Pulmonary autograft replacement in children. The ideal solution?

Finite Element Analysis Investigate Pulmonary Autograft Root and Leaflet Stresses to Understand Late Durability of Ross Operation

Ross operation might be a valid option for congenital and acquired left ventricular outflow tract disease in selected cases. As the pulmonary autograft is a living substitute for the aortic root that bioinspired the Ross operation, we have created an experimental animal model in which the vital capacity of the pulmonary autograft (PA) has been studied during physiological growth. The present study aims to determine any increased stresses in PA root and leaflet compared to the similar components of the native aorta. An animal model and a mathematical analysis using finite element analysis have been used for the purpose of this manuscript. The results of this study advance our understanding of the relative benefits of pulmonary autograft for the management of severe aortic valve disease. However, it launches a warning about the importance of the choice of the length of the conduits as mechanical deformation, and, therefore, potential failure, increases with the length of the segment subjected to stress. Understanding PA root and leaflet stresses is the first step toward understanding PA durability and the regions prone to dilatation, ultimately to refine the best implant technique.

Pulmonary autograft in aortic position: is everything known?

The Ross operation provides several advantages compared to other valve substitutes to manage aortic valve disease, such as growth potential, excellent hemodynamics, freedom from oral anticoagulation and hemolysis, and better durability. However, progressive dilatation of the pulmonary autografts after Ross operation reflects the inadequate remodeling of the native pulmonary root in the systemic circulation, which results in impaired adaptability to systemic pressure and risk of reoperation after the first decade. A recently published article showed that remodeling increased wall thickness and decreased stiffness in the failed specimens after Ross operation, and the increased compliance might play a key role in determining the progressive long-term autograft root dilatation. Late dilatation can be counteracted by an external barrier which prevents failure. Therefore, an inclusion cylinder technique with a native aorta or a synthetic external support, such as Dacron, might stabilize the autograft root and improve long-term outcomes. In this article, we offer a prospective about the importance of biomechanical features in future developments of the Ross operation. Pre-clinical and clinical evaluations of the biomechanical properties of these reinforced pulmonary autografts might shed new light on the current debate about the long-term fate of the pulmonary autograft after Ross procedure.

Biomechanics drive histological wall remodeling of neoaortic root: A mathematical model to study the expression levels of ki 67, metalloprotease, and apoptosis transition

The pulmonary artery autograft (PA) is the ideal substitute for aortic valve disease in children and young adult. However, it is harnessed by the issue of long-term dilation and regurgitation, often requiring surgery. PA implanted in aortic position during the growth phase in children undergoes a process of mechanical remodeling. We previously developed a semiresorbable armored prosthesis able to mechanically sustain the neoaorta preventing dilation and to gradually integrate with the PA wall inducing a progressive arterial-like tissue positive remodeling. We also described the mechanisms of growth, remodeling and stress shielding of the reinforced PA through a mathematical model. We sought to demonstrate the biological counterpart and the potential molecular mechanisms underlying this histological and mechanical remodeling. A specific mathematical model was developed to describe mechanical behavior of the PA. Mallory trichrome red staining and immunohistochemistry for MMP-9 were performed to elucidate extracellular matrix remodeling phenomena. Apoptosis and cell proliferation were determined by TUNEL assay and immunohistochemistry for Ki67, respectively. An histological remodeling phenomenon sustained by increased level of MMP-9, augmented cell proliferation and reduced apoptosis in the reinforced PA was demonstrated. The mathematical model predicted the biomechanical behavior subtended by the histological changes of the PA in these settings. Changes in metalloproteinases (MMP-9), cell proliferation and apoptosis are the main actors in the remodeling process occurring after transposition of the PA into systemic regimens. Use of semiresorbable reinforcements might induce a positive remodeling of the PA in the context of Ross operation. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2785-2793, 2016.

The Ross Operation: Clinical Results and Echocardiographic Findings

Between November 2001 and September 2004, 80 patients aged 11 to 56 years (mean, 27.6 years) underwent the Ross operation. The mean preoperative New York Heart Association functional class was 2.37 ± 0.72, and the mean ejection fraction was 52.8% ± 16%. Aortic involvement included stenosis in 19 (24%) patients, regurgitation in 22 (28%), and both in 39 (49%). Root replacement was the technique used in all cases. The mean hospital stay was 5 days, and 74 patients (93%) were followed up for 4–48 months. Four-year actuarial survival rate was 96.25%. Postoperative echocardiography revealed no pulmonary autograft insufficiency in 50 patients (63%), trivial to mild insufficiency in 22 (28%), moderate insufficiency in 2 (3%), and severe insufficiency in one (1%). Two patients required autograft re-intervention. Postoperative echocardiography of the pulmonary homograft valve showed severe stenosis (peak gradient > 50 mm Hg) in 2 patients, and moderate stenosis (peak gradient 25–50 mm Hg) in one. The mean postoperative left ventricular ejection fraction was 51.4%. The Ross operation can be considered an elegant alternative to prosthetic valves in the treatment of aortic valve diseases in developing countries.

Spectrum and outcome of reoperations after the Ross procedure

BACKGROUND

Proposed advantages to the Ross procedure included presumed increased freedom from reoperation and simpler reoperation for pulmonary conduit replacement if needed. It is increasingly apparent, however, that reoperations are frequent after the Ross procedure and that when required, they may be more complex than previously thought.

