Not long ago, we published an article in the Herald Journal discussing the new hypertension guidelines made public last year. Articles continue to appear in the medical literature documenting the importance of maintaining healthy blood pressures. So, the question arises, what are the best ways to determine if a person’s BP is optimally controlled? Typically, this has been done by periodic BP measurements in physicians ‘offices or at home monitoring by patients. Available for a number of years, but used infrequently, is testing known as Ambulatory Blood Pressure Monitoring (ABPM).
Most of you are aware that hypertension (HTN) is a medical diagnosis made when a person has repeated or persistent elevations in their BP. The term hypertension is derived from ‘hyper’, meaning excessive, and tension, meaning ‘force’. This ‘excessive force’ is in the arteries of the body and people with untreated or poorly controlled HTN, over a period of time, are at high risk for heart attack, stroke, kidney failure, and congestive heart failure.
HTN is a very common condition and has frequently been referred to as “the silent killer’ because it typically does not cause symptoms that would alert someone to its presence.
As a review from the last article, it has been known for decades that maintaining a “normal” blood pressure is critical for health maintenance. The current threshold BP for diagnosing HTN is persistent BP’s greater than 130/80. As related in the previous article, a meta-analysis of the hundreds of clinical investigations performed over many years, quantitated the risk of developing the complications mentioned above as follows: beginning with a systolic (top number) BP of 115 mmHg, for every 20 mmHg increase in this pressure, the risk of complications doubles. In other words, if a population of people with an average systolic BP of 115 mmHg is compared to a group with an average of 135 mmHg, the risk of complications doubles in the latter group. Furthermore, if people with an average of 155 mmHg (135 + 20) are compared to the 115-mmHg group, the risk is four times greater.
The good news is that if HTN is detected and treated, particularly early in its onset, with lifestyle changes and/or medications, the risk incidence is reduced to that of the general population who do not have HTN.
An individual’s BP can be very labile and vary in seconds to minutes due to many factors. Two important factors to consider in diagnosing HTN and determining adequate control in patients being treated, is the method used to measure the BP and the nature of the environment at the time of the measurement. Most diagnosis of HTN are based on BP’s obtained in physician’s offices, or other healthcare facilities. Occasionally, BP elevations are uncovered by individuals obtaining measurements at home or in pharmacies.
Many people are tense and anxious when getting a BP check, particularly in a physician’s office, and this can lead to the finding of significantly higher BP’s then when measurements are taken in other environments. This is known as White Coat Hypertension (WCH). One method of excluding this diagnosis is to have the patient measure BP’s at home and submit a diary of the results. The issues with this approach are questions concerning the accuracy of the home equipment, the technique used, and the influence on the BP of a person’s subconscious concern about the results of the measurement.
As mentioned earlier in this article, technology is available to neutralize the influence of these factors and is known as Ambulatory Blood Pressure Monitoring (ABPM). An ABPM determines BP’s using a device that is worn by the patient that automatically takes BP measurements every 15-30 minutes over a 24-48 hr. period, including checks during sleep. These measurements are made while a person is involved in their usual daily activities and in a typical environment. The patient is not thinking about the BP results during the measurements. After the data is obtained, it is analyzed by computer software.
There are other benefits, other than an evaluation for WCH. The same device and process can be used to determine if a patient being treated for HTN is well controlled for an entire 24 hr. period. Many antihypertensive meds claim 24 hr. efficacy with once daily dosing. However, because of metabolic variability in patients, some may require split dosing to get true 24 hr. coverage.
Finally, there is a physiologically expected drop in BP during sleep known as ‘dipping’. The average BP drop during sleep is 15% lower than day-time values. Current investigations are demonstrating that ‘non-dipping’ maybe a significant risk factor for cardiovascular disease and could help explain the high incidence of heart attacks and strokes in the morning hours. This condition is uncovered by the use of ABPM.
Recent clinical studies have demonstrated that ABPM’s are more predictive of CV events and progression of renal disease than in-office or at-home BP checks.
ABPM is a valuable clinical tool in preventive healthcare. Unfortunately, ABPM’s are rarely utilized in physician’s practices due to the high initial equipment investment expense and the poor reimbursement from private and government third party payers. It must be said that this is just one example of many of how third- party payers inappropriately influence the delivery of quality healthcare.
Dr. Tippett is the founder of CQHP, a concierge internal medicine practice located at 1210 Commerce Dr. Suite 106, Greensboro, Ga 30642. He can be reached at 706-510-3659. Visit his webpage at www.drtippett.com