Ambulatory Blood Pressure Checkups versus Clinic Blood Pressures

General internists and family practitioners have very little equipment to use in diagnosing our patients other than a light, a reflex hammer, a stethoscope, an EKG machine, a spirometer (to test breathing) and a pulse oximeter. Some offices still have an x- ray suite today but that is less common in small independent practices.

The ambulatory blood pressure cuff is a device introduced as a way to test whether patients with office-based hypertension had an isolated anxiety elevation of their blood pressure because of the physician’s “white coat” or an ongoing problem that needed to be addressed. The monitor itself is a routine blood pressure cuff with a computer device and timed inflation and deflation mechanism. It was designed to take six blood pressure readings per hour while you were awake and four readings per hour during the night.

Patients are asked to bathe and groom themselves prior to arriving for an appointment and we then placed the cuff on their arm and activated the device. They returned it the next morning and we connected the recording chip to our computer. We received multiple readings per hour and the machine calculated average blood pressure readings, made graphs and answered the question of what type of blood pressure elevation we had seen in our office.

We have performed hundreds of these procedures on patients and it is extremely rare to see a report of a sustained or average elevation of the systolic or diastolic blood pressure in a range that requires the use of medication. We only use the ambulatory monitor on patients who took their blood pressures at home and said it was normal but always had a dramatic elevation while in the doctor’s office.

I was entirely surprised to read the article in Circulation which looked at employees of the State University of New York at Stony Brook and Columbia who had ambulatory blood pressures compared with “clinic” blood pressures. 893 individuals wore the ambulatory monitor and were compared to 942 who had clinic blood pressures taken. These were all young healthy individuals with none taking blood pressure treatments.

They found that the ambulatory monitor readings were higher (average 123/77) compared to clinic readings which averaged 116/ 75. The average BP was 10 mm higher in young healthy adults with a normal body mass index. This elevated ambulatory blood pressure was found to be most pronounced in young healthy individuals with the difference being less apparent with increasing age.

While the result was surprising it still supports the use of the machine in our older population of individuals who come in with a story of elevated blood pressures in the doctor’s office but normal blood pressures at home. We will continue to use the machine for just that purpose.

International Panel Questions the Wisdom of Strict Sodium Guidelines

A technical paper published in the online version of the European Heart Journal suggested that individuals should strive to keep their sodium intake to less than 5 grams per day. This is in marked contrast to the recommendations of the American Heart Association of 1.5 grams per day and American College of Cardiology recommendations of 2.3 grams per day. The authors of the papers included some of the world’s experts on the topic of hypertension including Giuseppe Mancia, MD, Suzanne Oparil, MD and Paul Whelton, MD.  They agreed that consuming more than five grams per day was associated with an increased cardiovascular risk. They believe there is no firm evidence that lowering the sodium intake to below 2.3 or 1.5 grams per day reduces cardiovascular disease without putting you at risk of developing other health issues from having too little sodium.

The report triggered a firestorm of controversy in the hypertension and cardiovascular field with proponents on each side of the issue. Both sides agreed that we need more meticulous research to determine the best lower end of daily sodium intake because current information makes recommending one level or another a guess at best with little data to back you up. That leaves clinicians and patients scrambling for clarity and the media reporting this paper in a manner threatening to further erode the public’s confidence in the scientific method and physicians in general.

As a practicing physician I will continue to recommend a common sense approach to salt intake. Those patients who have a history of congestive heart failure or hypertension which is volume related will still be encouraged to read the sodium content of the foods they are purchasing and try to avoid cooking with or adding sodium chloride to their food at the table. This will be especially important for patients with cardiomyopathies and kidney disease who are following their daily weights closely. For the rest of my patient population I will ask them to use salt judiciously and in moderation only. I will suggest not adding salt at the table and if they do to please add it in moderation. I will allow more salt intake in those patients who work outside all day and are exposed to our high temperatures and humidity.

Like everyone else, I will wait for the meticulous research studies to be performed over time to determine how low and high our sodium chloride consumption should be without hurting ourselves.