After aortic cross-clamp application, retrograde cardioplegia, and left ventricular venting, the aorta is transected just proximal to the clamp, with the aim of resecting all the diseased aorta distally and 1 cm above the sinotubular junction, as shown in Fig. 19.5. These guidelines allow further aortic wall resection as necessary. Also shown is dissection and mobilization of the aortic root and left main coronary artery. During the left main dissection, care is taken to avoid injury to the left atrial wall, which can be adherent to the aortic root and the course of the left main coronary artery. Figure 19.6 shows the use of electrocautery at a low setting to mobilize the course of the right coronary artery toward the epicardial surface of the myocardium. Care is also taken to avoid injuring the conal branch coronary artery, which supplies the anterior wall of the right ventricle. Surgeons have noted that damage to the conal branch coronary artery is associated with an increased incidence of postoperative ventricular arrhythmias. Also shown in ghost profile are the leaflets of the aortic valve and the relationship to the coronary artery ostia.
With these preparations, the surgeon cannow perform either the Florida sleeve operation or the David operation for congenital ascending aortic aneurysms. The indications are the same for both procedures, and the choice between them is largely dependent on the surgeon and institution based on surgical experience and outcomes, individual preference, and facility with the potential complications. Multiple judgment-based decisions are involved, including the size of the graft, the character of the aortic valve leaflets, and experience with valve leaflet repair, should it be necessary. The development of neoaortic regurgitation after root and arch repair is the most common cause of reoperation for both procedures. Their overwhelming benefit is the sparing of the aortic valve, which increases valve longevity, maintains excellent hemodynamics, and eliminates the problems of anticoagulation.
19.1.1 Florida Sleeve Operation
Once the aortic root dissection and coronary artery mobilization are performed, a Gelweave™ Valsalva graft (Vascutek Terumo, Ann Arbor, MI) is prepared. The aim of the Florida sleeve operation is to encase the aortic root to prevent any further dilatation. The graft size is of some importance. The most common sizes are 32 and 34 mm. The selection is based on the maximum diameter of the aortic root at the sinuses of Valsalva. If the measurement is 4.5 cm or less, we recommend a 30-mm graft. If the measurement is between 4.5 and 6.0 cm, we recommend a 32-mm graft. And finally, for any measurement between 6.0 and 7.0 cm, we recommend a 34-mm graft. If the measurement is above 7.0 cm, the surgeon should take intoconsideration aortic leaflet quality and anticipated function to proceed with a valve salvage operation. Sound judgment in these circumstances helps to determine and predict the long-term efficacy of this strategy. Figure 19.7 shows the Valsalva graft, which is being contoured to provide appropriately placed keyholes for the exiting coronary arteries after the sleeve is placed completely around the aortic root. The height and diameter of the keyholes are a very important part of the operation. A keyhole that is too small constricts the coronary, but one that is too large leaves too much diseased aorta exposed to the dilatation effects of the native aortopathy. In our collective experience, the most common error is to make the keyhole too low or too far upstream. Such an error can lead to compression of the cephalad portion of the exiting coronary artery. In addition to the keyhole creation, we generally remove enough Dacron circumferentially to leave 3–4 mm connected to the Valsalva portion of the graft (not shown in the drawing). The Valsalva graft has three linear black markings to delineate the commissures, which are 120° apart. In the case of unequal commissure distribution, the surgeon must adjust and mark the appropriate location. Occasionally, the surgeon encounters a bicuspid valve that is competent and likely to perform well in the future. These circumstances require adjustments for a successful valve-sparing repair. Once the keyholes are established, the graft is ready for implantation.
Figure 19.8 spatially demonstrates the placement of the subannular sutures at each commissure, which anchors the hovering graft into position. These pledgeted sutures are placed below the annulus from within the left ventricular outflow tract at the aortic-cardiac juncture and exit to the epicardial surface. They are then passed through the Dacron graft and the appropriate commissure marking. Occasionally, additional pledgeted sutures can be placed in the same manner in the non-coronary sinus, if needed to further reduce the aortic annulus. In general, annular reduction is performed if the annulus is larger than 26 mm.
