Messerli and Bangalore use a second figure to graphically illustrate the potential consequences of the differing guidelines.
Cardiovascular death rates thus may vary three-fold depending on what BP goal we choose.
This marked variation in treatment recommendation highlights that they
are not only an evaluation and interpretation of evidence in question, but also a judgment weighted by personal, regulatory, and organizational preferences that can vary from physician to physician within a country and across geographical regions.
Physicians and patients (hopefully through shared decision making) are going to have to do some thinking on their own.
Messerli and Bangalore quote Immanuel Kant in this regard:
Enlightenment is man’s emergence from his self-imposed nonage. Nonage is the inability to use one’s own understanding without another’s guidance. This nonage is self-imposed if its cause lies not in lack of understanding but in indecision and lack of courage to use one’s own mind without another’s guidance. Dare to know! (Sapere aude.) “Have the courage to use your own understanding,” is therefore the motto of the enlightenment.
As a 64 year old who has emerged from his nonage with hypertension, I have carefully examined the latest American hypertension guidelines especially in light of the SPRINT study and elected to add a third anti-hypertensive agent to get my average BP below 130/80. It’s worked for me with minimal side effects but I carefully monitor my BP.
If I notice any symptoms (light-headed, fatigued) suggesting hypotension associated with systolic BP <120 mm Hg I tweak my medical regimen to allow a higher BP.
Like all of my patients I would prefer to be on less medications, not more but when it comes to enlightenment about the effects of hypertension, it is now clear that lower is better for most of us in our sixties down to at least 130/80*.
Sapere Audaciously Yours,
*N.B. In the SPRINT study the BP was obtained using an automatic BP cuff after 5 minutes of rest with the patient unobserved and averaging 3 recordings one minute apart.
This “research grade BP” averages about 12 mm Hg less than a routine single clinic obtained BP (see here.)
The new ACC/AHA guidelines for High Blood Pressure were published late last year and they were in favor of using home blood pressure measurement to aid in the management of hypertension.
I was happy to hear this as I am constantly advising my hypertensive patients to buy a home BP cuff, measure their BP once when they get up and again 12 hours later and report the values to me after two weeks.
I have not spent a lot of time instructing them on exactly how to make the measurement but the new guidelines do specify in detail how this should be done:
• Remain still:
• Avoid smoking, caffeinated beverages, or exercise within 30 min before BP measurements.
• Ensure ≥5 min of quiet rest before BP measurements.
• Sit with back straight and supported (on a straight-backed dining chair, for example, rather than a sofa).
• Sit with feet flat on the floor and legs uncrossed.
• Keep arm supported on a flat surface (such as a table), with the upper arm at heart level.
• Bottom of the cuff should be placed directly above the antecubital fossa (bend of the elbow).
• Take at least 2 readings 1 min apart in morning before taking medications and in evening before supper. Optimally, measure and record BP daily. Ideally, obtain weekly BP readings beginning 2 weeks after a change in the treatment regimen and during the week before a clinic visit.
• Record all readings accurately:
• Monitors with built-in memory should be brought to all clinic appointments.
I monitor my own BP at home and often wonder whether there is scientific evidence to support such a rigid protocol. Being a contrarian and a skeptic, I typically violate 3/4 of the recommendations that are listed.
It seems like all of the instructions are guaranteed to give you the lowest BP you are likely to experience during the day. The vast majority of the time I am not sitting quietly with my legs uncrossed, my bladder empty and my back straight so following these directions will underestimate my average daily BP.
I’ve spent some time looking into all the instructions and they generally have some scientific studies to support them. For example, the position of the upper arm in relation to the heart does heavily influence BP readings (more on that in subsequent posts.)
The Mandate To Uncross The Legs
The instruction that most intrigued me was this one:
Sit with feet flat on the floor and legs uncrossed.
A number of questions came to the skeptical hypertensive:
What if you are on an exam table and your feet don’t reach the ground?
Does it really make a difference if your feet are flat on the ground versus slightly crooked?
Does any degree of leg crossing influence BP? Legs crossed at the ankles? Legs crossed at the knee?
And once I began thinking of leg crossing I realized that I spend a lot of my time with my legs crossed. Was this raising my blood pressure and my cardiovascular risk? Did I cross my legs because I liked the feel of a higher blood pressure?
The ACC/AHA guidelines are not alone in this recommendation-take a look at the British Health Service recommendation:
3.5. Measurements should be taken in silence when the patient is relaxed, with both feet flat on the floor and their back and arm supported. Many patients automatically cross their legs, which raises their blood pressure, so it is particularly important to emphasise the need for the patient to uncross their legs when taking their blood pressure.