METHODS AND RESULTS

Between September 1991 and August 2008, 56 patients underwent reoperation at our institution after a Ross procedure performed by ourselves (n=13) or elsewhere (n=43). Median age at first reoperation at our institution was 26 years (range 1 to 69 years). The 4 most common indications for reoperation were isolated autograft (neoaortic) regurgitation in 11 cases (20), isolated pulmonary conduit regurgitation/stenosis in 9 (16), combined autograft regurgitation/dilatation in 8 (14), and combined autograft regurgitation and pulmonary conduit regurgitation/stenosis in 6 (11). A total of 144 procedures were performed in these 56 patients during first reoperation at our institution. The autograft valve required replacement in 21 cases (38) and aortic root replacement in 21 (38), with ascending aortic/arch reconstruction in 13 (23) and mitral valve surgery in 5 (9). The pulmonary valve was replaced in 33 cases (59) and the tricuspid valve was repaired/replaced in 10 (18). Early mortality was 1.8 (1 of 56 patients), and morbidity included 6 patients with respiratory failure and 3 who required postcardiotomy extracorporeal membrane oxygenation. There were 4 late deaths during the median follow-up of 8 months (range 1 to 179 months).

CONCLUSIONS

A broad spectrum of complex reoperations may be required after the Ross procedure. Patients and family members considering the procedure should be informed of the potential for associated morbidity should reoperation be necessary.

The Ross Procedure: Clinical and Echocardiographic Follow-Up in 219 Consecutive Patients

BACKGROUND

The replacement of the diseased aortic valve with a pulmonary autograft has been shown to provide excellent hemodynamic results and to be associated with low morbidity and mortality rates.

METHODS

From 1991 to 2005, 219 patients undergoing the Ross operation were identified. All patients underwent transthoracic echocardiography at discharge and were scheduled for a yearly study thereafter. The echocardiographic study consisted of a morphologic analysis of the pulmonary autograft with measurement of end-systolic diameters at three levels: annulus, sinuses of Valsalva, and origin of the ascending aorta 2 cm above the sinotubular junction. The dynamic analysis evaluated the function of the aortic autograft and the pulmonary homograft. Maximal and mean aortic and pulmonary transvalvular pressure gradients were investigated.

RESULTS

The 30-day mortality was 1.8% (n = 4). Cardiac deaths were not related to the autograft. The 10-year actuarial survival was 95.7% +/- 2.1%. Six patients (2.8%) had grade 2 autograft valve regurgitation. No grade 3 or 4 pulmonary regurgitation was identified. At their most recent follow-up, 28 patients (13.1%) had grade 1 insufficiency of the pulmonary homograft, and 10 patients (4.6%) had a peak transvalvular gradient of 17.9 +/- 10.2 mm Hg.

CONCLUSIONS

Our current experience suggests that replacement of the aortic root with a pulmonary autograft can be safely performed in infants, children, and adults and is associated with low mortality and morbidity rates. It constitutes an elegant alternative to the use of prosthetic valves in the treatment of aortic valve diseases.

Complications following the ross procedure: cardiac MRI findings

Aortic valve replacement with a pulmonary autograft (ie, Ross procedure) is a technique used in selected cases for the treatment of aortic valve disease. Aware of reports describing chronic complications after the Ross procedure such as aortic insufficiency, right ventricular outlet obstruction, aortic autograft dilatation, and pulmonary allograft stenosis, cardiac magnetic resonance imaging (MRI) was performed in individuals who had a previous Ross procedure (range 2 to 10 years earlier) to determine if these complications could be visualized by MRI. This case study presents the MRI findings of 5 patients (mean age: 42.0+/-7.8 years). In each patient, complications of the Ross procedure were observed. These results suggest that cardiac MRI has the potential to become a clinically important technique for evaluating post-Ross procedure patients.

Exercise performance in children and adolescents after the Ross procedure

OBJECTIVES

The Ross procedure is increasingly utilized in the treatment of aortic valvar disease in children and adolescents. Our purpose was to compare pre- and post-operative exercise state in this population.

METHODS

We included patients who underwent the Ross procedure at our institution between January, 1995, and December, 2003, and in whom we had performed pre- and post-operative exercise stress tests. We used a ramp bicycle protocol to measure consumption of oxygen and production of carbon dioxide. Cardiac output was estimated from effective pulmonary blood flow by the helium acetylene re-breathing technique.

RESULTS

We studied 26 patients, having a median age at surgery of 15.7 years, with a range from 7.5 to 24.1 years. The primary indication for surgery in two-thirds was combined aortic stenosis and insufficiency. Median time from the operation to the post-operative exercise stress test was 17.4 months, with a range from 6.7 to 30.2 months. There was a trend toward lower maximal consumption of oxygen after the procedure, at 36.3 plus or minus 7.6 millilitres per kilogram per minute (83.9% predicted) as opposed to 38.6 plus or minus 8.4 millilitres per kilogram per minute (88.5% predicted, p equal to 0.06). Patients after the procedure, however, had significantly increased adiposity, so that there was no difference in maximal consumption of oxygen indexed to ideal body weight before and after the operation. In 20 of the patients, aerobic capacity improved or was stable after the operation. There was no post-operative chronotropic impairment.

CONCLUSIONS

In the majority of patients following the Ross procedure, exercise performance is stable and within the normal range of a healthy age and sex matched population, despite sedentary lifestyles and increased adiposity.

