Reoperation for obstructed pulmonary ventricle-pulmonary artery conduits

Common Arterial Trunk Repair by Means of a Handmade Bovine Pericardial-Valved Woven Dacron Conduit

BACKGROUND

Surgical repair of common arterial trunk (CAT) by means of a homograft conduit has become a standard practice. We report our experience in the correction of this heart disease with a handmade bovine pericardial-valved woven Dacron conduit as an alternative procedure to homografts, with a focus on early, mid-term, and long-term results.

METHODS

We designed a retrospective study that included 15 patients with a mean age of 1.5 years (range: three months to eight years), who underwent primary repair of simple CAT. Right ventricular outflow tract was reconstructed in all the cases with this handmade graft that was explanted at the time of its biological stenotic degeneration. A peeling procedure was performed at this time, in order to reconstruct the right ventricle-to-pulmonary artery continuity.

RESULTS

Overall mortality was 13.3% (one death at the early postoperative primary repair and the other at the mid-term postoperative peeling reoperation). Actuarial survival rate was 93.3%, 86.7%, and 86.7% at 5, 10, and 15 years, respectively. All of the 14 survivors developed stenosis of the handmade conduit at the mid-term period (8 ± 3 years), but after the peeling procedure, 13 survivors remain asymptomatic to date.

CONCLUSIONS

Primary repair of common arterial trunk using a handmade conduit can be performed with very low perioperative mortality and satisfactory mid-term and long-term results, which can be favorably compared with those reported with the use of homografts. When graft obstruction develops, peeling procedure is a good option because it does not affect the overall survival, although long-term outcomes warrant further follow-up.

Ventricular Outflow Tract Reconstruction with Polystan Valved Conduit

Experience with Polystan valved conduits in children with congenital heart disease was reviewed. From May 1997 to October 2000, 52 Polystan valved conduits were used for reconstruction of the pulmonary ventricular outflow tract in 50 patients. The median age was 24 months (range, 7 days to 19 years), body weight was 11 kg (range, 2.8 to 52 kg), and conduit size at operation was 19 mm (range, 12 to 24 mm). Early mortality was 12% (6/50). Late mortality was 6% (3/50). The median follow-up of survivors was 25 months (range, 2 to 43 months). Three patients underwent conduit replacement; 2 received larger conduits in a second-stage operation for ventricular septal defect closure. There was no death at reoperation. Polystan valved conduits can be used for reconstruction of the pulmonary ventricular outflow tract in congenital heart disease, with no significant conduit-related problems.

Direct complications of repeat median sternotomy in adults

Whilst the potential risk to underlying vital structures from redo-sternotomy is well recognized, the actual risk is poorly quantified. Our aim was to determine the incidence of complications directly attributable to redo-sternotomy and to ascertain whether the use of femoro-femoral CPB (FF) prior to redo-sternotomy alters operative morbidity and mortality. Case notes of 185 patients undergoing cardiac surgery necessitating redo-sternotomy between May 1998 and November 2002 were reviewed. Of 121 males and 64 females, the median age was 65.5 years (range 60.1-75 years). Elective FF was performed in 71 (38.3%) of cases and 114 (60%) were performed without the aid of prior femoro-femoral CPB (WFF). Three (1.6%) patients initially planned for WFF were converted to emergency FF due to serious complications. Complications directly attributable to redo-sternotomy occurred in 21 (11.3%) cases; 12 (16.9%) in the FF group and 9 (5.3%) in the WFF group. Overall mortality was 1.6%. In summary, our results suggest that morbidity risk for the operation increases significantly with redo-sternotomy alone. Three deaths in our series from direct complications attributable to redo-sternotomy signify an added risk. Hence the necessity for careful surgical technique and judicious use of elective FF-CPB is emphasized.

Right Ventricle to Pulmonary Artery Reconstruction Using a Valved Homograft

Although the valved homograft is widely used to establish a connection between the right ventricle (RV) and the pulmonary artery (PA), its durability remains controversial. In the present study, the data on 141 valved homograft implantations in 107 consecutive patients performed from January 1990 to June 2000 were analyzed. The mean follow-up period was 4.6 years (range, 0.2-9.4 years). The clinical data, including clinic records, operative notes, follow-up visits, and letters from referring physicians, were analyzed with particular reference to variables associated with early and late mortality, deterioration of the homograft, and risk factors for patient survival and homograft failure. Early death occurred in 7.5% (n=8) of the cases, and each of these patients died without leaving the hospital. Late death occurred in 2 patients, for whom the cause of death was suggested to be related to arrhythmia. Thirteen patients underwent catheter intervention (ie, balloon dilatation and/or stenting) and 8 of these did not require homograft replacement following catheterization. The overall survival rate at both 3 years and 5 years was 88.9+/-3.4%. Cumulative freedom from total homograft failure was 82.5+/-3.6% at 1 year; 61.6+/-5.0% at 3 years; and 42.4+/-6.2% at 5 years. In comparison with 2 criteria of homograft failure (ie, total homograft failure and homograft failure including catheter intervention), the incidence of freedom from homograft failure including catheter intervention was lower than that of total homograft failure, although the difference was not statistically significant. In the multivariate analysis, significant risk factors with respect to patient survival were homograft replacement and the use of expanded polytetrafluoroethylene (ePTFE); those judged to be significant with respect to homograft failure were total repair with first homograft implantation and diagnosis of truncus arteriosus. The valved homograft was thus considered an appropriate choice of conduit between the RV and the PA, and it provided excellent patient survival. However, this type of homograft did not provide a completely permanent solution for the repair of complex cardiac anomalies. Therefore, the use of ePTFE for homograft extensions should be avoided. Finally, the results suggest that catheter intervention plays an important role in the longevity of the implanted homograft.

