Porcine-valved Dacron Conduits in Fontan Procedures

Transcription

1 Porcine-valved Dacron Conduits in Fontan Procedures K. B. Prenger, M.D., J. Hess, Ph.D., M.D., A. H. Cromme-Dijkhuis, Ph.D., M.D., and A. Eijgelaar, Ph.D., M.D. ABSTRACT From a series of 52 Fontan procedures between 976 and 98.4, the cases of the 27 consecutive patients who received a porcine-valved conduit were reviewed. There were 5 hospital deaths among these 27 patients. Follow-up ranges from ll years 9 months to 3 years 9 months. At follow-up, no conduit-related complications could be demonstrated. There were no signs of valvular stenosis, exuberant peel formation, or calcification of the conduit in any of the patients. To date, there has been no need to replace any of the porcine-valved conduits. Cumulative survival (including hospital deaths) is 7% at 0 years. In conclusion, we believe that the porcine-valved conduits have functioned very satisfactorily over time. The Fontan operation and its various modifications have proven to be a good palliative procedure for numerous congenital malformations [l-4. The atriopulmonary connection can be established in these patients in various ways: by () a direct anastomosis of the right atrial appendage to the pulmonary artery; (2) a composite conduit of a flap of the right atrium and a Dacron patch as a roof; (3) a Dacron nonvalved conduit; (4) a conduit consisting of an aortic homograft; and (5) a valved conduit with a porcine bioprosthesis. Many reports dealing with extracardiac conduits point to the conduit obstruction that can occur after a while [5-7. Therefore, we decided to review the cases of patients in whom porcine-valved Dacron conduits were used. Material and Methods From May, 976, to May, 984, 52 Fontan procedures were performed in our hospital. Twenty-seven patients received a porcine-valved conduit in a modified Fontan procedure. They form the study group for this review. These were 7 male and 0 female patients. The patients had a variety of complex congenital cardiac malformations. Most were classified as tricuspid atresia, pulmonary atresia with intact ventricular septum and a hypoplastic right ventricle, double-inlet single ventricle, and double-outlet right ventricle and a hypoplastic left ventricle ( patient) (Table ). Twenty of the 27 patients needed one or more palliative procedures From the Departments of Cardiopulmonary Surgery and Pediatric Cardiology, State University Hospital Groningen, Groningen, The Netherlands. Accepted for publication May 6, 988. Address reprint requests to Dr. l'renger, Department of Cardiopulmo- MY Surgery, University Hospital Maastricht, PO Box 98, 620 BX Maashicht, The Netherlands. prior to the Fontan procedure, mainly modified Blalock- Taussig or shunts. Operation was indicated in each patient because of cyanosis or progressive exercise intolerance, or both. The age of the patients at the time of the Fontan operation ranged from 23 months to 7 years 5 months (mean age, 7 years month) (Table 2). In 26 patients a Hancock porcine bioprosthesis was used and in patient, an Ionescu-Shiley bioprosthesis. The sizes of the bioprostheses are shown in Figure. Operative Technique After a median stemotomy, cardiopulmonary bypass was established with selective cannulation of both cavae. Previous and shunts were closed directly after the institution of cardiopulmonary bypass. Deep to moderate hypothermia and Bretschneider cardioplegic solution were used in all patients. If necessary, reduced flow or circulatory arrest was also used. The atrial septa defects and the tricuspid orifice, if patent, were closed separately with a Dacron patch. The tricuspid orifice in patient was pinpoint but patent. The pathway was considered too minor to close at the time of the Fontan operation. However, the postoperative course necessitated closure at a second stage 5% months after the initial