Tissue engineering of an auto-xenograft pulmonary heart valve

To improve the durability of stentless valves without losing their excellent hemodynamic function, a new-generation auto-xenograft was developed and evaluated. A piece of vein was harvested from 3 juvenile sheep 6 weeks before implantation of the valve. Endothelial cells from the vein material were cultivated and used to reendothelialize a decellularized porcine pulmonary valve. The tissue-engineered valve was implanted into the right ventricular outflow tract of the juvenile sheep. It was explanted after 100 days and assessed macroscopically as well as by x-ray, light microscopy (hematoxylin and eosin staining and von Kossa staining), and scanning electron microscopy. Calcium content of the cusps was determined quantitatively by atomic absorption spectrometry. The sheep implanted with the valve recovered quickly without any problems during the observation period. X-ray examination of the 3 explanted valves showed no cusp calcification, which was confirmed by histological study. Atomic absorption spectrometry showed low tissue calcium content. A clinical safety and feasibility trial with an allograft valve prepared the same way showed excellent short-term results in 6 patients.

Aortic insufficiency: Indications for surgery in children

The goals of surgery in children with chronic aortic insufficiency are to prevent irreversible left ventricular dysfunction and to provide for long-term survival. In the past, surgical options included placement of a mechanical valve, a porcine bioprosthesis, or an aortic valve homograft. Complications from these options include thromboembolism, prosthetic valve endocarditis, limited durability, and lack of growth potential. The increasing utilization of the Ross procedure to treat chronic aortic insufficiency has led to new interest in the question of when to operate on a regurgitant aortic valve. This review focuses on the pathophysiology of aortic insufficiency and the invasive and noninvasive preoperative indices that may indicate the optimal time for aortic valve surgery in the pediatric population. Copyright 1998 by W.B. Saunders Company

The Ross procedure in children and young adults: a word of caution

BACKGROUND

Disease of the aortic valve in children and young adults is a complex entity whose management is the subject of controversy. The Ross and the Ross-Konno procedures have become the primary choices for aortic valve replacement in children because of growth potential, optimal hemodynamic performance, and lack of the need for anticoagulation. However, concern persists regarding the longevity of the pulmonary autograft, especially in patients with aortic insufficiency.

METHODS

Between June 1993 and February 2000, 72 Ross and Ross-Konno procedures were performed at our institution: 81% of the patients were less than 15 years old. Preoperative, postoperative, and follow-up clinical, echocardiographic, and hemodynamic data were reviewed. Statistical analysis was performed to identify the risk factors for deteriorating autograft function.

RESULTS

Aortic insufficiency was an indication for the Ross procedure in 17 patients and mixed lesions with predominant aortic insufficiency in 10. Of the 45 other patients, 32 had aortic stenosis and 13 had mixed lesions with predominant aortic stenosis. There were no deaths during a follow-up of 5 to 80 months. Autograft reoperation was necessary in the follow-up period in 7 patients for severe aortic insufficiency. Moderate insufficiency was identified in 5 additional patients. Aortic insufficiency or predominant aortic insufficiency, as a preoperative hemodynamic indication for the Ross procedure, reached statistical significance (P =.031) as a risk factor for autograft failure.

CONCLUSION

The Ross and the Ross-Konno procedures have changed the prognosis of children and young adults with complex aortic valve disease. However, the Ross procedure should be performed with caution in older children in whom aortic insufficiency is a preoperative hemodynamic indication. Further follow-up to delineate the risk factors for autograft dysfunction in children and young adults is necessary to better define the indications for the Ross procedure.

Hemodynamic performance during maximum exercise in adult patients with the ross operation and comparison with normal controls and patients with aortic bioprostheses

This study examines the resting and exercise hemodynamic performance of the pulmonary autografts in the aortic position as well as of the homografts used for right ventricular outflow reconstruction in patients undergoing the Ross operation. Previous studies have reported excellent resting hemodynamics in patients who underwent aortic valve replacement with a pulmonary autograft. However, there are very few studies of their hemodynamic performance during exercise. Twenty adult subjects who underwent the Ross operation and 12 normal control subjects were submitted to maximum romp bicycle exercise. The valve effective orifice areas and transvalvular gradients of both aortic (autograft) and pulmonary (homograft) valves were measured at rest and at peak of maximum exercise using Doppler echocardiography. Valve areas were indexed for body surface area. The hemodynamics of the aortic valve were very similar in Ross subjects and in control subjects at rest and during exercise. However, the indexed valve area of the pulmonary valve at rest was significantly (p < 0.001) lower in the Ross subjects (1.10 +/- 0.46 cm2/ m2) than in the control subjects (1.95 +/- 0.41 cm2/m2), resulting in higher (p = 0.004) mean gradients at rest (Ross: 9 +/- 7 mm Hg vs control: 2 +/- 1 mm Hg) and at peak exercise (Ross: 21 +/- 14 mm Hg vs control: 7 +/- 2 mm Hg). The pulmonary autograft provided excellent hemodynamics in the aortic position either at rest or during maximum exercise, whereas moderately high gradients were found during exercise across the homograft implanted in the pulmonary valve position. Future improvement of the Ross procedure should be oriented toward the search of new methods to prevent the deterioration of the homografts.

Serial echocardiographic measurements of the pulmonary autograft in the aortic valve position after the Ross operation in a pediatric population using normal pulmonary artery dimensions as the reference standard

Serial echocardiographic measurements of the annulus and sinus were obtained in children before the Ross operation, and early and late postoperatively. Values were compared with normal standards for the aorta and pulmonary artery (PA). There was no significant difference between PA annulus measurements before surgery and the corresponding autograft immediately afterward (1.73 +/- 0.60 cm preoperatively; 1. 63 +/- 0.58 cm postoperatively, p = NS). Late after surgery the mean annulus diameter was enlarged compared with the normal aorta (DeltaZ 1.9 +/- 2.4), but remained relatively unchanged compared with the normal PA (DeltaZ 0.7 +/- 1.1, p <0.01). In contrast, the autograft sinus was dilated early after surgery (1.83 +/- 0.58 cm preoperatively; 2.18 +/- 0.73 cm postoperatively, p <0.01). Mean sinus Z score further increased compared with both the aorta (DeltaZ 1.3 +/- 1.7) and PA (DeltaZ 1.3 +/- 1.6). Use of standard PA measurements may be important in the assessment of autograft enlargement. Minimal change in autograft Z scores over time suggests that annulus enlargement is mainly due to somatic growth. In contrast, the autograft sinus showed an immediate and continued disproportionate increase in size over time, suggesting that sinus enlargement is largely due to passive dilation.

