Minimum BP threshold to be included in guidelines
By Nigel Praities
Lower blood pressure thresholds look set to be added to guidelines for the first time after two major studies showed cardiovascular events start to rise again fairly soon after targets are passed.
In a major change to established practice, the European Society of Hypertension has announced it is to introduce a lower threshold for blood pressure – possibly around 120/70 mmHg – in its guidelines due for publication by the end of the year.
The announcement follows an analysis of data from the TNT study released last month showing a ‘J-shaped' curve for blood pressure in patients with coronary heart disease when plotted against the risk of major cardiovascular events or mortality.
Despite some cardiologists dismissing the research as being ‘completely misleading', the finding has subsequently been confirmed in data from two different studies presented at the European Meeting on Hypertension in Milan earlier this month.
Data from 9,600 patients with diabetes in the ONTARGET study showed that bringing blood pressure below 130/80 mmHg resulted in an increased risk of myocardial infarction if they had additional coronary risk factors.
Presenting the data, Professor Josep Redon, lead author and professor of medicine at the University of Valencia, Spain, said the data suggest that lowering pressures to much below 130/80 has benefits in patients with diabetes who are at increased risk of stroke.
But he added: ‘If your patient has more risk of coronary disease you have to be very careful of this, and you should keep the blood pressure not too low,' he said.
Another prospective trial presented at the meeting was conducted in 15,200 high-risk hypertensive patients – half of whom had a history of coronary heart disease – and found blood pressures of below 110/70 mmHg were associated with an increased risk of myocardial infarction, but not stroke.
Dr Giuseppe Mancia, chair of the ESH educational committee and professor of medicine at the University of Milan, Italy, said it was ‘mandatory' to include a lower threshold value in the upcoming guidelines from the ESH and suggested the limit would be around 120/70 mmHg.
‘Recommended blood pressure targets are changing because, as documented by two international trials, the old dogma of "the lower the blood pressure, the better" has been revised,' he said.
Dr John Ashcroft, CHD lead for Erewash PCT and a GP in Ilkeston, Derbyshire, said he would welcome a lower threshold being introduced to UK guidelines.
‘I often see patients with really quite low diastolics because they are trying to hit the targets, with no evidence that this is good. Particularly in elderly patients, they have a wide pulse pressure, which is not good,' he said.Evidence builds for J-shaped curve
BP below 130/80 mmHg increases risk of MI in diabetes patients if they have additional CV risk factors
MI risk increased below 76 mmHg diastolic and stroke below 60 mmHg in a population of high-risk patients with hypertension both with and without coronary heart disease
Lowest rates of major cardiovascular events seen at systolic BP of 139.9mmHg and diastolic BP of 79.2mmHg in patients with established coronary heart disease