Balloon Angioplasty and Stenting for Unilateral Branch Pulmonary Artery Stenosis Improve Exertional Performance

Objectives: This study sought to determine whether pulmonary artery intervention in patients with unilateral proximal pulmonary artery stenosis (PAS) improves exercise capacity, abnormal ventilatory response to exercise, and symptoms. Background: Stenosis of the branch pulmonary arteries results in pulmonary blood flow maldistribution (PBFM). The resulting ventilation–perfusion mismatch is associated with an increased ventilatory response to exercise and decreased exercise capacity. It is unclear if technical success in relieving branch PAS translates to clinical improvement in exercise capacity and ventilatory response. Methods: Twenty patients with biventricular circulation and a minimum 10% PBFM who underwent transcatheter relief of PAS were enrolled in a multi-institutional prospective cohort study. Pre- and post-procedure assessment of the degree of PBFM, exercise capacity, ventilatory response to exercise, and subjective assessment of breathlessness were collected and analyzed. Results: Technical success was achieved in all patients with significant angiographic improvement in minimal lumen diameter (p = 0.001) and peak gradient (p = 0.001). Median PBFM improved (19.5% [range 12.0% to 31.0%] before vs. 7.0% [range 0% to 33.0%] after; p = 0.003). Exercise capacity was low at baseline and improved significantly post-intervention; percent predicted peak oxygen consumption improved from 70% (range 45% to 96%) to 83% (range 47% to 121%) (p = 0.02). Percent predicted oxygen pulse improved (p = 0.02). Ventilatory response to exercise improved; ventilatory equivalent of carbon dioxide slope post-intervention decreased to 29.3 versus 32.5 pre-intervention (p = 0.01). Subjective assessment of dyspnea improved. Five patients with minimal improvement in PBFM also showed minimal improvement in exercise parameters. Conclusions: Successful relief of unilateral branch PAS results in significant improvements in exercise capacity, ventilatory efficiency, and symptoms.