Assessment of central arterial pressure

Healthy lifestyle and dietary choices, as well as medications, can treat and even reverse damage done to your endothelium. This includes getting more exercise, eating healthier foods, quitting smoking, taking cholesterol lowering drugs, and blood pressure medications, to name a few.

When the endothelium does not work as it should, blood vessels can become inflamed, which leads to atherosclerosis, or the build-up of plaque inside your blood vessels, commonly known as “hardening of the arteries.” This can lead to problems with the blood vessels supplying the heart and brain with oxygen, which can result in a heart attack or stroke.

A number of risk factors greatly increase your chance of endothelial damage, including physical inactivity, poor diet, tobacco smoking, high cholesterol, high blood pressure, aging, and diabetes.

Loss of normal endothelial function is a sign of cardiovascular disease (CVD). It is considered an important early event in the development of atherosclerosis, which involves the thickening of your arterial walls as a result of the build-up of calcium and fatty materials.

The endothelium is the single-cell-thick interior lining of all the blood vessels in your body. Endothelial cells play key roles in regulating blood flow and the passage of materials and white blood cells into and out of the bloodstream.

The TBI is calculated by dividing ankle blood pressure by arm blood pressure. The formula is: TBI = Ankle Blood Pressure / Arm Blood Pressure.

Normal ABI: Values ​​between 1.0 and 1.4 are generally considered normal, indicating that there is no significant blockage. 

Borderline ABI: Values ​​between 0.9 and 1.0 may suggest borderline peripheral artery disease (PAD) or an increased risk of vascular disease. 

Low ABI: Values ​​below 0.9 indicate peripheral artery disease (PAD), meaning that there may be a significant reduction in blood flow to the legs.

Central and peripheral blood pressure refer to measurements taken at different points in the cardiovascular system, and can provide different information on cardiovascular health.

Peripheral blood pressure (taken from the radial artery of the arm) is higher than central blood pressure (taken from the aorta) to varying degrees. This phenomenon is called “amplification.”

Central blood pressure has been shown to have a superior correlation than brachial pressure with respect to damage to target organs such as the heart or large arteries.

Arterial stiffness can be assessed by measuring pulse wave velocity (PWV), which is a measure of the speed at which a pulse wave propagates along the arteries. Higher velocity indicates more arterial stiffness.

- Lifestyle changes: Managing arterial stiffness often involves lifestyle changes, such as eating a balanced diet, exercising regularly, and quitting smoking.

- Medication: Medication may be prescribed to control blood pressure, lower cholesterol levels, and treat other risk factors associated with arteriosclerosis.

- Regular monitoring: Regular monitoring of blood pressure and arterial stiffness tests can help assess the progression of arteriosclerosis and adjust treatment accordingly.

- Increased blood pressure: A stiff artery cannot expand to accommodate pressure spikes, which can lead to increased blood pressure. 

- Cardiac stress: Arterial stiffness increases the workload of the heart, as it must generate more pressure to push blood through stiff arteries. This can contribute to heart conditions such as heart failure.

- Increased risk of stroke: Arterial stiffness is a significant risk factor for serious cardiovascular events, such as strokes and heart attacks.

- Plaque buildup: Arteriosclerosis is often caused by the buildup of fatty plaques (atheroma) on the artery walls. These plaques can contain cholesterol, lipids, and other inflammatory cells, which cause inflammation and fibrosis (scar tissue formation).

- Fibrosis and calcification: Atheroma plaques cause fibrosis and calcification of the artery walls. Fibrosis makes the arteries less elastic, while calcification (calcium deposits) further hardens the arteries. 

- Loss of elasticity: Due to these changes, the arteries lose their ability to dilate in response to increased blood flow. This loss of elasticity increases the pressure in the arteries because the heart must pump more forcefully to move blood through stiff arteries.

Electrodes are placed on the patient's skin, usually around the neck and on the chest. These electrodes are used to send a low-level electrical current through the chest.

The device sends an electrical current through the body and measures the voltage drop. Changes in impedance are detected and recorded by the impedance cardiography technology.

With each heartbeat, blood is ejected into the arteries and veins. This ejection causes changes in blood volume in the chest, which changes the impedance. The device detects these changes in impedance during the cardiac cycle.

Impedance refers to the resistance of a material to the passage of an electric current. With impedance cardiography, small electrical currents are sent through the body, and the resistance (or impedance) to this current is measured.

The electrical impedance of the thorax changes according to the volume of blood in the thoracic cavity. During the cardiac cycle, as the heart pumps blood through the arteries, the volume of blood in the thorax changes, affecting the electrical impedance.

Changes in impedance are used to create a curve corresponding to the cardiac cycle. By analyzing this curve, the device can estimate various parameters of cardiac function:

Stroke volume (SV): The volume of blood pumped by the heart with each beat. Impedance cardigraphy (ICG) can estimate SV based on changes in thoracic impedance. 

