Haemostatics: Stephen Hales and the first direct measurement of blood pressure

Blood pressure lowering medications are among some of the most effective and useful medications currently used in medicine. In 2017 the ACC/AHA released new guidance for the evaluation and management of high blood pressure in adults.1 This guidance outlines what is considered normal, elevated, and hypertension in adults.1 We now understand the great importance of blood pressure in health but this wasn’t always the case.

As far as we know, blood pressure was first mentioned by G. Harveo (1628) where he warned surgeons that blood could “jet out” of the artery.2 What I was interested in was the first measurement of blood pressure as we know it. That first measurement was done by Reverend Stephen Hales in 1733.2

I remember learning this during undergrad, and the image is striking. It is a picture of Hales and his associate with a horse laying on its side. They inserted a brass tube into the femoral artery connected to a glass tube running vertically out of the horse’s neck.3 The blood reached 8 feet 3 inches.4 Further work by Hales and others went on to describe blood pressures in different species and different vascular beds, but I haven’t been able to get the image of this horse out of my head.2




As my last post for the AHA Early Career Bloggers, I wanted to look into Stephen Hales. Who was he? Why did he do this experiment in the horse? And what else did he do? Hales was a Reverend in Middlesex who dabbled in many scientific pursuits. What I was interested in were those pertaining to the cardiovascular system. I went directly to the source: Statical Essays Containing Haemastatics.4

4 https://books.google.com/books?id=uDQ-AAAAcAAJ (eBook)

4 https://books.google.com/books?id=uDQ-AAAAcAAJ (eBook)


To get some context, this is what was thought about the cardiovascular system of arteries and veins at the time, “As an animal body consists not only of a wonderful texture of solid parts, but also of a large proportion of fluids, which are continually circulating and flowing, through and inimitable embroidery of blood vessels…it has, ever since the important discovery of the circulation of the blood, been looked upon as a matter well worth the inquiring into, to find the force and velocity with which these fluids are impelled…”4

This book doesn’t have any illustrations, unfortunately, but there are descriptions of the many experiments Hales performed. He repeated his experiment on pressures in the horse several times. In fact, the famous image of Hales with the horse was from his 3rd horse experiment. Eventually Hales started collecting the blood and determining how much there was in addition to pouring wax into the empty heart to make a cast and determine the chamber volumes. He compiled this into a pair of tables. 4

4 https://books.google.com/books?id=uDQ-AAAAcAAJ (eBook)


Based on Hales’ measures, he calculated that “a quantity [of blood] equal to the dog’s weight, will pass through the heart in 11.9 minutes”. You’ll notice that Hales made calculations for “Man” but these were derived from data from the other animals and he never performed these experiments on humans.4

Stephen Hales contributed to science in many ways including in other fields. He is famous for inventing a ventilator that circulated air in ships, prisons, and mines which likely saved many lives. Hales had no medical training. He obtained a bachelors degree in divinity and a Master of Arts. Hales is a reminder that great discoveries can be made by anyone with a curious mind.5

4 https://books.google.com/books?id=uDQ-AAAAcAAJ (eBook)

4 https://books.google.com/books?id=uDQ-AAAAcAAJ (eBook)


Don’t forget to register for #Hypertension19 happening this September 5-8 in New Orleans! 



  1. https://www.heart.org/-/media/data-import/downloadables/hypertension-guideline-highlights-flyer-ucm_497841.pdf
  2. The history of blood pressure measurement: from Hales to our days. V.A. Tsyrlin, M.G. Pliss, N.V. Kuzmenko. April 2016. Arterial Hypertension.
  3. http://www.epi.umn.edu/cvdepi/wp-content/uploads/2011/05/Hales-Horse.jpg (http://www.epi.umn.edu/cvdepi/essay/reverend-stephen-hales-on-blood-pressure/)
  4. Stephen Hales. Statical Essays Containing Haemastatics. (eBook: https://books.google.com/books?id=uDQ-AAAAcAAJ
  5. https://en.wikipedia.org/wiki/Stephen_Hales



Apple Watch, Fitbit or RESPeRATE – Can They Assist in Lowering Blood Pressure?

which device should I choose?

We see people walking around with the wearable devices everyday without regard to whether they really make a difference with metabolic parameters. These devices all have the capability of prompting wearers to take steps, stand up when sitting, but they can also alert wearer to slow breathing. A poster presented at Experimental Biology in Orlando by Evan D. Jette, a student from the Usselman’s lab at McGill University in Montreal, QC, Canada made the argument these wearable devices can potentially lower blood pressure (BP). I was interested in whether there was more research surrounding these wearable devices, especially Fitbit and Apple because I noticed they were prevalent among conference goers.