Calcification of homograft valves in the pulmonary circulation -- is it device or donation related?

OBJECTIVE

Homograft valved conduits are used in the reconstruction of right ventricular outflow tract (RVOT), and calcification is a recognised phenomenon in these devices. The purpose of this study was to assess the effect of type (pulmonary and aortic) and mode of harvest of these cryopreserved homografts (cadaveric and beating heart) on the incidence of calcification of these conduits when used in the pulmonary circulation.

METHODS

A retrospective study was carried out on 60 patients with congenital heart defects who underwent reconstruction of RVOT using cryopreserved homograft valved conduits. The homografts were harvested from two different groups of donors; beating heart donors and cadaveric donors. The period of study was from 1st January 1990 to 31st December 2000. There were 34 males and 26 females, and the median age was 75 months. The 30-day mortality was 10 (16.7%). The 50 survivors were followed-up 3-108 months (median 36 months). Twenty-four had aortic homografts and 26 pulmonary homografts. Twenty-four devices were from cadaveric donors and 26 from beating heart donors.

RESULTS

There were 10 (20%) calcified devices, all aortic in origin. In a logistic regression analysis, aortic homografts were significant risk factor for calcification (P=0.0006). However, source of harvest was not significantly related to the incidence of calcification (P=0.6).

CONCLUSION

Cryopreserved pulmonary homografts placed in the right side of the heart are less likely to undergo calcification. Homografts harvested from beating heart donors do not appear to reduce the incidence of calcification.

Late results of repair of truncus arteriosus

Over the last three decades, management of truncus arteriosus has evolved with improving outcomes. Surgical repair is currently performed primarily during the neonatal period. This has prevented the severe morbidity and mortality resulting from congestive heart failure and pulmonary vascular obstructive disease. Although it has been 30 years since successful surgical repair of this lesion, the long-term follow-up studies have been limited to children who underwent truncus repair beyond the infancy period. In this article, we review the literature and also summarize the long-term results of truncus arteriosus at the University of California, San Francisco, where a repair in early infancy has been routine since 1975. A retrospective review was performed to assess long-term outcomes among 165 patients (81% of patients were < 1 year of age) who survived the initial hospital stay following complete repair of truncus arteriosus since 1975. There have been 23 late deaths, eight of which occurred within 6 months of repair and 13 of which occurred within 1 year. Ten of the late deaths were related to reoperations. The actuarial survival rate among all hospital survivors was 90% at 5 years, 85% at 10 years, and 83% at 15 years, and was essentially identical for infants alone. Significant independent risk factors for poorer long-term survival were truncus with moderate to severe truncal valve insufficiency before repair. During the follow-up period, 107 patients underwent 133 conduit reoperations at a median of 5.5 years after the initial repair. In addition, 26 patients underwent 30 truncal valve replacements. Actuarial freedom from truncal valve replacement was 63% at 10 years among patients with truncal insufficiency before initial repair. Ten- to 20-year survival and functional status were excellent among infants undergoing complete repair of the truncus arteriosus. Copyright 1998 by W.B. Saunders Company

Shelhigh No-React porcine pulmonic valve conduit: a new alternative to the homograft

BACKGROUND

The Shelhigh No-React pulmonic valve conduit is a new porcine conduit that is glutaraldehyde-treated and detoxified using a proprietary heparin process. In our institution it has been implanted in 25 patients. The aim of this present contribution is to evaluate the short-term follow-up after its implantation.

METHODS

From November 1997 to August 1999, 25 patients (mean age, 20.2 years; range, 0.6 to 28.3 years) were operated on using this conduit. Seventeen patients underwent a Ross procedure for aortic valve disease, with the conduits implanted in anatomic position; 6 patients underwent right ventricular outflow tract reconstruction; 2 patients underwent the Rastelli operation. The follow-up was complete. Preoperative and postoperative two-dimensional echocardiography data were collected.

RESULTS

There were two non-conduit-related deaths. Two conduits needed to be exchanged because of an increase in the gradient. Overall, all patients were improved in terms of New York Heart Association class. Comparison of preoperative and postoperative two-dimensional echocardiography gradient showed significant improvement. At the 30-month follow-up, no calcification was seen on the explanted conduits or on the two-dimensional echocardiography, although many of the patients are children.

CONCLUSIONS

The Shelhigh conduits seem to be an alternative to homograft especially in infants. These experiences are preliminary, and longer follow-up is required.

Direct neonatal ventriculo-arterial connections (REV): early results and future implications

BACKGROUND

Is the time-honored supposition correct that insertion of a competent prosthetic conduit or homograft is necessary to achieve right ventricular (RV) to pulmonary artery continuity in neonates? A direct ventriculo-arterial connection, or réparation à l'étage ventriculaire (REV), has been successfully used to achieve RV to pulmonary artery continuity in neonates without mortality or major morbidity. Acute RV function is preserved even in the face of free pulmonary insufficiency, but scrupulous preservation of pulmonary artery patency (unobstructed pathway) must be achieved.

METHODS

We retrospectively reviewed the cases of 6 neonates who underwent direct ventriculo-arterial connection to achieve RV to pulmonary artery continuity during open heart procedures in the last 3 years.

