Sept. 27, 2002 -- Forget what you've heard about healthy blood pressure -- if you are one of the thousands of Americans with high blood pressure or hypertension, ask yourself, How low can you go? Because the lower you go, the more likely you will be able the reverse the heart damage caused by high blood pressure.
The latest evidence of this less-is-more approach to high blood pressure comes from Japanese researchers who report that lowering blood pressure to less than 130/85 reverses the arterial stiffness caused by high blood pressure. Stiff arteries, says Ernesto Schiffrin, MD, "increase the risk for heart attack and stroke."
The American Heart Association defines high blood pressure as higher than 140/90. Typically, doctors treat to the goal of less than 140/90.
In recent years, several other studies have pointed to added benefits for really aggressive approaches to lowering blood pressure, says Schiffrin, who led the program committee at the Heart Association's High Blood Pressure Research Conference where the Japanese study was released.
In the new study from Japan, 142 patients were randomized to either the standard treatment goal -- meaning a blood pressure less than 140/90 -- or to a group in which the target blood pressure was the super-low goal of less than 130/85. When the study started, the average blood pressure for all patients was 177/101.
After a year, the 71 patients in the low-target group had average blood pressures of 129/78, which was good, but Atsuhiro Ichihara, MD, says the real benefit was seen in an indicator called pulse wave velocity or PWV. This measures how fast blood is rushing between the brachial artery in the arm and the tibial artery in the ankle.
It is this rushing blood caused by high blood pressure that causes the arterial walls to react by stiffening. When the blood pressure is lowered, it slows blood flow, and the walls relax.
After 12 months, the patients who had the lower blood pressure goal had average PWV decline from 1,779 cm/sec to 1,621 cm/sec. "Healthy people with normal blood pressure have PWV in the 1,600 cm/sec range," says Ichihara, of the Keio University School of Medicine in Tokyo. But patients in the normal treatment group had no difference in PWV.
Ichihara said patients in both groups used a variety of blood pressure medicines to achieve lower pressure and no one drug was more effective than others.
Schiffrin says the studies that find an advantage for lower blood pressures have researchers like him thinking that it may be time to change the current guidelines. He says that a national commission on blood pressure works with the National Institutes of Health and the American Heart Association to re-evaluate blood pressure recommendations every few years. In recent years, each new set of recommendations featured new definitions for "normal" blood pressure -- each lower than the previous recommendations. Schiffrin says that the commission is expected to meet next year, and he predicts that new guidelines will be issued by sometime in 2003.
"I suspect they will lower the goals," he says.