Freestyle(R) Aortic Root Bioprosthesis: Modified Subcoronary Insertion Technique

Modified Subcoronary Implantation

Aortotomy
Partially transect the aorta in a horizontal fashion 1.5 to 2 cm above the right coronary. Looking inside the aorta, extend the incision to the left ending 1.5 to 2 cm above the left coronary ostia, and to the right, ending 1.5 to 2 cm above the left non-coronary commissure post.

Tack back the ascending aorta for visualization. Visualize the root and pathology, determine the number of commissures and their symmetry. Place stay sutures through the commissures if desired for visualization.

If the aortotomy is too low, close the first incision, and make a second transverse incision at a more distal site.

Site Preparation
Completely excise the diseased valve and debride the annulus and aortic wall of calcium.

The number of commissures, their symmetry, and the location of the coronaries becomes important in determining how to seat the Freestyle® bioprosthesis for optimum implantation.

Locate the patient's left-right commissure and use this as the point of origin for implantation. Note the location and height of the coronary arteries in relation to the commissures.

TIP

• If calcification of the aortic wall is extensive in the area underneath the coronary ostia, it may be necessary to implant the Freestyle bioprosthesis using a full root technique. If the calcium is limited to the annulus and other areas of the aortic wall, sutures can be taken completely through the Freestyle bioprosthesis and native aortic wall.

Sizing
The sizer should be fitted to the plane of implantation, which will be at the lowest level (nadir) of annular tissue.

The sizer need not pass through the annulus into the ventricle. Choose the largest sizer that will sit on the nadir of the three cusps without impinging upon the sinus tissue.

Do not undersize the valve.

After the appropriate size valve is chosen, the Freestyle® bioprosthesis may be rinsed while the inflow suture line is placed.

TIPS

• If the annulus is larger than the largest available size Freestyle bioprosthesis, the annulus may be plicated to accommodate the valve. Tailoring the Patient's Anatomy.
• If the sinotubular junction is more than 2 mm greater than the patient's annulus. Tailoring the Patient's Anatomy.

Inflow Suture Line
Use the patient's left-right commissure as a point of origin to correctly seat the Freestyle® bioprosthesis. Starting there, place sequential 2-0 braided polyester sutures in a simple fashion in a horizontal plane based on the level of the nadir of the annulus.

The sutures should be in the sub-commissural muscle below the left-right commissure and in the fibrous tissue and valvular tissue below the right-non and left-non commissures.

Place the sutures approximately 2-3 mm apart starting at the level of the annulus in the muscular tissue below the left-right commissure.

TIPS

• Do not attempt to align the Freestyle commissures with the patient's native commissures unless the patient's commissures are perfectly symmetrical.
• Suture needle guides can be utilized to keep sutures organized. Place bottom inflow stitch in "B" location and then use that inflow needle to put the stitch through the bioprosthesis.
• Sutures placed in the muscle below the left-right commissure should be generous bites as the muscle tissue is friable and prone to tearing.
• Sutures placed in the conduction area may be shallow as this tissue is fibrous.

Trimming the Freestyle® Bioprosthesis
Prior to trimming the bioprosthesis, it is important to determine whether the Freestyle can be implanted with the Freestyle coronary sinuses corresponding anatomically to the patient's sinuses, or if it will be necessary to rotate the valve.

If it is determined that the bioprosthesis must be rotated, refer to: Rotating the Freestyle Bioprosthesis.

If the decision has been made to implant the valve in the orthotopic position, the left and right sinuses of the valve will be excised.

A 1 to 2 mm margin of Freestyle aortic wall should remain along the leaflet tissue and commissure posts to allow for adequate suturing.

Alternatively, the Freestyle bioprosthesis can be trimmed after it is seated.

Seating the Freestyle® Bioprosthesis
Starting at the left-right commissure, divide the sutures into equal thirds.

The first stitch in each third will then be placed through the inflow suture cuff of the Freestyle at the point corresponding to the bioprosthesis commissures. (Indicated by double green solid vertical suture markers on the sewing cuff.) This will align the Freestyle bioprosthesis symmetrically for implantation, independent of the location of the patient's commissures. (The green horizontal line at the inflow edge of the bioprosthesis indicates the area for suture placement. Do not place sutures above the dotted green line.)

The remaining sutures will be placed evenly between the respective commissural stitches into the bioprosthesis sewing cuff.Begin tying the non-coronary sinus sutures, and continue around the annulus.

TIPS

• When placing a stitch through the sewing cuff, do not completely pass the needle through the cuff until all sutures between two commissures have been inserted and even spacing has been confirmed. This allows for easy repositioning of sutures if spacing appears uneven.
  
• Leave the sutures in the muscle under the left-right commissure to be tied last. This tissue is the most friable and knots will be more secure if the valve is seated by other sutures first.
  

Outflow Suture Line
The outflow suture line is performed with a running technique with double-armed 4-0 polypropylene suture.

Begin the outflow suture line at the left coronary sinus. Start half the distance up the left-right freestanding post. Utilizing the rim of sinus tissue that remains on the Freestyle® bioprosthesis, run the suture sub-ostial up to the top of the left-non commissure.

