THÔNG TIN TÀI LIỆU
operation, originally described by Reid and colleagues37 and popularized by Barbero-Marcial and colleagues,38 involved a direct anastomosis between the pulmonary arteries and the right ventricle, with the anterior aspect of the anastomosis being augmented with a monocusp or pericardial patch (Fig 40.20) The Brazilian series as initially reported involved seven infants aged from 2 to 9 months.38 Of these, one died early, but no late deaths were reported During a short period of follow-up, patients were functionally well, although the monocusp valve frequently became regurgitant In a series reported from Birmingham, in the United Kingdom, it was observed that mortality was similar in patients who underwent repair using a direct anastomosis, compared with those in whom a valved conduit had been used.39 However, the freedom from reintervention to the right ventricular outflow tract was greater in those having direct anastomosis Similarly, in a small series of patients from Paris, those who underwent surgery without a conduit had lower rates of reintervention and better growth of the central pulmonary arteries.40 Thus this approach may have some benefits, although further studies will be required, particularly to examine the impact of the pulmonary regurgitation, which is universal after this type of modification FIG 40.20 Repair of common arterial trunk, without a conduit (A) The pulmonary trunk is anastomosed to the right ventricle (B) The anterior aspect of the anastomosis and pulmonary trunk is augmented with a monocusp An alternative solution to overcome the limited supply of homografts has been to use alternative types of conduit Although a number of different types have been used,41,42 there has been much interest in the Contegra conduit (Medtronic) This is a heterologous bovine jugular venous graft containing a trileaflet venous valve It is available in sizes as small as 12 mm, making it potentially ideal for reconstructing the right ventricular outflow tract in neonates and infants However, there have been recent concerns with respect to the development of accelerated stenosis in the conduit, particularly when small sizes are used It appears that conduits of less than 16 mm are at higher risk of obstruction.43,44 In patients who received either a Contegra conduit or a homograft for a range of surgical procedures, multivariate, propensity-scored matching suggested that the use of the Contegra conduit independently predicted the necessity for replacement (hazard ratio of 3.7).45 Truncal regurgitation remains a significant challenge In general, regurgitation of even moderate severity should be dealt with conservatively Where severe regurgitation exists, often resulting from prolapse of a rudimentary leaflet of the truncal valve, the valve needs to be repaired, or rarely replaced In one series of 72 patients, preoperative echocardiographic assessment demonstrated no or minor regurgitation in 30, regurgitation that was mild in 25, moderate in 10, and severe in 7 A decision to perform surgery to the truncal valve at the time of truncal repair was made in 16 patients The anatomic factors associated with the need for surgery to the truncal valve included an abnormal number of valvar leaflets, which may be dysplastic, and an abnormal origin of the coronary arteries.46 Repair of the truncal valve may be performed at the time of the neonatal repair or later, often at the time of revision of the right ventricle-topulmonary conduit.47 For patients undergoing repair of the truncal valve at the time of their complete repair, data from the Society of Thoracic Surgeons indicate that early mortality is high at 30%, being particularly high in those also requiring concomitant repair of the aortic arch, when it reached 60%.48 Shortterm hemodynamic improvement is feasible, although by 10 years after surgery, the freedom from reoperation was only 23% in the largest series published to date.49 Surgical creation of a tricuspid truncal valve appeared to provide the best outcomes for these patients Successful surgical correction can also be achieved when the aortic arch is interrupted The original successful repair, described by Gomes and McGoon,50 in which the duct was left in place to supply blood to the descending aorta, is not now used At the time of complete repair, the duct and all ductal tissue must be excised The entire thoracic aorta, the pulmonary arteries, the head and neck vessels, and the duct must be thoroughly mobilized, so that the ascending and descending parts of the aorta can be joined Surgery is performed using profound hypothermia and circulatory arrest or alternatively by using the technique of continuous cerebral perfusion It has been suggested that, if the arch can be advanced and the anastomosis performed without using a patch to augment it, the requirement for reintervention may be reduced.51 Some patients may present beyond the neonatal period Surgical repair in such patients may still be possible, although preoperative cardiac catheterization to assess the reactivity of the pulmonary vascular bed is important, and careful management of the pulmonary vascular bed is essential in the postoperative period.52,53 Preoperative use of pulmonary vasodilators may allow for some remodeling of the pulmonary vascular bed in preparation for surgery
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