Assessing Endothelial Vasodilator Function with the Endo-PAT 2000

Abstract

The endothelium is a delicate monolayer of cells that lines all blood vessels, and which comprises the systemic and lymphatic capillaries. By virtue of the panoply of paracrine factors that it secretes, the endothelium regulates the contractile and proliferative state of the underlying vascular smooth muscle, as well as the interaction of the vessel wall with circulating blood elements. Because of its central role in mediating vessel tone and growth, its position as gateway to circulating immune cells, and its local regulation of hemostasis and coagulation, the the properly functioning endothelium is the key to cardiovascular health. Conversely, the earliest disorder in most vascular diseases is endothelial dysfunction.In the arterial circulation, the healthy endothelium generally exerts a vasodilator influence on the vascular smooth muscle. There are a number of methods to assess endothelial vasodilator function. The Endo-PAT 2000 is a new device that is used to assess endothelial vasodilator function in a rapid and non-invasive fashion. Unlike the commonly used technique of duplex ultra-sonography to assess flow-mediated vasodilation, it is totally non-operator-dependent, and the equipment is an order of magnitude less expensive. 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 finger index 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. A PAT ratio is created using the post and pre occlusion values. These values are normalized to measurements from the contra-lateral arm, which serves as control for non-endothelial dependent systemic effects. Most notably, this normalization controls for fluctuations in sympathetic nerve outflow that may induce changes in peripheral arterial tone that are superimposed on the hyperemic response.

Association of Subjective and Objective Sleep Duration as well as Sleep Quality with Non-Invasive Markers of Sub-Clinical Cardiovascular Disease (CVD): A Systematic Review

“…The volume changes in the fingertip are documented digitally as pulse amplitude that can be tracked over time. The expected response is a post occlusion increase of the PAT signal amplitude and the PAT score is provided automatically by the system's software and is basically the ratio between the post- to pre-occlusion average signal size, corrected for systemic changes and baseline level 26) . Iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP) is a tool used to determine microvascular endothelial function.…”

Effect of chokeberry juice consumption on antioxidant capacity, lipids profile and endothelial function in healthy people: a pilot study

“…According to the specification of the device, the correct RHI index is above 1.67. This method is simple, fast and non-invasive, having a recommendation for such determinations (Axtell et al 2010;Moerland et al 2012).…”

A Single Session of Neuromuscular Electrical Stimulation Enhances Vascular Endothelial Function and Peripheral Blood Circulation in Patients With Acute Myocardial Infarction

“…Primary outcome measure: The reactive hyperemia peripheral arterial tonometry (RH-PAT) index was measured in the supine position using Endo-PAT 2000 (Itamar Medical, Caesarea, Israel) as a parameter of vascular endothelial function, as described previously. 11,12) A blood pressure cuff was placed on one of the patient's upper arms with the contralateral arm serving as the control. Fingertip probes were placed on the index fingers of both hands to measure the arterial pulse wave amplitude.…”