Evan’s research suggested there was a trend with blood pressure among clinical populations (high BP or T2DM) indicating that slower breathing (~15 breaths per min) can potentially have a positive impact on diastolic BP. He further indicated that the Fitbit may have been optimal in lowering BP via respiratory rate due to the ability of the Fitbit to customize breathing to the wearer rather than generating a standardized rate for all subjects. These data leave me to wonder, since the RESPeRATE is marketed to lower blood pressure by controlling breathing, and most people own wearable devices such as commercially available Fitbits or Apple Watches, would these devices really assist in BP modulation?

There is a significant amount of literature surrounding the heart rate capability of the wearable devices, but negligible data referencing changes in blood pressure. The exception is RESPeRATE taking the stand that their product is “clinically proven to lower blood pressure”. In the study by Jette, participants that undergo low to moderate exercise exhibited no significant difference in heart rate with either the Fitbit or the Apple Watch. However, under extreme conditions such as high impact training, accuracy was reduced across both devices. The Fitbit provided heart rates that were equivalent to the Polar monitor (a heart rate monitor strapped to the subject’s chest). I wonder under these experimental conditions will RESPeRATE have similar outcomes.

Nevertheless, I did not find any data that supporting these wearable devices playing a role in reduced BP. I think the Usselman’s group is on to something with exploring the use of these wearable devices to modulate BP. However, a healthy lifestyle that incorporate the AHA Life’s Simple 7 will assist in blood pressure reduction. So, keep wearing your fitness devices to maintain an enhanced level of motivation and stay connected to a community of people that will support your BP reduction goal.


Joint Hypertension 2018 Scientific Sessions – You Should Have Been There

hypertension 2018

Just as promised, the Joint Hypertension 2018 Scientific Sessions (Hypertension18) was indeed among the most impactful meetings one could have attended. Council on Hypertension Scientific Sessions Planning Committee Vice Chair Dr. Karen Griffin, FAHA was accurate in her statement that it would be “the premier scientific meeting.” There were experts from all parts of the world covering more cardiovascular topics that I think my fingers could not keep up with in note taking, and each session was more informative than the next with up-to-date information on hypertension.

During the President’s Welcome Address, Dr. Ivor Benjamin, FAHA foreshadowed what was to be expected during the meeting. He gave general overviews of the hypertension guidelines, what the changes mean to clinicians and researchers, as well as the role AHA will play in helping drive those changes forward. His welcome was a great introduction to the ‘Recent Advances in Hypertension’ Session chaired by Drs. Joey Granger from the University of Mississippi Medical Center and John Bisognano from University of Rochester Medical Center. This session covered the new guidelines, implementation, and basic research advances of clinical hypertension moving forward by Drs Basile, Egan, Oparil, and Ellison. The whirlwind of information was just the icebreaker! During the refreshment break and exhibits, I met a number of “Rockstars” including clinicians and researchers from University of Alabama Birmingham, Drs. David and Jennifer Pollock and AHA Early Career blogger Tanja Dudenbostel. Additionally, this was the only time I spent visiting with vendors. Among them, Hulu explained the importance of calibrating automatic blood pressure machines. Historically blood pressure was taken with a manual sphygmomanometer and a technician listening for ausculatory sounds via a stethoscope, but now it is all automated. Generally one machine is used for all patients. This technology forces us to question the accuracy of the readings of the machines. Are they calibrated? Should the BP be taken radially or at the wrist? Should the machine be changed throughout the day? There was Aegis representatives sharing information about products to assist medical professionals determine patient compliance to therapy and toxicology testing equipment. During these conversations, it was surprising to discover some of the rationales behind why people would opt to not take medicine as prescribed.

With my research being focused on oxidative stress-induced vascular injury and since I have become increasingly more interested in health and wellness, I took particular interest in the session focused on “Lifestyle Modifications and Impact on BP” chaired by the Associate Editor of Hypertension, David Harrison, MD, FACC, FAHA, “Recent Advances Obesity and Cardiovascular Disease” chaired by the consulting Editor of Hypertension Suzann Oparil, MD, FAHA, and “Obesity, Diabetes, and Metabolic Syndrome” chaired by Drs. Kamal Rahmouni and Carmen De Miguel. During these sessions, it was not surprising that regular exercise reduced vascular stiffness, but what was noteworthy was that weight training contributes to atherosclerosis. Additionally, the sympathetic nervous system seems to be important in glomerular filtration. Dr. Elizabeth Lambert delivered an intriguing talk about how diet and exercise can significantly decrease metabolic syndrome in middle aged obese individuals, which is consistent with a recent study (Hypertension18 Meeting Report P388) that suggests lifestyle changes can reduce hypertension in both men and women. Further, the study suggests that following the DASH diet, exercising, and weight management over a course of 16 weeks were contributing factors in reducing BP in test subjects. We all know anti-hypertensives work in reducing BP. Lifestyle changes should be the first line of defense in evading hypertension and getting it under control at the onset, according to the American Heart Association/American College of Cardiology  Hypertension Guidelines. We have all heard that we have to get out there and get moving. Choosing the right exercise is just as important as exercising, according to Dr. Tanaka.

