Endothelial function assessment-
Maternal endothelial function was assessed using the
Endo-PATTM 2000 device. Unlike previously used
techniques of duplex ultra-sonography to assess flow-mediated
vasodilation, the Endo-PATTM is totally
non-operator-dependent method, which assesses digital flow mediated
dilatation during reactive hyperemia, as a measure of endothelial
function. The device records endothelium-mediated changes in the digital
pulse waveform known as the PAT ( Peripheral Arterial Tone) signal,
measured with a pair of novel modified plethysmographic probes, situated
on the index finger of each hand. Endothelium-mediated changes in the
PAT signal are elicited by creating a downstream hyperemic response.
Hyperemia is induced by occluding blood flow through the brachial artery
for 5 minutes using an inflatable cuff on one hand. The response to
reactive hyperemia is calculated automatically by the system. Reactive
Hyperemia Index (RHI) is the post to pre occlusion PAT signal ratio in
the occluded side. These values are normalized to measurements from the
contra-lateral arm, which serves as control for non-endothelial
dependent systemic effects. Higher RHI values represent adequate
endothelial cell hyperemic response and well endothelial function. Based
on previous validation studies, RHI >1.67 was considered as
normal 1820.
All examinations were performed in the same temperature controlled room,
during the morning, after a night fasting. Figure 1 shows examples of
normal and abnormal EndoPAT tests.