Measuring blood pressure accurately.

Introduction For practical reasons, blood pressure values measured by physicians or nurses in a medical environment remain the clinical basis of the diagnosis and management of arterial hypertension around the world as recommended by all guidelines [1–4]. Nevertheless, measurements of blood pressure outside the office have gained an increasing popularity over the last decades not only to ascertain the diagnosis of hypertension but also to follow the impact of therapeutic interventions. Out-of-office blood pressure measurements can be obtained either by 24-h ambulatory blood pressure monitoring or by home blood pressure monitoring. As reviewed recently [5], both sets of out-of-office blood pressure offer undeniable advantages when compared to office blood pressure. First, both ambulatory blood pressure and home blood pressure monitoring provide more reliable and reproducible information on blood pressure. Second, blood pressure values obtained by ambulatory blood pressure and home blood pressure monitoring appear to be more closely related to target organ damage than office blood pressure and hence have a greater prognostic relevance than office blood pressure. Third, certain diagnosis such as white coat hypertension and masked hypertension can only be diagnosed using out-of-office blood pressure measurements. Fourth, when used in the clinical follow-up of treated hypertensive patients to evaluate the impact of drug treatment, ambulatory blood pressure monitoring as well as home blood pressure monitoring has the advantage of not being affected by a placebo effect. Finally, evidence has been provided that treatment-induced reduction in 24-h blood pressure may predict better than office blood pressure the regression of end organ damage (particularly the cardiac one) induced by antihypertensive drug. Many of these information have been achieved during the past two decades by a number of studies carried out in different populations around the world, including the Pressioni Arteriose Monitorate E Loro Associazioni (PAMELA) study [6–10]. When should out-office blood pressure be measured? Despite their advantages, ambulatory blood pressure monitoring as well as home blood pressure monitoring is not regarded as a routine procedure that should be applied to all hypertensive patients essentially for economical reasons. However, this issue is debated because the clinical information gathered with these measurements may potentially result in financial savings when applied adequately. The European and American guidelines for the management of hypertension have defined some indications for the use of ambulatory blood pressure monitoring in hypertension [1,2]. These include patients with resistant hypertension, patients with a high variability of office blood pressure, low-risk patients with a high blood pressure, patients with suspected episodes of hypotension, patients with a large discrepancy between office and home blood pressures, and finally patients with special clinical conditions such as pregnancy or sleep apnea syndrome. Outside these indications, the use of ambulatory blood pressure monitoring could be discussed both in terms of feasibility and economics. Theoretically, a measurement of out-of-office blood pressure could be recommended to all new patients with as suspected hypertension to confirm the diagnosis of hypertension and to refine the patient's cardiovascular risk profile. Therefore, ambulatory blood pressure monitoring could be recommended to all high cardiovascular risk patients before starting any treatment and later under therapy to ascertain the adequacy of the control of blood pressure. Ambulatory blood pressure values in diabetic patients In this issue of the Journal of Hypertension, Leitao et al.[11] report the results of a cross-sectional study performed to estimate the daytime ambulatory blood pressure monitoring values corresponding to the target office blood pressure of 130/80 mmHg for diabetic (as defined by the American Diabetes Association) and to assess which diabetic patients may actually benefit from ambulatory blood pressure monitoring. They included 554 patients in this analysis. Regression analyses were performed to analyze the ambulatory blood pressure monitoring values corresponding to office blood pressure and receiver operating characteristics (ROC) curves were used to assess the sensitivity and specificity of office blood pressure in diagnosing daytime ambulatory blood pressure monitoring hypertension. According to their regression equations, the daytime ambulatory blood pressure monitoring corresponding to the target office blood pressure of 130/80 mmHg was 129/79 mmHg and the daytime ambulatory blood pressure monitoring value corresponding to 140/90 mmHg at the office was 134/82 mmHg. As expected, discrepancies between ambulatory blood pressure monitoring and office blood pressure were due essentially to masked hypertension (about 10% of cases) and white coat hypertension (between 19% for systolic blood pressure and 26% for diastolic blood pressure). Interestingly, when office blood pressure was lower than 120 mmHg systolic and 70 mmHg diastolic, the sensitivity to rule out hypertension using ambulatory blood pressure monitoring was 90%. Similarly, when office blood pressure was more than 145 mmHg systolic and more than 90 mmHg diastolic the sensitivity to confirm hypertension using ambulatory blood pressure monitoring was 90%. Within these two sets of limits, 38% of patients would be misclassified if only office blood pressure values would be considered for the diagnosis. Thus, using the cut-off values of less than 120/70 mmHg and more than 140/90 mmHg at the office, 56% of the population sample would need an ambulatory blood pressure monitoring to confirm the diagnosis of hypertension. According to these results, only diabetics with an office blood pressure between 120 and 140 mmHg systolic and/or a diastolic blood pressure between 70 and 90 mmHg would really benefit from an out-office assessment of blood pressure. This would limit the use of ambulatory blood pressure monitoring to only 50% of the diabetic patients. Studies implications and limitations The results of this provide interesting practical information on the use of ambulatory blood pressure monitoring in diabetic patients. However, they also have some limitations. The first one is the fact that the entire analysis is based on daytime ambulatory blood pressure only. Although the authors have measured 24-h blood pressure, they have not considered the nighttime blood pressure. This is unfortunate because there is increasing evidence that nighttime is a better predictor of cardiovascular risk than daytime blood pressure. Moreover, diabetic patients are often characterized by an absence of the physiological fall in blood pressure reflecting a nondipping pattern at night. Diabetes may even be the cause of a reverse dipping, that is an increase in blood pressure at night. Both the nondipping and the reverse dipping pattern of blood pressure have been associated with an increased risk of developing target organ damages such as left ventricular hypertrophy, microalbuminuria, renal dysfunction, and cerebral vascular lesions [5,12]. Thus, when assessing the cardiovascular risk profile linked to hypertension in diabetic patients, nighttime blood pressure should be included. Indeed, it is not uncommon in diabetes that daytime normotensive patients exhibit a nocturnal hypertension. This type of patients would be misdiagnosed using the algorithm proposed by the authors. Recently, the results of the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial have shown that in diabetic patients the reduction of cardiovascular morbidity and mortality obtained by lowering office blood pressure below 120 mmHg systolic is not greater than that seen reducing blood pressure below 130 mmHg [13]. On the contrary, a systolic blood pressure below 120 mmHg may result in an increased risk of developing cardiac complications, as suggested by the recent post hoc analysis of diabetic patients with coronary heart diseases having participated in the INternational VErapamil SR-Trandolapril (INVEST) Study [14]. If a low blood pressure increases the risk of cardiac complications in diabetics, one might have to reconsider the necessity to perform an ambulatory blood pressure monitoring in diabetic patients with a blood pressure <120/70 mmHg in contrast to the proposals of Leitao et al. Indeed, in treated diabetic patients with a low office blood pressure, ambulatory blood pressure monitoring could be of importance to diagnosis episodes of asymptomatic hypotension episodes which might increase their cardiac risk. Thus, in the analysis of daytime and nighttime blood pressure values, it would be of interest to assess whether the percentage of ambulatory blood pressure values below a certain level is indeed associated with an increased risk of some cardiovascular complications. In this respect, it is important to mention that the analysis presented by Leitao et al. does not provide any information on the presence in this particular patients population of cardiac organ damage. The study also does not provide any data such on the occurrence of cardiovascular events and deaths, as it was not a prospective cohort study. Both these two sets of information should be thus provided by future clinical trials.