I recently wrote a blog discussing metabolic syndrome and therein indicated there is not a direct correlation between obesity and diet. During this conference, Dr. John Hall lectured on the recent advances in CVD and obesity. He suggested that epigenetic transmission of obesity in humans (and others) is associated with increased adiposity and insulin resistance, depletion of nuclear protein, influence chromatin conformation, and altered germ cell methylation and gamete micro RNA.

The new concurrent session Clinical Practice Clinical Science and Primary Care tracks did not go unnoticed. Although I did not get to attend many of these sessions, I did pass them to see that they were well attended. I did attend some of the lunch meetings and they were very insightful. Please refer to my Twitter to see my detailed notes. As mentioned in my pre-conference blog, with all the sessions that were available one should not have had an issue meeting the goals outlined in the program by coordinators (infra vide). Several sessions that met the interest of all researchers/clinicians, early career, and everyone in between. Not a person that attended Hypertension18 could say they could not find a learning opportunity at the Joint Hypertension 2018 Scientific Sessions! Even if one was merely a passerby, there was a session relevant to them. For example, I was on my way to get coffee when I encountered Drs. Yagna Jarajapu from North Dakota State University and Daniel Batlle from University of Chicago discussing research concerning STZ diabetic Foxn1 mice that were ischemic for several days. Subsequently, Eric Metterhausen shared his mission of services (MOS, for you military people) with me as we conversed about field medicine with the United States Public Health Services (USPHS). I did know our US Armed Forces had research officers and divisions of research, but the amount of detail that Major Metterhausen described was a beast that I had not known. Conversations such as these lead to increased mentoring relationship, as well as potential collaborations in research and grant proposals. We all go to conferences to learn, to purchase new research equipment, and to present our data, but we also should not forget to network and build relationships.

Conference Learning Objectives:

  • Discuss changes to the AHA/ACC guidelines for the management of hypertension and their clinical implications.
  • Describe opportunities to improve blood pressure measurement in the clinical setting to provide more accurate results.
  • Identify immune and inflammatory mechanisms that contribute to the development of hypertension and hypertension-related end-organ damage and discuss the research and clinical implications.
  • Educate participants about medical approaches for the management of comorbid obesity in patients with hypertension.


  • Describe participants on the impact of value-based reimbursement on hypertension management and identify opportunities to improve its management.


See you all in Chicago at Scientific Sessions 2018!!!

  • Leave a comment and follow me on Twitter @AnberithaT and @AHAMeetings if you have questions or are interested in something else specifically.


Anberitha Matthews, PhD is a Postdoctoral Fellow at the University of Tennessee Health Science Center in Memphis TN. She is living a dream by researching vascular injury as it pertains to oxidative stress, volunteers with the Mississippi State University Alumni Association, serves as Chapter President and does consulting work with regard to scientific editing.


Eat smarter- How to boost your cardiovascular health and lower your blood pressure with functional foods – Watermelon

It’s finally summer. Warmer temperatures and local Farmer’s markets motivate us to eat lots of fresh fruits and greens. A healthy summer diet maintains our health and can be even supportive in the management of various diseases. For example, some patients with treated blood pressure are able to taper off blood pressure medications by eating not only healthier but also smarter, losing weight and exercising more.

American Heart Association guidelines recommend eating 9 servings of fresh fruit and vegetables per day. Although reasonable, it is often difficult to implement these recommendations into one’s busy life. In addition to consuming more fruits and greens, is it possible to eat smarter and implement more so-called functional foods to positively affect blood pressure and ultimately cardiovascular health?

One of my friends brought my attention to the beneficial effects of watermelon. Since then I am hooked. For me, watermelon in the form of juice works best – either in the office or during work outs to help with next day muscle soreness.

