[Place of the Ross procedure (pulmonary autograft) in aortic valve surgery]

The pulmonary autograft operation consists of an aortic replacement using the autologous pulmonary valve. The pulmonary valve is substituted by a cryopreserved pulmonary homograft. This operation is in fact a delicate double valve replacement whose benefits are linked to the viability of the new aortic substitute. The pulmonary autograft has superb hemodynamic features and very low thrombogenicity. The report of a selected observation offers the occasion of defining the current indications of this operation in aortic valve surgery.

[The correction of pulmonary insufficiency with a cryopreserved homograft: an optimal solution to a postoperative problem not rare]

Although the results of surgical repair for congenital pulmonary stenosis are generally good, some patients develop progressive symptoms related to pulmonary regurgitation and right ventricular dilation. Pulmonary homograft implantation may have a beneficial effect on these symptoms, due to a reduction in the volume overload of the right ventricle and hemodynamic improvement. We describe our experience of one patient with severe pulmonary regurgitation following pulmonary valvotomy performed with the Brock technique during childhood because of pulmonary valve stenosis. The patient was admitted to our Institution because of dyspnea on exertion (NYHA functional class II-III) and paroxysmal episodes of supraventricular arrhythmias. Echocardiography showed severe pulmonary regurgitation, an important right ventricular dilation associated with severe tricuspid insufficiency and a patent foramen ovale without any significant shunts. Surgical repair was performed through a median sternotomy with cardiopulmonary bypass and moderate hypothermia. The right ventricular infundibulum was opened and a cryopreserved pulmonary homograft was implanted with continuous sutures. De Vega annuloplasty was performed on the tricuspid valve and the patent foramen ovale was closed with a running suture. Postoperative course was uneventful and the patient was discharged on the seventh postoperative day. Three months after surgery the patient is asymptomatic and echocardiographic evaluation shows no evidence of pulmonary or tricuspid regurgitation, a decrease in right ventricular dilation and a significant improvement in biventricular systolic and diastolic function. In conclusion, pulmonary regurgitation after surgical valvotomy can be treated with the implantation of a cryopreserved pulmonary homograft with satisfactory results. It would appear advisable to perform surgical repair of concomitant right heart anomalies, such as secondary tricuspid insufficiency, to obtain both a decrease in right ventricular overload and a regression of its preoperative dilation.

Results of the Ross operation in rheumatic versus non-rheumatic aortic valve disease

BACKGROUND AND AIM OF THE STUDY

A total of 213 patients underwent the Ross operation at our institution between January 1990 and January 1999. Outcome was assessed in rheumatic (RH) patients and compared with that in patients with other etiology (non-RH).

METHODS

After exclusion of 69 patients with a follow up of <18 months, the study group comprised 144 patients (119 RH, 25 non-RH). Patients were studied clinically and by echo-Doppler cardiography preoperatively, within 2 months and 6-8 months after surgery, and yearly afterwards. Preoperative assessment included age, gender, body surface area (BSA), type of aortic valve lesion and additional valve disease, left and right ventricular outflow tract (LVOT, RVOT) dimensions, and left ventricular (LV) size, function and mass. Postoperatively, patients were studied for presence and severity of autograft regurgitation, mitral regurgitation, LV size, function and mass, and incidence and timing of reoperation.

RESULTS

On average, RH patients were older and had higher BSA, more aortic regurgitation than stenosis, more additional mitral valve disease (mostly regurgitation), larger LV size and poorer LV function. Mitral valve repair was performed in 24% of RH patients versus 0% of non-RH patients. Postoperatively, differences in LV size, function and mass remained present, but diminished during follow up. The autograft reoperation incidence was 22% (26/119) in RH patients versus 8% (2/25) in non-RH patients (p = NS). Preoperative predictors for reoperation in the RH group were severe concomitant mitral regurgitation (MR), followed by male gender and large indexed LVOT (all p<0.001 by discriminant analysis).

CONCLUSION

Marked differences were present in patient characteristics between rheumatic and nonrheumatic patients who underwent the Ross operation. Rheumatic patients had a higher incidence of autograft reoperation. Severe concomitant MR was the most important predictor for reoperation in rheumatic patients.

