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Introduction: Although failing Fontan circulation has led to increased mortality and morbidity in long-term, little experimental model has been established to reconstitute Fontan circulation without any mechanical circulatory assistance in perioperative period in large animals. Hypothesis: We aimed to develop a novel Fontan failure model in pig by connecting inferior vena cava (IVC) with pulmonary artery (PA) and sought to investigate whether preconditioning by inferior vena cava (IVC) banding may improve the survival of IVC-PA connection model. Methods: IVC was connected to PA with14 mm ePTFE graft in 10 Yorkshire pigs (20-24 kg) via median sternotomy. One week before operation, IVC banding was performed as a preconditioning treatment (banding group). Five pigs (20-24 kg) were operated without IVC banding and assigned as control group. Results: Preconditioning by IVC banding showed increased IVC pressure (3.4±0.5 vs. 8.4±0.5 mmHg, P <0.01), decreased blood pressure (P <0.01), and increased heart rate (P =0.02). When pigs received IVC-PA connection , IVC pressure significantly increased after the operation in both groups (control group: 3.2±0.4 vs. 11.4±0.9 mmHg, P <0.01; banding group: 8.0±0.7 vs. 11.8±0.4 mmHg, P <0.01). However, IVC pressure changes were smaller in banding group than control group (control group: 8.2±0.8 vs. banding group: 3.8±0.4 mmHg, P <0.01). One hour after the operation, banding group showed higher systolic blood pressure than control group (control group: 50.8±6.6 vs. banding group: 72.0±7.1 mmHg, P <0.01). These small hemodynamic changes by pre-treatment of IVC banding improved survival after IVC-PA connection (Figure, control group: 0.6±0.1 vs. banding group: 6.2±0.8 days, log-rank P <0.01). Conclusions: Pre-treatment by IVC banding for 1 week may exert preconditioning effects to reduce the acute elevation of venous pressure after IVC-PA connection. This novel surgical strategy may be helpful to establish the Fontan circulation model in large animal to survive without mechanical support. [ABSTRACT FROM AUTHOR]

Introduction: Although failing Fontan circulation leads to increased mortality and morbidity in long-term, little experimental model has been developed to restitute the Fontan circulation without any circulatory support in large animals. Hypothesis: We investigated whether inferior vena cava (IVC) banding represents the abdominal complications in failed Fontan circulation with higher venous pressure and lower cardiac output. Methods: The IVC banding was performed in 5 Yorkshire piglets (20-23kg). The banding was adjusted as the mean IVC pressure increased to 5 mmHg. Sham operation was performed in another 5 piglets. Two months after the operation, models were assessed and sacrificed. Results: The mean IVC pressure increased (pre: 3.3±0.8 mmHg vs. post: 6.3±0.3 mmHg, P <0.01), and left ventricular end diastolic volume decreased (pre: 65.4±3.6 ml vs. post: 51.1±4.2 ml, P <0.01) in IVC banding models after the operation. Ascites was increased in IVC banding models, accompanied by decreased total protein, albumin, total cholesterol, and type 4 collagen in blood examination (all were P <0.01) in IVC banding group. Hepatic sinusoidal dilatation with diffuse fibrosis was observed in hematoxylin and eosin staining (Figure), and increased α-SMA and von Willebrand factor expression were detected by immunostaining. In tissue analysis, TNF-α expression increased in heart and liver, and α-SMA increased only in liver. In addition, type 3 collagen increased in liver and spleen that associated with increased expression of collagenase-related mRNA by RT-PCR. Matrix metalloproteinase 9 increased in spleen and intestine with decreasing in kidney, and CD45 remarkably expressed in spleen. Conclusions: IVC banding in piglet is novel surgical technique to reconstitute abdominal congestive complications. This reproducible procedure may be useful to develop the new therapeutic approaches for late congestive damages after Fontan operation. [ABSTRACT FROM AUTHOR]