Why Measure Arterial Stiffness
Arteries carry Oxygenated blood across the body. Every tissue, muscle, and living cells need Oxygen. Once tissues absorb Oxygen, the deoxygenated blood is collected in veins from capillaries. The veins then carry this deoxygenated blood to the heart.
The body’s blood pressure is not constant. It is varied all the time. For example, you see a snake. Now you have to either fight or run. The body increases heart rate and blood pressure both to supply more oxygen to your muscles. In order to increase blood pressure, the artery diameter is reduced. This process is called Vasoconstriction. Same way when you go to sleep, the body preserves energy. It reduces blood pressure. This is done by increasing the diameter of the arteries. This is called Vasodilatation.
Therefore arteries are flexible elastic oxygenated blood-carrying vessels. This elasticity is important for maintaining the flexibility of the blood pressure in the body.
Arterial stiffness is the disorder of the arteries when the elasticity of the arteries is reduced. Following are the primary reasons for arterial stiffness.
When there is plaque formation inside the arterial walls called the endothelium, the arteries lose their flexibility. Vasodilation in particular becomes harder. Hence body can’t easily get into relaxed mode. This is called Atherosclerosis. Calcium, glucose, thrombotic repair, and other such molecules causes this plaque.
Another reason for stiff arteries is obviously smoking. Smoking increases Carbon Monoxide gases inside asteroids(small arteries) causing stiffness.
The third reason is vascular biological aging. Our body’s chronological age is the total age since the day we were born. However, stress, struggle, and worry accelerate our aging. Like the rest of the body, the arteries also age faster. This excess aging is called biological aging. As the arteries age, stiffness increase.
Endothelial dysfunction is referred to as the cellular or Genetic dysfunction in the inner cells of the arteries. Even if there are no other disorders, endothelial cells may be dysfunctional due to various reasons. Even without atherosclerosis, vasoconstriction, vascular aging, arteries may lose their elasticity
When blood pressure remains higher for a very long period of time, it is called Hypertension.
Therefore the actual disorder is Arterial Stiffness, the result of that disorder is Hypertension.
If we can measure Arterial Stiffness, then we can predict future hypertension risk. Accurate measurement of Arterial Stiffness will also help us with a timely intervention that can prevent hypertension.
Note:- Because irrespective of the way an arterial stiffness has happened, it resembles atherosclerosis, we shall use atherosclerosis as the reason for arterial stiffness in this article for simplicity.
Difference Between Arterial Stiffness and Atherosclerosis
We have already read that arterial stiffness can be caused by:
- Vascular Aging.
- Endothelial Dysfunction.
- Plaque formation in the arteries.
Smoking also results in Endothelial dysfunction. Endothelial dysfunction accelerates atherosclerosis and vice versa. Vasoconstriction is a temporary phenomenon that is followed by vasodilatation. Vasoconstriction and vasodilation together are called the vasomotor function, or arterial elasticity. Therefore endothelial dysfunction is a measurement of impaired vasomotor function. All the conditions eventually result in Arterial Stiffness.
Therefore, Atherosclerosis causes Arterial Stiffness, but arterial stiffness doesn’t mean an Atherosclerosis. Arterial Stiffness means, there can be atherosclerosis, vascular aging, or endothelial dysfunction.
How Arterial Stiffness is Currently Measured?
CT Scan gives us a Calcium score. A calcium score of 100-300 suggests moderate plaque deposits. If doctors do an intervention at this stage, then the plaque can be removed by lifestyle changes and some medicines. Then you won’t have Hypertension.
Calcium ions are heavier atoms. They enter the endothelial cells and kick out the potassium atoms. Potassium is needed for Vasodilatation. Therefore arteries remain stiff. You may already be knowing that one of the common drugs that are prescribed to heart and hypertensive patients is Calcium channel blocker.
A Coronary Artery CT scan, that gives us the Calcium score costs you around ₹ 2960.0(Delhi) to ₹ 3360.0(Bangalore). Arterial stiffness measurement using Calcium Scoring through Coronary Artery CT scan(Heart CT scan in short) costs $400 to $800 in the USA.
