Valvular heart disease in patients with cardiac amyloidosis

Diagnostic and therapeutic challenges in rapidly progressing cardiac amyloidosis: a literature review based on case report

INTRODUCTION

Cardiac amyloidosis is a rarely reported and potentially fatal variant of the systemic disease. Its early diagnosis could potentially lead to significantly improved clinical outcomes.

CASE PRESENTATION

A 56-year-old female presented with dyspnea and palpitations. Her physical exam and non-invasive evaluation with cardiac magnetic resonance imaging (CMRI) revealed restrictive cardiomyopathy, and the bone marrow biopsy results showed systemic amyloidosis.

DISCUSSION

The diagnosis of cardiac amyloidosis is not always straightforward, and delay can cause the progression of the disease and an increased risk of morbidity and mortality. Electrocardiograms, echocardiograms, cardiac magnetic resonance imaging, and histopathologic evaluation are the main methods for diagnosing cardiac amyloidosis. The treatment consists of controlling heart failure symptoms and disease-modifying interventions, including medical and surgical therapeutic methods.

CLINICAL LEARNING POINT (CONCLUSION)

Cardiac involvement is the main cause of death in systemic amyloidosis. Early suspicion, diagnosis, and treatment are crucial in improving patients' survival. CMRI can play an essential role in the diagnosis of cardiac Amyloidosis. A graphical abstract is provided for visual summary.

Thromboembolic and bleeding risk in cardiac amyloidosis

Cardiac amyloidosis represents a spectrum of conditions characterized by the accumulation of insoluble fibrils, resulting in progressive deposition and myocardial dysfunction. The exact mechanisms contributing to the heightened risk of thromboembolic events and bleeding tendencies in cardiac amyloidosis remain unclear. Proteins such as transthyretin in transthyretin amyloidosis and light chains in light-chain amyloidosis, along with acute phase proteins in amyloid A (AA) amyloidosis, play complex roles in the coagulation cascade, affecting both coagulation initiation and fibrinolysis regulation. The increased occurrence of atrial fibrillation, systolic and diastolic left ventricular dysfunction, and atrial myopathy in patients with cardiac amyloidosis may predispose them to thrombus formation. This predisposition can occur regardless of sinus rhythm status or even with proper anticoagulant management. Bleeding events are often linked to amyloid deposits around blood vessels, which may increase capillary fragility and cause coagulation disturbances, leading to unstable international normalized ratio levels during anticoagulant therapy. Thus, comprehensive risk assessment for both thrombotic and hemorrhagic complications, especially before commencing anticoagulant therapy, is imperative. This review will explore the essential pathophysiological, epidemiologic, and clinical aspects of thromboembolic and bleeding risk in cardiac amyloidosis, evaluating the existing evidence and uncertainties regarding thrombotic and bleeding risk assessment and antithrombotic treatment.

Current Therapies and Future Horizons in Cardiac Amyloidosis Treatment

PURPOSE OF REVIEW

Cardiac amyloidosis (CA) is a condition characterized by misfolding and extracellular deposition of proteins, leading to organ dysfunction. While numerous forms of CA exist, two subtypes dominate clinical prevalence: Transthyretin amyloid (ATTR) and immunoglobulin light chain amyloid.

RECENT FINDINGS

The current scientific landscape reflects the urgency to advance therapeutic interventions with over 100 ongoing clinical trials. Heart failure treatment is affected by CA phenotype with poor tolerance of otherwise frequently used medications. Treating comorbidities including atrial fibrillation and valvular disease remains a challenge in CA, driven by technical difficulties and uncertain outcomes. Tafamidis is the first ATTR-stabilizer approved with a rapidly growing rate of clinical use. In parallel, various new therapeutic classes are in late-stage clinical trials including silencers, antibodies and genetic therapy. Managing CA is a critical challenge for future heart failure care. This review delineates the current standard-of-care and scientific landscape of CA therapy.

Myocardial Mechanics and Valvular and Vascular Abnormalities in Cardiac Amyloidosis

Cardiac amyloidosis is an infiltrative disease primarily caused by extracellular tissue deposition of amyloid fibrils in the myocardial interstitium. The aim of the present review was to summarize findings regarding changes in myocardial mechanics, valvular abnormalities, and vascular remodeling detected in patients with cardiac amyloidosis.

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.

Prevalence and clinical outcomes of isolated or combined moderate to severe mitral and tricuspid regurgitation in patients with cardiac amyloidosis

AIMS

Evidence on the epidemiology and prognostic significance of mitral regurgitation (MR) and tricuspid regurgitation (TR) in patients with cardiac amyloidosis (CA) is scarce.

METHODS AND RESULTS

Overall, 538 patients with either transthyretin (ATTR, n = 359) or immunoglobulin light-chain (AL, n = 179) CA were included at three Italian referral centres. Patients were stratified according to isolated or combined moderate/severe MR and TR. Overall, 240 patients (44.6%) had no significant MR/TR, 112 (20.8%) isolated MR, 66 (12.3%) isolated TR, and 120 (22.3%) combined MR/TR. The most common aetiologies were atrial functional MR, followed by primary infiltrative MR, and secondary TR due to right ventricular (RV) overload followed by atrial functional TR. Patients with isolated or combined MR/TR had a more frequent history of heart failure (HF) hospitalization and atrial fibrillation, worse symptoms, and higher levels of NT-proBNP as compared to those without MR/TR. They also presented more severe atrial enlargement, atrial peak longitudinal strain impairment, left ventricular (LV) and RV systolic dysfunction, and higher pulmonary artery systolic pressures. TR carried the most advanced features. After adjustment for age, sex, CA subtypes, laboratory, and echocardiographic markers of CA severity, isolated TR and combined MR/TR were independently associated with an increased risk of all-cause death or worsening HF events, compared to no significant MR/TR [adjusted HR 2.75 (1.78-4.24) and 2.31 (1.44-3.70), respectively].

CONCLUSION

In a large cohort of patients with CA, MR, and TR were common. Isolated TR and combined MR/TR were associated with worse prognosis regardless of CA aetiology, LV, and RV function, with TR carrying the highest risk.

Cardiac Amyloidosis and Valvular Heart Disease

Growing interest has accrued in the co-existence of cardiac amyloidosis and valvular heart disease. Amyloid infiltration from either transthyretin (ATTR) or of light chain (AL) origin may affect any structure of the heart, including the valves. The recent literature has mainly focused on aortic stenosis and cardiac amyloidosis, improving our understanding of the epidemiology, diagnosis, treatment and prognosis of this dual pathology. Despite being of high clinical relevance, data on mitral/tricuspid regurgitation and cardiac amyloidosis are rather scarce and mostly limited to case reports and small cases series. It is the aim of this review article to summarize the current evidence of concomitant valvular heart disease and cardiac amyloidosis by including studies on epidemiology, diagnostic approaches, screening possibilities, therapeutic management, and prognostic implications.