This review focuses on the heart and vascular system in patients with Down syndrome. A clear knowledge on the wide spectrum of various abnormalities associated with this syndrome is essential for skillful management of cardiac problems in patients with Down syndrome. Epidemiology of congenital heart defects, cardiovascular aspects and thyroid-related cardiac impairment in patients with Down syndrome will be discussed.
AimsAn endothelin-1 receptor blocker, shown to be effective in patients with pulmonary arterial hypertension, might decrease pulmonary vascular resistance to increase cardiac filling and consequently improve exercise capacity in Fontan patients.
Methods and resultsThis was a prospective, multicentre randomized open label trial in Fontan patients. One group received bosentan for 6 months. The other group did not receive study medication for the first 3 months, followed by bosentan for 6 months. The primary endpoint was exercise capacity, and secondary endpoints were NT-proBNP level, cardiac output, SF-36 (Short Form-36) quality of life (QoL), and NYHA class. Forty-two adults (median age 29 (range 18 -56) years, 52% male, 88% NYHA class I-II) from five tertiary referral centres participated in the study. Ten patients were on diuretics. Ten patients were not motivated to finish the study. Analysis of all 32 patients who finished the study at 6 months of treatment showed that mean peak V'O 2 (24 vs. 25 mL/kg/min), median SQUASH score (6614 vs. 6390), median NT-proBNP (314 vs. 274 ng/L), and mental QoL (50 vs. 51) remained unchanged as compared with baseline (P ¼ NS, for all). After treatment, NYHA class had improved in 6 (19%), was unchanged in 24 (75%), and declined in 2 (6%) patients. Subgroup analysis on age, ventricular morphology, type of Fontan circulation, or baseline NT-proBNP level did not reveal efficacy of bosentan. Six transient adverse effects were reported.
ConclusionAn increased NT-proBNP level was present in the majority of Fontan patients. Six months of bosentan treatment was not beneficial.
Trial registration
Background The Netherlands are lacking reliable empirical data in relation to the development of birth and population prevalence of Down syndrome. For the UK and Ireland there are more historical empirical data available. A theory-based model is developed for predicting Down syndrome prevalence in the Netherlands from the 1950s onwards. It is likewise applied to Ireland and the UK for the purpose of validation. Furthermore, a prediction to 2050 is constructed. Materials and Methods Maternal age births data in the general population, maternal age related risk of Down syndrome, data on selective terminations of Down syndrome pregnancies and mortality rates (from 35 studies from the 1930s until today) were obtained to create this model. Results For the Netherlands, nowadays birth prevalence is estimated at 14 per 10 000 with around 275 total annual births. The impact of selective abortion is lower than in the UK. Present Dutch Down syndrome population prevalence is estimated, according to this theorybased model, at 7.7 per 10 000 and the grand total at 12 600 individuals. The prevalence of 'older' persons with Down syndrome (over 40 years of age) in the Netherlands will reach a peak in 2010, a doubling compared to 1990, implying an increased demand on medical care and counselling. Validity of this theory-based model was examined by comparison with relevant available empirical data from the three countries. The model shows a good fit with historical empirical research, notably four UK and two Irish population prevalence studies and eight birth prevalence studies. Conclusions A theory-based model for Down syndrome prevalence provides supplementary data in situations with a lack of empirical material and can be used for understanding and predicting long-term developments.
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