RESULTS

The 6 neonates had a mean age of 12.3 days (range, 2 days to 6 weeks) and a mean weight of 3.2 kg (range, 2.7 to 3.6 kg) at operation. Two of them had a diagnosis of aortic atresia + ventricular septal defect and successfully achieved an in-series circulation. Two had pulmonary atresia + ventricular septal defect and 2, double-outlet right ventricle + transposition of the great arteries + ventricular septal defect + pulmonary atresia. Follow-up is a mean of 16 months (range, 6 to 22 months). Surgical reintervention was required in 3 neonates and resulted in excellent hemodynamics in 2 of them. In the other patient, who had bilateral long-segment branch pulmonary artery hypoplasia, stents were placed without hemodynamic benefit. All children are currently alive with preserved RV function even in the presence of free pulmonary insufficiency.

CONCLUSIONS

Although the creation of a direct ventriculo-arterial connection has routinely been used for children older than 1 year with satisfactory initial results, its application in neonate is very limited. Why have neonates been denied this viable alternative? Perhaps the answer involves legitimate concerns about the consequent free pulmonary insufficiency and the presumed acute RV diastolic dysfunction.

Intermediate follow-up of right ventricular outflow tract reconstruction with allograft conduits

BACKGROUND

Allograft conduits are among many varieties of material used for right ventricular outflow tract reconstruction. They invariably need to be replaced due to growth of the patient or conduit failure.

METHODS

From June 1984 to June 1996, a total of 76 patients underwent reconstruction of the right ventricular outflow tract with an allograft conduit: 51 aortic and 25 pulmonary. The median age, weight and conduit size at surgery were 37 months (range, 0.2 to 228 months), 12.4 kg (range, 2.9 to 61.4 kg), and 17 mm (range, 8 to 26 mm), respectively.

RESULTS

The hospital mortality was 5.3% (4 of 76 patients) and 2 patients died at 9 and 78 months follow-up. The median follow-up was 61 months (range, 2 to 132 months). Reoperation was necessary in 22 patients (28.9%) at a median interval of 50.5 months (range, 3 to 109 months) and the median conduit size was 21 mm (range, 12 to 23 months). There was no mortality. Freedom from reoperation at 64 months was 49.5% for conduits 15 mm and smaller, and 73.3% for conduits 16 mm and larger. Analysis by age shows freedom from reoperation at 64 months of 49.4% and 74.5% for patients younger than and older than 2 years, respectively. At 54 months there was no statistical difference in freedom from reoperation between pulmonary and aortic allografts.

CONCLUSION

Right ventricular outflow tract reconstruction with allograft conduits results in a high reoperation rate at 4 years but provides significantly longer freedom from reoperation with conduits larger than 15 mm or in patients over 24 months of age.

Pulmonary root replacement with the Freestyle stentless aortic xenograft in growing pigs

BACKGROUND

The stentless xenograft with its favorable hemodynamic performance on the left side of the heart seems an attractive, readily available alternative for the reconstruction of the right ventricular outflow tract in children.

METHODS

To assess its function in a preclinical animal investigation, we replaced the pulmonary root with a Freestyle stentless aortic xenograft in 18 piglets of 26.6 +/- 3.2 kg weight. The animals were allowed to grow as much as possible and slaughtered when symptoms of heart failure developed or body weight reached more than 160 kg. All valve explants were analyzed by gross examination and photography and, in 4 representative pigs, by histologic examination.

RESULTS

Fourteen animals died prematurely after 2 weeks to 11 months. Twelve xenograft explants showed thick, immobilized, large nodular structures as cuspal remnants causing significant stenosis. At microscopy, large cuspal masses of degenerating collagen and fibrin and various inflammatory cells were frequently found. In the growing pig, most of the xenografts implanted in the pulmonary position showed early degeneration causing severe stenosis.

CONCLUSIONS

Use of this valve for right ventricular outflow tract reconstruction in children cannot be recommended.

Ascending aortic extension for right pulmonary artery stenosis associated with ventricular-to-pulmonary artery conduit replacement

BACKGROUND

Ventricular-to-pulmonary artery conduits in growing patients with congenital heart disease will require replacement from time to time due to somatic growth, neointimal hyperplasia, and pulmonary artery stenosis. The purpose of this article is to review our experience with ascending aortic extension for significant long-segment pulmonary artery stenosis in patients undergoing reoperation for right ventricular-to-pulmonary artery conduit replacement.

METHODS

From 1989 to 1997, 8 patients had aortic transection, right pulmonary artery augmentation arterioplasty, and aortic interposition graft (Hemashield in 7 and Gore-tex in 1) in association with right ventricular-to-pulmonary artery conduit replacement in 7 patients and completion Fontan operation in 1 patient. Aortic cross-clamp time was 90 +/- 34 minutes, and the cardiopulmonary bypass time was 205 +/- 37 minutes.

RESULTS

All patients survived. In those 7 patients who had conduit replacement, the RV/LV ratio declined from 0.78 +/- 0.15 to 0.45 +/- 0.05 postoperatively (P < 0.05). Average length of stay was 8.9 +/- 7.2 days. Follow-up range is 18 months to 8 years (mean 4 years). Two complications included cardiac transplantation for pre-existing poor left ventricular function and accelerated conduit stenosis leading to conduit re-replacement.

CONCLUSION

Ascending aortic extension facilitates long-segment pulmonary artery augmentation arterioplasty and enlarges the retroaortic space, preventing future compression restenosis.

Use of a bovine jugular vein graft with natural valve for right ventricular outflow tract reconstruction: a one-year animal study

OBJECTIVE

We evaluated a bovine jugular vein graft with a natural trileaflet valve for right ventricular outflow tract reconstruction in a canine study for an entire year.

