Implantation of Left Ventricular Assist Device (LVAD) in Juvenile Landrace Swine: A LVAD Implantation Model of Pediatric Heart Failure

Our research establishes a juvenile pig model to study pediatric LVAD and heart reverse remodeling. A major challenge is the lack of a suitable animal model that represents a child's side and heart. To begin, make a three to four centimeter longitudinal incision at the junction of the upper and middle thirds of the line, connecting the mandibular angle to the manubrium sterni.

After the jugular vein, perform anterior vena cava puncture to monitor the central venous pressure. Establish femoral artery access for blood pressure measurement when necessary. Now, perform a median thoracotomy in the supine position.

Suspend the pericardium and fix it to expose the heart. Next, pass the LVAD signal line through the subcutaneous tunnel from the back and connect it to the controller to prevent the pig from rubbing against the signal line and causing it to fall off after waking up later. Then, determine the position and direction of the mitral valve with ultrasound.

Use a sterile surgical marker to draw the fixed position of the apical ring at the apex of the heart. Now, using a 5-0 suture thread with a gasket, fix the top ring at the apex position. Then, remove the myocardium within the parietal ring using an apical punch and trim with tweezers and scissors to prevent fragments from falling into the cardiac cavity.

Insert the LVAD pump head into the top ring, ensuring that the pump head enters the cardiac cavity. Fasten the lock tightly and remove the top ring clamp. Determine the appropriate length of the artificial blood vessel from the LVAD pump head to the ascending aorta.

Then, cut out an oblique opening at about a 30 degree angle and anastomose the end to the ascending aorta to avoid distortion of the artificial blood vessel. Now, place the ultrasound probe on the ascending aorta to examine the blood flow. Ensure that the blood flow through the artificial vessel is smooth and that there is no significant turbulence in the aorta.

Embed a drainage tube in each of the left and right spaces of the heart and connect an external negative pressure suction bottle. Finally, align the sternum and close the chest layer by layer. The left ventricular assist device implantation in a three-month old Landrace pig was successfully completed following the established protocol.

The preoperative electrocardiogram showed a normal cardiac rhythm before surgery. Postoperative electrocardiogram results on the 3rd and 14th days showed no abnormalities compared with the preoperative result. The preoperative echocardiography revealed a left ventricular ejection fraction of 62%and a fractional shortening of 26%The LVAD pump head was confirmed intraoperatively to face directly toward the mitral valve.

Postoperative echocardiography on the 14th day confirmed the LVAD pump head remained in place with normal ventricular wall motion and heart function. The left ventricle ejection fraction and fractional shortening remained within normal ranges throughout the 28-day postoperative period. Red blood cell count and hemoglobin decreased after surgery, but stabilized following transfusion.

Platelet count and neutrophil percentage fluctuated within the first three postoperative days likely due to surgical trauma. Liver and kidney function markers temporarily increased after surgery, but returned to normal within three days. The LVAD maintained stable function with an average rotational speed of 3, 600 revolutions per minute and flow around two liters per minute post-implantation.

Postoperative heart rate, systolic pressure, and diastolic pressure remained stable during continuous monitoring. We address the carotid gap for pediatrics model for safety and mechanical research. Our model use young mimic the heart size and of children.

This model will help us develop safer, more effective ventricular assist devices for children.