Watermelons are sweet and popular fruits of summer, originating from sub-Saharan Africa, usually consumed fresh in slices, diced in fruit salads, or as juice. They contain more than 90% of water and are low in fat. Against popular belief watermelons are neither high caloric nor do they have high sugar levels. They contain approximately 6-7 g total sugars which is half of total sugars found in apples, bananas, mangos, sweet cherries, kiwis, pineapples etc., and comparable to blackberries, blueberries, grapefruits, and oranges, just to name a few.

Studies have shown that watermelon can lower blood pressure and improve arterial compliance. Watermelons seem to work like an anti-aging remedy on arteries. But how does watermelon reduce blood pressure and make arteries “younger”?

Watermelon contains three functional important bioactive components: lycopene, arginine and citrulline. These are potent antioxidants and converted into nitric oxide, the principal vasodilatory molecule produced by endothelial cells, the inner layer of your arteries. For decades, doctors have prescribed nitroglycerin which gets converted to nitric oxide in patients with chronic angina to dilate heart arteries and relieve chest pain.  

A variety of factors can reduce the production of nitric oxide and ultimately lead to increased arterial stiffness and higher blood pressure levels such as aging, unhealthy diets, and poor exercise habits. Many people reach for arginine supplements, but the body does not absorb it well. Citrulline on the other hand is easy absorbed and converted into arginine and ultimately nitric oxide.

Watermelon provides these artery-bioactive compounds and studies indicate beneficial influence on cardiovascular health. For example, one study showed that higher lycopene levels improve arterial compliance. Watermelon bioactive compounds also seem to be anti-inflammatory and to positively impact cholesterol levels including lowering of the so-called “bad” LDL cholesterol without impacting the “good” HDL cholesterol.

In addition, watermelon is also a good food source of glutamine and Vitamin C, both of which display antioxidant properties and have been shown to enhance arterial dilation. Studies that have examined the effects of watermelon on vascular function support the notion that this functional food may improve blood pressure and arterial stiffness. 

As recommended by the American Heart Association guidelines for the detection, prevention, management and treatment of high blood pressure, a healthy lifestyle is an integral part of health maintenance and high blood pressure should be treated with lifestyle changes and in some patients with medication.

So, as long as the watermelon season lasts, let’s be health smart and add it to our diet: fresh in slices, diced in fruit salads, or as juice and take advantage of this natural remedy.


  1. Vlachopoulos C, Xaplanteris P, Aboyans V, Brodmann M, Cífková R, Cosentino F, et al. The role of vascular biomarkers for primary and secondary prevention. A position paper from the European Society of Cardiology Working Group on peripheral circulation: Endorsed by the Association for Research into Arterial Structure and Physiology (ARTERY) Society. Atherosclerosis. 2015; 241(2): 507–532.
  2. Seals DR, Kaplon RE, Gioscia-Ryan RA, LaRocca TJ. You’re only as old as your arteries: translational strategies for preserving vascular endothelial function with aging. Physiology (Bethesda). 2014; 29(4):250–264.
  3. Ellis AC, Dudenbostel T, Locher JL, Crowe-White K. Modulating Oxidative Stress and Inflammation in Elders: The MOXIE Study. J Nutr Gerontol Geriatr. 2016 Oct-Dec;35(4):219-242.
  4. Figueroa A, Sanchez-Gonzalez MA, Perkins-Veazie PM, Arjmandi BH. Effects of watermelon supplementation on aortic blood pressure and wave reflection in individuals with prehypertension: a pilot study. Am J Hypertens. 2011; 24(1):40–44.
  5. Figueroa A, Sanchez-Gonzalez M, Wong A, Arjmandi B. Arterial stiffness and blood pressure are reduced after watermelon supplementation in obese with prehypertension and hypertension. The FASEB Journal. 2012; 26:385.
  6. Figueroa A, Wong A, Hooshmand S, Sanchez-Gonzalez MA. Effects of watermelon supplementation on arterial stiffness and wave reflection amplitude in postmenopausal women. Menopause. 2013; 20(5):573–577.

Tanja Dudenbostel Headshot

Tanja Dudenbostel is an Internist, Hypertension Specialist within Cardiology at the University of Alabama at Birmingham where I divide my time as an Assistant Professor between clinical research and seeing patients in cardiology.


Un-complementing The Immune System Improves Hypertension

Even though I have been studying immunology for 15 years, I am constantly fascinated by how elaborately involved the immune system is in different diseases and conditions. I have written previously about the intricate relationship between the immune system and heart disease. In this blog, I will be highlighting the role of the immune system in hypertension, focusing on a new study that examined the role of complements and regulatory T cells in hypertension.