METHODS

Heparinized bovine jugular vein grafts with a natural valve cross-linked with a hydrophilic polyepoxy compound of 18 to 20 mm in internal diameter were implanted in the right ventricular-pulmonary arterial position in eight dogs, and the main natural pulmonary artery was ligated. Anticoagulants were not used after implantation. Five grafts were retrieved on day 182 after implantation and the other three grafts on days 196, 375, and 385, respectively, and were inspected by macroscopic and microscopic observation. Cardiac catheterization, followed by angiography and echocardiography, was done just before graft retrieval.

RESULTS

No graft kinking or regurgitation of the valve was observed. Echocardiography showed natural valve motion without thickening of the leaflets. Blood pressure in the conduits ranged from 18/9 to 31/4 mm Hg, in the right ventricle from 18/4 to 40/0 mm Hg, and the gradient varied from 0 to 14 mm Hg. The explanted conduits maintained their original shape, softness, and pliability with good coaptation of valves, without calcification or degenerative changes, except for one leaflet with slight deformation. In microscopic observation, endothelial cells lined the luminal surface of the conduit except for the areas adjacent to the valve.

CONCLUSION

The graft worked perfectly as a right ventricular-pulmonary arterial valved conduit without anticoagulant therapy for a long time.

Long-term follow-up of truncus arteriosus repaired in infancy: a twenty-year experience

BACKGROUND

There have been few reports of long-term follow-up after truncus arteriosus repair in infancy.

METHODS

A retrospective review was performed to assess long-term outcomes among 165 patients who survived the initial hospital stay after complete repair of truncus arteriosus since 1975. The median age at truncus repair over this 20-year experience was 3.5 months (range 2 days to 36 years), and 81% of patients were less than 1 year of age. Previous pulmonary artery banding had been performed in 15 patients, and two patients had undergone prior repair of interrupted aortic arch. Significant procedures performed along with truncus repair included truncal valve replacement (n = 10) or repair (n = 5) and repair of interrupted aortic arch (n = 4).

RESULTS

Patients were followed up for up to 20.4 years (median 10.5 years). Twenty-five patients were lost at cross-sectional follow-up, with a total of 67 patient-years of follow-up available on these patients. There have been 23 late deaths, eight of which occurred within 6 months of repair and 13 of which occurred within 1 year. Ten of the late deaths were related to reoperations. Actuarial survival among all hospital survivors was 90% at 5 years, 85% at 10 years, and 83% at 15 years and was essentially identical for infants alone. A significant independent risk factor for poorer long-term survival was truncus with moderate to severe truncal valve insufficiency before repair. During the follow-up period, 107 patients underwent 133 conduit reoperations. Median time to conduit reoperation was 5.5 years, and the only factor significantly associated with shorter time to conduit replacement was smaller conduit size at initial repair. In addition, 26 patients underwent 30 truncal valve replacements. Six patients required truncal valve replacement before any conduit-related reintervention, with two associated deaths. Actuarial freedom from truncal valve replacement among patients with no prerepair truncal valve insufficiency was 95% at 10 years. Actuarial freedom from truncal valve replacement was significantly lower among patients with truncal insufficiency before initial repair (63% at 10 years). At follow-up, all patients except three were in New York Heart Association functional class I.

CONCLUSIONS

Ten- to 20-year survival and functional status are excellent among infants undergoing complete repair of truncus arteriosus. Conduit replacement or revision is almost inevitably necessary in this group of patients.

Autologous glutaraldehyde-treated pericardial valved conduit: an experimental study

Extracardiac conduits in the form of allografts and synthetic tubes containing heterograft valves have been used widely in the management of ventricular outflow abnormalities and for establishing ventriculoarterial continuity. These procedures are limited by long-term calcification as well as by formation of neointimal peel, necessitating reoperation. In an effort to continue the search for an alternative conduit, we designed and evaluated a valved sinus-bearing conduit fashioned out of autologous pericardium treated with glutaraldehyde. The construction of the conduit is described. The results of implantation of these conduits in 12 sheep showed no progression of gradients, fresh regurgitation, or evidence of wall or cusp calcification 9 months after implantation.

Outcome of pulmonary and aortic homografts for right ventricular outflow tract reconstruction

To determine late patient outcome and homograft durability, we reviewed 326 patients who received aortic (n = 230) or pulmonary (n = 118) cryopreserved homografts for right ventricular outflow reconstruction between January 1985 and October 1993. Patient survival, including operative mortality, 5 years after the operation was similar between the two groups (pulmonary homograft 86%, aortic homograft 80%; p = not significant by log-rank test). However, 5-year freedom from homograft failure was significantly better for pulmonary homografts (94% versus 70%, p < 0.01 by log-rank test). Late calcification was evaluated by chest roentgenography and echocardiography. Overall, 20% of aortic homografts became moderately or severely calcified compared with 4% of pulmonary homografts (p < 0.01). Twenty-six percent of aortic homografts in children 4 years old or younger had moderate or severe obstruction associated with calcification, whereas only 11% of aortic homografts in patients over 4 years of age had calcific obstruction (p < 0.01). No late deaths among patients receiving pulmonary homografts were related to graft failure; two late deaths in the aortic homograft group were homograft related. Risk factors for patient mortality and homograft failure (defined as either need for homograft replacement because of homograft failure or as homograft-related death) were identified by the Cox multivariate analysis. Aortic type of homograft was a significant risk factor for homograft failure (p < 0.0001), but type of homograft was not correlated with patient mortality. Age 4 years or younger was a significant risk factor for both mortality (p < 0.01) and homograft failure (p = 0.03) in aortic homograft recipients but not in pulmonary homograft recipients. These results indicate that both aortic and pulmonary homografts provided excellent intermediate-term patient survival after right ventricular outflow tract reconstruction, but pulmonary homografts are more durable than aortic homografts with less calcification and obstruction, especially among children 4 years old or younger.

