Our Studies | Department of Medicine | School of Medicine

Inspiratory Muscle Training for Dyspneic Patients with COPD-Heart Failure Overlap: A Multicentre, Randomized Controlled Trial

Chronic obstructive pulmonary disease (COPD) and heart failure with reduced left ventricular ejection fraction (HF) are leading causes of disability and death worldwide (1). Unfortunately, COPD and HF coexist in up to a third of elderly patients (2) making the so-called COPD-HF overlap (CHO) a major challenge to the Canadian health care system. In fact, population ageing anticipates that CHO prevalence will further increase in the next decades (3). Despite this state of affairs, the financial and humanitarian relevance of CHO has been grossly overlooked. This is particularly surprising because negative cardiopulmonary interactions are known to potentiate the deleterious consequences of each disease on quality of life and survival.(1) Breathlessness or breathing discomfort is one of the main symptoms in people with both COPD and Heart Failure. Breathing muscle training has been found to be an effective method of decreasing breathlessness, increasing physical performance and improving the quality of life in people with either COPD or Heart Failure. The main purpose of this study is to find out if breathing muscle training can relieve breathing discomfort in people with combined COPD and Heart Failure.

If you would like more information regarding this study, please contact the study coordinators: Ingrid Rafferty 613-549-6666 ext: 3197 or Luiza Castanhas 613-549-6666 ext: 3192

Does N-Acetylcysteine (NAC) Enhance Peripheral Vascular Function in Mild COPD? This study investigates the potential beneficial effects of an anti-oxidant (NAC) on microvascular function in mild COPD.

Chronic obstructive pulmonary disease (COPD) is a leading cause of disability and death in Canada. Cardiovascular diseases are the main causes of poor physical capacity and healthcare resources utilization in COPD. There is emerging evidence that these impairments have a major impact on the health of COPD patients, even when the disease did not progress to cause severe or very severe airflow obstruction. This important problem, however, is currently neglected as no specific pharmacological treatment is currently offered to fight the predations of COPD on the cardiovascular system. Recent studies indicate that vascular abnormalities are caused by circulating inflammatory substances and direct damage of the arteries by oxygen radicals (oxidative stress). Our project will be the first to test the hypothesis that N-acetylcysteine (NAC), an inexpensive over-the-counter drug with anti-inflammatory and antioxidant effects, improves systemic vascular function and physical capacity in COPD patients with mild-to-moderate airflow obstruction. Confirmation of this hypothesis will provide new evidence that pharmacological treatment for cardiovascular dysfunction at the earlier stages of COPD effectively fights a devastating consequence of this disabling disease. Thus, NAC treatment could impact directly the current model of healthcare delivery to COPD patients with mild-to-moderate airflow obstruction in Canada.

If you would like more information regarding this study, please contact the study coordinator: Luiza Castanhas 613-549-6666 ext: 3192 or Daniel Hirai 613-549-6666 ext: 3199

Novel PFTs to Assess the Pulmonary Microcirculation: This study examines the diagnostic performance of novel PFTs in a disease in which impaired pulmonary blood flow is the defining feature: pulmonary embolism.

Human life depends crucially on how well the lungs transfer oxygen from air to blood. To reach this remarkable goal, we are endowed with a delicate network of blood-containing small vessels (the lung microvasculature) closely connected to air-filled alveoli. Diseases that affect the lung microvasculature impede the normal flow of blood through the lungs leading to heart strain, poor blood oxygenation and shortness of breath. This explains why pulmonary vascular diseases are important causes of early disability and premature death in Canada. Unfortunately, it remains challenging to identify and quantify impaired lung blood flow by the currently-available “pulmonary function tests” (PFTs). Our laboratory has gained experience in novel PFTs that can potentially detect the pulmonary vascular diseases by analyzing the exhaled air. We will test, for the first time, these novel PFTs in a disease in which impaired pulmonary blood flow is the defining feature: pulmonary embolism (PE), i.e. obliteration of pulmonary vessels by blood clots. If our project proves successful, we will make an important step towards early identification of pulmonary vascular diseases which will help thousands of Canadians.

Optimizing Cardiac Rehabilitation in Chronic Heart Failure: A Randomized, Placebo-Controlled Trial of Dietary Nitrate Supplementation

Chronic heart failure (CHF) is a leading cause of prolonged suffering in Canada and worldwide. Although affecting the heart at first, it is now recognized that impaired physical capacity may be explained largely by poor blood flow to active skeletal muscle. Reductions in nitric oxide, a molecule that dilates blood vessels, contribute importantly to impaired blood flow in CHF. Unfortunately, current drug treatment has failed to reverse these impairments. Thus, there is clearly an urgent need to develop new and effective therapies for the treatment of CHF patients. Our research proposes a new therapeutic approach: nitrate supplementation. Recent studies in healthy animal models have showed that nitrate is a powerful alternative source for nitric oxide, hence permitting blood flow to increase much more during exercise. Accordingly, nitrate supplementation has been shown to improve physical capacity of patients with other chronic cardiorespiratory diseases, namely peripheral artery disease and chronic obstructive pulmonary disease. Nitrate can be supplemented via natural products (such as concentrated beetroot juice) and lacks significant adverse effects. Research on nitrate therapy holds the potential to improve physical capacity and quality of life of patients living with CHF.

Pulmonary Blood Flow in Chronic Obstructive Pulmonary Disease

The main purpose of the cardio-respiratory system (heart, lungs, and blood vessels) is simple: deliver oxygen (O2) from the air to reach every cell in the body and to transport carbon dioxide (CO2) in the opposite direction. Chronic Obstructive Pulmonary Disease (COPD) is primarily thought of as a disease of the airways & lungs, which aid the first step in moving oxygen. However, I’m more interested in the second step, where the lungs meet the blood vessels from the heart. Why? Because the lungs and blood vessels need to interact and cooperate in order for the system to function properly. As COPD progresses, cardiovascular (heart and blood vessel) comorbidities become more common. We use breathing maneuvers, NON-invasive tests, and cycling to determine how early the function of blood vessels in the lungs might become impaired. In order to do this, we compare the pulmonary blood flow response to exercise from people with healthy lungs to those with mild-to-moderate COPD.

Systemic Vascular Dysfunction in COPD Patients with Mild-Moderate Airflow Obstruction

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality throughout the world leading to large economic and social burdens. Mild-to moderate COPD represents up to 75% of COPD patients but unfortunately is often neglected in the health care system. Although COPD is characterized as a lung disease, these patients often die of cardiovascular disease. Why? Patients with COPD often have an increased risk for cardiovascular disease, though it is frequently overlooked by clinicians. It remains unknown, however, what is contributing to the increased cardiovascular risk in mild-to-moderate COPD patients. In order to investigate this issue, patients with mild-to-moderate COPD will be compared to non-smoking normal individuals. Our primary hypothesis is that COPD patients compared to normal individuals, would present with a number of cardiovascular risk factors that reduce the blood flow going to the muscles and ultimately reduce the ability to perform exercise. If our hypotheses is correct, we will demonstrate for the first time that mild-to-moderate COPD patients have an increased risk for cardiovascular disease and that begins early in the natural progression of COPD.