1. Introduction
The surgical implantation of a valved conduit to establish the continuity between the right ventricle and the pulmonary artery made possible the repair of a huge variety of complex congenital heart defects.
Diagnoses included tetralogy of Fallot, pulmonary atresia with ventricular septal defect, truncus arteriosus, transposition with ventricular septal defect and pulmonary stenosis or atresia, and various forms of double outlet right ventricle, ventricular septal defect, with or without pulmonary stenosis [1-7].
Right ventricle to pulmonary artery valved conduits have also been used in the pulmonary autograft replacement (Ross procedure) [8,9].
Various types of prosthetic and biological valved conduit have been used through the last decades, generally with satisfactory early hemodynamic performance, but most have been abandoned because of unsatisfactory long-term results.
Since any type of valved conduit utilized for clinical application present with some problem or complication in the long-term observations, the search for the ideal conduit is still ongoing.
For the decision making process among the various valved conduits currently available for surgical implantation, several options have been to taken into consideration regarding the type of conduit.
2. Types of biological valved conduits
2.1. Dacron valved conduits
Prosthetic Dacron conduits with incorporated a biological valve, porcine, bovine, or constructed with heterologous pericardium, have been used in the early period of this type of surgery [4-7,10].
The main advantage of this type of conduits was the off the shelf availability in a complete range of sizes, which made their use very attractive and practical.
The medium term results of Dacron valved conduits were complicated by failure of the conduits due to two main reasons [5-7,10-18]:
the rapid development of thick pseudointima, causing conduit obstruction;
the rapid calcification of the glutaraldehyde preserved porcine valves, particularly in young children.
The combination of pseudointima formation and valve calcification resulted in conduit obstruction substantially reducing the freedom for conduit replacement, even in children where large size conduit had been implanted.
In favor of this type of valved conduits remained the slow and easy to detect progression of conduit stenosis, allowing timely plan of conduit replacement, facilitated by the easy shelling out of the covering pseudoadventitia, with a relatively low risk operation.
More recently aceptable long-term results have been reported with Dacron porcine valved conduits used for the right ventricular outflow tract reconstruction, particularly in patients with limited pulmonary vascular bed and high pulmonary artery pressures (19]. Even in this reported positive experience the main limit of these conduits remained their rigidity, reducing the suitability for neonates and small infants.
2.2. Aortic and pulmonary homografts
After the first report of Rastelli on 1965 [1], Ross on 1966 introduced the use of the aortic valve with aortic root and ascending aorta to obtain the continuity between right ventricle and pulmonary artery with a biological valved conduit [2].
The homografts introduced by Ross were harvested from human cadavers, generally within 24-48 after death; after dissection they were treated for few days with antibiotic solution and then stored for up to 4 weeks at 4ºC in either a balanced salt solution or in a special tissue culture medium [2].
Two changes were subsequently introduced in the homografts preparation:
homografts were sterilized by high-power irradiation
homografts were freeze dried
The combination of the two above techniques resulted in cells death, with severe damage to the collagen of the homografts, and particularly to the valve leaflets, resulting in conduit valve stenosis. As a result the use of frozen conduit with the above preparation has been abandoned, and few hospital in Europe continued to use fresh, antibiotic sterilized conduit [20,21].
Unfortunately became evident from clinical studies that homografts stored at 4ºC were gradually losing cellular viability and tissue integrity; because of these reasons the fresh homografts had to be discarded 4 to 6 weeks after preparation because not suitable for clinical utilization.
The consequence was a homograft shortage, particularly for the smaller sizes, required for implantation in small children, due to the limited number of donors.
Major progress in the utilization of homografts has been the introduction of cryopreservation technology in the preparation, particularly with the controlled freezing to the temperature of liquid nitrogen (-196ºC). This method allowed a large scale introduction of homografts in the clinical practice, despite issues related to the cellular viability of donor cells in the maintenance of the homografts durability [22-26].
The results provided by homografts on medium and long-term clinical observations were quite good, and nowadays these results are still used as comparison with any other type of biological valved conduit introduced in clinical practice [27-28].
