Background: Life-time diagnostics of wild type transthyretin amyloidosis (ATTR(wt)-amyloidosis) is virtually absent, even though ATTR(wt)-amyloidosis is an underestimated cause for morbidity and mortality, particularly in the older age group.
Aim: To study incidence, demographic characteristics, and morpho-functional features of ATTR(wt)-amyloidosis in patients with FC IV CHF and LV hypertrophy > 15 mm according to autopsy data.
Materials and methods: Postmortem reports were retrospectively analyzed for patients (n=141; 19 % males, 81 % females) of cardiology departments aged ≥69 with the underlying CHF syndrome. From all formalin-fixed fragments of the myocardium embedded in paraffin were prepared 5-7 mkm cuts, which were stained with Congo red (Sigma, USA) and viewed under normal and polarized light. Immunohistochemical analysis was also performed using antibodies to AA-amyloid, transthyretin, kappa and lambda-light chains of immunoglobulins.
Results: deposits were found in both old and very old persons aged 91.25±9.67, mostly in women due to shorter life span of men. In different FCs associated with LV hypertrophy, according to autopsy data amyloid deposits were observed in virtually every fifth deceased (21 % of cases). The amount of myocardial amyloid deposits was generally small (56 % of cases had (+) and 27 % had (++) amyloid deposits); 17 % of cases had considerable amyloid deposits (7 % had (+++) and 10 % had (++++)). The presence of amyloid deposits did not influence indexes of myocardial hypertrophy, such as ventricular septum thickness, LV posterior wall thickness, and heart mass. In the presented cases we observed focal amyloid deposition in the myocardium typical for old age-related amyloidosis; in 97 % cases, amyloid was located in the interstitium, around cardiomyocytes and in 3 % of cases - exclusively around blood vessels.
Conclusion: ATTR (wt)-amyloidosis was detected in every fifth patient in the old and very old cohort, primarily in women (83 %), and was not diagnosed during the life time. Characteristic morphological manifestations of ATTR(wt)-amyloidosis were focal amyloid deposits mostly in the myocardial interstitium.
Keywords: wild-type transthyretin amyloidosis, senile amidoidosis, a phenocopy of hypertrophic cardiomyopathy, chronic heart failure.