Sampling requirements for ambulatory blood pressure monitoring in the diagnosis of hypertension in pregnancy

Abstract

Abstract-Previous studies on ambulatory blood pressure monitoring as a potential screening test for hypertension in pregnancy have not carefully considered sampling requirements. We have examined the impact of duration and frequency of blood pressure sampling in the reproducibility of mean values in pregnancy. We analyzed 2430 blood pressure series sampled every 20 minutes during the day and every 30 minutes at night for 48 hours every 4 weeks from the first obstetric visit until delivery in 235 normotensive and 168 hypertensive pregnant women. Blood pressure series were decimated to generate shorter series with data sampled every 1, 2, 3, or 4 hours for 48 hours, as well as at the original rate for the first day. Reproducibility of mean blood pressure as well as sensitivity and specificity in the diagnosis of hypertension were compared between the original and the decimated series. Sensitivity and specificity of the 24-hour blood pressure mean are similar for the values calculated from the original series and for those obtained from shorter profiles up to data sampled every 3 hours but reduced by 5% to 12% when diagnosis is based on data sampled at 20-to 30-minute intervals for the first 24 hours. Results also indicate that the 24-hour blood pressure mean is better reproduced with data sampled at 3-hour intervals for 48 hours than by data sampled at 20-to 30-minute intervals for 1 day only. This study demonstrates that reproducibility of mean blood pressure values is more dependent on duration of sampling than on sampling rate. Key Words: blood pressure Ⅲ pregnancy Ⅲ hypertension, pregnancy Ⅲ preeclampsia Ⅲ blood pressure monitoring, ambulatory P regnancies complicated by hypertension contribute markedly to perinatal morbidity and mortality rates. 1 Because an elevated blood pressure (BP) after 20 weeks of gestation in a previously normotensive woman is common to the definition of both gestational hypertension and preeclampsia, 2,3 the issue of whether the development of these complications may be predicted on the basis of BP obtained during conventional antenatal visits has been addressed in several retrospective as well as prospective studies. 4 -7 Recent studies have tried to overcome the poor results from isolated conventional BP measurements in detecting hypertensive complications in pregnancy by relying on ambulatory BP monitoring (ABPM). 8 -17 By the use of ABPM, differences between healthy and complicated pregnancies in the circadian pattern of BP, previously documented for the second trimester of pregnancy, 9 can be observed as early as in the first trimester of pregnancy, quite before the actual clinical diagnosis of gestational hypertension or preeclampsia takes place for most pregnant women investigated. 15,17 As in the general nonpregnancy practice, the most common approach has been to rely for diagnosis on the arithmetic mean of all values determined by ABPM. However, the use of the 24-hour mean of BP does not provide a proper approach for an individualized early diagnosis of hypertension in pr...

2013 Ambulatory Blood Pressure Monitoring Recommendations for the Diagnosis of Adult Hypertension, Assessment of Cardiovascular and other Hypertension-associated Risk, and Attainment of Therapeutic Goals

“…Thus, most past studies have not evaluated the impact of the duration of ABPM on the reproducibility of results. Along these lines, the findings of previous studies have already documented advantages of extending the duration of ABPM from 24 to ≥48 h in terms of the reproducibility of derived clinical parameters (Hermida & Ayala, 2003;Hermida et al, 2002bHermida et al, , 2007cHermida et al, , 2013dMochizuki et al, 1998;Tamura et al, 1990). In summary, these studies have consistently documented the reproducibility of BP characteristics, including mean BP values and sleep-time relative BP decline (measure of BP dipping), depends markedly on the duration, and to a much lesser extent on the frequency, of BP sampling.…”

“…Sampling Rate and Duration of ABPM Most past ABPM patient studies were performed with measurements gathered every 15 to 60 min over a single 24-h span, mainly using mean BP values as criteria to diagnose hypertension (Chobanian et al, 2003;Head et al, 2012;Mancia et al, 2007;Pickering et al, 2005) and assess hypertension therapy (Waeber & Brunner, 1999). In actuality, the sampling requirements for ABPM have only been occasionally addressed (Enström & Pennert, 2001;Hermida & Ayala, 2003;Hermida et al, 2007cHermida et al, , 2013d. Previous reports have documented the expected increased reproducibility of mean BP values associated with the increased number of BP measurements per 24 h, i.e., greater sampling rate (Mancia et al, 1994).…”

Optimal timing for antihypertensive dosing: focus on valsartan

“…The advantages of 48 h sampling, instead of the most common 24 h ABPM, in terms of reproducibility of results and classification have been documented previously ( Mochizuki et al 1998 ; Hermida et al 2002a , 2002c). Uncertainty in the classification of a patient as dipper may be reduced from 42% to just 6% by expanding monitoring from 24 h to 48 h ( Hermida et al 2002b ), as the proper estimation of mean BP values is more dependent on duration of monitoring than on sampling rate ( Hermida and Ayala 2003 ).…”

Association of three different techniques to measure blood pressure in the first trimester with the development of hypertensive disorders of pregnancy

“…Blood pressure was measured every 30 minutes between 06.00 and 00.00 hours and every 60 minutes between 00.00 and 06.00 hours. All women started the measurements between 07.00 and 12.00 hours and continued for 48 consecutive hours (16). The participants were instructed to maintain their daily routine.…”