Failure of the Hemashield extension in right ventricle-to-pulmonary artery conduits

Between 1989 and 1991, 17 children underwent 18 right ventricle-to-pulmonary artery conduit placement operations using a composite of an aortic or pulmonary valved homograft and a Hemashield extension to the ventricle. Hemashield is a collagen-coated knitted Dacron graft with excellent compliance and hemostatic properties. Diagnoses included tetralogy of Fallot with pulmonary atresia (7), truncus arteriosus (6), and complex transposition of the great arteries (4). Mean age at conduit placement was 4.9 +/- 4.2 years, and all patients survived. At a mean follow-up of 14 +/- 4 months, postoperative Doppler echocardiographic gradients between the ventricle and pulmonary artery ranged from less than 20 to 60 mm Hg. At cardiac catheterization 13 +/- 3 months postoperatively (6 patients), the systolic pressure gradient across the conduits ranged from 14 to 90 mm Hg (mean gradient, 59 +/- 29 mm Hg). Conduit obstruction, when present, was demonstrated angiographically to be in the Hemashield portion and led to early conduit replacement six times in 5 patients (33% of operations) within 10 to 18 months (mean time, 14 months) after insertion of the original conduit. Pathologic examination of the explanted conduits revealed the obstruction to be a thick neointimal peel that was impossible to separate from the Hemashield graft. Failure of the Hemashield as an extension for ventricle-to-pulmonary artery conduits secondary to accelerated neointimal formation has led us to abandon its use in clinical practice.

Radionuclide assessment of left ventricular performance on exercise after external conduit operation

Only limited information is available concerning left ventricular (LV) response to exercise after an external conduit operation for cyanotic congenital heart disease. Sixteen patients who had undergone external conduit repair (EC group) were studied with multi-gated cardiac pool imaging using a supine bicycle ergometer on 20 occasions. Six patients with a history of Kawasaki disease without coronary artery stenosis served as controls (control group). Myocardial imaging and cardiac catheterization were also performed in the EC group. There was no significant difference in left ventricular ejection fraction (LVEF) at rest between the groups. However, on exercise, LVEF of the EC group was significantly lower than that of the control group. Nine patients in the EC group showed a perfusion defect (PD) on 12 occasions. LVEF on exercise of the patients with PD was significantly lower than that of the patients without PD. Furthermore, only the patients with PD showed a LVEF decrease of 5% or more in response to exercise. In the EC group, a significant inverse relationship was demonstrated between right ventricular systolic pressure (RVP) and LVEF response to exercise. However, two out of four patients who underwent external conduit replacement improved their LVEF response to exercise with successful reduction of RVP. These findings indicate that an impaired left ventricular response to exercise was common in patients after external conduit operations. Myocardial damage and right ventricular outflow tract obstruction could be the causes of this left ventricular dysfunction.

Clinical results of cryopreserved valved conduits in the pulmonary ventricle-to-pulmonary artery position

Aortic valved homograft conduits (AVHC) have become valuable in the pulmonary ventricle (PV)-to-main pulmonary artery (MPA) reconstruction in congenital heart defects. Since 1985, 45 patients, ranging in age from 12 days to 32 years, underwent PV-to-MPA reconstruction utilizing cryopreserved AVHC. Operative deaths included seven patients (16%), six of whom died as a result of the complexity of their underlying heart defects. One late death (2%) occurred as a result of infective endocarditis 48 months after conduit placement. The 38 patients who survived the operation remained in the intensive care unit for a mean of 5.7 +/- 1.0 days (median: 4 days; range: 2 to 37 days). The mean hospital stay was 13.0 +/- 1.8 days (median: 9 days; range: 6 to 63 days). The mean follow-up was 40.0 +/- 3.6 months (median: 40 months; range: 10 months to 7.1 years). Only two patients (5%) required reoperation for conduit stenosis with systolic pressure gradients of 60 to 80 mm Hg at 10 and 14 months, respectively, after operation, and both reoperations were successful. During outpatient visits, 16 patients are totally asymptomatic, and 21 patients have minimal symptoms (New York Heart Association class II). Only 10 patients (26%) require digoxin, and 2 patients (5%) need diuretics as part of their medical regimen. Recent echocardiographic examinations show insignificant pressure gradients in all 37 currently surviving patients. Thus, barring operative mortality, which is almost always associated with the nature of the underlying heart defect, the use of cryopreserved AVHC is a safe and effective alternative for PV-to-MPA reconstruction.

Repair of conotruncal abnormalities with the use of the valved conduit: improved early and midterm results with the cryopreserved homograft

Repair of complex cardiac lesions has been facilitated by the availability of valved conduits to reestablish right ventricular to pulmonary artery continuity. From 1977 to June 1991, 148 patients underwent repair with insertion of a conduit. Their mean age was 6.6 years (11 days to 45 years). The diagnosis was transposition of the great arteries with ventricular septal defect and left ventricular outflow tract obstruction in 51, truncus arteriosus in 36, pulmonary atresia with ventricular septal defect in 25, tetralogy of Fallot in 19, double-outlet right ventricle in 10, pulmonary atresia with intact ventricular septum in 6 and atrioventricular canal with pulmonary atresia in 1. A Dacron porcine-valved conduit was used in 37, a homograft conduit in 106 and a nonvalved conduit in 5. There were 13 early deaths overall (8.8%); 8 (22%) of the early deaths occurred in the 37 patients who received a Dacron graft, 4 (3.8%) occurred in the 106 patients who received a homograft and 1 occurred in a patient with a nonvalved Gore-Tex conduit. An additional patient underwent orthotopic heart transplantation in the early postoperative period. In 117 patients operated on from January 1985 to June 1991 the early mortality rate was 2.6% (3 of 117). Among 28 patients receiving a Dacron porcine-valved graft there were two late deaths (7.1%) after a mean follow-up interval of 93 months, and 8 patients required reoperation for conduit obstruction. Among 102 homograft recipients there were two late deaths (1.9%).(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term results after right ventricular outflow tract reconstruction with porcine bioprosthetic conduits

