Understanding the regulatory control of complex blood flow in conduit arteries and veins

几十年来，心血管研究人员一直在研究大动脉和静脉直段的血液流动，发现血液流动模式如何影响我们血管的功能。然而，在现实中，我们的血管系统中很少有区域是由直管组成的，并且可以包含独特的特征，如分叉区域，其中一条血管分支成两条，或静脉瓣膜，以防止血液从心脏回流。虽然我们知道这些区域更有可能容纳“复杂”的血液流动特征（例如，分裂的血流，射流，再循环区），但我们对什么条件产生复杂的流动现象以及这些流动模式如何影响血管功能的理解很差。因此，这项研究计划的长期目标是更好地了解人体动脉和静脉中复杂血液流动的调节和影响。为了实现这一目标，将解决三个短期研究目标：1)开发用于估计人类复杂血流的生物医学超声技术；2)确定血管阻力、压力和壁刚度如何影响动脉分叉时复杂血流行为的大小；3)确定静脉瓣膜的存在如何影响大静脉的复杂血流。上述目标将通过结合先进的成像技术和非侵入性人体实验测试来实现，如肢体加热、呼吸动作、下半身吸力和单肢运动。该项目将采用先进的超声技术，可以可视化和量化复杂的血液流动，以研究动脉分支和静脉瓣膜，这是传统超声在临床单位中无法实现的。这项工作将通过提供人体模型数据来为血管疾病的复杂流体动力学模拟提供信息，建立人体模型来研究血流异常的病理生理学，并为不断发展的加拿大超声产业开发新的超声应用，从而使多个科学领域受益。参加该研究项目的学生将获得应用人体生理学和先进成像技术发展方面的宝贵经验，并参与灵活的培训环境，以支持学术和行业的职业发展道路。重点将放在应用编程技巧，以及针对人类心血管控制的特定方面的创造性研究设计上，例如血管压力、动脉硬度和血流。在明确的长期目标和以学生为中心的训练计划的激励下，该研究项目旨在发展血管生理学的一个新分支，产生关于如何在人体最难以接近和最复杂的血管区域控制血流的基础知识。

For decades, cardiovascular researchers have studied blood flow in straight segments of large arteries and veins, making discoveries in how blood flow patterns impact the function of our vessels. However, in reality, few regions of our vascular system are made of straight tubes, and can contain unique features such as bifurcation regions in which one vessel branches into two, or venous valves that act to prevent the backflow of blood away from the heart. While we know such regions are more likely to house `complex' blood flow features (e.g., splitting flow streams, flow jets, recirculation zones), we have a poor understanding of what conditions create complex flow phenomena and how these flow patterns impact vascular function. Accordingly, the long-term objective of this research program is to better understand the regulation and impact of complex blood flow throughout human arteries and veins. To achieve this goal, three short-term research objectives will be addressed: 1) to develop biomedical ultrasound techniques for the estimation of complex blood flow in humans; 2) to determine how vessel resistance, pressure, and wall stiffness contribute to the magnitude of complex blood flow behaviour in arterial bifurcations; and 3) to determine how the presence of venous valves impacts complex blood flow in the major veins. The above objectives will be met using a combination of advanced imaging techniques and non-invasive experimental tests in humans such as limb heating, breathing maneuvers, lower body suction, and single-limb exercise. This program will incorporate cutting-edge ultrasound techniques that allow the visualization and quantification of complex blood flow to study arterial bifurcations and venous valves, which is not achievable by conventional ultrasounds typically found in clinical units. This work will benefit multiple scientific domains by providing model human data to inform sophisticated fluid dynamics simulations of vascular disease, establishing human models to study the pathophysiology of blood flow abnormalities, and developing novel ultrasound applications for the growing Canadian ultrasound industry. Students who participate in this research program will gain valuable experience in both applied human physiology and development of advanced imaging technology, engaging in a flexible training environment to support both academic- and industry-track career paths. Emphasis will be placed on applied programming skills, and creative study design to target specific aspects of human cardiovascular control, such as vascular pressure, arterial stiffness, and blood flow. Motivated by a clear long-term objective and student-focused training plan, this research program seeks to develop a new branch of vascular physiology, generating foundational knowledge about how blood flow is controlled in the most inaccessible and complicated vascular regions of the human body.