Prognostic Value of Ambulatory Blood Pressure Monitoring in Obese Patients

Abstract

In this issue of the Journal, Palatini and his colleagues 1 ask and answer an important question. The question is simply this: because blood pressure (BP) measurement is prone to error in patients with obese arms, is ambulatory BP monitoring (ABPM) as accurate in obese patients as in the nonobese? Or, put another way, if ABPM is shown to be inaccurate in obese patients, other methods of measurement will have to be devised for this population of patients who constitute as many as 30% of individuals with hypertension. Palatini's group approaches the problem in a unique manner. Rather than simply comparing ABPM measurements in obese patients (with a large arm circumference) with nonobese patients (with normal arm circumference), they chose to examine cardiovascular outcome in obese and nonobese patients who had both office BP and ABPM performed, the premise being that if predictive values for cardiovascular events (CVEs) with ABPM are similar in both groups, the technique can be recommended for obese as well as nonobese patients. There are many reasons as to why ABPM might be inaccurate in obese individuals. These include technical problems related to arm size and adiposity that might lead to failed readings, negating the benefit of recording BP in ambulatory conditions; the use of monitors provided with undersized cuffs leading to overestimation of ABPM in obese arms; the discomfort caused by repeated long inflations of a large cuff causing disruption of nighttime sleep with falsely elevated BP readings; inappropriateness of cuff shape as cylindrical cuffs do not always wrap snugly around conically shaped upper arms in obese patients; and oscillometric measurements can be influenced by the stiffer arteries often present in obese patients. Furthermore, it is possible that current measurement ABPM algorithms are not adjusted for obese arms because validation protocols do not consider arm circumference as a selection criterion for testing monitor performance and usually only a few obese patients are recruited in validation studies. For these reasons, the reliability of ABPM in obese patients is often questioned. The recent European Society of Hypertension guidelines recommend, therefore, separate validation of ABPM devices in obese people.3 However, the practical difficulty (and cost) of such studies means that, in effect, specific validation studies have not been performed in the obese population.The Ambulatory Blood Pressure-International Study is an international registry established to promote the investigation of the relationship of noninvasive 24-hour ABPM with morbidity and mortality in a large patient population recruited in different countries. 4 The database was constructed by data from three European, three Japanese, one North American, and one Australian center, in which there were 10,817 individuals (5136 women and 5681 men, 9408 nonobese and 1409 obese) aged older than 60 years who had casual BP measurements and 24-hour ABPM performed under standardized conditions. Average 24-hour BP was superior to off...

Chest Wearable Apparatus for Cuffless Continuous Blood Pressure Measurements Based on PPG and PCG Signals

“…Cardiovascular diseases and the related hypertension condition are a worldwide health issue for patients, so that continuous and reliable BP monitoring is crucial for longterm diagnostic purposes [8]. From a clinical point of view, the pressure holter setup using a cuff, which consists of the automated measurement of BP every 15 to 30 minutes along a period of 24h, represents the standard (non-invasive and cost-effective) methodology in hypertension assessment and cardiovascular risk evaluation [37], [38]. However, conventional BP holter equipment, using either auscultatory or oscillometric techniques, provides BP readings at discrete time intervals and cannot support continuous measurements during daily activities.…”