I’m a cardiologist from the UK. Today the subject of isolated diastolic hypertension. Now, let’s get started.
A few weeks ago, a patient contacted me for some advice. Over the past few weeks, he had been having his blood pressure checked with his GP. What the GP had found was that consistently the top number, the systolic blood pressure, was very acceptable.
So, his systolic blood pressure averaged around 120, and the GP said this is fine. But what had been concerning the GP is that the patient’s diastolic number, the lower number, was creeping up.
The diastolic pressure was now around about 95 mm of mercury. So, the GP had told my patient that he was concerned that the bottom number was beginning to creep up and he was beginning to pressurize my patient to start taking medications to lower the diastolic number.
My patient was very unkeen to take medications.
One, he didn’t really like the idea of taking pharmaceutical agents if they weren’t absolutely necessary, and he felt well in himself. Therefore, he almost felt cornered that he was being asked to take medications on the basis of this number going up, even though he felt well.
Whenever he would ask his doctor, the doctor would just say, ‘Look, you need to just get on these tablets. Listen to me, I’m your doctor, don’t argue, just take the tablets.’ My patient felt very uncomfortable with this, and that’s why he came to see me.
So, this is what I told him. He wanted my advice on the matter. This situation, where the top pressure number is acceptable to the medical fraternity, but the bottom number is unacceptably high, this is called isolated diastolic hypertension. The top number, systolic, is okay, but the diastolic is high.
So, I’m going to try and explain diastolic hypertension to you, and then I’ll tell you what this guy should have done. Okay, so the first thing is, if you think about it, elevated blood pressure numbers are only important for two reasons.
One, the numbers are a symptom of some kind of underlying potentially harmful process, such as premature aging of our blood vessels or excessive inflammation of our blood vessels. In which case, what you want to do is look for the underlying cause and treat the underlying cause, usually by better lifestyle modification.
In this situation, if that were the case, then giving tablets is actually doing the patient a disservice because you are silencing a scream. If something is a symptom, then you don’t want to treat the symptom; you want to treat the underlying process. The symptom is telling you there’s a problem, so you don’t want to just silence that scream
But there is another possibility that the numbers could, in themselves, be doing the patient some kind of harm by being high. In which case, it makes complete sense to want to lower the numbers, so if the numbers themselves are harming the patient, then you do want to lower the numbers as aggressively as possible, either with lifestyle changes or with, and with, medication.
But you see, by wanting to give my patient medications, that doctor had already decided that in this situation, the number itself was going to be doing the patient harm, and this is the only reason they would want to reduce it.
They would want to reduce it because they were feeling that the diastolic number, by going high, was going to cause the patient some kind of harm.
Now, let’s think of how blood pressure numbers cause harm. Imagine blowing air into a balloon. If the pressure in the balloon is too high, then the balloon will burst. If the pressure in our blood vessels is too high, then our blood vessels will get damaged.
But if the doctor is saying that the top number is acceptable, then what they’re saying is that I don’t think your top number is going to be causing you harm. Well, in that case, then it would not make any sense for the lower number, the diastolic, which is always less than the systolic, creeping up a little bit. It would not make sense that that number would now start causing the patient harm.
What I’m trying to say is that if your balloon is not going to burst when it has a pressure of 120, the systolic pressure in it, then why do we expect it to burst when it’s only got a pressure of 95 in it? And this is why there is absolutely no sense in treating isolated diastolic hypertension with pills because the lower number doesn’t actually cause you harm.
The lower number is a symptom; it tells you about what is going on in your blood vessels, but it is not a number that you want to reduce by giving the patient tablets.
So, when the diastolic number is high, it may be a symptom of more wear and tear of our blood vessels, and therefore, it should encourage us to work on our lifestyles. Because when we work on our lifestyles, we’re working on the underlying process. But isolated diastolic hypertension itself does not cause damage, and therefore, does not need treatment with tablets. In most studies that looked at this, when you try and aggressively lower diastolic numbers, actually, you end up causing more side effects and possible harm rather than good.
To my patient, I said, ‘Look, your diastolic pressure is telling you that your body’s unhappy. You need to work on your lifestyle, but you definitely don’t need tablets to lower your diastolic number.’