Nevertheless the utilization of homografts present with the following issues:
the choice between aortic and pulmonary homografts
The arterial wall of pulmonary homografts is thinner (60% thickness) than the wall of aortic homografts, and the elastin concentration is less.
Because of this combination rapid dilatation of pulmonary homografts has been reported when implanted in children with pulmonary hypertension, and therefore were exposed to systemic pressure [22,23].
the rapid outgrowth of the conduit when implanted in infants and small children
Longitudinal growth can result in lengthening and narrowing. Severe degree of calcification, due to he accelerated calcium metabolism in children, can reduce the size of the homograft lumen, and also the valve leaflets can rigid and stenotic, and also calcified [29-31]. This can oblige to an early conduit replacement, even if very long-term observations have been reported, up to 21 years [32].
the reduced availability
Homografts are not always available worldwide, particularly in the small sizes frequently requested for implantation in infants and small children. The technique of bicuspidalization of adult size homografts has been utilized in order to produce homografts of small size, with decent results even recently reported at long-term follow-up [33].
the immunitary reaction
In most children where an homograft gas been implanted, humoral antibodies developed against human leukocyte antigen specific to the transplanted tissue. Host antigen recognition and antibody development may be linked to early tissue calcification and structural valved deterioration with valved conduit failure [34-36].
2.3. Bovine jugular vein
The bovine jugular vein (Contegra®, Medtronic Inc., Minneapolis, MN), containing a trileaflet valve, was introduced into clinical practice as an alternative to the use of homografts in 1999 and has provided encouraging results in several reported clinical series, with follow-up reaching more than 10 years [37-45].
Recognized advantages of the bovine jugular vein are:
structural continuity between the wall of the jugular vein of the conduit and the valve leaflets, which provides optimal hemodynamics because of the ideal effective orifice area
unlimited “off-the-shelf” availability in sizes from 12 to 22 mm diameter, representing a good alternative to the homograft shortage, particularly in the smaller sizes
availability of a long length at both inflow and outflow that obviates the need for either proximal or distal augmentation; this facilitates conduit tailoring and positioning which helps to avoid potential distortion and sternal compression
exceptional reports of antigenic reaction, due to glutaraldehyde fixation
In contrast to the good clinical results obtained in several institutions [37-45], a disturbing sequence of publications reported stenosis at the level of the distal anastomosis of the conduit, with proximal conduit dilatation, aneurysm or pseudo-aneurysm, in between 6 and 50% of patients [39,40,42,46-54].
The problem of conduit dilatation related to obstruction at the distal anastomosis has been reported as a specific complication of the bovine jugular vein [46-54].
The following mechanisms were recognized as potential causes of distal stenosis:
presence of hypoplasia and/or distal stenosis of pulmonary artery branches
discrepancy in size between conduit and pulmonary artery
surgical technique
local immunologic/inflammatory reaction
local peel formation
thrombosis
a combination of two or more of the above [55].
The impact of the surgical technique has previously been studied using Computational Fluid Dynamics comparing two types of distal anastomosis: the conventional end-to-end “
The study confirmed a larger cross sectional area in the “
These results suggested that the “elliptical” anastomosis might reduce the incidence and degree of distal stenosis, particularly for smaller conduits.
We have therefore adopted this technique for the distal anastomosis, and in addition careful rinsing (5 minutes X 3 in different saline solutions) of the bovine jugular vein before implantation to clear the glutaraldehyde to reduce the inflammatory reaction, and avoidance of oversized conduits to reduce the discrepancy between conduit and distal pulmonary artery size [45].
Using this protocol the distal conduit stenosis has became a rare observation in our experience even with the smaller conduits [45].
Early calcification of biological valved conduits is frequently reported with homografts, particularly the smaller size conduits implanted in infants or small children in the first few years of life [30,37].
In our experience early conduit calcification causing hemodynamic consequences was never observed, confirming our own previous observations and those of other researchers [39,40,42,45].
