Greenberg S Bruce, Morrow W Robert, Imamura Michiaki, Drummond-Webb Jonathan
Arkansas Children's Hospital, Department of Pediatric Radiology, University of Arkansas for Medical Sciences, 800 Marshall Street, AR 72202 3591, Little Rock, USA.
Int J Cardiovasc Imaging. 2004 Oct;20(5):397-405; discussion 407-8. doi: 10.1023/b:caim.0000041941.59010.4c.
Energy inefficiencies lead to Fontan procedure failures. Our purpose was to quantify energy inefficiencies of various Fontan procedures using flow analysis.
The study included 12 patients with Fontan operations; 7 with classic trans-atrial flow and five extra-cardiac Fontans. Flow analysis was used to determine the systolic and diastolic flow in the superior vena cava and inferior venous circulations (IVC, right atrium or conduit). Retrograde flow fractions were calculated. Inferior venous flow analysis was obtained in 12 patients and superior vena cava in 9 patients.
A seesaw pattern (augmented inferior venous flow during diastole and augmented superior vena cava flow in systole) was present in five of seven patients with trans-atrial Fontan procedures, but no patient with an extra-cardiac Fontan procedure. Significant retrograde flow occurred in the superior vena cava in three children with trans-atrial Fontan procedures (retrograde flow fractions of 15-22%). Inferior venous flow occurred predominantly during diastole in five of seven children with trans-atrial Fontan procedures. Retrograde flow occurred in all seven children with the retrograde flow fractions ranging from 9 to 37% (mean 25%). Extracardiac Fontan flow was characterized by continuous balanced flow during systole and diastole. The association of the seesaw pattern with trans-atrial Fontan procedures was statistically significant (p = 0.028).
Classic trans-atrial Fontan procedures are characterized by energy inefficiency creating a seesaw flow pattern of forward and reverse flow. Extra-cardiac Fontan procedures are more energy efficient. Magnetic resonance imaging is useful in detecting flow inefficiencies in patients palliated by the Fontan procedure.
能量低效会导致Fontan手术失败。我们的目的是通过血流分析量化各种Fontan手术的能量低效情况。
该研究纳入了12例接受Fontan手术的患者；7例采用经典经心房血流方式，5例采用心外Fontan手术。采用血流分析来确定上腔静脉以及下腔静脉循环（下腔静脉、右心房或管道）中的收缩期和舒张期血流。计算逆向血流分数。对12例患者进行了下腔静脉血流分析，9例患者进行了上腔静脉血流分析。
7例接受经心房Fontan手术的患者中有5例出现了跷跷板模式（舒张期下腔静脉血流增加，收缩期上腔静脉血流增加），但接受心外Fontan手术的患者中无一例出现。3例接受经心房Fontan手术的儿童上腔静脉出现了显著的逆向血流（逆向血流分数为15% - 22%）。7例接受经心房Fontan手术的儿童中有5例下腔静脉血流主要发生在舒张期。所有7例儿童均出现逆向血流，逆向血流分数范围为9%至37%（平均25%）。心外Fontan血流的特点是收缩期和舒张期血流持续且平衡。跷跷板模式与经心房Fontan手术之间的关联具有统计学意义（p = 0.028）。
经典经心房Fontan手术的特点是能量低效，产生正向和反向血流的跷跷板血流模式。心外Fontan手术能量效率更高。磁共振成像有助于检测接受Fontan手术姑息治疗患者的血流低效情况。
