TechSectors: Arterial Elasticity: The Key to Cardiovascular Health?

MDNG Primary Care, July 2008, Volume 10, Issue 7

Early detection of cardiovascular disease can reduce the huge human and economic impact of this group of diseases.

Early detection of cardiovascular disease can reduce the huge human and economic impact of this group of diseases. Early lifestyle and medical interventions can reduce both the number and severity of serious cardiovascular events. The question remains how to screen individuals before late-stage signs, like hypertension and heart problems, arise.

Arterial elasticity

Arterial elasticity measurement is an emerging technique for detecting cardiovascular deterioration long before it becomes symptomatic, and in ways that imaging techniques, physical examination, or in vitro diagnostics cannot. Normal, healthy arteries are highly elastic. When the left ventricle contracts, blood passes through the arterial system, and the walls expand in response, a phenomenon reflected in the systolic blood pressure. The vessels then recoil to their normal state when the heart is at rest, the point at which the diastolic blood pressure is measured. Facile expansion and contraction depends on the integrity of blood vessels’ epithelial cells, and their ability to release nitric oxide (NO), endothelin, and other factors that induce arterial relaxation. When the left ventricle contracts, a pressure wave precedes blood flow. This wave propagates through the arterial system, and eventually is refl ected back to heart. If the arterial walls have stiff ened, the pulse wave travels much more quickly through the circulatory system, a fact that directly reflects the loss of arterial elasticity.

Abnormally fast pulses refl ect back to the heart sooner than they should. Some researchers believe that this event can stress the left ventricle, thereby creating a self-perpetuating cycle of circulatory system damage. Various risk factors, including aging, genetics, and lifestyle, aff ect the arterial endothelium, causing it to lose elasticity. Individuals with signs of early loss of arterial elasticity cannot change their genes, or the fact that they are aging. But lifestyle modifi cations can mitigate these factors somewhat, and perhaps reverse the eff ects of years of poor diet, lack of exercise, smoking, and other unhealthful practices. It should be stressed that loss of arterial elasticity is a very early-stage, non-symptomspecifi c sign that something is wrong, whereas hypertension is a relatively late-stage event. In other words, by the time an individual presents with high blood pressure the loss of arterial elasticity is well underway. One might ask why, if arterial elasticity measurements provide so much information, the US healthcare system has not embraced the technique more enthusiastically.

For mostly historical reasons, healthcare systems tend to be reactive, rather than proactive. Th e paradigm of diagnosing and treating has only recently begun to be challenged by managed care and a small group of healthcare practitioners who recognize the value of prevention, early diagnosis, and intervention. Interestingly, insurers have led the way in many respects by readily reimbursing for preventive care.

Early warning system

A new instrument, the Digital Pulse Analyzer (DPA), from Meridian Medical, provides early detection of arterial wall stiff ness and arteriosclerosis. As a system for measuring the biological aging pattern of arteries rapidly and noninvasively, DPA serves as an “early warning” system for cardiovascular health throughout a person’s lifetime.

Th e DPA uses a small probe fi tted around the patient’s fi nger, with a light-based sensor to detect the pulse characteristics. An arterial pulse wave, generated by the system software, provides an assessment of how large and small arteries behave when blood passes through them. Unlike a high blood pressure reading, a lessthan-optimal arterial elasticity measurement does not indicate a person already has a serious medical condition, but it does indicate increased risk for developing such a condition. It is up to the patient, armed with information from their caregiver, to determine whether they will follow the road toward cardiovascular health, or the road toward higher risk. Rather than receiving a wakeup call through a serious cardiovascular event, the individual who has been monitoring arterial elasticity may receive the call years earlier.

Debbie Williams, RN, is VP of Medical Affairs at Meridian Medical.