Abstract 18673: Lack of Influence of Comorbidities on NT Pro-BNP/BNP Ratio in ATTR-CA: A Prospective, Single Sample, Paired Data Analysis

Abstract

Introduction: Scores to stage amyloidosis include laboratory values of NT pro-BNP and BNP. However, no prior data on the correlation between the two markers is available for the same sample in ATTR patients with a spectrum of co-morbidities. While established staging systems for cardiac amyloidosis use NT-pro BNP, many centers routinely measure BNP. To facilitate universal staging, we explored the relationship between NT-pro BNP and BNP measured from a single blood sample in ATTR patients with a spectrum of co-morbidities. Hypothesis: The ratio of NT pro-BNP to BNP is influenced by atrial fibrillation, BMI, left ventricular and renal function. Methods: ATTR-CA patients had serial NT pro-BNP and BNP measured from a SINGLE blood sample. Ratios were compared in patients stratified by co-morbidities. A regression equation to derive BNP from NT pro- BNP was created. Results: Among 101 patients, (85% men, 84% Caucasian), co-morbidities were prevalent (atrial fibrillation: 56%, LVEF < 50%: 46%, GFR <60 mL/min/1.73 m 2 : 51%, BMI ≥ 27: 51%); 4% were on ARNI. A strong correlation (r = 0.83) and a ratio of the log transformed data of 1.32 (95% CI: 1.29 - 1.34) was found between NT-pro BNP and BNP levels, which was not different among patients stratified according to co-morbidities. The relationship between NT pro-BNP and BNP was defined by ln(BNP) = 0.59 + 0.69 ln(NT pro-BNP). Conclusions: Our study suggests a robust correlation between NT-pro BNP and BNP in ATTR-CA patients and a constant ratio among patients with different co-morbidities. A regression equation may facilitate deriving BNP levels from NT- pro BNP and must be validated independently.