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

The Ross, Konno, and Ross-Konno operations for congenital left ventricular outflow tract abnormalities

Operations for left ventricular outflow tract abnormalities are centred on hemodynamic conditions that relate to subvalvar stenosis, valvar stenosis/regurgitation, aortic annular hypoplasia, and supravalvar aortic stenosis. Operative interventions over the years have evolved because the intervening outcomes proved to be unsatisfactory. The resection for subvalvar aortic stenosis has progressed from a fibrous "membrane" resection to a more extensive fibromuscular resection. Operative solutions for valvar aortic stenosis and regurgitation have resulted in operative interventions that depend on simple commissurotomy, leaflet extensions, prosthetic mechanical valve replacement, biologic valve replacement, including the pulmonary autograft, and operations to treat aortic annular stenosis. Although there are enthusiastic proponents for all of these strategies, the fact remains that none have proven to be curative; patients can expect to undergo further procedures during their lifetimes. The short- and mid-term solutions to these left ventricular outflow tract abnormalities have improved based on operations that have been attended by increasing operative complexity. The purpose of this review is to chronicle the operative steps of the Ross operation, the Konno-Rastan operation, the modified Konno operation, the Ross-Konno operation, and the modified Ross-Konno operation.

Neonatal aortic stenosis

Neonatal aortic stenosis is a complex and heterogeneous condition, defined as left ventricular outflow tract obstruction at valvular level, presenting and often requiring treatment in the first month of life. Initial presentation may be catastrophic, necessitating hemodynamic, respiratory and metabolic resuscitation. Subsequent management is focused on maintaining systemic blood flow, either via a univentricular Norwood palliation or a biventricular route, in which the effective aortic valve area is increased by balloon dilation or surgical valvotomy. In infants with aortic annular hypoplasia but adequately sized left ventricle, the Ross-Konno procedure is also an attractive option. Outcomes after biventricular management have improved in recent years as a consequence of better patient selection, perioperative management and advances in catheter technology. Exciting new developments are likely to significantly modify the natural history of this disorder, including fetal intervention for the salvage of the hypoplastic left ventricle; 3D echocardiography providing better definition of valve morphology and aiding patient selection for a surgical or catheter-based intervention; and new transcutaneous approaches, such as duel beam echo, to perforate the valve.

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.

Critical aortic stenosis in the neonate: a multi-institutional study of management, outcomes, and risk factors. Congenital Heart Surgeons Society

OBJECTIVES

We sought to determine factors that would predict whether a biventricular repair or Norwood procedure pathway would give the best survival in neonates with critical aortic stenosis.

METHODS

Survival and risk factors were determined with parametric time-dependent event analysis for patients undergoing either the Norwood procedure or biventricular repair, and predicted optimal pathway and survival benefit were derived from multivariable linear regression.

RESULTS

From 1994 to 2000, 320 neonates with critical left ventricular outflow obstruction were entered into a prospective multi-institutional study. Patients who died without intervention (n = 19) and those with primary cardiac transplantation (n = 6) were excluded. An initial intended biventricular repair pathway was indicated in 116 patients, with survival of 70% at 5 years. An initial Norwood procedure was performed in 179 patients, with survival of 60% at 5 years. Using predictions from separate multivariable hazard models for survival with each of the 2 pathways, we determined predicted optimal pathway and survival benefit for each patient. Significant independent factors associated with greater survival benefit for the Norwood procedure versus biventricular repair included younger age at entry, lower z-score of the aortic valve and left ventricular length, higher grade of endocardial fibroelastosis, absence of important tricuspid regurgitation, and larger ascending aorta. Predicted survival benefit favored the Norwood procedure in 50% of patients who had biventricular repair, and it favored biventricular repair in 20% of patients who had the Norwood procedure.

CONCLUSIONS

Morphologic and functional factors can be used to predict optimal pathway and survival benefit in neonates with critical left ventricular outflow obstruction.

