Bryan Williams, Professor and Chair of Medicine, University College London, UK, talks to Cardio Debate about the guidelines of high blood pressure treatment, how they compare in different countries, and the recent debate about high pressure goals.
Guidelines and goal blood pressure in patients with cardiovascular disease: What is your recommendation regarding goals to achieve?
There has been a lot of debate about how low we should lower blood pressure. I think the thing that’s clear is the conventional target across most guidelines in the world is less than 140/90 mm Hg. So we try and get everyone’s blood pressure on treatment below 140/90 mm Hg.
The only caveat to that is people who are over the age of 80 years, who have recently started treatment and in whom it might be difficult to get it down to those levels. And the best evidence we have is that we should target those to be below 150 systolic.
So 150 systolic, get below that over the age of 80 years. Less than 140 systolic over 90 for everybody else.
Now recently there was a publication, a big study from the United States called SPRINT, which targeted half the population in the study to a blood pressure below 120. And they showed a very significant reduction in mortality associated with cardiovascular disease, and even total mortality. So this has really fuelled the debate over whether we should be thinking about going even lower than 140 as our target for the treatment of hypertension.
Now before we jump to that conclusion we have to look at the SPRINT trial, and the kind of patients that went into that trial, and whether or not the result is generally applicable to the entire population or whether it really reflects a recommendation for a sub-population.
So the people in SPRINT had a high risk, they either had cardiovascular disease or chronic kidney disease, or they were over the age of 75 years. They did exclude people with diabetes and patients with a previous stroke, so that’s the first thing.
And secondly, many of the patients who went into the trial didn’t have particularly high blood pressure, so it wasn’t particularly difficult to get down to those targets.
So you can imagine if you see a patient in your typical clinical with a blood pressure of around 170, the idea, if they were 70 years old, trying to get them to below 120 – we all know that practically that would be quite challenging and technically quite difficult.
The other thing in SPRINT is that there was a significant increased risk of developing some side effects, hypotension, dizziness, renal impairment associated with the lower targets. So it didn’t come free – there was an offset in this trial.
So I think the data has stimulated debate, I don’t think it’s a definitive outcome. How do I interpret it in my practice? What I tend to do is I get everyone below 140. Then if I’m dealing with a patient who is quite high risk for cardiovascular disease – previously had a stroke, previously had a myocardial infarction, I will say to that patient ‘If you’re feeling okay at 135, we could try and go a bit lower. And it’s possible, if you tolerate that treatment, that you’ll get some added value from that.”
So I think what SPRINT has done is given justification to doctors to think about being more aggressive in patients who tolerate lower blood pressures than the conventional target, but we need to monitor them closely to make sure that they are tolerating this, and they are not running into any problems.
Should there be the same target blood pressure for everybody?
So the thing I often get asked about is, is it the same target for everybody? If you look at the current guidelines, actually they’ve relaxed the targets in diabetes, so less than 140/90 mm Hg is being broadly adopted as the same target for everybody. But I think there are patients who have got, maybe, albuminuria and progressive nephropathy in diabetes, patients who have recently had a stroke – particularly a haemorrhagic stroke – where it makes a lot of sense to get the blood pressure as low as the patient will tolerate, because we do know that in those types of patients, good control of blood pressure, lower than the conventional target of less than 140 is associated with some degree of added protection. And I think SPRINT lends support to that view. So in the very high risk patient where the damage that is going to occur in the future is in part mediated by blood pressure, trying to get their blood pressure as low as possible would be valuable.
And I think there has been a lot of confusion in diabetes because of the ACCORD trial, which led to the relaxation of targets in diabetes because the assumption was that ACCORD didn’t show any benefit. Actually in the primary outcome that was true, but it did actually show a 40% reduction in the risk of stroke which was a secondary outcome.
I think if ACCORD had been a bigger trial they probably would have seen a benefit of the more aggressive targets in diabetes. So I think the general relaxation of blood pressure targets in diabetes has been, in my view, wrong, because there was already other data supporting the lower targets.
So my practice it to try to get people with diabetes to 130, if they will tolerate it. Obviously a bit more careful in patients with precarious renal function, or patients who get dizzy, or who don’t tolerate that type of blood pressure falling on treatment.
You can’t have a single target for everybody. You have to individualise therapy. You can have a conservative target for everybody, which is 140. But for going lower I think you need to individualise, use skill as a physician and talk to the patient about whether they are tolerating the treatment. And if they do, they’ll probably get benefit.