Aortic allografts and pulmonary autografts for replacement of the aortic valve and aortic root

BACKGROUND

Extensive experience has accumulated with the use of aortic and pulmonary autografts for replacement of the aortic valve and the aortic root. Three general techniques for insertion have been used: subcoronary (free-hand) valve implantation, mini- or inclusion-root implantation, and aortic root replacement. Thirty-day mortality for elective operations with all of these techniques has not exceeded 5%. Thromboembolic episodes have been rare, and endocarditis has occurred infrequently. Early hemodynamic performance has been excellent, without significant gradients or valve regurgitation in the majority of patients.

METHODS AND RESULTS

Progressive aortic regurgitation has been observed with continued follow-up, and is the most important complication of both types of valves. Leaflet failure and technical problems are the major causes of reoperation for patients receiving aortic allografts. There is some evidence to suggest that the prevalence of these complications is lower with the root replacement technique than with the intraaortic implantation methods.

CONCLUSIONS

Reoperation for regurgitation of the neoaortic valve is the major complication of the pulmonary autograft procedure. The incidence of reoperation appears to be lowest with the root replacement technique. Certain conditions (acute rheumatic fever, juvenile rheumatoid arthritis, systemic lupus, ankylosing spondylitis, Libman-Sachs endocarditis, and possibly a dilated aortic root) may be contraindications to the use of a pulmonary autograft. Reoperation on the pulmonary allograft that is used to replace the autograft may be necessary in up to 20% of patients at 20 years.

The Ross operation: mid-term results

BACKGROUND

The Ross operation, although more demanding, is now widely accepted as an alternative solution for aortic valve replacement in young adults and children. A review of our experience to assess the mid-term results with the Ross operation is presented.

METHODS

From June 1991 through October 1997, 80 patients (mean age, 31 years) underwent aortic valve or root replacement with pulmonary autografts. Indications for operation were predominant aortic stenosis in 38 patients, aortic incompetence in 42 patients including endocarditis in 3 patients. Congenital lesions were present in 57 patients, either at pediatric (27 patients) or adult age (30 patients). Transthoracic echocardiography was performed preoperatively in all patients and serially after operation with the aims of measuring aortic and pulmonary annuli, evaluating transvalvular gradients and incompetence, and studying the left ventricular function. Intraoperative transesophageal echocardiography was used routinely. Complete root replacement was performed in 52 patients, intraluminal cylinder in 25 patients, and subcoronary implantation in 3 patients.

RESULTS

One patient died in the early postoperative period (1.2%). There was no late death. The actuarial survival at 5 years was 98%+/-1%. All survivors remained in New York Heart Association functional class I and were free of complications and medications. No gradient or significant aortic incompetence could be demonstrated in 73 patients. One patient developed late aortic incompetence grade 3 and reoperation is considered. On the pulmonary outflow tract, 6 patients had gradients between 20 and 40 mm Hg as calculated on echocardiography.

CONCLUSIONS

The pulmonary autograft gives excellent mid-term results with low mortality and no morbidity. It completely relieves the abnormal loading conditions of the left ventricle, resulting in a complete recovery of left ventricular function in most patients.

Aortic root dilation after the Ross procedure

This study evaluated changes in neoaortic root geometry in patients who underwent the Ross procedure. Serial postoperative echocardiographic measurements of the neoaortic root indexed to the square root of body surface area (centimeters divided by meters) were obtained from 30 patients (age range 3.1 to 31.4 years) and compared with paired preoperative and immediate postoperative values. Normal aortic root diameter Z scores were derived from root dimensions obtained from 217 healthy controls. Compared with preoperative values, an immediate stretch of the neoaortic versus pulmonary root (annulus and sinuses of valsalva) was observed at a mean follow-up period of 1 week. Additional aortic annular dilation from baseline prehospital discharge values was observed at 2 to 12 months (baseline vs follow-up annulus Z score: 1.4 vs 2.6, p <0.01, n = 16) and at 16 to 33 months follow-up (0.8 vs 2.0, p <0.05, n = 12). In a similar fashion, there was additional enlargement of the aortic sinus from its stretched state at hospital discharge at 2 to 12 months (baseline vs follow-up sinus Z score: 2.0 vs 3.3, p <0.01, n = 17) and at 16 to 33 months (1.7 vs 3.0, p <0.01, n = 13). There were no differences in root size between 2 to 12 and 16 to 33 months after surgery. There was a decrease in left ventricular size with no alteration in blood pressure or degree of aortic valve regurgitation. Thus, aortic root dilation occurs up to the first year after the Ross procedure but does not appear to progress beyond this time.