Fontan operation. In all 27 patients, continuity between the right atrium and the pulmonary artery was established by a Dacron graft containing a porcine bioprosthesis. In patients without pulmonary atresia, the pulmonary artery main stem was closed by ligation or was cut and oversewn. Postoperatively all patients received acenocoumarine for 3 to 6 months to prevent thrombosis at the Dacron graft before complete endothelialization. To evaluate the hemodynamic result, an invasive study was scheduled year after the Fontan operation. Furthermore, echocardiographic and Doppler flow studies were performed in all patients available for follow-up between December, 986, and February, 987. Results Five of the 27 patients died in the immediate postoperative period (see Table 2). Four died of cardiac failure, which was part of multiorgan failure in 2. In patient, a valved conduit that was probably too small was inserted. This patient was of the first in the series to have repair. Persistent hemorrhage led to restemotomy in 3 patients. Patch dehiscence of the tricuspid orifice occurred in 2 patients, both of whom had reoperation for closure of the orifice month and 2 months after the initial Fontan procedure. Surgical third-degree atrioventricular 526 Ann Thorac Surg 46:526-5, Nov 988. Copyright by The Society of Thoracic Surgeons

2 527 Prenger et a Porcine-valved Conduits in Fontan Procedures Table. Main Diagnosis in 27 Patients Given a Porcine Valved Atriopulmonay Conduit Diagnosis Tricuspid atresia 3 Tricuspid atresia + PA or PS 3 Tricuspid atresia + dextrocardia with or without 2 Pulmonary atresia with intact ventricular septum 3 + hypoplastic RV Pulmonary atresia + hypoplastic RV + giant Pulmonary atresia + D- + hypoplastic LV Pulmonary stenosis + hypoplastic RV + Double-outlet right ventricle + hypoplastic LV Double-inlet single ventricle + corrected + PS or PA Double-inlet single ventricle + D- + PS or PA No. of Patients PA = pulmonary atresia; PS = pulmonary stenosis; = transposition of great arteries; RV = right ventricle; = ventricular septa defect; D- = dextrohansposition of great arteries; LV = left ventricle. block necessitated permanent pacemaker implantation in 2 patients, and 2 other patients with a congenital third-degree atrioventricular block also had pacemaker implantation after the Fontan operation. Five patients sustained protein-losing enteropathy. In, a pinpoint tricuspid orifice was left open at the initial Fontan operation. Subsequent closure of the orifice relieved the symptoms. Four other patients needed treatment with medium-chain fatty acids and diuretics [8]. Twenty-two patients were available for follow-up. Follow-up ranges from years 9 months to 3 years 9 months (mean follow-up, 6 years 4 months). Cumulative survival is shown in Figure 2. It appears to be 7% at 0 years with a mean survival of 98 months (% 2 months [ % standard error]) as a product-unit (Kaplan-Meier) estimate. Three patients died 5 months, 38 months, and 50 months postoperatively. The first patient was in good health in terms of cardiac status; he died of a ruptured cerebral aneurysm. In the third patient, no specific cause of death could be found. This patient had very poor left ventricular function, and possibly embolization from the left ventricle had occurred. In retrospect, we now would not consider a Fontan procedure for such a patient. The second patient sustained multiple pulmonary emboli, probably caused by recurrent atrial arrhythmias. Both the second and third patients had protein-losing enteropathy and were treated with a low-fat medium-chain triglyceride diet. A postmortem examination of the first and third patients was performed. In both instances it appeared that the valve leaflets had completely disappeared (atrophied). Both conduits were widely patent and showed no sign of peel formation proximal or distal to the valve or