Role of the Baroreflex in Long-Term Blood Pressure Regulation in Children Born With Very Low Birth Weight

<bold>INTRODUCTION:</bold> Children born preterm and with very low birth weight are at increased risk of developing elevated blood pressure (BP) later in life. One mechanism of short-term BP regulation is the baroreflex, which can be assessed by calculating baroreflex sensitivity (BRS). There is evidence in animals that the baroreflex may play a role in regulating BP on a long-term basis, but evidence is lacking in humans, particularly children. <bold>PURPOSE:</bold> To examine relationships between short-term measures of baroreflex function (i.e. BRS) and long-term ambulatory BP and variability in a cohort of children born with very low birth weight. <bold>METHODS:</bold> Spontaneous BRS was measured during 10 minutes of supine rest using a Continuous Non-Invasive Arterial Pressure (CNAP) Monitor 500. Nevrokard software calculated BRS using the sequence method (BRSseq) and spectral method (LF&alpha;). Ambulatory BP monitoring took place over a 24-hour period. Data were analyzed separately for awake and asleep periods. Variability was calculated as standard deviations (SD) for awake and asleep and a weighted SD for the 24-hour period. Relationships between measures of BRS and ambulatory BP were examined using correlational analysis. <bold>RESULTS:</bold> A total of 33 participants (22 female, 11 male) had both BRS and ambulatory BP data. Mean BRS values were 24.2 ± 20.4 ms*mmHg-1 for BRSseq and 23.3 ± 12.7 ms*mmHg-1 for LF&alpha;. Mean absolute ambulatory SBP/DBP for the 24-hour period was 115.4/66.9. Mean ambulatory BP variability was 9.1 ± 17 mmHg for the 24-hour period. Negative correlations were found between BRSseq and both 24-hour SBP (r=-.336, p=.087) and asleep SBP (r=-.370, p=.053). There were no significant relationships between BRS and ambulatory BP variability. <bold>CONCLUSION:</bold> The results revealed that BRS accounted for 11-14% of the shared variance in ambulatory SBP suggesting that the baroreflex likely plays at least a partial role in regulating BP on a long-term basis in preterm, VLBW adolescents who are at risk for developing hypertension.

Grantor dc:publisher

Wake Forest University

Year dc:date.issued

2012

Author dc:creator

• Mazanka, Paul James

• baroreceptors

Language dc:language.iso

en

Handle dc:identifier.uri

http://hdl.handle.net/10339/37301

OAI identifier oai:identifier

oai:wakespace.lib.wfu.edu:10339/37301