In Fig. 19.9, the graft has been lowered over the entire aortic root and anchored to the aortic-cardiac juncture. Also noted are the coronary keyholes that are closed under the coronary arteries using monofilament suture. Care is taken to prevent inclusion of fibrous tissue in the suturing technique, which might cause unwanted kinking or obstruction of the coronary artery orifice. If the superior lip of the graft appears to be obstructing the orifice, a vertical incision can be accomplished to prevent stenosis. The superior portion of the graft is then trimmed to align the orifice with the superior portion of the aortic root. The aortic root is slightly pulled superiorly to closely approximate the preferred level that will be fixed during the suture line that attaches the aorta to the encircling graft (Fig. 19.10). A strip of polytetrafluoroethylene (PTFE) felt is cut to size and used to bolster the anastomosis between the superior portion of the aortic root and the neosinotubular junction and the investing graft. A running mattress monofilament suture line is performed with the felt within the aorta (Fig. 19.10). A graded dilator is then placed within the distal reconstruction, and the anastomosis is secured with the running suture (Fig. 19.11). The dilator prevents the purse-string effect that often accompanies such a repair. It then remains for the ascending aortic graft to be anastomosed end-to-end to the reconstructed proximal aorta, as shown in Fig. 19.12. The distal anastomosis to complete the repair is then performed with running suture technique (Fig. 19.13). Figure 19.14 shows the completed repair after separation from cardiopulmonary bypass (CPB) and decannulation.
19.1.2 David Valve-Sparing Operation
Figure 19.15 shows the operative aortic root exposure after aortobicaval cardiopulmonary bypass, left ventricular venting, antegrade/retrograde cardioplegia, ascending aortic aneurysmectomy, normal coronary artery anatomy. The aortic leaflets have not been involved in any dissection, and the coronary artery orifices are normally situated and without proximal stenoses or dissections. Retraction sutures are placed at the commissures, and the coronary artery buttons are harvested from their respective sinuses of Valsalva (Fig. 19.16). The non-coronary cusp aortic wall is also resected to remove as much native aortic wall as is prudent because the remaining aortic wall must accept hemostatic sutures for the neoaortic reconstruction (Fig. 19.16). An appropriately sized sinus of Valsalva graft is selected, and pledgeted sutures are placed from within the aortic outflow tract at the nadir of each coronary cusp, below the annulus, to seat the graft. An additional pledgeted suture can be placed in the non-coronary cusp if an extensive annular reduction is required for aortic valve competency (not shown). The next phases of the operation are (1) the resuspension of the remaining aortic wall and commissures to the graft, and (2) suturing with a hemostatic technique to prevent internal dissection and valve disruption. The Valsalva graft helps in the first instance, as it is manufactured to facilitate the resuspension of the aortic commissures (Fig. 19.17). Familiarity with the anatomy and experience with the amount of tension required to resuspend the valve apparatus are invaluable for this part of the operation. The other part of the seating of the valve is the hemostatic suture technique, which is performed from within the graft. In general, the running suture technique is commenced at the nadir of the sinus of Valsalva and is carried superiorly to the respective commissures (Fig. 19.17). Care is taken to place the suture line in the pathway of the scalloped aortic wall with appropriate distance between the suture placements to avoid leaks and prevent architectural tension that could cause aortic regurgitation. Each scalloped sinus is connected to the graft in this manner and tied to the top of each commissure. The remaining step in the neoaortic reconstruction is the implantation of the respective coronary artery buttons (Fig. 19.18). Before the neoaortic reconstruction, the coronary buttons should be carefully dissected to their attachments on the surface of the ventricular epicardium so the coronaries can be anastomosed to the ascending portion of the Valsalva graft without tension and without concern for postoperative myocardial malperfusion. Standard suturing techniques are used, with constant vigilance to ensure that the aortic leaflets are not damaged during the graft orifice creation or suturing. It remains only to connect the neoaorta with the ascending aorta (Fig. 19.19), while performing all the deairing maneuvers. Proper administration of myocardial protection strategies ensures prompt separation from cardiopulmonary bypass. Hemostasis is the staple of all operative and reoperative adult congenital heart operations.