Bentall operation with valved homograft conduit

Lesions of the ascending aorta associated with aortic valve disease are usually treated by implanting a prosthetic valved conduit (Bentall procedure). In this report, we present our experience in which a valved homograft conduit was used for the procedure. Six patients underwent a Bentall procedure with the use of a cryopreserved valved homograft conduit. Two of the patients had annuloaortic ectasia, 2 had Marfan syndrome, and 1 had an atherosclerotic aneurysm of the aorta. One patient had severe aortic stenosis due to a bicuspid aortic valve, along with an aneurysm and localized dissection of the ascending aorta. In all of the patients, the aortic annulus was substantially dilated, with accompanying moderate-to-severe aortic regurgitation. A standard procedure was performed with moderate hypothermia, cardiopulmonary bypass, and aortic and bicaval cannulation. The ascending aorta and the aortic valve were replaced with a cryopreserved valved homograft conduit (aortic in 5 patients and pulmonary in 1). The native coronary ostia were anastomosed directly to the homograft. Echocardiography, which was performed intraoperatively, before discharge from the hospital, and at follow-up visits (1 to 36 months), revealed good valve function without dilatation of the homograft conduits. There was 1 late death due to Aspergillus fumigatus endocarditis, 6 months postoperatively. In 1 patient, magnetic resonance imaging performed at 24 months revealed normal caliber of the homograft conduit. We conclude that the Bentall procedure can be performed, safely and with excellent results, using cryopreserved homograft conduits.

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.

Siena's experience with pulmonary autograft operations: clinical and echocardiographic follow-up

As there is no perfect aortic valve substitute, there is a need to find out which one is the best option to replace the diseased aortic valve. Any type of mechanical or biological stented device has a residual gradient and does not reproduce the extremely sophisticated normal aortic valve function. This may influence the short- and long-term outcome, especially in dilated and poorly contracting left ventricles which do not tolerate even a mild stenosis. Thus, the potentially ideal valve to replace the aortic valve is either an aortic valve (aortic homograft) or a pulmonary autograft in aortic position. These grafts are also less subject to endocarditis. It has been demonstrated that pulmonary autografts can grow when implanted in children and as they remain viable, they maintain their dynamic behavior and possibly the internal innervation of the cusps. Unfortunately, pulmonary autograft surgery is more demanding and lasts longer, which may increase the risk of the operation. In addition, the exact indications and applications of the operation, particularly in patients with poor left ventricles or additional lesions, have not been clearly defined. Here we report our experience with this technique in 11 patients with severe aortic valve disease, including those with poor left ventricle function and/or associated disease. We describe our short- and medium-term follow-up, which shows optimal left ventricle recovery with no perioperative or postoperative complications, thus supporting a wider application of the operation.

Ross procedure. Inserting the autograft using a fully supported root replacement method; techniques and results

BACKGROUND AND AIM OF THE STUDY

The root replacement (RR) method for insertion of the pulmonary autograft (PA) has resulted in improved immediate aortic valve competence. However, the unsupported pulmonary artery wall is thinner, more elastic, and thus more prone to dilatation than the normal aortic root. This might predispose to late aortic regurgitation (AR) due to splaying of the aortic commissures, similar to the mechanism of AR in Marfan's syndrome.

METHODS

A fully supported root replacement (FSRR) method was designed and implemented in 78 patients, with preservation of the aortic root and proximal ascending aortic remnant fully to surround and support the PA root. Additional aortic annulus reduction was performed in 29 patients, and adjustment of the sinotubular diameter in 27.

RESULTS

Seventy-eight patients were analyzed with sequential Doppler echocardiography. The maximal neoaortic sinus diameter remained constant for up to three years after surgery (mean 34.3 +/- 4.0 mm) compared with before surgery (35.2 +/- 4.0 mm). There was one early death, no late deaths or reoperations, and at last follow up AR was nil/trivial in 72% of patients, mild in 27% and moderate in 1%. There was no progression of AR over four years' follow up. By comparison, four patients previously underwent unsupported RR for insertion of the PA; in these patients, mean neoaortic sinus diameter increased significantly from 31 +/- 6 mm to 41 +/- 3 mm at three years after surgery (p = 0.005).

CONCLUSIONS

Insertion of the PA using a FSRR method prevents dilatation of the neoaortic sinuses and sinotubular junction without need for prosthetic material, and provides similar results to conventional RR with regard to aortic valve competence. Retaining the advantages of RR in this manner and maintaining aortic root size may prove valuable in the longer term.

