Fogel M A, Weinberg P M, Hoydu A, Hubbard A, Rychik J, Jacobs M, Fellows K E, Haselgrove J
Department of Pediatrics, Children's Hospital of Philadelphia, Pa., USA.
J Thorac Cardiovasc Surg. 1997 Dec;114(6):1032-41. doi: 10.1016/S0022-5223(97)70017-5.
Our objectives were twofold: (1) to determine cardiac and respiratory dependency of systemic venous pathway flow of patients having the Fontan operation with a total cavopulmonary connection and (2) to describe the velocity profile. Systemic venous pathway flow is hypothesized to be mostly respiratory dependent, to be laminar, and to have a smooth velocity profile.
Twenty-two patients having the Fontan operation (aged 8.6 +/- 4.7 years) underwent magnetic resonance blood tagging (bolus tagging). Systemic venous pathway spin-echo images parallel to the blood flow were used as a localizer. A saturation pulse labeled the blood, and a cine image was acquired at the inferior and superior venae cavae and midportion of the baffle in the systemic venous pathway, triggered to the electrocardiogram and gated to both end-expiration and end-inspiration. Repetition time was 50 msec.
Flow in the systemic venous pathway was laminar throughout its course and was found to be phasic to both cardiac and respiratory cycles. Approximately 70% of flow was cardiac dependent, and the rest was respiratory. Highest flow occurred near end-systole and early diastole and in inspiration. Lowest flow occurred in diastasis. Velocity was highest and flow least "pluglike" in the mid-baffle area during cardiac or respiratory imaging (45 +/- 17 and 32 +/- 11 cm/sec, respectively).
A substantial amount of pulmonary blood flow in patients who have undergone a total cavopulmonary connection type of Fontan operation has a cardiac component. Furthermore, we confirm that this flow is laminar but nonuniform across the systemic venous pathway. Highest flows occurred near end-systole and early diastole, as well as in inspiration, and the lowest flow occurred in diastasis. This information may help in designing the systemic venous pathway and optimizing medical management.
我们的目的有两个：（1）确定接受全腔静脉肺动脉连接的Fontan手术患者体静脉通路血流的心脏和呼吸依赖性；（2）描述速度剖面。假设体静脉通路血流主要依赖呼吸，呈层流状态，且速度剖面平滑。
22例接受Fontan手术的患者（年龄8.6±4.7岁）接受了磁共振血液标记（团注标记）。与血流平行的体静脉通路自旋回波图像用作定位图。一个饱和脉冲标记血液，并在体静脉通路的下腔静脉、上腔静脉和挡板中部采集电影图像，触发至心电图，并在呼气末和吸气末进行门控。重复时间为50毫秒。
体静脉通路中的血流在整个过程中呈层流状态，并且发现与心脏和呼吸周期均呈阶段性变化。大约70%的血流依赖心脏，其余依赖呼吸。最高血流出现在收缩末期和舒张早期以及吸气时。最低血流出现在舒张中期。在心脏或呼吸成像期间，挡板中部的速度最高，血流最不像“塞子状”（分别为45±17和32±11厘米/秒）。
接受全腔静脉肺动脉连接型Fontan手术的患者，其大量肺血流具有心脏成分。此外，我们证实这种血流是层流，但在体静脉通路中不均匀。最高血流出现在收缩末期和舒张早期以及吸气时，最低血流出现在舒张中期。这些信息可能有助于设计体静脉通路并优化医疗管理。
