Endomyocardial Biopsy Characterization of Heart Failure With Preserved Ejection Fraction and Prevalence of Cardiac Amyloidosis

OBJECTIVES This study prospectively evaluated endomyocardial biopsies in patients with heart failure with preserved ejection fraction (HFpEF) to identify histopathotogic phenotypes and their association with clinical characteristics. BACKGROUND Myocardial tissue analysis from a prospectively defined HFpEF cohort reflecting contemporary comorbidities is lacking. METHODS Patients with HFpEF (EF >= 50%) referred to the Johns Hopkins HFpEF Clinic between August 2014 and September 2018 were enrolled for right heart catheterization and endomyocardiat biopsy. Clinical features, echocardiography, hemodynamics, and tissue histology were determined and compared with controls (unused donor hearts) and HF with reduced EF (HFrEF). RESULTS Of the 108 patients enrolled, median age was 66 years (25th to 75th percentile: 57 to 74 years), 61% were women, 57% were African American, 62% had a previous HF hospitalization, median systolic blood pressure was 141 mm Hg (25th to 75th percentile: 125 to 162 mm Hg), body mass index (BMI) was 37 kg/m(2) (25th to 75th percentile: 32 to 45 kg/m(2)), and 97% were on a loop diuretic. Myocardial fibrosis and myocyte hypertrophy were often present (93% and 88%, respectively); however, mild in 71% with fibrosis and in 52% with hypertrophy. Monocyte infiltration (CD68-rcells/mm(2)) was greater in patients with HFpEF versus controls (60.4 cells/mm(2) [25th to 75th percentile: 36.8 to 97.8] vs. 32.1 cells/mm(2) [25th to 75th percentile: 22.3 to 59.2]; p = 0.02) and correlated with age and renal disease. Cardiac amytoidosis (CA) was diagnosed in 15 (14%) patients (HFpEF-CA: 7 patients with wild-type transthyretin amytoidosis (ATTR], 4 patients with hereditary ATTR, 3 patients with tight-chain amytoidosis, and 1 patient with AA (secondary) amytoidosis), of which 7 cases were unsuspected. Patients with HFpEF-CA were older, with tower BMI, higher left ventricular mass index, and higher N-terminal pro 8-type natriuretic peptide and troponin 1 levels. CONCLUSIONS In this large, prospective myocardial tissue analysis of HFpEF, myocardial fibrosis and hypertrophy were common, CD68+ inflammation was increased, and CA prevalence was 14%. Tissue analysis in HFpEF might improve precision therapies by identifying relevant myocardial mechanisms. (C) 2020 Published by Elsevier on behalf of the American College of Cardiology Foundation.