To ascertain whether atriomyoplasty, using the diaphragmatic muscle flap as the front wall of the atrio-pulmonary tunnel, results in successful Fontan repair.
Fontan operation, was performed on four adult mongrel dogs. Autological biological valves were created in the superior and inferior vena cava openings. The tendinous-muscle flap of the diaphragm, along with the diaphragmatic nerve, was inserted as the front wall of the atrio-pulmonary tunnel. The flap was either directly inserted into the circulatory system (2 cases) or applied externally onto the atrium wall (2 cases) and was stimulated through the diaphragmatic nerve with 7 burst impulses, at 6 volts each. Ventricular flap contraction was synchronized with contraction of the atrium.
Immediately after the operation, a sharp decrease was registered in cardiac output (2–2.5 L/min), arterial pressure (60–70 mmHg), pulmonary pressure (12–15 mmHg) and capillary saturation (SO2 <60–65. Central vein pressure increased (13–15 mmHg). Signs of right heart failure disappeared after beginning diaphragmatic flap stimulation. Before diaphragmatic flap stimulation began, pressure in the created neo chamber or right atrium was between 10/0–12/2 mmHg. Following initiation of flap stimulation, pressure in the neo chamber or right atrium was tracked for 3 hours and registered between 25/1–35/3 mmHg. Central vein pressure ranged from 6–7.6 mmHg and arterial pressure from 100/50–120/70 mmHg. The created autological valves functioned quite adequately with good locking function. Intraoperative echocardiogram measured blood flow through the caval veins at 8-12 mm/sec and the pulmonary artery at 70–80 mm/sec. The gradient in the created valves did not exceed 1–2 mmHg.
The stimulated, diaphragmatic flap plays the part of the actively contracting heart wall adequately without preliminary training. Autobiological valves, created in caval vein openings, perform the locking function properly, maintaining an adequate pressure level in the neo chamber or right atrium, comparable to the pressure in the right ventricle.
This new variant of the Fontan procedure could be used in the repair of several complex congenital cardiac defects.
Valeri Chekanov, University grant monies Tashkent Center of Surgery Grant