Leading US hypertension experts unveiled a new definition of hypertension at the American Society of Hypertension Inc. (ASH) Twentieth Annual Scientific Meeting.
The group has expanded the definition of hypertension beyond the numbers obtained from a blood pressure reading, and instead, urge that blood pressure be viewed as a part of a patient’s overall risk for cardiovascular disease. The goal of the new definition of hypertension is to improve the way physicians conceptualize, diagnose and treat hypertension by encouraging them to think about the disease earlier than they commonly do now, with the ultimate goal of reducing the risk of cardiovascular disease linked to high blood pressure, such as heart attack and stroke.
“For many years we have defined hypertension primarily by blood pressure levels, but in many cases elevated blood pressure is an effect, and not the cause of hypertension,” said Dr. Thomas Giles, president of the American Society of Hypertension and professor of medicine at the Louisiana State University School of Medicine in New Orleans, LA. “Our new definition incorporates the presence or absence of risk factors, early disease markers and target-organ damage, and more accurately represents the different physiological abnormalities in the cardiovascular system and other organs caused by hypertension.”
The expanded classification criteria are intended to improve the identification of at-risk individuals at an earlier point in the progression of hypertension. It focuses greater attention on a patient’s overall, individual cardiovascular risk - blood pressure being an important part of this risk. Broader classification criteria should assist doctors in identifying patients who are at risk for cardiovascular problems, even when their blood pressure numbers fall in the ‘normal’ category.
The new definition of hypertension, developed by the Writing Group of the American Society of Hypertension (WG-ASH) characterizes the disease as a progressive cardiovascular syndrome with many causes that result in both functional and structural changes to the heart and vascular system. The authors of the new definition write that the early stages of hypertension can begin before an individual develops sustained elevated blood pressure, and can progress to damage in the heart, kidneys, brain, vasculature and other organs, often leading to premature morbidity and death. Cardiovascular disease is the number one cause of death in the US, followed by cancer and stroke, according to 2001 data released by the Centers for Disease Control and Prevention.
Federal guidelines published in 2003 classified hypertension by blood pressure measurements, establishing a systolic measurement, or the upper number, of 120 mm Hg, and a diastolic measurement, or the lower number, of 80 mm Hg as normal blood pressure. Higher blood pressure levels were graded in stages, with stage 2 hypertension – readings of 160/100 mm Hg and higher – being the most severe. The new WG-ASH definition of hypertension also includes staging of hypertension, but in addition to blood pressure measurements, takes into account other factors indicating cardiovascular risk. The new definition means that instead of relying on blood pressure numbers alone to predict each patient’s risk of developing cardiovascular disease, this risk must be assessed on an individual basis by taking several factors into account. Thus one person with a blood pressure of 130/80 mm Hg may have signs of damage to their heart, kidneys or eyes caused by high blood pressure – and thus be at high risk for cardiovascular disease – while another person with the same blood pressure reading may have no such organ damage, and therefore be at lower risk for a heart attack or stroke.
“As a physician, responding to a patient’s elevated blood pressure in isolation represents only a partial understanding of hypertension,” said Dr. Giles. “We now know that hypertension is associated with many measurable cardiovascular indicators beyond blood pressure measurements.”