[Clinical guidelines of the Spanish Society of Cardiology for the most frequent congenital cardiopathies]

The use of diagnostic and therapeutic techniques is very important to ensure optimum, effective treatment in patients with heart disease to thereby obtain an adequate cost-benefit relationship. The aim of establishing guidelines for the evaluation and management is to achieve this relationship, but these guidelines are difficult to establish in pediatric cardiology despite 50 years of experience in this field. At present a large group of patients may benefit from these guidelines due to the improvement in the diagnostic techniques and better treatment results in congenital heart disease in the newborn. Protocols have been established in some groups and in others in which this is not possible, descriptive analysis and therapeutic schedules have been determined.

Increase in size of the pulmonary autograft after the Ross operation in children: growth or dilation?

OBJECTIVE

We sought to assess growth properties of the pulmonary autograft after the Ross operation in children.

METHODS

Eight infants with critical aortic stenosis who underwent the Ross operation early in life (median age, 6.4 months) were followed up regarding the possible growth of the autograft. The pulmonary autograft was measured repeatedly by echocardiography during the follow-up, ranging from 6 months to 7 years (median, 5.2 years). Twelve normal children who served as control subjects were similarly followed from 3.9 to 5.8 years (median, 4.9 years).

RESULTS

Somatic growth during the follow-up period was significant and was reflected in a doubling of the body surface area, which increased from 0.33 +/- 0.14 m(2) to 0.74 +/- 0.21 m(2). The proximal part of the autograft increased from 13.6 +/- 3.6 mm to 23.3 +/- 3.7 mm (mean +/- SD) and the distal part from 10.5 +/- 2.5 mm to 15.9 +/- 2.8 mm. Growth pattern of the autograft was analyzed by relating measured diameters to predicted normal diameters (ie, Z values). During the first year after the operation, the mean Z value of the proximal autograft increased from 0.2 to 2.2, indicating a more rapid increase than the predicted increase and was also significantly higher than that of the control group (P =.01). After the first year, Z-value changes in patients and control subjects were very similar.

CONCLUSIONS

We thus conclude that the pulmonary autograft in the aortic position after the Ross operation does increase in size and that the pattern of this increase is suggestive of passive dilation in the early postoperative period, followed by normal active growth.

Semilunar valve switch procedure: autotransplantation of the native aortic valve to the pulmonary position in the Ross procedure

BACKGROUND

The Ross procedure has gained wide acceptance in young patients with aortic valve disease. The durability of the pulmonary autograft in the aortic position has been proved, with up to 24 years of follow-up. The homograft pulmonary valve, however, has limited longevity. To circumvent this problem we harvested, repaired, and reimplanted the native aortic valve with intact commissures in the pulmonary position in 13 patients undergoing the Ross procedure for aortic insufficiency.

METHODS

The cause of aortic insufficiency was rheumatic in 6 patients, congenital in 4, post-aortic valvotomy in 2, and bacterial endocarditis in 1. Patient age ranged from 5 to 45 years (mean, 17+/-9 years). Root replacement technique with coronary artery reimplantation was used. In the first 4 patients, the native aortic valve was sutured into the right ventricular outflow tract, and a polytetrafluorethylene patch was used to reconstruct the main pulmonary artery. In the last 9 patients, the aortic valve and polytetrafluorethylene patch were made into a conduit by another surgeon while the left-sided reconstruction was performed.

RESULTS

All patients had marked reduction of left ventricular dilation and good function of the reimplanted native aortic valve, with up to 50 months of follow-up (mean, 29.9+/-14.2 months; range, 12 to 50 months). Two patients died 15 and 26 days, respectively, of a false aneurysm rupture at the distal aortic anastomosis. In the remaining 11 patients, 9 (82%) had mild or absent, and 2 (18%) had mild to moderate, neoaortic valve regurgitation. Similarly, 9 patients (82%) had mild or absent, and 2 (18%) had mild to moderate, neopulmonary valve regurgitation. Mild neopulmonary valve stenosis was present in 6 patients (54%) (mean gradient, 29+/-4 mm Hg; range, 25 to 35 mm Hg). All surviving patients are in functional New York Heart Association functional class I.

