Carson Jason, Warrander Lynne, Johnstone Edward, van Loon Raoul
Zienkiewicz Centre for Computational Engineering, College of Engineering, Swansea University, Swansea, UK.
Data Science Building, Swansea University Medical School, Swansea University, Swansea, UK.
Int J Numer Method Biomed Eng. 2021 Nov;37(11):e3267. doi: 10.1002/cnm.3267. Epub 2020 Jan 13.
Uterine artery Doppler waveforms are often studied to determine whether a patient is at risk of developing pathologies such as pre-eclampsia. Many uterine waveform indices have been developed, which attempt to relate characteristics of the waveform with the physiological adaptation of the maternal cardiovascular system, and are often suggested to be an indicator of increased placenta resistance and arterial stiffness. Doppler waveforms of four patients, two of whom developed pre-eclampsia, are compared with a comprehensive closed-loop model of pregnancy. The closed-loop model has been previously validated but has been extended to include an improved parameter estimation technique that utilises systolic and diastolic blood pressure, cardiac output, heart rate, and pulse wave velocity measurements to adapt model resistances, compliances, blood volume, and the mean vessel areas in the main systemic arteries. The shape of the model-predicted uterine artery velocity waveforms showed good agreement with the characteristics observed in the patient Doppler waveforms. The personalised models obtained now allow a prediction of the uterine pressure waveforms in addition to the uterine velocity. This allows for a more detailed mechanistic analysis of the waveforms, eg, wave intensity analysis, to study existing clinical indices. The findings indicate that to accurately estimate arterial stiffness, both pulse pressure and pulse wave velocities are required. In addition, the results predict that patients who developed pre-eclampsia later in pregnancy have larger vessel areas in the main systemic arteries compared with the two patients who had normal pregnancy outcomes.
子宫动脉多普勒波形常被用于研究患者是否有患先兆子痫等病症的风险。人们已经开发了许多子宫波形指标，这些指标试图将波形特征与母体心血管系统的生理适应性联系起来，并且常被认为是胎盘阻力增加和动脉僵硬度增加的一个指标。将四名患者（其中两名患先兆子痫）的多普勒波形与一个全面的妊娠闭环模型进行比较。该闭环模型此前已经过验证，但已进行扩展，纳入了一种改进的参数估计技术，该技术利用收缩压和舒张压、心输出量、心率以及脉搏波速度测量值来调整模型中的阻力、顺应性、血容量以及主要体循环动脉中的平均血管面积。模型预测的子宫动脉速度波形的形状与患者多普勒波形中观察到的特征显示出良好的一致性。现在获得的个性化模型除了能预测子宫速度外，还能预测子宫压力波形。这使得能够对波形进行更详细的机制分析，例如波强度分析，以研究现有的临床指标。研究结果表明，要准确估计动脉僵硬度，需要同时考虑脉压和脉搏波速度。此外，结果预测，与两名妊娠结局正常的患者相比，妊娠后期患先兆子痫的患者在主要体循环动脉中的血管面积更大。