Screening of Arterial Stiffness Using Pulse Wave Velocity
You saw in the last section that a Heart CT scan is not a scalable process. Neither such facilities are available everywhere, nor they are affordable by a large population group. Therefore doctors often prefer to do a screening test before referring their patients to heart CT.
Screening tests are much faster. A doppler or pulse wave velocity test is one where arterial pulse speed is measured in all four limbs. Then the velocity difference is calculated. If there is no difference in the speed of the signal in all four limbs, then all the arteries are carrying blood nicely and there is no plaque formation. If the velocities differ, then obviously in some of the arteries there is a blockage.
This test costs around ₹ 600- ₹ 100 In India, and up to $100 in the USA.
Endothelial Dysfunction Measurement
Endothelial Dysfunction is currently measured by the Upper Arm Brachial Artery Ultrasound1. Firstly the artery is occluded(means choked) through a BP calf for 5 minutes. Obviously, this causes vasoconstriction. Then the calf is released, and Ultrasound is conducted. After the calf is released, due to the natural vasomotor phenomenon, the brachial artery must be dilated. Right?
However, if there is an Endothelial dysfunction, the vasodilation function gets impaired, which is detected in the Ultrasound.
Can I Measure Arterial Stiffness at Home?
Lyfas is always here for you. We search, innovate, invent, and perfect methods for you that help you to screen different medical conditions from home. Healthcare is not a premium. It is one of the basic human rights. We work towards making healthcare facilities available in your home anywhere, anytime, when you need them, without putting any burden on your pocket.
This method that we are going to use is called an Arterial Branching Index(ABI). You Require a BP machine for this.
Arterial Branching Index
You have to take blood pressure in the supine position(lying down) in the left hand, right hand, left leg, and right leg. You already know how to take calf BP in your hands, follow the below image for measuring Leg BP.
Note down all the four BP values in the following table.
|Position||Systolic(First Number)||Diastolic(Second Number)|
Now use the ABI Calculator to see your Arterial Stiffness Risk Factor
Why do I have Arterial Stiffness When My Lipid Tests Are Normal and I don’t have Diabetes or Hypertension also?
Stress and anxiety are two primary causes of physiological hypertension, also called vasoconstriction. Remember, blood pressure changes in the body all the time. Therefore the test you conducted at home gives you arterial stiffness at this moment in time. Though ABI generally remains very consistent, it doesn’t tell the reasons well. Moreover, if your lipid is normal, you may get confused about why you have arterial stiffness. Don’t worry, we will help you with this also.
You can check your Stress and Anxiety with our clinically validated online questionnaire-based mental health instrument. If you have moderate to high test and anxiety, then they are the reasons behind your Arterial Stiffness.
Can I Measure Arterial Stiffness From Blood Test?
Dyslipidemia may cause Atherosclerosis, but not necessarily they would always cause atherosclerosis. There is an exceptional tool called Framingham Risk Score(FRS) that provides 10 years’ cardiac risk from the blood test, your hypertension status, and diabetes. Because Arterial Stiffness is highly correlated with the Framingham Risk Score, FRS can be used as a marker for arterial stiffness screening.
As you are visiting our site, we want you to derive maximum value from our tools and platform. We provide you with several comprehensive methods to do self-diagnosis and self-assessment for free.
The drawback of the Existing Available System for Arterial Stiffness Measurement
- HR CT is extremely expensive and is not available to a major population group.
- Pulse Wave Velocity and Doppler Tests are done in only specialized preventive cardiology and Diabetes clinics.
- Even though our home-based protocol provides a very good screening for arterial stiffness, it can not differentiate between a Physiological Vasoconstriction and a Pathological Vasoconstriction.
- Pulse wave velocity too can not distinguish between arterial stiffness and physiological vasoconstriction.
- A heart CT scan only measures Arterial Stiffness in the coronary arteries, but not in the peripheral arteries.
- Doppler or PWV test can only measure Arterial stiffness in the peripheral arteries, but not in the coronary arteries.
- Existing Systems do not provide a differential diagnosis for Hypertension.
- Existing tests do not take into account the Arterial Stiffness due to Vascular aging, which is caused by Mental Health Problems.
