated with higher rates of acute cellular rejection. The equivalencies of dexamethasone and methylprednisolone differ from accepted standards when used in pulse doses. Peri-operative use of glucocorticoids may rely on mechanisms that are different from those considered in the standard equivalency measures. Pulse doses of dexamethasone and methylprednisolone in transplantation may not be interchangeable at standard equivalencies.

Advance directives in the cardiac care unit

BACKGROUND

Despite effective therapies, mortality for many cardiovascular diseases remains higher than for many cancers and is difficult to predict. Guidelines recommend discussing advance directives (AD), including living wills and durable powers of attorney, with heart failure patients. The Patient Self-Determination Act mandates such discussions with all hospitalized patients. Little data are available on AD prevalence in patients with serious cardiac disease.

METHODS

Patients admitted to a cardiac care unit (CCU) were surveyed regarding demographics, medical history, prevalence of AD, and interest in obtaining more information about AD. Histories of life-threatening cardiac diagnoses were tabulated. Prevalence of AD and interest in obtaining more information about AD were obtained via chart review from patients on an oncology (ONC) floor at the same hospital.

RESULTS

One hundred twelve CCU (average age 58 +/- 16 years, 47 women) and 105 ONC (average age 58 +/- 14 years, 32 women) patients were enrolled. Prevalence of AD was not different between CCU and ONC patients (26% vs 31%, P = .37). Among CCU patients with prior hospitalizations but no AD, 21 of 64 did not recall being asked about AD. Cardiac care unit patients with heart failure and pulmonary hypertension were more likely to report being asked about AD in the past (39 of 54, P = .03 and 7 of 9, P = .008, respectively), but only heart failure patients were more likely to want more information about AD (P = .005). Of patients without AD, 83% from CCU and 18% from ONC wanted more information on AD (P < .001).

CONCLUSIONS

Prevalence of AD in the CCU was low, and many patients did not recall prior AD discussions. The CCU patients without AD were more likely to want information about AD than the ONC patients. A renewed emphasis on AD discussions with cardiovascular patients is needed and would be welcomed. Advance directives should be emphasized in cardiovascular training programs.

Nesiritide as Bridge to Multi-Organ Transplantation: A Case Report

Nesiritide, an intravenous form of human B-type natriuretic peptide, has been approved as treatment for patients with acute decompensated heart failure. Due to its action on different receptors, nesiritide has many effects, including vasodilation and natriuresis. Cardiac preload and afterload decrease, leading to an increase in cardiac output through effects on smooth muscle and the kidneys. As a bridge to cardiac transplantation, nesiritide has been used to maintain vasodilation and diuresis without sacrificing kidney function. Our patient, prior to multi-organ transplantation, had a pulmonary capillary wedge pressure of 41 mm Hg on milrinone monotherapy, which decreased slightly with nitroprusside and further decreased to 4 mm Hg after the addition of nesiritide. The patient's measured creatinine clearance level was calculated to be 40 mL/min. When nesiritide therapy was begun, the renal function did not improve, but, as the hemodynamics improved, renal function did not decrease.

Automated border detection on contrast enhanced echocardiographic images

BACKGROUND

Accurate determination of left ventricular ejection fraction (LV EF) is of paramount importance in the evaluation of patients with cardiovascular disease. Quantitative techniques for the automated calculation of EF exist however, the robustness of these techniques is dependent on adequate endocardial border definition and therefore are difficult to use in patients with limited images. We sought to combine the endocardial border enhancing effects of contrast echocardiography with an automated border detection technique to provide quantitative and accurate determination of LV EF.

METHODS

Thirty-nine consecutive patients referred to nuclear cardiology for EF determination underwent radionuclide angiography followed by echocardiographic imaging using prototype software that allowed automated border detection during contrast infusion.

RESULTS

Adequate LV cavity opacification with contrast was possible in 38/39 patients. The mean radionuclide EF was 50+/-16% (range 19-73). There was no statistically significant difference between the mean nuclear EF and averaged echocardiographically determined EF (51+/-18%). The mean bias was 0.6 with limits of agreement that were +15 and -14.

CONCLUSION

This study demonstrated that prototype software successfully tracked the contrast enhanced endocardial border allowing accurate calculation of LV EF.