Inspiratory Muscle Training for Breathless Patients With Chronic Obstructive Pulmonary Disease and Heart Failure

Inspiratory Muscle Training for Dyspneic Patients With COPD-HF Overlap: a Multicenter, Randomized Controlled Trial

The purpose of this study is to determine whether inspiratory muscle training is effective to improve breathless and exercise intolerance in symptomatic patients with chronic obstructive pulmonary disease (COPD) plus chronic heart failure (HF).

Chronic obstructive pulmonary disease (COPD) and heart failure with reduced left ventricular ejection fraction (HF) are leading causes of disability and death worldwide. Unfortunately, COPD and HF coexist in up to a third of elderly patients making the so-called COPD-HF overlap (CHO) a major challenge to Health Care Systems. In addition, population ageing anticipates that CHO prevalence will further increase in the next decades.

Intolerance to exertion due to disabling breathlessness is the hallmark of COPD and HF and these abnormalities are notoriously potentiated by diseases coexistence.

The inspiratory muscles are centrally related to the pathophysiology of exertional dyspnea in COPD and HF. In both populations a higher central motor command output is required to maintain adequate force generation in the face of weaker inspiratory muscles. This information is interpreted as "shortness of breath".

There is well established evidence gained from recent meta-analyses indicating that inspiratory muscle training (IMT), as a standalone therapy, significantly improves inspiratory muscle function (strength and endurance), dyspnea during daily activities, and functional exercise capacity in COPD and HF. Previous findings indicate that reduced pressure-generating capacity reflecting inspiratory muscle weakness is frequently observed in patients with COPD-HF and related to a clinically-relevant outcome: exertional dyspnea. These findings set the scene for a randomized controlled trial to investigate the potential role of IMT in dyspnea palliation in CHO patients.

Objectives

To determine the effects of IMT on:

1. Dyspnea on daily life
2. Inspiratory muscle strength and endurance
3. Dyspnea on exertion and time to exercise intolerance

Inclusion Criteria:

• Previous diagnoses of COPD and HF under optimized clinical treatment as judged by the accompanying physician
• Reduced left ventricular ejection fraction (<50%)
• Non-reversible airway obstruction (post-bronchodilator FEV1/FVC < 0.7 and FEV1 < 80 %)
• Respiratory muscle weakness (Pi,max < 70cmH2O)
• Persistent dyspnea on daily life (Baseline Dyspnea Index focal score <or= 8).

Exclusion Criteria:

• Inability to perform exercise tests
• Diagnosed psychiatric or cognitive disorders
• Progressive neurological or neuromuscular disorders having a major impact on exercise capacity