From 1975 to 1990, a total of 110 patients were operated for complex cardiac malformations with impaired pulmonary artery perfusion using porcine valved right heart to pulmonary artery conduits. Twelve- to 30-mm porcine valved conduits (Hancock or Carpentier-Edwards) were implanted at the age of 4 weeks to 28 years (mean 4.3 years). The patients' body weights were 2.9-68 kg (mean 15.3 kg). Early mortality was 5.5% (six patients), late mortality was 12.7% (14 patients), and 90 patients could be included in this long-term follow-up (426 patient-years). So far, 41 of the conduits had to be exchanged 4 months to 15 years (mean 6.5 years) after the first implantation. Forty-nine of the conduits are still in place. At reoperation, 38 patients received an allograft; three patients, reoperated before 1982, had a second xenograft. The main reason for porcine conduit malfunction was degeneration and/or calcification of the valves. In 11 patients, however, with 12- and 14-mm conduits implanted at a mean age of 3.1 years, a reoperation was necessary after a mean time of 6.8 years because these children had "outgrown" the conduit and needed a bigger one. We conclude that even though allografts seem to be the conduit of choice for right ventricular outflow tract reconstruction, our clinical experience shows that porcine valved conduits can be used just as well since most of them function sufficiently well for as long as 5 to 10 years, and early valve failure is relatively rare.

Resternotomy in patients with valved conduits adherent to the sternum

Twenty-two patients with valved conduits adherent to the sternum underwent resternotomy. Mean age was 10 +/- 6 years, and mean conduit age was 4 +/- 4 years. Diagnoses were D-transposition (7), truncus arteriosus (7), univentricular heart (6), Taussig-Bing anomaly (1), and corrected transposition (1). The majority of patients (68%) had reoperation for outgrown or degenerated conduits. In 17 patients, the sternum was opened with a chisel. Two of these patients sustained conduit neointimal collapse from manipulation, and 3 had conduit tear requiring immediate cardiopulmonary bypass through the femoral vessels. In the last 5 patients, the sternum was opened above and below the conduit, and the inner table was chiseled and left attached to the conduit avoiding injury and undue conduit manipulation. Cardiopulmonary bypass and operation were carried out uneventfully. We believe that the recent technique described provides a safe alternative approach to valved conduits adherent to the sternum.

Extracardiac valved conduits in the pulmonary circuit

Extracardiac valved conduits represent one of the weakest facets of reconstructive surgery for congenital heart disease in that they invariably need to be replaced because of growth of the patient or because of valve or conduit failure. Between 1979 and 1989, 141 patients had 169 valved conduits placed between the heart and the pulmonary artery circuit. There were 81 male and 60 female patients, aged 2 days to 35 years (mean age, 5.9 years), with 46 patients less than 1 year of age. We performed primary repair in 117 patients; in this group, there have been 28 conduit replacements in 27 patients. In 17 patients initial repair with a conduit was performed elsewhere and we replaced these conduits in 15 and removed them in 2. A further group of 9 patients were seen after repair of tetralogy of Fallot or double-outlet right ventricle, with severe pulmonary incompetence or right ventricular outflow tract aneurysm. All had valved conduits inserted as secondary procedures. The types of valved conduits used were xenograft (n = 126) and homograft (n = 43). There were six hospital deaths (3.6%; 70% confidence limits [CL], 2% to 6%) and seven late deaths (4.1%; CL, 2.5% to 6.5%) in a total of 169 conduit insertions. Forty-five conduits have been removed and 43 reinserted without early or late mortality (0%; CL, 0% to 4%). Actuarial survival after conduit insertion was 87% at 5 years (CL, 80% to 92%), including operative mortality. Actuarial freedom from conduit replacement was 37% at 5 years (CL, 20% to 56%). Conduit insertion in infants and small children ensures subsequent replacement, but this can be done at low risk.(ABSTRACT TRUNCATED AT 250 WORDS)

Hand-made valved conduit with high-porosity knitted graft and glutaraldehyde-treated autologous pericardial trileaflet valve

In 10 patients with various congenital heart defects requiring reconstruction of right ventricle to pulmonary artery continuity, a new hand-made valved conduit was introduced. To avoid late stenosis with peel formation of the graft, high-porosity Golaski knitted graft was chosen. The graft was sealed by fibrin glue, and autologous pericardium was treated with glutaraldehyde and used to construct a trileaflet valve inside the graft. This hand-made graft was pliable with good conformability. The valve function was found good in the intermediate follow-up in 8 patients. This composite valved conduit may be a good alternative to the xenograft valved conduit when allograft conduit is not available.

Pathological findings of the aortic homograft in a patient with tetralogy of Fallot twenty years after implantation

We report pathological findings of the aortic homograft in a 27-year-old patient who died 20 years after implantation at the time of correction of tetralogy of Fallot. Although calcification of the homograft was severe with degeneration of valve leaflets, no functional obstruction of the homograft was found as a conduit. This observation may suggest a beneficial aspect of the aortic homograft as the right ventricle to the pulmonary artery conduit late after corrective surgery even if calcification was not avoided.

