tafamidis and Immunoglobulin-Light-chain-Amyloidosis

Cardiac amyloidosis is an underrecognized cause of heart failure. We review clinical clues to the diagnoses, a rational approach to testing, and current and emerging therapies.. Advances in the diagnosis of amyloid cardiomyopathy include (1) use of

Topics: Amyloid Neuropathies, Familial; Amyloidosis; Benzoxazoles; Cardiomyopathies; Heart Failure; Humans; Immunoglobulin Light-chain Amyloidosis

Amyloidosis is a group of diseases that includes Alzheimer's disease, prion diseases, transthyretin (ATTR) amyloidosis, and immunoglobulin light chain (AL) amyloidosis. The mechanism of organ dysfunction resulting from amyloidosis has been a topic of debate. This review focuses on the ultrastructure of tissue damage resulting from amyloid deposition and therapeutic insights based on the pathophysiology of amyloidosis. Studies of nerve biopsy or cardiac autopsy specimens from patients with ATTR and AL amyloidoses show atrophy of cells near amyloid fibril aggregates. In addition to the stress or toxicity attributable to amyloid fibrils themselves, the toxicity of non-fibrillar states of amyloidogenic proteins, particularly oligomers, may also participate in the mechanisms of tissue damage. The obscuration of the basement and cytoplasmic membranes of cells near amyloid fibrils attributable to an affinity of components constituting these membranes to those of amyloid fibrils may also play an important role in tissue damage. Possible major therapeutic strategies based on pathophysiology of amyloidosis consist of the following: (1) reducing or preventing the production of causative proteins; (2) preventing the causative proteins from participating in the process of amyloid fibril formation; and/or (3) eliminating already-deposited amyloid fibrils. As the development of novel disease-modifying therapies such as short interfering RNA, antisense oligonucleotide, and monoclonal antibodies is remarkable, early diagnosis and appropriate selection of treatment is becoming more and more important for patients with amyloidosis.

Topics: Alzheimer Disease; Amyloid; Amyloid Neuropathies, Familial; Benzoxazoles; Diflunisal; Humans; Immunoglobulin Light Chains; Immunoglobulin Light-chain Amyloidosis; Immunologic Factors; Myocardium; Neuroprotective Agents; Oligonucleotides; Peripheral Nerves; Prealbumin; Prion Diseases; RNA, Small Interfering

Cardiac amyloidosis (CA) is an infiltrative and restrictive cardiomyopathy that leads to heart failure, reduced quality of life, and death. The disease has two main subtypes, transthyretin cardiac amyloidosis (ATTR-CA) and immunoglobulin light chain cardiac amyloidosis (AL-CA), characterized by the nature of the infiltrating protein. ATTR-CA is further subdivided into wild-type (ATTRwt-CA) and variant (ATTRv-CA) based on the presence or absence of a mutation in the transthyretin gene. CA is significantly underdiagnosed and increasingly recognized as a cause of heart failure with preserved ejection fraction. Advances in diagnosis that employ nuclear scintigraphy to diagnose ATTR-CA without a biopsy and the emergence of effective treatments, including transthyretin stabilizers and silencers, have changed the landscape of this field and render early and accurate diagnosis critical. This review summarizes the epidemiology, pathophysiology, diagnosis, prognosis, and management of CA with an emphasis on the significance of recent developments and suggested future directions.

Topics: Amyloid Neuropathies, Familial; Amyloidosis; Arrhythmias, Cardiac; Benzoates; Benzoxazoles; Biopsy; Cardiac Pacing, Artificial; Cardiomyopathies; Diflunisal; Disease Progression; Early Diagnosis; Early Medical Intervention; Echocardiography; Electrocardiography; Heart Failure; Humans; Immunoglobulin Light-chain Amyloidosis; Immunologic Factors; Magnetic Resonance Imaging; Oligonucleotides; Prealbumin; Prognosis; Proteasome Inhibitors; Pyrazoles; Radionuclide Imaging; RNA, Small Interfering

Many patients with systemic amyloidosis are underdiagnosed. Overall, 25% of patients with immunoglobulin light chain (AL) amyloidosis die within 6 months of diagnosis and 25% of patients with amyloid transthyretin (ATTR) amyloidosis die within 24 months of diagnosis. Effective therapy exists but is ineffective if end-organ damage is severe.. To provide evidence-based recommendations that could allow clinicians to diagnose this rare set of diseases earlier and enable accurate staging and counseling about prognosis.. A comprehensive literature search was conducted by a reference librarian with publication dates from January 1, 2000, to December 31, 2019. Key search terms included amyloid, amyloidosis, nephrotic syndrome, heart failure preserved ejection fraction, and peripheral neuropathy. Exclusion criteria included case reports, non-English-language text, and case series of fewer than 10 patients. The authors independently selected and appraised relevant literature.. There was a total of 1769 studies in the final data set. Eighty-one articles were included in this review, of which 12 were randomized clinical trials of therapy that included 3074 patients, 9 were case series, and 3 were cohort studies. The incidence of AL amyloidosis is approximately 12 cases per million persons per year and there is an estimated prevalence of 30 000 to 45 000 cases in the US and European Union. The incidence of variant ATTR amyloidosis is estimated to be 0.3 cases per year per million persons with a prevalence estimate of 5.2 cases per million persons. Wild-type ATTR is estimated to have a prevalence of 155 to 191 cases per million persons. Amyloidosis should be considered in the differential diagnosis of adult nondiabetic nephrotic syndrome; heart failure with preserved ejection fraction, particularly if restrictive features are present; unexplained hepatomegaly without imaging abnormalities; peripheral neuropathy with distal sensory symptoms, such as numbness, paresthesia, and dysesthesias (although the autonomic manifestations occasionally may be the presenting feature); and monoclonal gammopathy of undetermined significance with atypical clinical features. Staging can be performed using blood testing only. Therapeutic decision-making for AL amyloidosis involves choosing between high-dose chemotherapy and stem cell transplant or bortezomib-based chemotherapy. There are 3 therapies approved by the US Food and Drug Administration for managing ATTR amyloidosis, depending on clinical phenotype.. All forms of amyloidosis are underdiagnosed. All forms now have approved therapies that have been demonstrated to improve either survival or disability and quality of life. The diagnosis should be considered in patients that have a multisystem disorder involving the heart, kidney, liver, or nervous system.

Topics: Algorithms; Benzoxazoles; Dexamethasone; Diagnosis, Differential; Gene Silencing; Heart Failure; Humans; Immunoglobulin Light-chain Amyloidosis; Liver Transplantation; Melphalan; Prognosis; Proteinuria; Stem Cell Transplantation