New research suggests that doctors should not only check for high blood pressure, but also monitor changes at each visit.
A British study with more than a million measurements found that variability in blood pressure is an important predictor of the risk of heart attacks and strokes.
Patients with fluctuating levels may be at greater risk of a ‘cardiovascular event’ than patients with high but stable blood pressure, which is controlled with medication.
Experts say the findings should be taken up by health professionals to identify and treat patients most at risk.
Imperial College Researchers followed more than 8,000 British patients with high blood pressure for over 20 years.
A British study with more than a million measurements found that variability in blood pressure is an important predictor of the risk of heart attacks and strokes. Patients with fluctuating levels may be at greater risk of a ‘cardiovascular event’ than patients with high but stable blood pressure, which is controlled with medication
They found that variation in systolic pressure – the top number that represents the pressure as your heart pushes blood out – over time was a strong predictor of stroke, heart attack and atrial fibrillation.
This was the case even in patients whose blood pressure readings were within a healthy range but varied between visits, according to results published today in the European Heart Journal.
Blood pressure can vary throughout the day, but the impact of blood pressure variability over the longer term is less clear.
Half of the participants, the majority of whom were men with an average age of 64, were taking a calcium channel blocker, amlodipine, to control their high blood pressure.
They were then divided into thirds based on their mean systolic blood pressure and their blood pressure variability.
Among patients with an average systolic blood pressure of less than 140 mmHg – borderline high blood pressure – those with the highest variability had a 16 percent greater risk of heart attacks, strokes and other cardiovascular events compared to the group with the lowest variability.
It also showed that more than half (53 percent) of events occurred in patients whose blood pressure was well controlled on medication – below 140 mmHg – suggesting that the threshold and treatment are inadequate.
Excessive heart attacks and strokes were still seen in people with levels of 130-135 mmHg, the Pfizer-funded study found.
Researchers said the findings indicate that systolic blood pressure variability of 13 mmHg or more over a five-year period may be associated with a significantly increased risk of cardiovascular events.
They also emphasize that data from the study shows that one blood pressure drug, a drug called amlodipine, was effective at lowering blood pressure variability and could help reduce the risk.
Nearly one in three British adults (30 percent) are thought to have high blood pressure, with cardiovascular disease responsible for 170,000 deaths a year, around one every three minutes.
Professor Peter Sever, from the National Heart & Lung Institute at Imperial College London, and senior author of the study, said: ‘We have long known that high blood pressure increases the risk of heart attacks and strokes.
‘But our latest findings also highlight the importance of monitoring variability in blood pressure over time.’
He added: ‘It is critical that international guidelines for physicians are updated to reflect these latest findings and to include blood pressure variability as a major risk factor for heart attack and stroke.’
Bryan Williams, Chief Scientific and Medical Officer at the British Heart Foundation, said: ‘These findings shed further light on the predictive significance of blood pressure variability for the risk of heart attack and stroke.
‘The study suggests that monitoring blood pressure variability could be an essential addition to routine health checks, helping to identify patients who remain at risk despite appearing to have well-controlled blood pressure.
‘The challenge identified by this research for the future is how we can reduce blood pressure variability and even out the blood pressure profile, beyond the reduction in blood pressure itself, which we know is protective against heart attack and stroke .
‘It is estimated that 30 per cent of adults in Britain have high blood pressure, which equates to around 16 million adults. Getting your blood pressure checked and treated if it is elevated is one of the most important things you can do to prevent heart attack and stroke and help save lives.”