Pressure-volume relationships in patients with transthyretin (ATTR) cardiac amyloidosis secondary to V122I mutations and wild-type transthyretin: Transthyretin Cardiac Amyloid Study (TRACS)

Mechanisms of damage and therapies for cardiac amyloidosis: a role for inflammation?

The term cardiac amyloidosis (CA) refers to the accumulation of extracellular amyloid deposits in the heart because of different conditions often affecting multiple organs including brain, kidney and liver. Notably, cardiac involvement significantly impacts prognosis of amyloidosis, with cardiac biomarkers playing a pivotal role in prognostic stratification. Therapeutic management poses a challenge due to limited response to conventional heart failure therapies, necessitating targeted approaches aimed at preventing, halting or reversing amyloid deposition. Mechanisms underlying organ damage in CA are multifactorial, involving proteotoxicity, oxidative stress, and mechanical interference. While the role of inflammation in CA remains incompletely understood, emerging evidence suggests its potential contribution to disease progression as well as its utility as a therapeutic target. This review reports on the cardiac involvement in systemic amyloidosis, its prognostic role and how to assess it. Current and emerging therapies will be critically discussed underscoring the need for further efforts aiming at elucidating CA pathophysiology. The emerging evidence suggesting the contribution of inflammation to disease progression and its prognostic role will also be reviewed possibly offering insights into novel therapeutic avenues for CA.

Effect of beta-blockade on mortality in patients with cardiac amyloidosis: A systematic review and meta-analysis

AIMS

The efficacy of beta-blockers in cardiac amyloidosis (CA) is unclear, and concerns persist that neurohormonal blockade could worsen symptoms of heart failure. We aimed to assess whether beta-blocker therapy is associated with improved survival in patients with CA.

METHODS AND RESULTS

We conducted a systematic review and meta-analysis to examine the impact of beta-blocker therapy on mortality in patients with CA. A search of MEDLINE and EMBASE was performed in August 2023. Data were extracted from observational studies and synthesized with pooling and random effects meta-analysis. Thirteen studies including 4215 patients with CA were incorporated in this review (3688 transthyretin amyloid cardiomyopathy (ATTR-CM), 502 light chain amyloid cardiomyopathy (AL-CM), 25 not specified; age 74.8 ± 5.5 years, 76% male). Over half of the cohort (52%) received beta-blockers and the rate of beta-blocker withdrawal was 28%. All-cause mortality was 33% (range: 13-51%) after a median follow-up ranging from 13 to 36 months. There was an inverse association between the pooled risk of mortality and the use of beta-blocker therapy at any time point (RR 0.48, 95% CI 0.29-0.80, I2 = 83%, P = 0.005, seven studies). There was no association between mortality and beta-blocker use (RR 0.65, 95% CI 0.29-1.47, I2 = 88%, P = 0.30) in the three studies that only included patients with ATTR-CM. The three studies that included patients with both ATTR-CM and AL demonstrated an association of beta-blocker use with reduced mortality (OR 0.43, 95% CI 0.29-0.63, I2 = 4%, P < 0.001). The only study that solely included 53 patients with AL-CM, demonstrated improved survival among the 53% who were able to tolerate beta-blocker therapy (RR 0.26, 95% CI 0.08-0.79, P = 0.02). The absence of information on staging of CA is an important limitation of this study.

CONCLUSIONS

Treatment with beta-blockers may be associated with a survival benefit in patients with CA, but these findings are subject to selection and survivor biases. Definitive prospective randomized trials of conventional heart failure therapies are needed in CA.

Pathophysiology of Cardiac Amyloidosis

Amyloidosis refers to a heterogeneous group of disorders sharing common pathophysiological mechanisms characterized by the extracellular accumulation of fibrillar deposits consisting of the aggregation of misfolded proteins. Cardiac amyloidosis (CA), usually caused by deposition of misfolded transthyretin or immunoglobulin light chains, is an increasingly recognized cause of heart failure burdened by a poor prognosis. CA manifests with a restrictive cardiomyopathy which progressively leads to biventricular thickening, diastolic and then systolic dysfunction, arrhythmias, and valvular disease. The pathophysiology of CA is multifactorial and includes increased oxidative stress, mitochondrial damage, apoptosis, impaired metabolism, and modifications of intracellular calcium balance.

Standard Therapy in Cardiac Amyloidosis: What is Known, What is "Gray"

Amyloidosis is a systemic disease due to the accumulation of misfolded amyloid fibrils that damage the heart and worsen the prognosis. Heart failure (HF), a condition frequently linked with an advanced stage of this disease, is the most prevalent clinical manifestation that leads to its diagnosis. However, due to the growing awareness of the occurrence of cardiac amyloidosis (CA), it is now possible to perform an early diagnosis and have a positive impact on its natural course. This study aims to highlight the most compelling issues concerning patients' clinical management with HF and CA.

2024 Australia-New Zealand Expert Consensus Statement on Cardiac Amyloidosis

Over the past 5 years, early diagnosis of and new treatments for cardiac amyloidosis (CA) have emerged that hold promise for early intervention. These include non-invasive diagnostic tests and disease modifying therapies. Recently, CA has been one of the first types of cardiomyopathy to be treated with gene editing techniques. Although these therapies are not yet widely available to patients in Australia and New Zealand, this may change in the near future. Given the rapid pace with which this field is evolving, it is important to view these advances within the Australian and New Zealand context. This Consensus Statement aims to update the Australian and New Zealand general physician and cardiologist with regards to the diagnosis, investigations, and management of CA.

