Blood Pressure Excess for the Early Identification of Gestational Hypertension and Preeclampsia

Abstract

Abstract-We have examined prospectively whether the combined approach of establishing tolerance intervals for the circadian variability of blood pressure (BP) as a function of gestational age, and then determining the so-called hyperbaric index (area of BP excess above the upper limit of the tolerance interval) by comparison of any patient's BP profile (obtained by ambulatory monitoring) with those intervals provides a high sensitivity test for the early detection of pregnant women who subsequently will develop gestational hypertension or preeclampsia. We analyzed 657 BP series from 92 women with uncomplicated pregnancies and 378 series from 60 women who developed gestational hypertension or preeclampsia. BP was sampled for about 48 hours once every 4 weeks after the first obstetric consultation. Circadian 90% tolerance limits were determined as a function of trimester of gestation from 497 series previously sampled from a reference group of 189 normotensive pregnant women. The hyperbaric index was then determined for each individual BP series in the validation sample. Sensitivity of this test for diagnosing gestational hypertension was 93% for women sampled during the first trimester of gestation and increased up to 99% in the third trimester. The positive and negative predictive values were above 96% in all trimesters. Despite the limitations of ambulatory monitoring, the approach presented here, now validated prospectively, represents a reproducible, noninvasive, and high sensitivity test for the very early identification of subsequent gestational hypertension and preeclampsia, on the average, 23 weeks before the clinical confirmation of the disease. Key Words: Ⅲ blood pressure Ⅲ diagnostic test Ⅲ tolerance intervals Ⅲ hyperbaric index Ⅲ human pregnancy Ⅲ normotension Ⅲ hypertension, gestational Ⅲ preeclampsia I n order to predict the occurrence of gestational hypertension or even preeclampsia, several (clinical, biochemical, and biophysical) tests have been designed with various degrees of specificity and sensitivity.1 Gant et al 2 proposed the roll-over or supine pressor test for predicting the development of acute hypertension in pregnancy. The results of this test are highly variable among different investigators, and there is poor reproducibility in the same patient.1 Therefore, although the roll-over test has gained some popularity because of its simplicity, it is of little use clinically as a predictive test. Intravenous infusion of angiotensin II was reported to cause a smaller rise in BP in pregnant women than in nonpregnant women.3 These results were complemented by the finding that the relative refractoriness to the pressor effects of angiotensin II is lost to a marked extent in women who subsequently developed preeclampsia. [4][5][6] As for the roll-over test, sensitivity and specificity of the angiotensin II test varied greatly among different studies. Moreover, this test is too complicated and time consuming to be used as a clinical screening procedure. 1Because an elevated BP is the hallmark fo...

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

“…While all these studies are based on ABPM done for 24 hours only, the most extended conclusion so far is that due to poor results in the diagnostic test based on the BP mean, ABPM does not provide a proper approach for the early identification of preeclampsia, and it should not be used in pregnancy. 11 Against the common approach of relying on the 24-hour mean of ABPM, the combined approach of establishing tolerance intervals for the circadian variability of BP as a function of gestational age 25 and then computing the hyperbaric index (area of BP excess above the upper limit of the tolerance interval) by comparison of any patient's BP profile with those intervals, has been shown to provide high sensitivity and specificity for the early detection of pregnant women who will have subsequent development of gestational hypertension or preeclampsia 12 as well as a proper approach for the prediction of the outcome of pregnancy. 26 Results from this trial on the impact of the duration and frequency of BP sampling on the reproducibility of mean values indicate that parameters calculated from the ABPM profile are much more dependent on duration of sampling than on sampling rate.…”

“…10 Hypertensive patients, including women with gestational hypertension or preeclampsia, appear to have a greater day-to-day variability in BP than normotensive subjects. 23 Although most studies assessing the circadian BP profile have used 24-hour ABPM, as a compromise with practicality, monitoring over at least 48 hours has been shown to present advantages in the analysis of BP variability, 23,39 diagnosis of disease, 12,40 and evaluation of a patient's response to treatment. 39,40 The individualized estimation of rhythm characteristics become more reliable; new end points are obtained, such as the circadian period, which cannot usually be estimated from 24-hour records.…”

“…Gestational hypertension was defined as conventional BP values Ͼ140 or 90 mm Hg for systolic (SBP) or diastolic BP (DBP), respectively, after the 20th week of gestation, and/or a hyperbaric index (area of BP excess above the upper limit of a time-varying tolerance interval 25,26 ) consistently above the threshold for diagnosis of hypertension in pregnancy 12 after the 20th week of gestation for further corroboration. Preeclampsia was defined as gestational hypertension and proteinuria Ͼ300 mg in 24 hours of urine collection.…”

Baroreflex sensitivity, heart rate, and blood pressure variability in hypertensive pregnancy disorders

“…1,[10][11][12] Our research group showed first that HRV, BPV, and BRS are not changed in the second and third trimester in normal pregnancy. 10 In PIH and PE, an increased HRV and BPV, [13][14][15][16] and a decreased BRS 12 were described compared to healthy pregnant women, whereas other groups described no differences in those variability parameters in pre-eclamptic pregnancies. 17 The purpose of this study was to evaluate whether HRV, BPV, and BRS are different between various hypertensive disorders and in comparison to normal pregnancies.…”

Evaluation of the Blood Pressure Load in the Diagnosis of Hypertension in Pregnancy

“…Key Words: pregnancy Ⅲ preeclampsia Ⅲ blood pressure monitoring, ambulatory Ⅲ hypertension, pregnancy R ecent studies have tried to overcome the poor results from isolated blood pressure (BP) measurements in detecting hypertensive complications in pregnancy 1,2 by relying on ambulatory BP monitoring (ABPM). [3][4][5][6][7][8] Using this approach, a predictable trend of BP variation along pregnancy was demonstrated for normotensive pregnant women systematically monitored every 4 weeks from the first trimester of pregnancy until delivery. The trend of decreasing BP up to the middle of gestation followed by increasing BP up to the day of delivery could not be found in pregnancies complicated with gestational hypertension or preeclampsia.…”