Advances in Treatment of Cardiac Amyloid

Healthcare and economic burden of heart failure with amyloidosis: An insight from National Readmission Database

INTRODUCTION

We analyzed trends, causes and predictors of 30-days readmission in cardiac amyloidosis and inspected the impact of these readmissions on mortality, morbidity, and utilization of healthcare resources.

METHODS

Heart Failure with cardiac amyloidosis patients were selected from National readmission Database (NRD) using ICD-10 CM codes. Patients younger than 18 years, elective readmissions, readmissions due to trauma, patients with missing data and December 2018 admissions were excluded. Primary outcome was all-cause 30-day readmissions rate, secondary outcomes were factors associated with 30-days readmissions and their effect on morbidity, mortality, and healthcare resource utilization.

RESULTS

Out of 4123 total heart failure with cardiac amyloidosis index admissions in 2018, 3374 patients were included in final analysis. 19.6% were readmitted within 30 days. Readmitted patients were younger, sicker, admitted to small or large hospital. Hypertensive heart and Chronic Kidney Disease (CKD Stage I-IV) with Congestive Heart Failure (CHF), hypertensive heart and CKD (Stage V) or End Stage Renal Disease (ESRD) with CHF, hypertensive heart disease with CHF, acute kidney failure, and sepsis were the most common causes of readmissions. Young age, admission to small and large size hospitals were independent predictors of 30-day readmissions. Readmissions had higher mortality, costed 6.6 extra in hospital days to patients and $16380 per admission to healthcare system.

CONCLUSIONS

Cardiac amyloidosis readmissions were associated with increased morbidity and mortality of patients and extra burden on the healthcare system. There is a need to identify patients at risk for readmissions to improve patient outcomes and decrease healthcare cost.

Clinical implications of atrial natriuretic peptide amyloidosis

A 74-year-old woman with a history of diastolic heart failure and refractory atrial fibrillation (AF) presented with unstable angina for coronary artery bypass grafting. Routine pathological analysis of tissue specimens obtained from the left atrial appendage revealed subendocardial and interstitial fibrosis and patchy amyloid deposits with Congo red staining demonstrating filamentous deposits. Mass spectrometry was consistent with isolated atrial amyloidosis (IAA). IAA in this patient was found incidentally on routine postoperative pathology, but likely contributed to significant morbidity. The established relationship between IAA with AF and diastolic heart failure underscores the relevance. Further delineating the pathogenesis has potentially immense implications for the future management of associated conditions. To bridge the gaps in the understanding, a standardised approach to diagnosis is needed to open the door to a large-scale study and further work toward establishing evidence-based management pathways.

Amyloidosis and 30-Day Outcomes Among Patients With Heart Failure: A Nationwide Readmissions Database Study

BACKGROUND

The burden of amyloidosis among hospitalized patients is increasing over time. However, amyloidosis remains an underdiagnosed cause of heart failure (HF) hospitalization among older adults.

OBJECTIVES

We investigated the prevalence and prognostic implications of amyloidosis among patients hospitalized with HF.

METHODS

All hospitalizations for primary diagnosis of HF between January 1, 2010, and August 31, 2015, identified in the Nationwide Readmissions Database were categorized into those with and without a secondary diagnosis of amyloidosis. HF hospitalizations with amyloidosis were then matched in a 3:1 fashion to HF hospitalizations without amyloidosis using the year of admission, discharge quarter, age, sex, and Charlson comorbidity index. Primary outcomes were inpatient mortality and 30-day readmission. Multivariable logistic regression was used to estimate the association between HF with amyloidosis and clinical outcomes.

RESULTS

Of 1,593,360 HF hospitalizations that met inclusion criteria, 2,846 (0.18%) had HF with a secondary diagnosis of amyloidosis and were matched to 8,515 hospitalizations for HF without amyloidosis. Hospitalizations for HF with amyloidosis were associated with higher prevalence of kidney disease (56% vs. 45%), malignancy (20% vs. 4%), and higher inpatient mortality (6% vs. 3%) as compared with HF without amyloidosis. In adjusted analyses, HF with amyloidosis was associated with higher odds of in-hospital mortality (odds ratio: 1.46; 95% confidence interval [CI]: 1.17 to 1.82), 30-day readmission (odds ratio: 1.17; 95% CI: 1.05 to 1.31), and longer mean length of stay (least-squares mean difference: 1.46; 95% CI: 1.12 to 1.80).

CONCLUSIONS

In patients hospitalized with decompensated HF, presence of amyloidosis was associated with higher risk of inpatient mortality and 30-day readmission.

Transthyretin Cardiac Amyloidosis and Aortic Stenosis: Connection and Therapeutic Implications

Background

There is a growing interest in the observed significant incidence of transthyretin cardiac amyloidosis in elderly patients with aortic stenosis. Approximately, 16% of patients with severe aortic stenosis undergoing aortic valve replacement have transthyretin cardiac amyloidosis. Outcomes after aortic valve replacement appear to be worst in patients with concomitant transthyretin cardiac amyloidosis.

Methods

Publications in PubMed, Cochrane Library, and Embase databases were systematically searched from January 2012 to September 2018 using the keywords transthyretin, amyloidosis, and aortic stenosis. All studies published in English that reported the prevalence, association and outcomes of transthyretin cardiac amyloidosis in patients with aortic stenosis undergoing were included.

Results/Conclusion

The relationship between aortic stenosis and transthyretin cardiac amyloidosis is not well understood. A few studies have proven successful surgical management when both conditions coexist. This systematic review suggests that transthyretin cardiac amyloidosis is common in elderly patients with aortic stenosis and tend to have high mortality rates after AVR. The significant incidence of the two diseases occurring simultaneously warrants further investigation to improve management strategies in the future.

