Arterial Stiffness

Arterial stiffness is one of the earliest detectable signs of changes in the arterial wall, occurring as arteries lose their natural flexibility and become rigid, which can lead to serious health complications throughout the body.

Table of contents

• What Is Arterial Stiffness?
• What Causes Arterial Stiffening?
• How Arteries Normally Work
• Health Consequences of Arterial Stiffness
• Measuring Arterial Stiffness
• Relationship with Hypertension
• Prevention and Treatment Approaches

What Is Arterial Stiffness?

Arterial stiffness refers to the decreased flexibility of the walls of large arteries, such as the aorta. Normally, these arteries can stretch and relax easily with each heartbeat, acting like flexible tubes that help blood flow smoothly through your body^[1].

Think of healthy arteries like rubber bands that can stretch and bounce back. When arteries become stiff, they lose this ability and behave more like rigid pipes. This occurs because special fibers that help arteries stay stretchy (called elastin) break down, and tougher fibers (called collagen) build up instead^[5].

Arterial stiffness is closely related to a condition called arteriosclerosis, which is a collective term for different vascular diseases. This should not be confused with atherosclerosis, which involves plaque buildup inside arteries. While atherosclerosis is characterized by the accumulation of cholesterol and fatty substances in the inner layer of the artery (the tunica intima), arterial stiffness primarily affects the middle layer (the tunica media) and involves structural changes throughout the arterial wall^[4].

What Causes Arterial Stiffening?

Arterial stiffening can occur for several reasons. One of the most common causes is simply aging. As you grow older, the tissues throughout your body gradually stiffen and weaken as levels of elastin and collagen decline, and your arteries are no exception^[15].

However, arterial stiffness can also occur prematurely due to various cardiovascular risk factors. High blood pressure (hypertension) is a major contributor, as chronic high blood pressure can lead to arterial wall damage through mechanical stress, endothelial dysfunction (damage to the inner lining of blood vessels), increased inflammation, and oxidative stress^[6].

Other conditions that increase the risk of arterial stiffness include diabetes, smoking, obesity, and chronic kidney disease. These conditions cause structural and functional changes in the media of the arterial wall, resulting in reduced distensibility (the ability to expand)^[2].

A third significant risk factor is calcification, where calcium deposits build up in the artery walls, making them harder. Type 2 diabetes, which results from high blood glucose levels, is also known to increase the risk of arterial stiffness^[15].

Research has also shown that arterial stiffness is increased in several other conditions, including systemic sclerosis (an autoimmune disease characterized by endothelial dysfunction and fibrosis), inflammatory bowel disease, and thyroid disorders such as hypothyroidism and hyperthyroidism. In some of these conditions, proper treatment can actually reverse arterial stiffening^[2].

How Arteries Normally Work

To understand arterial stiffness, it helps to know how healthy arteries function. Arteries are blood vessels that deliver oxygen and vital nutrients to all the vital organs and body parts. The heart pumps blood through these vessels, and with each pulse, blood flows to circulation throughout the body^[1].

At each systole (beat of the heart), the heart squeezes to pump out blood. At each diastole (the time between two beats), the heart gets time to fill up with blood^[1].

The pressure exerted on the walls of the blood vessels during systole is lowest if the blood vessels are highly compliant or have low stiffness. People who have elastic and highly compliant arterial walls have a narrow pulse pressure (the difference between systolic and diastolic pressure). This reflects low wall tension, which means the workload of the heart is low^[1].

Large elastic arteries, such as the aorta, play a vital role in storing blood that is pumped from the heart during its contraction phase and releasing it steadily during the resting phase. This function ensures that blood flows smoothly to different parts of the body. In simple terms, large elastic arteries act like cushions, absorbing pressure changes and reducing the strength of blood flow. This helps protect smaller blood vessels from harmful changes in pressure^[5].

When the heart contracts, it generates a pulse or energy wave that travels through the circulatory system. The speed of travel of this pulse wave (called pulse wave velocity or PWV) is related to the stiffness of the arteries. The loss of elasticity and increased rigidity results in increased velocity of pulse waves since they travel faster in stiff arteries^[2].

Health Consequences of Arterial Stiffness

Arterial stiffness plays a significant role in many serious health conditions and is associated with an increased risk of cardiovascular events such as heart attack (myocardial infarction), hypertension, heart failure, and stroke^[3].

The primary sites of organ damage following an increase in arterial stiffness are the heart, the brain, the placenta, and the kidneys. Stiffened arteries compromise what is known as the Windkessel effect of the arteries. This effect buffers the pulsatile ejection of blood from the heart, converting it into a more steady, even outflow. This function depends on the elasticity of the arteries^[3].

When arteries become stiff, they struggle with blood pressure changes, raising systolic blood pressure and pulse pressure. The resulting increased systolic pressure further hardens arteries, creating a harmful cycle of inflammation and calcification^[6].