Cardiac output (CO): The total volume of blood pumped by the heart per minute. It is calculated using stroke volume and heart rate. 

Peripheral resistance: This is the resistance that blood encounters as it flows through the peripheral arteries. Peripheral resistance plays a crucial role in regulating blood pressure and blood flow. Increased resistance can lead to increased blood pressure and decreased blood flow to tissues and organs. 

Heart rate (HR): The number of heart beats per minute, measured directly or inferred from the impedance curve.

It is a non-invasive examination, requiring no special preparation or invasive procedures.

It provides continuous, real-time monitoring of heart function.

Indirect calorimetry measures the body's consumption of oxygen (O₂) and production of carbon dioxide (CO₂). The amount of these gases exchanged is used to estimate energy expenditure.

The individual should be in a state of complete rest, usually after an 8- to 12-hour fast, and in a thermoneutral environment.

The individual breathes through a mask or mouthpiece connected to a gas analyzer. Measurements are taken over a specific period, often 15 to 20 minutes.

The oxygen consumption and carbon dioxide production values ​​are used to calculate energy expenditure according to specific formulas.

Resting Energy Expenditure (REE) represents the body's energy expenditure when not engaged in physical activity. It is sometimes referred to as the Basal Metabolic Rate (BMR) when measured under very strict conditions (for example, after a full night's sleep, on an empty stomach, and in a thermo-neutral environment).

REE includes the energy needed for:

Respiration: The energy needed to breathe.

Circulation: Maintaining blood flow and heart function.

Cellular metabolism: The energy needed for cellular processes and maintenance.

Thermogenesis: The energy needed to maintain body temperature. 

Measuring an individual's resting energy expenditure (REE) is essential for understanding their basal metabolic rate and assessing energy needs.

Nutritional assessment: Understanding REE helps plan appropriate caloric intake for weight management, whether for weight loss, gain, or maintenance.

Medical conditions: In patients with certain medical conditions, such as thyroid disorders or serious illnesses, REE measurements can help tailor nutritional support.

Athletic training: Athletes can use REE data to optimize their nutrition and training regimens.

Age: REE generally decreases with age, partly due to loss of muscle mass. 

Gender: In general, men have a higher REE than women, mainly due to greater muscle mass.

Body composition: Muscle tissue consumes more energy than fat tissue, so individuals with more muscle mass tend to have a higher REE. 

Genetics: Genetic factors can influence metabolic rate and therefore affect REE. 

Hormones: Hormonal changes, particularly those involving thyroid hormones, can influence REE. For example, hypothyroidism (reduced thyroid function) can decrease REE.

Over a 24-hour period, you can expect an average of 15 to 30 measurements, giving you comprehensive information about your blood pressure trends over time, including daytime and nighttime averages, as well as how long you've been in target range.

Aktiia’s advanced Optical Blood Pressure Monitoring (OBPM®) technology analyzes optical signals acquired at your wrist to accurately estimate your blood pressure. This approach eliminates the need for painful inflation or the inconvenience of traditional cuffs.

The accuracy achieved (systolic blood pressure accuracy of 0.45 ± 7.75 mmHg and diastolic blood pressure accuracy of 0.38 ± 6.86 mmHg) is similar to that of traditional cuffs, while giving you the freedom and peace of mind to go about your business.

An activity algorithm works with the wristband and determines if you are still enough to take a measurement. If there is significant movement for a period of time, Aktiia will not capture a measurement to ensure you and your doctor only get the most accurate readings. This means that there may be no measurements for certain periods of time, which is completely normal.

High HRV: Generally indicates a well-functioning autonomic nervous system, good adaptability to stress, and better overall health. It is often associated with a predominance of parasympathetic activity.

Low HRV: May suggest reduced adaptability to stress, possible autonomic dysfunction, or increased sympathetic activity. It may be associated with stress, fatigue, or various health conditions.

HRV is most accurately measured using an electrocardiogram (ECG), which records the electrical activity of the heart and provides accurate RR intervals. Data collected from ECGs are analyzed using algorithms to calculate various indicators of HRV.

Stress and Recovery Monitoring: HRV results are used to assess how individuals recover from stress and exercise, and to evaluate overall well-being. 

Health and Fitness: Athletes and fitness enthusiasts use HRV results to optimize training loads and recovery periods. A higher HRV can indicate good recovery, while a lower HRV could signal overexertion or insufficient recovery. 

Medical Conditions: HRV measurements can help diagnose and manage a variety of health conditions, such as heart disease, anxiety disorders, and chronic stress. They provide insights into the balance between sympathetic and parasympathetic nervous system activity. 

Mental and Emotional Health: HRV results can be an indicator of emotional and mental well-being. Lower HRV has been associated with higher levels of anxiety, depression, and stress

Age: HRV generally decreases with age. 

Fitness: Regular exercise can increase HRV. 

