618: Is endothelia function impaired among women with twin gestations? Evidence from a prospective cohort study using peripheral artery tonometry

Abstract

Reactive hyperemia-peripheral artery tonometry (RH-PAT, EndoPAT) has been developed as a simple method to determine endothelial function. Our aim was to determine whether endothelial function is impaired in women with twin gestations compared to singletons using EndoPAT. A prospective cohort study of 41 pregnant women who underwent endothelial function assessment using EndoPAT device between 25 and 35 weeks of gestation. Women with twin pregnancies (study group, n=19) were matched by gestational age at testing to women with singleton pregnancies (control group, n=22). Exclusion criteria included chronic hypertension, preeclampsia, gestational hypertension, diabetes mellitus, renal disease and smoking. EndoPAT evaluates the change in peripheral vascular tone in reaction to temporal ischemia in a process called reactive hyperemia. The ratio of the readings before and after ischemia is used to calculate the score for endothelial function and called reactive hyperemia index (RHI). Abnormal RHI indicating endothelial dysfunction is defined as RHI ≤ 1.67 in the non-pregnant population. All exams were undertaken between 6:00-8:00am following a 6 hour fast by two operators. Maternal age, parity, body mass index, systolic and diastolic blood pressure and gestational age at the time of testing did not differ between the two groups. Mean RHI did not differ significantly between women with twins compared to singletons (1.59±0.4 vs 1.58±0.3 respectively, p=0.45). Interestingly, most women in both twins and singleton groups exhibited an RHI of ≤1.67 indicating peripheral endothelial dysfunction (78% vs 76% respectively, p=0.5). A sub-group analysis showed no difference in RHI between women with discordant twins and women with non-discordant twins (1.64±0.56 vs 1.57±0.34 respectively, p=0.35). Peripheral endothelial function measured with EndoaPAT is similar between women with twins gestations compared to singletons. Importantly, the majority of pregnant women with either twins or singleton gestation exhibit endothelial dysfunction during pregnancy.