Measurement properties of the 6-min walk test in individuals with exercise-induced pulmonary arterial hypertension

作者：Fowler R M; Jenkins S C; Maiorana A J; Gain K R; O'Driscoll G; Gabbay E^*

来源：Internal Medicine Journal, 2011, 41(9): 679-687.

DOI：10.1111/j.1445-5994.2011.02501.x

• 6-minute walk test
• exercise-induced pulmonary arterial hypertension
• aerobic capacity
• cardiac output

Background: Exercise-induced pulmonary arterial hypertension (EIPAH) is associated with reduced peak exercise cardiac output (CO) and aerobic capacity (peak (V) over dotO(2)). We investigated the validity of the encouraged 6-min walk test (6MWT) to identify exercise limitation and estimate aerobic capacity in subjects with EIPAH.
Methods: Seventeen subjects with EIPAH (56 +/- 14 years, 15 women) and 20 healthy controls (57 +/- 13 years, 19 women) underwent two encouraged 6MWTs and a symptom-limited cardiopulmonary exercise test (CPET). To measure central haemodynamics, subjects with EIPAH performed the CPET with a pulmonary artery catheter in situ.
Results: Compared with controls, subjects with EIPAH had reduced peak (V) over dotO(2) (1.2 +/- 0.4 vs 1.7 +/- 0.5, L/min, P < 0.01), 6-min walk distance (6MWD) (575 +/- 86 vs 669 +/- 76 m, P < 0.001) and 6-min walk work (6MWW) (39 +/- 11 vs 45 +/- 7 km.kg, P < 0.01). In subjects with EIPAH, there was a moderate correlation between 6MWD and peak (V) over dotO(2) (r = 0.72, P < 0.01) and a strong correlation between 6MWW and peak (V) over dotO(2) (r = 0.86, P < 0.001). There were significant correlations between 6MWD and peak CO (r = 0.59, P < 0.05), and between peak (V) over dotO(2) and peak CO (r = 0.55, P < 0.05). Peak heart rate was similar in the CPET and 6MWT in subjects with EIPAH (133 +/- 15 vs 133 +/- 19 beats/min, P = 0.8).
Conclusions: The encouraged 6MWT identifies reduced exercise capacity and provides a valid estimate of aerobic capacity in EIPAH.

• 出版日期2011-9