We have an immediate need for a home assessment of arterial stiffness that can accurately screen and detect arterial stiffness anytime, anywhere without putting a burden on your pocket. The meaning of physiological arterial stiffness or vasoconstriction is when the body is under stress, it reduces the artery diameter to increase the blood pressure.
Lyfas Clinically Proven Research on Measurement and Assessment of Arterial Stiffness and Differential Diagnosis
- Download Lyfas’s clinically-proven mobile application.
- This turns your mobile phone into a smart diagnosis device.
- You put your fingertip on the rear mobile camera for three minutes. Lyfas captures your pulse signal from the finger capillary.
- Capillary has both arteries and veins.
- Using our signal processing, we separate the arterial signals from the capillary pulse.
- Then using our revolutionary algorithms, we find out your arterial stiffness.
- Lyfas also incorporates pulse rate variability, a surrogate marker for Autonomic Nervous System function. Because the autonomic nervous system is responsible for vasomotor movement and arterial diameter physiology, Lyfas provides Endothelium Dysfunction measurement.
- Lyfas also incorporates Orthostatic Homeostasis. This is a measurement for posture change homeostasis due to baroreceptor impairment. Baroreceptor impairment increases the risk of Posture Orthostatic Tachycardia(a condition when your heart rate shoots over 100 as you stand up). Orthostatic Homeostasis impairment is a natural outcome of Arterial Stiffness. Hence Lyfas provides you with a fascinating differential diagnosis of Arterial Stiffness and Endothelial Dysfunction.
See how easy it is to take a full mind-body health assessment test from your mobile, just under three minutes from the video below.
Lyfas Sample Report Comparision of Normal and Arterial Stiffness Positive
- Look into the Endothelial graph on top right corner. It represents Vascular structure. Small lumen as in this case represents vasoconstriction (Atherosclerosis traces)
- Left bottom graph is the body’s balance of Sympathetic (SNS), Parasympathetic (PNS) and Stress. If SNS>> PNS, then it is Sympathetic Dominance which means that the body is not recovering. It is a pointer that the subject has immediate health issues. For cardiac/hypertensive patients, it may point to an elevated risk of cardiac arrest and heart failure. For such a patient, an immediate hospital visit on such traces is advised
- The reason for poor vascular structure is shown from left top graph. We can see that over stress and Arterial stiffness are the reasons.
- Bottom Right graph, if flat(no variations, here it is not) then represents body pain and neuropathy.
Why Clinicians Must Use Lyfas Arterial Stiffness For Their Patients?
- Simple non-invasive hassle-free Clinically Proven highly accurate 3 minutes test from the mobile.
- No need to invest in any other hardware.
- No maintenance fee. No Biowaste. No specialized technician is needed.
- Visual representation of the Endothelium.
- Distinguishes between Sympathetic Dominance led to Physiological Vasoconstriction and Arterial Stiffness.
- Captures arterial stiffness in peripheral arteries, as well as in the coronary arteries.
- Can easily be used for before and after intervention result comparison.
- Additional biomarkers like Biological Age can be used for Prognosis and treatment effectiveness measurement.
- Additional snapshot of metabolic health and risks for you to be able to correlate Arterial Stiffness with metabolic disorders such as insulin resistance.
- Can help you determine the root cause of Arterial Stiffness. Stress, Sympathetic Dominance, etc.
- Your patients can use the application for home monitoring during the treatment for data-driven insights.
- Helps you with differential diagnosis of vasomotor function, baroreceptor impairment, arterial stiffness, atherosclerosis, vascular aging, and sympathetic dominance.
Never Use the word “Essential Hypertension” anymore, use our differential diagnosis to know the type of hypertension. Improve your treatment efficacy multiple times by targeting the right channels.
What is the Principle Used in Measuring Arterial Stiffness by Lyfas?
Lyfas mobile application lights your finger capillary with the smartphone flash-light. This light is absorbed inside your vascular network. If there is no arterial stiffness, then the light traverses without any hassle. However, if arteries are stiff, or there is plaque formation, then the light can’t travel smoothly. Light beams are reflected by multiple blockages. Smooth arteries also do not absorb much light. But the stiff arteries absorb a lot of light. Therefore by using the signal processing technique, we detect various changes in the arterial pulse, which is extracted from the capillary pulse from your smartphone’s rear camera. These changes are classified using our AI and ML platform to detect Arterial Stiffness.
