Placental Growth Factor Predicts Preeclampsia Risk
For women presenting before 35 weeks’ gestation with suspected preeclampsia, low levels of placental growth factor (PlGF) have high sensitivity and negative predictive value (NPV) for identifying women who will need to deliver within 14 days because of the disease, according to a study published online Nov. 4 in Circulation. P1GF has better test characteristics […]
For women presenting before 35 weeks’ gestation with suspected preeclampsia, low levels of placental growth factor (PlGF) have high sensitivity and negative predictive value (NPV) for identifying women who will need to deliver within 14 days because of the disease, according to a study published online Nov. 4 in Circulation. P1GF has better test characteristics than other currently used tests and can improve disease monitoring, preventing unnecessary care. The test, made by Alere (Waltham, Mass.), still needs U.S. regulatory approval for clinical use. Current diagnosis relies on blood pressure and proteinuria, which experts say are of limited use because they are tertiary features of the disease reflecting end-organ disease and are poorly predictive of subsequent adverse outcomes. P1GF increases in concentration in maternal circulation (peaking at 26 weeks’ to 30 weeks’ gestation) but can serve as a secondary marker of associated placental dysfunction in preeclampsia, with low concentrations associated with the disease. Researchers conducted a prospective, multicenter trial (from January 2011 to February 2012) in which the diagnostic accuracy of low plasma PlGF concentration (less than the fifth centile for gestation) was evaluated using the Alere Triage assay in 625 women presenting with suspected preeclampsia between 20 weeks’ and 41 weeks’ gestation. The study found that 55 percent of women developed confirmed preeclampsia. When limiting evaluation to the 287 women enrolled before 35 weeks’ gestation, PlGF levels less than the fifth centile (or ≤100 pg/mL) had 96 percent sensitivity and a 98 percent NPV for preeclampsia within 14 days. Specificity was lower (0.55). Low PlGF was significantly better at predicting preeclampsia than all other commonly used tests, singly or in combination. “We hypothesize that adding PlGF measurement to current clinical assessment of women with suspected preeclampsia before 37 (and particularly before 35) weeks’ gestation could improve risk stratification, achieve an earlier diagnosis based on underlying pathophysiology, enable individualized management of women with the disease, with the potential to reduce associated maternal morbidity and unnecessary health service usage,” write the authors, led by Lucy C. Chappell, Ph.D., King’s College London (United Kingdom). Paul Sheard, a spokesperson for Alere, tells DTET that the Triage PIGF assay, which launched in Europe in 2011, will likely not be released in the United States before 2015 as the company must complete the premarket approval process with the U.S. Food and Drug Administration (FDA). To date the company has completed the necessary clinical trials and has had preliminary discussions with the FDA. Several authors report financial ties to Alere, which partially funded the study. Takeaway: PlGF has potential to improve the diagnosis of preeclampsia and impact both outcomes and usage of health care services.