We speculate that rinsing the glutaraldehyde off before bovine jugular vein implantation reduces the calcium deposition and then prophylactic antiplatelet treatment (Aspirine 5 mg/kg/day), started immediately after surgery and continued at least for one year, may play a role.
2.5. Tissue engineered decellularized allografts
The most recently introduced biological valved conduits are the decellularized valved conduits.
The principle for the preparation is the decellularization process applied to allografts tissue to reduce the antigenicity. The mechanism of decellularization result in the removal of all native cells from the collagen tissue of the extracellular matrix, with only the collagen and elastin remaining within a structural integrity maintained. The removal of the cellular material should reduce or eliminate the immunologic response and leave the functional vascular matrix available for autogenous remodeling. The progressive migration of the recipient-specific cells into the matrix nay eventually make the graft indistinguishable from other endogenous tissues [56-61].
Different techniques have been used for decellularization, as well as they have been applied to either fresh or cryopreserved valve matrix.
The clinical reports so far were limited to a relatively short follow-up, and therefore longer periods of observation are required before considering this type of conduits as a reliable alternative to the conventional biological valved conduits.
3. Size of the biological valved conduits
The significantly higher incidence (29.4% versus 3.1%, P<0.0005) of conduit failure observed with smaller (12 and 14mm) compared to larger (16 to 22mm) bovine jugular vein conduits was directly correlated to the age and body weight at implantation, and was due to the patient outgrowing the conduit [45].
This is a recurrent problem observed with any type of biological valved conduit implanted in small patients, when a difficult balance has to be reached between the need to limit the size of the ventriculotomy, the space available in the mediastinum (particularly in heart defects with anterior aorta), and the instinct to implant the largest possible conduit to avoid early reoperation [30,37,45,62,63].
It has been reported that implantation of oversized pulmonary valved conduits doesn’t improve the durability even in infants at high risk of somatic outgrowth [30,37,64].
Since it has been demonstrated that sizing the valved conduit with a Z-score between +1 and +3 minimizes both the post-operative peak pressure gradient through the conduit and the progression of conduit valve regurgitation [64], it is reasonable to implant a biological valved conduit with a Z-score between +1 and +3 in all patients under 2 years of age.
With this regard the choice of relative small size valved conduit is limited by the reduced availability of homografts in small sizes.
4. Conclusions
The ideal biological valved conduit to establish right ventricle to pulmonary artery continuity for the surgical treatment of complex congenital heart defects doesn’t exist yet.
Particularly when the operation has to be performed in infants and small children, at least one reoperation has to be planned to replace the original conduit with a larger size conduit.
Alternative surgical options are taken in consideration, like the use of a non-valved conduit implantation to delay the conduit failure due to progressive stenosis and dysfunction of the conduit valve [65-70].
The data available in the literature show that, on a midterm basis, the use of non valved conduit may decrease the need for re-operation for right ventricular outflow tract stenosis and may promote an adequate growth of the pulmonary arteries in selected congenital heart defects, like truncus arteriosus [65-70].
In infants and smaller children where a valved conduit is required, the choice of homografts is limited by the reduced availability of small sizes, and therefore other types of biological valved conduits are utilized more frequently. Because of this reason, the surgeons still preferring the homografts have used the technique of bicuspidalization of adult size homografts to produce homografts of small size [33].
In older children and young adults, since the availability of homografts is extremely variable from country to country, at the moment there is the possibility of deciding among various alternative options, with biological valved conduits available off the shelves in all range of sizes.
At the end the choice regarding type and size of conduit depends upon the mismatch between the congenital heart defect of the specific patient, the local availability of conduits, and the personal experience of the individual surgeon.
References
- 1.
Surgical repair for pulmonary valve atresia with coronary-pulmonary artery fistula: report of a case, Mayo Clin ProcRastelli G. C Ongley P. A Davis G. D Kirklin J. W 1965 40 521 7 - 2.
Correction of pulmonary atresia with a homograft aortic valve, LancetRoss D. N Somerville J 1966 2 1446 7 - 3.
