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Arterial stiffness

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The term “arterial stiffness,” which once referred only to the loss of compliance in the large arteries, is now a comprehensive term encompassing the characteristics of the entire arterial system, including the biochemical-structural-mechanical changes in the small and large arteries, as well as the comparative pressures.

Cardiovascular disease is the No. 1 cause of death worldwide. Heart attack, heart failure and stroke are the top three within the category.

A sudden jump in blood pressure is the most frequent cause of stroke, while myocardial infarctions (heart attacks) are most often caused by a partial or full coronary occlusion, a rupture of vulnerable plaque built up during severe coronary atherosclerosis. In nearly every case, some stage of the process of sclerosis is present.

In order to prevent severe vascular crises, it is essential to identify individuals who are at risk but have not yet developed symptoms. In identifying at-risk individuals, examining the patient for the signs of preclinical atherosclerosis, as well as the identification and treatment of the classic risk factors, are included in the Guidelines for the management of arterial hypertension since 2007.

“Sudden heart attack,” in the literal sense of the word, does not exist. The arterial system prepares for a plaque rupture over the course of years, or even decades, like a ticking time bomb. Most severe events can, therefore, be prevented with early detection of atherosclerosis (with the help of functional and structural tests) and preventive treatment begun in a timely manner.

European Guidelines list the types of target organ damage that can occur even in an asymptomatic patient, but pose a large risk, and therefore testing for these is recommended and mandatory in every hypertension patient. The guidelines emphasize screening for asymptomatic atherosclerosis in as large a pool of individuals as possible, as well as the importance of such testing for high risk of cardiovascular disease because together with the traditional risk factors, it has a greater degree of predictive value.

It is a simple, proven fact today that arterial stiffness is a truly important and independent indicator of cardiovascular risk. The functional and structural changes in the large arteries are partly age-related, but there are several conditions that show a link with accelerated arterial stiffening, such as hypertension, atherosclerosis, and end-stage renal disease, as well as the traditional risk factors (diabetes, dyslipidemia, smoking etc.). That is why arterial stiffness has become a main topic of clinical research in recent years, indicated by the huge increase in publications on the subject.

Growing number of publications on arterial stiffness every year - PubMed data (1991-2010)


Next pages:


Arterial aging


The arterial system’s primary role is to supply the appropriate volume of blood to the tissues and organs. In addition to this conduit function, it must also transform the pulsatile flow from the ventricular contractions into constant flow toward the periphery. The dampening depends on the mechanical characteristics of the arterial wall. This arterial compliance (the degree of arterial elasticity) is a function of the structure of the wall.

The conduit function is determined by the arterial lumen, while the damped oscillation is determined by the visco-elastic properties of the arterial wall and the arterial tree. After each heartbeat the blood pressure wave travels through this system. This is reflected at every discontinuity, primarily at bifurcations. So the reflected wave thus contributes to the direct wave, raising pulse pressure, or systolic pressure, at every point. The superposition of the two waves is determined by the velocity of the traveling wave and the amplitude of the reflection. Arterial compliance, the degree and duration of reflection, the pulse and the ejection duration are all preconditions for optimal arterial function.


Changes in arterial diameter and pressure make it possible at one point to determine direct, local arterial stiffness.
Elastic modulus is the simplest characteristic, which refers to the pressure that is necessary for 100% dilation of the arterial wall.
Another characteristic is arterial distensibility (the inverse of elastic modulus, or arterial compliance), which refers to the change in the diameter due to a given level of pressure.
In addition, there is Young’s modulus, which refers to the elastic modulus in relation to the wall/lumen ratio.

In determining arterial wall stiffness, the measurement of pulse wave velocity (PWV) has spread. In determining aortic stiffness, carotid-femoral PWV or the aortic pulse wave velocity are most common.

Easily accessible methods

Pulse wave velocity is determined by the conduit vessel characteristics and the quantity and quality of the liquid it contains. The loss of arterial compliance appears in an elevated pulse wave velocity: the direct wave propagates faster and so the reflected wave returns earlier, leading to an increase in systolic pressure, decreasing diastolic pressure.

The amplitude of the reflected wave depends on the peripheral vascular resistance. The degree of the increase is called augmentation. The augmentation index (Aix) describes the surplus pressure caused by the wave reflected from the periphery, thereby defining the magnitude of the reflection.

Sustainable elevated peripheral tone does not only indicate poor circulation in the limbs, which is a well known consequence, but also contributes to an increase in aortic pressure, putting an extra workload on the heart.