Comparative value of NYHA functional class and quality-of-life questionnaire scores in assessing heart failure.

PURPOSE: To assess the relationships between New York Heart Association (NYHA) functional class, quality of life, aerobic capacity (peak oxygen uptake, (.)VO2), ventilatory efficiency (minute ventilation/carbon dioxide production slope, VE/(.)VCO2 slope), and brain natriuretic peptide (BNP) in creating a model for predicting peak (.)VO2).
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 (.)VO2 and VE/(.)VCO2 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 (.)VO2, explaining 63% of its variability (adjusted R(2) = 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.