NEW YORK -- Are automated office blood pressure measurements the way to go for routine check-ups?
Yes, argues , a cardiologist and researcher at the Sunnybrook Health Sciences Center in Toronto.
Myers has been a member of the European Society of Hypertension Working Party on Blood Pressure Measurement and contributed to national and international guidelines committees for blood pressure measurement.
What follows is an edited version of his conversation with 51˶ at the here, where he presented a lecture on automated blood pressure measurement.
What's wrong with the standard blood pressure cuff in the physicians' office?
Myers: "There's a myth that manual blood pressure -- blood pressure taken with a mercury device and stethoscope -- is accurate in the real world. The overwhelming evidence that in routine clinical practice doctors and nurses don't take manual blood pressure in the office with the same care according to guidelines as has been done in research studies with the result that the studies have shown that on average the blood pressure is about 10/5 mm Hg higher. So if we really wanted to look at what the cutpoint for hypertension in the real world in clinical practice is, it would be 150/95 not 140/90 just because it has been taken so poorly."
Is it just a matter of improving technique?
Myers: "The American Heart Association has tried for 5 decades to teach nurses and doctors how to take blood pressure properly. They know how to do it; they just often don't it in busy clinical settings all the time certainly, and often don't do it. Shifting the paradigm to get away from it, what we and others have discovered is that you have to eliminate the human element if you want to get an accurate assessment of blood pressure. The best way of assessing someone's status is the 24-hour blood pressure recording and that involves minimal human involvement. That's the perfect way. But in the office, the way to get around human error, bias, conversation between the observer and patient, and minimize patient anxiety is to use a fully automated device so the patient is alone and it takes multiple readings."
If 24-hour ambulatory blood pressure measurements are the best, why not use that?
Myers: The best way of diagnosing hypertension for virtually all of the guidelines is 24-hour ambulatory. Ambulatory is the best. What automated office blood pressure does is it offers the possibility of still doing the pressure in the office, because some experts have seriously written that office blood pressure is so bad we shouldn't be doing it anymore. If the automated office blood pressure does away with the white coat. It's much more accurate and reliable than any other technique in the office. It offers a way of maintaining office blood pressure to follow patients but not to diagnose patients. You really still should be using 24 hour to make a diagnosis and then you can go and monitor. You can't keep offering 24-hour blood pressures to see if they're responding and what they are 3 months from now. It's not really feasible."
What would be required to really shift U.S. practice beyond the few academic centers using automated systems?
Myers: "The there have been no guidelines recommending automated measurement until this past year. The American Society of Hypertension in their together with the International Society of Hypertension recommended electronic devices, not to use the mercury sphygmomanometer. The U.S. Preventive Services Task Force has recommended not making a diagnosis based on office readings because they're talking about manual office readings. They said use ambulatory blood pressure, which I agree with. I advised the task force and that was a task force for diagnosis. Unfortunately, the studies that used [the most studied of the automated blood pressure machines] that might have been useful for diagnosis were in already treated patients. They were classifying status as normal or not but they were not untreated.
"We have a paper which we have just sent out for publication that should change things in that it involves over 3,000 community-dwelling subjects with almost 300 endpoints over 5 years, which will give us the cutpoint at which automated blood pressure significantly increases risk. Right now we have 135/85 as the cutpoint because we've got lots of studies comparing the equivalent automated office pressure with the awake ambulatory or home blood pressure that they are the same. The Canadian guidelines have used that figure for 4 years now. What have now are some clinical outcome data to substantiate that cutpoint.
"That should have an impact on the guidelines from here on."
Disclosures
Myers disclosed no relationships with industry relevant to blood pressure measurement.