Cardiac Amyloidosis in HFpEF

Heart failure with preserved ejection fraction (HFpEF) accounts for half of heart failure cases with heterogenous cause and variable presentations. The diagnosis of HFpEF required clinical signs and symptoms of HF, normal left ventricular ejection fraction (LVEF) and evidence of diastolic dysfunction. No treatment has been shown in recent major clinical trials having benefits in these patients. One major reason of the poor response to medical treatment is the heterogeneity of HFpEF, which contains many different underline causes. To identify the underlying causes of HFpEF may improve the diagnosis and treatment in these patients. Age-related amyloid deposition has first been reported in 1876 and the following autopsy studies showed the prevalence of senile cardiac amyloid is up to 25%. Recently, it has been recognized that the deposits in senile cardiac amyloid are derived from wild-type transthyretin (TTR). Transthyretin amyloidosis cardiac amyloidosis (ATTR CA) is caused by myocardial deposition of misfolded transthyretin protein. There are 2 types of ATTR classified by genetic mutation including wild-type ATTR (ATTRwt) and familial cardiac amyloid caused by TTR mutation (ATTRm). Multimodality techniques have been developed to assist in the diagnosis of the diagnosis of TTR. Among them, 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (99mTc-DPD) scintigraphy is a non-invasive test and it can diagnose TTR from other cause diverse form of cardiac amyloidosis and cardiomyopathy. In the study of Gonzalez-Lopez et al, in 120 HFpEF patients, 16 (13.3%) had positive 99mTc-DPD scan. Four patients with positive 99mTc-DPD scan received endomyocardial biopsy and confirmed cardiac amyloid deposition. ATTRwt could be an important cause of HFpEF and it was often under diagnosed. A recent study in Spain reported that 13% of patents over age of 60 years with HFpEF and left ventricular wall thickness of 12mm or more had ATTRwt. However, the prevalence of ATTRwt among patients with HFpEF is not well-established in Taiwan and Asia. The aim of this study is to determine the prevalence, clinical characteristics, risk factors and outcomes of ATTRwt related HFpEF patients in Taiwan.