at the anastomotic sites , m 0- c z Y 8, g 8 6- P 4, 2, 0 0 SURVIVORS HOSPITAL DEATHS LATE DEATHS SEE OF BIOPROSTHESIS Fig. Sizes of the valves used in the atriopulmonury conduits. Twenty (9%) of the patients who were discharged from the hospital after the Fontan operation had an invasive study year after the operation. The parents of 2 patients withheld their consent to an invasive follow-up study, but both patients were available for noninvasive studies and are not lost to follow-up. Right atrial pressures and conduit pressures ranged from 8 to 20 mm Hg (median, 2 mm Hg). In 2 of the patients, no gradient across the conduit could be demonstrated. In only patient was a pressure gradient of 2 mm Hg noted at the proximal anastomotic site. The conduit and the valve appeared to be normal in this patient. The cardiac indices ranged from.7 to 3.3 L/min/m (mean, 2.04 L/min/ m ; median, 2.2 L/min/m ). Functionally all but patient are in a good state and are in New York Heart Association Class I or. The patient with the gradient is functionally in Class. However, reoperation is not yet under consideration. In 986, all surviving 9 patients underwent an echocardiographic study. In all patients the valve leaflets could be visualized and were found to open directly after atrial contraction. One patient showed flow disturbance and spectral broadening in the conduit at pulsed Doppler echocardiography; this was the patient who appeared at the invasive study to have moderate stenosis at the proximal anastomotic site with a gradient of 2 mm Hg between the right atrium and the right pulmonary artery. The patient who underwent a Fontan repair for a double-outlet right ventricle with a hypoplastic left ventricle and transposition of the great arteries, appeared to have a grade 6 systolic murmur with conduction over the precordium and the back when seen at the regular outpatient checkups. Echocardiographically a stenosis was demonstrated in the aortic outflow tract with an estimated pressure gradient of 60 mm Hg. An invasive study was performed and confirmed the noninvasive diagnosis. No stenosis could be demonstrated in the conduit; valve leaflets opened (and closed) freely. In January, 987, 3 years 5 months after the initial

3 ~ 528 The Annals of Thoracic Surgery Vol 46 No 5 November 988 Table 2. Patient Profile for Valved Conduits Size of Patient Age at Modified Conduit Follow-up No., Sex Diagnosis Palliation Fontan Operation (mm) (mo) Result. M 2. F 3. F 4. M 5. M 6. M 7. F 8. M 9. F 0. F. M 2. M 3. M 4. M 5. F 6. F 7. M 8. M 9. F 20. M 2. M. M 23. F 24. M. M 26. F 27. M UVH, PS, D-, ASD TA UVH, PS, corrected, ASD, situs inversus TA, ASD, UVH, infundibular PS, corrected PS, hypoplastic RV, TA, PA, UVH, valvular PS, D- TA, PS, ASD, dextrocardia UVH, PS, corrected, ASD UVH, TA,, ASD, dextrocardia PA, hypoplastic RV, ASD,, giant, PS UVH, TS, PS,, ASD PA, intact VS, hypoplastic RV TA, PA TA, PA, PA, D-, hypoplastic LV, TA, hypoplastic RV, ASD, PA, hypoplastic RV, intact vs UVH, valvular PS, corrected, ASD DORV, hypoplastic LV, D- TA, PA, ASD, PA, hypoplastic RV, intact VS, ASD. UVH, single AV valve, corrected, ASD UVH, single AV valve, valvular PS, D-, ASD UVH, valvular PS, D- Glenn Rashkind, Pulmonary artery banding, Rashkind,, Brock Rashkind Pulmonary artery banding x 2, Banding, 6yr5mo 6yr0mo 5yr8mo 5yr9mo 8 yr 0 mo 6yr8mo 5yr6mo 6yr8mo 0 yr 3 mo 7yrmo 0 yr 6 mo 3 Yr yr9mo 5yr4mo 5yrlmo 4yrmo 23 mo 0 yr mo 3yr8mo 3yr7mo 4 yr 0 mo 5yr8mo 6yr5mo 7yr mo 7 yr 5 mo 9yr7mo 5yr Hospital ceath UVH = univentricular heart; PS = pulmonary stenosis; D- = dexhotransposition of great arteries; ASD = atrial septal defect; TA = tricuspid ahesia; = transposition of great arteries; = ventricular septal defect; RV = right ventricle; PA = pulmonary atresia; TS = tricuspid stenmis; VS = ventricular septum; LV = left ventricle; DORV = double-outlet right ventricle.

