Ann Thorac Surg 1995;59:621-625
© 1995 The Society of Thoracic Surgeons
Autologous Reconstruction of Pulmonary Trunk at Reoperation After Extracardiac Conduit Repair
Makoto Ando, MD,
Yasuharu Imai, MD,
Shuichi Hoshino, MD,
Kazuaki Ishihara, MD
The Heart Institute of Japan, Tokyo Women's Medical College, Tokyo, Japan
Accepted for publication November 8, 1994.
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Abstract
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Between 1991 and 1993, 5 patients underwent reoperation for critical stenosis of extracardiac conduit. Indication for extracardiac conduit repair was pulmonary truncal atresia in 3 patients and coronary anomaly including single left coronary artery and left anterior descending artery from right coronary artery in 2 patients. Age at reoperation ranged from 8 to 23 years (mean, 16.2 years). Preoperative systolic pressure ratio of right to left ventricles ranged from 0.83 to 1.05 (mean, 0.93), with the pressure gradient across the conduit ranging from 52 to 100 mm Hg (mean, 74.4 mm Hg). At reoperation, stenotic conduit was completely removed and central pulmonary artery was extensively mobilized. In 4 patients who had a relatively short distance (15 to 25 mm) between the pulmonary arterial stump and the right ventriculotomy incision, the distal pulmonary arterial stump was anastomosed directly to the cranial margin of the right ventriculotomy incision to serve as a floor made of autologous tissue. In 1 patient with a long distance (40 mm), right ventricular–pulmonary arterial continuity was restored with a tailored autologous pericardial tube. There were no early or late deaths. Postoperative catheterization study revealed a satisfactory reduction of right ventricular pressure with the systolic pressure ratio ranging from 0.42 to 0.51 (mean, 0.47) and the pressure gradient across the right ventricular outflow tract ranged within 13 mm Hg (mean, 5 mm Hg). Restoration of right ventricular–pulmonary arterial continuity was successfully achieved by introducing the concept of autologous tissue repair even at reoperation instead of the insertion of new extracardiac conduit in patients with tetralogy of Fallot after extracardiac conduit repair.
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Introduction
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Repeated replacement of conduit after extracardiac conduit repair seems mandatory as long as a tubular graft made of either synthetic material or bioprosthesis is used. In an attempt to avoid further reoperation, we began using autologous tissue for reconstruction of right ventricular outflow tract. Since we introduced the technique of anastomosing distal pulmonary arterial stump directly to right ventriculotomy incision for the establishment of right ventricular–pulmonary arterial (RV–PA) continuity in pulmonary atresia with tetralogy of Fallot in 1992, we have extended this idea of autologous tissue reconstruction to other diseases such as atrioventricular discordance, double-outlet right ventricle, persistent truncus arteriosus, and transposition of the great arteries. In this report, we describe the short-term results of this technique applied even at reoperation for failed extracardiac conduit after extracardiac conduit repair.
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Patients and Methods
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From January 1970 through December 1993, 282 patients, including 26 reoperative cases, underwent extracardiac conduit repair for the establishment of RV–PA continuity at the Heart Institute of Japan. Since June 1992, 5 patients with tetralogy of Fallot underwent reoperation for deteriorated conduit without using extracardiac conduit. There were 3 male and 2 female patients. Ages ranged from 8 to 23 years (mean, 16.2 years), and body weight ranged from 19 to 68 kg (mean, 43.8 kg) at reoperation. The indication for extracardiac conduit repair had been pulmonary truncal atresia in 3 patients and anomalous coronary artery in 2, including single left coronary artery in 1 patient and left anterior descending coronary artery from right coronary artery in another patient (Table 1
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Surgical Techniques
After revision of median sternotomy, pericardial adhesion was dissected with utmost care. The central pulmonary artery and both pulmonary branches then were dissected with utmost care and mobilized extensively. After the institution of cardiopulmonary bypass, stenotic conduit was completely removed. In 4 patients who had a relatively short distance between the pulmonary arterial stump and the right ventriculotomy incision, the distal pulmonary arterial stump was anastomosed directly to the cranial margin of the right ventriculotomy incision to serve as a floor made of autologous tissue, and the right ventricular outflow tract was enlarged by placement of a monocuspid or bicuspid outflow patch. In 1 patient with a long distance, autologous pericardium was procured and anastomosed to pulmonary arterial stump distally, and to the cranial end of the right ventriculotomy incision proximally. The lateral edges then were sewn to each other anteriorly to form a tube, which was completed by anterior patch. All procedures were completed under ventricular fibrillation (Fig 1).