The influence of size mismatch on the hemodynamic performance of the pulmonary autograft in vitro

OBJECTIVES

We established an in vitro model to investigate the effect of size mismatch between the aortic and pulmonary root on the hydrodynamic performance and leaflet motion of the pulmonary autograft.

METHODS

Ten fresh porcine pulmonary roots (annulus diameter: 19-25 mm) were tested in a pulsatile flow simulator. The autografts then were implanted in fresh porcine aortic roots (annulus diameter: 19-30 mm) and retested in the flow simulator. Three roots were oversized by 21-39%, three were undersized by 32-45% and there were four size for size implantations. The external diameter of the roots and autografts was measured at the sinotubular junction at hydrostatic pressures of 0 - 120 mmHg. The transvalvular gradient and regurgitation were also measured and the effective orifice area was calculated. The leaflet motion was recorded on video.

RESULTS

The fresh pulmonary roots were more compliant than the fresh aortic roots (46 +/- 8.4% vs. 35 +/- 7.8% dilatation from 0 to 120 mmHg). The group of matching size autografts dilated by 43 +/- 4.9% in the same pressure range. The external diameter of the undersized autografts was 10 +/- 2.1% bigger than before implantation at 0 pressure and then the dilatation was 40 +/- 5.3% at 120 mmHg. The oversized implantation made the autografts 11 +/- 9.4% smaller in their relaxed state, but then they dilated by 65 +/- 11% as the pressure increased to 120 mmHg, resulting in a net dilatation of 54% over the original undilated state. The under or oversizing had little effect on the pressure gradient measured across the valves (5.6 +/- 2.57 mmHg before, 6.3 +/- 3.27 mmHg after implantation). Only the oversized valves showed significantly higher gradients than the native pulmonary valves. The effective orifice area of the undersized autografts was slightly bigger and the oversized autografts was slightly smaller after implantation, although the differences were not significant. The size mismatch did not cause regurgitation on the valves. The video images showed very low-open leaflet-bending deformation, both on the fresh pulmonary and the autograft valves.

CONCLUSION

Under or oversizing the pulmonary autograft up to 40% of the annulus diameter did not affect the hydrodynamic parameters significantly. The compliance of the autograft root was able to compensate for the size mismatch without adversely influencing the valve performance.

[Aortic valve replacement with a pulmonary autograft (the Ross operation) in adult and pediatric patients. A preliminary study]

INTRODUCTION AND OBJECTIVES

Aortic valve replacement with the patients own pulmonary autograft (the Ross procedure) is by now, the best surgical method for the replacement of the diseased aortic valve in certain groups of patients, this is particularly true for young adults and children or neonates with complex left ventricular outflow tract obstructions. The procedure was described by Donald Ross in 1967, and many years have passed. So in view of the accumulated experience the indications have extended to a wide group of patients which include children, neonates and young adults with formal contraindications for anticoagulation. In this publication we present our experience and our preliminary results in a group of fifteen patients which include adult and pediatric.

MATERIAL AND METHODS

In six patients the etiology of lesion was congenital and in the remainder nine the valve had an acquired lesion. Two patients had an open heart procedure before this operation both of them to relieve an obstruction to the left ventricular outflow tract. In this group of patients the Ross procedure was carried out inserting the pulmonary autograft in the aortic position as a total root which was always reconstructed with cryopreserved pulmonary homograft, the mean homograft diameter was 26.1 +/- 4 mm (19-35).

