Measurement of exhaled nitric oxide fails to predict left atrial pressure assessed by E/e ratio in elderly patients.
Jones ST., Londahl M., Prothero A., Hobbs R., Pavord I., Myerson SG., Prendergast B., Coffey S.
BACKGROUND: During left-sided heart failure, left atrial and pulmonary venous pressure increase, which may lead to pulmonary congestion. Previous cohort studies examining participants with symptomatic heart failure or rheumatic heart disease suggest a relationship between increased left atrial pressure (LAP) and fractional exhaled nitric oxide (FeNO). AIM: In this study, we examined the strength of association between FeNO and echocardiographic assessment of LAP by the E/e' ratio to determine if FeNO could be used to identify those with elevated LAP. Office-based diagnostic testing for heart failure could be improved if such a relationship exists, as FeNO can be measured using a portable hand-held analyser. DESIGN AND SETTING: This cross-sectional cohort study examined a subset of the OxVALVE cohort aged >65 years. Data collection was undertaken in primary care practices in central England. METHOD: Each participant underwent a focused cardiovascular history and clinical examination. Standard transthoracic echocardiographic (TTE) assessment was performed on all participants, with the E/e' ratio calculated to obtain a validated surrogate of LAP. FeNO was measured in 227 participants. RESULTS: FeNO was higher in men and no different in participants with asthma, chronic obstructive airways disease, or using inhaled steroids. Participants with a high E/e' (>14) were older with a higher proportion of women. There was no relationship between E/e' and FeNO, either when measured as a continuous variable or in the group with high E/e'. CONCLUSION: FeNO is not an accurate predictor of elevated left atrial pressure in a primary care setting.