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室(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，在这种手术中，心脏的右侧被搭桥，血液直接进入肺部，而不需要泵室。这种手术是分阶段进行的。在最初的手术中，建立了从主动脉到肺动脉的连接，并重建了从心脏流出的流量(阶段I)。在中期，来自上腔静脉的血流直接进入肺动脉，而下腔静脉的血流则直接进入单个脑室。Fontan完成手术包括通过挡板或管道将下腔静脉血液输送到肺动脉。众所周知，单心室患者的神经系统问题也比普通人群和其他形式的冠心病更严重。其中一个因素是脑血流(CBF)；来自我们实验室的初步数据以及发表的文献中的证据表明，CBF的量与智力有关。有理由相信单脑室患者的CBF不同于正常儿童，并且在手术重建过程中会发生变化。在第一阶段，主动脉和肺动脉之间的连接会降低血压，并将血液吸入肺部。在第二个阶段，大脑和肺直接串联在一起，而且只相互连接(血液从主动脉流向大脑，然后直接进入上腔静脉通往肺部)。最后，完成Fontan重建后，脑静脉压升高。这些阶段的脑血流量仍然未知，随着二氧化碳增加导致脑血流量的变化，这增加了大脑的流量，是大脑适应能力以满足其血液需求的一个标志。事实上，文献中没有关于正常儿童脑血流量的数据。这一点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。阐明单个脑室的CBF可能最终导致这些患者的管理发生变化；例如，如果某个阶段对CBF有不利影响且不正常，则可能谨慎地提前完成Fontan，而不是典型的18个月时间框架。通过我们实验室以前所做的准确测量CBF，磁共振成像(MRI)提供了一个独特的机会来非侵入性地测量CBF、CBF对二氧化碳的反应以及脑体积和异常。了解与正常儿童相比，单脑室的CBF如何随着手术阶段的变化而变化，可能有助于理解他们为什么会有神经问题，并可能改变内科或外科治疗。这是一项前瞻性、非随机、单中心的研究，建立在单脑室患者和其他形式的CHD患者通过MRI的CBF初步数据的基础上，旨在确定在分期手术重建过程中，与正常儿童相比，单脑室的CBF变化。项目简介：在美国，出生时心脏只有一个可用的泵室(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，并遭受神经问题的困扰。通过了解流向大脑的血液是如何与正常人不同的，以及在这些患者的手术过程中血液是如何变化的，我们或许能够更好地了解他们为什么会出现神经问题，以及可以采取什么措施进行干预。通过手术改变这些患者的血液流动方式可能会改变我们最终在医学和手术方面管理这些患者的方式。

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.