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.