Exercise responses in aortic stenosis

Physical performance and physical activity in grown-up congenital heart disease

Aim

To review exercise performance and exercise habits in patients with congenital heart disease (CHD).

Background and methods

Physical exercise and physical activity has shown beneficial effects on the physical, psychological and social level in adult patients with cardiovascular disease. Favourable effects have also been documented in children with CHD. Exercise testing is preferentially performed on a treadmill in children, with the measurement of gas exchange.

Results

An overview of the literature showed that formal exercise testing has frequently documented reduced or suboptimal values for aerobic exercise performance in children with left-to-right shunts (atrial septal defect, ventricular septal defect), valvular heart disease and obstructive anomalies (aortic stenosis, pulmonary stenosis, coarctation of the aorta). Subnormal values for exercise tolerance have also been observed in patients with successfully repaired cyanotic heart disease (tetraology of Fallot, transposition of the great arteries, Fontan operation). An important contributing factor to the impaired exercise performance is the hypoactive lifestyle, as often observed in patients with CHD. This frequently results from parental or environmental overprotection.

Conclusion

These patients should be stimulated to be physically active, unless medical restriction is imposed. Fortunately, this represents only a small fraction of the total number of congenital heart defects for which sports participation is allowed.

Aortic stenosis: the spectrum of practice

There is significant variation in practice patterns in managing congenital aortic valve stenosis. Review of medical literature reveals no significant information regarding the current practice methods in the treatment of a simple lesion such as aortic stenosis (AS). Therefore, this survey-based study was conducted in an attempt to better understand the uniformity or heterogeneity of practice in treating AS. A questionnaire was prepared to evaluate the style of management of AS. This survey was designed to assess the practice of follow-up visitations, type and frequency of investigative studies, pharmacological therapy, and exercise recommendations. Questions about therapeutic intervention included those of timing and type of intervention. Questionnaires were sent to all academic pediatric cardiology programs in the United States (48 program) and selected international programs from Europe, Asia, and Australasia (19 program). The total number of surveys sent out was 67, and the total number of respondents was 25 (37%), 15 (31%) from the United States and 9 (53%) from outside the United States. The definition of moderate AS varied among respondents. The range provided for mild AS was identified as that with a peak-to-peak pressure gradient of < 25-30 mmHg, peak instantaneous Doppler gradient of < 36-50 mmHg, or mean Doppler gradient of < 25-40 mmHg. On the other hand, severe AS was defined as that with a peak-to-peak gradient of > 50-60 mmHg, peak instantaneous Doppler gradient of > 64-80 mmHg, or mean Doppler gradient of > 45-64 mmHg. In assessing follow-up patterns, 84% of respondents recommended seeing patients with mild AS annually, the longest time of follow-up listed in the questionnaire, whereas 20% suggested follow-up every 6 months. There was no consensus among survey centers regarding follow-up of patients with moderate AS. For severe AS, 16% recommend immediate intervention, 16% arrange follow-up every 6 months, and 56 and 28% recommend follow-up in 3 and 1 month(s), respectively. In making the decision to proceed with biventricular versus univentricular repair in patients with AS in the neonatal period, many factors were considered. Ninety-two percent of respondents rely on mitral valve z score, 84% on aortic valve z score, 52% on left ventricle length, 48% on the presence of antegrade ascending aorta flow, and only 32% considered significant endocardial fibroelastosis as a factor. Rhodes score was used by 20% of respondents in decision making regarding the approach to management of this subset of AS. This study shows that there is consensus in the management of mild and severe forms of AS. As expected, disagreement is present in the definition, evaluation, and therapy of moderate aortic valve stenosis. There is a tendency for catheter intervention except in the presence of dysplastic aortic valve or moderate to severe aortic regurgitation. There is also disagreement regarding methods used to determine biventricular versus univentricular repair of a borderline hypoplastic left heart.

Use of the heart rate monitor to modulate physical activity in adolescents with congenital aortic stenosis: an innovative approach

The task of setting exercise limitations on children with aortic stenosis is fraught with difficulties. In particular, teenagers are difficult to manage because of the increasingly professional demands of adolescents sports; the rapid changes in somatic growth, which are often accompanied by an increase in the severity of aortic valve disease; and the natural tendency of teenagers to disregard advice from authoritarian sources like a medical team. This article describes our innovative approach of using a heart-rate monitor as a means of modulating physical activity in adolescents with mild to moderate aortic stenosis. This approach enabled the setting of clear, precise, observable, measureable limits on physical activity, and self-controling of an acceptable level of physical activity. This created a different negotiation between the patient, his parents, and the medical team, and eased the concern and anxiety of the mothers.