Chest. 2010 Jun;137(6):1297-303. Epub 2010 Jan 29.
Characterization of pulmonary arterial hypertension patients walking more than 450 m in 6 min at diagnosis.
Degano B, Sitbon O, Savale L, Garcia G, O'Callaghan DS, Jaïs X, Humbert M, Simonneau G.
Service de Pneumologie, Hôpital Antoine-Béclère, 157 rue de la Porte de Trivaux, 92141 Clamart, France.
Abstract
BACKGROUND: At diagnosis of pulmonary arterial hypertension (PAH), some patients are considered to have a "near-normal" 6-min walk distance (6MWD) (ie, > 450 m). Because they are generally excluded from randomized controlled trials, little is known about these patients.
METHODS: We analyzed the baseline characteristics and treatment responses of 49 consecutive patients with a 6MWD > 450 m at the time of newly diagnosed PAH. Data from this cohort were then compared with data from hemodynamically matched patients with a 6MWD < or = 450 m.
RESULTS: Patients with a 6MWD > 450 m were either in World Health Organization (WHO) functional class (FC) II (n = 23) or III (n = 26) at baseline. Compared with patients in FC II, those in FC III had more severe hemodynamic impairment (ie, a lower cardiac index and higher pulmonary vascular pressures and resistance) but similar 6MWD. At first evaluation after initiation of PAH-specific treatment (3-6 months), FC improved (FC I-II: n = 38; FC III: n = 11, P < .005) and cardiac index increased. However, 6MWD remained unchanged. Compared with matched patients with a 6MWD < or = 450 m (n = 98), individuals with a 6MWD > 450 m were approximately 9 years younger (P = .0006) and had a lower BMI (P = .0009).
CONCLUSIONS: Anthropometric characteristics such as younger age and lower BMI may explain higher 6MWD in some PAH patients. In the cohort of patients with a 6MWD > 450 m, hemodynamic indices and WHO FC were more sensitive than 6MWD in detecting changes secondary to PAH-specific treatments.
Comment in Chest. 2010 Jun;137(6):1258-60.
PMID:20118205