Lifestyle factors: Stress, sleep quality, and diet can all influence HRV. 

Medications and health conditions: Certain medications and medical conditions can affect HRV.

HRV measures the variation in time between successive heartbeats, known as RR intervals (the time between the R waves of successive heartbeats on an ECG). It reflects the heart's ability to adapt to different physiological and environmental conditions.

HRV is influenced by the autonomic nervous system, which regulates involuntary physiological functions. The autonomic nervous system has two main branches:

Sympathetic nervous system: Activates the "fight or flight" response, increasing heart rate and decreasing HRV.

Parasympathetic nervous system: Promotes the "rest and digest" response, decreasing heart rate and increasing HRV.

The AngioDefender system measures the health of your endothelium using a process called FlowMediated Dilation (%FMD). It does this by running through a series of inflations and deflations of a blood pressure cuff to analyze the endothelium’s response to increased blood flow – that is, how quickly the blood flow returns to normal after the cuff pressure is released. The healthier your endothelium, the higher your %FMD.

Your personal data is never stored on Everist Health’s servers. Only your healthcare provider has access to your report and personal data.

Problems with %FMD of the brachial artery (the main artery in the upper arm) as measured by the gold standard test, Brachial Artery Ultrasound Imaging (BAUI), is an accurate test of heart disease and potential for future events like heart attacks or strokes. A 2010 study comparing AngioDefender with BAUI shows that the two tests are equivalent.

Before the AngioDefender system, measuring damage to your arteries required highly technical, costly, and even intrusive procedures. Now you can get a precise and accurate assessment of your cardiovascular health, including your heart, in just a few minutes. Plus, you can also witness evidence of your improved health by getting retested after making changes to your diet, exercise, or smoking habits, for example.

+ Your arm and back should be supported, legs uncrossed, and feet on the floor. Your upper arm should be bare, with any sleeve comfortably rolled up (wearing a short sleeve or sleeveless shirt is best).

+ Your healthcare provider will wrap the blood pressure cuff snugly around your upper arm.

+ After starting the test, you will hear a buzzing sound and the blood pressure cuff will inflate. You will feel tightness around your arm, followed by a loosening of the cuff.

+ This process will continue for 15 cycles followed by a five-minute cuff-tightening cycle when your arm might feel a tingling sensation or numbness— this is normal. After an additional 25 cycles, the test will be complete. The test will take under 20 minutes and will generate an AngioDefender Score instantly.

The full-body scan takes about 10 minutes. It is important not to move the extremities during the examination. However, you can breathe normally throughout the procedure.

Clothing restrictions: Remove all metal objects, such as zippers, hooks, buckles, rings and buttons. It is advisable to wear sports clothing that is neither too bulky nor too tight at the waist.

Similar to a blood pressure test, there are factors that can affect an accurate reading of the AngioDefender system. Follow the checklist below to make sure your test result is as accurate and meaningful as possible:

• Do not consume food or non-alcoholic beverages, other than water, for 8 hours prior to the test.
• Do not engage in strenuous exercise for 12 hours prior to the test.
• Do not consume caffeine for 4 hours prior to the test.
• Do not use tobacco products for 6 hours prior to the test.
• Do not consume any recreational drugs or alcohol for 8 hours prior to the test.
• Try not to do anything that may cause youto feel stressed during the test (rapid heartbeat, shortness of breath, etc.).
• Rest and relax for 10 minutes prior to the test.
• Alert your healthcare provider who is administering the test about medications you have been prescribed since your last test.

Note: All guidelines should be followed for optimal results. If you did not follow all guidelines prior to your test, be sure to inform the healthcare provider administering the test. Other important considerations include:

+ Please do not use your mobile device while resting prior and during the test.

+ When taking the test again, make sure it is taken around the same time of day as previous tests. There are minor, but normal daily variations in your endothelial function.

This examination is not recommended for pregnant women. Please notify the technologists of the possibility of an ongoing pregnancy.

The AngioDefender technology takes various readings during the test and converts them to an AngioDefender Score based on Flow Mediated Dilation (%FMD) of the artery in your upper arm. Flow Mediated Dilation (%FMD) measures how quickly the blood flow returns to normal after the pressure in the cuff is released and is an indicator of the overall health of your heart and blood vessels/ arteries. Your healthcare provider interprets this score along with other factors, including age and lifestyle, to paint a total picture of your health risk for stroke, heart attack and other conditions.

The AngioDefender technology assesses your risk of developing cardiovascular diseases before symptoms appear. The AngioDefender test is done like a blood pressure reading, and measures the health of your blood vessels and arteries, or your endothelial function (please see below for an explanation of what the endothelium does). The test produces an AngioDefender Score that represents the relative health of your heart and arteries as well as your risk of cardiovascular disease. These results, along with the advice of a health care professional, can help you to make decisions about making simple changes to your lifestyle or diet, or about medications to protect and improve your long-term heart health.