Isolated Diastolic Hypertension
Channel: York Cardiology
Date: 2023-11-25

A patient recently contacted me for some advice. Over the past few weeks, whenever he had his blood pressure measured by his doctor, his top number (the systolic pressure) was normal at 120 mmHg but his lower number (the diastolic pressure) was elevated at 95mmHg. His doctor was now pressurising him to take medications to lower his diastolic pressure. My patient was unkeen to take medications but felt like he was being forced into a corner. He therefore wanted my advice on the matter. This situation where the top number is acceptable to the medical fraternity but the bottom number is unacceptably high is called isolated diastolic hypertension. Here is what i explained to him.

Elevated blood pressure numbers are only important for 2 reasons.

1. The numbers are a symptom of some kind of underlying potentially harmful process such as premature aging of our blood vessels or excessive inflammation in which case you want to look for the underlying cause and treat the underlying cause usually by better lifestyle modification. In this situation giving tablets may be harmful because you are in essence silencing a scream for help

Or

2. The numbers themselves are doing us harm by being high in which case it makes sense to lower the numbers through a combination of lifestyle changes and medications

By wanting to give my patient medications their doctor had already decided that the number itself was doing the patient harm and this is why they wanted to reduce it. 

Let’s think of how blood pressure numbers could cause harm. 

Imagine blowing air into a balloon. If the pressure in the balloon is too high, 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 i.e the systolic is acceptable then they are saying that the top number is unlikely to be causing the patient harm. It therefore would not make any sense at all to say that the lower number is causing the patient harm. Surely if a pressure of 120 (the systolic) is not causing harm to the balloon then why on earth would a pressure of 95 cause harm? This is why there is absolutely no sense in treating isolated diastolic hypertension with pills. 

Isolated diastolic hypertension may be a symptom of more wear and tear etc of our blood vessels and therefore should encourage us to work on our lifestyles but isolated diastolic hypertension in itself does not usually cause damage and therefore does not need treatment with tablets. In fact most studies that have looked at this suggest that by aggressively lowering the diastolic number with pills you end up causing more side effects and possible harm than good.

So in this situation my advice to my patient was to work on the lifestyle rather than allow the doctor to give him unnecessary pills.

I would always advise that you speak with your usual healthcare professional and take their advice on your own situation before making any changes to your treatment plan/regime.