Exploring Transthyretin Amyloid Cardiomyopathy: A Comprehensive Review of the Disease and Upcoming Treatments

Transthyretin amyloid cardiomyopathy (ATTR-CM) is a mutation-based genetic disorder due to the accumulation of unstable transthyretin protein and presents with symptoms of congestive heart failure (CHF) and numerous extracardiac symptoms like carpal tunnel syndrome and neuropathy. Two subtypes of ATTR-CM are hereditary and wild-type, both of which have different risk factors, gender prevalence and major clinical symptoms. Timely usage of imaging modalities like echocardiography, cardiac magnetic imaging resonance, and cardiac scintigraphy has made it possible to suspect ATTR-CM in patients presenting with CHF. Management of ATTR-CM includes appropriate treatment for heart failure for symptomatic relief, prevention of arrhythmias and heart transplantation for nonresponders. With the recent approval of tafamidis in the successful management of ATTR-CM, numerous potential therapeutic points have been identified to stop or delay the progression of ATTR-CM. This article aims to provide a comprehensive review of ATTR-CM and insights into its novel therapeutics and upcoming treatments.

Advances in the diagnosis and treatment of transthyretin amyloid cardiomyopathy

Transthyretin amyloid cardiomyopathy (ATTR-CM) is an underrecognized cause of heart failure (HF). ATTR-CM can lead to a number of cardiovascular manifestations including HF, rhythm disturbances, and valvular disease that ultimately limit quality of life and prognosis. Due to advances in diagnostic modalities and therapeutic options, the prevalence of ATTR-CM is rising. There are several classes of medications under active investigation, though most therapies are most efficacious if instituted early on in the disease course. As such, early clinical recognition and prompt diagnosis are crucial to improving disease related outcomes. In this review, we highlight clinical manifestations of ATTR-CM as well as contemporary diagnostic and treatment approaches to the disease.

Hemodynamic testing to guide vasodilator therapy in cardiac amyloidosis

Cardiac amyloidosis is a restrictive cardiomyopathy for which diuretics are frequently used, but vasodilators have classically been relatively contraindicated due to side effects of hypotension. In the setting of decompensated heart failure, this may not be the case. We report a man with advanced cardiac amyloidosis who presented to the hospital with decompensated heart failure, in part, due to elevated systemic vascular resistance. Through the use of invasive hemodynamic testing, we were able to demonstrate an increase in cardiac output in response to a nitroprusside challenge. In turn, the patient had an improvement in his symptoms and was sent home on afterload reducing medications. This discerns a subpopulation of cardiac amyloidosis patients in decompensated heart failure who benefit from medications that reduce systemic vascular resistance, and can benefit from hemodynamic testing, especially when diuretics fail to control symptoms.

Learning objective

Medications that cause peripheral vasodilation are standard therapy for patients with reduced ejection fraction, however, they are seldom used for patients with cardiac amyloidosis due to adverse effects. In some cases, there may be value in using hemodynamic measurements in patients with advanced cardiac amyloidosis to guide management as some patients may have hemodynamics that resemble those of systolic heart failure. This may offer a novel approach to symptomatic treatment of advanced cardiac amyloidosis.

Effect of patisiran on stroke volume in hereditary transthyretin-mediated amyloidosis: insights from pressure-volume analysis of the APOLLO study

AIMS

Transthyretin-mediated (ATTR) amyloidosis is caused by deposition of transthyretin protein fibrils in the heart, nerves, and other organs. Patisiran, an RNA interference therapeutic that inhibits hepatic synthesis of transthyretin, was approved for the treatment of hereditary ATTR amyloidosis with polyneuropathy based on the phase 3 APOLLO study. We use left ventricular (LV) stroke volume (SV) to quantify LV function overtime and non-invasive pressure-volume techniques to delineate the effects of patisiran on LV mechanics in the pre-specified cardiac subpopulation of the APOLLO study.

METHODS AND RESULTS

Left ventricular SV was assessed by transthoracic echocardiography at baseline, and after 9 and 18 months of therapy. To determine the mechanisms underlying changes in LV SV, non-invasive pressure-volume parameters, including the end-systolic and end-diastolic pressure-volume relationship, were derived using single beat techniques. At baseline, the mean SV was 51 ± 14 ml. At 9 months, the least-squares mean change in SV was -0.3 ± 1.2 ml for patisiran and -5.4 ± 1.9 ml for placebo (p = 0.021). At 18 months, the least-squares mean change in SV was -1.7 ± 1.3 ml for patisiran and - 8.1 ± 2.3 ml for placebo (p = 0.016). Decline in LV SV was driven by diminished LV capacitance in placebo relative to patisiran.

CONCLUSIONS

Patisiran may delay progression of LV chamber dysfunction starting at 9 months of therapy. These data elucidate the mechanisms by which transthyretin-reducing therapies modulate progression of cardiac disease and need to be confirmed in ongoing phase 3 trials.

Epidemiology, Mechanisms, and Management of Atrial Fibrillation in Cardiac Amyloidosis

Cardiac amyloidosis (CA) is a restrictive disease that results from intramyocardial amyloid deposition due to immunoglobulin light chain or transthyretin proteins. Up to two-third of CA patients have atrial fibrillation (AF) due to electromechanical, autonomic, and hemodynamic disturbances. AF in CA carries particularly increased risk of thromboembolism, prompting anticoagulation therapy irrespective of CHA₂DS₂VASc score. However, CA is also associated with enhanced bleeding risk that warrants thorough assessment of bleeding profile before initiation of anticoagulation. Management of AF in CA is challenging because these patients poorly tolerate rate control agents, while cardiomyopathy precludes most antiarrhythmic agents, leaving amiodarone as the preferred antiarrhythmic drug. The effectiveness of direct current cardioversion in restoring sinus rhythm in CA is comparable with that in the general population, although intraprocedural complication rates could be higher. Transesophageal echocardiogram should be performed prior to direct current cardioversion, given high incidence of intracardiac thrombus in these patients. Finally, the data on catheter ablation is limited.