CONCLUSIONS

We conclude that use of the native aortic valve with the Ross procedure makes the procedure attractive and potentially curative. The diseased aortic valve works well in the pulmonary position because of lower pressure and resistance. The valve leaflets should remain viable and grow in both the pulmonary and aortic positions because they derive nutrition directly from the blood.

Congenital heart disease: six decades of progress

Congenital heart malformations occur in approximately 1 in 100 live births. Since Robert Gross successfully ligated a persistent ductus arteriosus 60 years ago, there has been enormous progress in the surgical management of even the most complex lesions. More recently, the interventional cardiologist armed with balloons, stents, coils, umbrellas, and laser beams is providing an alternative to surgery for many lesions. Echocardiography combined with Doppler studies is now the most informative diagnostic modality, and its usefulness is being expanded by transesophageal studies. Magnetic resonance imaging is helpful for some lesions not well visualized on echo. Some complex lesions continue to challenge caregivers, especially the hypoplastic left heart syndrome and several variants of pulmonary atresia. Neurological complications in patients with congenital heart disease are not uncommon and are the main theme of this issue.

[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.

Can echocardiography predict the presence or absence of endocardial fibroelastosis in infants <1 year of age with left ventricular outflow obstruction?

This study assesses the use of echocardiography in detecting endocardial fibroelastosis in 32 infants with obstructive left-sided lesions. The data demonstrate that neither endocardial echo-brightness nor geometric variables of the left ventricle allow for accurate prediction of the presence of endocardial fibroelastosis.

Disproportionate enlargement of the pulmonary autograft in the aortic position in the growing pig

PURPOSE

This study was aimed to demonstrate growth in the pulmonary autograft after transplantation to the aortic position.

METHODS AND MATERIALS

In 20 piglets (weight 25.4 +/- 3.5 kg) (mean +/- standard deviation) a Ross operation was performed and in five piglets (weight 9.3 +/- 0.7 kg) (mean +/- standard deviation) the ascending aorta was replaced with a valveless pulmonary autograft. Animals were allowed to grow as much as possible. Postmortem explanted autografts were studied by direct measurements of the valve cusps in the Ross group and of the wall segments in the valveless autograft group. Measurements of the first group were compared with the values of a separate control group, and values of the second group were compared with values of samples taken at operation.

RESULTS

In the Ross group, cuspal weight, height, and width increased significantly by comparison with body weight (p < or = 0.003). The rate of increase did not differ significantly from that of the control group with a native pulmonary valve. However, there was a rapid adaptation of the autograft valves resulting in a significantly higher mean cuspal weight, height, and width. In the valveless autograft group, wall circumference, thickness, and height increased significantly (p < or = 0.001). The circumference increased significantly more than that of the native pulmonary wall. Compared with the native aortic wall, the pulmonary autograft media showed retained pulmonary architecture on microscopic study.

CONCLUSION

These data suggest that the dimensional increase of the pulmonary autograft in the aortic position in the growing pig is determined by growth and dilatation, that the valve mass increases more than that of the native pulmonary valve, and that the characteristic pulmonary microscopic architecture is retained.

Pulmonary artery augmentation with autologous aortic tissue

OBJECTIVE

To assess durability and viability of autologous aortic tissue used to augment severe branch pulmonary artery stenosis with a novice surgical technique.

PATIENTS AND METHODS

Seven patients underwent corrective surgery for complex cyanotic congenital heart disease. Their age ranged from 3-6 years, and their weight 11-17.4 kg. All had concomitant branch pulmonary artery stenosis repaired utilizing an autologous patch, harvested from the patient's own aorta by excising a ring and opening it to form the patch. The aorta is reconstructed directly by end to end anastomosis.

RESULTS

One patient died in hospital. Another patient died at 18 months at home. The surviving five patients have remained well in the follow up period of mean 31 months (range 10-52). All patients were restudied by follow up echocardiography and remain with no evidence of the aortic autograft tissue calcification or stenosis. The reconstructed aorta showed no stenosis at the site of anastomosis.

CONCLUSION

The intermediate term results of this novice surgical technique appear encouraging and justify the technique. However, longer follow up will be required to confirm the continued growth of this patch material.