Ambulatory blood pressure (ABP) monitoring is increasingly recognized as a valuable tool to refine prediction of cardiovascular risk related to blood pressure (BP).1 After the first landmark study published by Perloff and colleagues 24 years ago,2 several longitudinal event-based studies provided unequivocal evidence of an independent association between ABP and risk of cardiovascular disease. Although experimental procedures and statistical analyses varied from study to study, ABP generally improved cardiovascular risk stratification over and beyond traditional risk factors, including clinic BP.3 The Table, obtained through an electronic search of literature using the terms “ambulatory blood pressure” and “prognosis,” shows a list of longitudinal event-based studies performed by independent groups. It is worth noting that the list of available studies is longer because each group generally published other analyses of their database. Only the first-appearing or main contribution from each group has been included in the Table. View this table: Longitudinal Event-Based Studies From Independent Groups That Addressed the Prognostic Value of ABP Article p 2145 Three aspects of available investigations deserve special mention. First, the prognostic value of ABP has been examined not only in subjects with clinical diagnosis of hypertension but also in the general population and in a variety of settings, including diabetes mellitus, renal failure, and cerebrovascular disease. Second, subjects could be untreated or treated at the time of ABP monitoring. This point may raise concerns, because drug treatment could exert unpredictable effects on 24-hour ABP profile and, consequently, interpretation and applicability of results. Third, although a continuous relation emerged in most studies between ABP and cardiovascular risk, several investigators tried to define clinical categories based on arbitrary thresholds of ABP. Although such categories are potentially useful to make diagnostic and therapeutic decisions in clinical practice, their prognostic role requires confirmation from large and independent cohort …