Prognostic value of cardiopulmonary exercise testing in patients with transthyretin cardiac amyloidosis

The aim of this study is to evaluate the prognostic value of cardiopulmonary testing (CPET) in a cohort of patients with transthyretin cardiac amyloidosis (ATTR-CA). ATTR-CA is associated with a progressive reduction in functional capacity. The prognostic role of CPET parameters and in particular of normalized peak VO2 (%ppVO2) remains to be thoroughly evaluated. In this study, 75 patients with ATTR-CA underwent cardiological evaluation and CPET in a National Referral Center for cardiac amyloidosis (Careggi University Hospital, Florence). Fifty-seven patients (76%) had wild-type ATTR. Median age was 80 (75-83) years, 68 patients (91%) were men. Peak oxygen consumption (14.1 ± 4.1 ml/kg/min) and %ppVO₂ (68.4 ± 18.8%) were blunted. Twenty-seven (36%) patients had an abnormal pressure response to exercise. After a median follow-up of 25 (12-31) months, the composite outcome of death or heart failure hospitalization was registered in 19 (25.3%) patients. At univariate analysis %ppVO₂ was a stronger predictor for the composite outcome than peak VO₂. %ppVO₂ and NT-proBNP remained associated with the composite outcome at multivariate analysis. The optimal predictive threshold for %ppVO₂ was 62% (sensitivity: 71%; specificity: 68%; AUC: 0.77, CI 0.65-0.88). Patients with %ppVO₂ ≤ 62%and NT-proBNP > 3000 pg had a worse prognosis with 1- and 2-year survival of 69 ± 9% and 50 ± 10%, respectively. CPET is a safe and useful prognostic tool in patients with ATTR-CA. CPET may help to identify patients with advanced disease that may benefit from targeted therapy.

Stroke volume and myocardial contraction fraction in transthyretin amyloidosis cardiomyopathy: A systematic review

Background

Cardiac amyloidosis (CA) is primarily a restrictive cardiomyopathy in which the impairment of diastolic function is dominant. Despite this, the left ventricular ejection fraction (LVEF) may be depressed in the late stage of the disease, but it poorly predicts prognosis in the earlier phases and does not represent well the pathophysiology of CA. Many echocardiographic parameters resulted important diagnostic and prognostic tools in patients with CA. Stroke volume (SV) and myocardial contraction fraction (MCF) may be obtained both with echocardiography and cardiac magnetic resonance (MRI). They reflect many factors intrinsically related to the pathophysiology of CA and are therefore potentially associated with symptoms and prognosis in CA.

Objectives

To collect and summarize the current evidence on SV and MCF and their clinical and prognostic role in transthyretin (TTR-CA).

Methods and results

We performed a systematic review following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. We searched the literature database for studies focusing on SV and MCF in patients with TTR-CA. We analysed the following databases: PUBMED, Cochrane Library, EMBASE, and Web of Science database. Fourteen studies were included in the review. Both SV and MCF have important prognostic implications and are related to mortality. Furthermore, SV is more related to symptoms than LVEF and predicts tolerability of beta-blocker therapy in TTR-CA. Finally, SV showed to be an excellent measure to suggest the presence of TTR-CA in patients with severe aortic stenosis.

Conclusion

Stroke volume and MCF are very informative parameters that should be routinely assessed during the standard echocardiographic examination of all patients with TTR-CA. They carry a prognostic role while being associated with patients' symptoms.

Systematic review registration

https://doi.org/10.17605/OSF.IO/ME7DS.

The Emerging Role of Sodium-glucose Cotransporter 2 Inhibitors in Heart Failure

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are a relatively novel drug class that most cardiologists are becoming familiar with. By contrasting glucose reabsorption in the proximal convoluted tubule of the nephron, SGLT2 inhibition results in glycosuria with improved glycemic control. Although originally introduced as anti-diabetic medications, the cardiovascular effects of SGLT2i have progressively emerged, leading them to become one of the four pillars for the treatment of heart failure with reduced ejection fraction (HFrEF) according to the 2021 guidelines from the European Society of Cardiology. Also, two recent randomized trials have demonstrated SGLT2i as the first compounds with proven prognostic impact in heart failure with preserved ejection fraction (HFpEF), setting a milestone in the treatment for this condition. While the exact pathogenic mechanisms mediating the substantial reduction in cardiovascular death and heart failure (HF) hospitalizations are still controversial, there is growing clinical evidence on the efficacy and safety of SGLT2i in various subsets of patients with HF. As known, heart failure is a complex and heterogeneous clinical syndrome with a magnitude of phenotypes and a variety of underlying hemodynamic and physiological aspects which cannot be fully incorporated into the traditional left ventricular ejection fraction based classification adopted in clinical trials. The aim of this review is to provide an overview of the cardiovascular benefits and indications of SGLT2i across different HF patterns and to highlight current gaps in knowledge that should be addressed by future research.

Racial Differences in Val122Ile-Associated Transthyretin Cardiac Amyloidosis

BACKGROUND

The valine-to-isoleucine substitution (Val122Ile) is the most common variant of transthyretin (TTR) amyloidosis in the United States, affecting primarily individuals of African descent. This variant has been identified recently in a cluster of white individuals in Italy.

METHODS AND RESULTS

Clinical phenotype and chamber performance of Black and white individuals with Val122Ile TTR cardiac amyloidosis (ATTR-CA) were compared. Compared to white patients (n = 17), Black individuals (n = 53) had lower systolic blood pressures (110 vs 131 mmHg, <0.001), reduced pulse pressures (41 vs 58 mmHg; P < 0.001), and impaired renal function (eGFR 46 vs 67 mL/min/1.73m²; P < 0.001) at presentation. Systolic properties and arterial elastance were similar. Black patients had end-diastolic pressure-volume relationships that were shifted upward and leftward relative to those of white patients, indicating reduced left ventricular chamber capacitance. Pressure-volume area at a left ventricular end-diastolic pressure of 30 mmHg was lower in Black than in white individuals (8055 mmHg/mL vs 11,538 mmHg/mL; P = 0.008).

CONCLUSION

Despite presenting at ages similar to those of white patients, Black individuals with Val122Ile-associated ATTR-CA had a greater degree of cardiac chamber dysfunction at the time of diagnosis due to impaired ventricular capacitance. Whether these differences are attributable to amyloidosis or other cardiovascular disease requires further study.

