OBJECTIVE: A device for pulmonary trunk (PT) banding with percutaneous adjustment was developed with the aim of inducing rapid hypertrophy of the subpulmonary ventricle. MATERIAL AND METHODS: It consists of a silicon cuff occluder which holds the pulmonary trunk; an extension tube that connects the cuff to an auto-sealing silicon button, in which water is injected percutaneously to inflate the cuff and adjust the systolic load to the subpulmonary ventricle. The hearts of seven young goats (average wt.: 8.7 kg) were submitted to systolic overload imposed by the device and assessed under hemodynamic, echocardiographic and morphologic aspects. Baseline myocardial samples of the right ventricular outflow tract were harvested for microscopic analysis (perimeter and area of the myocyte). The device was then placed on the PT. The pressures in the right ventricle (RV), PT and aorta were monitored. After convalescence, the protocol of insufflation of the banding device was initiated in order to achieve a RV systolic pressure 70% of the left ventricle systolic pressure. The hemodynamic and echocardiographic evaluations were performed every 24 hours. The RV systolic overload was maintained through a 96 hours period, with gradual insufflations of the cuff every 24 hours, according to the tolerance of the animal to the pressure load. After this period, the animals were killed for morphologic evaluation of the heart. Another nine goats (average wt.: 7.7 kg) were used as control group to compare the ventricle muscle weight. RESULTS: After 96 hours of RV systolic overload, it was observed an increase in systolic gradient RV/PT, from 10.1±4.3 mmHg to 60,0±11,0 mmHg and in the RV systolic pressure, from 22.4±4.1 mmHg to 71.0±10.0 mmHg (p<0.0001). Serial echocardiography showed an increase of the RV thickness, from 4.4±0.5 mm to 7.3±1.7 mm (p=0.001). Regarding RV weight, there was a 74% increase in the RV submitted to the systolic overload, when compared to the control group (p<0.0001). Under optic microscopy, a 27% increase in perimeter and 69% increase in area of the myocytes were observed (p=0.0001). CONCLUSIONS: The device considered in this work is effective and easily adjustable percutaneously, suggesting that the prepare of the subpulmonary ventricle could probably be accomplished in a 96 hour period of systolic overload. Improvements in the adjustment of the PT banding may allow better results of the two-stage Jatene operation in patients with transposition of the great arteries.
Heart ventricle; Heart ventricle; Heart ventricle; Cardiac surgical procedures; Transposition of great arteries; Pulmonary trunk banding device; Pulmonary artery; Reconstructive surgical procedures
