Does Mitral Stenosis Impact Exercise Capacity in Children with Mild to Moderate Aortic Stenosis?

Abstract

PURPOSE: Mild to moderate aortic stenosis does not typically impact exercise capacity in children. The purpose of this study was to determine the impact of mitral stenosis (MS) on exercise capacity in patients with mild to moderate aortic stenosis (AS). METHODS: Isolated mild to moderate AS patients and combined MS/AS patients underwent maximal exercise echocardiography using the James protocol. Subjects with structurally normal hearts (Norm) served as controls. Baseline and peak exercise data and echo valvar gradients were compared using one-way ANOVA and the Bonferroni t procedure. RESULTS: 13 studies in 10 patients with isolated AS (mean age 15.3 years) were compared to 13 studies in 8 patients with combined MS/AS (mean age 14.6 yrs) and 26 normal subjects (mean age 14.2 yrs). Demographics, total working capacity (TWC), maximal systolic blood pressure (SBP) and respiratory quotient (MaxRQ) were not significantly different among the groups. There was no significant change in mean aortic gradient from rest to peak exercise in MS/AS and AS groups (19±11 to 29±9, 25±11 to 24±15mmHg). There was a significant increase in mean mitral gradient from rest to peak exercise in the MS/AS group (5±2 to 16±8 mmHg, p<0.001). The MS/AS group demonstrated a significantly decreased MaxHR compared to Norm and significantly decreased maximal oxygen consumption (MVO2) and cardiac output (MaxQ) compared to both AS and Norm groups.TableCONCLUSION: In pediatric patients with mild to moderate aortic stenosis, the presence of mild mitral stenosis negatively impacts aerobic capacity and cardiac output at peak exercise. This suggests the possibility that mitral stenosis perturbs the adaptive mechanisms utilized by these subjects during peak exercise.