Management of Cardiac Symptoms in Amyloidosis

Cardiac amyloidosis (CA) results in symptoms of heart failure, atrial and ventricular arrhythmias, conduction disturbances, and profound autonomic dysfunction. These symptoms present unique management challenges as compared with patients without CA, and can be very debilitating. Thus, management of the cardiovascular symptoms of these patients plays a central role in their care. This review presents an overview of the typical cardiovascular manifestations encountered in patients with CA and highlights the key management considerations for each.

Ventricular arrhythmia burden and implantable Cardioverter-defibrillator outcomes in transthyretin cardiac amyloidosis

BACKGROUND

As targeted treatments for amyloid transthyretin cardiomyopathy (ATTR-CM) are becoming available, we aim to characterize the rates of ventricular arrhythmias (VAs), implantable cardioverter-defibrillator (ICD) utilization, and their impact on survival.

METHODS

This is a retrospective cohort study of 130 patients with ATTR-CM diagnosed at Emory University's Cardiac Amyloidosis Center between April 2012 and September 2020. VAs were defined as non-sustained or sustained ventricular tachycardia and ventricular fibrillation.

RESULTS

Of 130 patients, 42 had wild-type disease (wtATTR) and 88 had hereditary variants (hATTR), most commonly Val122Ile (89%). At ATTR-CM diagnosis, 80 (62%) patients had EF ≤ 40% consistent with systolic heart failure. Of the 69 (53%) patients with documented VAs significantly higher rates occurred among those with EF ≤ 40% compared with EF > 40% (67% vs 28%, p = 0.001). Thirty-two patients (25 hATTR, 7 wtATTR) had primary prevention ICDs implanted. Eight (25%) of these patients received appropriate ICD therapy while two (6%) experienced inappropriate therapy. Comparing patients with EF ≤ 35% with and without ICDs did not reveal any survival difference (3.3 ± 0.5 vs. 2.8 ± 0.4 years, p = 0.699).

CONCLUSIONS

High rates of VAs and appropriate ICD therapy were found amongst a unique cohort of largely hereditary ATTR-CM patients with a high rate of systolic heart failure. This article is protected by copyright. All rights reserved.

2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure: Developed by the Task Force for the diagnosis and treatment of acute and chronic heart failure of the European Society of Cardiology (ESC). With the special contribution of the Heart Failure Association (HFA) of the ESC

Document Reviewers: Rudolf A. de Boer (CPG Review Coordinator) (Netherlands), P. Christian Schulze (CPG Review Coordinator) (Germany), Magdy Abdelhamid (Egypt), Victor Aboyans (France), Stamatis Adamopoulos (Greece), Stefan D. Anker (Germany), Elena Arbelo (Spain), Riccardo Asteggiano (Italy), Johann Bauersachs (Germany), Antoni Bayes-Genis (Spain), Michael A. Borger (Germany), Werner Budts (Belgium), Maja Cikes (Croatia), Kevin Damman (Netherlands), Victoria Delgado (Netherlands), Paul Dendale (Belgium), Polychronis Dilaveris (Greece), Heinz Drexel (Austria), Justin Ezekowitz (Canada), Volkmar Falk (Germany), Laurent Fauchier (France), Gerasimos Filippatos (Greece), Alan Fraser (United Kingdom), Norbert Frey (Germany), Chris P. Gale (United Kingdom), Finn Gustafsson (Denmark), Julie Harris (United Kingdom), Bernard Iung (France), Stefan Janssens (Belgium), Mariell Jessup (United States of America), Aleksandra Konradi (Russia), Dipak Kotecha (United Kingdom), Ekaterini Lambrinou (Cyprus), Patrizio Lancellotti (Belgium), Ulf Landmesser (Germany), Christophe Leclercq (France), Basil S. Lewis (Israel), Francisco Leyva (United Kingdom), AleVs Linhart (Czech Republic), Maja-Lisa Løchen (Norway), Lars H. Lund (Sweden), Donna Mancini (United States of America), Josep Masip (Spain), Davor Milicic (Croatia), Christian Mueller (Switzerland), Holger Nef (Germany), Jens-Cosedis Nielsen (Denmark), Lis Neubeck (United Kingdom), Michel Noutsias (Germany), Steffen E. Petersen (United Kingdom), Anna Sonia Petronio (Italy), Piotr Ponikowski (Poland), Eva Prescott (Denmark), Amina Rakisheva (Kazakhstan), Dimitrios J. Richter (Greece), Evgeny Schlyakhto (Russia), Petar Seferovic (Serbia), Michele Senni (Italy), Marta Sitges (Spain), Miguel Sousa-Uva (Portugal), Carlo G. Tocchetti (Italy), Rhian M. Touyz (United Kingdom), Carsten Tschoepe (Germany), Johannes Waltenberger (Germany/Switzerland) All experts involved in the development of these guidelines have submitted declarations of interest. These have been compiled in a report and published in a supplementary document simultaneously to the guidelines. The report is also available on the ESC website www.escardio.org/guidelines For the Supplementary Data which include background information and detailed discussion of the data that have provided the basis for the guidelines see European Heart Journal online.

Feasibility of the contraction-relaxation coupling index in outcome prediction for patients with acute heart failure

AIMS

Contemporary heart failure (HF) classification based on left ventricular (LV) ejection fraction is limited for comprehensive assessment of LV function. We aimed to validate the feasibility of the contraction-relaxation coupling index (CRC) as a novel predictor for clinical outcomes in patients with acute HF.

