BpTRU Device Research Articles

In-office assessment of blood pressure in chronic kidney disease

The automated BpTRU device has been shown to improve the accuracy of in-office blood pressure assessment in hypertensive populations. We aimed to determine whether this was also true for patients with chronic kidney disease. We recorded the blood pressure of 80 hypertensive outpatients with chronic kidney disease by usual automated measurement and BpTRU automated measurement. We established whether there were any statistically significant differences in the absolute blood pressure values measured by either method and whether these differences had any impact on the assessment of blood pressure control. Systolic and diastolic blood pressures were significantly lower by BpTRU measurement than by usual measurement, by 10.1±12.2 mmHg (95% confidence interval: 7.4-12.8 mmHg, P<0.001) and 2.8±10.6 mmHg (95% confidence interval: 0.4-5.1 mmHg, P=0.02), respectively. Significantly, more patients achieved their blood pressure target of 130/80 mmHg or less by BpTRU measurement than by usual measurement (72.5 vs. 48.8% for systolic blood pressure, P<0.001; 68.8 vs. 61.3% for diastolic blood pressure, P=0.02). Systolic blood pressures remained significantly lower by BpTRU measurement than by usual measurement in all predefined study subgroups (estimated glomerular filtration rate <30 vs ≥30 ml/min/1.73m; transplant vs. nontransplant). We detected more hypotension by BpTRU measurement than by usual measurement. Our study suggests that the BpTRU device can negate white coat effect in patients with chronic kidney disease. The use of this device in routine clinical practice could improve the overall accuracy of in-office blood pressure assessment in this high-risk population, minimizing the potential for undertreatment and overtreatment of hypertension.

Conventional versus automated measurement of blood pressure in primary care patients with systolic hypertension: randomised parallel design controlled trial

Objective To compare the quality and accuracy of manual office blood pressure and automated office blood pressure using the awake ambulatory blood pressure as a gold standard.Design Multi-site cluster randomised...

Can sphygmomanometers designed for self-measurement of blood pressure in the home be used in office practice?

To examine the possibility of measuring automated office (AO) blood pressure (BP) using home BP recorders in place of the more expensive, fully automated devices designed specifically for professional use. Three groups of 100 patients each had five AOBP readings recorded with one of three home BP devices while resting alone in a quiet examining room. These devices were also used to obtain 24 home BP readings during 6 days. Five AOBP readings were also recorded using the BpTRU device and all patients had 24-h ambulatory BP and manual BP readings taken. Mean systolic AOBP was within 3-4 mmHg of the mean awake ambulatory BP for each of the three home BP recorders whether used in the office setting or at home. Diastolic readings tended to be higher than the corresponding awake ambulatory BP. For the 139 patients with hypertension, mean (±standard deviation) AOBP taken with the home BP devices (146±14/86±12) was higher (P<0.001) than the awake ambulatory BP (142±11/81±12) and AOBP taken with the BpTRU device (141±15/82±12). Systolic BP at home (142±14/85±10) was also similar to the awake ambulatory BP but diastolic BP was higher (P<0.001). There were no significant differences in correlation coefficients between each set of AOBP readings and awake ambulatory BP. Home BP devices may be used to record AOBP in selected patients. However, a fully automated sphygmomanometer is still the device of choice for obtaining AOBP readings similar to the awake ambulatory BP in patients with suspected hypertension.

Manual and automated office measurements in relation to awake ambulatory blood pressure monitoring

Automated blood pressure (BP) devices are commonly used in doctor's offices. How BP measured on these devices relates to ambulatory BP monitoring is not clear. To assess how well office-based manual and automated BP predicts ambulatory BP. Using data on 654 patients, we assessed how well sphygmomanometer measurements and measurements taken with an automated device (BpTRU) predicted results on ambulatory BP monitoring. We assess positive and negative predictive values and overall accuracy. We look at different cut-points for systolic (130, 135 and 140 mmHg) and diastolic (80, 85 and 90 mmHg) BP. A single automated office BP (AOBP) assessment provides superior predictive values and overall accuracy compared to three manual office BP assessments. For systolic BP, the predictive values are ≤69% for any of the cut-points while the positive predictive values for the single automated measurement is between 80.0% and 86.9% and the overall accuracy gets as high as 74% for the 130 mmHg cut-point. For diastolic BP, the automated readings are also more predictive but in this case, it is the negative predictive values that are better, as well as the overall accuracy. Based on the results, we suggest that 135/85 mmHg continue to be used as the cut-point defining high BP with the BpTRU device. However, future research might suggests that values in a grey zone between 130-139 mmHg systolic and 80-89 mmHg diastolic be confirmed using ambulatory BP monitoring. As well, three AOBP assessments might produce much greater accuracy than the single AOBP assessment used in the study.

