Key Information
The American College of Cardiology (ACC) has a long history of developing documents (eg, decision pathways, health policy statements, appropriate use criteria) to provide members with guidance on both clinical and nonclinical topics relevant to cardiovascular care. In most circumstances, these documents have been created to complement clinical practice guidelines and to inform clinicians about areas where evidence may be new and evolving or where sufficient data may be more limited. Despite this, numerous care gaps continue to exist, highlighting the need for more streamlined and efficient processes to implement best practices in service to improved patient care.
The systemic amyloidoses are a broad spectrum of diseases that result from misfolding of proteins that aggregate into b-sheet amyloid fibrils. Over 35 amyloidogenic precursor proteins have been identified that give rise to diseases characterized by extracellular deposition of insoluble amyloid fibrils throughout various tissues and organs. In cardiac amyloidosis, amyloid fibrils accumulate in the interstitial space between cardiac myocytes, precipitating cellular injury and impairing compliance. Advanced cardiac amyloidosis is physiologically characterized as a restrictive cardiomyopathy (CM).
The nomenclature for systemic amyloidosis includes an "A" for amyloid followed by an abbreviation of the protein that misfolds. The vast majority of encountered cases of amyloid CM will be caused by misfolding of 1 of 2 proteins: 1) monoclonal immunoglobulin light chain produced in bone-marrow plasma cell disorders; and 2) transthyretin (abbreviated TTR), also known as prealbumin, a thyroxine and retinol (vitamin A) transport protein produced by the liver (the organ principally responsible for generating circulating TTR), choroid plexus, and retinal pigmented epithelium.