Lung function in relation to six-minute walk test in pulmonary hypertension

• Background: Pulmonary hypertension (PH) is a progressive disorder of the pulmonary circulation,associated with diverse medical conditions. Exercise limitation is the most prominent symptom inPH. Exercise capacity, commonly assessed through a six-minute walk test (6MWT), correlates withboth functional status and survival in PH. Few studies have analysed the relation betweenrespiratory function and exercise limitation. Therefore, we investigated the relationship betweenresting pulmonary function, exercise capacity, and exertional desaturation, assessed through the6MWT, in unselected PH patients.Methods: Fifty consecutive patients with PH diagnosis, referred for pulmonary function testing(lung volume, spirometry, and diffusing capacity for carbon monoxide (DLCO)) and 6MWT, wererecruited at Molinette University Hospital, Turin.Results: The majority of the patients (54%) had PH due to left heart disease. Airway obstruction(FEV1/VC-ratio < 0.7) was found in 46% of the patients and they performed significantly worse inthe 6MWT than unobstructed patients (307 m vs. 377 m). Patients with PH due to left heartdisease also performed significantly poorer 6MWT when airway obstruction was present (305 mvs. 389 m). Twenty-two patients (44%) presented exertional desaturation upon 6MWT. LowerDLCO divided by the alveolar volume (DLCO/VA), FEV1/VC-ratios and resting PaO2-values weresignificantly correlated with exertional desaturation after adjustments for age, sex, BMI, andsmoking habits. DLCO/VA was the main determinant of exertional desaturation in a stepwiseregression model.Conclusions: Spirometric parameters of airway obstruction were related to walk distance andexercise-induced desaturation in PH patients. This suggests a place for spirometry in clinicalmonitoring of PH patients.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Lungmedicin och allergi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Respiratory Medicine and Allergy (hsv//eng)

Nyckelord

Pulmonary hypertension; spirometry; exercise capacity; DLCO; 6MWT

Clinical Physiology

Klinisk fysiologi

Publikations- och innehållstyp

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