ABC | Volume 110, Nº6, June 2018

Original Article Marui et al Blood pressure variables in Duchenne muscular dystrophy Arq Bras Cardiol. 2018; 110(6):551-557 Table 1 – Classification of blood pressure (BP) levels in children Classification Office BP Mean SBP and DBP on ABPM Blood pressure loads (SBP and DBP) Normal BP < 90 th percentile < 95 th percentile < 25% White coat hypertension ≥ 95 th percentile < 95 th percentile < 25% Prehypertension ≥ 90 th percentile or > 120/80 mm Hg < 95 th percentile ≥ 25% Masked hypertension < 95 th percentile > 95 th percentile ≥ 25% Ambulatory hypertension > 95 th percentile > 95 th percentile 25-50% Severe ambulatory hypertension > 95 th percentile > 95 th percentile > 50% Adapted from: A Scientific Statement From the American Heart Association. Hypertension. 15 SPB: systolic blood pressure; DBP: diastolic blood pressure; ABPM: ambulatory blood pressure monitoring. Table 2 – Baseline characteristics of the patients Age groups 3 - 5 years, n (%) 3 (6.5) 6 - 8 years, n (%) 15 (32.6) 9 - 11 years, n (%) 18 (39.1) 12 - 14 years, n (%) 7 (15.2) 15 - 17 years, n (%) 3 (6.5) Clinical characteristics Previous diagnosis of SAH,* n (%) 3 (6.5) Other family members with DMD † 3 (6.5) Use of bipap ‡ 6 (13) Use of AMBU 12 (26) Wheelchair-bound 26 (56.5) Motor physical therapy 29 (63) Use of corticosteroid 32 (69.6) Age of the first symptoms of DMD, md (IQR) 7 (5-8) Age of diagnosis of DMD, md (IQR) 2.5 (1.2-4.5) SAH*: systemic arterial hypertension; DMD † : Duchenne muscular dystrophy; bipap ‡ : Bilevel PositiveAirway Pressure. Data expressed as numbers (n) and percentages (%); age in median (md) and interquartile range (IQR). ND was present in 29.9% of the children with DMD. More than half of the participants (53.1%) had attenuated ND, while 15% had reverse ND. The age groups of 9-11 years and 6-8 years concentrated the highest percentage of ND attenuation, 19.1% and 14.9% respectively. Regarding DBP, ND was present in 53.2% of the boys; 27.7% had extreme ND (highest percentage in the age group of 6-11 years: 19.1%), while 14.9% had attenuated ND. For BP stratification, the BPmeasurements taken at the office and on ABPMwere considered. Although the recommendations of the specialized guidelines suggest classifying BP in one of the ABPM periods (wakefulness or sleep) or in 24 hours, we classified BP in all periods (Table 4). Regarding the use of corticosteroids, there was no association between corticosteroid use and BP classification in 24 hours (p = 0.904), during wakefulness (p = 0.720) and sleep (p = 0.996). Discussion Duchenne muscular dystrophy is a disease of poor prognosis, whose survival extends to the second decade of life. 20 However, the advances in treatment, such as non‑invasive ventilation and physical therapy, have enabled boys with DMD to reach 30 years of age. Considering this increase in life expectancy, other aspects, in addition to neuromuscular impairment, need to be assessed. 20 Although office BP classification in pediatrics was standardized by the National High Blood Pressure Education Program in 2004, the classification of BP obtained from ABPM in children and adolescents has not been standardized. Thus, we used the recommendations based on expert opinions, such as those published by the AHA in 2008. Blood pressure classification in children, according to those recommendations, should consider, in addition to measurements taken at the office, those from ABPM during 24 hours, wakefulness or sleep, and SBPL or DBPL. 21,22 A study on the BP of boys with DMD has reported the prevalence and correlations of low BP levels measured at the office with a possible autonomic dysfunction due to DMD. 23 Regarding office BP measurement, more than 50% of the boys had stage 1 or 2 AH, and 12.8% had borderline BP levels. The VII Brazilian Guidelines on Hypertension replaced the term ‘borderline’ with ‘prehypertension’, and estimates its prevalence between 10% and 15% of the pediatric population. However, established AH affects 3% to 5% of the children. 24 In our study, the highest SBP mean during wakefulness was 126.7 ± 10.0 in the age group of 12-14 years, followed by 122 ± 18.6 for office BP in children aged 6-8 years. Considering the percentile for age, the BP mean on ABPM during wakefulness was within the expected range. However, the BP mean at the office was above the 95th percentile. Regarding DBP, the highest mean was observed in the 95 th percentile (78.5 ± 12.4) in the age group of 6-8 years on ABPM during wakefulness, followed by 77.3 ± 9.1 in the age group of 15-17 years on ABPM, which is above the estimated percentile. Regarding SBPL and DBPL, all age groups had median > 25% in 24 hours, wakefulness or sleep. Considering only wakefulness, 38.3% of the children had normal BP, 21.3% had severe AH, and 21.3% had white coat hypertension. 553