Arterial stiffness contributes to numerous serious health issues, including high blood pressure (which is often the primary immediate consequence), stroke, heart attack, Alzheimer’s disease and other forms of cognitive decline, Parkinson’s disease, liver disorders (especially non-alcoholic fatty liver disease), kidney disorders (including end-stage renal disease), type 2 diabetes, and damage to the blood-brain barrier^[14].

The stiffness can extend into capillaries, preventing these tiny blood vessels from delivering oxygen and nutrients to organs. This damage can manifest not only as heart attack and stroke but also as dementia, kidney failure, and other disorders^[7].

Current research indicates that arterial stiffness is an independent risk factor for cardiovascular diseases and represents a potential target for personalized prevention and therapeutic approaches^[4].

Measuring Arterial Stiffness

Arterial stiffness is commonly measured as carotid-femoral pulse wave velocity (cfPWV) or brachial-ankle PWV (baPWV). The cfPWV is the standard for measuring large artery stiffness in Europe^[3].

For baPWV, general cutoff values for cardiovascular risk assessment are less than 1400 cm/s for low risk, 1400-1800 cm/s for intermediate risk, and greater than 1800 cm/s for high risk. Increased cfPWV and baPWV values predict an increased risk of new-onset hypertension in apparently healthy people^[3].

The measurement typically involves recording pulse waves at both the carotid arteries in the neck and femoral arteries in the thighs and comparing them. Some devices use special blood pressure cuffs, while others use sensors. When the heart contracts, a pulse of energy passes through the circulatory system. Arterial stiffness affects the speed at which this pulse wave travels, so measuring the pulse wave is a good indicator of the stiffness of arteries^[15].

For smaller arteries and arterioles, the Augmentation Index (AIx) is the key parameter used to evaluate stiffness^[5].

Various devices are available that measure arterial stiffness parameters, and a 2024 paper reported that the use of PWV, previously a predominantly research-focused tool, had become a marker of clinical importance^[3].

Relationship with Hypertension

Arterial stiffness and hypertension are closely related and significantly influence each other. Chronic high blood pressure can lead to arterial wall damage by mechanical stress, endothelial dysfunction, increased inflammation, oxidative stress, and activation of the renin-angiotensin-aldosterone system (RAAS). Hypertension also increases collagen fiber production and accelerates elastin fiber degradation^[6].

The stiffer and harder the blood vessel walls, the wider the pulse pressure and the more the heart has to work to pump blood into the arteries. In persons with stiffer arterial walls, only a small fraction of each cardiac stroke volume can be utilized for blood circulation without increasing blood pressure. Thus, to compensate for the lack of blood in the peripheries, blood pressure rises. These persons have relatively high systolic and pulse pressures and a low diastolic pressure^[1].

As arterial stiffness escalates, systolic pressure increases and diastolic pressure decreases because of the premature merging of the fast-reflected wave with the forward wave. The increased systolic pressure triggers left ventricular hypertrophy (thickening of the heart’s main pumping chamber), while the diminished diastolic pressure impairs coronary blood flow^[6].

This creates a vicious cycle: high blood pressure causes arterial stiffening, which in turn raises blood pressure further, creating a harmful cycle of inflammation and calcification^[8].

Prevention and Treatment Approaches

Arterial stiffness data can predict target organ damage and future cardiovascular events in hypertensive patients. Early detection of arterial stiffness aids in initiating preventive measures and treatment plans to protect against progression of vascular damage^[6].

Fortunately, there are practical steps you can take to prevent your arteries from losing their natural flexibility. Healthy lifestyle changes are known to reduce arterial stiffness. These include regular exercise, which is important for keeping all tissues and organs healthy by increasing blood flow and preventing tissue weakening^[15].

Research suggests that stretching may help guard against arterial stiffness. While certain stretches may delay arterial stiffening, more research is needed in this area^[20].

Diet also plays a significant role. Nutrients that may help reduce arterial stiffness include vitamins D and K, which help keep calcium out of the arteries and work together to slow or prevent arterial stiffening. Clinical trials have shown their effectiveness in managing arterial calcification^[17].

Fish oil supplements contain omega-3 fatty acids (DHA and EPA), which reduce inflammation, clotting, and blood vessel constriction, improving the flexibility of arteries^[15].

Other dietary factors that may help include foods rich in nitric oxide (such as leafy greens, beets, and garlic), potassium (found in spinach, potatoes, and avocados), and magnesium (found in leafy greens, nuts, and seeds). These nutrients help regulate vascular tone, prevent arterial stiffness, and support overall heart function^[19].

Pharmaceutical interventions that are known to reduce arterial stiffness include RAAS blockers (medications that affect the renin-angiotensin-aldosterone system) and statins. Further research is needed to determine if improving arterial stiffness will enhance prognosis in hypertensive patients^[6].

Bariatric surgery has also been shown to improve arterial stiffness in extremely obese subjects^[2].

It is important to note that while arterial stiffness can develop and worsen over time, adopting a proactive approach through lifestyle changes and appropriate medical interventions can help improve arterial health and potentially reverse some of the effects^[18].