Ambulatory blood pressure (BP) monitoring as an adjunct to casual/clinic BP measurements is currently used widely for the diagnosis and treatment of hypertension. It has been established that ambulatory BP monitoring is essential to confirm "white coat" hypertension, drug-resistant hypertension, duration of drug action, short-term BP variation, and nocturnal and on-the-job BP levels. It is estimated that approximately 10,000 ambulatory BP monitoring devices are currently used in Japan. That number would increase if 1) a standard algorithm with a theoretical basis to determine BP levels is introduced for ambulatory BP monitoring devices based on cuff-oscillometric method, 2) the reproducibility of ambulatory BP levels is confirmed, 3) reference values for evaluating ambulatory BP monitoring levels are established, and 4) the clinical significance and prognostic value of ambulatory BP monitoring is established. If such problems is settled, the use of ambulatory BP monitoring in the diagnosis and treatment of hypertension would be national health insurance and would improve the prognostic accuracy of evaluating hypertension as well as the cost-effectiveness of screening, diagnosis and treatment of hypertension.

The 2006 Canadian Hypertension Education Program recommendations for the management of hypertension: Part I – Blood pressure measurement, diagnosis and assessment of risk

: The diagnosis and management of hypertension is dependent upon accurate blood pressure (BP) measurement. Despite intense efforts over several decades by the international medical community worldwide, the use of inaccurate devices has resulted in the misdiagnosis and poor management of hypertension, which remains a largely unresolved public health problem. STRIDE BP (www.stridebp.org) is an international nonprofit organization the mission of which is to improve the accuracy of BP measurement and the diagnosis of hypertension. STRIDE BP comprises a group of 24 recognized experts in BP monitoring from across the world and operates in affiliation with the European Society of Hypertension, the International Society of Hypertension, and the World Hypertension League. In the first stage, STRIDE BP has reviewed 419 validations of 260 devices and approved 69% of them, providing recommendations on accurate devices for office, ambulatory and home BP measurement in adults, children and during pregnancy. At the next stage, STRIDE BP intends to develop programs for on-line training and tools for use in clinical practice leading to improved measurement of BP and better diagnosis of hypertension world-wide.

Recent evidence indicates that both ambulatory blood pressure monitoring (ABPM) and home blood pressure monitoring (HBPM) are more useful than the measurement of office blood pressure for evaluating cardiovascular risks in subjects with hypertension. The major advantage of ABPM over HBPM is the ability to measure nighttime blood pressure and ambulatory blood pressure during the day. A newly developed, programmable HBPM device (HEM-5041, Omron Healthcare, [corrected] Kyoto, Japan) can record blood pressure up to 600 [corrected] times and measure nighttime blood pressure automatically. To validate the utility, feasibility, and safety of this device, we measured blood pressure by HBPM using HEM-5041 and by ABPM and compared the values in healthy volunteers. As compared with ABPM, daytime blood pressures, coefficients of variation for systolic blood pressure, diastolic blood pressure, and pulse rate, and the percentage nighttime fall in these variables were significantly lower with HBPM. However, nighttime blood pressures did not significantly differ between HBPM and ABPM. The results of a questionnaire survey indicated that the subjects were more comfortable when blood pressure was measured by HBPM than by ABPM, whereas the quality of sleep was similar. Our results suggest that HEM-5041 is useful for evaluating nighttime blood pressures as well as nighttime blood pressure falls, without causing clinically significant discomfort.

