Cardiac amyloidosis: do not forget to look for it

Abstract

Amyloidosis is a systemic disease due to buildup of protein material in the extracellular space, which can affect the heart, mainly in its light chain and transtyretin forms. Historically this condition has been considered very uncommon, and it was certainly under-diagnosed. Today is well known that in certain group of patients its prevalence is, indeed, very high (25% in patients over the age of 80 years; 32% in patients over 75 years with heart failure and preserved systolic function, and 5% in post-mortem series of hypertrophic cardiomyopathy). Some genetically determined form of transthyretin amyloidosis are quite common in certain populations, such as Caribbean origin African-Americans. The wide spectrum of signs, symptoms, and first-level tests often overlapping among various other conditions, represent a diagnostic challenge for the clinical cardiologist. The opportunity to reach the diagnosis with non-invasive testing (first and foremost scintiscan with bone markers), as well as encouraging results of newer classes of drugs, raised the interest in this condition, so far burdened by an ominous prognosis. Early diagnosis of amyloidosis should always be guided by clinical suspicion but should also be supported by a multidisciplinary approach, aimed at optimizing the prognosis of the condition. Despite the newer drugs now available, a late diagnosis affect negatively the prognosis, and the opportunity to implement disease-modifying therapies (e.g. liver transplant in ATTR, or bone marrow transplant in AL) able to cure or at least delay the progression of the disease.

Keywords: Cardiac amyloidosis; Diagnosis; Epidemiology; Heart failure; Myocardial scintiscan.

Figure 1

Typical histological aspect of myocardium with amyloidotic infiltrates: on the background, haematoxylin-eosin staining, on the upper right, yellow–green birefringence in polarized light, lower left in Congo red colour. Pathological Anatomy Archive, University of Trieste, courtesy of Prof. Bussani. In the lower right pane, myocardial hypercapacitation of the bone tracer at scintigraphy of a patient with amyloidotic cardiomyopathy from wild-type transthyretin.

Figure 2

Left: echocardiogram of a patient suffering from AL amyloidotic cardiomyopathy, apical four chambers projection. In the upper left corner, ‘bull’s eye’ representation of the longitudinal strain with the typical ‘apical sparing’ aspect. Right: cardiac magnetic resonance imaging of a patient with transthyretin amyloidotic cardiomyopathy (post-contrastographic sequence and basal short-axis section) with the typical appearance of diffuse late gadolinium subendocardial enhancement.