RESULTS

In all patients a transesophageal echocardiogram was performed in the operating room and postoperative, 1 or 2 months later. Only in one patient a mild aortic regurgitation was detected, no significant transaortic or transpulmonary gradients were detected postoperative. One patient was reoperated for bleeding in the postoperative course, there was no hospital mortality in our group and all the patients had an uneventful postoperative period. In the short term follow-up (41-155 days). All the patients are free of anticoagulant therapy, all them are in New York Heart Association Functional Class I.

CONCLUSIONS

The patients presented in this publication which include adult and pediatric, are the first group of patients operated in our country with some excellent preliminary results. We hope that this procedure will become popular and that other surgical groups will adopt it as another surgical tool to replace a diseased aortic valve.

Cryopreserved homograft valves in the pulmonary position: risk analysis for intermediate-term failure

OBJECTIVE

The purpose of this study was to examine the durability of cryopreserved homografts used to replace the "pulmonary" valve and to identify factors associated with their late deterioration.

METHODS

We reviewed our entire experience (1985-1997) with 331 survivors in whom cryopreserved homograft valves (pulmonary, n = 304; aortic, n = 27) were used to reconstruct the pulmonary outflow tract. Median age was 14 years (range, 2 days-62 years). Operations included Ross operation (n = 259), tetralogy of Fallot (n = 41), truncus arteriosus (n = 14), Rastelli operation (n = 11), and others (n = 6). Median follow-up was 3.8 years (range, 0.2-11.2 years); late echographic follow-up was complete for 97% of patients. Homograft failure was defined as the need for explantation and valve-related death; homograft dysfunction was defined as a pulmonary insufficiency grade 3/4 or greater and a transvalvular gradient of 40 mm Hg or greater.

RESULTS

Homograft failure occurred in 9% (30 of 331 patients; Kaplan-Meier); freedom from failure was 82% +/- 4% at 8 years. Homograft dysfunction occurred in 12% (39 of 331 patients), although freedom from dysfunction was 76% +/- 4% at 8 years. For aortic homografts, this was 56% +/- 11%, compared to 80% +/- 4% for pulmonary homografts (P =.003). For patients aged less than 3 years (n = 38), this was 51% +/- 12%, compared with 87% +/- 4% for older patients (P =.0001). By multivariable analysis, younger age of homograft donors, non-Ross operation, and later year of operation were associated with homograft failure; younger age of homograft donors, later year of operation, and use of an aortic homograft were associated with homograft dysfunction.

CONCLUSIONS

Homograft valves function satisfactorily in the pulmonary position at mid-term follow-up. The pulmonary homograft valve appears to be more durable than the aortic homograft valve in the pulmonary position.

Aortic root replacement in adolescents and young adults: composite graft versus homograft or autograft

BACKGROUND

Aortic root replacement (ARR) is a technically demanding procedure that can be performed using a variety of prosthetic devices. Root replacement in the young, but grown-up, patient poses unique problems in terms of the long-term outcome and active lifestyle that must be guaranteed by this operation. To identify the "ideal" substitute for ARR in the young, clinical results in teenagers and young adults (<35 years) operated on in the past two decades were reviewed.

METHODS

Thirty-eight patients younger than 35 years underwent ARR between January 1980 and December 1996. Eighteen patients, aged 30+/-5 years, had ARR with composite graft (group 1), whereas 20 patients, aged 28+/-6 years, had ARR with aortic homografts or pulmonary autografts (group 2). Primary indication for the operation was aortic insufficiency with anuloaortic ectasia (12 of 18) in group 1 and aortic insufficiency with or without anuloaortic ectasia (16 of 20) in group 2. Urgent ARR was required in 3 (17%) group 1 patients and 1 (5%) group 2 patient (p = 0.01).