Clinical experience with the use of aortic valve homografts for reconstruction of the pulmonary artery, pulmonary valve, and outflow portion of the right ventricle, CirculationWeldon C. S Rowe R. D Gott V 1968 suppl IV):II51 61 - 4.
A valve containing Dacron prosthesis, Arch SurgBowman F. O Hancock W. D Malm J. R 1974 107 724 8 - 5.
Biological factors affecting long-term results of valvular heterografts, J Thorac Cardiovasc SurgCarpentier A Lemaigre G Robert L Carpentier S Dubost C 1969 58 467 83 - 6.
Bulterijs AHK, Becker AE, Extracardiac conduits: indications, techniques and early results, G Ital CardiolMarcelletti C Corno A. F Losekoot T. G Olthof H Schuller J. L 1980 10 1041 54 - 7.
Long term results after extracardiac valved conduits implanted for complex congenital heart disease, J Card SurgCorno A. F Giamberti A Giannico S Marino B Picardo S Ballerini L Marcelletti C 1988 3 495 500 - 8.
Replacement of aortic and mitral valve with a pulmonary autograft LancetRoss D. N 1967 2 956 7 - 9.
Glutaraldehyde-fixed bovine jugular vein as a substitute for the pulmonary valve in the Ross operation, J Thorac Cardiovasc SurgCorno A. F Hurni M Griffin H Jeanrenaud X Von Segesser L. K 2001 122 493 4 - 10.
Experience with valved conduits for repair of congenital cardiac lesions, Ann Thorac Surg;Norwood W. I Freed M. D Rocchini A. P Bernhard W. F Castaneda A. R 1977 1977 223 32 - 11.
Late results with synthetic valved external conduits from venous ventricle to pulmonary arteries CirculationBailey W. W Kirklin J. W Bargeron L. M Pacifico A. D Kouchoukos N. T 1976 56 73 9 - 12.
Surgical treatment of tetralogy of Fallot with pulmonary atresia, J Thorac Cardiovasc SurgAlfieri O Blackstone E. H Kirklin J. W Pacifico A. D Bargeron L. M 1978 76 321 35 - 13.
Late failure of porcine valve heterografts in children, J Thorac Cardiovasc SurgGeha A. S Laks H Stansel H. C 1979 78 351 64 - 14.
Early stenosis and calcification of glutaraldehyde-preserved porcine xenografts in children, Thorac Cardiovasc SurgHellberg K Ruschewski W De Vivie E. R 1981 29 369 74 - 15.
Porcine heterograft valve replacement in children, J Thorac Cardiovasc SurgWilliams D. B Danielson G. K Mcgoon D. C Puga F. J Mair D. D Edwards W. D 1982 84 446 50 - 16.
Surgical pathology of obstructed, right-sided, porcine-valved extracardiac conduits, Arch Pathol Lab MedEdwards W. D Agarwal K. C Feldt R. H Danielson G. K Puga F. J 1983 107 400 5 - 17.
Mayer JE Jr, Castaneda AR, Long-term follow-up of patients with synthetic right heart conduits, CirculationJonas R. A Freed M. D 1985 Suppl-III):II77 83 - 18.
Long-term results after right ventricular outflow tract reconstruction with porcine bioprosthetic conduits, J Card SurgKloevekorn W. P Meisner H Paek S. U Sebening F 1991 Suppl-IV):624 6 - 19.
The performance of Hancock porcine-valved Dacron conduit for right ventricular outflow tract reconstruction, Ann Thorac SurgBelli E Salihoglu E Leobon B Roubertie F Ly M Roussin R Serraf A 2010 89 152 7 - 20.
Calcification of aortic homografts used for reconstruction of the right ventricular outflow tract, J Thorac Cardiovasc SurgSaravalli O. A Somerville J Jefferson K. E 1980 80 909 20 - 21.
Experience with the extracardiac conduit, J Thorac Cardiovasc SurgCiaravella J. M Mcgoon D. C Danielson G. K Wallace R. B Mair D. D Ilstrup D. M 1979 78 920 30 - 22.
Growth and cell viability of aortic versus pulmonic homografts in the systemic circulation, CirculationAllen M. D Shoji Y Fujimura Y 1991 Suppl I):III94 9 - 23.
