Cardiac AL Amyloidosis (RCD code: III-3A.2a)

Abstract

Primary systemic amyloidosis (AL amyloidosis) is the most common subtype of amyloidosis in developed countries. Amyloid fibrils deposition results from an abnormal secondary structure of immunoglobulin light chains produced by a plasma cell clone. The most common accompanying plasma cell dyscrasia is monoclonal gammopathy of undetermined significance, while multiple myeloma coexists in only 10-15% of patients. The kidneys and the heart are the most frequently affected organs. Patients usually present with concentric left ventricular concentric thickening displaying a restrictive filling pattern with well-preserved systolic function. Clinical suspicion of AL amyloidosis should be raised in older adults and elderly patients with diastolic heart failure accompanied by heavy proteinuria, upon detection of thick-walled heart on echocardiography with low-voltage QRS on ECG ("red-flags" for amyloidosis"), in non-diabetic subjects with peripheral neuropathy or autonomic neuropathy, commonly with severe postural hypotension. Classical clinical stigmata, i.e. periorbital purpura, macroglossia, carpal tunnel syndrome, are not frequent (10-20%) but can guide diagnosis. In the presence of typical echocardiographic features recommended diagnostic steps include identification of monoclonal gammopathy (serum and urine immunofixation and serum free light-chain kappa to lambda ratio) and confirmation of amyloid deposition, preferentially in a non-cardiac tissue such as periumbilical fat or minor salivary glands. Bone marrow biopsy, serum calcium assay and skeletal survey are mandatory to exclude multiple myeloma. Prognosis is mainly dependent on cardiac involvement, being determined by cardiac biomarkers and the difference between involved and uninvolved light chains. Intensive chemotherapy is the therapy of choice in intermediate-risk patients with AL amyloidosis. An improved overall survival was reported in patients with a complete haematological response and an adequate cardiac response, especially a fall in circulating levels of B-type natriuretic peptides.