According to the CDC, there are 75 million people – a third of the population – in the USA with hypertension. Another third of the population is at risk, being at a pre-hypertensive state. With the change in blood pressure guidelines that was announced at the end of 2017, it is expected that the number of people affected with hypertension will increase substantially. While half of the patients with hypertension have their high blood pressure under control, hypertension still contributes to more than 1,000 deaths per day in the US.

It is evident that the immune system is involved during hypertension. Activated immune cells can infiltrate target organs such as the perivascular tissue and the kidneys. Macrophages, an innate immune and phagocytic cell, contribute to hypertension by increasing inflammation and oxidative burst. T cells, a key adaptive immune cell, can also be found infiltrating aortas, perivascular tissue, vascular vessels as well as the kidneys, where they can produce inflammatory mediators. The lack of the above two cell types has been shown to reduce blood pressure in angiotensin II infusion mouse models.

A recent study in Circulation Research examined how the complement system affected regulatory T cells during hypertension. The authors show that two complement receptors, C3aR and C5aR, are increased on regulatory T cells, an anti-inflammatory T cells that protects against heart disease. The increase in complement receptors led to a reduction of the protective regulatory T cells in hypertensive mice. By deleting the two complement receptors, the authors show that there is a decrease in systolic and diastolic blood pressure and regulatory T cells were preserved in the angiotensin II treated mice. The authors also show that similar increase in C5aR is found in patients with hypertension.

Complements are a part of the immune system that enhances the ability of antibodies and phagocytic cells to clear microbes and damaged cells, having beneficial effects in immune defense. It is already known that ischemia is a potent activator of the complement system and the activated complement system play a role in tissue damage during myocardial infarction and contribute to atherosclerosis progression. There are studies to show that inhibition of the complement system can reduce myocardial infarction. Can the inhibition of the complement system assist in hypertension reduction in patients? Would scientists be able to design therapies that limit the activation of the complement system to benefit hypertensive patients without complete abrogation of the complements anti-microbial properties? There are still many uncertainties about how the scientific community can manipulate the complement system to benefit patients with hypertension, but I think the more advances we make in understanding how the different players in the immune system affect hypertension and other heart related conditions, the better we fair in getting closer to new therapies against heart disease.

Dalia Gaddis Headshot

Dalia Gaddis is a postdoctoral fellow at the La Jolla Institute for Allergy and Immunology. She has a Ph.D. in microbiology and immunology. She is currently working on understanding the interactions between the immune system and atherosclerosis development. 


Hypertension In 2017— Individual VS Public Health Goals

Hypertension has obviously been one of the main stays of cardiovascular (CV) medicine for a long time and it is the single most modifiable CV risk factor in the world today. Hypertension had a great deal of evolution since publication of the landmark 1977 Joint National Committee report there has been progressive improvement in awareness, treatment, and control of high blood pressure (BP). Although several BP guidelines have been published since 2003, the 2017 guideline is the most comprehensive that has a new classification, definition and different goals for BP reductions.

The new guideline defines normal BP as below 120/80 mmHg and elevated blood pressure as 120 to 129 mm Hg systolic with a diastolic pressure below 80 mm Hg. Stage 1 hypertension is defined as 130 to 139 mmHg systolic or 80 to 89 mmHg diastolic, and stage 2 hypertension as 140/90 mm Hg or higher (the old definition of hypertension). What is now called stage 1 hypertension was previously labeled “prehypertension” a term meant to alert patients and to prompt physicians to provide lifestyle education to help delay development of hypertension.

Adults with an average systolic BP of 130 to 139mmHg or diastolic BP of 80 to 89mmHg have about a 2-fold increase in CV disease risk compared with a normal BP (SBP < 120 mmHg and DBP < 80 mmHg). Unlike previous guidelines, the 2017 guideline emphasizes individualized CV risk assessment and aggressive management of BP at levels of 140/90 mm Hg or higher in patients with a 10-year risk of CV events of more than 10%. Although the 10% 10-year-risk designation is not based on randomized, controlled trials, patients with BP of 130 to 139/80 to 89 mmHg would still receive non-pharmacologic treatment, unless they had a 10-year risk above 10%; in that case, a single antihypertensive agent is recommended, in concert with lifestyle changes.

Accurate and proper measurement of BP is the first most important and critical step to the diagnosis hypertension. In addition to careful BP measurement, the new guideline highlights the increasingly important role of out-of-office BP readings for confirming hypertension and recognizing white-coat and masked hypertension. It also emphasizes contemporary strategies to improve BP control, including ways to successfully implement and sustain non-pharmacological interventions, improve medication adherence, use a structured team-based approach to care, and take advantage of health information technology.

