0353: Prevalence of hereditary transthyretin cardiac amyloidosis in patients with increase in LV thickness in France

Background Hereditary transthyretin cardiac amyloidosis (mTTR-CA) is a hypertrophic cardiomyopathy with challenging diagnosis and poor prognosis. The prevalence of m-TTR in patients with increased left ventricular wall thickness (LVWT) is unknown. Methods Prospective and consecutive multicenter study with systematic genetic screening for mTTR in adult patients with LVWT ≥15mm included in cardiology primary clinics. Results 298 patients were genotyped of whom 23% were African descendant. The median (IQR) age was 62(50,74), 74% were men and 36% were in NYHA class III-IV. The median of maximal LV thickness was 18 (16, 21)mm.17 patients had TTR mutation (5.7%) of whom 15 (5.0) had confirmed mTTR-CA. All the mTTR-CA were ≥55years meaning that the prevalence of mTTR-CA was 8.3% above this age. Of the 15 with mTTR-CA, 8 were Africans and 6 Caucasians. In Africans ≥55 years, the prevalence was 22% and reached 35% in those over 65 years. The most frequent mutations were V142I (8), V50M (2) and I127V (2). When adjusted to age, neuropathy (OR=20.1; 95%-CI, 5.86-69.4; P