Drs. Pelletier and Jacobs, in a follow-up article to their Superior Cavopulmonary Anastomosis review, have now provided us with an outstanding summary of the current approaches to the “modified” Fontan procedure. This work describes the two primary techniques currently used for the “modified” Fontan operation, the lateral tunnel and the extracardiac Fontan. The superb drawings are furnished by Rachid Idriss. Rachid is the son of Farouk Idriss, who was the Chief of Pediatric Cardiac Surgery at Children’s Memorial Hospital from 1967 through 1989. The description of the procedures, the illustrations, and the Tips and Pitfalls truly give a widely encompassing knowledge-set on which to base the performance of these operations.
In my Editor’s Note there is very little that I can add to the superb technical analysis. What I would like to focus on are a few differences between the techniques that we have used at Children’s Memorial Hospital and perhaps some different approaches that may be of interest to surgeons. Certainly, there can be no argument with Dr. Jacobs’ published results of 72 consecutive Fontan operations with no mortality. My viewpoints in this note are based on observations from 159 primary Fontan operations and 109 Fontan conversions performed by myself, Dr. Constantine Mavroudis, and Dr. Robert Stewart.
Drs. Pelletier and Jacobs state that “…central venous access is not routinely used.” Our practice has been slightly different than this. We have used subclavian double- or triple-lumen central lines for essentially all of our Fontan patients. If we are unable to obtain access with a subclavian line, we then place a central line in the femoral vein. We use this for preoperative and postoperative CVP monitoring and inotrope infusion. We have noted very few complications from the use of these lines.
The authors, for the lateral tunnel approach, have used a single atrial cannula. In our patients, we have used bicaval cannulation in nearly all patients. This has been facilitated by the excellent flow characteristic of small right-angle cannulas. For the patient with an extracardiac Fontan we also use bicaval venous cannulation (not SVC, right atrial cannulation). This makes use of the cardiotomy sucker for construction of the inferior vena caval anastomosis unnecessary and results in a fairly bloodless field.
We have not used circulatory arrest, except in very complex heterotaxy patients, for the Fontan procedure. As Table 1 shows, there is a mix of use of continuous cardiopulmonary bypass and circulatory arrest in the literature. Of interest, the single paper by Mosca that compared these two actually showed better results with deep hypothermic circulatory arrest. This has also been Dr. Jacobs’ preference. It should be noted here that in the spectrum there are surgeons who perform the Fontan operation without the use of cardiopulmonary bypass, using temporary caval-atrial cannulas.1
The authors describe use of a 10-mm PTFE tube graft that is cut in half. For the lateral tunnel approach we have used PTFE patch material cut in a similar shape to the PTFE tube graft. We have also adopted the use of two small fenestrations placed in the center of the PTFE patch with the lateral tunnel technique. We have used the 2.7-mm aortic punch to create these fenestrations which tend to close on their own over a period of months.
The authors describe using transmural atrial lines at the conclusion of the procedure. We have stopped using atrial lines for two reasons. One is the risk of bleeding from the atrium at the time of line removal; the other is the risk of the line working its way out of the atrium and into the pericardial space due to the rocking motion of the heart. These two complications are difficult to deal with. As noted earlier, we have been very happy with the use of subclavian and femoral vein central lines. The authors describe using mediastinal tubes only; they then place chest tubes later if a pleural effusion should develop. In our practice we have used bilateral pleural chest tubes placed at the time of the sternotomy in nearly all patients undergoing the Fontan procedure.
Regarding the series of illustrations showing how a fenestration may be created with the use of the extracardiac Fontan, I would note that we rarely if ever use a fenestration when we use the extracardiac Fontan approach. These patients, who are all staged with a superior cavopulmonary anastomosis and then have the extracardiac Fontan performed without circulatory arrest and without cardioplegia usually have a very short period of cardiopulmonary bypass, somewhere between 30 and 45 minutes. Dr. Hanley has published his results with the extracardiac Fontan without fenestration.2
For the extracardiac Fontan, we use typically either an 18- or 20-mm Gore-Tex graft (WL Gore & Associates, Inc., Flagstaff, AZ). We prefer that the patient be at least 15 kg if possible so that this size graft can be used. If the patient has a separate entrance of the inferior vena cava and hepatic veins to the atrium as is common in patients with heterotaxy syndrome, we bevel the Gore-Tex graft so that it can encompass the multiple orifices coming into the right atrium.
Another technique difference (addition) that we have used for the extracardiac Fontan patients is the routine placement of an atrial pacing lead at the time of the primary Fontan operation. Our experience with the Fontan conversion patients and the realization that many of these patients develop atrial arrhythmias and/or sinus node dysfunction has made us cognizant of the difficulty of placing an atrial lead in a patient with an extracardiac Fontan. We have used the steroid-eluting, bipolar Medtronic epicardial leads (Medtronic, Minneapolis, MN) which are usually quite easily placed on the right atrium after weaning from cardiopulmonary bypass during the Fontan procedure. This lead is then coiled in the space between the ventricle and the diaphragm and brought up into a small pocket created posterior to the left rectus muscle. The lead can then be accessed, should it become necessary, in the years following the Fontan operation. Of course, placement of a ventricular lead would require a repeat opening of the lower portion of the sternum, but this is somewhat easier than accessing the atrium, which is usually obscured by the extracardiac graft used for the Fontan. We have, in selected patients, placed a ventricular lead also at the time of the Fontan operation with the expectation that they may, in the future, developed third-degree atrioventricular block.
In summary, these comments are meant to emphasize the fact that there are many different ways of accomplishing the “Fontan” procedure. Much like my comments on the hemi-Fontan, different surgeons using different techniques can achieve similar excellent results. The outstanding results reported by Drs Pelletier and Jacobs and the technical points they have presented will be of great benefit to surgeons performing these operations.
References
- McElhinney DB, Petrossian E, Reddy VM, Hanley FL. Extracardiac conduit Fontan procedure without cardiopulmonary bypass. Ann Thorac Surg 1998;66:1826-8.
- Thompson LD, Petrossian E, McElhinney DB, Abrikosova NA, Moore P, Reddy VM, Hanley FL. Is it necessary to routinely fenestrate an extracardiac Fontan? J Am Coll Cardiol 1999;34:539-44.
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