Factors Related to 6-Minute Walk Distance in Pulmonary Arterial Hypertension

Abstract

Objective: The 6-minute walk test is the most commonly used tool for evaluating prognosis in patients with
pulmonary arterial hypertension (PAH). This study aims to identify the parameters associated with 6-minute
walk distance (6MWD) and its changes over time.

Methods: Sixty-three patients diagnosed with PAH or chronic thromboembolic pulmonary hypertension
between January 2005 and January 2013 were included in the study. Demographic, clinical, echocardiographic, hemodynamic data, and initial and follow-up 6MWD were recorded. The 6MWD cut-off was
determined based on previous studies. Patients were then categorized into groups based on their initial
6MWD: ≥ 332 m or < 332 m.

Results: Patients were followed up for 31.56 ± 15.07 months. In those with a 6MWD < 332m, diffusing
capacity of the lungs for carbon monoxide (DLCO) (P = .040), estimated glomerular filtration rate (P = .018),
and partial arterial oxygen pressure (PaO2) (P = .024) were significantly lower, whereas age (P = .016), right
atrial pressure (P = .034), the frequency of pericardial effusion (P = .004), and mortality (P = .020) were
significantly higher. Low DLCO was identified as an independent predictor of walking less than 332 meters
(P = .048). In the subgroup analysis, among idiopathic PAH (IPAH) patients, DLCO (P = .024) was lower in
those with 6MWD < 332 m. In patients with scleroderma-associated PAH (SSc-PAH), systolic pulmonary
artery pressure (sPAP) (P = .018), and mean PAP (p = 0.034) were higher in patients with 6MWD < 332 m.
When the change in 6MWD (Δ6MWD) was evaluated based on the difference between the initial 6MWD
and at the end of the follow-up period, DLCO was lower in the group with a decreased 6MWD (P < .001).

Conclusion: The study identified higher DLCO as an independent predictor of 6MWD ≥ 332 m and its
improvement over time. In IPAH, 6MWD is more closely associated with DLCO and PaO2, whereas in SScPAH, PAPs play a more significant role.

Cite this article as: Yurtseven E, Özcan S, Karadağ B, Öngen HG, Öngen Z. Factors related to 6-minute walk distance in pulmonary
arterial hypertension. Cerrahpaşa Med J 2025, 49, 0015, doi: 10.5152/cjm.2025.25015.