METHODS AND RESULTS

A total of 3266 consecutive patients (median age: 74 years, 53% male) with acute HF were included. CRC was defined as the ratio of end-diastolic elastance (LV end-diastolic pressure/stroke volume) to end-systolic elastance (LV end-systolic pressure/end-systolic volume). The risk for 1 year composite endpoint of all-cause mortality or hospitalization for HF (primary outcome) was compared after group categorization using CRC tertiles (Tertile 1: CRC ≤ 0.17, Tertile 2: 0.17 < CRC ≤ 0.40, and Tertile 3: 0.40 < CRC). The median CRC was 0.3 and the median LVEF was 42%. After adjustment for clinical and echocardiographic covariates, CRC was an independent predictor for the primary outcome (hazard ratio [HR]: 1.74, 95% confidence interval [CI]: 1.47-2.07 in Tertile 3 and HR: 1.21, 95% CI: 1.02-1.44 in Tertile 2 when compared with Tertile 1; HR: 1.23, 95% CI: 1.14-1.33 per one-standard deviation increment in CRC). The risk model with CRC showed better performance in outcome discrimination than the model with LVEF (c-statistic 0.701 vs. 0.699, P for difference <0.001). Patients with higher CRC demonstrated better effectiveness of neurohormonal blockade for the primary outcome compared with those with lower CRC (HR: 0.38, 95% CI: 0.29-0.50 in Tertile 3 and HR: 0.67, 95% CI: 0.52-0.89 in Tertile 1).

CONCLUSIONS

CRC provides an independent value for outcome prediction in patients with acute HF. CRC would be a sensitive indicator for prognostic risk stratification and for predicting treatment response to the neurohormonal blockade.

Lack of Association Between Neurohormonal Blockade and Survival in Transthyretin Cardiac Amyloidosis

Background

Despite the belief that heart failure therapies are not effective in transthyretin cardiac amyloidosis, data are limited. We tested the association of neurohormonal blockade use with survival.

Methods and Results

A total of 309 consecutive patients with transthyretin cardiac amyloidosis were identified. Medication inventory was obtained at baseline and subsequent visits. Exposure included a neurohormonal blockade class (β‐blocker [βB], angiotensin‐converting enzyme inhibitor/angiotensin receptor blocker, and mineralocorticoid antagonist) at baseline and subsequent visits. βB was modeled as baseline use, time‐varying use, and in an inverse probability treatment weighted model. Primary outcome was all‐cause mortality analyzed with adjusted Cox proportional hazards models. Continuing compared with stopping βB during follow‐up was tested. Mean age was 73.2 years, 84.1% were men, and 17.2% had atrial fibrillation/flutter at baseline. At the time of study entry, 49.8% were on βBs, 35.0% were on angiotensin‐converting enzyme inhibitors/angiotensin receptor blockers, and 23.9% were on mineralocorticoid antagonists. For the total cohort, there was a trend toward harm in the unadjusted model for baseline βB use, but this was neutral after adjustment. When βB use was analyzed as a time‐varying exposure, there was no association with mortality. βB discontinuation was associated with decreased mortality for the total cohort. Findings were consistent in inverse probability treatment weighted models. For angiotensin‐converting enzyme inhibitor/angiotensin receptor blocker or mineralocorticoid antagonist use, there was no association with mortality after adjustment for the total cohort.

Conclusions

There was no association of neurohormonal blockade use with survival in transthyretin cardiac amyloidosis. For the total cohort, deprescribing βB may be associated with improved survival. Additional studies are needed to confirm these findings.

ATTR Amyloidosis: Current and Emerging Management Strategies: JACC: CardioOncology State-of-the-Art Review

Transthyretin cardiac amyloidosis (ATTR-CA) is increasingly diagnosed owing to the emergence of noninvasive imaging and improved awareness. Clinical penetrance of pathogenic alleles is not complete and therefore there is a large cohort of asymptomatic transthyretin variant carriers. Screening strategies, monitoring, and treatment of subclinical ATTR-CA requires further study. Perhaps the most important translational triumph has been the development of effective therapies that have emerged from a biological understanding of ATTR-CA pathophysiology. These include recently proven strategies of transthyretin protein stabilization and silencing of transthyretin production. Data on neurohormonal blockade in ATTR-CA are limited, with the primary focus of medical therapy on judicious fluid management. Atrial fibrillation is common and requires anticoagulation owing to the propensity for thrombus formation. Although conduction disease and ventricular arrhythmias frequently occur, little is known regarding optimal management. Finally, aortic stenosis and ATTR-CA frequently coexist, and transcatheter valve replacement is the preferred treatment approach.

Management Strategies for Atrial Fibrillation and Flutter in Patients with Transthyretin Cardiac Amyloidosis

Atrial fibrillation (AF) and flutter (AFL) frequently complicate transthyretin cardiac amyloidosis (ATTR-CM). Management poses challenges as rate control drugs are poorly tolerated and data addressing tolerability and efficacy of rhythm control is limited. We report outcomes of AF/AFL in ATTR-CM in a single center observational study of patients seen at our Amyloidosis Center with wild-type or hereditary ATTR-CM diagnosed between 2005-2019 including 84 patients (average age 74 ± 10 years, 94% male) with 27.6 ± 22.8 months follow-up. AF/AFL occurred in 61 patients (73%). Rapid ventricular response was common as was attempted rate control. However, discontinuation of rate control drugs was frequent (80%), often for adverse effects. Rhythm control was attempted in 64%, usually with cardioversion (DCCV) or ablation. Post-DCCV recurrence was common (91%) and time to recurrence was similar with or without anti-arrhythmic drugs (5.8 months (IQR 1.9-12.5) vs 6.2 months (IQR 1.9-12.5) p = 0.83). Ablation was performed in 23% with AFL (all for typical AFL) with 14% recurrence after mean of 60.9 months. Ablation for AF was performed in 12% with 86% recurrence after median of 6.2 months (IQR 5.6-12.3). Most patients (62%) with rhythm control had subjective improvement (≥1 NYHA class or resolved palpitations). In conclusion, AF/AFL was common in our cohort. Rate control was poorly tolerated and often abandoned. Rhythm control led to symptomatic improvement in a majority of cases, but durable success was limited. DCCV was modestly successful and not significantly improved with anti-arrhythmics. Ablation was successful with typical AFL but had limited success in AF.

Wild-Type Transthyretin Amyloidosis in Female Patients - Consideration of Sex Differences

Background: With recent advances in non-invasive diagnostic tools, some studies indicate that wild-type transthyretin amyloidosis (ATTRwt) may be more common in females than previously reported. However, the clinical characteristics of female ATTRwt patients have not been determined.

