All Blood Pressure Changes Should Be Monitored, Treated
Physicians have often dismissed occasional high blood pressure readings as insignificant, but new research from the University of Oxford suggests that even episodic hypertension or unstable blood pressure may put a patient at a higher risk of stroke.
Peter Rothwell MD and team conducted four studies that evaluated episodic or variable blood pressure. High blood pressure readings account for about 50% of stroke risk, according to background information. The articles were published in the medical journals Lancet and Lancet Neurology.
The first study monitored 2,000 people who had a previous transient ischemic attack (TIA), which is sometimes called a “mini-stroke”. Patients were assessed once every four months for a total of seven clinic visits. Those who had variable blood pressures had a risk of stroke six times greater than those with stable high blood pressure.
The research focused on the systolic blood pressure reading with reflects the pressure of the heart contractions while pumping blood. Normal systolic blood pressure is 120 or below. Some variability in blood pressure readings is normal, but when the systolic pressure fluctuated 40 mm/Hg or more, the risk of stroke became increased.
High blood pressure readings were also associated with a higher stroke risk. Those in the study with the highest blood pressure were 15 times more likely to have a stroke.
The second study tracked 8,000 patients who had had a heart attack, and researchers found the same association between variable blood pressure rates and stroke risk. The final two studies, Dr. Rothwell examined the data from 389 studies on the effects of different blood pressure drugs on the occasional spikes in blood pressure and found that most were also effective at preventing strokes.
"I think that the risk associations, and other evidence, are sufficiently strong for us to stop reassuring patients with variable blood pressure that they don't have hypertension and don't need treatment, which is what current guidelines argue if their [average] blood pressure is OK,'' Rothwell says. " We should be concerned about episodic hypertension in patients who are not on treatment and about residual variability in patients who are already on treatment."
He does suggest to patients not to rush to change their treatment of high blood pressure, but to monitor readings regularly and discuss the trends with their physicians. The American Heart Association recommends that patients with high blood pressure readings check rates at home as well as at a medical clinic.