Normalization of Autonomic Function in Children With Coarctation of the Aorta After Surgical Correction in Infancy

Postnatal Cardiac Autonomic Nervous Control in Pediatric Congenital Heart Disease

Congenital heart disease is the most common congenital defect. During childhood, survival is generally good but, in adulthood, late complications are not uncommon. Abnormal autonomic control in children with congenital heart disease may contribute considerably to the pathophysiology of these long term sequelae. This narrative review of 34 studies aims to summarize current knowledge on function of the autonomic nervous system in children with a congenital heart defect. Large scale studies that measure both branches of the nervous system for prolonged periods of time in well-defined patient cohorts in various phases of childhood and adolescence are currently lacking. Pending such studies, there is not yet a good grasp on the extent and direction of sympathetic and parasympathetic autonomic function in pediatric congenital heart disease. Longitudinal studies in homogenous patient groups linking autonomic nervous system function and clinical outcome are warranted.

Through the glass darkly: searching for safety signals in physiological monitoring

Perioperative monitoring of ventilation, gas exchange, heart rate, blood pressure, and other basic physiological measures give important information on the well-being of the child in the perioperative period. However, despite this level of surveillance, perioperative events that appear to be unheralded still occur. Improvements in alarms and alarm design combined with integrated analysis of monitored parameters that map to adverse outcomes may provide earlier warning of potential danger. Near real-time analysis of heart rate and blood pressure variability can provide information on autonomic function and cardiac reserve, while devices such as tissue oximetry may be beneficial to optimize regional and global blood flow.

Vascular and autonomic function in preschool-aged children with congenital heart disease

OBJECTIVE

To compare indices of vascular health and heart rate variability in preschool-aged children with repaired congenital heart disease (CHD) including tetralogy of Fallot (n = 6) and coarctation of the aorta (n = 6).

DESIGN

  A cross-sectional study design was used. All measures were noninvasive and collected over a single testing session under the supervision of a parent/guardian.

SETTING

  Data collection took place in a quiet, temperature-controlled room (23°± 1°C) with the participant in a supine position.

PATIENTS

  Twelve (six females, six males) preschool-aged children with repaired CHD (CHD: 4 ± 1 years) and 12 age- and gender-matched healthy controls (CON: 5 ± 1 years) participated in the study.

OUTCOME MEASURES

  Supine, resting measures of heart rate variability (time, frequency, and nonlinear domains), whole-body pulse wave velocity (ventricular depolarization to dorsalis pedis artery), brachial blood pressures, and carotid artery distensibility, lumen diameter, intima-media thickness, and wall/lumen ratio were collected in both groups.

RESULTS

  The groups were similar in age, height, and weight; however, CON had significantly higher body mass index values (CON: 16.9 ± 2.2, CHD: 15.1 ± 1.0, P < .05) and body mass index percentiles (CON: 69 ± 27%tile, CHD: 36 ± 24%tile, P < .01) compared to CHD. No group differences were found for resting brachial blood pressures, whole-body pulse wave velocity, heart rate variability, and carotid artery distensibility, lumen diameter, and intima-media thickness (P > .05). Carotid artery pulse pressures (CHD: 38 ± 6 mm Hg, CON: 31 ± 6 mm Hg, P < .05) and wall/lumen ratios (CHD: 0.091 ± 0.007, CON: 0.085 ± 0.006, P < .01) were significantly higher in the CHD group.

CONCLUSIONS

  These results may indicate that preschool-aged children with repaired CHD display early signs of vascular remodeling, but not autonomic or vascular dysfunction. The effects of larger wall/lumen ratios on cardiovascular disease risk require further investigation.

Relationship of aortic pulse wave velocity and baroreceptor reflex sensitivity to blood pressure control in patients with repaired coarctation of the aorta

BACKGROUND

Increased aortic stiffness and reduced baroreceptor reflex sensitivity have been described independently after coarctation of the aorta (CoA) repair. This study sought to determine the relationship between these variables and blood pressure control in adolescents after early CoA repair.

METHODS

Spontaneous baroreceptor reflex sensitivity (sBRS) and aortic pulse wave velocity (PWV) were measured in 29 adolescents after CoA repair and compared with 20 age-matched controls. Patients treated for hypertension or having residual aortic narrowing were excluded. Ambulatory blood pressure (ABP), heart rate variability, and cardiac output were also recorded. After ABP measurement, CoA subjects were classified as normotensive or hypertensive.

RESULTS

Nine patients (31%) were hypertensive according to standard definitions, and this subgroup had higher aortic PWV than the normotensive subgroup (P = .004). There was a significant positive correlation between ABP and PWV seen in the whole CoA group (r(2) = 0.5, P < .01). The normotensive subgroup had increased sBRS compared with controls (P = .02). This difference was not seen between the hypertensive subgroup and controls. There was a significant inverse relationship between sBRS and aortic PWV in the whole CoA group (r(2) = 0.25, P = .01). The normotensive subgroup had a significant reduction in stroke index compared with controls (P = .02), which was not seen in the hypertensive subgroup (P = .96).

CONCLUSIONS

Adolescents with hypertension after CoA repair have increased aortic PWV and a relative reduction in sBRS compared with normotensive CoA patients. Thus, failure of the baroreceptor reflex to compensate for increasing arterial stiffness may herald the onset of hypertension in these patients.

Hypertension and coarctation of the aorta: an inevitable consequence of developmental pathophysiology

Patients with coarctation of the aorta develop early onset hypertension in spite of early effective repair. This is associated with significant morbidity and is arguably the single most important outcome variable in this patient group. We discuss the potential pathophysiological mechanisms involved in the development of hypertension with clinical reference to monozygotic twins, and review potential strategies for therapy and prevention in this setting.