Methods and Results: Of the 78 consecutive patients with ATTRwt in our cohort, 14 (17.9 %) were female. Compared with male patients, female ATTRwt patients had smaller left ventricular (LV) wall thicknesses (ventricular septum thickness 12.9 vs. 14.2 mm [P=0.081]; posterior wall thickness 12.7 vs. 13.6 mm [P=0.035]) and a higher LV ejection fraction (EF; mean [±SD] 58.4±8.9% vs. 48.9±11.8%; P=0.006). However, the severity of heart failure (HF), as assessed by HF stage, New York Heart Association functional class and B-type natriuretic peptide concentrations, did not differ between female and male patients. Moreover, LV mass index and relative wall thickness were increased and the stroke volume index was reduced in both female and male patients. In organ biopsies, female patients had a higher sensitivity to transthyretin deposition from abdominal fat than male patients (positive abdominal fat biopsy 80.0 % vs. 26.5%; P=0.016).

Conclusions: This study suggests that a relatively large proportion of elderly females have ATTRwt. Female ATTRwt patients had HF symptoms even at the stage of mild LV hypertrophy and preserved EF. Abdominal fat biopsy may be useful to diagnose ATTRwt, especially in female patients with HF.

Prognostic Role of Cardiopulmonary Exercise Testing in Wild-Type Transthyretin Amyloid Cardiomyopathy Patients Treated With Tafamidis

BACKGROUND

The prognostic value of cardiopulmonary exercise testing (CPET) in patients with wild-type transthyretin cardiac amyloidosis treated with tafamidis is unknown.

METHODS AND RESULTS

This retrospective study included patients with wtATTR who underwent baseline cardiopulmonary exercise testing and were treated with tafamidis from August 31, 2018, until March 31, 2020. Univariate logistic and multivariate cox-regression models were used to predict the occurrence of the primary outcome (composite of mortality, heart transplant, and palliative inotrope initiation). A total of 33 patients were included (median age 82 years, interquartile range [IQR] 79-84 years), 84% were Caucasians and 79% were males). Majority of patients had New York Heart Association functional class III disease at baseline (67%). The baseline median peak oxygen consumption (VO₂) and peak circulatory power (CP) were 11.35 mL/kg/min (IQR 8.5-14.2 mL/kg/min) and 1485.8 mm Hg/mL/min (IQR 988-2184 mm Hg/mL/min), respectively, the median ventilatory efficiency was 35.7 (IQR 31-41.2). After 1 year of follow-up, 11 patients experienced a primary end point. Upon multivariate analysis, the low peak VO₂ (hazard ratio [HR] 0.43, 95% confidence interval [CI] 0.23-0.79, P = .007], peak CP (HR 0.98, 95% CI 0.98-0.99, P = .02), peak oxygen pulse (HR 0.62, 95% CI 0.39-0.97, P = .03), and exercise duration of less than 5.5 minutes (HR 5.82, 95% CI 1.29-26.2, P = .02) were significantly associated with the primary outcome.

CONCLUSIONS

Tafamidis-treated patients with wtATTR who had baseline low peak VO₂, peak CP, peak O₂ pulse, and exercise duration of less than 5.5 minutes had worse outcomes.

Trajectory of left ventricular geometry and diastolic dysfunction in hereditary transthyretin cardiac amyloidosis

Amyloid transthyretin (ATTR) depositions cause left ventricular (LV) hypertrophy, diastolic dysfunction, and heart failure. The time course of changes in LV geometry and diastolic dysfunction has not been fully reported in patients with ATTR cardiomyopathy. A 79‐year‐old woman with previous myocardial infraction presented with shortness of breath on exertion, and progressive bilateral lower extremity weakness and polyneuropathy. She was diagnosed with Val30Met hereditary ATTR cardiomyopathy by cardiac biopsy and genetic testing. During the past 5 year period, significant LV concentric remodelling with small LV cavity occurred, resulting in an increased LV stiffness and prolonged LV relaxation. This case report highlights the time course of changes in LV geometry and diastolic function and the importance of early diagnosis of ATTR cardiomyopathy.

Pathophysiology and Therapeutic Approaches to Cardiac Amyloidosis

Often considered a rare disease, cardiac amyloidosis is increasingly recognized by practicing clinicians. The increased rate of diagnosis is in part due the aging of the population and increasing incidence and prevalence of cardiac amyloidosis with advancing age, as well as the advent of noninvasive methods using nuclear scintigraphy to diagnose transthyretin cardiac amyloidosis due to either variant or wild type transthyretin without a biopsy. Perhaps the most important driver of the increased awareness is the elucidation of the biologic mechanisms underlying the pathogenesis of cardiac amyloidosis which have led to the development of several effective therapies with differing mechanisms of actions. In this review, the mechanisms underlying the pathogenesis of cardiac amyloidosis due to light chain (AL) or transthyretin (ATTR) amyloidosis are delineated as well as the rapidly evolving therapeutic landscape that has emerged from a better pathophysiologic understanding of disease development.

Narrative review of pharmacotherapy for transthyretin cardiac amyloid

Treatment of cardiac amyloidosis is determined by the amyloid type and degree of involvement. Two types of amyloid commonly infiltrate the heart: immunoglobulin light-chain amyloid (AL), and transthyretin amyloid (ATTR), that encompasses other two forms, a hereditary form (hATTR), and a sporadic, age-related wild-type (wtATTR). The prevalence is expected to increase with aging population. The natural history of ATTR cardiomyopathy includes progressive heart failure (HF), complicated by arrhythmias and conduction system disease. New therapies options have been approved or are under investigation. We performed a narrative literature review, manually-searched the reference lists of included articles and relevant reviews. Treatment for cardiac ATTR should be directed towards alleviation of HF symptoms and to slow or stop progressive amyloid deposition. Conventional HF medications are poorly tolerated and may not alter the disease progression or symptoms, except perhaps with the administration of diuretics. There are three approaches of therapy for ATTR cardiomyopathy: tetramer stabilizers, inhibition of ATTR protein synthesis and clearance of deposited fibrils. Tafamidis diminishes the progression of cardiomyopathy, functional parameters, improves overall outcome in patients with early disease stages, irrespective of ATTR status and is well tolerated. Diflunisal has shown promising results in early studies, but at the expense of significant side effects. Two new agents, antisense oligonucleotides, patisiran and inotersen are under investigation in cardiac amyloidosis. Patisiran appears to be the most effective treatment for hATTR, although evidence is limited, with a relatively small cardiac subpopulation. Therapies considering clearance of amyloid fibrils from tissue remain experimental. In conclusion, tafamidis is the only approved agent for the treatment of ATTR cardiomyopathy although multiple other agents have shown promising early results and are undergoing clinical trials. Careful consideration of the type of ATTR, comorbidities and disease stage will be key in deciding the optimal therapy for ATTR patients.

Topoisomerase 2B Decrease Results in Diastolic Dysfunction via p53 and Akt: A Novel Pathway

Diastolic dysfunction is condition of a stiff ventricle and a function of aging. It causes significant cardiovascular mortality and morbidity, and in fact, three million Americans are currently suffering from this condition. To date, all the pharmacological clinical trials have been negative. The lack of success in attenuating/ameliorating diastolic dysfunction stems from lack of duplication of myriads of clinical manifestation in pre-clinical settings. Here we report, a novel genetically engineered mice which may represents a preclinical model of human diastolic dysfunction to some extent. Topoisomerase 2 beta (Top2b) is an important enzyme in transcriptional activation of some inducible genes through transient double-stranded DNA breakage events around promoter regions. We created a conditional, tissue-specific, inducible Top2b knockout mice in the heart. Serendipitously, echocardiographic parameters and more invasive analysis of left ventricular function with pressure–volume loops show features of diastolic dysfunction. This was also confirmed histologically. At the cellular level, the Top2b knockdown showed morphological changes and molecular signaling akin to human diastolic dysfunction. Reverse phase protein analysis showed activation of p53 and inhibition of, Akt, as the possible mediators of diastolic dysfunction. Finally, activation of p53 and inhibition of Akt were confirmed in myocardial biopsy samples obtained from human diastolic dysfunctional hearts. Thus, we report for the first time, a Top2b downregulated preclinical mice model for diastolic dysfunction which demonstrates that Akt and p53 are the possible mediators of the pathology, hence representing novel and viable targets for future therapeutic interventions in diastolic dysfunction.

Sex Differences in the Phenotype of Transthyretin Cardiac Amyloidosis Due to Val122Ile Mutation: Insights from Noninvasive Pressure-Volume Analysis

BACKGROUND

Transthyretin cardiac amyloidosis (ATTR-CA) is an under-recognized cause of heart failure with preserved ejection fraction. In the United States, the valine-to-isoleucine substitution (Val122Ile) is the most common inherited variant. Data on sex differences in presentation and outcomes of Val122Ile associated ATTR-CA are lacking.

METHODS AND RESULTS

In a retrospective, single-center study of 73 patients diagnosed with Val122Ile associated ATTR-CA between 2001 and 2018, sex differences in clinical and echocardiographic data at the time of diagnosis were evaluated. Pressure-volume analysis using noninvasive single beat techniques was used to compare chamber performance. Compared with men (n = 46), women (n = 27) were significantly older at diagnosis, 76 years vs 69 years; P < .001. The end-systolic pressure-volume relationship, 5.1 mm Hg*m²/mL vs 4.3 mm Hg*m²/mL; P = .27, arterial elastance, 5.5 mm Hg*m²/mL vs 5.7 mm Hg*m²/mL; P = .62, and left ventricular capacitance were similar between sexes as was pressure-volume areas indexed to a left ventricular end-diastolic pressure of 30 mm Hg, a measure of overall pump function. The 3-year mortality rates were also similar, 34% vs 43%; P = .64.

CONCLUSIONS

Despite being significantly older at time of diagnosis with Val122Ile associated ATTR-CA, women have similar overall cardiac chamber function and rates of mortality to men, suggesting a less aggressive disease trajectory. These findings should be confirmed with longitudinal studies.

Primary prevention implantable cardioverter-defibrillators in transthyretin cardiac amyloidosis

BACKGROUND

Due to the poor long-term prognosis of patients with transthyretin cardiac amyloidosis (ATTR-CA), the role of primary prevention implantable cardioverter-defibrillators (ICDs) in this patient population remains controversial. We aimed to study the impact of primary prevention ICDs on survival in patients with ATTR-CA.

METHODS

Among 382 patients diagnosed with ATTR-CA at our institution between 2004 and 2018, 19 had primary prevention ICDs implanted. This cohort was matched in a 1:3 manner on the basis of age, gender, ejection fraction (EF) and ATTR-CA stage with 57 patients without cardiac devices. Patients were followed up for a mean of 23 ± 19 months. Our primary outcome of interest was all-cause mortality.

RESULTS

Mean EF at the time of ICD implantation was 28 ± 8%. No patients had a history of sustained ventricular arrhythmia (VA) at the time of implant. Only a minority of patients were tolerant of optimal medical therapy due to renal impairment, hypotension, or a combination of the two. Death occurred in 43 (75%) patients without primary prevention ICDs and 16 (84%) patients with primary prevention ICDs, P = .26. Of the 19 patients with ICDs, three had inappropriate shocks delivered for atrial fibrillation, and none had therapies for sustained VAs. On Cox proportional hazards analyses, the presence of a primary prevention ICD was not associated with improved survival (HR 0.72, 95% CI 0.4-1.3, P = .27).

CONCLUSION

Primary prevention ICDs do not prolong survival in patients with ATTR-CA and a reduced EF. Our findings are observational and will need to be validated in future prospective studies.