Apparently the Brits believe that any ambient sound will alter the blood pressure. Talking is right out!
But if talking, ambient sounds and crossing your legs raises your blood pressure shouldn’t we be advising patients to spend their days wearing ear plugs in silence with their legs uncrossed?
Scientific Studies On Leg Crossing
It turns out there are good studies showing that leg crossing raises your blood pressure.
The first was published in 1999 and involved 53 hypertensive and 50 normotensive subjects.
Participants were randomly assigned, using a cross over design to having seated blood pressures measured with their leg in three different postures
Feet flat on the floor and legs uncrossed
Legs crossed , method 1-popliteal fossa of the dominant leg over the suprapatellar bursa of the non-dominant leg.
Legs crossed, method 2- lateral malleolus (which the article spells mallelous) of the dominant leg over the suprapatellar bursa of the non-dominant leg.
I love the efforts these Calgarian investigators went to in this study to ensure blinding (although spelling is clearly not their forte’). They state “blood pressures were measured by one investigator who was behind a screen and blinded to the leg position of the patient while a second investighator (sic) ensured that the subject assumed the proper leg position.”
Systolic blood pressure in patients with hypertension increased by 8 mm Hg by method 1 leg crossing and 10 mm Hg by method 2.
Another study demonstrated that although crossing the legs at the knees influenced blood pressure, crossing them at the ankles had no effect.
If leg crossing raises the systolic blood pressure 8 to 10 mm Hg why aren’t we doctors recommending patients sit with leg uncrossed the majority of the time. Personally, I had never heard there were any health complications to sitting with my legs crossed.
Apparently the myriad health information sources on the internet are near unanimous in their condemnation of leg crossing but the hypertensive effect of this maneuver is usually not cited.
I must admit since doing this bit of research I have substantially reduced the amount of time I sit with my legs crossed. And I’ve pondered extensively whether sitting with legs crossed makes me feel any different and why I suddenly and seemingly randomly decide to cross my legs.
I’ve also started asking friends and colleagues and medical residents how much of the day they spend with legs crossed.
On teaching rounds one morning recently we tested a volunteer resident’s blood pressure with legs crossed and uncrossed. Sure enough, the systolic BP was 10 mm Hg higher with legs crossed.
For those of you itching to read more about BP and leg crossing here are the references:
Pinar R, Ataalkin S, Watson R. The effect of crossing legs on blood pressure in hypertensive patients. J Clin Nurs 2010; 19:1284–1288. [PubMed]
Adiyaman A, Tosun N, Elving LD, Deinum J, Lenders JWM, Thien T. The effect of crossing legs on blood pressure. Blood Press Monit 2007; 12:189–193. [PubMed]
Pinar R, Sabuncu N, Oksay A. Effects of crossed leg on blood pressure. Blood Press 2004; 13:252–254. [PubMed]
Avvampato CS. Effect of one leg crossed over the other at the knee on blood pressure in hypertensive patients. Nephrol Nurs J 2001; 28:325–328. [PubMed]
Keele-Smith R, Price-Daniel C. Effects of crossing legs on blood pressure measurement. Clin Nurs Res 2001; 10:202–213. [PubMed]
Foster-Fitzpatrick L, Ortiz A, Sibilano H, Marcantonio R, Braun LT. The effects of crossed leg on blood pressure measurement. Nurs Res 1999; 48:105–108. [PubMed]
Peters GL, Binder SK, Campbell NR. The effect of crossing legs on blood pressure: a randomized single-blind cross-over study. Blood Press Monit 1999; 4:97–101. [PubMed]
The skeptical cardiologist frequently has his hypertensive patients check their BPs at home and report the values to him.
An easy, accurate and efficient way to record BPs at home, and transmit to the doctor, is my Holy Grail for management of hypertension; QardioArm offers to improve on this process compared to more conventional home BP cuffs.
I recently bought a QardioArm for my father and tested one myself over the last month, and herein are my findings. I compared it closely to my prior “go to” BP device, the Omron 10 (which I recommended as a Christmas gift here).
The QardioArm looks like and is packaged like an Apple product. The box containing the device is esthetically pleasing, and can serve as an excellent storage and transportation mechanism. The case closes magnetically and has a pocket, within which resides the manual.
Upon removing the QardioArm, one is struck by how compact, sleek and cool it looks. This is not your father’s BP cuff. There are no wires or tubes coming off it, and the cuff wraps around a red (white, blue or gold) plastic rectangular cuboid.
