Cardiac Care of Patients with Cardiac Amyloidosis

Emerging therapeutic avenues in cardiac amyloidosis

Cardiac Amyloidosis (CA) is a toxic infiltrative cardiomyopathy occurred by the deposition of the amyloid fibres in the extracellular matrix of the myocardium. This results in severe clinical complications such as increased left ventricular wall thickness and interventricular stiffness, a decrease in left ventricular stroke volume and cardiac output, diastolic dysfunction, arrhythmia, etc. In a prolonged period, this condition progresses into heart failure. The amyloid fibres affecting the heart include immunoglobulin light chain (AL - amyloidosis) and transthyretin protein (ATTR - amyloidosis) misfolded amyloid fibres. ATTRwt has the highest prevalence of 155 to 191 cases per million while ATTRv has an estimated prevalence of 5.2 cases per million. The pathological findings and therapeutic approaches developed recently have aided in the treatment regimen of cardiac amyloidosis patients. In recent years, understanding the pathophysiology of amyloid fibres formation and mechanistic pathways triggered in both types of cardiac amyloidosis has led to the development of new therapeutic approaches and agents. This review focuses on the current status of emerging therapeutic agents in clinical trials. Earlier, melphalan and bortezomib in combination with alkylating agents and immunomodulatory drugs were used as a standard therapy for AL amyloidosis. Tafamidis, approved recently by FDA is used as a standard for ATTR amyloidosis. However, the emerging therapeutic agents under development for the treatment of AL and ATTR cardiac amyloidosis have shown a potent and rapid effect with a safety profile.

AL Amyloidosis for Cardiologists: Awareness, Diagnosis, and Future Prospects: JACC: CardioOncology State-of-the-Art Review

Amyloid light chain (AL) amyloidosis is a rare, debilitating, often fatal disease. Symptoms of cardiomyopathy are common presenting features, and patients often are referred to cardiologists. Cardiac amyloid infiltration is the leading predictor of death. However, the variable presentation and perceived rarity of the disease frequently lead to delay in suspecting amyloidosis as a cause of heart failure, leading to misdiagnoses and a marked delay in diagnosis, with devastating consequences for the patient. A median time from symptom onset to correct diagnosis of about 2 years is often too long when median survival from diagnosis for patients with AL amyloidosis and cardiomyopathy is 4 months to 2 years. The authors highlight the challenges to diagnosis, identify gaps in the current knowledge, and summarize novel treatments on the horizon to raise awareness about the critical need for early recognition of symptoms and diagnosis of AL amyloidosis aimed at accelerating treatment and improving outcomes for patients.

Cardiac amyloidosis: a review of the literature

Cardiac amyloidosis is a rare disease associated with severe morbidity and mortality. There are three main types of amyloidosis associated with cardiac involvement: light chain (AL), familial or senile (ATTR) and secondary amyloidosis (AA). Cardiac amyloidosis often results in heart failure with preserved left ventricular ejection fraction, may display echocardiographic features of restrictive cardiomyopathy associated with left ventricular hypertrophy or mimic hypertrophic obstructive cardiomyopathy. However, left ventricular systolic dysfunction and normal wall thickness can sometimes be encountered. Imaging studies (echocardiography, bone scintigraphy, cardiac magnetic resonance) and blood and urine analysis are usually the main tools for the diagnosis. Sometimes, a tissue biopsy may be necessary. Treatment, which is constantly improving, will be carried out on two fronts: treatment of the symptoms and complications that the disease already caused and prevention of additional amyloid deposits while managing the concomitant complications. The purpose of this article is to review the management of cardiac amyloidosis.

Cardiac Amyloidosis: A Rare Cause of Recurrent Chylothorax

Amyloidosis is caused by the extracellular deposition of fibrils composed of low molecular weight protein subunits. Its two main types are amyloid light chain (AL) amyloidosis and amyloid A (AA) amyloidosis (previously referred to as secondary amyloidosis). Clinical manifestations are dependent upon location, type, and amount of deposit.

We report a case of a 72-year-old female who presented to the emergency department for evaluation of cough, fatigue, and shortness of breath. Physical examination was notable for decreased breath sounds bilaterally over the lower lung fields. Computed tomography (CT) of the chest showed a large lobulated right pleural effusion and atelectasis. Two liters of milky, white pleural fluid was removed via thoracocentesis, and pleural fluid analysis was consistent with chylothorax. Over the next 10-day period, there was a reaccumulation of the pleural fluid, which required a pleural catheter placement. The patient underwent video-assisted thoracoscopic surgery with pleural and pericardial tissue biopsy that was consistent with kappa or lambda AL amyloid. Unfortunately, her respiratory status subsequently declined, requiring mechanical ventilation, and eventually leading to cardiac arrest.

Cardiac amyloidosis can rarely cause chylous ascites and chylothorax. The absence of electrocardiographic findings of left ventricular hypertrophy combined with apparent left ventricular hypertrophy on echocardiography is strongly suggestive of infiltrative cardiomyopathy such as cardiac amyloidosis. In these cases, cardiac amyloidosis should be considered in the differential diagnosis of chylothorax.

Implementing a Machine-Learning-Adapted Algorithm to Identify Possible Transthyretin Amyloid Cardiomyopathy at an Academic Medical Center

Background:

Wild-type transthyretin amyloid cardiomyopathy (ATTR-CM) is a frequently under-recognized cause of heart failure (HF) in older patients. To improve identification of patients at risk for the disease, we initiated a pilot program in which 9 cardiac/non-cardiac phenotypes and 20 high-performing phenotype combinations predictive of wild-type ATTR-CM were operationalized in electronic health record (EHR) configurations at a large academic medical center.

Methods:

Inclusion criteria were age >50 years and HF; exclusion criteria were end-stage renal disease and prior amyloidosis diagnoses. The different Epic EHR configurations investigated were a clinical decision support tool (Best Practice Advisory) and operational/analytical reports (Clarity™, Reporting Workbench™, and SlicerDicer); the different data sources employed were problem list, visit diagnosis, medical history, and billing transactions.

Results:

With Clarity, among 45 051 patients with HF, 4006 patients (8.9%) had ⩾1 phenotype combination associated with increased risk of wild-type ATTR-CM. Across all data sources, 2 phenotypes (cardiomegaly; osteoarthrosis) and 2 combinations (carpal tunnel syndrome + HF; atrial fibrillation + heart block + cardiomegaly + osteoarthrosis) generated the highest proportions of patients for wild-type ATTR-CM screening.

Conclusion:

All EHR configurations tested were capable of operationalizing phenotypes or phenotype combinations to identify at-risk patients; the Clarity report was the most comprehensive.

Cardiac amyloidosis-A review of current literature for the practicing physician

The amyloidoses are a family of diseases in which misfolded precursor proteins aggregate to form amyloid and deposit in body tissues. A very serious yet underrecognized form of this disease is cardiac amyloidosis, in which amyloid deposits into the extracellular space of the myocardium, resulting in thickening and stiffening of ventricular walls with resultant heart failure and conductive dysfunction. This review provides a discussion of the pathogenesis and clinical presentation of cardiac amyloidosis subtypes, as well as an up-to-date approach to diagnosis and treatment. Significant progress has been made in recent years regarding diagnosis and treatment of this condition, but prognosis remains heavily reliant on early detection of the disease. Two types of precursor protein are responsible for most cardiac amyloidosis cases: transthyretin amyloid, and immunoglobulin-derived light chain amyloid. An early diagnosis of cardiac amyloidosis can allow for novel treatment modalities to be initiated with the potential to improve prognosis.