RESULTS

Operative deaths were 2 (11%) in group 1, caused by hemorrhage and low output, and none in group 2. There were 4 (25%) late deaths in group 1, caused by embolism (2), hemorrhage, and myocardial infarction, and 1 (5%) in group 2, caused by arrhythmia. Survival was 81% +/- 9%, and 55%+/-18% at 2 and 10 years in group 1 versus 94%+/-5% at 2 years in group 2 (p = 0.04). Freedom from valve-related events was 93%+/-6% and 62%+/-18% at 2 and 10 years in group 1 versus 100% at 2 years in group 2 (p = 0.02). Freedom from reoperation in group 1 was 75% +/- 22% at 10 years, whereas no reoperations were done in group 2. Seven (58%) group 1 patients versus 1 (5%) group 2 patient were on cardiac medications (p = 0.001), and 11 (92%) group 1 patients versus no group 2 patients were on warfarin therapy at follow-up. All survivors were back to school or prior employment.

CONCLUSIONS

Survival early after ARR does not differ depending on the type of prosthesis. Valve-related events are common, and reoperation may be needed late after ARR with composite grafts. Despite limited follow-up with biologic devices, the prevalence of complications with composite grafts makes homograft or autograft ARR preferable in adolescents and young adults.

Immunogenic human leukocyte antigen class II antigens on human cardiac valves induce specific alloantibodies

BACKGROUND

The kinetics of panel reactive antibodies (PRA) and incidence of antibodies directed against human leukocyte antigen (HLA) class II were studied in patients who received a cryopreserved cardiac valve allograft.

METHODS

A complement-dependent microlymphocytotoxicity test was used to determine the percentage of panel reactive antibodies. Anti-HLA class II antibodies were measured by two-color fluorescence assays.

RESULTS

The panel reactive antibodies became positive in 25 (78%) of 32 recipients between 1 and 16 months after implantation. Antibodies against HLA class II antigens were detected in 11 (37%) of 30 patients. In 9 (82%) of 11 cases these antibodies were donor specific. The induction of antibodies against donor HLA class II antigens suggests that intact HLA class II antigens are expressed by viable cells within the graft. Dithiothreitol analysis showed that the antibodies were of the immunoglobulin G type. Apparently, the HLA class II antigens are expressed in an immunogenic way, as activation of specific T-helper cells is essential for the switch from immunoglobulin M to immunoglobulin G antibodies.

CONCLUSIONS

Allogeneic valve transplantation is associated with the production of donor-specific anti-HLA class I and II antibodies that could contribute to graft failure. This possibly detrimental effect might be prevented by cross matching in sensitized patients.

Cardiopulmonary response to maximal exercise in young athletes following the Ross procedure

BACKGROUND

Aortic prosthetic devices offer limitations that make them less than optimal valve substitutes because the vast majority are innately obstructive, especially at increased levels of hemodynamic function. The present study is designed to demonstrate the hemodynamics of the pulmonary autograft in 11 conditioned athletes who have undergone the Ross (pulmonary autograft) procedure. Data was compared to a group of 13 age-matched "normal athletes."

METHODS

All the Ross athletes had undergone the autograft procedure using the root replacement technique and were at least 3 months into their postrecovery phase. All athletes (both normal and Ross) underwent resting transthoracic echo followed by maximal exercise stress test (modified Bruce protocol) to exhaustion. Post-operative transesphogeal echocardiogram obtained within 90 seconds documented aortic valve gradient and velocity across the aortic valve.

RESULTS

In the Ross athlete group, maximum heart rate was 188 beats per minute, peak aortic valve gradient at rest (mm Hg) 7.69 (mean), velocity across the aortic valve at rest (cm per second) 129.40 (mean), peak aortic valve gradient at maximal exercise (mm Hg) 16.30 (mean), velocity across the aortic valve at maximal exercise (cm per second) 190.00 (mean). In the normal athlete group, maximum heart rate was 176 beats/minute, peak aortic valve gradient at rest (mm Hg) 5.97 (mean), velocity across the aortic valve at rest (cm per second) 120.54 (mean), peak aortic valve gradient at maximal exercise (mm Hg) 14.61 (mean), velocity across the aortic valve at maximal exercise (cm per second) 190.23 (mean).

