Effectiveness of exhaled nitric oxide for the prediction of non-invasive left atrial pressure in older people: a cross-sectional cohort study.

Background: During left-sided heart failure (HF), left atrial and pulmonary venous pressure increase, which may lead to pulmonary congestion. Previous cohort studies, examining participants with symptomatic HF or rheumatic heart disease, suggest a relationship between increased left atrial pressure (LAP) and fractional exhaled nitric oxide (FeNO).

Aim: To examine 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.

Design & 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 males compared with females and no different in participants with asthma, chronic obstructive pulmonary disease (COPD), or those using inhaled steroids. Participants with a high E/e' (>14) were older, with a higher proportion of females than males. 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 was not found to be an accurate predictor of elevated LAP in a primary care setting.