Pulmonary Rehab in Chronic Obstructive Pulmonary Disease (COPD): Response to Tyvaso

Study Hypothesis: Our hypothesis is that pre-treating patients with COPD with inhaled treprostinil prior to pulmonary rehabilitation sessions will result in improved exercise tolerance during sessions. This in turn will lead to an increased response to pulmonary rehabilitation, resulting in improved exercise tolerance and quality of life. Study Background: Pulmonary rehabilitation (PR) is a widely accepted intervention in patients with advanced COPD. This has consistently been shown to improve patients' quality of life and functional ability. Indeed, enrollment and completion of a course of PR is a prerequisite prior to major interventions such as lung volume reduction surgery or transplantation. A typical course of PR includes 20 sessions of supervised exercise and educational activity over an 8 week period. Sessions are usually held three times per week and last between 2-3 hours each. Most patients with COPD will have a ventilatory limitation to exercise and while many are oxygen dependent, a minority of patients will have a true hypoxic limitation to exercise. Nonetheless, when patients with COPD are ambulated on oxygen they feel better and walk further. Indeed, supplemental oxygen remains one of the few interventions that have been demonstrated to be associated with improved survival in patients with COPD. There have been a few studies and case reports utilizing inhaled pulmonary vasodilators in patients with COPD, although none to date have used treprostinil. One study of 10 patients with COPD and pulmonary hypertension found improved gas exchange and exercise tolerance following using of inhaled iloprost an alternative inhaled pulmonary vasodilator. No adverse effects were observed. \[Dernaika TA, Beavin M, Kinasewitz GT. Iloprost improves gas exchange and exercise tolerance in patients with pulmonary hypertension and chronic obstructive pulmonary disease. Respiration; 2010: 79(5): 377-382.)\] A case report of a patient with pulmonary hypertension and COPD found sustained improvements in exercise tolerance with regular use of inhaled iloprost. \[Hegewald MJ, Elliott CG. Sustained improvement with iloprost in a COPD patient with severe pulmonary hypertension. Chest 2009; 135(2): 536-537.\] While these limited trials support the concept of physiologic improvement with use of inhaled pulmonary vasodilators in COPD, our study differs from these in several important ways. This study is unique in that there has never been a prior similar study of medication pretreatment prior to PR to enhance exercise performance in any patient subgroup. Furthermore, treprostinil has not yet been evaluated for use on an as needed basis. Indication Studied: COPD/Pulmonary rehabilitation Study Objectives: * Primary Objective: To determine the effect of inhaled treprostinil, administered prior to pulmonary rehabilitation sessions, on the six minute walk test distance (6MWT) in COPD patients after completing an 8 week course of pulmonary rehabilitation * Secondary Objectives: To assess the effect inhaled treprostinil, administered prior to pulmonary rehabilitation in COPD patients, on secondary outcomes including quality of life (as measured by the St. George's respiratory questionnaire, Clinical COPD Questionaire), BODE index, lowest nadir of oxygen saturation on 6 minute walk test, number of exacerbations, ER visits, hospitalizations, and change in measures of strength training. Trial Design: An adaptive, prospective, randomized, double-blind, placebo-controlled study of 34 patients with advanced COPD who have been referred for pulmonary rehabilitation. All patients will be screened at baseline with an arterial blood gas. A test dose of inhaled nitric oxide (NO) will be administered to all subjects for 2-5 minutes. An ABG will then be repeated. Patients who have a worsened A-a gradient will be screened out. Patients will be randomized to receive one dose of inhaled treprostinil or placebo prior to each of their exercise sessions. All patients will be pretreated with albuterol prior to the dose of inhaled treprostinil (or placebo). Patient Population: We plan to screen 50 patients with a goal of enrolling 34 patients. Patients referred for pulmonary rehabilitation at Inova Fairfax Hospital with moderate to severe COPD as a primary diagnosis will be screened for inclusion in the trial. Inclusion and exclusion criteria are listed below.