Multimodality Imaging in the Evaluation and Management of Cardiac Amyloidosis

Systemic amyloidosis is a heterogeneous group of disorders where misfolded proteins deposit in the various organs as nonbranching fibrils with a β-pleated-sheet structure called amyloid. Extensive extracellular deposition of these amyloid fibrils eventually leads to organ dysfunction. Involvement of the heart, termed as cardiac amyloidosis, leads to heart failure if left untreated and carries high morbidity and mortality. Current interest in cardiac amyloidosis is growing rapidly thanks to the recent development of effective targeted treatment options, driving the need for better and earlier detection of the condition, which is largely underdiagnosed and far commoner than recognized. Timely diagnosis of cardiac amyloidosis is challenging, but is poised to improve with emergence of newer noninvasive imaging techniques, potentially obviating the need for endomyocardial biopsy in some patients and providing prognostic information. With recent advances in the therapeutic options for cardiac amyloidosis, an area of immense interest is the adoption of imaging as biomarkers for longitudinal assessment of disease progression and treatment response. In this article, we provide an overview of cardiac amyloidosis, discuss the role of imaging modalities in cardiac amyloidosis, and explore future directions for imaging in cardiac amyloidosis.

Analysis of Cardiac Amyloidosis Progression Using Model-Based Markers

Deposition of amyloid in the heart can lead to cardiac dilation and impair its pumping ability. This ultimately leads to heart failure with worsening symptoms of breathlessness and fatigue due to the progressive loss of elasticity of the myocardium. Biomarkers linked to the clinical deterioration can be crucial in developing effective treatments. However, to date the progression of cardiac amyloidosis is poorly characterized. There is an urgent need to identify key predictors for disease progression and cardiac tissue function. In this proof of concept study, we estimate a group of new markers based on mathematical models of the left ventricle derived from routine clinical magnetic resonance imaging and follow-up scans from the National Amyloidosis Center at the Royal Free in London. Using mechanical modeling and statistical classification, we show that it is possible to predict disease progression. Our predictions agree with clinical assessments in a double-blind test in six out of the seven sample cases studied. Importantly, we find that multiple factors need to be used in the classification, which includes mechanical, geometrical and shape features. No single marker can yield reliable prediction given the complexity of the growth and remodeling process of diseased hearts undergoing high-dimensional shape changes. Our approach is promising in terms of clinical translation but the results presented should be interpreted with caution due to the small sample size.

Amyloid Cardiomyopathy

Amyloid cardiomyopathy is emerging as an important and under-recognised cause of heart failure and cardiac arrhythmias, especially in older adults. This disorder is characterised by extracellular deposition of amyloid fibrils that form due to misfolding of secreted light chains (AL) or transthyretin protein (ATTR). In ATTR, amyloid aggregates typically result from excessive accumulation of wild-type transthyretin (ATTRwt) or from protein structural defects caused by TTR gene variants (ATTRv). Amyloid fibril deposition may predominantly affect the heart or show multi-system involvement. Previously considered to be rare and inexorably progressive with no specific therapy, there has been enormous recent interest in ATTR cardiomyopathy due to upwardly-revised estimates of disease prevalence together with development of disease-modifying interventions. Because of this, there is a clinical imperative to have a high index of suspicion to identify potential cases and to be aware of contemporary diagnostic methods and treatment options. Genetic testing should be offered to all patients with proven ATTR to access the benefits of new therapies specific to ATTRv and allow predictive testing of family members. With heightened awareness of amyloid cardiomyopathy and expanded use of genetic testing, a substantial rise in the numbers of asymptomatic individuals who are carriers of pathogenic variants is expected, and optimal strategies for monitoring and treatment of these individuals at risk need to be determined. Pre-emptive administration of fibril-modifying therapies provides an unprecedented opportunity for disease prevention and promises to change amyloid cardiomyopathy from being a fatal to a treatable disorder.

The quintessential form of diastolic heart failure in older adults: Wild type transthyretin cardiac amyloidosis

Wild-type transthyretin cardiac amyloidosis (ATTRwt) is now recognized as a common cause of heart failure with preserved ejection fraction (HFpEF). In this review, we aim to describe the unique epidemiologic, pathophysiologic, and clinical features associated with ATTwt cardiac amyloidosis. Compared to other etiologies of HFpEF, ATTRwt cardiac amyloidosis affects almost exclusively older adults, demonstrating a characteristic age-dependent penetrance that impacts both the diagnosis and treatment of the disease. In addition, ATTR cardiac amyloidosis demonstrates a unique pathophysiology in contrast to other etiologies of HFpEF, which results in a characteristic phenotype that can raise suspicion for ATTRwt cardiac amyloid in the appropriate demographic. With these distinguishing features in mind, we aim to describe the specific signs, symptoms, and imaging characteristics associated with ATTRwt cardiac amyloidosis, including the role of nuclear scintigraphy that has essentially eliminated the need for biopsy in most patients with suspected disease. Finally, we review the evidence behind the available therapeutic agents, as well as those under investigation, which will change the way we manage older patients with ATTRwt cardiac amyloidosis in the coming years.

Transthyretin Amyloid Cardiomyopathy: JACC State-of-the-Art Review

Transthyretin amyloid cardiomyopathy (ATTR-CM) is an under-recognized cause of heart failure (HF) in older adults, resulting from myocardial deposition of misfolded transthyretin (TTR) or pre-albumin. Characteristic patterns of echocardiography and cardiac magnetic resonance can strongly suggest the disease but are not diagnostic. The diagnosis can be made with noninvasive nuclear imaging when there is no evidence of a monoclonal protein. Amyloid fibril formation results from a destabilizing mutation in hereditary ATTR amyloidosis (hATTR) or from an aging-linked process in wild-type ATTR amyloidosis (wtATTR). Recent studies have suggested that up to 10% to 15% of older adults with HF may have unrecognized wtATTR. Associated features, including carpal tunnel syndrome and lumbar spinal stenosis, raise suspicion and may afford a means for early diagnosis. Previously treatable only by organ transplantation, pharmaceutical therapy that slows or halts ATTR-CM progression and favorably affects clinical outcomes is now available. Early recognition remains essential to afford the best treatment efficacy.