Chest wall muscle area, ventilatory efficiency and exercise capacity in systemic sclerosis

Area of Science:

• Pulmonary Medicine
• Radiology
• Cardiology

Background:

• Systemic Sclerosis (SSc) can affect respiratory function.
• Interstitial Lung Disease (ILD) is a known complication, but non-ILD related factors influencing exercise capacity are less understood.
• Chest wall muscle area (CWMA) has not been extensively studied in SSc exercise capacity.

Purpose of the Study:

• To investigate the association between CWMA and exercise capacity in SSc patients without ILD.
• To determine if CWMA is a significant predictor of ventilatory efficiency and exercise performance.
• To explore the utility of HRCT-derived CWMA as a clinical assessment tool.

Main Methods:

• Forty-four SSc patients without ILD underwent chest High-Resolution Computed Tomography (HRCT) and Cardiopulmonary Exercise Testing (CPET).
• CWMA was quantified from CT images at the ninth thoracic vertebra.
• CPET parameters including maximum oxygen uptake (VO2 max) and maximum workload were analyzed.

Main Results:

• A significant positive correlation was observed between CWMA and maximum workload (r=0.470, p<0.01), VO2 max (r=0.380, p<0.01), and VO2 at anaerobic threshold (VO2@AT) (r=0.343, p<0.05).
• Multiple regression analysis indicated CWMA was a significant independent predictor of VO2 max and maximum workload.
• CWMA was also associated with tidal volume (VT) and minute ventilation (VE).

Conclusions:

• CWMA is a significant determinant of exercise capacity in SSc patients without ILD.
• HRCT-derived CWMA can serve as a valuable, non-invasive marker for assessing exercise limitations in these patients.
• This finding suggests potential therapeutic targets related to muscle strength in SSc management.