Comparative Value of NYHA Functional Class and Quality-of-Life Questionnaire Scores in Assessing Heart Failure

In Brief PURPOSE To assess the relationships between New York Heart Association (NYHA) functional class, quality of life, aerobic capacity (peak oxygen uptake, V̇O2), ventilatory efficiency (minute ventilation/carbon dioxide production slope, VE/V̇CO2 slope), and brain natriuretic peptide (BNP) in creating a model for predicting peak V̇O2. METHODS Cardiopulmonary exercise testing was performed in 62 patients. A baseline blood sample was taken to measure the N-terminal prohormone BNP (NT-proBNP). Patients also completed the Minnesota Living with Heart Failure Questionnaire (MLHF) and the Specific Activity Questionnaire (SAQ), and NYHA functional class was determined. RESULTS NYHA functional class correlated more strongly with SAQ score than with MLHF score. Peak V̇O2 and VE/V̇CO2 slope had stronger associations with NYHA functional class and SAQ score than with MLHF score. NT-proBNP plasma levels correlated more significantly with NYHA functional class and SAQ score (both P < .001) than with MLHF score. Using multiple linear regression analysis adjusted for age and sex, SAQ score, NT-proBNP, and etiology of heart failure had significant independent relationships with peak V̇O2, explaining 63% of its variability (adjusted R2 = 0.596). CONCLUSIONS Cardiopulmonary exercise variables and plasma NT-proBNP are associated more with NYHA functional class and SAQ score than with MLHF score. When combined, SAQ score, NT-proBNP, and etiology of heart failure can satisfactorily predict peak oxygen uptake. This study identified significant correlations among New York Heart Association functional class, quality of life, aerobic capacity, ventilatory efficiency, and brain natriuretic peptide (BNP). In addition, a model was created for predicting aerobic capacity using the Specific Activity Questionnaire score, plasma N-terminal prohormone BNP levels, and etiology of heart failure.