It is self-evident that accurate measurement of blood pressure (BP) is essential for the diagnosis and treatment of hypertension. Patients on hemodialysis typically do not have their BP measured under standardized conditions, a source of error in the assessment of their BP. However, their are some unique sources of error involving interdialytic weight gain, occurrence of sleep apnea and consequent nocturnal hypertension, inability to take BP in both arms in patients who have hemodialysis angioaccess in the arm, and the white coat effect in these patients as well. Precise measurement of BP in hemodialysis patients requires interdialytic ambulatory BP monitoring. However, when ambulatory BP monitoring is not possible, BP obtained in the dialysis unit can be used in a qualitative sense for prediction of hypertension in these patients. A 2-week average predialysis BP of greater than 150/85 mmHg or a postdialysis BP of greater than 130/75 mmHg has at least 80% sensitivity in diagnosing hypertension. Specificity of at least 80% can be achieved if predialysis BP of greater than 160/90 mmHg or postdialysis BP of greater than 140/80 mmHg are used. However, poor agreement between hemodialysis unit BP and ambulatory BP precludes their use for the precise prediction of BP. Improving measurement techniques in the dialysis unit, averaging multiple BP values, using 20-minute postdialysis readings, or home BP monitoring can improve BP determination when interdialytic BP monitoring is not possible.

The diagnosis and management of hypertension relies on accurate and precise blood pressure (BP) measurements and monitoring techniques. Variability in traditional office based BP readings can contribute to misclassification and potential misdiagnosis of hypertension, leading to inappropriate treatment and possibly avoidable adverse drug events. Both home blood pressure monitoring (HBPM) and 24-hour ambulatory blood pressure monitoring (ABPM) can improve characterization of BP status over traditional office values and can predict cardiovascular morbidity and mortality risk; however, they are limited by availability and/or practical use in many situations. Available in-office blood pressure measuring methods include manual auscultation, automated oscillometric, and automated office blood pressure (AOBP) devices. A strong correlation exists between AOBP and awake ABPM measurements and has been linked to better prediction of end-organ damage and white coat response compared to standard office BP methods. While AOBP does not provide nocturnal BP readings, it can be utilized in several outpatient settings, and has the capability to decrease utilization of ABPM, white coat effect, and improve optimization of cardiovascular assessment, evaluation, and therapeutic assessment in clinical practice.&#x0D; Hypertension affects over 80 million adults in the United States (US) and is a major risk factor for cardiovascular morbidity and mortality [1]. The condition’s ubiquitous nature and broad impact potentially makes understanding the diagnosis and treatment of hypertension key elements of managing cardiovascular risk. Though much attention is paid to the treatment of hypertension, from 2009 to 2012, 45.9% of US patients with hypertension were uncontrolled [1]. Appreciating the aspects of proper assessment of blood pressure is crucial and creates the foundation for approaching hypertension management. Until recently, hypertension was defined as an appropriately measured office systolic blood pressure (SBP) of greater than or equal to 140 mmHg and/or diastolic blood pressure (DBP) greater than or equal to 90 mmHg, with the patient seated and resting for 5 minutes in a proper position, and preferentially, measured as an average of two readings taken 1 or 2 minutes apart [1-5]. While serving as the primary method, standard office blood pressure assessment with either manual or traditional automated BP cuffs is limited in accuracy and application in everyday practice, and faces many challenges. As such, an understanding of the potential limitations of current BP strategies, and the roles and rationale for novel assessment techniques are of value to clinicians [6].&#x0D; Conflict of Interest: We declare no conflicts of interest or financial interests that the authors or members of their immediate families have in any product or service discussed in the manuscript, including grants (pending or received), employment, gifts, stock holdings or options, honoraria, consultancies, expert testimony, patents and royalties.&#x0D; &#x0D; Type: Review