CONCLUSION

The pulmonary autograft exhibits hemodynamic characteristics similar to the normal human aortic valve under conditions of enhanced cardiac output.

Truncus arteriosus: ten-year experience with homograft repair in neonates and infants

BACKGROUND

Early complete repair of truncus arteriosus with homograft reconstruction of the right ventricular outflow tract was performed and long-term results were evaluated.

METHODS

Review of 46 consecutive patients with truncus arteriosus who underwent primary correction between June 1987 and May 1997 was performed. Ages ranged from 21 days to 7.2 years (median, 62 days) and weights from 1.8 to 21.5 kg (median, 3.4 kg). Ten patients were operated on before 1 month of age, 20 between 1 and 3 months, 13 between 3 months and 1 year, and 3 at an older age. Associated cardiac conditions were encountered frequently, the most common being coronary artery anomalies (n = 16), truncal valve incompetence (n = 12), and interrupted aortic arch (n = 5). The right ventricular outflow tract was reconstructed with an aortic (n = 28) or a pulmonary homograft (n = 18).

RESULTS

There were two hospital deaths (4.3%). Both patients had severe truncal valve regurgitation and interrupted aortic arch together with other unfavorable conditions. Survival in uncomplicated truncus arteriosus was 100%. Follow-up was from 3 months to 10 years (mean, 36 months). There was one late death 4 months after the initial repair, presumably because of cardiac reason. Actuarial survival was 93% at 4 months and beyond. Actuarial freedom of reoperation in the 27 hospital survivors with aortic homografts was 43% at 75 months; it was 73% at 62 months in the 17 patients surviving with pulmonary homografts.

CONCLUSIONS

Neonatal or early infancy complete repair is the treatment with the best potential for survival. The homograft remains our conduit of choice to establish continuity between the right ventricle and the pulmonary artery. Management of severe truncal valve incompetence remains a surgical challenge.

[Long-term results of aortic root replacements with pulmonary autografts (Ross procedure) in five cases]

Aortic root replacement with a pulmonary autograft (the Ross Procedure) has been successfully performed in our hospital since November, 1992. The long-term results of five of the earliest cases are reported in this paper (2-3 year follow-up). The patients' ages were two months to eighteen years old. Four of the patients suffered from aortic valve stenosis, and one suffered from aortic regurgitation. Severe left ventricular failure was recognized in three cases. However, the patients recovered from surgery smoothly and without significant aortic regurgitation and left ventricular outflow tract gradients. A serious concern exist as to whether the implanted autograft in 2 months old infant would grow. In this patient, postoperative cardiac catheterization was performed after sixty days, one year, and two years. The diameter of the anulus of the pulmonary autograft enlarged from 12 mm to 18 mm over the period of two years. Compared with the calculated aortic valvular diameter from a standardized body surface area, these diameters were equivalent to 150%-162% of the standardized size at each age. The implanted pulmonary autograft has subsequently enlarged gradually and proportionally. Its function as an aortic valve was maintained even after significant enlargement of the aortic anulus to 18 mm. We therefore conclude that the Ross procedure can be recommended because of the apparent ability the pulmonary autograft to grow over time.

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.

Tissue chimerism in human cryopreserved homograft valve explants demonstrated by in situ hybridization

BACKGROUND

The presence of viable cells may contribute to increased homograft valve durability. These cells may be of infiltrating recipient or persisting donor origin. In this study, in situ hybridization was used to assess the origin of cells in cryopreserved homograft valve explants.

METHODS

A total of 10 homografts with a donor-recipient gender mismatch were acquired from patients whose graft had been explanted at reoperation or at autopsy. The period of implantation varied from 14 days to 70 months. Frozen sections were made and alternately examined with hematoxylin and eosin staining and in situ hybridization. Male cells were distinguished from female using a biotinylated Y-chromosome-specific deoxyribonucleic acid probe.

RESULTS

No endothelial cells were found. Thirty percent of the leaflets showed large acellular zones and 30% were completely acellular. The homograft arterial wall was occupied by a vast majority of penetrating host fibroblasts in 80% of the studied specimens. Donor and recipient cells were coexistent in the wall in 60% of the studied specimens and in 50% of the leaflets. In 30% only host cells could be identified.