The cuff/cuboid is small enough to easily fit in a purse or satchel, facilitating portability.
Ease of Use
Once you understand how the device works it is a breeze to use. However, if you are inclined, like me, to skip reading the instruction manual, you run the risk of being incredibly frustrated.
First, you must download the free Qardio App to your smartphone, create a user login, register and create your personal account. If you don’t have a smartphone or tablet or don’t use the internet, this cuff if not for you. For me, this was a simple, quick process.
After setting up the Qardio App, you pair the QardioArm with the App. This requires the QardioArm be on and Blue Tooth be enabled on your smartphone.
You might think that turning on the QardioArm, and knowing it is on,
would be an incredibly easy and obvious process: it is not (unless you pay close attention to the instructions). If you read reviews of Qardioarm on Consumer Reports or Amazon, you will encounter many very unhappy users. This is primarily because some folks could not get it to turn on.
Here are my detailed instructions for turning it on:
There is a small magnet inside the cuff.
The device turns itself on when you unwrap the cuff and it turns off when you wrap the cuff back up. (I am not good at wrapping things up properly and ran into issues initially because of this). When you wrap the cuff up properly you can feel the magnet locking into place and thus turning the device off.
When the device is on there is no light to indicate it is on. A green light flashes on the side when it turns on, but then goes out. Many user reviews indicate frustration with this and often they end up trying to change the batteries, believing that the device is dead. I went through this same thought process initially.
The device turns off “after a few minutes” if not used. You won’t know if it is on or off. If it doesn’t respond when you trigger it from the App, you must carefully rewrap the cuff and then unwrap it. If you don’t trigger the device properly with the magnet, it won’t wake up.
Now that you know how to turn the device on and have paired it with your Cardio App, put the cuff over your upper arm with the cuboid over the inner aspect of your arm,
hit the big green START button and sit back while the cuff is magically inflated and an oscillometric measurement of your blood pressure performed.
The blood pressure is displayed on the app instantaneously along with pulse. If the device detects irregularity of the pulse (a possible but not reliable sign of atrial fibrillation or other abnormal heart rhythms), it display an “irregular heart beat” warning.
You can have the QardioArm take 3 BPs, a variable amount of time apart, and average the readings.
BP and pulse data can be viewed in tabular or graphic formats and can be synched with the Apple Health App:
I found the QardioArm BP measurements to be very accurate. My medical assistant, Jenny, recorded our patient’s BPs using the “gold-standard” manual technique, and with QardioArm (consecutively and in the same arm), and there was excellent agreement. In one man with a very large arm, she could not record a BP (QardioArm’s cuff fits the arm of most people, and is appropriate for use by adults with an upper arm size between 22 and 37 cm (8.7 and 14.6 inches). If your upper arm is larger than that, this device is not for you. In one patient who was in atrial fibrillation, the device properly recorded an “irregular heart beat.”
From the Qardio website:
QardioArm is a highly accurate blood pressure monitor and has undergone independent, formal clinical validation according to ANSI/AAMI/ISO 81060-1:2007, ANSI/AAMI/ISO 81060-2:2009, ANSI/AAMI/IEC 80601-2-30:2009, as well as British Standard EN 1060-4:2004.
QardioArm is a regulated medical device: FDA cleared, European CE marked and Canadian CE marked.
It measures blood pressure with a resolution of 1 mmHg and pulse with 1 beat/min.
The accuracy is +/- 3 mmHg or 2% of readout value for blood pressure, and +/- 5% of readout value for pulse.
Comparison To Omron 10
I spent time evaluating the accuracy of QardioArm because a few online reviewers suggest that it is highly inaccurate for them and Consumer Reports gives it a “poor” rating for accuracy.
I compared it to the Omron 10 (Consumer Reports highest-rated BP device), and found close agreement between the two.
I took my own BP with the QardioArm on the left arm and the Omron 10 on the right arm. Multiple simultaneous measurements showed less than 3 mmHg difference in systolic blood pressure between the two.
Unlike Consumer Reports, I found QardioArm superior to the Omron 10 in several areas:
QardioArm is faster. It took 30 seconds to complete a BP measurement, compared to 50 seconds for the Omron 10.
BPs are immediately available on my iPhone with QardioArm, whereas a separate Bluetooth synching process is required for the Omron App. This process never works well for me, as the Omron fails to transmit measurements reliably.
It is amazingly easy to transmit BPs via email to your doctor (or friends if so inclined).