Ambulatory and home blood pressure (BP) monitoring parameters are better predictors of cardiovascular events than are office BP monitoring parameters, but there is a lack of robust data and little information on heart failure (HF) risk. The JAMP study (Japan Ambulatory Blood Pressure Monitoring Prospective) used the same ambulatory BP monitoring device, measurement schedule, and diary-based approach to data processing across all study centers and determined the association between both nocturnal hypertension and nighttime BP dipping patterns and the occurrence of cardiovascular events, including HF, in patients with hypertension. This practitioner-based, nationwide, multicenter, prospective, observational study included patients with at least 1 cardiovascular risk factor, mostly hypertension, and free of symptomatic cardiovascular disease at baseline. All patients underwent 24-hour ambulatory BP monitoring at baseline. Patients were followed annually to determine the occurrence of primary end point cardiovascular events (atherosclerotic cardiovascular disease and HF). A total of 6,359 patients (68.6±11.7 years of age, 48% men) were included in the final analysis. During a mean±SD follow-up of 4.5±2.4 years, there were 306 cardiovascular events (119 stroke, 99 coronary artery disease, 88 HF). Nighttime systolic BP was significantly associated with the risk of atherosclerotic cardiovascular disease and HF (hazard ratio adjusted for demographic and clinical risk factors per 20-mm Hg increase: 1.18 [95% CI, 1.02-1.37], P=0.029; and 1.25 [95% CI, 1.00-1.55], P=0.048, respectively). Disrupted circadian BP rhythm (riser pattern, nighttime BP higher than daytime BP) was significantly associated with higher overall cardiovascular disease risk (1.48 [95% CI, 1.05-2.08]; P=0.024), and especially HF (2.45 [95% CI, 1.34-4.48]; P=0.004) compared with normal circadian rhythm. Nighttime BP levels and a riser pattern were independently associated with the total cardiovascular event rate, in particular for HF. These findings suggest the importance of antihypertensive strategies targeting nighttime systolic BP. Registration: URL: https://www.umin.ac.jp/ctr/; Unique identifier: UMIN000020377.

Automated office blood pressure (AOBP) using three to five measurements taken with an oscillometric device with or without an attendant in the room may decrease "white coat" effect, with a meta-analysis showing that average AOBP among a group of individuals is similar to daytime systolic and diastolic blood pressure (BP) obtained by 24-hour ambulatory BP monitoring (ABPM). 1 Based on these findings, AOBP has been recommended as a replacement to routine office BP measurements for both hypertension diagnosis and management.Furthermore, three recent landmark trials comparing lower systolic BP targets to standard treatment used AOBP to adjust BP medications and measure BP outcomes. [2][3]3][4] These studies all used validated oscillometric Omron BP monitors that could be set to wait 5 minutes and take 3 BP measurements one minute apart.US and international guidelines recommend proper patient preparation, cuff size, and positioning, and having individuals rest for at least 5 minutes prior to measuring BP and waiting at least 1 minute before measuring BP again. 5The AOBP protocol that has become most popular is to prepare the patient for BP measurement, use an oscillometric BP monitor that is pre-set to wait 5 minutes, then take 3 BP measurements 1 minute apart and average these, while having the attendant leave or quietly remain in the room.Unfortunately, this protocol takes about 10 minutes and requires the attendant to leave or wait to address other clinical issues until the measurements are completed.Busy clinic practices do not have an extra room or 10 minutes to spare.In this issue of the American Journal of Hypertension, Lynn-Green et al. 6 evaluated the accuracy of AOBP using shorter intervals of rest (3 minutes versus 5 minutes) and time between measurements (1 minute versus minute) with no significant difference in accuracy between methods.While findings were similar to other studies, 7,8 limitations included small sample size and lack of comparison to a reference standard.The authors concluded that shorter AOBP measurement protocols could improve AOBP adoption.Is shortened or standard AOBP time the secret sauce for improving hypertension (HTN) diagnosis and management?Below are reasons for being cautious about this claim and potential solutions:

Equipment, physiologic, and technique factors can influence the accuracy of blood pressure measurement. The current study was designed to isolate certain technique factors and then assess the accuracy of nursing personnel measurements of blood pressure in three residency family practice centers. An experienced registered nurse was trained in applying the American Heart Association recommendations for determining blood pressure by sphygmomanometry; three 1.5-hour practice sessions demonstrated her accuracy. Nine full days were then spent in the family practice centers rechecking as many staff blood pressure readings as possible while controlling for confounding variables. The following findings were significant: (1) the average absolute differences between control and study nurse systolic and diastolic blood pressure readings were 6.2 mmHg and 4.7 mmHg, respectively; (2) a unidirectional error of 3.8 mmHg in the measurement of diastolic blood pressure was found in one center, possibly because less care was taken with afternoon measurements; (3) variability in systolic blood pressure readings was higher in all three centers (+/- 8.5 mmHg) than attained during the training sessions for the control nurse (+/- 5.8 mmHg); (4) the average errors attributable to technique factors studied that were potentially correctable by training were only 1.8 mmHg for systolic and 0.7 mmHg for diastolic pressures. The degree of inaccuracy in ambulatory nursing blood pressure readings attributable to errors in technique is quantified by this study. Training can reduce, but not abolish, this inaccuracy. Careful attention to proper blood pressure measurement technique and such variables as equipment calibration is essential for both nursing and physician observers. Taking multiple blood pressure measurements before making clinical decisions can limit the effect of these inaccuracies.

