Romanowicz Jennifer, Park Sungho, Bunn Jenifer, Jacobsen Roni M, Fonseca Brian, Zablah Jenny E, Englund Erin K, Barker Alex J, Davidson Jesse A
Department of Pediatrics, Section of Cardiology, Children's Hospital Colorado and University of Colorado Anschutz, 13123 E 16th Ave, Aurora, Colorado 80045, USA.
Department of Radiology, Section of Pediatric Radiology, Children's Hospital Colorado, University of Colorado Anschutz, 13123 E 16th Ave, Aurora, Colorado 80045, USA.
J Cardiovasc Magn Reson. 2025 May 4;27(2):101907. doi: 10.1016/j.jocmr.2025.101907.
Accumulation of progressive extracardiac disease is nearly universal for patients with single ventricle heart disease palliated to a Fontan circulation; however, etiologies are poorly understood. Limited flow reserve in the Fontan circulation may underlie extracardiac disease found in Fontan physiology through reduced oxygen and nutrient delivery to the tissues. This study aimed to determine regional flow volumes and oxygen delivery to key organ systems in children and adolescents with a Fontan circulation.
In 17 Fontan subjects and 14 biventricular controls, regional arterial flow volumes to the carotid, celiac, superior mesenteric, renal, and iliac arteries were quantified with magnetic resonance imaging. Arterial oxygen content was calculated using subject hemoglobin level and pulse oximetry, and regional oxygen delivery was calculated using regional flow volume and oxygen content for the above-listed arteries. Cardiac output was measured from ascending aorta flow, systemic blood flow from the caval veins, and aorto-pulmonary collateral flow was calculated as the difference between the two. Flows were compared between groups (t-test) and associations were analyzed between flows and with maximal exercise performance on clinical cardiopulmonary exercise testing (Pearson correlation).
On average, renal and iliac arterial flows were lower in the Fontan group, compared to controls. Carotid, celiac, and superior mesenteric arterial flows were preserved in the Fontan group. Arterial oxygen content was equivalent between groups, and thus, regional oxygen delivery followed the same pattern as regional flows. Cardiac output was no different between groups, but systemic blood flow was lower in Fontans due to loss of flow to aorto-pulmonary collaterals. Systemic blood flow correlated with iliac flow such that those with the lowest systemic flow had the least amount of iliac flow. Celiac arterial flow correlated with percent-predicted peak oxygen consumption on exercise testing.
Our results are consistent with a limited flow reserve in the Fontan circulation with sacrifice of iliac arterial flow as global systemic blood flow decreases. Importantly, these data were measured with subjects supine and at rest. Future work requires the addition of exercise to determine how flow to specific organs is affected by increasing metabolic demand from the extremities.
对于接受Fontan循环姑息治疗的单心室心脏病患者，进行性心外疾病的累积几乎是普遍现象；然而，其病因尚不清楚。Fontan循环中有限的血流储备可能是Fontan生理学中的心外疾病的基础，因为向组织输送的氧气和营养物质减少。本研究旨在确定接受Fontan循环的儿童和青少年关键器官系统的局部血流量和氧气输送情况。
对17名Fontan受试者和14名双心室对照者，用磁共振成像对颈动脉、腹腔动脉、肠系膜上动脉、肾动脉和髂动脉的局部动脉血流量进行量化。利用受试者血红蛋白水平和脉搏血氧饱和度计算动脉血氧含量，并利用上述动脉的局部血流量和血氧含量计算局部氧气输送量。通过升主动脉血流量测量心输出量，通过腔静脉测量全身血流量，主动脉-肺侧支血流量计算为两者之差。对两组之间的血流量进行比较（t检验），并分析血流量与临床心肺运动试验中最大运动能力之间的相关性（Pearson相关性）。
平均而言，与对照组相比，Fontan组的肾动脉和髂动脉血流量较低。Fontan组的颈动脉、腹腔动脉和肠系膜上动脉血流量保持不变。两组之间的动脉血氧含量相当，因此，局部氧气输送与局部血流量遵循相同的模式。两组之间的心输出量没有差异，但由于主动脉-肺侧支血流的损失，Fontan组的全身血流量较低。全身血流量与髂动脉血流相关，全身血流最低者的髂动脉血流最少。腹腔动脉血流与运动试验中预测的峰值耗氧量百分比相关。
我们的结果与Fontan循环中血流储备有限一致，随着全身血流量的减少，髂动脉血流会减少。重要的是，这些数据是在受试者仰卧休息时测量的。未来的工作需要增加运动测试，以确定增加肢体代谢需求如何影响特定器官的血流。
