To determine whether altered baroreceptor function may contribute to systemic hypertension after coarctation of the aorta (C of A) repair, baroreceptor function was evaluated in 6 children with repaired C of A mild arm systolic hypertension. Data were compared with those from 7 normotensive control children with hemodynamically mild heart disease. Age at C of A repair averaged 9.9 ± 3.1 years (mean ± standard deviation [SD]). Arm systolic pressure was 143.8 ± 2.9 mm Hg in the C of A repair group, compared with 118.3 ± 9.9 for control subjects (p < 0.001). At catheterization, steady-state sigmoidal baroreceptor function curves relating mean arterial pressure to R-R interval were derived by increasing and decreasing mean arterial pressure with small injections of phenylephrine and nitroprusside. Compared with control subjects, the baroreceptor function curves of children with repaired C of A (1) are reset about a higher baseline mean arterial pressure (108.8 ± 6.6 versus 90.3 ± 8.6 mm Hg, p < 0.01), (2) have a decreased slope (7.9 ± 3.7 versus 17.4 ± 3.6 ms/mm Hg, p < 0.001), and (3) have a diminished R-R interval range (246.7 ± 81.5 versus 535.7 ± 97.2 ms, p < 0.001). Thus, in children with hypertension after C of A repair, the baroreflex is reset to an elevated mean arterial pressure level and has a diminished sensitivity to changes in arterial pressure.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine