Magnetic Resonance Imaging Assessment of Blood Flow Distribution in Fenestrated and Completed Fontan Circulation with Special Emphasis on Abdominal Blood Flow

OBJECTIVE: To investigate the regional flow distribution in patients with Fontan circulation by using magnetic resonance imaging (MRI). MATERIALS AND METHODS: We identified 39 children (18 females and 21 males; mean age, 9.3 years; age range, 3.3–17.0 years) with Fontan circulation in whom flow volumes across the thoracic and abdominal arteries and veins were measured by using MRI. The patients were divided into three groups: fenestrated Fontan circulation group with MRI performed under general anesthesia (GA) (Group 1, 15 patients; average age, 5.9 years), completed Fontan circulation group with MRI performed under GA (Group 2, 6 patients; average age, 8.7 years), and completed Fontan circulation group with MRI performed without GA (Group 3, 18 patients; average age, 12.5 years). The patient data were compared with the reference ranges in healthy controls. RESULTS: In comparison with the controls, Group 1 showed normal cardiac output (3.92 ± 0.40 vs. 3.72 ± 0.69 L/min/m2, p = 0.30), while Group 3 showed decreased cardiac output (3.24 ± 0.71 vs. 3.96 ± 0.64 L/min/m2, p = 0.003). Groups 1 and 3 showed reduced abdominal flow (1.21 ± 0.28 vs. 2.37 ± 0.45 L/min/m2, p < 0.001 and 1.89 ± 0.39 vs. 2.64 ± 0.38 L/min/m2, p < 0.001, respectively), which was mainly due to the diversion of the cardiac output to the aortopulmonary collaterals in Group 1 and the reduced cardiac output in Group 3. Superior mesenteric and portal venous flows were more severely reduced in Group 3 than in Group 1 (ratios between the flow volumes of the patients and healthy controls was 0.26 and 0.37 in Group 3 and 0.63 and 0.53 in Group 1, respectively). Hepatic arterial flow was decreased in Group 1 (0.11 ± 0.22 vs. 0.34 ± 0.38 L/min/m2, p = 0.04) and markedly increased in Group 3 (0.38 ± 0.22 vs. −0.08 ± 0.29 L/min/m2, p < 0.0001). Group 2 showed a mixture of the patterns seen in Groups 1 and 3. CONCLUSION: Fontan circulation is associated with reduced abdominal flow, which can be attributed to reduced cardiac output and portal venous return in completed Fontan circulation, and diversion of the cardiac output to the aortopulmonary collaterals in fenestrated Fontan circulation.

Transcatheter closure of secundum atrial septal defects and fenestrated Fontan using the Amplatzer septal occluder: Initial prospective study / Cierre transcateterismo de defectos septales atriales y Fontan fenestrado mediante el dispositivo de Amplatzer: Estudio prospectivo inicial

Objective: To evaluate the safety and efficacy of transcatheter closure of secundum atrial septal defects and fenestrated Fontan with the Amplatzer septal occluder. Methods: Fifteen consecutive patients, with a significant interatrial communications, were considered for the procedure; four patients with defects that were too large or with deficient margins were excluded after initial transesophageal echocardiography. Results: Eleven procedures were performed in 11 patients (10 atrial septal defects and 1 fenestrated Fontan) aged 9 to 38 years, mean 17.7 ± 9 years; body weight 30 to 87 kg, mean 51.4 ± 16. The stretched balloon diameter of the defects ranged from 8 to 28 mm, mean 18.8 ± 6.9; the diameter of the devices ranged from 10 to 30 mm, mean 20.8 ± 6. Immediate total occlusion rate was 18.1%, rising to 63.6% after 24 hours. Total occlusion rate at one month reached 100%. Severe transient sinus bradycardia in one (9%) was the only complications. At follow-up (10 to 26 months, mean 13.2 ± 5.0) all patients remain asymptomatic with no residual shunt. Conclusions: The Amplatzer septal occluder is very efficient and offered interventional interatrial communications closure in 100% of our group of consecutive patients with excellent intermediate results.

Objetivo: Evaluar la seguridad y eficacia del cierre transcateterismo de defectos septales atriales y Fontan fenestrado mediante el dispositivo de Amplatzer. Método: Quince enfermos consecutivos con comunicaciones interauriculares significativas fueron considerados inicialmente; se excluyeron 4 de ellos por defectos demasiado grandes o con bordes deficientes después de ecocardiografía transesofágica inicial. Resultados: Se realizaron 11 procedimientos en 11 enfermos (10 con defectos septales auriculares y uno con Fontan fenestrado), el rango de edad fue de 9 a 38 años, media 17.9 ± 9 años; peso de 30 a 87 kg, media 51.4 ± 16. El diámetro de balón ajustado al defecto varió de 8 a 28 mm, media 18.8 ± 6.9; el diámetro de los dispositivos varió de 10 a 30 mm, media 20.8 ± 6. La oclusión total inmediata ocurrió en el 18.1%, subiendo a 63.6% a las 24 horas. La oclusión total en el 100% de los enfermos se obtuvo al mes de seguimiento. Complicaciones: Se produjo severa bradicardia sinusal transitoria en un enfermo (9%). El seguimiento varió de 10 a 26 meses, media 13.2 ± 5.0. Todos los enfermos se encuentran asintomáticos sin corto circuito residual. Conclusiones: El oclu-sor Amplatzer es muy eficiente y ofrece el cierre de las comunicaciones interauriculares en el 100% de nuestro grupo de enfermos consecutivos con excelentes resultados a mediano plazo. (Arch Cardiol Mex 2003; 73:185-189).