Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD, USA.
Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA.
Ultrasound Obstet Gynecol. 2024 Sep;64(3):322-329. doi: 10.1002/uog.27636.
During human pregnancy, placental extravillous trophoblasts replace vascular smooth muscle and elastic tissue within the walls of the uterine spiral arteries, thereby remodeling them into distensible low-resistance vessels to promote placental perfusion. The present study determined whether B-flow/spatiotemporal image correlation (STIC) M-mode ultrasonography provides an in-vivo imaging method able to digitally quantify spiral artery luminal distensibility as a physiological index of spiral artery remodeling during the advancing stages of normal human pregnancy.
A prospective, longitudinal, observational study was conducted to quantify spiral artery distensibility (i.e. vessel luminal diameter at systole minus diameter at diastole) by B-flow/STIC M-mode ultrasonography during the first, second and third trimesters in 290 women exhibiting a normal pregnancy. Maternal serum levels of placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1), growth factors that modulate important events in spiral artery remodeling, were quantified in a subset of the women in the first, second and third trimesters of pregnancy.
Median (interquartile range (IQR)) spiral artery distensibility increased progressively between the first (0.17 (0.14-0.21) cm), second (0.23 (0.18-0.28) cm) and third (0.26 (0.21-0.35) cm) trimesters of pregnancy (P < 0.0001 for all). Median (IQR) spiral artery volume flow increased progressively between the first (2.49 (1.38-4.99) mL/cardiac cycle), second (3.86 (2.06-6.91) mL/cardiac cycle) and third (7.79 (3.83-14.98) mL/cardiac cycle) trimesters (P < 0.001 for all). In accordance with the elevation in spiral artery distensibility, the median (IQR) ratio of serum PlGF/sFlt-1 × 10 levels increased between the first (7.2 (4.5-10.0)), second (22.7 (18.6-42.2)) and third (56.2 (41.9-92.5)) trimesters (P < 0.001 for all).
The present study shows that B-flow/STIC M-mode ultrasonography provides an in-vivo imaging technology to quantify digitally the structural and physiological expansion of the walls of the spiral arteries during the cardiac cycle as a consequence of their transformation into compliant vessels during advancing stages of normal human pregnancy. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.
在人类妊娠期间，胎盘绒毛外滋养层细胞取代子宫螺旋动脉壁内的血管平滑肌和弹性组织，从而将其重塑为可扩张的低阻力血管，以促进胎盘灌注。本研究旨在确定 B 型血流/时空图像相关（STIC）M 型超声是否提供了一种能够数字化量化螺旋动脉管腔扩张度的体内成像方法，作为正常妊娠进展阶段螺旋动脉重塑的生理指标。
前瞻性、纵向、观察性研究，对 290 名正常妊娠妇女的第一、二、三孕期进行 B 型血流/STIC M 型超声测量螺旋动脉扩张度（收缩期血管腔直径减去舒张期直径）。在妊娠第一、二、三孕期的部分妇女中定量测定胎盘生长因子（PlGF）和可溶性 fms 样酪氨酸激酶-1（sFlt-1）的血清水平，这些生长因子调节螺旋动脉重塑的重要事件。
第一、二、三孕期螺旋动脉扩张度中位数（四分位距（IQR））逐渐增加（分别为 0.17（0.14-0.21）cm、0.23（0.18-0.28）cm 和 0.26（0.21-0.35）cm，P<0.0001）。第一、二、三孕期螺旋动脉容积流量中位数（IQR）逐渐增加（分别为 2.49（1.38-4.99）mL/心动周期、3.86（2.06-6.91）mL/心动周期和 7.79（3.83-14.98）mL/心动周期，P<0.001）。与螺旋动脉扩张度升高一致，血清 PlGF/sFlt-1×10 水平中位数（IQR）在第一、二、三孕期逐渐增加（分别为 7.2（4.5-10.0）、22.7（18.6-42.2）和 56.2（41.9-92.5），P<0.001）。
本研究表明，B 型血流/STIC M 型超声为一种体内成像技术，可数字化量化螺旋动脉壁在心动周期中的结构和生理扩张，这是由于它们在正常妊娠进展阶段转化为顺应性血管所致。© 2024 年国际妇产科超声学会。
