Abstract
Background
Skeletal muscle dysfunction is an important emerging complication of IPAH that impacts negatively on exercise tolerance and quality of life (1).
Aims and methods
We aimed to determine the relationship between muscle dysfunction, markers of exercise tolerance (6MWT) and physical activity in patients with IPAH. As part of an on-going study, nine patients with IPAH underwent physiological tests and physical activity monitoring using the Sensewear armband.
Results
All patients were in WHO group I-III. There were statistically significant correlations between distance achieved on 6MWT and ultrasound measured quadriceps cross sectional area (USQCSA) (r = 0.74 p = 0.02) quadriceps maximal volitional capacity (QMVC)/BMI (r = 0.67 p < 0.05), and fat free mass index (FFMI) (r = 0.76, p = 0.02) (Figure 1A-C). Physical activity correlated less clearly with 6MWT. However there was an emerging trend in correlation between 6MWT and steps per day (r = 0.70, p = 0.05).
Discussion
Interestingly USQCSA, QMVC/BMI and FFMI all correlated with 6MWT distance in IPAH. Physical activity parameters were less clearly associated with exercise tolerance in our group, although this is probably due to the small numbers recruited into the study. Further investigation of muscle weakness and physical activity as potential targets for intervention in PAH are warranted.
1. Mainguy et al. Thorax 2010.
- © 2014 ERS