THE IMPORTANCE AND RELEVANCE OF INTERARM BP

An interesting paper was published in the online edition of Lancet on 30th Jan 2012, senior author Dr Christopher Clark of University of Exeter. It was also presented at the ongoing European Society of Hypertension. Of course it was picked up by BBC news and so it becomes a public discussion. What are the facts?.
Dr Clark and colleague identified 28 papers, all published before 2011, that had examined the patient survivals when both arms BP were taken. This is essentially a meta-analysis then. Of the 28 studies, they chose 20 to base their analysis on. They found that a systolic BP difference in both arms of >10 mmHg was associated with a significant risk of coronary heart disease. If put that way, it makes sense. Under the same condition ( which is never possible, except for intra-arterial monitoring, and this was only available in 5 studies which used invasive BP. However, if there is a > 10 mmHg difference in each arm, then it seemed to relate to some arterial disease, like primary arteritis ( or Takayashu's disease ) and subclavian artery stenosis. These conditions is associated with hypertension and so coronary artery disease.
However, the view put forward over bbcnews seemed to be that we should always have bilateral BP checked, as a BP difference in both arms, may mean a higher likelihood of heart disease and so, of dying. That is not quite what the article said.
It is not uncommon that when doctors take BP from both arms, as there will be a time lag, be it 1-2 mins, the BP may differ, particularly the systolic BP which is very prone to anxiety and situations. If we are not careful then, we will frighten a lot of people and lead to many more unnecessary investigations. Nowadays, ( and we encourage ), there are many households that monitor their own BP. You can imagine the panic that this bbcnews can cause, if not taken in the proper context.
I was very surprised, that a good medical journal like Lancet, would except such an article, which such a wide ranging title. It can easily be misunderstood. If their intention is that doctors should always bear in mind that patients may suffer from peripheral arterial disease which is a risk factor for CAD, then it is fair enough. I dare say that almost no doctor, will routine take BP in both arms, even now. We will check both arm BP if we suspect that the patient may have some form of peripheral arterial disease.
Anyway, I suppose a timely reminder that when we check BP, we should be mindful and have a high index of suspicion of the presence of peripheral arterial disease, is fair enough, especially when the patient's BP seem resistant to treatment.
It is good to monitor your own BP, especially males above 40 years and females above 50 years. Check it regularly, say twice or thrice a week, always at the same time and under the same conditions, after 5-10 mins rest. For BP monitoring, never check as a reaction to some fear of hypertension, as fear itself could raise BP, in seconds too. It will then be reactionary, and produce a circle of hypertension. Tension begats tension.
Take care. GONG XI FA CAI. WAN XI RU YI.