After performing arterial cannulation in an anesthetized pig, using the cardiac ultrasound transducer, locate the position of the ascending aorta. Then mark the incision site and disinfect the chest of the animal. Using a scalpel, make a two to three centimeter skin incision at the level of the three-fourth intercostal space.
Then dissect the underlying fascia and muscle layers until the intercostal space is reached. Stop the ventilation without positive and expiratory pressure. Incise the intercostal muscles to enter the thorax.
Then increase the incision to allow the placement of the retractor blades. Retract the ribs and visualize the underlying structures. Using minimally invasive cardiac surgery forceps and scissors, open the pericardium.
Then use with sterile gauze to retract the left atria and any lung tissue covering the view of the aorta. Carefully separate the aorta from the pulmonary artery until the transverse pericardial sinus is reached. To facilitate aortic catheterization, place a radiopaque marker in the banding area.
Position the ePTFE graft or the nylon band around the ascending aorta. Connect a dual hemostasis valve adapter to a six French MP1 guide catheter, and flush it with heparinized saline. Preload the guide catheter with a 260-centimeter 0.035-inch J-tip guidewire and introduce this assembly through the femoral arterial sheath.
Under fluoroscopic guidance, advance the guide wire and guide the catheter into the ascending aorta. When the aortic valve is identified, carefully cross it with a guidewire and introduce the guide catheter into the left ventricle. Check pressure traces to confirm left ventricle positioning.
Next, remove the guidewire while leaving the guide catheter in the left ventricle. After aspirating the blood, flush the catheter with sterile saline and ensure no air bubbles are present in the catheter. After advancing two high-fidelity pressure sensors through the dual hemostasis valve adapter, pull the guide catheter back into the ascending aorta distally to the radiopaque marker placed on the banding site.
While leaving one of the high-fidelity pressure sensors in the left ventricle, confirm the catheter position using pressure traces. After left ventricle catheterization, close the nylon band one click at a time while closely monitoring pressures. Place sterile plastic tubing on the nylon band end to avoid accidental damage to the surrounding structures.
for ePTFE ends, constrict the band using 45-degree forceps. Monitor the pressure to estimate the relative location of the constriction. Finally, place a titanium hemoclip on the forceps position.
The use of high fidelity pressure sensors enables obtaining high quality pressure signals, allowing real time and accurate calibration of the stenosis. Transthoracic echocardiography confirm significant aortic stenosis immediately after surgery and during follow-up. Banding surgery resulted in significant aortic stenosis and left ventricular concentric hypertrophy.
Post-mortem macroscopic analysis of the heart revealed larger hearts and a thicker left ventricular wall.
