Breath analysis in pulmonary arterial hypertension

Area of Science:

• Biochemistry
• Pulmonary Medicine
• Analytical Chemistry

Background:

• Pulmonary arterial hypertension (PAH) is a progressive vascular disease linked to metabolic abnormalities.
• Metabolic derangements in PAH patients are hypothesized to be detectable through breath analysis.
• Investigating breath volatile organic compounds (VOCs) may reveal novel biomarkers for PAH.

Purpose of the Study:

• To determine if metabolic by-products in exhaled breath can identify patients with pulmonary arterial hypertension (PAH).
• To analyze breathprints of PAH patients and healthy controls using selected ion flow tube-mass spectrometry (SIFT-MS).
• To identify specific volatile organic compounds (VOCs) that differ between PAH patients and controls.

Main Methods:

• Breath and blood samples were collected from PAH patients (n=31) and healthy controls (n=34).
• Breath analysis was performed using selected ion flow tube-mass spectrometry (SIFT-MS) in training and validation cohorts.
• Discriminant analysis identified key ion peaks and variables for classification, with subsequent VOC concentration comparisons.

Main Results:

• A discriminant model using three ion peaks and age achieved 88.9% classification accuracy in the training set and 82.8% in the validation set.
• Significant differences in concentrations of VOCs including 2-propanol, acetaldehyde, ammonia, ethanol, pentane, 1-decene, 1-octene, and 2-nonene were observed between PAH patients and controls.
• Exhaled ammonia levels were significantly higher in PAH patients (94.7 ppb vs 60.9 ppb, P<.001) and correlated with disease severity markers.

Conclusions:

• Distinct breathprints differentiate patients with pulmonary arterial hypertension (PAH) from healthy individuals.
• Specific compounds, notably ammonia, are elevated in the breath of PAH patients.
• Exhaled ammonia levels show a significant correlation with the severity of PAH, suggesting its potential as a biomarker.