Doppler evaluation of homograft valved conduits in children

To assess the flow characteristics of homograft valved conduits in the immediate postoperative period, 69 children with 71 homograft conduits underwent 2-dimensional and Doppler echocardiographic examination at 1 to 40 days (mean 8) after surgery. Of the 71 conduits studied, 19 were aortic and 52 were pulmonary homograft valved conduits. Two aortic homograft valved conduits were inserted in the aortic position, whereas all remaining homografts were placed in the pulmonary position. On the immediate postoperative echocardiogram, 25 (35%) of the conduit valves had no regurgitation and 44 (62%) had 1+ (mild) regurgitation. Two pulmonary valved conduits (3%) in the pulmonary position had 2+ (moderate) regurgitation and right ventricular dimensions greater than 95% for body surface area. The peak velocity across the homograft valve was normal (less than 1.3 m/s) in 58 valves (82%). In the remaining 13 valves, peak velocity ranged from 1.4 to 2.6 m/s. No homograft valve had a peak velocity greater than 2.6 m/s in the immediate postoperative period. To assess the fate of homograft valved conduits in the intermediate-term follow-up period, 38 children with 38 conduits had a repeat echocardiogram at 6 to 25 months (mean 15 +/- 6) after surgery. Of the 38 conduits examined, 10 (26%) had no regurgitation, 25 (66%) had 1+ regurgitation and 3 (8%) had 2+ regurgitation. Progression of the amount of regurgitation occurred in 11 (29%) patients. At the follow-up examination, peak velocity was less than or equal to 1.4 m/s across 34 conduit valves, between 1.4 and 2.6 m/s across 3 valves and greater than 2.6 m/s across 1 valve.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic allografts: reconstruction of right ventricle-pulmonary artery continuity

The use of aortic allografts in the repair of congenital cardiac lesions has increased as a result of both the advent of cryopreservation and the effects of increased donor availability secondary to infant transplantation. During the period 1986 through 1987, 38 cryopreserved aortic allografts were placed for right ventricle-pulmonary artery discontinuity. Size of the allografts ranged from 11 to 26 mm (mean size, 19 mm), and age of the patients ranged from 6 weeks to 26 years (mean age, 5 years). Twenty-one patients had primary placement of aortic allografts, and 17 underwent replacement of previous conduits. There were 5 hospital deaths (13%) overall, only 1 among the 10 patients younger than 6 months of age with truncus arteriosus, and none among the 17 patients having conduit replacement. A large conduit could be placed with a low incidence (10.5%) of postoperative hemorrhage related to the conduit. The aortic allograft is our conduit of choice for both conduit replacement and primary repair of right ventricle-pulmonary artery discontinuity.

A new physiologic correction technique for re-establishment of pulmonary circulation. Experimental surgical development

A new physiologic technique is presented for surgical correction of truncus arteriosus, pseudotruncus, transposition of the great arteries, double right ventricular outflow tract with subpulmonary ventricular septal defect and certain cases of Fallot's tetralogy. The basis of the technique are creation of a neo-right atrium, neo-pulmonary trunk, neo-right atrioventricular valve and a neo-pulmonary valve by right angular atriotomy and insertion of a homologous pericardial patch with a monocuspid valve. The pulmonary circulation is re-established by anastomosis of the neo-pulmonary trunk to the pulmonary tree. The technique was used on 26 mongrel dogs. In 14 the experiments were preliminary, to evaluate the technique's validity, and in the other 12 it was performed with extracorporeal circulation and the hemodynamic status was studied at 30 and 180 min postoperatively. The technique and its results and potential advantages are described. Clinical application is considered to be feasible.

Long-term results after extracardiac valved conduits implanted for complex congenital heart disease

Between August 1982 and December 1986, 56 patients survived implantation of an extracardiac valved conduit for complex congenital heart disease. The mean age at operation was 4.2 years (16 days to 24 yrs) and the mean weight was 15.9 kg (2.4 to 93.0 kg). The diagnosis was pulmonary atresia (PA) with ventricular septal defect (VSD) in 13 patients, tetralogy of Fallot in 11, transposition of the great arteries (TGA) with VSD in 8, truncus arteriosus, in 7, complex left ventricular outflow tract obstruction (LVOTO) in 6, complex left atrioventricular valve obstruction in 4, double outlet right ventricle with VSD and subaortic obstruction in 3, univentricular heart with pulmonary stenosis in 2, TGA with LVOTO in 1, and PA with intact ventricular septum in 1. In 35 patients, a preclotted conventional Dacron conduit (CDC) with bioprosthetic valve was used, in 19 patients a collagen-sealed Tascon valved conduit (TC) was implanted, and in 1 patient an aortic homograft was used. In a mean follow-up of 32.5 months (9 to 64 mo), there were two deaths (2/56, 3.6%) that were not related to the conduit. All survivors have been evaluated by two-dimensional and Doppler echocardiography, and 29/56 (51.8%) underwent cardiac catheterization. Nine patients (9/56, 16.1%) underwent successful valved conduit replacement, in seven cases with a nonvalved conduit. There was a significant difference (P = .011) with regard to the incidence of conduit replacement between the group with CDC (2/36, 5.5%) and the group with TC (7/19, 36.8%). Five patients underwent percutaneous transluminal balloon dilatation of the prosthetic conduit, with adequate relief of the gradient in four patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Porcine-valved Dacron conduits in Fontan procedures

From a series of 52 Fontan procedures between 1976 and 1984, 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 11 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 71% at 10 years. In conclusion, we believe that the porcine-valved conduits have functioned very satisfactorily over time.

