High blood pressure may be one of the top killers in the country, but you'd never know it by the way we're behaving, say scientists attending the annual congress of the Society for Critical Care Medicine (SCCM).

"Research shows that some 73 million people in the U.S. have high blood pressure, yet many of them don't even know it. And among those that do, a large number are not taking the medications they need to control it," says Dr. Christopher Granger, a cardiologist at Duke University Medical Center.

"We've discovered that these patients are getting highly variable treatment. Moreover, we also found out that we aren't doing a very good job following up with these folks once they leave the hospital," he adds.

Granger and colleagues at nearly two dozen institutions around the country created a special registry to find out what happens to patients with acute, severe hypertension -- those with blood pressure readings above 160/110 -- when they come to an emergency department or critical care setting for treatment.

They found that although 90 percent of them already had a diagnosis of high blood pressure, about a quarter of them were not taking the medicines they were supposed to. The researchers also found that extremely high blood pressure was related to high complication and death rates. Many of the patients already had major organ damage and over six percent of them died in the hospital.

Upon discharge, most of the patients were given prescriptions for at least two medicines, but 41 percent had to be readmitted within three months. What may be most unsettling, however, is the fact that the investigators could not find any evidence in the discharge records of about 60 percent of the patients that there had been any attempt to schedule a follow-up appointment for them.

"We are apparently turning large numbers of patients back out into the community without appropriate follow-up and care," says Granger. "Severe hypertension is a very common problem, but we really know very little about it. There is a huge need to improve care for these patients."

Dr. Solomon Aronson, an anesthesiologist at Duke, sees danger in high blood pressure from another angle. Aronson has spent years trying to discover the "sweet spot," or ideal range, of blood pressure during cardiac surgeries. Aronson led a team of investigators that analyzed over 3 million blood pressure readings in the records of 5238 cardiac surgical patients at Duke over a nine-year period.

They discovered that when patients' systolic blood pressure readings fell below 95 or went higher than 135, there was a greater risk of death within the following month, with the risk of death increasing with the amount and duration of the deviation from that range.

"This is the first time that anyone has determined the optimal range for blood pressure management during these procedures," says Aronson, who adds that different ranges might be more appropriate for other types of surgery.

Aronson says blood pressure management has become such a routine responsibility during surgery that physicians may have developed an attitude of "therapeutic inertia." "These data suggest that drifting off the road and onto the shoulder when you drive is not good for you. We're beginning to define the width of the road."

"We still have a long way to go before we can understand and successfully manage the subtle and complex effects that targeted blood pressure control has on overall health," he says. "Just because high blood pressure is a common problem doesn't mean that we know how best how to deal with it."

Both Aronson and Granger are paid consultants for The Medicines Company, which supported the creation of the new, acute, severe hypertension registry at Duke and is also developing an experimental drug for the management of high blood pressure.

Adapted from materials provided by Duke University Medical Center, via EurekAlert!, a service of AAAS.