4 529 Prenger et al: Porcine-valved Conduits in Fontan Procedures 0 I I I I I MONTHS OF FOLLOW UP Fig 2. Cumulative survival after Fontan operation with a porcinevalved Dacron conduit ( ) (N = 27). Fontan operation, reoperation was performed. Muscular bands that probably were the ventriculo-infundibular fold, and two huge trabeculae from the ventricle were found. Resection of these structures released the outflow tract obstruction. The postoperative course was uneventful. Comment Right heart conduits are alleged to be prone to exuberant peel formation [5, 7, 9-]. Most of these reports, however, deal with a mixed group of right heart conduits with right atrium-pulmonary artery connections, right atrium-right ventricular infundibulum connections, and right ventricle-pulmonary artery connections. From these reports it is difficult to assess how the right atrium-pulmonary artery conduits functioned in the long run. Only a report by Gale and co-workers [2] suggested even more florid peel formation after Fontan procedures than in conduits from the right ventricle to the pulmonary artery. The type of connection (e.g., right atrium to pulmonary artery or right atrium to right ventricular infundibulum) seems to have some bearing on the occurrence of peel formation [3]. Geha and associates [4] found no conduit or valve obstruction in a small group of patients who underwent a modified Fontan correction, but they did note valve degeneration and obstruction in conduits that had been subject to higher pressures. Our study concerns only right atrium-pulmonary artery conduits. Obstruction of valved conduits can take place at various sites, that is, the proximal anastomosis, the valve, or the distal anastomosis, and has various causes: thrombosis [5], exuberant peel formation [5, 9, detachment of intima peel [6, 7, calcification of the Dacron conduit, calcification of valve leaflets [5], or suboptimal technique [MI. It is interesting to note that in a recent study [ll] of a large group of patients with all sorts of extracardiac conduits, it appeared that obstruction of a conduit occurred primarily in the Dacron graft rather than at valve level. In only patient did we have a mild obstruction. It was not due to peel formation or calcification, but to narrowing of the proximal anastomosis, which was probably caused by concentric scarring. Except for meticulous surgical technique, some of the factors mentioned that can lead to conduit malfunction can be influenced. For example, detachment of a formed peel can possibly be prevented by the use of a highporosity knitted Dacron conduit instead of a low-porosity woven conduit [5, 9,20. However, the former conduit can cause troublesome blood loss in the immediate perioperative period and hence cannot be considered the material of choice in this particular operation. The effect of acenocoumarine derivatives (Sintrom, warfarin sodium) on calcification of porcine valves was stressed by Stein and colleagues [2]. Inhibition of the synthesis of gamma-carboxyglutamic acid by acenocoumarol may prevent calcification. We have given all patients acenocoumarol for at least 3 months and have not seen any calcification to date. Whether the administration of acenocoumarol has contributed substantially to the favorable long-term results in this group of patients is likely, but difficult to prove. We used porcine valves in the patients in this study, and no complications attributable to the valves have occurred. Fontan and co-workers ( used aortic homograft valves in the conduits and have had good longterm results. In a recent evaluation of extracardiac conduits [, major differences between homograft and xenograft valved conduits could not be demonstrated. On the other hand, in many reports [6, 2, 8, 23 it has been shown that a valveless connection may give similar long-term results. The actuarial survival (including the early deaths) is similar to the actuarial survival reported by Stefanelli and associates [23] in a study of early and medium-term results in the treatment of single ventricle. In spite of many reports that suggest unfavorable me-