Complete the suture line to the top of the left-right commissural post.

Perform the mirror image of the previous suture line underneath the right coronary ostia.

Recall that the larger area of the polyester covering on the Freestyle bioprosthesis will be below this suture line.

TIPS

• When running suture under the coronaries, make sure that the needle does not exit in the ostial openings.
• Place the first 3-4 stitches backhand with the needle holder placed proximally on the needle to create a sharp arch.
• Do not tack the Freestyle commissures to the patient's aorta with stay sutures. It is important to be able to move the distal end of the bioprosthesis to facilitate exposure. An assistant may pull up on the patient's aorta and move the left-right post to the side to facilitate running suture under the ostia.

Transect the remaining Freestyle® tissue of the left-right commissure and the non-coronary sinus to the height of the native aorta.

Sutures should be continued up the left-right commissural post on both sides and tied together on the outside of the aortic wall.

The two sutures at the left-non and right-non commissures are continued in a running fashion and are used to secure the upper edge of the non-coronary sinus of the Freestyle to the native aorta. They are then tied together on the outside of the aortic wall.

Aortotomy Closure
Close the aortotomy in a double-layer fashion. Use a running mattress technique for the first layer, and over and under fashion for the second layer.

TIP

• This technique ensures that the left-right commissure post is aligned correctly. The two remaining commissures will naturally fall into correct alignment, as they are fixed by their attachment to the non-coronary segment of the bioprosthesis.

The right coronary of a porcine bioprosthesis is displaced distally by the large septum of the animal. In order to strengthen that septal tissue, the polyester covering on the Freestyle® bioprosthesis extends more distally underneath the bioprosthesis right coronary.

In a small percentage of patients, this polyester covering may have the potential to interfere with the suturing of the second layer underneath the patient's right coronary ostia.

The location of the patient's coronary ostia is a critical factor in determining need for rotation of the Freestyle bioprosthesis. If the right coronary ostia is located at a level equal to or above the top of the commissures, it is not necessary to rotate the bioprosthesis.

If the ostia is lower than the height of the commissure, then it is recommended that the bioprosthesis be rotated 120 degrees clockwise. This will position the Freestyle such that the right coronary sinus of the bioprosthesis is corresponding to the non-coronary sinus of the patient.

Rotating the Freestyle® Bioprosthesis
The Freestyle bioprosthesis may be rotated 120 degrees if it is determined that the patient's right coronary ostia is located low in the sinus. Recall that the larger area of polyester covering of the Freestyle bioprosthesis is located below the porcine right coronary.

Excise the left and non-coronary sinuses of the Freestyle bioprosthesis.

Implant the valve such that the Freestyle®s non-coronary sinus is in the patient's left coronary sinus and the Freestyle®s left and right coronary sinuses are in the patient's right and non-coronary sinuses respectively. This translates to rotating the Freestyle bioprosthesis 120 degrees clockwise.

Secure the Freestyle bioprosthesis under the patient's left and right coronary ostia in the previously described method.

TIPS

• Make the decision to rotate the valve 120 degrees clockwise if the patient's right coronary ostia is located below the height of the patient's commissures.
• If the decision is made to leave the coronary button intact, it is important to reinforce these coronaries with additional sutures.

Trim the remnant of right ostia of the bioprosthesis and close the resulting opening with 4-0 Prolene® sutures. The needles should then be driven through the patient's non-coronary sinus and tied.

Complete the suture line along the patient's non-coronary sinus in the previously described fashion.

Tailoring the Patient's Anatomy
When the patient's annulus measures greater than the largest available Freestyle®, the following technique can be used:

Perform a sub-valvular annuloplasty to reduce the circumference of the aortic wall. Place the Freestyle sizer in the annulus and use as a guide for plication.

A pledgeted "U" suture is placed at the base of the commissure.

• Plicate at one, two, or three commissures as necessary to fit the desired size.
• Complete implant in previously described fashion.

If the sinotubular junction is larger than the annulus but not by greater than two valve sizes:

• Use the Root Inclusion Technique and tailor the patient's sinotubular junction to fit the crown of the Freestyle bioprosthesis.
• If the patient's sinotubular junction appears more than two valve sizes larger than the annulus, consider implanting the Freestyle bioprosthesis as a full root.

If the aortic root needs to be enlarged:

• The aortic wall may be enlarged if the non-coronary wall of the bioprosthesis appears to buckle significantly within the patient's aorta once the right and left coronary sinuses are secured.
• Make an incision down the patient's aorta in the non-coronary sinus. Close the incision in a v-shaped fashion to the back wall of the Freestyle® bioprosthesis.

Bicuspid Valve
The Freestyle® bioprosthesis can be successfully implanted in a patient with a true bicuspid valve.

After excising the diseased valve leaflets, determine the shortest distance between the left and the right coronary ostia.

Position the left-right commissure post of the Freestyle bioprosthesis in the center of the shortest distance between the left and right ostia.

If it is determined that the patient's ostia are exactly 180 degrees opposed, the Freestyle may be implanted as a full root.