Mechanical durability of pulmonary allograft conduits at systemic pressure: angiographic and histological study in lambs, J Thorac Cardiovasc SurgKadoba K Armiger L. C Sawatari K Jonas R. A 1993 105 132 41 - 24.
EG, Gardner MAH, Pohlner PG, McGiffin DC, The viable cryopreserved allograft aortic valve, J Card SurgO Brien M. F Stafford 1987 153 67 - 25.
Prognostic importance of viability and a study of a second set allograft valve: an experimental study, J Card SurgYankah A. C Wottge H. U Muller-rucholz W 1988 3 263 70 - 26.
Pathology of explanted cryopreserved allograft heart valves: comparison with aortic valves from orthotopic heart transplants, J Thorac Cardiovasc SurgMitchell R. N Jonas R. A Schoen F. J 1998 115 118 27 - 27.
St Louis JD, Jaggers JJ, Ungerleider RM, Cryopreserved homografts in the pulmonary position: determinants of durability, Ann Thorac SurgForbess J. M Shah A. S 2001 71 54 60 - 28.
Late follow-up of 1095 patients undergoing operation for congenital heart disease utilizing pulmonary ventricle to pulmonary artery conduits, Ann Thorac SurgDearani J. A Danielson G. K Puga F. J Schaff H. V Warnes C. W Driscoll D. J 2003 75 399 411 - 29.
Reoperative homograft right ventricular outflow tract reconstruction, Ann Thorac SurgBielefeld M. R Bishop D. A Campbell D. N Mitchell M. B Grover F. L Clarke D. R 2001 71 482 8 - 30.
Homograt conduit failure in infants is not due to somatic outgrowth, J Thorac Cardiovasc SurgWells W. J Arroyo H Bremner R. M Wood J Starnes V. A 2002 124 88 96 - 31.
Right ventricular outflow tract reconstruction with an allograft conduit in non-Ross patients: risk factors for homograft dysfunction and failure, Ann Thorac SurgBrown J. W Ruzmetov M Rodefeld M. D Vijay P Turrentine M. W 2005 80 655 64 - 32.
Can you top this?, J Thorac Cardiovasc SurgCorno A. F 1998 116 670 1 - 33.
Long-term outcome of right ventricular outflow tract reconstruction with bicuspidalized homografts, Eur J Cardiothorac SurgBramer S Mokhles M. M Takkenberg J. J Bogers A. J 2011 40 1392 5 - 34.
Hetzer R Accelerated degeneration of allografts in the first two years of life, Ann Thorac SurgYankah A. C Alexi-meskhishvili V Weng Y Schorn K Lange P. E 1995 S71 7 - 35.
Evidence for rejection of homograft cardiac valves in infants, J Thorac Cardiovasc SurgRajani B Mee R. B Ratliff N. B 1998 115 111 7 - 36.
Performance of CryoValve SG decellularized pulmonary allografts compared with standard cryopreserved allografts, Ann Thorac SurgKonuma T Devaney E. J Bove E. L Gelehrter S Hirsch J. C Tavakkol Z Ohye R. G 2009 88 849 55 - 37.
Can pulmonary conduit dysfunction and failure be reduced in infants and children less than age 2 years at initial implantation? J Thorac Cardiovasc SurgKaramlou T Blackstone E. H Hawkins J. A Jacobs M. L Kanter K. R Brown J. W Mavroudis C Caldarone C. A Williams W. G Mccrindle B. W 2006 132 829 38 - 38.
Early results of valved bovine jugular vein conduit versus bicuspid homograft for right ventricular outflow tract reconstruction, Ann Thorac SurgBove T Demanet H Wauthy P Goldstein J. P Dessy H Viart P Deville A Deuvaert F. E 2002 74 536 41 - 39.
European Contegra multicentre study: 7-year results after 165 valved bovine jugular vein graft implantation, Thorac Cardiovasc SurgBreymann T Blanz U Woitalik M. A Daenen W Hetzer R Sarris G Stellin G Planché C Tsang V Weissmann N Boethig D 2009 57 257 69 - 40.
