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The monocusp valve for RVOT reconstruction has been used for many years, but only at a few centers. This is the first large series reporting its use with the PTFE (Preclude®) pericardial membrane for the monocusp. For most surgeons, the effect of the monocusp was thought to be only short-lived. Its goal was to help the right ventricle transition from a pressure-loaded state to a volume-loaded state with ventricular dysfunction secondary to the ventriculotomy. It is interesting that its use at different congenital heart centers varies widely. This beautifully illustrated Techniques Section shows how “relatively easy” construction of the monocusp can be. The long-term follow-up with the monocusp still functioning fairly well at 2 to 5 years postoperatively is very intriguing.
Previous reviews of the monocusp, as mentioned above, have been mixed. A review from the Hospital for Sick Children published in 1996 concluded that insertion of a monocusp valve in repair of tetralogy of Fallot does not prevent short-term postoperative pulmonary insufficiency and does not improve immediate postoperative outcome [1]. In that series, the monocusp valve was created with either a commercial monocusp valve patch (Polystan, Copenhagen, Denmark) or as a patch excised from a homograft aortic valve. These valves were also constructed with autologous pericardium. In that series, there was no significant difference in the postoperative index of severity of pulmonary insufficiency comparing the different monocusp techniques with a transannular patch.
The review by Gundry and associates looked at monocusps constructed of autologous or bovine pericardium [2]. They concluded that 84% of patients had a competent pulmonary monocusp valve immediately after the operation, but by 24 months only 14% of the patients had a competent valve. No patient had monocusp stenosis. They concluded that the pericardial monocusp provided excellent early hemodynamic function but that these effects were limited in duration. In the Discussion of the presentation of that paper, Dr. David Campbell brought up the issue of the “no harm, no foul” question. That is, ” …the monocusp patch seems to function only in the early postoperative period, and pulmonary insufficiency does occur chronically in a high number of patients. Is this sufficient to justify its use?”
The recent excellent follow-up reported by Turrentine and associates with 115 patients undergoing monocusp RVOT reconstruction and followed for a mean interval of 2.6 years is quite a dramatic improvement from prior studies [3]. In that group, the intraoperative pulmonary insufficiency was graded as only mild in the monocusp group and remained mild to moderate at 2.6 years. Perhaps the use of the Preclude pericardial membrane as a specific material for the monocusp is going to prove more efficacious than the previously applied pericardial and homograft monocusp attempts.
In my own practice, I have used the monocusp sparingly. One problem that I have found is that the age at which we are doing tetralogy of Fallot repairs keeps dropping, and the use of a Gore-Tex transannular patch in a small infant sometimes leads to distortion of the pulmonary artery. For these smaller babies I personally prefer a pericardial augmentation of the pulmonary artery and the Gore-Tex only for either the transannular portion of the patch or for a small separate infundibular patch below a valve that has been spared by valvotomy and supravalvar pantaloon pericardial patch.
Re-review of this technique section has rekindled my interest in this technique and it will be interesting to see if the use of the monocusp increases given the excellent reported results with the PTFE monocusp technique from Dr. Turrentine and associates.
References
- Bigras J-L, Boutin C, McCrindle BW, et al.Short-term effect of monocuspid valves on pulmonary insufficiency and clinical outcome after surgical repair of tetralogy of Fallot.J Thorac Cardiovasc Surg 1996;112:33-7.
- Gundry SR, Razzouk AJ, Boskind JF, et al.Fate of the pericardial monocusp pulmonary valve for right ventricular outflow tract reconstruction: Early function, late failure without obstruction.J Thorac Cardiovasc Surg 1994;107:908-13.
- Turrentine MW, McCarthy RP, Vijay P, et al.PTFE monocusp valve reconstruction of the right ventricular outflow tract.Ann Thorac Surg 2002;73:871-80.
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