Contribution of <sup>99m</sup>Tc-DPD Scintigraphy in the Diagnosis of Cardiac Amyloidosis in Black Africans

Abstract

Cardiac amyloidosis presents a picture of hypertrophic cardiomyopathy with heart failure with preserved ejection fraction. It is largely underdiagnosed, especially in black Africans, and therefore falls under the category of heart disease classified as idiopathic. Light chain amyloidosis (AL) is mainly found in Caucasian subjects and the mutant variant of transthyretin (TTRm) in negroid subjects. Numerous studies have shown that ATTRm was found predominantly in black American and black British patients. In African countries the entity of idiopathic heart failure is quite important because of lack of diagnosis, ETT, MRI and immuno-histochemistry are expensive or not available. We can probably assume that the proportion of cardiac amyloidosis is quite important in black Africans. The question is if 99mTc-DPD really easy to perform, can probably help to investigate in the nuclear medicine department in Africa. No large-scale study has been able to demonstrate the prevalence or not of cardiac amyloidosis in black-African subjects and by extension reduce this nosological entity of idiopathic heart disease. The 99mTc-DPD scintigraphy using Perrugini’s visual sore allows localization and classification of amyloid damage. The mechanism of binding of 99mTc-DPD to amyloid fibril deposits is not well known, its binding to TTR-type (mutated or wild type) amyloidosis is greater than the AL variant. In the diagnostic algorithm, endomyocardial biopsy is the gold standard but remains invasive, ETT with the strain allows a presumptive diagnosis and remains an operative examination dependent and is not reproducible. Cardiac MRI allows some localization of amyloid deposits but still remains less sensitive than scintigraphy. In addition, performing the whole-body MRI is very restrictive (time, antenna change and cost). The aim of this literature review was to show the superiority of 99mTc-DPD scintigraphy compared to other diagnostic modalities and to consider its use given its simplicity when it comes to usage in Sub-Saharan Africa to diagnose the disease. cardiac amyloidosis and by extension reduce the number of cases of heart disease classified as idiopathic and thus allow early and appropriate management.