Hypertension in children, not a “small” problem

Accurate blood pressure measurement is critical to successful clinical trials. Concerns about observer errors have led to the use of automated oscillometric devices without evidence that their performance is similar to that of trained observers. This study compares blood pressures obtained by trained observers and with an oscillometric device (Omron 705CP) to 24-h ambulatory blood pressure monitoring. We performed a post-hoc analysis of 313 untreated hypertensive patients at the end of the washout phase of a Novartis hypertension trial. Patients had three seated trained observer mercury auscultatory blood pressure measurements followed by 24-h ambulatory blood pressure monitoring. The next day, the ambulatory blood pressure monitoring was removed and three seated readings were obtained with an Omron 705CP. Correlations for systolic blood pressure and diastolic blood pressure were obtained between daytime ambulatory blood pressure monitoring (0900 and 2100) and the two office methods. In addition, we investigated the degree of difference of trained observer and Omron measurements from ambulatory blood pressure monitoring. For systolic blood pressure, the correlation with ambulatory blood pressure monitoring of the trained observer was significantly better than with that of the Omron 705CP (0.641 vs. 0.555, P=0.01). For diastolic blood pressure values, even greater disparity between the two office method correlations with ambulatory blood pressure monitoring was observed (trained observer=0.593 vs. Omron=0.319, P<0.0001). Both trained observer and Omron readings were consistently higher than ambulatory blood pressure monitoring for systolic blood pressure (P<0.0001) and diastolic blood pressure (P<0.0001). Omron measurements, however, deviated from ambulatory blood pressure monitoring more than those of the trained observer (P<0.0001 for systolic blood pressure and diastolic blood pressure). For clinical trials using diastolic blood pressure targets, the Omron 705CP cannot replace the auscultatory blood pressure measurements of a trained observer. For systolic blood pressure, the Omron device and the trained observer had similar correlations with ambulatory blood pressure monitoring; however, both methods gave consistently higher systolic blood pressure values. Further study of oscillometric devices should be conducted before universally replacing auscultatory blood pressure determinations by trained observers in clinical trials.

Working Group on Blood Pressure Monitoring of the European Society of Hypertension International Protocol for validation of blood pressure measuring devices in adults Eoin O’Brien,Thomas Pickering, Roland Asmar, Martin Myers, Gianfranco Parati, Jan Staessen, Thomas Mengden, Yutaka Imai, Bernard Waeber and Paolo Palatini and with the statistical assistance of Neil Atkins and William Gerin, on behalf of the Working Group on Blood Pressure Monitoring of the European Society of Hypertension

Imprecise blood pressure (BP) measurement may be responsible for inappropriate diagnosis and classification of hypertension, resulting in either excessive or insufficient use of antihypertensive drugs. On the background of the enormous impact of hypertension in terms of global disease burden, an accurate measurement and classification of BP levels becomes a fundamental step for the appropriate management of hypertensive patients. This chapter will provide an overview of the different methodologies currently available for BP measurement in the medical office, such as conventional office blood pressure (OBP) readings and unattended automated office blood pressure measurements (AOBP). It will also address techniques for BP measurement out of the doctor’s office such as 24 h ambulatory blood pressure monitoring (ABPM) and home blood pressure monitoring (HBPM), giving also practical recommendations for their implementation in clinical practice, based on current hypertension Guidelines. The chapter will also review the current definitions and classification of BP levels based on different BP measurement techniques, the abnormalities in 24 h BP patterns that can be identified through ABPM, and the different BP phenotypes that result from the discrepancies between office and out- of- office BP measurement techniques when used in combination (i.e. white coat hypertension and masked hypertension).