Valved bovine jugular vein conduits for right ventricular outflow tract reconstruction in children: an attractive alternative to pulmonary homograft, Ann Thorac SurgBrown J. W Ruzmetov M Rodefeld M. D Vijay P Darragh R. K 2006 82 909 16 - 41.
The bovine jugular vein: a totally integrated valved conduit to repair the right ventricular outflow, J Heart Valve DisCarrel T Berdat P Pavlovic M Pfammatter J. P 2002 11 552 6 - 42.
Bovine valved xenograft in pulmonary position: medium-term follow-up with excellent hemodynamics and freedom from calcifications, Ann Thorac SurgCorno A. F Qanadli S. D Sekarski N Artemisia S Hurni M Tozzi P Von Segesser L. K 2004 78 1382 8 - 43.
Jugular venous conduit (Contegra) matches allograft performance in infant truncus arteriosus repair, Eur J Cardiothorac SurgHickey E. D Mccrindle B. W Blackstone E. H Yeh T Pigula F Clarke D Tchervenkov C. I Hawkins J 2008 33 890 8 - 44.
MacArthur KJ, Pollock JC, Current status of the Contegra conduit for pediatric right ventricular outflow tract reconstruction, J Heart Valve DisRaja S. G Rasool F Yousuffudin S Danton M. D 2005 14 616 22 - 45.
Bovine jugular vein valved conduit: up to 10 years follow-up, J Thorac Cardiovasc SurgPrior N Alphonso N Arnold P Peart I Thorburn K Venugopal P Corno A. F 2011 141 983 746 - 46.
Pigula FA True aneurismal dilatation of a Contegra conduit after right ventricular outflow tract reconstruction: a novel mechanism of conduit failure, Ann Thorac SurgBautista-hernandez V Kaza A. K Benavidez O. J 2008 86 1976 7 - 47.
Mid term course after pediatric right ventricular outflow tract reconstruction: a comparison of homografts, porcine xenografts and Contegra, Eur J Cardiothorac SurgBoethig D Thies W. R Hecker H Breymann T 2005 27 58 66 - 48.
Aneurysm of the right ventricular outflow following bovine valved venous conduit insertion, Eur J Cardiothorac SurgBoudjemline Y Bonnet D Agnoletti G Vouhé P 2003 23 122 4 - 49.
Adverse mid-term outcome following RVOT reconstruction using the Contegra valved bovine jugular vein, Ann Thorac SurgGöber V Berdat P Pavlovic M Pfammatter J. P Carrel T. P 2005 79 625 31 - 50.
Formation of a stenotic fibrotic membrane at the distal anastomosis of bovine jugular vein grafts (Contegra) after right ventricular outflow tract reconstruction, J Thorac Cardiovasc SurgKadner A Dave H Stallmach T Turina M Pretre R 2004 127 285 6 - 51.
The Contegra conduit in the right ventricular outflow tract induces supravalvular stenosis, J Thorac Cardiovasc SurgMeyns B Van Garsse L Boshoff D Eyskens B Mertens L Gewillig M Fieuws S Verbeken E Daenen W 2004 128 834 40 - 52.
Encouraging results for the Contegra conduit in the problematic right ventricle-to-pulmonary artery connection, J Thorac Cardiovasc SurgMorales D. L Braud B. E Gunter K. S Carberry K. E Arrington K. A Heinle J. S Mckenzie E. D Fraser C. D 2006 132 665 71 - 53.
Bovine jugular vein conduit for right ventricular outflow tract reconstruction: evaluation of risk factors for mid-term outcome, Ann Thorac SurgRastan A. J Walther T Daehnert I Hambsch J Mohr F. W Janousek J Kostelka M 2006 82 1308 15 - 54.
Bu’lock FA, Barron DJ, Brawn WJ, Right ventricular outflow tract reconstruction using Contegra valved conduit: natural history and conduit performance under pressure, Eur J Cardiothorac SurgShebani S. O Mcguirk S Baghai M Stickley J De Giovanni J. V 2006 29 397 405 - 55.