Follow-up
The length of follow-up ranged from 11.1 to 18.1 months (mean, 14.4 months). Four patients were subjected to postoperative catheterization 13 to 329 days (mean, 96 days) after reoperation. The parameters measured were compared with preoperative data to assess the improvement in right ventricular function, and angiograms obtained before and after reoperation were compared to examine the morphologic changes associated with the procedure.
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Results
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There were no early or late deaths. The interval between the first operation and reoperation ranged from 6.8 to 14.5 years (mean, 11.5 years). All patients were asymptomatic before reoperation. The distance between the right ventriculotomy incision and the pulmonary arterial stump estimated from retrospective review of the preoperative angiogram was compared with the operative procedure performed in each patient. In 4 patients who underwent the direct anastomosis technique, the distance ranged from 15 to 25 mm, whereas in 1 patient the technique of interposition of autologous pericardium it measured 40 mm.
One patient frequently showed a ventricular tachy- arrhythmia of unknown cause on the first postoperative day. She therefore required cardiopulmonary support for 7 days until a stable hemodynamic condition was obtained. Electrocardiogram showed no changes in ST-T level before and after the incidents. Compressive effect of the right ventricular outflow tract on the underlying coronary artery was not identified in the postoperative angiogram, which is described later. It could have been due to the problem of extracorporeal circulation management during operation, although the exact reason remains unknown.
In the remaining 4 patients, the postoperative clinical course was uneventful. The endotracheal tube was removed within the first postoperative day and inotropic support was completely discontinued within a week after the operation.
Catheterization data obtained before and after the operation are shown in Table 2. The data revealed a reduction of right ventricular pressure with the right-to-left ventricular systolic pressure ratio from 0.87, 0.83, 0.97, and 1.05 preoperatively to 0.42, 0.50, 0.43, and 0.51 postoperatively, and similarly, the pressure gradient across the right ventricular outflow tract changed from 105, 80, 100, and 60 mm Hg preoperatively to 4, 13, 3, and 0 mm Hg postoperatively. Postoperative catheterization data on right ventricular function were obtained from 3 patients. In 2 patients (patients 1 and 4), right ventriculogram revealed satisfactory preservation of ventricular function with the right ventricular end-diastolic volume index reduced from 148% and 151% of normal value preoperatively to 133% and 97% of normal value postoperatively, and right ventricular ejection fraction improved from 0.49 and 0.39 to 0.58 and 0.47. In one patient (patient 2), the right ventricular end-diastolic volume index unfavorably increased from 104% of normal value to 123% of normal value and right ventricular ejection fraction dropped from 0.45 to 0.36, although the cardiac index showed no change before and after operation (4.0 L • min-1 • m-2). Postoperative right ventriculogram revealed morphologic changes in the pulmonary artery from T configuration preoperatively to Y configuration postoperatively (Fig 2), but distortion such as angulation in the arterial tree was not present. In 2 patients with anomalous coronary artery, postoperative aortogram revealed no compressive effect of the technique on the underlying coronary artery in either patient (Fig 3). In patient 5, who required cardiopulmonary support after reoperation, decubitus developed on the sacral region after operation; this patient underwent plastic surgery thereafter. She was discharged from the hospital 113 days after operation. In the remaining 4 patients, hospital stay ranged from 14 to 28 (mean, 20.3) days after operation, and all of them (including patient 5) are in New York Heart Association functional class I without any aid of inotropic agents at the time of last follow-up.
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Fig 2. . Representative right ventriculogram of direct anastomosis technique obtained before (Pre) and after (Post) reoperation. (A) Anteroposterior view. Arrows show the site of conduit obstruction. (B) Lateral view.
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Fig 3. . Left ventriculogram in patient with left anterior descending coronary artery from right coronary artery: (A) lateral view; (B) anteroposterior view. No compressive effect was noted on the left anterior descending artery underlying the right ventricular outflow tract (arrows).
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Comment
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In an effort to improve the durability of extracardiac conduits used for the establishment of RV–PA continuity, various types of materials have been used; however, the ideal conduit has not yet been developed. This repair is difficult because of the incompatibility of foreign materials used for the conduit and the by-products generated in the course of endeavors to reduce their antigenicity.
Fabric grafts commercially available today lack successful endothelial healing properties, and thus the results of these materials are not convincing in the right heart position as they are in the aortic position. Among them, the Dacron graft in combination with a bioprosthetic valve has gained the most widespread popularity. However, as is described in many articles, its clinical performance has proved to be unsatisfactory [1–6]. The development of obstruction of Dacron graft used in the extracardiac conduit occurs primarily because the fibrous anchorage of the intimal peel onto the graft is so loose that it detaches easily from the luminal wall. This phenomenon was described in detail by Agarwal and associates [7, 8] and seems to be the inherent tendency of the synthetic material.