Rapid enlargement of neoaortic root after the Ross procedure in children

Serial echocardiographic studies from 11 patients who underwent the Ross procedure were reviewed, and the rate of neoaortic annulus size increase was compared with that in a normal population. The rate of growth of the neoaortic annulus after the Ross procedure was significantly greater than that in the normal population.

Pulmonary autograft: should it be used in young patients with rheumatic disease?

BACKGROUND

Although pulmonary autograft is being increasingly used to replace the diseased aortic valve with excellent long-term results, its use in the population with rheumatic disease still needs careful evaluation.

PATIENTS AND METHODS

From October 1993 through March 1998, 102 patients underwent aortic valve replacement with a pulmonary autograft (Ross procedure). The mean age was 27.9 +/- 4.2 years (range, 0.8-56 years). The cause was rheumatic disease in 75 patients (73%), bicuspid aortic valve in 26 patients (26%), and myxomatous aortoarteritis in 1 patient (1%). The root replacement technique was used in all. In addition, 31 patients had 33 associated procedures: mitral valve repair (n = 15 patients), open mitral commissurotomy (n = 15 patients), tricuspid repair (n = 2 patients), and homograft mitral valve replacement (n = 1 patient).

RESULTS

Operative mortality was 6.9% (7 patients). Late mortality was 7.8% (8 patients). Follow-up ranged from 1 to 60 months (mean, 25.3 +/- 15.4 months) and was 98% complete. Two patients required reoperation for failed mitral valve repair, and 2 other patients underwent reoperation for failure of both the autograft and mitral valve repair. Echocardiographic assessment showed moderate to severe aortic regurgitation in 13 patients, along with thickening of the autograft. All of these patients had rheumatic disease and were young (<30 years). Ten of these patients had undergone associated mitral valve procedure. Morphologic and histopathologic examination of explanted autografts showed features compatible with rheumatic valvulitis.

CONCLUSION

Pulmonary autograft is susceptible to rheumatic involvement. Young age (<30 years) and associated mitral valve disease are significant risk factors for autograft failure in patients with rheumatic disease. Use of pulmonary autograft in this subgroup of patients requires a cautious approach.

Extended aortic root replacement with aortic allografts or pulmonary autografts in children

OBJECTIVES

To evaluate the early results and effectiveness of left ventricular outflow tract enlargement with aortic allograft or pulmonary autograft in children with complex left ventricular outflow tract obstruction.

METHOD

The records of 30 children who underwent aortic root enlargement and replacement with either an aortic allograft (22 patients) or pulmonary autograft (8 patients) between January 1987 and June 1997 were reviewed. The predominant diagnosis was complex left ventricular outflow tract obstruction (n = 19), associated with aortic incompetence in 11 children. Before root enlargement, 27 children underwent surgical valvotomy (14 patients), balloon dilatation (10 patients), or both interventions (3 patients). Mean age at root enlargement was 5.4 +/- 3.5 years (range, 2 days-16 years). Most of the children (27 patients) underwent a Konno aortoventriculoplasty. Concomitant septal myectomy was performed in 4 children, mitral valve procedure in 5 children, and endocardial fibroelastosis resection in 1 child.

RESULTS

Five children (17%) died in hospital. Four of these were infants less than 2 months old. All had acute aortic incompetence as the result of recent intervention necessitating urgent operation. The fifth child, aged 10 years, died of myocardial failure 2 weeks after the operation. During the follow-up period (mean length, 4.1 +/- 2.8 years), sudden death occurred in 1 child 3 months after the operation. Follow-up echocardiograms (obtained for 23 of the surviving 24 children within 3 +/- 2.3 years) showed a left ventricular outflow tract gradient reduced from a mean of 65 to 11 mm Hg (P =.001); Z value increased from a mean of -0.5 to 4.1 (P <. 001), and aortic incompetence was trivial or mild except in 2 children.

CONCLUSION

Urgent aortic root enlargement in decompensating neonates carries higher mortality rates. In older children, the early results of root enlargement and implantation of allograft or autograft are good.

The Ross operation: a 12-year experience

BACKGROUND

The Ross operation, originally introduced as a scalloped subcoronary implant with an 80% survival and 85% freedom from reoperation, has recently been modified to a root replacement which is now the most utilized implant technique. The mid and late results of this operative technique and comparison of intra-aortic implants and root replacement in a single institution are reported.

METHODS

The records of 328 patients who had a Ross operation at the University of Oklahoma (August 1986 to July 1998) were reviewed to assess operative technique and patient-related factors on survival, autograft valve function, homograft valve function, valve-related complications, and need for reoperation.

RESULTS

Operative survival was 95.4% with an actuarial survival of 89% +/- 5% at 8 years. Freedom from replacement of the pulmonary autograft was 94% +/- 3% at 8 years, freedom from reoperation on the pulmonary homograft was 90% +/- 4% at 8 years, and freedom from autograft valve reoperation or dysfunction (3+ autograft valve insufficiency) was 83% +/- 6% at 9 years. The incidence of autograft valve reoperation and late autograft valve dysfunction was decreased by root replacement. Annulus reduction and fixation improved early results in patients with aortic insufficiency and annulus dilatation.

CONCLUSIONS

Early results have been excellent, as the development of late autograft valve dysfunction or dilatation has been rare. The excellent hemodynamic results with a limited incidence of reoperation and replacement of the autograft valve justify its continued use.

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 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.

[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.

Perioperative conduction and rhythm disturbances after the Ross procedure in young patients

BACKGROUND

The Ross procedure is performed for a variety of left ventricular outflow tract diseases in children. The preoperative hemodynamic burden of pressure or volume overload and associated ventricular hypertrophy can predispose to ventricular arrhythmias. Additional procedures performed with the Ross procedure (eg, Konno) may damage the conduction system.

METHODS

Between January 1995 and February 1997, the Ross procedure was performed in 42 patients, 31 (74%) of whom had 71 prior interventions. Concomitant procedures (n = 42 in 23 patients) included 17 annular-enlarging procedures. Screening was performed for perioperative conduction and rhythm abnormalities.

RESULTS

There was one postoperative death. Perioperative ventricular tachycardia occurred in 12 patients (29%), with 2 receiving antiarrhythmic medication for ventricular tachycardia at discharge. Transient complete heart block occurred in 3 patients, all of whom had concomitant procedures performed in the subaortic area; all patients were discharged in sinus rhythm and no patient received a permanent pacemaker.

CONCLUSIONS

The Ross procedure can be performed successfully in children with complex cardiac disease with low mortality and perioperative morbidity. The incidence of perioperative ventricular tachycardia is high (29%), suggesting the need for vigilant perioperative monitoring and long-term surveillance.

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.

Caring for the former pediatric cardiac surgery patient

Because of marked improvements in the early diagnosis and management of patients with congenital heart defects as well as the dramatic increases in surgical survival for patients undergoing correction of these defects, a large and growing population of survivors of congenital heart surgery present themselves for care to primary care pediatricians. This article highlights the need for primary care pediatricians to understand the common clinical problems they will see in this group of patients and what surgical strategies are used in the more complex defects.

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.

Does the pulmonary autograft in the aortic position in adults increase in diameter? An echocardiographic study

OBJECTIVE

The objective of this study was to discern the fate of the pulmonary autograft diameter over time in adults and its relation to aortic regurgitation in the setting of aortic root replacement.

METHODS

From January 1989 to May 1995, 36 consecutive adult patients underwent aortic root replacement with a pulmonary autograft for aortic valve disease. The mean age of 20 male and 16 female patients was 29.1 years (range 19.3 to 52.1 years). The mean follow-up was 2.3 years (range 0.3 to 6.0 years). Two patients died in the hospital. One other patient had a second operation for stenosis at the distal suture line of the allograft in the pulmonary position. Pulmonary autograft anulus and sinus diameters were measured with epicardial echocardiography before (only anulus) and after cardiopulmonary bypass, with transthoracic echocardiography at hospital discharge, and with transesophageal echocardiography during follow-up.

RESULTS

The mean autograft anulus diameter did not increase immediately after cardiopulmonary bypass (mean diameter 26.2 mm before and 26.4 mm after cardiopulmonary bypass). The mean autograft sinus diameter after cardiopulmonary bypass was 36.5 mm. The mean autograft anulus diameter increased to 31.5 mm at follow-up, an increase of 5.1 mm (19%). The mean autograft sinus diameter increased to 43.9 mm at follow-up, an increase of 7.4 mm (20%). Fifty-nine percent of the anulus diameter increase and 40% of the sinus diameter increase was already reached at hospital discharge (7 to 10 days after the operation); the other part of the increase occurred during follow-up. Diameter increase was associated with neither the length of follow-up (follow-up less than 1 year compared with a longer follow-up) or severity of aortic regurgitation.

CONCLUSION

Pulmonary autograft anulus and sinus diameters increase the first year after aortic root replacement with a pulmonary autograft. This occurs rapidly within 10 days after the operation, with a further increase during follow-up, without causing significant aortic regurgitation at medium-term follow-up.

Aortic valve repair of congenital stenosis with bovine pericardium

BACKGROUND

Conservative surgical options in the treatment of congenital aortic stenosis are limited. To relieve the obstruction necessitates full incision of the raphe of the larger valve leaflet, but this inevitably causes prolapse.

METHODS

We performed aortic valve repair in 6 children, aged 14 months to 17 years, with congenital aortic stenosis, 2 having had aortic valvotomy as infants. The repair consisted of suturing the base of a triangular piece of bovine pericardium, with a simple vertical fold, to the free edges of the incised raphe. The pericardial fold was then sutured vertically to the aortic wall.

RESULTS

At follow-up of 2 to 60 months, the mean peak systolic Doppler gradients had decreased from 80 +/- 15 mm Hg to 26 +/- 9 mm Hg. The effective valvular orifice area increased from 33% +/- 6% to 64% +/- 3%, allowing blood flow to increase by a factor of 3.76. Two patients have mild and 2 have mild-to-moderate aortic regurgitation.

CONCLUSIONS

The described conservative repair renders the valve tricuspid and trisinusoidal, and the deficient interleaflet triangle is recreated, preventing cusp prolapse. Longer follow-up is required to assess the durability of unstented pericardium in the aortic position, but the early results are encouraging.

