Vascular Testing

Echocardiograms  |  Doppler  |  ABI
Vascular studies are tests that check the blood flow in your arteries and veins. These tests are noninvasive. This means they don’t use any needles. They use high-frequency sound waves (ultrasound) to measure the amount of blood flow in your blood vessels. A small handheld probe (transducer) is pressed against your skin. The sound waves move through your skin and other body tissues to the blood vessels. The sound waves echo off of the blood cells. These echoes are then sent to a computer and seen on a screen as images or video.

Echocardiograms

An echocardiogram, often referred to as a cardiac echo or simply an echo, is a sonogram of the heart. Echocardiography uses standard two-dimensional, three-dimensional, and Doppler ultrasound to create images of the heart. It has become routinely used in the diagnosis, management, and follow-up of patients with any suspected or known heart diseases. It is one of the most widely used diagnostic tests in cardiology. It can provide a wealth of helpful information, including the size and shape of the heart (internal chamber size quantification), pumping capacity, and the location and extent of any tissue damage. An echocardiogram can also give physicians other estimates of heart function, such as a calculation of the cardiac output, ejection fraction, and diastolic function (how well the heart relaxes). Echocardiography can help detect cardiomyopathies, such as hypertrophic cardiomyopathy, dilated cardiomyopathy, and many others. The use of stress echocardiography may also help determine whether any chest pain or associated symptoms are related to heart disease. The biggest advantage to echocardiography is that it is not invasive (does not involve breaking the skin or entering body cavities) and has no known risks or side effects.

Doppler

Doppler ultrasonography is medical ultrasonography that employs the Doppler effect to generate imaging of the movement of tissues and body fluids (usually blood), and their relative velocity to the probe. By calculating the frequency shift of a particular sample volume, for example flow in an artery or a jet of blood flow over a heart valve, its speed and direction can be determined and visualized. Color Doppler or color flow Doppler is the presentation of the velocity by color scale. Color Doppler images are generally combined with grayscale (B-mode) images to display duplex ultrasonography images, allowing for simultaneous visualization of the anatomy of the area. This is particularly useful in cardiovascular studies (sonography of the vascular system and heart) and essential in many areas such as determining reverse blood flow in the liver vasculature in portal hypertension.

ABI

The ankle-brachial pressure index (ABPI) or ankle-brachial index (ABI) is the ratio of the blood pressure at the ankle to the blood pressure in the upper arm (brachium). Compared to the arm, lower blood pressure in the leg suggests blocked arteries due to peripheral artery disease (PAD). The ABPI is calculated by dividing the systolic blood pressure at the ankle by the systolic blood pressure in the arm.

A Doppler ultrasound blood flow detector, commonly called Doppler wand or Doppler probe, and a sphygmomanometer (blood pressure cuff) are usually needed. The blood pressure cuff is inflated proximal to the artery in question. Measured by the Doppler wand, the inflation continues until the pulse in the artery ceases. The blood pressure cuff is then slowly deflated. When the artery’s pulse is re-detected through the Doppler probe the pressure in the cuff at that moment indicates the systolic pressure of that artery.

The ABPI test is a popular tool for the non-invasive assessment of PVD. Studies have shown the sensitivity of ABPI is 90% with a corresponding 98% specificity for detecting hemodynamically significant (Serious) stenosis >50% in major leg arteries, defined by angiogram.

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