Traumatic rupture of extracardiac valved conduit: unusual late complication producing outflow tract obstruction

A 22-year-old woman died suddenly 15 years after successful repair of truncus arteriosus with a valved Dacron conduit. At autopsy there was complete obstruction of the right ventricular outflow tract by a large organizing thrombus between the outer aspect of the conduit and the adherent pericardial tissue. This rare late complication may have resulted from an unrecognized deceleration injury occurring at the time of a serious automobile accident 5 months before death.

The long-term success of skeletal muscle in aortic repair

To determine the efficacy of skeletal muscle for aortic repair, 23 swine underwent repair of descending thoracic aortic defects. In one group, a vascularized muscle flap was used to patch a 2- to 3-cm aortic defect. In two other groups, a short segment of aorta was removed and a 2-cm tube graft of freshly harvested but devascularized skeletal muscle or Vicryl mesh was used to repair the aorta. Swine were followed for up to sixteen months after implantation. There were no deaths or graft-related complications in the vascularized muscle patch group, and after sixteen months, there were no stenoses or aneurysmal dilatations of the flaps. Histologically, a mature pseudointimal layer had been deposited under the muscle flap and was grossly indistinguishable from normal arterial wall. In the group that received devascularized muscle tube grafts, however, suture line dehiscences occurred in 3 of 7 animals within two weeks of operation. There were no dehiscences in the 9 recipients of a Vicryl tube graft, a finding suggesting that deposition of pseudointimal elements was rapid enough to ensure vascular integrity as the Vicryl was absorbed. Postmortem examination of these animals demonstrated stenoses ranging from 30 to 50%, thereby indicating a lack of growth in the new pseudointimal wall. These results demonstrate the long-term reliability of vascularized skeletal muscle for use in major vascular reconstruction, and suggest the beneficial effects of avoiding prosthetic material and promoting optimal pseudointimal formation.

Intermediate-term fate of cryopreserved allograft and xenograft valved conduits

Actuarial freedom from reoperation for obstruction in 147 patients receiving cryopreserved or fresh allograft valved conduits between a ventricle and the pulmonary arteries was 94% at 3.5 years. The 2 patients undergoing reoperation were 6 and 36 months of age at the time of insertion of the allograft. Among 24 patients in whom cardiac catheterization was performed on indication late postoperatively, 5 had gradients of more than 40 mm Hg across the conduit. For comparison, among 78 patients receiving xenograft or irradiated allograft valved conduits, the percentages of freedom from conduit reoperation at 3.5, 5, 10, and 15 years were 99%, 95%, 59%, and 11%, respectively. The diameters of the allograft and xenograft valves inserted varied directly with the age and size of the patients, but in patients 3 to 5 years of age, allografts with a diameter of at least 21 mm could usually be used.

Right and left ventricular volume characteristics after external conduit repair (Rastelli procedure) for cyanotic congenital heart disease

We studied right and left ventricular (RV and LV) volume characteristics in 18 patients who had undergone an external conduit repair (Rastelli procedure) at 3-17 years of age (mean 7.5 years). Cardiac output, measured by means of a thermodilution method, was 3.8 +/- 0.8 1/min/m2 (mean +/- SD). Peak RV pressure was 104 +/- 28 mmHg in six patients who had been operated on 6 years or more before this study, significantly higher than in patients with a shorter follow-up period (72 +/- 19 mmHg for 1-5 years follow-up in six patients and 54 +/- 10 mmHg at 1 month after operation in six patients). RV end-diastolic volume (EDV) was 113% +/- 40% of normal, and RV ejection fraction (EF) was 0.52 +/- 0.10, lower than normal. RVEDV was inversely correlated with peak RV pressure (r = -0.78). This parameter was 0.42 +/- 0.06 in the six patients with the longest follow-up period, lower than in the other two groups (0.52 +/- 0.08 in 1-5 years follow-up, 0.60 +/- 0.03 at 1 month after surgery). LVEF was 151% +/- 38% of normal. LVEF was lower than normal in 6 of 12 patients who underwent surgery at the age of 6 years or more and in none of the six younger patients. The data indicate that in these patients, RVEF decreases with the increase of peak RV pressure and the increase in time since operation, especially 6 years or more after surgery. LV pump function is also depressed, possibly partly because of longstanding pre-operative hypoxemia.

Fifteen years' experience with the aortic homograft: the conduit of choice for right ventricular outflow tract reconstruction

Ninety-seven patients with pulmonary atresia underwent right ventricular outflow tract reconstruction using a homograft conduit. There were 46 hospital deaths (47%). Hospital mortality was significantly related to irreversible pulmonary hypertension (p less than 0.001) and thoracotomy for ligation of bronchial collaterals (p less than 0.01). The actuarial survival was 37 +/- 7% at 10 years. Sixteen patients undergoing recatheterization at a mean of 6 years had a mean transconduit gradient of 24 +/- 15 mm Hg. Obstructed conduits (i.e., with a gradient of greater than 50 mm Hg) were replaced in 3 patients, corresponding to 13 +/- 8% at 10 years. In each instance, the obstruction was due to neointimal hyperplasia in the Dacron tube rather than calcification of the homograft valve. The fresh, antibiotic-sterilized aortic homograft is the conduit of choice for right ventricular outflow tract reconstruction. The valve itself appears more resistant to calcification than its xenograft counterpart, and the absence of Dacron removes the problem of fibrinous peel obstructing the conduit. We now construct a tube of autologous pericardium to increase the length of the conduit and avoid complementary thoracotomy for ligation of bronchial collaterals.