Ross procedure in congenital patients: results and left ventricular function

METHODS

From April 1990 to August 1995, 121 patients (median age 42 years) underwent aortic valve replacement with allografts (69 patients) or autografts (52 patients). In this latter group, 24 Ross procedures have been performed in congenital patients since November 1991 (median age 10 years, range five months to 27 years): aortic incompetence (n = 17), isolated aortic stenosis (n = 5), small stenotic prosthesis (n = 2). Transthoracic echocardiography was obtained preoperatively in all patients and serially after surgery with the aim of measuring aortic and pulmonary annuli and evaluate gradients and incompetence and to study the left ventricular function. Intraoperative transoesophageal echocardiography was routinely used. Complete root replacement was performed in all patients.

RESULTS

One patient died in the early postoperative period (4%). There was no late death. All survivors remained in NYHA class I and were free of complications and medications. No gradient nor any significant aortic incompetence could be demonstrated. In 17 patients with predominant aortic incompetence before surgery, the left ventricular function was followed prospectively, end-diastolic left ventricular dimensions diminished drastically from 2 +/- 3.4 S.D. above normal to -0.63 +/- 2.4 S.D. at one week postoperatively (day 10) to reach a normal value one to three months after surgery. Left ventricular mass remained abnormal at day 10 (from 4.7 +/- 3.3 S.D. to 5.3 +/- 3.8 S.D.) and diminished more progressively to reach a normal value (0.14 +/- 1.4 S.D.) at three months. This resulted in a significant decrease of end-systolic wall stress (-3.6 +/- 2.1 S.D.) and in a hyperdynamic function in the immediate postoperative days except in two patients. These two patients were characterized preoperatively by more severely dilated left ventricle (end diastolic dimension 5.3 +/- 0.03 versus 1.6 +/- 3 S.D.) with decreased left ventricular wall thickness (1.19 +/- 0.7 versus 3.44 +/- 1.9 S.D.), decreased ratio between end diastolic wall thickness and end diastolic dimension (0.14 +/- 0.06 versus 0.2 +/- 0.06) and a decreased velocity of shortening. Unlike the other 15 patients, the left ventricular function did not recover completely at mid term follow-up in those two patients.

CONCLUSION

The Ross operation is a safe procedure and allows us to suppress completely the abnormal loading conditions of the left ventricle, resulting in a complete recovery of left ventricular function in most patients.

Aortic valve replacement with a pulmonary autograft in infants with critical aortic stenosis

Seven patients with critical aortic stenosis underwent aortic valve replacement with a pulmonary autograft (the Ross operation) between the ages of 5 weeks and 9 months. The operation was considered mandatory for survival because of continued severe heart failure or valve avulsion. Six of the patients had undergone unsuccessful previous palliations, such as commissurotomy, balloon dilation, and transventricular valvotomy, performed singly (n = 1) or in combination (n = 5). The other patient with a severely hypoplastic aortic valve ring underwent the Ross procedure as a primary operation. Two operative deaths occurred. In both cases severe endocardial fibroelastosis was detected at autopsy. One late death 1 year after the operation resulted from progressive hypertrophic cardiomyopathy and pulmonary hypertension. The rest of the patients are doing well, without medications. Apart from trivial regurgitation in two patients, the pulmonary autograft is performing well.

Pulmonary autograft for aortic valve replacement in rheumatic disease: a caveat

Pulmonary autograft replacement of the aortic valve offers an attractive option in the younger patient with growth potential and long-term survival. In our institution between January 1990 and August 1994, 78 patients have undergone this procedure. The mean age was 18.6 +/- 7.36 years (range, 1 to 41 years). The etiology was rheumatic in 63 patients (80.7%). Aortic regurgitation was the predominant lesion in 60 patients (76.9%). Significant mitral regurgitation requiring operation was present in 22 patients (28.2%). All patients underwent pulmonary autograft replacement of the diseased aortic valve and the mitral valve was repaired in 22 patients. There were no hospital mortality, endocarditis, or thromboembolism in the series up to date. There have been two late non-cardiac deaths. Five patients (6.4%) required reoperation, one for mitral repair failure and four for autograft failure. Acute rheumatic valvulitis was demonstrated in one of the reoperated patients. Echocardiography of 68 patients followed up more than 2 months show progression of aortic regurgitation more than 2/4+ in 12 patients (15.4%). Four of these patients have been reoperated without mortality. In conclusion, although the Ross procedure remains a safe and attractive alternative in aortic valve operation, the progression of aortic regurgitation, especially in the younger patient with rheumatic etiology, remains a concern.

Aortic valve replacement with allograft/autograft: subcoronary versus intraluminal cylinder or root

From April 1990 to May 1994, 89 patients (median age, 42 years; range, 10 days to 66 years) underwent aortic valve or root replacement with allografts or autografts. Thirteen patients were less than 18 years old at the time of operation. Indication for aortic valve replacement was aortic stenosis (50 patients, 56%), small stenotic prosthesis (2 patients, 2%), aortic valve endocarditis (19 patients, 21%), isolated aortic regurgitation (17 patients, 19%), and type II truncus arteriosus (1 patient, 1%). The subcoronary implantation was used in 45 patients (group A), and implantation of an intraluminal cylinder (16 patients) or complete root replacement (28 patients) was performed in the remaining 44 patients (group B). The Ross procedure was performed in 22 patients. Intraoperative transesophageal echocardiography was used routinely. Five patients died in the early postoperative period (6%), 2 in group A and 3 in group B. Three other patients required immediate replacement of a failing graft by a mechanical prosthesis (1 in group A and 2 in group B). There has been no late death. All survivors remained in New York Heart Association functional class I and were free of thromboembolic complications. Endocarditis occurred in 2 patients, 1 year after operation. Both were successfully treated medically. Echocardiographic studies were obtained serially in every patient. Four patients, 2 in group A and 2 in group B underwent reoperation because of mild-to-moderate aortic regurgitation (rate of reoperation, 5%). Two valves were repaired and two were replaced by an allograft.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Pulmonary autograft aortic valve replacement. Early experience with the Ross procedure