CONCLUSIONS

This finding of tissue chimerism may lead to new insights in homograft pathology. The technique of in situ hybridization may provide an indispensable contribution in further homograft research.

Aortic root replacement with a pulmonary autograft in young adults: medium-term results in 70 patients

BACKGROUND

Pulmonary autograft aortic valve replacement has been introduced in our institution in selected adult patients in light of the known disadvantages and limitations of conventional prosthetic valves.

METHODS

We prospectively evaluated the use of the pulmonary autograft in a series of 70 young adults (31.2+/-8.7 years, range 16 to 49 years) operated on from March 1992 to April 1997 with aortic root replacement only.

RESULTS

There were no in-hospital deaths and two noncardiac-related late deaths during follow-up of up to 62 months (mean 33 months). Thromboembolic complications were not observed. One patient required reoperation for infective endocarditis 4.3 years after surgery. Discharge echo-Doppler studies showed normal autograft and allograft valve function. Serial echo-Doppler studies showed no significant progression of aortic insufficiency and no dilatation of the autograft. A severe stenosis of the pulmonary allograft developed in 1 patient.

CONCLUSION

Aortic root replacement with a pulmonary autograft, although more complex than conventional prosthetic valve replacement, is a safe, effective, and reproducible procedure in properly selected adult patients. Long-term results remain to be evaluated.

Comparison of Ross procedures and aortic valve allografts in children

BACKGROUND

The Ross procedure is useful, but at times an allograft valve is the only alternative to a mechanical aortic prosthesis. Since 1994 the Ross procedure or aortic allograft replacement has been used exclusively for aortic valve replacement at our institution.

METHODS

Demographic, clinical, and echocardiographic data of 23 consecutive Ross and 8 allograft patients were compared.

RESULTS

Groups were similar in age and weight. The Ross group had fewer prior operations. There were no deaths or major complications in either group. The Ross group had no late complications of the autograft but 1 reoperation for pulmonary allograft stenosis. In the allograft group there was one reoperation for allograft insufficiency. Echocardiography was performed 2 to 11 days (mean, 4.3 days) after operation and 1 to 28 months (mean, 10.2 months) later. In the Ross group left ventricular wall thickness (mm) decreased from 11.0 +/- 2.3 to 7.8+/-1.7 (p < 0.0001), and left ventricular outflow tract maximal systolic velocity (m/sec) decreased from 1.9 +/-0.6 to 1.4+/-0.4 (p = 0.0001). In the allograft group left ventricular wall thickness (mm) decreased from 10.5 +/-2.6 to 9.0+/-2.6 (not significant), and left ventricular outflow tract maximal systolic velocity (m/sec) increased from 1.5+/-0.9 to 1.9+/-0.7 (not significant).

CONCLUSIONS

The Ross procedure results in significant improvement in left ventricular wall thickness and outflow tract velocity not seen in allograft aortic valve replacements. The Ross procedure remains the preferred operation for children requiring aortic valve replacement.

The Ross Procedure: current registry results

BACKGROUND

The pulmonary autograft procedure for the treatment of aortic valve disease was developed and performed by Ross in 1967. The results he published in 1987 prompted increasing interest in the procedure. The International Registry of the Ross Procedure was established in 1993 to further examine longitudinal clinical outcomes.

METHODS

The results from the Ross registry document the continued and growing interest in the procedure with 2,523 patients currently enrolled, representing 122 centers and 166 surgeons worldwide.

RESULTS

Mortality (1987 to present) reported in the registry is 2.5%. It should be noted that follow-up stands at 70%. The most important issues for the registry to track are the incidence of reoperation for autograft failure and the fate of the pulmonary homograft. Reoperation for all valve-related problems is low (5.4%), with an autograft explant rate of 1.9%. Overall registry data indicate that the right ventricular outflow tract revision rate is 2.8%, with this decreasing by half to 1.3% in the 1987 to present subgroup.

