How much can lower blood pressure cut health risks?
PITTSBURGH —A dramatically lower systolic blood pressure — that big number after the bloodpressure cuff has deflated — may be necessary to reduce risk of cardiovascular and kidney disease and even death.
Current guidelines to keep systolic blood pressure below 140 millimeters of mercury (mm Hg) might need to plummet below 120 to reduce the health risks of hypertension.
Don’t panic and don’t let your blood pressure spike. Just stay tuned.
“I would say to wait for more information,” said Indu Poornima, the Allegheny General Hospital director of nuclear medicine and director of the hospital’s Women’s Heart Center. “But it’s always worthwhile to have a discussion with your doctor to see if the patient would benefit with a more aggressive target.”
In September, the National Heart, Lung, and Blood Institute stopped its Systolic Blood Pressure Intervention Trial, or SPRINT, when results showed that patients maintaining systolic bloodpressure levels below 120 experienced 30 percent fewer cardiovascular events — heart attacks, heart disease and strokes — than those following current guidelines of below 140, reporting 25 percent fewer deaths.
The Data and Safety Monitoring Board that monitors such studies recommended the trial be halted. It would be unethical to deny all 9,300 study participants the option of seeking better blood pressure control to reduce health risks.
The NHLBI now is analyzing results before publishing them in a medical journal while continuing part of the study focused on whether elevated blood-pressure levels affect cognitive function in older adults.
“We’re working hard to finish the paper and submit it to a journal. I don’t want to specify a date, but it will be within a few months,” said Lawrence Fine, NHLBI’s SPRINT project officer. “Once a paper of this kind with these kinds of results is published, I’m sure that any future guideline group will look at it and integrate it with other research into their recommendations for new guidelines.
According to the institute, “high blood pressure, or hypertension, is a leading risk factor for heart disease, stroke, kidney failure, and other health problems”; one in three adult Americans (about 78 million) having the condition. The World Health Organization and other medical organizations say high blood pressure poses the greatest risk for disease and death.
Blood pressure is measured as a ratio of systolic pressure — the pressure in arteries when the heart beats (or heart muscle contracts) — over diastolic pressure, which is arterial pressure between heart beats, according to www.Heart.org
There’s evidence, however, that the risk of cardiovascular disease begins rising at 115/80, said Jackson Wright, who led one of five research networks in the SPRINT study at the University Hospitals Case Medical Center in Cleveland.
“It’s very clear that relaxing treatment for blood pressure control over age 60 no longer is appropriate,” Wright said, noting the average trial participant age was 68.
If SPRINT findings hold up, guideline targets should be lowered, he said.
SPRINT begs the question of whether patients and doctors should take immediate action to reduce blood pressure or await study details.
“This will prompt discussion for all patients over 50 with high blood pressure who don’t only have hypertension, but a high risk of cardiovascular disease, chronic kidney disease or past cardiovascular events,” said Molly B. Conroy, an associate professor of medicine and epidemiology at Pitt. “What this will cause me to do with patients with high blood pressure is to make them aware of the new impact treatment can have and start a discussion of whether intensifying medication would be appropriate,” she said.