Comparison of flow-mediated dilation (FMD) of the brachial artery in normotensive versus preeclamptic pregnant females

Abstract

Introduction: Flow-mediated dilation (FMD) of the brachial artery is an ultrasonography test that assesses the endothelial response to reactive hyperemia. The aim of this study was to assess the changes in FMD in preeclamptic pregnant patients and compare them with normotensive pregnant females. Methods: An analytical cross-sectional comparative study was conducted in the Department of Obstetrics and Gynaecology at King George’s Medical University (KGMU) after obtaining ethical approval. A total of 110 normotensive and 100 preeclamptic patients were recruited for the study. Using a Toshiba Ultrasound Machine with a 7–12 MHz probe, the baseline diameter of the brachial artery D1 was measured. Afterward, the cuff of the sphygmomanometer was placed distally on the forearm and it was inflated up to ≥250 mm of Hg pressure and later slowly deflated. At 90th seconds after cuff deflation, the mean of three measurements of vessel caliber (D2) was obtained. The FMD% was obtained by the following equation: FMD (%) = [(D2 − D1)/D1] ×100, where D1 = basal diameter and D2 = post-occlusion diameter. All patients were followed till delivery for maternofetal outcome. Results: FMD% was significantly lower in the preeclampsia group, and it went on decreasing with increasing severity of preeclampsia. At the cutoff of 9.4 for FMD%, its sensitivity for the prediction of preeclampsia was 65.3%, specificity was 89.3%, positive predictive value (PPV) was 94%, and negative predictive value (NPV) was 50%. Discussion: FMD is a noninvasive test, and it gets decreased before clinical signs of preeclampsia, so it can be used as a predictor of preeclampsia.