CONCLUSIONS

Rigorous analysis of outcomes is difficult with registry follow-up currently at 70%; however, the general conclusions derived from the registry are supported by other individual series with excellent follow-up. Success of the registry depends on judicious efforts by all participating surgeons and coordinators in documenting long-term patient results and reporting them to the registry.

Clinical performance of the native pulmonary valve in the systemic circulation

BACKGROUND AND AIM OF THE STUDY

In a number of corrective and palliative procedures the autologous pulmonary valve is used as the systemic semilunar valve. This study reviews the surgical results and function of the native pulmonary valve in the systemic position after various surgical procedures.

METHODS

Between January 1994 and December 1997, the autologous pulmonary valve was transferred functionally or anatomically into the systemic circulation in 89 patients. Follow up echocardiograms and cardiac angiograms were reviewed for 51 neonates with transposition of the great arteries after an arterial switch operation (ASO), in 21 patients after first-stage palliation of hypoplastic left heart syndrome (HLHS), in eight children and adults with pulmonary autograft aortic valve replacement (Ross procedure), and in nine patients with a pulmonary artery-to-aortic anastomosis (Damus-Kaye-Stansel (DKS) procedure) in complex heart defects with outflow obstruction.

RESULTS

Nine patients (five with HLHS) died; thus, overall mortality rate was 10.2%. There was no evidence of valve-related mortality. Trivial insufficiency following ASO was noted in 11 patients, with no progression of incompetence over time. None of the HLHS patients had pulmonary insufficiency preoperatively, but all showed mild regurgitation on postoperative echocardiography. There was a moderate increase in insufficiency which was attenuated after an early second-stage palliation. Three of nine patients undergoing a DKS anastomosis demonstrated a hemodynamically insignificant insufficiency. Modification of the surgical technique avoided postoperative regurgitation. Four of seven patients having a Ross procedure showed trivial but non-progressive neoaortic regurgitation.

CONCLUSIONS

Based on this experience, the autologous pulmonary valve performs adequately at intermediate term follow up. Postoperatively, trivial regurgitation was a frequent finding but was hemodynamically insignificant. Progression or late development of insufficiency as well as stenosis were rare problems.

Gradient echo MRI for measurement of the pulmonary autograft diameter after transplantation to the aortic root: validation and comparison with ultrasound

The purpose of this study was to s the value of MRI for measurement of pulmonary autograft diameters after transplantation to the aortic root in adults. Thirty-eight adults underwent this operation. MRI and transesophageal echocardiography (TEE) were performed in 30 and 27 patients, respectively, after a mean follow-up period of 2.8 years. For internal validation of MRI, measurements at the diastolic short and long axes of the sinus level were used. Pulmonary autograft diameters were measured and compared with MRI and TEE at five different levels: the subannular region (1), annulus (2), sinus (3), sinotubular junction (4), and the distal part of the autograft (5). The correlation coefficient (r2) between long- and short-axis measurements for corresponding sinuses was .97. Diameters obtained with MRI were 1 to 3 mm larger than those obtained with TEE (P < .05), except for the annulus at systole (P > .3). Cine gradient echo MRI is an appropriate technique to evaluate pulmonary autograft diameters during follow-up. Concordance with TEE was good, apart from a systematic difference of approximately 2 mm.

The Ross operation: do native aortic, native pulmonary, and homograft pulmonary valve size and form differences influence results?

BACKGROUND

The pulmonary autograft approaches the ideal aortic valve substitute but numerous technical modifications are debated. The valves involved often differ in diameter and shape of the recipient annulus. We previously reported simplified surgical rules and early results of 52 patients and here we extend the report to 76 patients and analyze the mid-term results with respect to valve mismatch.

METHODS

We studied the influence of geometric discrepancies. Valve regurgitation and gradient are compared for size discrepancies up to or more than 3 mm between recipient annulus and pulmonary autograft. The normal tricuspid recipient aortic annulus is compared with the flat circular redo-prosthetic or bicuspid annulus. Patients with plication of the aortic annulus and remodeling of the distal aorta are reviewed, and lastly donor homograft to pulmonary autograft discrepancies up to and more than 3 mm are compared.