According to the new BP definitions, prevalence of hypertension increased and there is concern that a new disease designation can become a mandate for pharmacologic treatment without consideration of the patient’s risk level. However, this was an area of discussion and was explained very well in this version of guidelines. Although there are positive aspects of targeting higher-risk people with lower blood pressure for risk-factor modification, an individualized approach to hypertension can help determine the best choice for first-line therapy.

In the public health level there is a morbidity and mortality benefit, but in the individual patient level this may be hard to achieve specifically in asymptomatic patients. We are still not doing well in lowering BP and almost half of the patients are not achieving the individualized goals. However, this is the biggest place where we can have an effect and obviously why there is a national concern! It’s reasonable to consider more aggressive treatment goals in the highest-risk patients, but understanding the guideline and considering each patient according to their risk factors and complex medicine problems become more critical.

Fawaz Alenezi Headshot
Dr. Fawaz Abdulaziz M Alenezi is a Clinical Imaging Fellow at the Duke University Health Systems. He conducts medical research on the derivation and validation of novel echocardiographic approaches to myocardial deformation and a new echocardiographic technique which assists patients with heart ventricular function.


Manual Versus Automated Office Blood Pressure Measurements

Although the awareness and treatment of hypertension has increased steadily over the past decade, it is estimated that approximately 50% of patients are still not adequately controlled. However, blood pressure measurement techniques vary widely and results from studies are difficult to compare. Further, office BP measurements depend on time, resources, and equipment.

In our referral Cardiology-Hypertension Clinic blood pressure is measured in different ways by different providers:BP measurement tools

  1. Manual
  2. attended automated office BP (AOBP) with 3 consecutive readings (Omron) or
  3. unattended attended automated office BP (AOBP) with 3 consecutive readings (Omron) or 6 consecutive readings (BPTrue).

“Attended” means that trained personnel stays in the room, while in unattended measurements trained personnel leaves the room and monitors are either programmed to take 3 or 6 consecutive readings.

These different approaches make it difficult to compare BP levels and to adjust medication to achieve target BP.

So what is the best way to measure blood pressure and which is the one we should stick to?

It is known that BPs taken manually can differ from those taken using an automated device in the clinic or office. Several studies have shown that manually taken BPs can be higher than AOBP.  Further, many clinicians prefer AOBP over manual BPs since it is an easy way to check BP several times.

With advances in technology, unattended AOPB measurements are possible. Research suggests that unattended blood pressure measurements are significantly lower than attended blood pressure measurements.

Clinical trials using AOBP usually pre-specify how to measure BP i.e. either attended while trained personnel stays in the room or unattended i.e. medical staff comes back after a few minutes and retrieves BP readings.

The importance of a consistent way to measure BP has come under scrutiny in the SPRINT study.

Although blood pressure measurements in this study were obtained using an automated measurement device, there were substantial differences in the methods used by the different SPRINT centers. In particular, medical staff were inconsistently present or absent when blood pressure readings were taken, between centers and perhaps within centers.

Blood pressure in SPRINT was defined as the average of three measurements taken with an automated measurement device. But until now it has not been entirely clear whether these measurements were obtained in the presence or absence of medical staff.

Results of a survey for the SPRINT trial showed that patients were completely alone during the measurement period at 43% of the sites and were alone (unattended) for part of the time at 29% of the sites. However, within sites significant internal variation in their BP measurement techniques (unattended and attended AOBP) may have occurred.
What is clear is that there are a variety of methods currently employed to measure BP in clinical trials and in the office, and that technique, environment, and equipment can influence BP levels obtained.

To put that in perspective for clinical practice we should take this into consideration and report how BP was measured when we communicate with our patients or colleagues.

Bp levels

Tanja Dudenbostel Headshot

Tanja Dudenbostel is an Internist, Hypertension Specialist within Cardiology at the University of Alabama at Birmingham where I divide my time as an Assistant Professor between clinical research and seeing patients in cardiology.



Tardiness Of Science Leads To Public Skepticism

Man with heart surgery scar

AHA17 introduced the new and controversial blood pressure measurement guidelines during its annual conference in Anaheim, CA, raising skepticism among the masses. However, before I get into what the new recommendations are, let’s review how blood pressure measurements were initially established. Historically, over the last century blood pressure was unstudied by the scientific and clinical communities. The realization of the importance of blood pressure to health was first observed over 4,000 years ago by Huang-Ti, the yellow Emperor of China, with the discovery that people who ate too much salt had “harder” pulses and subsequently suffered from more strokes. Precise blood pressure measurements did not come about until Samuel Siegfried Ritter von Basch developed the sphygmomanometer for clinical use in 1880. The concept of hypertension, previously termed hyperpiesia, did not make an appearance until 1896 with the introduction of auscultating Korotkoff sounds (the sounds heard through the stethoscope when the artery is occluded by the sphygmomanometer and pressure released slowly). Having this new technology revolutionized the means of measuring blood pressure.