CAN PATIENT-ACTIVATED HOME BLOOD PRESSURE RECORDERS ELIMINATE THE WHITE COAT RESPONSE IF USED IN A CLINICAL SETTING?: PP.3.115

Objective: Automated office (AO) BP obtained using fully automated devices which record multiple readings with the patient resting alone in a quiet room has been shown to virtually eliminate the white coat response with readings similar to the awake ambulatory (AA) BP. This study examined the possibility of replacing fully automated devices such as the BpTRU with relatively inexpensive, validated, patient-activated home (H) BP recorders. Methods: AABP was compared with AOBP readings in patients with predominantly systolic hypertension referred for 24-hour ambulatory BP monitoring. AOBP was obtained using the fully automated BpTRU device (mean of five readings) and using one of three different HBP recorders (A&D UA787, Microlife A 100 plus and Omron HEM 780E) to obtain a mean of five patient-activated readings (HBP-O). Each patient also used the same HBP recorder to obtain 28 readings in the home (HBP-28) and had 24-hour ambulatory BP monitoring performed using a Spacelabs 90207 device. Results: One hundred and thirty-nine patients (mean age 63, range 18–86 years; 61 M, 78 F; 58 untreated) with a manual systolic BP (mmHg) >/ = 140 (mean ± SD BP 152 ± 9/84 ± 12) were studied. Mean values for AABP, fully automated BpTRU, patient-activated HBP-O and HBP-28 home readings were as follows: 142 ± 11/81 ± 12, 141 ± 14/82 ± 12, 146 ± 14/86 ± 12 and 142 ± 14/85 ± 10, respectively. Patient-activated readings using an HBP recorder under similar conditions to readings taken with the BpTRU gave systolic BP readings which were 4–5 mmHg higher (p < 0.001) than the AABP, BpTRU and HBP-28. AABP correlated significantly (p< 0.001) with AOBP readings taken with the BpTRU (r = 0.40 / r = 0.83), HBP-O (r = 0.44 / r = 0.79), and HBP-28 (r = 0.57 / r = 0.87). Conclusion: AOBP recorded with a fully automated device (BpTRU) eliminates the white coat response with readings similar to the AABP. Patient-activated AOBP taken with a standard HBP recorder reduces but does not eliminate the white coat response since the systolic BP was still significantly higher than with the AABP, home BP and fully automated AOBP using the BpTRU.

A primary care pragmatic cluster randomized trial of the use of home blood pressure monitoring on blood pressure levels in hypertensive patients with above target blood pressure

The measurement of blood pressure (BP) at home by patients with hypertension is increasingly used to assess and monitor BP. Evidence for its effectiveness in improving BP control is mixed. To determine if home BP monitoring improves BP a pragmatic cluster randomized contolled trial was carried out in family practices in southeastern Ontario, Canada. Family practice patients with uncontrolled hypertension were recruited to the trail. Patients were divided into two groups: one with at least weekly measurements of BP at home, recording those measurements and showing those to the family physician during office visits for hypertension and the control group were given usual care. The primary outcome was mean awake BP on ambulatory monitoring at 6- and 12-month follow-up and the secondary outcomes were mean BP on full 24-hour ambulatory blood pressure monitoring (ABPM), mean sleep BP on ABPM and BP on the BpTRU device, all at 6- and 12-month follow-up. Home BP monitoring did not improve BP compared to usual care at 12-month follow-up: mean awake systolic BP on ABPM [141.1 versus 142.8 mmHg, mean difference 1.7 mmHg; 95% confidence interval (CI) -0.6 to 4.0, P = 0.314] and mean awake diastolic BP on ABPM (78.7 versus 79.4 mmHg, mean difference 0.7 mmHg; 95% CI -7.7 to 9.1, P = 0.398). Similar negative results were obtained for men and women separately. However, outcomes using the full 24-hour ABPM and the BpTRU device showed a significantly lower diastolic BP at 12 months. When analysis was done by sex, this effect was shown to be only in men. Home BP monitoring may improve BP control in men with hypertension.