I found the QardioArm website to be very informative and helpful. The manual that comes with the device is very complete and you should definitely read it before using the device. I did not need telephone or email support services, so I can’t comment on those.
Overall Rating and a Caveat
Despite an initial frustration with QardioArm, I ended up really liking this device a lot. This sounds a little silly but the QardioArm improved the esthetic experience of home BP monitoring for me. Because it is compact, sleek and attractive, patients may be more likely to utilize it on a regular basis. In particular, I see it as something that you would be much more inclined to take with you for BP monitoring at work or on vacation.
I will be recommending this to my tech-savvy, style-conscious patients who require home BP monitoring. Previously, this type of patient would bring in their smartphone and show me the accumulated data from their BP readings. With a QardioArm, they can easily email my office the data and we can have it scanned into their record.
My final caveat: the QardioArm I gave my father for his 91st birthday does not work on his arm. It works without a problem on the arms of his friends and relatives. I have no idea why, but fortunately QardioArm honored their 30 day 100% money-back no questions asked guarantee. I’ve asked him to give me his nonagenarian perspective on the QardioArm experience so I can share it in a future post.
The skeptical cardiologist was shocked to hear that there was a smartphone app which he had heretofore been unaware of that claimed to measure blood pressure.
Made by Aura Life and named Instant Blood Pressure, the app was apparently selling like hotcakes on the Apple app store until it was abruptly removed in 2015.
Users are instructed to put the top edge of the smartphone on the left side of the chest while placing the right index finger over the smartphone’s camera
Since it was created by “a team of forward-thinking biomedical engineers and software developers” and is to be used to measure one’s blood pressure one might be fooled into thinking that it might accurately measure blood pressure. Don’t be silly!
The IBP web site clearly states:
“Instant Blood Pressure is intended for recreational use only. It is not a replacement or substitute for a cuff or other blood pressure monitor. Instant Blood Pressure’s performance and accuracy characteristics do not meet international standards for a blood pressure monitor intended for clinical use.”
How does one use a blood pressure device that is not really intended to measure blood pressure for recreational use? Beats me.
A research letter in JAMA Internal Medicine reports that the app is really inaccurate: 77% of patients with hypertensive blood pressure levels were assured that their blood pressure was in the nonhypertensive range.
The authors note:
Between its release on June 5, 2014, and removal on July 30, 2015 (421 days), the IBP app spent 156 days as one of the top 50 best-selling iPhone apps; at least 950 copies of this $4.99 app were sold on each of those days.2Validation of this popular app or any of the similar iPhone apps still available (eg, Blood Pressure Pocket, Quick Blood Pressure Measure and Monitor), have not been performed.
Don’t rely on any smartphone app to accurately measure your blood pressure. None of them have been validated and they are being promoted by charlatans looking for a quick buck off naive consumers.
Excuse me while I check my BP with my Omron 10 real BP monitor. I think it might be really high now.
As December draws ever closer to the twenty-fifth you may find yourself behind the wheel of a large automobile puzzling over the perfect gift for your loved ones.
Fear not, for the skeptical cardiologist has a few suggestions to help you.
The Omron 10 Blood Pressure Monitor
If your hypertensive friend or relative already has all the standard BP paraphernalia (pill splitter, basic BP cuff), owns a smart phone and has an engineer or scientist approach to data the Omron 10 (BP786, 59.99$ at Best buy.com) just might be the perfect gift.
The skeptical cardiologist recently purchased two (that’s right two) of these in anticipation of Christmas.
Christmas arrives with multiple stressors guaranteed to hike your blood pressure.
The Omron 10 offered three features not available on my basic Walgreen’s BP cuff that I felt were possibly useful:
Averaging/automating three consecutive readings. After reading about the SPRINT BP trial which showed a benefit of aiming for SBP of 120 over 140, I thought I should try to reproduce the method used in the trial. This involved measuring BP 3 times separated by 5 minutes and averaging the results. The Omron 10 can be set to make and average three BP readings separated by a variable time period.
The ability to communicate with an iPhone or Android smartphone and record and display the data in an app.
Works off both batteries and plug in electrical power.
I thought my dad (a retired chemist) would like the Omron 10’s features but, alas, he informed me that if he wanted to average three BP readings he could just write down the numbers and do the math.
If he had an iPhone he might really like the way the Omron sends its data to the free Omron app.
The app displays BP and heart rate readings recorded for different time intervals.
You can take a screen shot like I did here or email it and share the data with your doctor through the doctor’s patient portal!