RESULTS

The results were comparable in all groups and no significant differences were observed.

CONCLUSION

The pulmonary autograft operation may be simplified, with good results at the least in the first year despite operative tailoring due to valve discrepancies.

Late homograft valve insertion after transannular patch repair of tetralogy of Fallot

BACKGROUND AND AIMS OF THE STUDY

Transannular patch repair of tetralogy of Fallot leads to pulmonary insufficiency and progressive right ventricular dilatation responsible for a decreased exercise capacity. We studied the impact of late homograft insertion on the regression of the right ventricular volumes in symptomatic patients.

METHODS

Between July 1992 and August 1996, 15 consecutive patients (age range: 4 to 24 years) were operated on at a median of 13 years (range: 3 to 20 years) after transannular patch repair of tetralogy of Fallot. All patients complained of exertional dyspnea and fatigue. Syncopes were reported in six patients and four patients had sustained episodes of ventricular tachycardia. Fourteen had pulmonary regurgitation grade 3 or 4 and one had an associated stenosis and insufficiency. All patients had a dilated right ventricle. At reoperation, no patients presented with major aneurysm. The patch was resected and the right ventricular outflow tract reconstructed with a cryopreserved pulmonary homograft. Right ventricular volumes were studied before the procedures and at the last follow up consultation.

RESULTS

There was no operative death. One patient who had a concomitant patch repair of a hypoplastic left pulmonary artery needed extracorporeal circulatory support for eight days. After a median follow up of 25 months (range: 3 to 54 months) all patients but one are in NYHA class I. There were no late deaths. The mean end-diastolic diameter of the right ventricle decreased from 36 +/- 9 mm before surgery to 31 +/- 6 mm (not significant). The mean ratio between the end-diastolic diameter of the right and left ventricles decreased from 0.94 +/- 0.3 to 0.74 +/- 0.2 (p < 0.01).

CONCLUSION

An increasing number of patients who had transannular patch repair for tetralogy of Fallot will require reoperation for symptomatic long-term pulmonary regurgitation. Homograft reconstruction of the right ventricular outflow tract of these patients induces regression of their right ventricular dilatation and leads to their functional recovery.

Geometric mismatch of pulmonary and aortic anuli in children undergoing the Ross procedure: implications for surgical management and autograft valve function

BACKGROUND

There is often substantial mismatch between the diameters of the pulmonary and aortic anuli in young patients with systemic outflow tract disease. To implant the autologous pulmonary valve in the aortic position under such circumstances, it is necessary to adapt the geometry of the systemic outflow tract. The effects of such adaptations on autograft function in children are not well known.

METHODS

To determine factors predictive of autograft regurgitation, we analyzed 41 cases of children who have undergone the Ross procedure. The diameter of the pulmonary valve was greater (by at least 3 mm) than that of the aortic valve in 20 cases, equal (within 2 mm) in 12 cases, and less (by at least 3 mm) in nine cases, with differences ranging from +10 to -12 mm. In 12 patients with a larger pulmonary anulus, aortoventriculoplasty was used to correct the mismatch. In patients with a larger aortic anulus, the mismatch was corrected by gradual adjustment along the circumference of the autograft, rather than by tailoring of the native aortic anulus.

RESULTS

At follow-up (median 31 months), two patients had undergone reoperation on the neoaortic valve for moderate regurgitation. In the remaining 38 cases, autograft regurgitation was as follows: none or trivial in 30, mild in seven, and moderate in one. There was no correlation between regurgitation and age, geometric mismatch, or previous or concurrent procedures.

CONCLUSIONS

Subtle technical factors that may result in distortion of the valve complex are probably more important determinants of autograft regurgitation than are indication for repair, geometric mismatch, or previous or concomitant outflow tract procedures. Significant mismatch of the semilunar anuli is not a contraindication to the Ross procedure in children.