my personal edition > hypertension > news


  E-Mail this DGDispatch to a colleague

DGDispatch

Ambulatory Blood Pressure Test Identifies Risk For Preeclampsia As Early As First Trimester: Presented at AHA-HBPR

By Peggy Peck
Special to DG News

ORLANDO, FL -- September 27, 2002 -- A novel software program coupled with 48-hour ambulatory blood pressure monitoring correctly identified 93 percent of women at risk for preeclampsia in the first trimester of pregnancy with accuracy increasing to 99 percent by the third trimester, according to researchers.

Results of prospective evaluation were presented Thursday at the American Heart Association's 56^th Fall Conference and Scientific Sessions of the Council for High Blood Pressure Research.

Ramon C. Hermida, PhD, director of the bioengineering and chronobiology laboratories at the University of Vigo, Vigo, Spain, and colleagues used the investigational software program to analyze 2,430 blood pressure series sampled by ambulatory blood pressure monitoring (ABPM). "Blood pressure changes predictably during pregnancy. In healthy women blood pressure declines during the first half of pregnancy and then increases during the second half so that at delivery it is about the same as pre-pregnancy blood pressure," Dr. Hermida said in an interview. But, in women at risk for gestational hypertension or preeclampsia "there is no decrease in blood pressures during the first half of pregnancy and then there is a dramatic increase in the second half."

Moreover, women at risk for blood pressure-related complications "don't experience a nighttime decline or dip in blood pressure that is seen in healthy women."

ABPM was conducted for 48 hours every four weeks in 235 women with uncomplicated pregnancies and 168 women who developed gestational hypertension or preeclampsia. The monitoring began before the 14 week of pregnancy and continued until delivery.

The ABPM samplings were downloaded into a computer that analyzed the results using the "tolerance-hyperbaric test" software, which compares expected changes in a particular woman's blood pressure to a high blood pressure index (HBI). The index was developed using circadian 90 percent tolerance limits for BP to calculate HBI which are then computed as a function of trimester of gestation from a reference group of 189 normotensive pregnant women.

Sensitivity of the THT was 92.7 percent for women sampled during the first trimester of gestation, and increased up to 99.2 percent in the third trimester. Specificity was above 99 percent in all trimesters. The positive and negative predictive values were above 96 percent in all trimesters.

Dr. Hermida said the test can accurately predict both gestational hypertension and preeclampsia as early as "23 weeks before clinical symptoms." He said that his group will make the THT software available on the university website later this year.

E-Mail this DGDispatch to a colleague

To print, use this version