ABSTRACT
While quadricuspid morphology is commonly observed in truncal valves, quadricuspid aortic valves (QAV) are rare and their natural history is not well described. This retrospective study of 37 patients describes the diagnostic associations and morphologic variability of QAVs in children (median age at diagnosis 4.3 y IQR 0-12 y). Associated congenital heart diseases were present in 54% (most commonly tetralogy of Fallot (TOF) and valvar pulmonary stenosis). Among patients with isolated QAV, 11 had genetic syndrome and 5 had skeletal anomalies. Valve morphology was most commonly type B (41%) and A (35%; Hurvitz and Roberts). Dilated aortic root (Z ≥ 2) was present in 5 and dilated ascending aorta in 9 patients at diagnosis. All patients with type C (n = 3) and G (n = 1) had aortic dilation. At diagnosis, >mild AR was rare (n = 1), mild regurgitation was common (n = 12, 32%), >mild AS was rare (n = 2), and mild AS was uncommon (n = 4). Over a median follow-up of 3.3y (IQR 0.9-11y), progression of AR was seen in 2 patients and progression of aortic root or ascending aorta dilation (increase in Z score by ≥ 2) was seen in 5 patients. In conclusion, QAV is a rare congenital anomaly and about half of the cases are found in hearts that are otherwise structurally normal. A relatively high prevalence is seen in patients with TOF, pulmonary stenosis, skeletal deformities, and genetic syndromes. Meticulous evaluation of aortic valve morphology should be conducted on echocardiograms performed for these indications.
ABSTRACT
BACKGROUND: The 6-minute walk test (6MWT), a simple, reliable, and valid test that uses the distance walked in 6 minute walk distance (6MWD) to quantify functional capacity, is widely used in the management of chronic disorders. However, the absence of reference standards from sub-Saharan African, including Nigerian, school-aged children limits its utility in this age group. OBJECTIVES: To develop normative values and equations for the 6MWD of school-aged Nigerian children. METHODS: In a cross-sectional study, healthy children aged 6-11 years in Lagos, Nigeria, completed the 6MWT on 20-m-long straight outdoor courses in their schools. The primary outcome was the 6MWD in meters while potential predictors included demographic (age, sex), anthropometric (height, weight, chest circumference, leg length) and physiologic variables (pre-walk, immediate post-walk, and fifth min-post-walk heart rate [HR], oxygen saturation [SpO2 ], systolic blood pressure [SBP], diastolic blood pressure [DBP], and rating of perceived exertion [RPE]; and the difference between pre-walk and post-walk HR [∆HR], SpO2 [∆SpO2 ], SBP [∆SBP], DBP [∆DBP], and RPE [∆RPE]). RESULTS: Overall, 627 pupils (52.1% girls) walked 504.6 ± 66.6 m (95% CI: 499.4, 509.8; range: 326.6-673.0 m); 16 m longer in boys (p = 0.002). A stepwise linear regression model yielded: 6MWD (m) = 347.9 + 14(Ageyears ) + 1.6 (∆HRbeats/min ) + 17.6(Sexmale=1, female=0 ) + 1.2(∆SBPmmHg ); R2 = 0.25. Previously published reference equations mostly over-estimated Nigerian children's 6MWD. CONCLUSION: These reference standards add to the global normative data on pediatric 6MWT and may be useful for the functional evaluation of Nigerian school-aged children with chronic childhood disorders.
