Objectives: To assess flow-mediated dilatation (FMD) in women with preeclampsia (PE) versus gestational hypertension (GH) and to determine if results of this ultrasound method vary with modifications to the technique.
Methods: Pregnant women with hypertension (BP ≥ 140/90 mmHg) were recruited. Women were allocated to the PE group if they had proteinuria ≥300 mg/24 h. FMD(o) was calculated from the percentage difference in baseline and post-occlusion (PO) diameter at 45-60 s and FMD(max) from baseline and maximum diameter between 45 and 90 s. FMD(max) was adjusted for hematocrit and shear rate.
Results: FMD(o) (m ± SD) was similar (p = 0.83) in the no medication GH (5.3 ± 3.2; n = 15) and the PE (6.5 ± 4.1; n = 13) groups. FMD(o) was reduced (p < 0.001) in the medication GH (3.7 ± 2.8; n = 23) versus the PE (8.8 ± 4.3; n = 25) groups. For FMD(max) the interaction between group and medication was not significant (both p = 0.08) in unadjusted analysis or analysis adjusted for covariates hematocrit (p = 0.023) and shear rate (p = 0.007). Means averaged over medication are presented. FMD(max) was reduced (p < 0.0001) in the GH (5.7 ± 4.0; n = 38) versus the PE group (9.2 ± 4.0; n = 38). Of the PE women, 79% (30/38) reached maximum dilatation by 90 s compared with 63% (24/38) of the GH women (chi-square, p = 0.16).
Conclusions: The FMD(max) analysis revealed reduced FMD in GH women compared with PE women. We therefore hypothesize that PE may be a different disease to GH. Our work demonstrates differing results in FMD(o) and FMD(max) because of modifications in the technique. Previous work on PE and FMD may not be definitive due to this evolving technique.