Comparative computational fluid dynamic study of two distal Contegra conduit anastomoses, Int Cardiovasc Thorac SurgCorno A. F Mickaily-huber E. S 2008 7 1 5 - 56.
Tissue engineering of a pulmonary xenograft heart valve Asian Cardiovasc Thorac SurgDohmen P. M Ozaki S Verbeken E Yperman J Flameng W Konertz W 2002 10 25 30 - 57.
Hemodynamic characteristics of the Matrix P decellularized xenograft for pulmonary valve replacement during the Ross operation, J Heart Valve DisKonertz W Dohmen P. M Liu J 2005 14 78 81 - 58.
Evaluation of the decellularized pulmonary valve homograft (Synergraft), J Heart Valve DisBechtel M Muller-steinhardt M Schmidtke C Brunswik A Stierle U Sievers H. H 2003 12 734 40 - 59.
In vivo repopulation of xenogenic and allogenic acellular valve matrix conduits in the pulmonary circulation, Ann Thorac SurgLeyh R. G Wilhelmi M Rebe P Fischer S Kofidis T Haverich A Mertsching H 2003 75 1457 63 - 60.
Clinical performance of decellularized cryopreserved valved allografts compared with standard allografts in the right ventricular outflow tract Ann Thorac SurgBurch P. T Kaza A. K Lambert L. M Holubkov R Shaddy R. E Hawkins J. A 2010 90 1301 6 - 61.
Fortuna RS Decellularized versus standard cryopreserved valve allografts for right ventricular outflow tract reconstruction: a single-institution comparison. J Thorac Cardiovasc SurgRuzmetov M Shah J. J Geiss D. M 2012 143 543 9 - 62.
Valved bovine jugular vein conduits for right ventricular outflow tract reconstruction in children: an attractive alternative to pulmonary homograft Ann Thorac SurgBrown J. W Ruzmetov M Rodefeld M. D Vijay P Darragh R. K 2006 82 909 16 - 63.
Mid term course after pediatric right ventricular outflow tract reconstruction: a comparison of homografts, porcine xenografts and Contegra Eur J Cardiothorac SurgBoethig D Thies W. R Hecker H Breymann T 2005 27 58 66 - 64.
Shen I Oversizing pulmonary homograft conduits does not significantly decreases allograft failure in children Eur J Cardiothorac SurgKaramlou T Ungerleider R. M Alsoufi B Burch G Silberbach M Reller M 2005 27 548 53 - 65.
Pizarro C Outcomes following non-valved autologous reconstruction of the right ventricular outflow tract in neonates and infants Eur J Cardiothorac SurgDerby C. D Kolcz J Gidding S 2008 34 726 31 - 66.
Mori Y Repair of persistent truncus arteriosus without a conduit: sleeve resection of the pulmonary trunk from the aorta and direct right ventricle-pulmonary artery anastomosis Eur J Cardiothorac SurgNemoto S Ozawa H Sasaki T Katsumata T Kishi K Okumura K 2011 40 563 8 - 67.
Vouhé PR Common arterial trunk repair without extracardiac conduit: technically feasible potentially advantageous (Editorial comment) Eur J Cardiothorac Surg2011 40 569 70 - 68.
Tran Viet T, Duboys Y, Jarreau MM Reconstruction of the pulmonary outflow tract without prosthetic conduit J Thorac Cardiovasc SurgLecompte Y Neveux J. Y Leca F Zannini L 1982 84 727 33 - 69.
Danton MHD Barron DJ, Stumper O, Wright JG, DeGiovanni J, Silove ED, Brawn WJ Repair of truncus arteriosus: a considered approach to right ventricular outflow tract reconstruction Eur J Cardiothorac Surg2001 20 95 104 - 70.
Ben Ali W, Bajolle F, Marini D, Metton O, Bonnet D, Sidi D, Vouhé PR Common arterial trunk repair: with conduit or without? Eur J Cardiothorac SurgRaisky O 2009 36 675 82