5 5 The Annals of Thoracic Surgery Vol 46 No 5 November 988 dium and long-term results when porcine-valved conduits are used as extracardiac conduits, we have not been able to show any untoward effect of the use of these conduits. This is exemplified by the fact that to date, no conduit has had to be replaced. Although we are very aware that the years to come are critical, we believe that in retrospect these conduits have functioned very satisfactorily. We would not use a porcine-valved conduit in every Fontan operation (as is clear from the fact that in 52 Fontan operations, a valved conduit was used in only 27 patients), but we do not agree with others who caution against its use. References. Fontan J, Baudet E: Surgical repair of tricuspid atresia. Thorax 26:240, Yacoub MH, Radley-Smith R Use of a valved conduit from right atrium to pulmonary artery for "correction" of single ventricle. Circulation WSuppl363, Trusler GA: Results of right atrial to right ventricular and right atrial to pulmonary artery conduits for complex congenital heart disease. Ann Surg 92382, Eijgelaar A, Hess J, Hardjowijono R, et al: Experience with the Fontan operation. Thorac Cardiovasc Surg 63, Ciaravella JM, McGoon DC, Danielson GK, et al: Experience with the extracardiac conduit. J Thorac Cardiovasc Surg 78:920, McGoon DC, Danielson GK, Puga FJ, et al: Late results after extracardiac conduit repair for congenital cardiac defects. Am J Cardiol49:74, Stewart S, Manning J, Alexson C, Hams P: The Hancock external valved conduit. J Thorac Cardiovasc Surg 86:562, Hess J, Kruizinga K, Bijleveld CMA, et al: Protein-losing enteropathy after Fontan operation. J Thorac Cardiovasc Surg 88606, Agarwal KC, Edwards WD, Feldt RH, et al: Clinicopathological correlates of obstructed right-sided porcine-valved extracardiac conduits. J Thorac Cardiovasc Surg 8:59, Schaff HV, DiDonato RM, Danielson GK, et al: Reoperation for obstructed pulmonary ventricle-pulmonary arterr conduits. J Thorac Cardiovasc Surg 88334, 984. Bull C, Macartney FJ, Horvath P, et al: Evaluation of longterm results of homograft and heterograft valves in extracardiac conduits. J Thorac Cardiovasc Surg 942, Gale AW, Danielson GK, McGoon DC, et al: Fontan procedure for tricuspid atresia. Circulation 629, Gale AW, Danielson GK, McGoon DC, Mair DD: Modified Fontan operation for univentricular heart and compbcated congenital lesions. J Thorac Cardiovasc Surg 78:83, Geha A, Laks H, Stansel HC, et al: Late failure of porcinevalved heterografts in children. J Thorac Cardiovasc Surg 78:35, Mair DD, Fulton RE, Danielson GK: Thrombotic occlusion of Hancock conduit due to severe dehydration after Fontan operation. Mayo Clin Proc 53:397, DeLeon SY, Idriss FS, Ilbawi MN, et a Neointimaob:itruction of Carpentier-Edwards valved conduit in two pa ients with modified Fontan procedure. Ann Thorac Surg 34586, Ben-Shachar G, Nicoloff DM, Edwards JE: Separation of neointima from Dacron graft causing obstruction. J Tliorac Cardiovasc Surg 868, Cleveland DC, Kirklin JK, Naftel DC, et a Surgical Teatment of tricuspid atresia. Ann Thorac Surg 38:447, Haverich A, Oelert H, Maatz W, Borst HG: Histopathological evaluation of woven and knitted Dacron graffs for right ventricular conduits: a comparative experimental sludy. Ann Thorac Surg 37404, Jonas RA, Freed MD, Mayer E Jr, Castaneda AR: Long-term follow-up of patients with synthetic right heart conduits. Circulation 72:Suppl277, Stein PD, Riddle JM, Kemp SR, et al: Effect of warfarin on calcification of spontaneously degenerated porcine bioprosthetic valves. J Thorac Cardiovasc Surg 90:9, 985. Fontan F, DevilIe C, Quaegebeur J, et a Repair of tricuspid atresia in 00 patients. J Thorac Cardiovasc Surg 85x27, Stefanelli G, Kirklin JW, Naftel DC, et a Early and iitermediate-term (0-year) results of surgery for single ventricle. Am J Cardiol 54.8, 984