Towards Corroborating the Arterial Stiffness with Lyfas Optical Biomarkers: A Novel Study
This research paper is published in the American Journal of Biomedical Science(ISSN: 1937-908). The paper provides detailed invention, clinical and statistical validations.
Vascular aging (VA) increases the risk of Cardiovascular Disease (CVD) and premature deaths. Increased VA is attributed to the extent of the Arterial stiffness index (ASI), which is evident in smokers, diabetics, hypertensives, etc.
The authors of this paper have discussed the usage of a smartphone- based healthcare instrument, called Lyfas that works with the principle of arterial photoplethysmography
(APPG) and estimates the Pulse rate variability (PRV), which surrogates for the Heart rate variability (HRV) and its correlated digital cardiovascular biomarkers (CVb). PRV reflects cardiovascular autonomic modulation, which helps obtain the ASI by Lyfas.
To establish the inter-relationships of the CVb and ASI using Lyfas. Methods: (i) Lyfas assess the ASI from the 2nd derivative of the photoplethysmography (SDPPG)
the waveform of the capillary arteriole at the tip of index fingers using the camera sensor. From SDPPG, ASI is computed. (ii) Lyfas simultaneously captures the CVb such as SDNN, RMSSD, HR, HRV score, pNN50, SD1/SD2, and LF/HF. (iii) Linear regressions (LR) and One-way ANOVA, and Pearson’s interclass correlations (‘r’) are applied to check the interrelationships of (a) ASI with that of (b) CVb in 116 adults (58 females and males, each) within the age group of 30-60 years and above.
Hypersensitivity of Lyfas has been tested by taking the test thrice a day at a gap of 8 hours. The variance and the ranges are measured for hypersensitivity analysis.
The study found that the ranges and variances fall within the normal limits. For female
hypertensives, SDNN, and LF/HF are statistically significant to predict ASI with correlation (r) values of 0.79 in the age group >60 years and -0.98 in the age group 41-50 years, and 0.99 in the age group 41-50 years, respectively.
In the case of smokers, SD1/SD2 is negatively correlated (-0.77) with ASI and is statistically significant. male smokers, RMSSD, and HRV are statistically significant to predict ASI with correlation (r) values of 0.59 in the age group 30-40 years and 0.96 in the age group 41-50 years and for HRV 0.96 in the age group 41-50 years, respectively.
In the case of hypertensives, SDNN is negatively correlated (-0.89) with ASI in the age group of 41-50 years and is statistically significant. No biomarker showed a significant correlation in diabetics in this sample.
Lyfas is a robust clinical-grade instrument and the CVb captured by it can predict the ASI and the vascular age in
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I am Worried About My Cardiac Health. What Should I Do? How Can Lyfas Help Me?
You may be having this question because of elevated cardiac risk factors. You might have also taken the tests using the tools in this article, and may find that you have an Arterial Stiffness. You are asking this question because of any of the following possible reasons:-
- Your clinicians must not have explained to you why you have the problem.
- You are taking too many medicines and may want to reduce the medicines.
- You may want to have a better diagnosis of your condition.
- You may want to understand your condition better for self-diagnosis, monitoring, and home diagnosis.
- You may be worried about the seniors in your home and maybe looking for a sustainable personalized solution for minimizing their risk.
- You may be going through mental or emotional health problems that your clinicians have failed to correlate with your cardiac risk.
- You may be going through excess worry about your own cardiac risk, as news of many youngsters suffering and dying from a heart attack has become common these days.
You have already read the details in this article. You have already experienced the amount of power we give to our patients. You might have already built trust for our services after reading this article and using the free tools for your self-assessment. You want to explore how we can take care of your arteries, and cardiac health, like no other organization.
Just fill out the form at the bottom of the page. Or send us a Whatsapp message. We do not charge for consultancies. We protect your data and sensitive information by life.
- 1.Verma S, Buchanan MR, Anderson TJ. Endothelial Function Testing as a Biomarker of Vascular Disease. Circulation. Published online October 28, 2003:2054-2059. doi:10.1161/01.cir.0000089191.72957.ed