Impact of 30- Versus 60-Second Time Intervals Between Automated Office Blood Pressure Measurements on Measured Blood Pressure

Guidelines recommend 1 to 2 minutes between repeated, automated office-based blood pressure (AOBP) measures, which is a barrier to broader adoption. Patients from a single hypertension center underwent a 3-day evaluation that included a 24-hour ambulatory blood pressure (BP) monitor (ABPM) and one of two nonrandomized, unattended AOBP protocols. Half of the patients underwent 3 AOBP measurements separated by 30 seconds, and the other half underwent 3 BP measurements separated by 60 seconds. All measurements were compared with the average awake-time BP from ABPM and the first AOBP measurement. We used linear regression to assess whether the 30-second protocol was associated with individual or average AOBP measurements or awake-time ABPM and used an interaction term to determine whether interval modified the relationship between AOBP measurements (individual and mean) with awake-time ABPM. Among 102 patients (mean age, 59.2±16.2 years; 64% women; 24% Black), the average awake-time BP was 132.5±15.6/77.7±12.2 mm Hg among those who underwent the 60-second protocol and 128.6±13.6/76.5±12.5 mm Hg for the 30-second protocol. Mean systolic/diastolic BP was lower with the second and third AOBP measurement by −0.5/−1.7 mm Hg and −1.0/−2.3 mm Hg for the 60-second protocol versus −0.8/−2.0 mm Hg and −0.7/−2.7 mm Hg for the 30-second protocol; protocol did not significantly modify these differences. Differences between AOBP measurements (first, second, or third) and awake-time ABPM were nearly identical across protocols. In conclusion, a 30-second interval between AOBP measurements was as accurate and reliable as a 60-second interval. These findings support shorter time intervals between BP measurements, which would make AOBP more feasible in clinical practice.

Abstract P124: Repeat Manual Office Blood Pressure By A Physician Is Lower Than Automated Office Blood Pressure

Introduction: An accurate measurement of blood pressure (BP) is critical to diagnosing and treating hypertension (HTN). Manual office BP (MOBP) often results in higher readings than automated office BP (AOBP). In previous studies, a repeat MOBP by a physician resulted in a lower BP than the initial MOBP by nursing staff. We evaluated our hypothesis that a repeat MOBP by a physician is statistically equivalent to AOBP. Methods: In an ambulatory outpatient setting, patients were roomed and at least a 5-minute interval lapsed before an AOBP was performed using a Welch Allyn Connex Vital Signs Monitor. The physician was blinded to the AOBP. The physician then entered the room and obtained a MOBP with a manual aneroid sphygmomanometer. The difference between the AOBP and the MOBP was calculated. A Wilcoxon signed rank sum test was used to determine if a significant difference between AOBP and MOBP exists. Results: A total of 186 patients (112 females, 74 male) had BP measured with a mean age of 66 years. AOBP resulted in a median systolic BP (SBP) 136 mmHg (IQR 121-150 mmHg) and median diastolic BP (DBP) of 78 mmHg (IQR 72-85 mmHg). MOBP SBP had a median of 132 mmHg (IQR 120-142 mmHg) and DBP had a median of 76 mmHg (IQR 70-81 mmHg). SBP and DBP were significantly lower in the MOBP group with a mean difference between AOBP and MOBP of 4.0 and 2.7 mmHg respectively (p-value of <0.0001). Conclusions: Repeat MOBP performed by the physician resulted in a significantly lower BP compared to AOBP. The lower BP may be due to an overall longer interval between the AOBP measurement and MOBP measurement. MOBP may be a viable option for accurate diagnosis and treatment of HTN clinics without access to a AOBP machine.

Abstract MP71: Impact Of 30 Versus 60 Second Time Interval Between Automated Office Blood Pressure Measurements On Measured Blood Pressure

Background: Guidelines advocate for the use of automated office-based blood pressure (AOBP) measurement to improve accuracy of blood pressure (BP) measurement in the outpatient clinical setting. Current recommendations include a 5-minute period of quiet rest prior to obtaining 3 readings, each separated by 1-2 minutes. As a result, AOBP requires a minimum of 7 minutes of rest time in addition to proper patient positioning plus cuff inflation and deflation, adding nearly 10 minutes to an office visit. Reducing this by even 1 minute has broad implications for the widespread use of AOBP. Methods: Patients from a single hypertension center underwent a 3-day evaluation that included a 24-hour ambulatory BP monitor (ABPM) and one of two, non-randomized, unattended AOBP protocols. Half of patients underwent 3 BP measurements separated by 30 seconds and the other half underwent 3 BP measurements separated by 60 seconds. All measurements were compared to the average awake-time BP from ABPM as well as the first AOBP measurement. Results: Among 102 patients, the average awake-time BP was 128.6±13.6/76.5±12.5 mmHg for the 30-second protocol and 132.5±15.6/77.7±12.2 mmHg among those who underwent the 60-second protocol . Mean BP was lower with the 2nd and 3rd AOBP measurement by -0.5/-1.7 mmHg and -1.0/-2.3 mmHg for the 60-second protocol versus -0.8/-2.0 mmHg and -0.7/-2.7 mmHg for the 30-second protocol ( Figure ). Differences between AOBP measurements (1st, 2nd, or 3rd) and awake-time ABPM were nearly identical across protocols. Conclusion: A 30-second interval between AOBP measurements was as accurate and reliable as a 60-second interval.

Clinical Impact of after-consult clinic blood pressure: comparison with automated office blood pressure

Background It is most important to measure blood pressure (BP) exactly in treating hypertension. Recent recommendations for diagnosing hypertension clearly acknowledge that an increase in BP attributable to the “whitecoat response” is frequently associated with manual BP recordings performed in community-based practice. However, there was no data about after-consult (AC) BP that could reduce whitecoat effect. So we evaluated before-consult (BC) and AC routine clinic BP and research based automated office blood pressure (AOBP) measured. Methods The study population consisted of 82 consecutive patients with hypertension between April 2019 and December 2019. We measured routine clinic BP and AOBP before and after see a doctor, respectively. Seated blood pressure and pulse are measured at each time after a rest period using an automated device as it offers reduced potential for observer biases. AOBP was measured and measuring BP 3 times un-observed. We compared each BP parameter for identifying exact resting BP state. Results There was significant difference between BC and AC systolic BP (135.37 ± 16.90 vs. 131.95 ± 16.40 mmHg, p = 0.015). However there was no difference in the BC and AC diastolic blood pressure (73.75 ± 11.85 vs. 74.42 ± 11.71 mmHg, p = 0.415). In the AOBP comparison, there was also significant difference (BC systolic AOBP vs. AC systolic AOBP, 125.17 ± 14.41 vs. 122.98 ± 14.09 mmHg, p = 0.006; BC diastolic ABOB vs. AC diastolic AOBP, 71.99 ± 10.49 vs. 70.99 ± 9.83, p = 0.038). Conclusions In our study, AC AOBP was most lowest representing resting state. Although AC BP was higher than BC AOBP, it might be used as alternative measurement for reducing whitecoat effect in the routine clinical practice.