This study is a multi-institutional prospective cohort study from 6 centers enrolling 20 patients > 10 yrs. of age with at least a 10% difference in normal pulmonary blood flow distribution between lungs.

All patients underwent pre-procedural CPET, echocardiography or MRI, perfusion scans (or MRI), and a chronic dyspnea score. All patients underwent CPET, perfusion scan, or MRI (to assess differential flow) and chronic dyspnea scoring post-intervention.

All patients had technically successful procedures with > 50% increase in angiographic luminal diameter. Physiologic success (> 20% improvement in flow to stenosed lung) was achieved in 10/15 pts in whom post-procedural perfusion imaging was performed.

Before the intervention, all patients had decreased exercise capacity and abnormally high VE/VCO2. There was an improvement in percent predicted peak VO2, percent predicted O2 pulse, and the slope of VE/VCO2 post-intervention. Chronic dyspnea score also improved post-intervention significantly. Intervention on unilateral branch pulmonary artery stenosis results in high technical success and physiologic and clinical improvements in most patients.

All interventional cardiologists should be aware of these results. This study should stimulate further research into the physiologic effects of unilateral branch pulmonary artery interventions in a larger cohort of patients.

All editors: David Balzer, MD, FSCAI