[Prospective evaluation of the hyperbaric-tolerance test for the diagnosis of gestational hypertension and preeclampsia].
OBJECTIVE
Recent studies have tried to overcome poor results from isolated blood pressure values in detecting hypertension in pregnancy by relying on ambulatory monitoring. Low sensitivity of the 24-hour mean has led many authors to conclude that ambulatory monitoring is not a valid approach in pregnancy. Against this background, we have evaluated prospectively the sensitivity and specificity in the diagnosis of gestational hypertension of the tolerance-hyperbaric test. This is a combined approach consisting of establishing tolerance intervals for the circadian variability of blood pressure as a function of gestational age, and then computing the hyperbaric index (area of blood pressure excess above the upper limit of the interval) by comparison of any patient's blood pressure profile with those limits.


METHODS
We studied 328 women who provided a 2014 blood pressure series. They were sampled for 48 hours once every 4 weeks from the first obstetric visit (mostly within the first trimester of gestation) until delivery. The hyperbaric index of each blood pressure series was calculated by taking into account the reference circadian tolerance limits established from a 497 series previously sampled from an independent reference group of 189 normotensive pregnant women.


RESULTS
Sensitivity of the tolerance-hyperbaric test was 91% for women sampled during the first trimester of gestation, and increased up to 99% in the third trimester. Specificity was above 99% in all trimesters. Positive and negative predictive values were above 96% in all trimesters. Moreover, the hyperbaric index provided an early identification of subsequent gestational hypertension and preeclampsia, on the average of 23 weeks prior to the clinical confirmation of the disease.


CONCLUSIONS
The tolerance-hyperbaric test represents a reproducible, stable, noninvasive, and high sensitivity test for the very early identification of subsequent gestational hypertension and preeclampsia, which can also be used as a guide for establishing prophylactic or therapeutic interventions.
Hermida
Ramón C
RC
Laboratorio de Bioingeniería y Cronobiología, Universidad de Vigo, Vigo, Pontevedra, Spain. rhermida@tsc.uvigo.es
Ayala
Diana E
DE
Fernández
José R
JR
Mojón
Artemio
A
Iglesias
Manuel
M
D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory / Q000379:methods*; D005260:Female; D005865:Gestational Age; D006801:Humans; D006973:Hypertension / Q000175:diagnosis*; D011225:Pre-Eclampsia / Q000175:diagnosis*; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000175:diagnosis*; D011446:Prospective Studies; D012680:Sensitivity and Specificity