Mobile Monitoring of Blood Pressure

Hypertension or High Blood Pressure, it has been called a “Silent Killer”. Not because it quietly stalks its prey, ready to pounce, but because many of its victims are not even aware of the problem, until it’s too late. Dr. Thomas Pickering of Columbia Presbyterian Medical Ctr. explains. It is correct to refer to Hypertension as a “silent killer” because most people do not have any specific symptoms as a result of having high blood pressure unless it is extremely high, which is relatively rare. Traditionally high blood pressure is defined as a blood pressure greater then 140 over 90, and the reason why elevated blood pressure is of such concern is because it leads to stroke, heart attack, blood vessel disease, and kidney failure. When we measure blood pressure, we measure the force that the blood exerts against the vessel wall. And we measure it in 2 phases of the pumping action of the heart. So typically as you know you get two readings from your physician, the upper number the systolic blood pressure lets say 140, and the lower pressure the diastolic blood pressure let’s say 90.”

And while we are all familiar with the Blood Pressure cuff and various other electronic devices used to measure blood pressure, diagnosing true hypertension is not as easy as it may seem. In fact, for some the very act of having blood pressure taken, can often give a false reading. This is a phenomenon known as White Coat Hypertension. White Coat high blood pressure is when a patient has an elevated blood pressure in the office, but a normal blood pressure outside of the office. And doctors know from studies that have been done over the past twenty-five years that about 25% of patients experience this phenomenon. Typically the way a doctor would diagnosis “white coat” is to ask the patient to take their blood pressure at home, or at their office with a home BP monitor device that they can purchase. However the accuracy of such home devices can sometimes be questionable, and changes in daily activities can also cause readings to fluctuate. Physicians agree the best way to get a truly accurate evaluation of a patients risk, would be to monitor their blood pressure continuously. By wearing a device known as an ABPM, or Ambulatory Blood Pressure Monitor. With an ABPM, measurements are taken around the clock, giving clinicians all the information needed to make an accurate diagnosis of hypertension. William Neiger, with Spacelabs one of the manufactures of such a device describes the concept. “The ambulatory aspect of our blood pressure monitoring device enables the patient to wear the monitor throughout their normal daily activities so that they are not limited to just measurements in the physicians office they can get them at home, at work, even while they are sleeping. The ambulatory monitoring has several advantages. First of all in the patient that you are not sure if they have high blood pressure or not, it gives you the most accurate diagnosis.” Dr. Pickering adds, “âÂ?¦another way that we use ambulatory blood pressure monitoring is that many times patients come in to the office on several different medications, they’ve been treated by another physician, or we’ve been doing it ourselves and we can’t get their blood pressure down and then we do the 24 hour monitor and we see is it true that the blood pressure’s really elevated, or in fact is it actually normal. And more often then not the blood pressure’s much better controlled outside the office then what we see inside the office.”

Ambulatory Blood Pressure Monitoring is proving to be valuable diagnostic tool not only in the practice of medicine but, in clinical trials and studies that are trying to determine the effect hypertension has on disease states. “Another way that we use ambulatory blood pressure monitoring in clinical trials is to try to determine if the patterns of blood pressure that we can determine using this technique are related to stroke, heart attack or kidney disease.” Says Dr. Robert Phillips, with the Lennox Hill Heart & Vascular Institute. “One of the major trials that we’re doing this in is the African American Study of Kidney Disease and Hypertension, the ASKH Trial which is sponsored by The National Institute of Diabetes, Digestive and Kidney Diseases. And in this study our hypothesis is that one of the reasons that African Americans have such a high incidence of kidney disease associated with hypertension, which in fact is four fold greater then in the Caucasian population, is because their blood pressure does not drop at night, and in fact our preliminary data suggests that this is the case. That African Americans don’t drop their blood pressure at night and in fact their blood pressure may rise during sleep. Now we never would have been able to find this out from just using casual office blood pressure readings.”

The results of these and other studies have shown that there is a lot of evidence now of the predictive value of ABPM’s Doctors are comfortable in stating that if there is a discrepancy between the blood pressure recorded by the doctor and by one of these automatic monitors, it is the blood pressure recorded by the monitor that gives the best prediction of whether or not that particular patient is at risk of having a stroke or heart attack down the line.

High Blood Pressure and Heart Disease claim the lives of thousands of victims annually. While research into effective treatments continues, medical experts agree prevention and early diagnosis are the keys to reducing those figures. Eating right, exercise, and a little help from technology may keep us one step ahead of these killers.