The heart supplies the organs with oxygen and nutrient-rich blood. During exercise, the heart
adapts by increasing the rate of contraction and the rate of blood flow.
Heart failure occurs when the heart loses its muscular strength and its normal capacity to
contract; it no longer pumps enough blood to allow the organs to receive enough oxygen and
nutrients, which are essential for their proper functioning.
This syndrome is frequent and serious with a prevalence of 2 to 3% in Europe and a high
morbidity and mortality (1st cause of hospitalization with more than 150,000 hospitalizations
per year in France, a mortality of 50% at 5 years, i.e. more than most cancers). This
mortality is even higher in the West Indies, with an excess of premature mortality related to
heart failure of +32.9% in Martinique and +86.9% in Guadeloupe compared with metropolitan
France (average annual mortality rate for heart failure in 2008-2010 per 100,000 in habitants
under 65 years of age).
Some studies have indeed shown a higher prevalence of heart failure in the Afro-Caribbean and
Afro-American population with etiologies that differ from the Caucasian population. Among
them, transthyretin (TTR) amyloidosis is rare in Europe but very common in African
descendants with a prevalence of 3.4% of a transthyretin gene mutation (V122l) in this
population (likely to induce hereditary amyloidosis after the fifth decade). It is a serious
disease with a median survival of 2 to 6 years depending on the study and is often
under-diagnosed with late detection at the time of a major cardiovascular event, such as a
stroke or acute heart failure. Screening is done by imaging (cardiac MRI or bone scintigraphy
with labelled diphosphonates). According to a study carried out in the Cardiology Department
of the Martinique University Hospital (TEAM Amyloidosis study), one out of three left
ventricular hypertrophy (LVH) (parietal thickness ≥ 15 mm), diagnosed by echocardiography, is
amyloidosis. A study published by Thibaud Damy's team in 2015 already found a 5% prevalence
of TTR gene mutation in patients with LVH. It is now accepted that systematic screening for
amyloidosis is necessary in cases of LVH > 12 mm associated with at least one risk factor for
amyloidosis ("red flags") in order to implement appropriate therapies and thus improve
patient survival.
The study by Dungu et al. reports that cardiac amyloidosis is an underestimated etiology of
acute heart failure in Afro-Caribbean immigrants in London. The study found a high prevalence
of cardiac amyloidosis at 11.4% among 211 African-Caribbean immigrants compared to a
Caucasian population (1.6%), with a higher mortality of these patients compared to patients
with another cause of heart failure (median survival 2.3 years versus 7 years for other
etiologies). The study by Arvanitis et al. describes a 5.1% prevalence of the transthyretin
gene mutation (V122l) in 101 African Americans with heart failure (compared to 8.5% of
mutation carriers among African-Caribbean immigrants in the Dungu study).
In these two studies, the prevalences of amyloidosis and the V122I mutation are probably
underestimated, given the absence of systematic screening of all heart failure cases and the
fact that only patients with left ventricular hypertrophy on transthoracic echography were
targeted.
In addition, amyloidosis can take different forms from those usually described. Occasional
observations in our experience at the University Hospital of Martinique have found cases of
heart failure with dilated cardiomyopathy (DCM), associated with transthyretin cardiac
amyloidosis. Several similar observations have been found in the literature.
The study hypothesise is that cardiac amyloidosis is as common, or more common, in acute
heart failure in the French West Indies than elsewhere. A systematic screening for
amyloidosis in all patients with acute heart failure would allow early initiation of
appropriate treatment and improve their long-term outcome.