Neuropathy in Patients Monitored for Wild-type TTR Cardiac Amyloidosis (Non-mutated)
Condition: Wild-type Amyloid Cardiopathy
MeSH terms: Heart Diseases; Amyloidosis
Study type: Interventional

Summary: 
      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.
    

Detailed description: 
      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.
    

Intervention name(s): electromyogram
Intervention type(s): Procedure
Intervention description(s): Patients meeting the criteria will be seen in consultation with standardized interview and clinical examination. An electromyogram will be then carried out to check for the presence of neuropathy. Finally, for patients diagnosed with neuropathy, a biological check-up to look for another cause of neuropathy will be performed. In patients who already had an EMG as part of their medical follow-up, the examination will not be repeated if it strictly meets the conditions of the minimum protocol and if it was done within the year prior to inclusion. In patients who already had an identical biological assessment in the year prior to inclusion, the sample will not be taken.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Diagnostic
Keywords: wild-type amyloid cardiopathy; neuropathy; descriptive study