As the technique for blood pressure measurement developed over the years, so did the basis for the clinical diagnosis of hypertension. However, there was still debate as to how to treat it. In 1949, Charles Friedberg suggested in the textbook “Diseases of the Heart” that mild ‘benign’ hypertension (210/100 mmHg) should not be treated. During this era, blood pressure treatment was so controversial that the common thought was, ‘the greatest danger to a person with high blood pressure was knowing, because some fool will try to reduce it’. To put that statement into perspective, this was still a time when people were bled by leeches to reduce blood pressure leading to increased incidences of death due to the treatment regimen. The next era of treatment was to do nothing. Researchers started to explore the idea that high blood pressure was a compensatory mechanism, which should not be tampered even if clinicians were certain it could be controlled. This line of thinking lead to a significant increase in morbidity and mortality due to the prevalence of cardiovascular disease caused in part by the untreated blood pressure. With this revelation, high blood pressure treatment and diagnosis was forever changed, starting with the level that is considered to be high (140/80 mmHg).

The first clinical breakthrough in hypertension treatment was the discovery of diuretics. The addition of this drug class reduced strokes and ischemic heart disease by ~50% between 1972 and 1994. Once beta blockers came on the scene for the use of angina, researchers found, by accident none the less, that they additionally lowered blood pressure. How about that?! With research advancing in the area of hypertension, there have been several drugs to come on the market to lower blood pressure including calcium channel blockers and sartan drugs. These medications have had enormous benefit in reducing cardiovascular disease.

This leads us to the new classifications of normal and high blood pressure. At AHA17, the new range for defining systolic/diastolic blood pressure in patients is as follows: normal (90-119 mmHg/60-79 mmHg), prehypertension stages I (120-139 mmHg /81-89 mmHg), and stage II (≥160 mmHg/ ≥100 mmHg), as well as isolated systolic hypertension (≥140 mmHg /<90 mmHg). These measurements are based on the average seated, relaxed blood pressure reading obtained over two or more office visits. Although these are the new recommendations, these numbers are interpreted in conjunction with the clinician’s understanding of the patient’s history. For example, if a patient has a blood pressure of 130/80 mmHg coupled with other chronic diseases, such as diabetes mellitus type 1 or 2 or kidney disease, then this might require more aggressive treatment than a patient with no underlying disease. Physicians will furthermore take into account a patient’s age and overall health when making the decision of how or when to medicate. For example, a patient with resistant hypertension (blood pressure that fails to be reduced with appropriate antihypertensive medicine) may require additional drugs. Because we know that hypertension can be a consequence of both environmental and behavioral factors, AHA still suggests that we adopt a healthy lifestyle that includes a diet focused on heart health, as well as incorporating exercise into our activities of daily living.

There has been some controversy in the news and on social media about these changes. Whether these changes are in the best interest of the general population or in the interest of those who stand to gain from more people having hypertension. This could indeed lead to more patients taking medicine, and consequently more people having higher insurance premiums. It could also lead to more income for primary physicians and pharmaceutical companies. With these things being considered, none of them are more important than one’s health! There are things that cannot be controlled, such as age, sex and genetics, but that does not change the fact that it is the individual’s responsibility to live a healthy lifestyle and take control of their health care. This starts by knowing your risk, eating healthy, and regular exercise.

I know this is a lot of information to take in, but the real message here is: (1) do not allow social media to dictate your health. There are going to be a lot of things said by all types of people, but the best resource is your clinical staff. (2) Yes, regular medical appointments are still necessary to determine whether blood pressure should be treated or how it should be treated. (3) Although the blood pressure scale has changed slightly to incorporate more hypertensive stages, the definition of a healthy blood pressure has not really been modified. Experts (clinicians and scientist) are at odds as to whether patients over 70 years of age should be treated with additional medicines in order to reduce blood pressure. To add more antihypertensive drugs to a patient in such a vulnerable age group could lead to increased side effects such as hypotension, dizziness, increased prevalence of renal failure, enhanced fall risk, and alterations to activities of daily living. There are guidelines published in the JAMA for more information on the recommendations for the geriatric population. Science takes time. It takes a lot of studying to get the results that change the way experts view our clinical practice. It may seem to the general public that these data are tardy, but they are, in my opinion, timely.

