The Identification and Impact of Abnormal Spirometry Patterns on Exercise Capacity in Pediatric Patients with Fontan...

Reduced exercise capacity and restrictive lung physiology are common in patients after Fontan palliation (FP). However, there is paucity of data regarding the association between specific spirometry patterns and key exercise parameters in this population. This is a single-center, cross-sectional, study correlating pulmonary function and exercise parameters in children with FP. Patients who were ≤ 18 years of age and underwent a comprehensive cardiopulmonary treadmill exercise stress test (CPT) and spirometry at the same time, were included. Patients were categorized as (i) normal or (ii) abnormal based on the results of spirometry. The abnormal group was subdivided into (a) restrictive, (b) obstructive, and (c) mixed patterns. Demographic and key exercise parameters were compared between groups. Our study included 82 patients who underwent CPT at 13.6 (IQR, 11.3-15.4) years of age. A reduced exercise capacity (%VO₂ ≤ 85%) was noted in the majority (n = 50, 61%). Spirometry was abnormal in 47 (57%) patients [restrictive (n = 25, 30%), obstructive (n = 12, 15%), and mixed (n = 10, 12%)]. The abnormal spirometry group had significant lower %VO₂ (77% vs. 92%, p = 0.01) and METS (8.4 vs. 9.6, p = 0.02). Subgroup analysis revealed that obstructive (p = 0.04) and mixed (p = 0.02) patterns were associated with a significant decrease in % VO₂. Majority of the children demonstrated an abnormal spirometry pattern post-FP. Abnormal pulmonary function was associated with the reduced exercise capacity. Identification and treatment of the abnormal lung function may improve the exercise capacity in these patients and improve the morbidity.