The pressure-controlled segmental carotid balloon injury. Is an experimental procedure used in the lab that mimics the balloon angioplasty revascularization procedure that is performed in human patients with severe atherosclerotic disease. It's used in the lab to study various aspects of the arterial injury response.
This re-stenosis model is performed in a similar manner to balloon angioplasty in the clinical setting allowing a defined area of vascular injury and complete re endothelialization within two weeks of injury to be achieved. After performing all of the preoperative procedures, according to the university IACUC standards, confirm a lack of response to pedal reflex in an anesthetized adult rat. Place the rat under a dissecting microscope and use scissors to make a straight 1.5 to two centimeter superficial longitudinal skin incision along the neck line between the jaw bones.
Make a second incision through the connective tissue under the skin until the muscle layer is exposed. And displace the salivary glands underneath the skin to access the muscle tissue. Insert closed scissor tips between the muscle layer and connective tissue and gently opened the scissors while pulling the skin upward to bluntly separate the connective tissue from the muscle.
Dissect the sternohyoid and sternomastoid muscles longitudinally along the left side of the trachea until the omohyoid muscle which runs perpendicular to the two superficial muscles is observed. Use forceps to gently create a window separating the perpendicular omohyoid muscle from the longitudinal sternohyoid muscle running over the trachea. And reach the forceps under the omohyoid muscle to separate the sternohyoid and sternomastoid muscles to expose the common carotid artery.
To isolate the common carotid artery, dissect the artery near the bifurcation until the internal and external carotid arteries are exposed. Using precut Proline sutures, ligate the superior thyroid and external carotid arteries near their respective bifurcations. Leaving the majority of the suture to one side of the nod and grabbing each suture with a curved hemostat.
Finish dissecting around the internal carotid artery and reach the forceps under and around the artery. Use a non crushing vascular clamp to carefully clamp around the occipital artery with the internal carotid artery to achieve distal control without kinking the vessels. Dissect the common carotid artery proximal to the bifurcation, taking care to separate the vagus nerve from the artery.
And reach forceps under and around the common carotid artery. Then use a non crushing vascular clamp to achieve proximal control, placing the clamp at least five millimeters from the bifurcation. To induce the balloon injury, maneuver the curved hemostats holding each litigated artery branch to expose the bifurcation between the external carotid artery and superior branch.
Gently dissect the tissue at the bifurcation to clear the arteriotomy site as much as possible. And use microdissection scissors to make an arteriotomy incision between the external carotid artery and the superior branch. Take care to clear the site prior to inserting the micro scissors and to ensure that one blade of the micro scissors is fully within the artery before making the incision.
Use a cotton swab to push all of the blood out of the common carotid artery and to clean up the arteriotomy site. Insert the uninflated balloon catheter through the arteriotomy by lifting the arteriotomy with forceps. And advance the balloon into the artery until the proximal end of the balloon is past the bifurcation.
If the balloon does not easily advance into the common carotid, reposition the angle of the balloon before trying again. Tape the catheter to the anesthesia nose cone so the balloon does not slip out of the artery during the inflation. And slowly fill the balloon to five atmospheres of pressure.
Leave the balloon in the artery for five minutes to induce the arterial injury before deflating and gently removing the balloon through the arteriotomy. Gently squeeze the clamp to flush out the artery. And ligate the external carotid artery proximal to the arteriotomy.
Remove the clamps from the common and internal carotid arteries to restore blood flow. And apply 50 microliters of therapeutic gel periadventiatially along the left and right sides of the injured artery. Then use interrupted 4-0 or 6-0 Vicryl sutures to close the connective tissue.
And close the skin with a running 4-0 nylon suture. Here, representative images of H and E stained arterial cross-sections of healthy, injured and treated arteries are shown. Using image J the perimeter of the neointima as well as the internal and external elastic lamina can be traced to quantify their respective areas.
Light sheet fluorescence microscopy can also be used to visualize the entire region of injury along the length of the artery. The images can then be rendered using software for quantifying the intima-media ratio. Be sure to place the internal carotid clamps so as not to kink the common carotid and to completely clear the arteriotomy site before inserting the microdissection scissors.
Many therapeutic approaches can be used at the end of surgery to attempt to mitigate the pathological response that is occurring within the carotid artery.
