The overall goal of this protocol is to perform a minimally invasive aortic valve replacement through a right anterior mini-thoracotomy with central aortic cannulation. This method can help answer key questions regarding minimally invasive approaches for other heart valves, including the mitral and the tricuspid valves. The main advantage of this technique is that it combines a central aortic cannulation with the preservation of rib integrity.
After marking the incision site, use an 18 blade knife to make an eight centimeter transverse incision one centimeter to the right of the sternal edge over the intercostal space of interest, followed by electrocauterization of the pectoralis and the superficial layers of the intercostal muscles. Enlarge the intercostal muscle opening with electrocautery. Then, enter the right pleura with Metzenbaum scissors to avoid injury to the right lung and free the right internal thoracic pedicle from the fascia and soft tissue.
Insert a soft tissue retractor into the right pleura and secure the retractor in place. Place a minimal access retractor over the soft tissue retractor, and gently open the minimal access retractor. Gently push down the right lung with a gauze to expose the pericardium and cut the fat with electrocautery.
Open the pericardium cranially over the ascending aorta and caudally over the right atria. After locating the right superior pulmonary vein, to expose the distal end of the ascending aorta, use a peanut gauze to gently push down the ascending aorta. Use a 4-0 polypropylene suture to place the first purse-string for aortic cannulation just below the distal pericardial reflection line over the ascending aorta.
Use another 4-0 polypropylene suture to add a second purse-string around the first suture to complete the aortic cannulation preparation. After delivering 300 IU of heparin per kilogram through the IV line, puncture the right femoral vein and place the guide wire through the needle into the vein. Enlarge the skin opening with an 11 blade knife and dilate the puncture site with successive dilators.
Introduce the femoral venous cannula percutaneously over the guide wire. Then, puncture the ascending aorta in the middle of the purse-strings and cannulate the aorta over the guide wire. Next, gently push the superior vena cava toward the left side, and use a 4-0 polypropylene monofilament suture to place a purse-string on the right upper pulmonary vein.
Insert the left ventricular vent through the purse-string to unload the left heart. Extend the aortotomy through the non-coronary sinus to one centimeter above the aortic annulus and check the left and right coronary ostia. Using endo forceps, grasp the left coronary cusp and use endo scissors to excise the left coronary cusp.
Check the mitral valve through the aortotomy and use commercially available valve sizers to identify a valve that comfortably passes through the aortoventricular junction. Use an endo needle holder to place the first braided polyester 2-0 with a pledget U-suture onto the commissure between the left and right coronary sinuses, and pass the suture from the ventricle upward so that the pledget is on the ventricle side, continuing the placement of the braided polyester 2-0 with pledget U-sutures clockwise to complete the right coronary sinus. Place clockwise braided polyester 2-0 with pledget U-sutures on the non-coronary sinus and place a counterclockwise braided polyester 2-0 with pledget U-sutures on the left coronary sinus to complete the annulus sutures, using a Ryder needle holder to pass the braided polyester 2-0 sutures onto the sewing ring of the valve prosthesis.
Slide down the valve prosthesis and remove the valve holder. Tie the sutures and check for any gaps between the sutures and the aortic annulus, verifying that the left and right coronary ostia are unobstructed. Use Metzenbaum scissors to cut the tied sutures ends and remove the 5-0 exposure sutures on the inferior and superior ridge of the aortotomy.
Place one 5-0 polypropylene running hemi-suture starting on the nadir of the aortotomy in the non-coronary sinus to the middle of the aortotomy. Place a second 5-0 polypropylene running hemi-suture starting on the left end of the aortotomy, and continue toward the right end of the incision to meet the end of the first hemi-suture. After tying both suture ends together, gently aspirate the left ventricular vent.
Place the ventricular pacing wires on the right ventricle before unclamping the aorta. Remove the aortic cross clamp and tie down the first purse-string and double-secure the aortic cannulation site with a figure of eight 4-0 polypropylene suture, and close the wound in layers according to the standard protocols. In this representative study, compared to the full sternotomy approach, a right anterior mini-thoracotomy necessitated significantly longer ischemic, cardiopulmonary, and operative times, while the proportion of biological versus mechanical valve substitutes did not differ between groups.
In spite of the longer operation times, the right anterior mini-thoracotomy did not increase the rate of major adverse cardiovascular and cerebrovascular events in comparison to the full sternotomy incision. Patients undergoing right anterior mini-thoracotomy also tended to be extubated earlier, and stayed for a shorter period in the intensive care unit than those operated through full sternotomy, although these differences were not statistically significant. Compared to full sternotomy, right anterior mini-thoracotomy patients also had a significantly reduced need for pain medication and transfusion requirements, a reduced incidence of new onset atrial fibrillation and deep wound infection, and a reduced global length of hospital stay.
In addition, right anterior mini-thoracotomy patients reported greater satisfaction with the cosmetic results. Once mastered, this technique can be completed in four hours if it is performed properly. Following this protocol, other heart valves, including the mitral and the tricuspid, can be operated by this approach.
After its introduction, this technique paved the way for other minimal access approaches in both adult and pediatric open heart surgeries. After watching this video you should have a good understanding of how to perform a aortic valve replacement through a right anterior mini-thoracotomy. Don't forget that performing aortic valve replacement through a right anterior mini-thoracotomy can be very challenging, and that each step should be meticulously completed before beginning the next one.