Use of automated office blood pressure measurement to reduce the white coat response

To examine the possibility of reducing the white coat response using an automated sphygmomanometer designed for office use, the BpTRU. Consecutive patients referred from physicians in the community to an ambulatory blood pressure (ABP) monitoring unit in an academic hospital were included in the study. A total of 309 patients referred for diagnosis or management of hypertension were studied. Differences between mean awake ABP and BP readings taken by the patient's own physician using a manual sphygmomanometer or the automated BpTRU device with the patient resting alone in the ABP monitoring unit were compared. BP recorded in the examining room using an automated device (132 +/- 19/75 +/- 12) was similar to the mean awake ABP (134 +/- 12/77 +/- 10) with both values being lower (P < 0.001) than the BP recorded on a routine visit to the patient's own family physician (152 +/- 18/87 +/- 11). The coefficient of correlation between the systolic/diastolic ABP and the automated office BP (r = 0.62/0.72) was higher (P < 0.001) than with the family physician's manual BP (r = 0.32/0.48). The prevalence of white coat hypertension in untreated patients (n = 146) was significantly (P < 0.001) lower with automated office BP (16%) compared with the routine family physician BP (55%). The white coat response associated with office BP measurements can be virtually eliminated by recording BP with the automated BpTRU device with patients resting alone in a quiet examining room.

Blood pressure variability and prevalence of hypertension using automated readings from multiple visits to a pharmacy-based community-wide programme

Blood pressure (BP) measurements taken outside the routine office context may be a useful adjunct strategy to monitor BP. Community-based BP data can also provide estimates of the prevalence of elevated BP. We compared multiple readings taken on different days in pharmacies using an automated BpTRU device during a cardiovascular health programme targeting community-dwelling older adults. Mean systolic (S) and diastolic (D) BP values were compared over time using repeated measures analysis of variance for all participants with at least three separate sets of readings (n=317). BP variability was then examined among four subgroups based on report of antihypertensive medication or no treatment, and normal or elevated SBP at the initial visit (< or >or=140, or 130 if diabetes reported). Prevalence of elevated BP was compared across visits. Overall, mean SBP decreased between visits 1 and 2 (140.4 vs 137.1 mm Hg; P<0.001). Among participants with normal SBP at the initial visit, SBP did not vary significantly, whether or not antihypertensive treatment was reported. Those with initially elevated SBP experienced a significant decrease between visits 1 and 2, also regardless of treatment status. Prevalence of elevated BP decreased from visits 1 to 2 (55.8 vs 48.9%; P=0.026) and from visits 1 to 3 (55.8 vs 42.9%; P<0.001). Analyses of BP data from a community-based programme using an accurate device showed that initial readings may inflate the population estimate of elevated BP. Findings suggest that more than one set of BP readings measured on different occasions are needed, particularly if the first set is elevated.

Optimum frequency of office blood pressure measurement using an automated sphygmomanometer

To determine the optimum interval between serial blood pressure measurements using an automated BpTRU sphygmomanometer. Two groups of 200 patients each had automated office measurements taken using the BpTRU device at either 1-min or 2-min intervals from the start of one reading to the start of the next reading with a 24-h ambulatory blood pressure (ABP) recording being performed. Another series of 50 patients had BpTRU readings taken at 1-min and 2-min intervals before and after 24-h ABP monitoring. The difference between the mean awake ABP and the mean automated office BP readings were compared for recordings taken at 1-min versus 2-min intervals. In the between-patient comparison (n=400), mean awake ABP was similar to automated BP recordings in the examining room at either 1-min or 2-min intervals except for a slightly lower (-4 mmHg) diastolic BP with the 1-min interval (P<0.01 vs. ABP). In the within-patient comparison (n=50), there was no consistent difference between automated BP readings taken in the examining room at 1-min versus 2-min intervals. Overall, the mean automated BP values tended to be slightly lower than the mean awake ABP. Automated measurement of BP in the office setting with devices such as the BpTRU can be taken as frequently as every 1 min without affecting the accuracy of the reading. Small differences in BP between the 1 and 2-min settings and between the automated BpTRU and ABP readings were within accepted clinical standards for validation criteria.

