The Labatt Family Heart Centre and Department of Diagnostic Imaging, The Hospital for Sick Children, University of Toronto, Toronto, Canada.
Int J Cardiol. 2013 Sep 30;168(2):811-7. doi: 10.1016/j.ijcard.2012.10.008. Epub 2012 Nov 17.
The use of a fenestration in the Fontan pathway remains controversial, partly because its hemodynamic effects and clinical consequences are insufficiently understood. The objective of this study was to quantify the magnitude of fenestration flow and to characterize its hemodynamic consequences after an intermediate interval after surgery.
Twenty three patients with a fenestrated extracardiac conduit prospectively underwent investigation by cardiac magnetic resonance (CMR), echocardiography, and invasive manometry under the same general anesthetic 12 ± 4 months after Fontan surgery. Fenestration flow was determined using phase contrast CMR by subtracting flow in the Fontan pathway above the fenestration from Fontan flow below the fenestration.
Fenestration flow constituted a mean of 31 ± 12% (range 8-50%) of ventricular preload. It was associated with a lower Qp/Qs (r = -0.64, p=0.001) and oxygen saturation (r = -0.74, p<0.0001). Fenestration flow volume was correlated with pulmonary vascular resistance (r = 0.45, p = 0.04) and markers of ventricular diastolic function (early diastolic strain rate r = 0.57, p = 0.008 and ventricular untwist rate r = 0.54, p = 0.02). In 14 patients (61%) all of the net inferior vena cava flow and part of the superior vena cava flow were diverted into the systemic atrium and did not reach the lungs.
Fenestration flow can be measured accurately with CMR. In two-thirds of the patients not only all of the inferior vena cava flow, but also some of the superior vena cava flow is diverted through the fenestration. Fenestration flow is driven by a balance between pulmonary vascular resistance and early diastolic ventricular function.
在 Fontan 通路中使用开窗仍然存在争议，部分原因是其血流动力学效应和临床后果尚未充分了解。本研究的目的是量化开窗流量，并在手术后中期间隔时描述其血流动力学后果。
23 例接受体外腔静脉导管 fenestration 的患者，在 Fontan 手术后 12±4 个月，在同一全身麻醉下，前瞻性接受心脏磁共振（CMR）、超声心动图和有创压力测量。通过 CMR 相位对比测量 fenestration 流量，从 fenestration 下方的 Fontan 流量中减去 fenestration 上方的 Fontan 通路流量。
fenestration 流量构成心室前负荷的 31±12%（范围 8-50%）。它与较低的 Qp/Qs（r=-0.64，p=0.001）和氧饱和度（r=-0.74，p<0.0001）相关。fenestration 流量与肺血管阻力（r=0.45，p=0.04）和心室舒张功能标志物相关（早期舒张应变率 r=0.57，p=0.008 和心室解旋率 r=0.54，p=0.02）。在 14 例患者（61%）中，所有下腔静脉的净流量和部分上腔静脉的流量都通过 fenestration 转向体循环，而未到达肺部。
CMR 可准确测量 fenestration 流量。在三分之二的患者中，不仅所有的下腔静脉流量，而且部分上腔静脉流量都通过 fenestration 分流。fenestration 流量由肺血管阻力和早期舒张心室功能之间的平衡驱动。
