Cerebral Blood Flow in Single Ventricle and Normal Children Utilizing MRI

描述（由申请人提供）：在美国，出生时心脏只有一个可用的泵腔（单心室）的儿童是先天性心脏病（CHD）发病率和死亡率的主要原因。最常见的修复方法是改良的Fontan手术，即绕过心脏右侧，将血液直接输送到肺部，而不需要泵送室。手术分阶段进行。在最初的手术中，从主动脉到肺动脉的连接被建立，心脏的流出被重建（阶段一）。在中间阶段，来自上腔静脉的血流直接进入肺动脉，而下腔静脉的血流直接进入单心室。Fontan完成包括将下腔静脉血液通过挡板或导管输送到肺动脉。与普通人群和其他形式的冠心病相比，单心室患者也有更大的神经问题。其中一个影响因素是脑血流量（CBF）；从我们实验室的初步数据以及发表的文献中得到的证据表明，脑卒中的数量与智力有关。有理由相信单脑室患者的脑血流与正常儿童不同，并在分阶段手术重建过程中发生变化。在第一阶段，主动脉和肺动脉之间的连接降低血压并将血液吸入肺部。在第二阶段，大脑和肺部直接串联在一起，并且只相互连接（血液从主动脉流向大脑，然后直接流入上腔静脉，最后到达肺部）。最后，在Fontan重建完成后，脑静脉压升高。这些阶段的脑血流量以及脑血流随二氧化碳增加的变化仍然未知，二氧化碳增加了脑血流，这是大脑适应满足其血流需求的程度的标志。事实上，在文献中没有关于正常儿童CBF的数据。这在这个年龄尤其重要，因为大脑发育的这个快速增长阶段可能与最终的神经功能有关。阐明单心室CBF可能最终导致这些患者管理的改变；例如，如果某一阶段对CBF有不利影响，并且不正常，则可能更早完成Fontan，而不是通常的18个月时间框架。通过准确测量CBF，磁共振成像（MRI）提供了一个独特的机会，可以无创地测量CBF， CBF对二氧化碳的反应以及脑容量和异常情况。与正常儿童相比，了解单心室CBF随手术阶段的变化可能有助于理解为什么他们有神经问题，并可能改变医疗或手术管理。这是一项前瞻性、非随机、单中心研究，建立在单心室患者和其他形式冠心病患者通过MRI获得的CBF初步数据的基础上，旨在确定与正常儿童相比，分阶段手术重建期间单心室CBF的变化。项目说明：在美国，出生时心脏只有一个可用的泵腔（单心室病变）的儿童是先天性心脏病发病率和死亡率的主要原因，并患有神经系统问题。通过了解流向大脑的血液与正常人的不同之处，以及这些患者在手术过程中的变化，我们可能更好地理解他们为什么会有神经系统问题，以及可以采取什么措施进行干预。通过手术改变这些病人的血液流动方式可能会改变我们最终对这些病人进行医学和外科治疗的方式。

DESCRIPTION (provided by applicant): Children who are born with a heart containing only one usable pumping chamber (single ventricle) are the leading cause of morbidity and mortality from congenital heart disease (CHD) in the United States. The most common repair is the modified Fontan operation in which the right side of the heart is bypassed and blood is channeled directly to the lungs without a pumping chamber. This surgery is performed in stages. In the initial operation, a connection is created from the aorta to the pulmonary arteries and the outflow from the heart is reconstructed (Stage I). In an intermediate stage, flow from the superior vena cava is channeled directly into the pulmonary arteries while the inferior vena caval flow enters the single ventricle directly. The Fontan completion involves routing inferior vena caval blood to the pulmonary arteries via a baffle or conduit. Patients with single ventricle are also known to have greater neurological problems than the general population and other forms of CHD. One contributing factor is cerebral blood flow (CBF); evidence from preliminary data from our lab as well as in the published literature suggests that the amount of CBF is related to intelligence. There are reasons to believe that CBF in single ventricle patients is different from normal children and changes throughout staged surgical reconstruction. At Stage I, the connection created between the aorta and pulmonary arteries decrease blood pressure and suck blood into the lungs. In the second stage, the brain and lungs are hooked up directly in series with each other and only with each other (blood flows from the aorta to the brain and then directly into the superior vena cava to the lungs). Finally, after complete Fontan reconstruction, brain venous pressures are elevated. The amount of CBF during these stages remain unknown along with the change in CBF with increased carbon dioxide which increases brain flow and is a marker for how well the brain can adapt to meet its blood flow needs. Indeed, there is no data on CBF in normal children in the literature. This is especially important at this age since this rapid growth stage of brain development may be related to ultimate neurological function. Elucidating CBF in single ventricles may ultimately lead to changes in management of these patients; if one stage has an adverse effect on CBF for example and is not normal, it might be prudent to complete the Fontan earlier rather than the typical 18 month timeframe. By accurately measuring CBF which our lab has done previously, magnetic resonance imaging (MRI) offers a unique opportunity to measure CBF non-invasively, CBF response to carbon dioxide as well as brain volumes and abnormalities. Understanding how CBF changes in single ventricles with the stage of surgery as compared to normal children may lead to understanding why they have neurological problems and possibly change medical or surgical management. This is a prospective, non-randomized, single center study built upon preliminary data on CBF in single ventricle patients and other forms of CHD via MRI and seeks to determine CBF changes in single ventricles during staged surgical reconstruction as compared with normal children. Project Narrative: Children who are born with a heart containing only one usable pumping chamber (single ventricle lesion) are the leading cause of morbidity and mortality from congenital heart disease in the United States and suffer from neurological problems. By understanding how blood flow to the brain is different from normals and how it changes during surgery in these patients, we may better be able to understand why they have neurological problems and what can be done to intervene. Changing the way the blood flows in these patients by surgery may alter the way we ultimately manage these patients medically and surgically.