Changes in Cardiac Function in COPD Patients After Administration of Budesonide/Formoterol (Symbicort®) Versus Placebo

Patients with moderate to advanced COPD are known to have static hyperinflation (at rest) as a consequence of expiratory flow limitation. Hyperinflation is easily detected by measuring lung volumes during standard pulmonary function testing. Decreased Inspiratory Capacity (IC) secondary to hyperinflation has been described as a predictor of mortality in COPD, and as a limiting factor for the maximal tidal volume attained during exercise. Hyperinflation has been linked to a low cardiac output in part by limiting left ventricular ejection fraction during exercise. Treatment with inhaled anticholinergic agents or long-acting beta agonists (LABA) and combination of the LABA formoterol and budesonide has been shown to improve IC and decrease lung hyperinflation. Bronchodilators have been shown to improve exercise endurance in COPD when combined with pulmonary rehabilitation, however the exact mechanism: improvement of lung mechanics and /or improvement in cardiac function is not well known. Impedance cardiography (ICG) has emerged as a method to measure cardiac output without the need for invasive devices. Cardiac output measurement by impedance cardiography (CO-ICG) is a valid and reproducible method. It has been shown to have good correlation with thermodilution and the direct Fick method for the measurement of stroke volume and cardiac output. In addition, the oxygen pulse, easily obtained by dividing the measured oxygen uptake by the heart rate (VO2/HR) provides an adequate reflection of cardiac stroke volume when the systemic extraction of oxygen is stable. This method has been used to evaluate the effect of static and dynamic hyperinflation on cardiac function. This pilot study is designed to be a single center (Brigham and Women's Hospital), randomized, placebo-controlled, double blind, crossover study of 14 patients (male and female 40 to 80 years old) with COPD and static hyperinflation. The primary endpoint is the measurement of stroke volume, cardiac output and oxygen pulse at rest before and after the administration of budesonide/formoterol compared to placebo.