Pulmonary Artery Sling And Exercise Capacity

Abstract

INTRODUCTION: Pulmonary artery sling is a rare congenital vascular malformation that consists of an anomalous origin of the left pulmonary artery from the posterior aspect of the right pulmonary artery. The anomalous left pulmonary artery crosses the mediastinum posterior to the trachea or carina and anterior to the esophagus, compressing both organs. Respiratory complaints predominates over esophageal symptoms. In asymptomatic patients, surgical repair is controversial. Data regarding exercise capacity and other cardiopulmonary parameters is scarce. AIM: To evaluate exercise parameters in an early pubertal girl with uncorrected pulmonary artery sling at baseline and 3 years later (late puberty). METHODS: Maximal cardiopulmonary exercise testing (CPET) was completed on a cycle ergometer at age 11 y/o and 14 y/o by a girl with uncorrected pulmonary artery sling. Data was processed and analyzed retrospectively. RESULTS: Peak oxygen uptake (VO2) was higher in the first test (41.9 ml/kg/min, 119% predicted) than in the second test (30.6 ml/kg/min, 87% of predicted). Maximal and submaximal pulmonary exercise parameters improved in the second test (breathing reserve; 9.7 liters, 15% predicted in the first test vs. 31.5 liters, 39% predicted in the second test and for lowest VE/VCO2 and VE/VCO2 slope; 28.7 and 34.9 vs 25.7 and 27.7 respectively), with no similar expected improvement in cardiovascular parameters (oxygen pulse (VO2/HR) 9.2 ml/beat, 125% predicted in the first test vs. 9.3 ml/beat, 92% of predicted respectively and for VO2/HR slope; 14.1 ml/beat vs. 14.9 ml/beat). CONCLUSIONS: In this case of uncorrected pulmonary sling a deterioration in exercise capacity and cardiovascular exercise parameters was observed over puberty inspite of improvement in pulmonary parameters. Possible mechanisms are maturation dependent abnormal pulmonary sling flow, deconditioning and increased % body fat. To the best of our knowledge this is the first report of exercise evaluation in this unique population. More studies are needed with larger number of patients, including accurate measurement of body composition and characterizing exercise capacity evaluation following surgical repair.