Oral Sildenafil for Exercise Capacity, Dyspnea and Cardiopulmonary Function in COPD

Summary

Chronic obstructive pulmonary disease (COPD) is a condition characterized by airway obstruction. Patients with COPD experience significant shortness of breath on exertion. The mechanisms responsible for shortness of breath on exertion are well understood in moderate and severe COPD, but, are poorly understood in mild COPD where symptoms appear disproportionate to the degree of airway obstruction. Mild COPD patients show an exaggerated breathing response to exercise, determined by the breathing response to carbon dioxide production (V̇E/V̇CO2). Recent work suggests that the increased V̇E/V̇CO2 during exercise in mild COPD is secondary to increased deadspace (i.e. lung regions with ventilation but no perfusion) and/or ventilation/perfusion (V̇A/Q) inequality (poor matching of ventilation to perfusion). Researchers have proposed that the increased deadspace or V̇A/Q inequality is secondary to pulmonary vascular dysfunction and hypoperfusion of the pulmonary capillaries. Recently, we have shown that inhaled nitric oxide, a potent dilator of pulmonary vasculature, reduces shortness of breath and V̇E/V̇CO2, and improves exercise capacity in mild COPD. This preliminary finding suggests that pulmonary vascular dysfunction is an important contributor to exercise intolerance in mild COPD. Here, we aim to test whether sildenafil, an oral pulmonary vasodilator, can improve exercise tolerance and shortness of breath in mild COPD.

Timeline

Start

2022-03-01

Primary completion

2027-05

Completion

2027-05

Publications

• Background Blanco I, Gimeno E, Munoz PA, Pizarro S, Gistau C, Rodriguez-Roisin R, Roca J, Barbera JA. Hemodynamic and gas exchange effects of sildenafil in patients with chronic obstructive pulmonary disease and pulmonary hypertension. Am J Respir Crit Care Med. 2010 Feb 1;181(3):270-8. doi: 10.1164/rccm.200907-0988OC. Epub 2009 Oct 29.
• Background Phillips DB, Brotto AR, Ross BA, Bryan TL, Wong EYL, Meah VL, Fuhr DP, van Diepen S, Stickland MK; Canadian Respiratory Research Network. Inhaled nitric oxide improves ventilatory efficiency and exercise capacity in patients with mild COPD: A randomized-control cross-over trial. J Physiol. 2021 Mar;599(5):1665-1683. doi: 10.1113/JP280913. Epub 2021 Jan 25.
• Background Galie N, Ghofrani HA, Torbicki A, Barst RJ, Rubin LJ, Badesch D, Fleming T, Parpia T, Burgess G, Branzi A, Grimminger F, Kurzyna M, Simonneau G; Sildenafil Use in Pulmonary Arterial Hypertension (SUPER) Study Group. Sildenafil citrate therapy for pulmonary arterial hypertension. N Engl J Med. 2005 Nov 17;353(20):2148-57. doi: 10.1056/NEJMoa050010.
• Background Blanco I, Santos S, Gea J, Guell R, Torres F, Gimeno-Santos E, Rodriguez DA, Vilaro J, Gomez B, Roca J, Barbera JA. Sildenafil to improve respiratory rehabilitation outcomes in COPD: a controlled trial. Eur Respir J. 2013 Oct;42(4):982-92. doi: 10.1183/09031936.00176312. Epub 2013 Feb 21.

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