Can 10 000 Healthy Steps a Day Slow Aortic Root Dilation in Pediatric Patients with Marfan Syndrome?

Background Stiffer aortas are associated with a faster rate of aortic root (AoR) dilation and higher risk of aortic dissection in patients with Marfan syndrome. We have previously shown that mild aerobic exercise reduces aortic stiffness and rate of AoR dilation in a Marfan mouse model. In this study, we investigated if these results could be translated to pediatric patients with Marfan syndrome. Methods and Results We enrolled 24 patients with Marfan syndrome aged 8 to 19 years to participate in a 6‐month physical activity intervention, excluding those with ventricular dysfunction or prior history of aortic surgery. We instructed patients to take 10 000 steps per day, tracked by an activity tracker. At baseline and 6 months, we measured AoR dimension, arterial stiffness, endothelial function, physical activity indices, inflammatory biomarkers, and coping scores. Controls consisted of 15 age‐matched patients with Marfan syndrome. Twenty‐four patients with Marfan syndrome (median age, 14.4 years [interquartile range {IQR}, 12.2–16.8], 14 male patients) were enrolled. Baseline assessment demonstrated that the majority of these patients were sedentary and had abnormal arterial health. Twenty‐two patients completed the intervention and took an average of 7709±2177 steps per day (median, 7627 [IQR, 6344–9671]). Patients wore their Garmin trackers at a median of 92.8% (IQR, 84%–97%) of their intervention days. AoR Z score in the intervention group had a significantly lower rate of change per year compared with the controls (rate of change, −0.24 versus +0.008; P=0.01). Conclusions In this clinical intervention in pediatric patients with Marfan syndrome, we demonstrated that a simple physical activity intervention was feasible in this population and has the potential to decrease the AoR dilation rate. REGISTRATION URL: https://www.clinicaltrials.gov; Unique identifier: NCT03567460.