Vascular assessments

Ankle and toe brachial index:

• The Ankle Brachial Index (ABI) is the systolic pressure at the ankle, divided by the systolic pressure at the arm. It has been shown to be a specific and sensitive metric for the diagnosis of peripheral artery disease (PAD). Additionally, the ABI has been shown to predict mortality and adverse cardiovascular events independent of traditional CV risk factors.
• Toe brachial index (TBI) and is a calculation based on the systolic blood pressures of the arm and the systolic blood pressures of the toes, and is typically used when the ABI cannot be accurately assessed.
• The SoNLCP houses a Summit Doppler Vista ABI L450VA Vascular System – the Vista ABI, located in the SoNLCP, is a full-featured ABI System designed to make the ABI exam faster and easier to conduct, interpret, and document. It includes 2 modalities: PVR and an 8 MHz bi-directional vascular doppler probe. Other features include automated cuff inflation and deflation, built-in printer, graphic waveform display with step-by-step ABI instructions, and 4 blood pressure cuffs. The Vista ABI has the capacity to measure both ABI and TBI.

Venous Occlusion Plethysmography

A Hokanson plethsymograph using air-filled cuffs is used to measure limb blood flow at rest and immediately following isotonic exercise or a 5 minute transient ischemia. Venous occlusion plethysmography is a simple yet powerful technique for the non-invasive measurement of limb (arm or leg) blood flow. It has been used extensively in both the experimental and clinical settings. The underlying rationale is that when venous outflow from an extremity is occluded, any immediate increase in volume of this compartment must originate from the on-going arterial inflow. Mercury-in-silastic strain gauges are typically used to measure these volume changes, the rates of which are directly proportional to blood flow.

Endothelial Function with EndoPAT

The EndoPAT is an innovative, safe and non-invasive diagnostic device for Functional Vascular Health Assessment for both large and small arteries. It is an FDA cleared non-invasive test to evaluate the level of endothelial function. Endothelial dysfunction is recognized by the medical community as the critical junction between risk factors and clinical disease. It is the earliest detectable stage of cardiovascular disease. The test is uniquely performed at the fingertip and proven to be accurate, sensitive and reproducible. The EndoPAT quantifies the endothelium-mediated changes in vascular tone, elicited by a 5-minute occlusion of the brachial artery (using the standard blood pressure cuff). When the cuff is released, the surge of blood flow causes an endothelium-dependent flow mediated dilatation (FMD). The dilatation, manifested as reactive hyperemia, is captured by EndoPAT as an increase in the PAT Signal amplitude. A post-occlusion to pre-occlusion ratio is calculated by the EndoPAT™ software, providing the EndoPAT index.

Pulse Wave Recording (PVR):

Pressurized cuffs (similar to blood pressure cuffs) are place on the legs and then connected to a machine called a pulse volume recorder. Usually, one or two cuffs are placed around the thigh, another on the upper calf, and one just above the ankle. An additional cuff above the elbow provides an idea of blood flow in a healthy limb. The cuffs are inflated and continuously monitor the arteries as the blood pulses through them. The recording machine converts these measurements into a waveform (a continuous line of peaks and valleys) that represents the movement of blood through the arteries.

Pulse wave analysis with Complior from ALAM Medical:

Pulse wave velocity (PWV) is the velocity at which the arterial pulse propagates through the circulatory system. PWV is used clinically as a measure of arterial stiffness. It is easy to measure invasively and non-invasively in humans, is highly reproducible, has a strong correlation with cardiovascular events and all-cause mortality, and was recognized by the European Society of Hypertension as an indicator of target organ damage and a useful additional test in the investigation of hypertension. A high pulse wave velocity (PWV) has also been associated with poor lung function