I am interested in knowing more about the benefits of the new blood pressure scale and how this will tangibly change the occurrence of cardiovascular disease, cardiorenal disease, and chronic renal disease. I also wonder what questions will now arise in the general population regarding these new developments.

Anberitha Matthews, PhD is a Postdoctoral Fellow at the University of Tennessee Health Science Center in Memphis TN. She is living a dream by researching vascular injury as it pertains to oxidative stress, volunteers with the Mississippi State University Alumni Association, serves as Chapter President and does consulting work with regard to scientific editing.


Back To Reality: Incorporating Scientific Sessions Into Everyday Life

Nearly 2 weeks after AHA Scientific Sessions 2017, I’m back at home, sipping coffee on a chilly Sunday morning and thinking about Anaheim. The larger-than-life convention center, the numerous and packed sessions, and the built-in-a-day pharma fueled exhibit halls.

Working backwards, I remember fitting in a lunch sponsored by Amgen, given by Dr. Alan Brown, Director of Cardiology at Advocate Lutheran General Hospital. It boasted boxed lunches but lacked elbow room, but by the end of the hour, I was impressed.

As a trained dietitian, I’m aware of at least some of the challenges in providing patient care. With new lipid guidelines, new blood pressure guidelines, new everything guidelines, up until now, the ease of popping a pill has seemed to rise above the effectiveness of lifestyle changes.

For the first time, I heard physicians calling on one another to sit face-to-face and eye-to-eye with their patients, and ask them about their physical activity. And their eating habits. In Dr. Brown’s words, by asking about these topics, you communicate to your patients that they are important.

Vegetables on the kitchen counter

(The DASH Diet stands for Dietary Approaches to Stop Hypertension and is rich in fruit, vegetables, low-fat dairy while reduced in saturated fat and cholesterol. Content Provider: CDC/Amanda Mills. 2011)

At this same conference, Dr. Stephen Juraschek presented his results using the DASH diet – “The Effects of Sodium Reduction and the DASH Diet in Relation to Baseline Blood Pressure,” published just a few weeks ago. The investigators randomized adults with pre- or stage 1 hypertension (and not using blood pressure lowering medications) to DASH diet or control diet. Then in random order, over 4 weeks with 5-day breaks, participants were fed at 3 sodium levels: 50, 100, 150 mmol/day at 2,100 kcal. And what did they find? Adopting the DASH diet in combination with reduced sodium intake achieved “progressively greater reductions at higher levels of baseline SBP [≥150 mmHg]”.

So why am I talking about lifestyle modifications in a post about incorporating conference learnings back into your everyday reality at work? Well, a big announcement that came out of AHA17 was the new hypertension guidelines. I noticed recurrent statements and questions about these guidelines, in presentations, on social media, and from my peers when I returned home. 

At our first peer led research meeting back from AHA17, I printed off a few copies of the Top Ten Things To Know (PDF) about the 2017 hypertension guidelines. We touched on the implications of new classification categories – more treatment, higher prevalence, changes in comparisons over time in our epidemiologic studies. 

Connie Alfred (left), of the National Center for Infectious Diseases (NCID), was shown having her blood pressure taken by Robyn Morgan, of the National Center for Chronic Disease Prevention and Health Promotion

(Connie Alfred (left), of the National Center for Infectious Diseases (NCID), was shown having her blood pressure taken by Robyn Morgan, of the National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP), during a free blood pressure screening event that was held on all CDC campuses in 2005. Content Provider: CDC/CDC Connects. 2005.)

We were happy to see the focus on accurate measurement of BP, ensuring adequate rest time and taking averages of measurements, a technique we use in epidemiologic studies to minimize measurement error. Those of us particularly interested in physical activity and nutrition epidemiology rejoiced at the lifestyle modification efforts. We closed the discussion with an acknowledgement of conflicting and numerous other guidelines, the reality of putting them into practice – from primary care to cardiology clinics – as well as misinformation in the media coverage of the guidelines, such as misquoting the relaxed recommendations for older adults. 

With so much to chew on, I closed the discussion encouraging everyone around the table to think more on the implications of new guidelines, and our role in developing them, implementing them, and evaluating them.

Bailey DeBarmore Headshot

Bailey DeBarmore is a cardiovascular epidemiology PhD student at the University of North Carolina at Chapel Hill. Her research focuses on diabetes, stroke, and heart failure. She tweets @BaileyDeBarmore and blogs at baileydebarmore.com. Find her on LinkedIn and Facebook.