Aortic valve replacement with a pulmonary autograft was performed in 24 patients between October 1993 and October 1994, at the All India Institute of Medical Sciences, New Delhi. There were 20 (83.3%) males and 4 (16.7%) females. Their ages ranged from 10 to 56 years (mean, 21.46 +/- 11.45 years). Associated procedures included 10 mitral valve procedures (4 open commissurotomies, 5 mitral valve repairs, and 1 homograft mitral valve replacement) and 1 tricuspid valve repair. There were 4 (16.7%) early deaths, 3 of which were due to bleeding or its sequelae and 1 due to septicemia. There were no late deaths. Follow-up ranged from 1 to 13 months (mean, 198.3 +/- 111.1 days). Nineteen (95%) patients are in New York Heart Association functional class I, and 1 patient (5%) is in class II, due to poor left ventricular function. Only 1 patient showed grade 2/4 aortic regurgitation on follow-up examinations, and none has shown progression of aortic regurgitation. Our early results with the pulmonary autograft are encouraging; however, long-term evaluation is needed.

Small aortic root in childhood: surgical options

Aortic valve replacement in the pediatric population is complicated by the often complex nature of the left ventricular outflow tract obstruction. Techniques to enlarge the annulus frequently are necessary. From 1977 to 1991, 32 children underwent an annular enlargement procedure at The Hospital for Sick Children, Toronto. During this same era, 110 children underwent a total of 138 aortic valve replacements. Eleven had the annulus enlarged with a posterior patch technique and implantation of a valve (mechanical 8, porcine heterograft 2, homograft 1) ranging from 20 to 25 mm in diameter. Twenty-two children had an anterior annular enlargement (aortoventriculoplasty) and aortic valve replacement with a valve (mechanical 8, porcine 2, homograft 12) 12 to 27 mm in diameter. One child had a posterior patch enlargement performed, followed by a second operation involving anterior annular enlargement. There was one early death in the posterior annuloplasty group and one late death due to failure of a bioprosthetic valve. There were five hospital deaths in the anterior annuloplasty group (22%; 70% confidence interval [CI], 14% to 32%) and two late deaths. Actuarial survival for the 32 children was 78% (70% CI, 70% to 86%) at 5 years and 65% (70% CI, 48% to 82%) at 10 years after repair. Younger children (age less than 1 year) had a significantly worse survival at 5 years (33%; 70% CI, 14% to 52%) than older children (88%; 70% CI, 82% to 95%). The survivors are well, and no reoperations have been necessary because of the children's outgrowing their valve.

Homograft replacement of the aortic valve and root as a functional unit

Homograft replacement of the aortic valve has inherent advantages for the patient in terms of decreased incidence of thromboembolism, endocarditis, and anticoagulation-related complications. Limitations in its use stem from a significant incidence of postoperative aortic regurgitation, related to difficulty with consistent commissural and sinotubular geometry when inserted in the subcoronary position. To minimize this complication, we used a homograft as a functional unit in 71 patients between 1986 and May 1993, either as a root replacement (n = 58) or as an intraaortic inclusion cylinder (n = 13). There were 4 pulmonary and 67 aortic homografts. Mean age of the 16 female and 55 male patients was 42 +/- 19 years (range, 0.6 to 84 years). Thirty patients had predominantly aortic regurgitation, 19 aortic stenosis, 18 mixed aortic valve disease, and 4 primary aneurysmal disease. Eighteen (25.4%) had infective endocarditis. Thirty-five patients (49%) had a previous operation on the aortic valve. Hospital mortality was 14.1% (10/71), 0% for inclusion cylinders and 17.2% (10/58) for root replacements (p = not significant). Recent follow-up was obtained in all hospital survivors. Mean follow-up period was 35 months (range, 1 to 81 months). There were six late deaths, 1/13 for inclusion cylinders and 5/48 for root replacements. Actuarial survival at 5 years was 74.9% +/- 5.6%. Reoperation was required in 3 patients (all with root replacements), 1 for postoperative endocarditis, 1 for left coronary ostial obstruction, and 1 for late onset of aortic dilatation and regurgitation (pulmonary homograft used as a root replacement). Two patients currently have asymptomatic greater than 2/4 aortic regurgitation. Freedom from significant aortic regurgitation was 88% +/- 7% at 6-year follow-up. More consistent maintenance of the sinotubular and commissural geometry of the aortic homograft may be achieved with the root replacement or the inclusion cylinder techniques. This may reduce the incidence of postoperative aortic regurgitation and further benefit the patient by reducing the need for reoperation in the future.