I’ve mentioned this really cool device a few times (here and here).
It is now listed on Amazon.com for $57 (a significant drop from when I purchased it) and can be attached to your smartphone case. It does a really good job of recording a single lead electrocardiogram (ECG) and diagnosing normality or atrial fibrillation.
If your friend or loved one is experiencing periodic fluttering in their chest or a sensation of the heart skipping beats or racing (the general term for which is palpitations) then this could be the perfect gift.
A number of my patients have purchased these and have made ECG recordings which I can review online.
Primarily I have been recommending them to my patients who have atrial fibrillation periodically.
You may think this is too complicated a device to master but last week I saw in my office a 94 year old lady who had had an episode of atrial fibrillation earlier in the year. Since her last visit she had purchased an AliveCor device and was able to show me the ECG recordings she had made on her iPhone.
May your holiday season be joyous, full of loved ones and free of stressors that raise your blood pressure and cause your heart to pound and race. But if it is not, consider purchasing one of these nifty devices.
Would you rather have a systolic blood pressure (BP) of 120 mm Hg or 140 mm Hg?
Prior to a week ago this sometimes skeptical cardiologist thought treating hypertensive patients to the lower BP didn’t necessarily help avoid death from cardiovascular disease, heart attacks or strokes and that it resulted in more side effects.
Clinical trials have shown that treatment of hypertension reduces the risk of cardiovascular disease outcomes, including stroke (by 35 to 40%), heart attacks (by 15 to 25%), and heart failure (by up to 64%) but the target for systolic blood-pressure lowering has been uncertain.
The SPRINT trial randomized almost ten thousand patients and compared the effects of antihypertensive treatment with a systolic blood pressure (SBP) target of <120 mm Hg (intensive treatment) versus <140 mm Hg (standard treatment).
They studied hypertensive adults ≥50 years of age who had an average SBP of 130–180 mm Hg (the acceptable upper limit decreasing as the number of pretrial antihypertensive medications increased) and were at additional risk for cardiovascular disease (CVD).SPRINT was designed to recruit study participants with an average CVD risk of ≈2% per year, equivalent to a Framingham 10-year CVD risk score of 20%.
To understand if these trial results apply to you it is important to know what patients were enrolled in the study (inclusion and exclusion criteria) and I’ve listed these at the end of this post.
The SPRINT trial found that cardiovascular events like stroke and heart attack and death from these cardiovascular causes was lower by 25% in those patients treated intensively. Overall death was lower by 27%
Average systolic blood pressure was 121 mm HG in the intensive therapy group and 134 mm Hg in the standard therapy group.
Drugs used were: thiazide-type diuretics, calcium channels blockers, and angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. Other agents, including spironolactone, amiloride, β-blockers, vasodilators, or α-receptor blockers, could be added if necessary. On average, 2.8 drugs were used in the lower BP group versus 1.8 in the higher BP group.
This more intensive BP treatment was surprisingly well tolerated. Very surprisingly, orthostatic hypotension, (drop in BP on standing I talked about in my post on burpees and dizziness) was significantly more common in the standard than in the intensive arm. I would have expected this opposite.
There were significantly more kidney problems and electrolyte abnormalities in the intensive group compared to the standard therapy group.
This study provides a very powerful argument for shooting for a BP of 120 in many of my patients.
It’s important to replicate how BP was measured in the SPRINT trial if we are to apply the results. As the authors have written elsewhere:
“be mindful of the manner in which BP was measured in the trial: an average of 3 office BP readings taken with proper cuff size, participants seated with their back supported, 5 minutes of rest before measurement, and no conversation during the rest period or BP determinations. In SPRINT, this was achieved using an automated manometer (Omron Healthcare, Lake Forest, IL) that was preset to wait for 5 minutes before measurement, as well as to take and average the 3 readings. BP measurements taken without observing these conditions are likely to overestimate BP6 and result in over treatment, with the potential for higher rates of serious adverse effects and greater utilization of resources.”
And the entry criteria:
Increased cardiovascular risk was defined by one or more of the following: clinical or subclinical cardiovascular disease other than stroke; chronic kidney disease, excluding polycystic kidney disease, with an estimated glomerular filtration rate (eGFR) of 20 to less than 60 ml per minute per 1.73 m2 of body-surface area, calculated with the use of the four-variable Modification of Diet in Renal Disease equation; a 10-year risk of cardiovascular disease of 15% or greater on the basis of the Framingham risk score; or an age of 75 years or older. Patients with diabetes mellitus or prior stroke were excluded