Neuropathy in Patients Monitored for Wild-type TTR Cardiac Amyloidosis (Non-mutated)

Prospective Study to Investigate Neuropathy in Patients Monitored for Wild-type TTR Cardiac Amyloidosis (Non-mutated)

Transthyretin (TTR) amyloidosis is a rare disabling disorder that can be hereditary or sporadic. Depending on the form, various tissues are affected. While in hereditary cases, neuropathy is predominant, cardiac impairment is the main manifestation in the sporadic form.

The main objective of this project is to evaluate the proportion of patients with neuropathy in a population of patients with a non-mutated TTR amyloid cardiopathy condition.

Transthyretin (TTR) amyloidosis belongs to a group of severe and multi-systemic diseases caused by an extracellular accumulation of fibrillar proteins arranged in beta-pleated sheets. This pathology can be hereditary (mutations in the TTR gene) or sporadic. Depending on the form, various tissues are affected: peripheral nervous system (leading to neuropathy, especially vegetative), heart, kidney... While in forms linked to TTR mutations neuropathy is the main manifestation, in the sporadic form (also called wild-type), the cardiac impairment is predominant. Other organ damages are rarely reported in this second form. In the THAOS registry (Coelho T. et al, 2013), a clinical peripheral neuropathy is reported in 28.4% out of 67 patients with the sporadic form of the disease, although the authors do not provide a precise description of the neuropathy type. We propose to prospectively study patients with a wild-type amyloid cardiopathy condition to identify and describe the associated neuropathy. A pilot study conducted at the Bordeaux University Hospital demonstrated the feasibility and interest of this research: it showed the presence of an undetermined aetiology polyneuropathy in 35.7% out of 14 patients followed for senile cardiac amyloidosis.

Tafamidis is used on familial amyloid neuropathy and a recent study shows an effect on senile amyloid cardiopathy (Maurer MS et al., 2018) which strengthens the need to determine the frequency of neuropathies associated with wild-type amyloid cardiopathy and to type them more accurately.

Inclusion Criteria:

• Patients of both gender, over 18 years old, with transthyretin amyloid cardiopathy according to one of the two American Heart Association definitions of 2016
• No mutation in the TTR gene
• Patients giving their free and informed consent to participate after information about the research
• Patients affiliated to or benefiting from a social security scheme

Exclusion Criteria:

• Patients with chronic neuropathy related to a known aetiology
• Patients under guardianship or curatorship