Abstract 2994: Gender-Related Differences in the Central Arterial Pressure Waveform Begin in Childhood and are Independent of Height

Abstract

Introduction Women develop age-related LV hypertrophy and symptomatic heart failure to a greater extent than men. Contributing to this may be a higher pulsatile afterload in women, with a higher central arterial systolic augmentation pressure (AP, peak pressure minus pressure at systolic shoulder) and augmentation index (AIx, ratio of AP to pulse pressure). It is unclear if these differences are due to gender per se or shorter female stature. We studied 8-year old children to determine if gender-related differences in carotid pressure augmentation are present in early life and if so, whether they are independent of height (Ht). Methods 406 children (age 8.0 ± 0.1, 49% girls) had anthropometry, brachial systolic and diastolic BP (SBP, DBP), heart rate (HR) and carotid and radial pressure waveforms (by applanation tonometry, calibrated to mean BP and DBP) assessed. Carotid ultrasound evaluated arterial elasticity [Carotid Artery Compliance (CAC), Stiffness Index (SI) and Young’s Elastic Modulus (YEM)]. Results Boys and girls had a similar Ht (129 ± 6 v 128 ± 6 cm), BMI (17.6 ± 3.1 v 17.5 ± 3.0), SBP (100 ± 7 v 101 ± 5 mmHg), DBP (59 ± 6 v 60 ± 5 mmHg) and HR (80 ± 10 v 82 ± 10 bpm). The carotid AP and AIx were significantly higher in girls (−4 ± 3 v −6 ± 4 mmHg and −12 ± 8 v −16 ± 9 respectively, p < 0.001), indicating greater systolic pressure augmentation. Time to onset of the reflected wave ( Tr ) and time to peak of the reflected wave were shorter in girls (154 ± 19 v 163 ± 18 msec, p < 0.001 and 206 ± 23 v 212 ± 22 msec, p = 0.03 respectively), indicating earlier wave reflection. Girls had a higher velocity index (Vr) estimated from Ht ( Vr = Ht /Tr , 8.4 ± 1.0 v 8.0 ± 0.9 m/sec, p = 0.001). Ejection duration, maximum rate of pressure rise and time to systolic peak (indicating effect of ventricular ejection on the carotid waveform) were not significantly different between genders. Boys, however, had stiffer carotid arteries than girls [lower CAC (5.8 ± 1.5 v 6.2 ± 1.8 %/10 mmHg, p = 0.016), higher SI (2.7 ± 0.7 v 2.5 ± 0.7, p = 0.012) and YEM (735 ± 217 v 681 ± 237, p = 0.021)]. Conclusion Even in the first decade of life, girls demonstrate greater central arterial pressure augmentation than boys, with earlier wave reflection. This is independent of height and may contribute to cardiovascular morbidity in females, later in life.