Prognostic Value of Right Ventricular Dysfunction in Patients With AL Amyloidosis: Comparison of Different Techniques by Cardiac Magnetic Resonance

BACKGROUND

Right ventricular (RV) dysfunction is common in patients with amyloid light-chain (AL) amyloidosis. While cardiac MRI is the reference standard tool for RV assessment, there are a number of measures of RV function that can be evaluated and it is yet unknown which of these results in the highest prognostic performance in AL amyloidosis.

PURPOSE

To examine the prognostic value of various measures of RV function in a bid to find which best predicts outcome in AL amyloidosis.

STUDY TYPE

Single-center, prospective.

SUBJECTS

In all, 129 patients (mean age, 58 ± 11 years; 61.2% men) with biopsy-proven AL amyloidosis.

FIELD STRENGTH/SEQUENCE

3.0T / balanced steady-state free-precession cine.

ASSESSMENT

RV ejection fraction (EF), RV fractional area change (FAC), RV long axis strain (LAS), RV free wall longitudinal strain (FWS), RV global longitudinal strain (GLS), and tricuspid annular plane systolic excursion (TAPSE).

STATISTICAL TESTS

Mann-Whitney U-tests, Student's t-tests, receiver-operating characteristic curves, Kaplan-Meier curves, Cox proportional hazards regression models, and C-statistics.

RESULTS

During the median follow-up period of 38.0 months (interquartile range, 18.5-58.0 months), all-cause mortality occurred in 95 patients (73.6%). The RVEF, RVGLS, TAPSE, RVFAC, and RVFWS were significant predictors of outcome in univariate Cox regression (all P < 0.001). After adjusting for New York Heart Association (NYHA) class, Mayo staging 2004, left ventricular (LV) EF, and LV mass index, RVFWS (HR [hazard ratio] =1.074; 95% CI [confidence interval]: 1.041-1.108; P < 0.001) was an independent predictor of all-cause mortality and had a higher C-statistic (0.753) compared to the model including RVEF (C-statistic = 0.724, P = 0.034), the model including RVFAC (C-statistic = 0.723, P = 0.033), and the model including RVGLS (C-statistic =0.733, P = 0.011).

DATA CONCLUSION

RV dysfunction appears to be an independent determinant of outcome in patients with AL amyloidosis. RVFWS is a better predictor of all-cause mortality than RVEF, RVFAC, or RVGLS.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY STAGE: 5.

Implications of Heparan Sulfate and Heparanase in Amyloid Diseases

Amyloidosis refers to a group of diseases characterized by abnormal deposition of denatured endogenous proteins, termed amyloid, in the affected organs. Analysis of biopsy and autopsy tissues from patients revealed the presence of heparan sulfate proteoglycans (HSPGs) along with amyloid proteins in the deposits. For a long time, HSPGs were believed to occur in the deposits as an innocent bystander. Yet, the consistent presence of HSPGs in various deposits, regardless of the amyloid species, led to the hypothesis that these macromolecular glycoconjugates might play functional roles in the pathological process of amyloidosis. In vitro studies have revealed that HSPGs, or more precisely, the heparan sulfate (HS) side chains interact with amyloid peptides, thus promoting amyloid fibrillization. Although information on the mechanisms of HS participation in amyloid deposition is limited, recent studies involving a transgenic mouse model of Alzheimer's disease point to an active role of HS in amyloid formation. Heparanase cleavage alters the molecular structure of HS, and thus modulates the functional roles of HS in homeostasis, as well as in diseases, including amyloidosis. The heparanase transgenic mice have provided models for unveiling the effects of heparanase, through cleavage of HS, in various amyloidosis conditions.

A histopathologic schema to quantify the burden of cardiac amyloidosis: Relationship with survival and echocardiographic parameters

BACKGROUND

Despite routine use of echocardiographic parameters to evaluate the severity of cardiac amyloidosis (CA), this methodology has not been well validated. We developed a histopathologic schema for quantifying CA burden and evaluated its relationship with clinical outcomes. Additionally, echocardiographic parameters were tested as potential noninvasive indices of CA burden.

METHODS

We retrospectively studied 59 patients with CA (17 light chain, 42 transthyretin) who underwent endomyocardial biopsies. Light microscopy with staining was used to categorize CA burden as mild-to-moderate (<50%) or high (≥50%). Kaplan-Meier survival analysis was performed for the two groups. In 34 patients with good-quality echocardiograms, we measured left ventricular volumes, ejection fraction (EF), interventricular septal thickness (IVSt), posterior wall thickness (PWt), LV mass, lateral e'-velocity, and global longitudinal strain (GLS). These parameters were compared between the two groups.

RESULTS

Thirty-five patients had mild-to-moderate and 24 severe amyloid burden. Kaplan-Meier curves demonstrated a trend toward worse mortality with high CA burden, which was more common and associated with higher mortality specifically in transthyretin-type patients. Echocardiography-derived IVSt, PWt, and LV mass were directly related to CA burden, while LV EF, e'-velocity, and GLS magnitude were inversely related to CA burden.

CONCLUSIONS

Our findings provided a signal that CA burden is a clinically important entity with potentially valuable prognostic information. Echocardiographic parameters of LV anatomy and function correlate with histopathologic burden of CA, which is inversely related to survival. Further studies are needed to determine whether these parameters could be used as imaging biomarkers of treatment-related changes in CA burden.