Recently, allografts have taken the place of the Dacron graft [9–12] and have become the most widely used material for extracardiac conduit repair. Nevertheless, the viability of donor endothelial cells is doubtful even in this material. We predict that the loss of confluent layer of endothelial cells may be followed by disorganization of underlying collagen fibers, finally contributing to the deterioration of the graft. Gavin and colleagues [13] report that even if preserved by a less toxic method, eventual histologic changes in this material may be essentially the same as those in chemically treated ones.
In an attempt to avoid further reoperation, our search was directed toward the reconstruction of right ventricular outflow tract with autologous tissue. Danielson and co-workers [14] reported the technique of using the conduit bed after the removal of obstructed conduit at reoperation after extracardiac conduit repair. On the other hand, Jacobs and associates [15] reported using flaps of autologous tissue, including truncal tissue, pulmonary artery, left appendage, and right appendage for the establishment of RV–PA continuity in infants. In addition to these techniques, the most fascinating one is that reported by LeCompte and colleagues, [16] in which pulmonary artery is anastomosed directly to right ventricular incision to establish RV–PA continuity in type III transposition of the great arteries.
Since 1992, we have applied this technique to the establishment of the right ventricular outflow tract at reoperation in patients with tetralogy of Fallot, which once required the extracardiac conduit to accomplish the reconstruction. However, there are some potential drawbacks associated with this procedure. Forced retraction of the distal pulmonary arterial stump may cause unfavorable distortion of the pulmonary artery, which brings about disturbance of the pulmonary blood flow. Compression of the adjacent architecture, such as underlying coronary artery on the right ventricular outflow tract, may yield miserable results. To avoid these problems, we try to mobilize pulmonary arteries as widely as possible, thus maintaining the curvature of the pulmonary arterial tree smoothly even after the retraction. If the retraction seems to bring about the distortion of the pulmonary artery, free autologous pericardium is procured to interpose between right ventricle and pulmonary artery instead of inserting an extracardiac conduit. This decision was made while in the operating room.
According to our treatment policy, either of these techniques could be applied exclusively for diseases with RV–PA discontinuity after June 1992. The satisfactory reduction of the pressure gradient across the right ventricular outflow tract on postoperative catheterization data strengthened the validity of our choice. Additionally, in this series of patients a monocuspid or bicuspid valve (made of autologous pericardium) was mounted on the inner surface of the anterior patch. In patients in whom conduit stenosis has developed in the long term, predictably there exists some decline in right ventricular function. Moreover, even in patients whose pulmonary arteries are fully grown, like this set of patients, it is likely that elevations in pulmonary vascular resistance do occur in the acute phase of the postoperative period. Therefore, it would be useful to mount at least a monocuspid valve on the outflow tract to prevent afterloading on the right ventricle, at least in the acute phase.
A report by Sawatari and co-workers [17] described the tissue viability of aortic strips and colonization of aortic elements on free pericardial autograft reimplanted in descending aorta of growing lambs demonstrated by microscopic investigation. This suggested tissue viability even if it is once cut off and reimplanted, which is indeed an encouraging result for our treatment policy.
Restoration of RV–PA continuity with autologous tissue could be achieved safely by proper judgment in choosing a technique. Our early experience with these 5 patients was acceptable, and we believe that reoperation-free conditions can be incorporated in the reconstructive procedure of pulmonary trunk in the field of congenital heart defects by autologous tissue repair.
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Footnotes
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Address reprint requests to Dr Ando, 8-1 Kawada-Cho, Shinjyuku-Ku, Tokyo, 162 Japan.
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References
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- Kirklin JW, Blackstone EH, Maehara T, et al. Intermediate-term fate of cryopreserved allograft and xenograft valved conduits. Ann Thorac Surg 1987;44:598–606.[Abstract]
- Jonas RA, Freed MD, Mayer Jr JE, Castaneda AR. Long-term follow-up of patients with synthetic right heart conduits. Am J Cardiol 1985;72(Suppl 2):77–83.
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- Danielson GK, Downing TP, Schaff HV, Puga FJ, DiDonato RM, Ritter DG. Replacement of obstructed extracardiac conduits with autogenous tissue reconstructions. J Thorac Cardiovasc Surg 1987;93:555–9.[Abstract]
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- Sawatari K, Kawata H, Arminger LC, Jonas RA. Growth of composite conduits utilizing longitudinal arterial autograft in growing lambs. J Thorac Cardiovasc Surg 1992;103:47–51.[Abstract]
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Abstract
Introduction
