Cardiac Amyloidosis: Pathogenesis, diagnosis, and treatment

BACKGROUND: The administrative prevalence of cardiac amyloidosis is approximately 50 per 100 000 person-years. The pathophysiology of amyloidosis involves a misfolding of proteins with a beta-pleated sheet structure. This leads to the deposition of insoluble fibrils in the interstitium, which, in turn, impair organ function and cause a variety of diseases. Systemic types are the most common, especially light-chain (AL) and transthyretin (ATTR) amyloidosis with cardiac involvement. In this article, we present the diagnostic evaluation of amyloidosis and recent developments in its treatment. METHODS: This review is based on publications retrieved by a selective search in PubMed for registry studies, meta-analyses, randomized controlled trials, systematic reviews, guidelines, and current position papers on "cardiac amyloidosis," "ATTR amyloidosis," "cardiac amyloidosis epidemiology," "cardiac amyloidosis treatment," and "ATTR amyloidosis treatment." RESULTS: Cardiac amyloidosis markedly impairs cardiac function and carries a poor prognosis as well as elevated mortality. The diagnosis is mainly based on specialized imaging studies including echocardiography, cardiac magnetic resonance imaging, and scintigraphy. The goal of treatment is to slow amyloid deposition. In ATTR amyloidosis, transthyretin stabilizers or RNA silencers can stabilize the clinical course: the use of tafamidis has been found to be associated with better outcomes and lower overall mortality at 30 months compared with placebo (HR 0.70 [0.51; 0.96]). Vutrisiran also lowers overall mortality and reduces recurrent cardiovascular events compared to placebo (HR 0.72 [0.56; 0.93]). Cardiac complications and comorbidities can be treated, depending on left ventricular function and drug tolerability, with SGLT2 inhibitors, beta-blockers, and mineralocorticoid receptor antagonists, among other drugs. CONCLUSION: Advanced cardiac amyloidosis carries a poor prognosis; early diagnosis and targeted treatment are of decisive importance. Better outcomes are now possible with the aid of improved imaging methods, disease-modifying treatment options, and the treatment of cardiac complications. Further approaches are now being studied.