Pulmonary autograft in children: realized growth potential

Pulmonary autograft replacement of the aortic valve has the potential to remain viable and grow in proportion to the somatic growth of the child. Changes in aortic annulus and sinotubular dimensions were compared early and late postoperatively, and related to normal. Eighty-six children, 0.9 to 21 years, were operated on between 1986 and 1993: 42 had a root replacement, 24 an inclusion cylinder, and 20 a scalloped subcoronary implant. Actuarial survival at 7 years was 96.5% +/- 2.0%. Freedom from reoperation for the pulmonary autograft or the homograft reconstruction of the right ventricular outflow tract was 92% +/- 4%. Freedom from reoperation on the autograft in root replacements was 96% +/- 4%, in the inclusion cylinder was 100%, and in the scalloped subcoronary was 90% +/- 7% (not significant). Aortic annulus and sinotubular junction diameters were compared with normal values predicted by body surface area. In 22 intraaortic implants, early and late postoperative annulus diameter mean Z values are in the normal range. In the 23 root replacements, early annulus diameter was within the normal range, but late Z values were larger than normal (p < 0.02). Intraaortic implant annulus diameter increased proportionally to somatic growth, but the sinotubular junction, which was small, remained small but increased toward normal. In the root replacements, the annulus increased in diameter and became dilated. The sinotubular junction, which was small early, increased and was within the normal range late. Lower operative risk and valve durability without failure suggest improved results with inclusion cylinder technique.(ABSTRACT TRUNCATED AT 250 WORDS)

Ventricular function after the arterial switch operation for transposition of the great arteries

The theoretical advantages of anatomical repair have resulted in the widespread use of the arterial switch operation for transposition of the great arteries. However, preservation of systemic ventricular performance and late functional results have not been well documented. To evaluate late postoperative ventricular function, we reviewed 53 consecutive patients undergoing arterial switch operation for transposition of the great arteries with or without a ventricular septal defect over the 8-year period from March 1985 to 1993. Forty-two patients had simple transposition of the great arteries and 11 patients had associated ventricular septal defects that were closed at operation. Mean age at operation was 1.8 months (range, 1 day to 36 months), and mean patient weight was 3.8 kg (range, 1.8 to 15.6 kg). All but 8 patients were neonates. There were six operative deaths (11.3%, 6/53) and two late deaths during a median follow-up of 23 months (range, 0.1 to 99.5 months). Actuarial survival at 8 years was 83% +/- 6%. Left ventricular outflow tract obstruction has not been identified, and 9 patients (20%, 9/45) have right ventricular outflow tract gradients exceeding 20 mm Hg, 3 of whom have required reoperation. Eighteen patients have mild neo-aortic valve regurgitation. All survivors are currently in New York Heart Association class I, and are in sinus rhythm. Systolic left ventricular function is well preserved with ejection fractions greater than 0.60 in all survivors followed up for more than 4 months (41 patients). Left ventricular end-diastolic volume index is elevated in only 1 patient, a patient who had pulmonary artery banding as a neonate.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary autograft replacement of the aortic valve in the potential parent

Aortic valve replacement in the child and young adult is often delayed, and multiple operations or invasive procedures are performed to avoid valve replacements. Prosthetic valves, bioprosthetic valves, or allograft valves have been associated with significant complications or early failure and have been a disappointing solution for the patient requiring aortic valve replacement. The pulmonary autograft replacement (PAR) of the aortic valve in children has been shown to be safe and effective with a low incidence of late valve dysfunction. The absence of thromboembolism, the avoidance of anticoagulants, and its viability with the potential for growth and repair strongly support its use for the potential parent, patients of age 35 or less. The experience with 112 patients, 32 females and 80 males, ages 1.5 to 35 years (average 16.1) are reviewed. Twenty-four had aortic insufficiency, 34 had aortic stenosis, and 54 had both aortic stenosis and insufficiency. Actuarial survival was 95.4% +/- 2.0% at 7 years and freedom from reoperation or significant aortic insufficiency of the autograft valve was 92.7% +/- 3.7%. Freedom from all valve related complications of the autograft valve and the homograft replacement of the pulmonary valve was 90.0% +/- 4.0%. Reoperation for the autograft valve was related to limited experience in one, leaflet prolapse and adherence to a VSD patch in one, associated lupus erythematosus in one, and annular and sinotubular dilatation in one. Reoperation of the homograft valve in two patients was secondary to early homograft stenosis, probably due to rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

Replacement of the aortic root with a pulmonary autograft in children and young adults with aortic-valve disease

BACKGROUND

The optimal substitute for severely diseased aortic valves in children and young adults is unknown. The use of a mechanical prosthesis requires permanent treatment of the patient with anticoagulants and is associated with thromboembolic and hemorrhagic complications. Aortic-valve allografts and porcine bioprostheses, which do not necessitate anticoagulant therapy, may deteriorate and have limited durability.

METHODS

We therefore evaluated the use of the autologous pulmonary valve (i.e., the patient's own pulmonary valve) and the adjacent pulmonary artery as a replacement for the aortic valve and aortic sinuses in 33 patients. Five of the patients were from 8 to 16 years of age, and 28 were from 20 to 47 years of age. The pulmonary valve and the main pulmonary artery were used to replace the diseased aortic valve and the adjacent aorta. The coronary arteries were detached from the aorta and implanted into the pulmonary artery. The pulmonary valve and artery were replaced with a cryopreserved pulmonary allograft.

RESULTS

There were no deaths during follow-up of up to 48 months (mean, 21 months). There were no episodes of infective endocarditis, and no reoperations on the aortic root were necessary. Also, there was no evidence on echocardiography of progressive dilatation of the autografts. With color-flow Doppler imaging, 22 patients were found to have only trivial regurgitation or none, 9 patients to have mild regurgitation, and no patients to have moderate or severe regurgitation across the autograft at the most recent follow-up visit. The mean peak velocity of flow across the autograft was 1.3 m per second (upper limit of normal, 1.8), indicating the absence of stenosis. One patient required reoperation for stenosis of the pulmonary allograft.

CONCLUSIONS

Although the pulmonary-autograft procedure is more complex than simple aortic-valve replacement, it has been safely applied in selected patients, including young adults. Intermediate follow-up indicates satisfactory function of the autografts, with no dilatation or progressive valvular regurgitation. Pulmonary-root autografts may thus be the best available substitute for diseased aortic valves in children and young adults.