Maximal exercise capacity and peripheral skeletal muscle function following lung transplantation

Area of Science:

• Cardiopulmonary Exercise Physiology
• Transplantation Medicine
• Skeletal Muscle Physiology

Background:

• Diminished exercise capacity post-lung transplantation is often attributed to peripheral muscle dysfunction.
• Limited data exists on skeletal muscle function in lung transplant recipients, particularly beyond 18 months post-procedure.

Purpose of the Study:

• To quantify skeletal muscle function and cardiopulmonary responses to graded exercise in lung transplant recipients.
• To compare outcomes between single-lung (SLT) and double-lung (DLT) transplantation groups.

Main Methods:

• 19 lung transplant recipients (10 SLT, 9 DLT) underwent spirometry, lung volume assessment, respiratory muscle strength testing, and progressive cycle ergometer testing.
• Cardiac output, peripheral muscle power, and work capacity were measured using isokinetic cycling.

Main Results:

• Both SLT and DLT groups showed equally limited exercise capacity (Wmax) and reduced leg power and work capacity, irrespective of time post-transplant.
• Despite better lung function (FEV1) in DLT, exercise limitations and preserved respiratory muscle strength were similar between groups.
• Wmax correlated strongly with leg work capacity, leg power, and lung function parameters (FEV1, RV/TLC).

Conclusions:

• Reduced peripheral skeletal muscle work capacity is a primary limitation to exercise performance after lung transplantation.
• The findings suggest that detraining is the main contributor to muscular dysfunction, as respiratory muscle strength is maintained.
• Further research is needed to clarify the exact causes of muscular dysfunction post-transplantation.