Comparison Between an Automated and Manual Sphygmomanometer in a Population Survey

An automated sphygmomanometer, the BpTRU, was used in a blood pressure (BP) survey of 2,551 residents in the province of Ontario. Automated BP readings were compared with measurements taken by a mercury sphygmomanometer under standardized conditions in a random 10% sample. BP was recorded in 238 individuals in random order using both a standard mercury device and an automated BP recorder, the BpTRU. All subjects rested for 5 min prior to the first BP reading, which was then discarded. The mean of the next three readings was obtained using the mercury device whereas the BpTRU was set to record a mean of five readings taken at 1 min intervals with subjects resting alone in a quiet room. The mean s.d. BP with the automated device was 115 +/- 16/71 +/- 10 mm Hg compared to 118 +/- 16/74 +/- 10 mm Hg for the manual BP (P < 0.001). A systolic BP > or = 140 mm Hg was present for 16 automated and 19 manual readings. Similarly, the diastolic BP was > or = 90 mm Hg for 9 automated and 14 manual readings. Linear regression analysis showed that automated BP was a significant (P < 0.001) predictor of both manual systolic and diastolic BP. Conventional manual BP readings can be replaced by readings taken using a validated, automated BP recorder in population surveys. The slightly lower readings obtained with the BpTRU device (in the context of reduced observer-subject interaction) may be a more accurate estimate of BP status.

The BpTRU automatic blood pressure monitor compared to 24 hour ambulatory blood pressure monitoring in the assessment of blood pressure in patients with hypertension

BackgroundIncreasing evidence suggests that ABPM more closely predicts target organ damage than does clinic measurement. Future guidelines may suggest ABPM as routine in the diagnosis and monitoring of hypertension. This would create difficulties as this test is expensive and often difficult to obtain. The purpose of this study is to determine the degree to which the BpTRU automatic blood pressure monitor predicts results on 24 hour ambulatory blood pressure monitoring (ABPM).MethodsA quantitative analysis comparing blood pressure measured by the BpTRU device with the mean daytime blood pressure on 24 hour ABPM. The study was conducted by the Centre for Studies in Primary Care, Queen's University, Kingston, Ontario, Canada on adult primary care patients who are enrolled in two randomized controlled trials on hypertension. The main outcomes were the mean of the blood pressures measured at the three most recent office visits, the initial measurement on the BpTRU-100, the mean of the five measurements on the BpTRU monitor, and the daytime average on 24 hour ABPM.ResultsThe group mean of the three charted clinic measured blood pressures (150.8 (SD10.26) / 82.9 (SD 8.44)) was not statistically different from the group mean of the initial reading on BpTRU (150.0 (SD21.33) / 83.3 (SD12.00)). The group mean of the average of five BpTRU readings (140.0 (SD17.71) / 79.8 (SD 10.46)) was not statistically different from the 24 hour daytime mean on ABPM (141.5 (SD 13.25) / 79.7 (SD 7.79)). Within patients, BpTRU average correlated significantly better with daytime ambulatory pressure than did clinic averages (BpTRU r = 0.571, clinic r = 0.145). Based on assessment of sensitivity and specificity at different cut-points, it is suggested that the initial treatment target using the BpTRU be set at <135/85 mmHG, but achievement of target should be confirmed using 24 hour ABPM.ConclusionThe BpTRU average better predicts ABPM than does the average of the blood pressures recorded on the patient chart from the three most recent visits. The BpTRU automatic clinic blood pressure monitor should be used as an adjunct to ABPM to effectively diagnose and monitor hypertension.