Exercise function of children with congenital aortic stenosis following aortic valvuloplasty during early infancy.

OBJECTIVES

The objectives of this study were to characterize the exercise function of patients treated with balloon aortic valvuloplasty at <or=6 months of age, and identify factors associated with exercise dysfunction.

BACKGROUND

Balloon aortic valvuloplasty is the primary therapy for neonatal aortic stenosis (AS). Residual and/or acquired abnormalities of left heart structure and function may adversely affect exercise capacity. Methods. We prospectively recruited patients >6 years old with a history of neonatal AS to undergo exercise testing.

RESULTS

We enrolled 30 patients (median age 13.1 years) who underwent balloon aortic valvuloplasty at a median age of 12 days. At time of exercise testing, the median maximum Doppler AS gradient was 34 mm Hg (0-70 mm Hg); 11 patients had moderate or severe aortic regurgitation. All patients were asymptomatic. Overall, peak oxygen consumption (VO(2)) was below normal (87 +/- 18% predicted; P < .001), and was severely depressed (<or=70% predicted) in 7 patients (23%). Although peak O(2) pulse was well preserved overall (97 +/- 22% predicted; P= .36), 11 patients had an O(2) pulse <85% predicted, including all patients with VO(2)<or= 70% predicted. Peak heart rate was below normal overall (91 +/- 7% predicted, P < .001), but severe chronotropic dysfunction (<or=70% predicted) was rare (n = 1). Age at testing correlated inversely with peak VO(2) (R(2)= 0.30; P= .002). No other demographic, historical, or echocardiographic variables were associated with peak VO(2).

CONCLUSION

Although exercise function is preserved in most patients with a history of AS treated in early infancy, a subset have markedly reduced peak VO(2), usually because of inability to increase stroke volume.