The Ross procedure in children under ten years of age

BACKGROUND AND AIMS OF THE STUDY

The potential advantages of the Ross procedure in children under 10 years of age have yet to be validated. Concerns remain regarding progressive dilatation of the pulmonary autograft and potential homograft stenosis. We present our experience in this age population.

METHODS

A retrospective analysis of aortic root replacement using the Ross procedure in 11 young children (nine males, two females; median age 84 months; range 3 months to 10 years) between January 1996 and January 1999 was performed jointly in two pediatric surgical centers.

RESULTS

There were no operative deaths. Mean hospital stay was 12 +/- 4 days, and mean follow up 14.5 +/- 8 months. The event-free survival (death, reoperation, endocarditis, arrhythmia) was 100%. Currently, nine children are in NYHA functional class I, and two in class II. The autograft and homograft were evaluated by serial echocardiography. There was no sign of progressive dilatation of the autograft. Aortic regurgitation was trivial in four children and mild in seven. No growth of the autograft was noted; this was consistent with minimal somatic growth. Homograft peak gradients remained low during the follow up.

CONCLUSIONS

Although the pulmonary autograft procedure is more complex than other types of aortic valve replacement, it can be safely applied in children. Early follow up indicates satisfactory performance of the autograft. If dilatation will not occur, pulmonary root autograft may be an attractive substitute for diseased aortic valves in children.

Aneurysms complicating pulmonary autograft procedure for aortic valve replacement

Aneurysm formation in the left ventricular outflow tract related to the proximal end of the pulmonary autograft after the Ross procedure was present in 2 patients. Both occurred late after operation and were associated with prolapse of a leaflet of the autograft and significant regurgitation. Both were repaired with no immediate complications. There was no evidence of infection at time of operation. The probable mechanisms underlying this complication and the possibilities of avoiding it are discussed.

Critical analysis of the Ross procedure: do its problems justify wider application?

The Ross procedure has shown superior hemodynamic results in young patients with aortic root pathology. Wider application of the procedure is restricted by its technical complexity and potential associated problems. The mortality/morbidity associated with 130 consecutive patients who have had the Ross procedure using the root replacement implantation technique between October 29, 1990, and October 8, 1998 is summarized. New York Heart Association (NYHA) preoperatively was class I, 23.5%; class II, 64.7%; and class III, 11.8%; mean age was 36 years (range 3 to 67 years). Men accounted for 73.8% and women 26.2% of the series. Preoperative diagnosis was congenital, 80.7%; rheumatic, 5.3%; failed prosthesis, 7.0%; degenerative, 2.6%; and endocarditis, 4.4% with preoperative aortic insufficiency (AI) 7.9% 1+, 19.8% 2+, 29.7% 3+, and 42.6% 4+, respectively. At operation mean cross-clamp time was 201 minutes (range 102 to 280 minutes). Patient follow-up was 99.2% (1 patient lost to follow-up), and 94.4% were NYHA class I at follow-up and 5.6% class II. Postoperative AI was 0 to 1 + in 93.6% and 2+ or greater in 6.4%. Mean time to patient follow-up was 436 days (range, 20 days to 2,878 days). Thirty-day mortality rate was 1.5%; one patient died of mediastinal bleeding, and one from complications of acute pancreatitis. There was no late mortality. Early autograft explant occurred in one patient secondary to iatrogenic injury to the pulmonary autograft at the time of harvesting, and one late explant occurred secondary to proximal suture line dehiscence. Late autograft repair occurred in one patient secondary to a false aneurysm along the proximal suture line; one patient was reoperated for left main coronary stenosis relative to iatrogenic injury at the time of the procedure. Right ventricular outflow tract replacement has occurred in two patients. Postoperative morbidity and mortality for the Ross procedure, as shown in this series, remains low and supports broader application of the procedure.

Risk factors for coronary complications after stentless aortic root replacement

Coronary complications after aortic root replacement (ARR) with pulmonary autografts have been reported to be more common than with other stentless biological conduits (homografts, xenografts). To verify this hypothesis, results with 84 consecutive patients having stentless ARR between January 1992 and January 1999 were reviewed. Fifty patients had autograft (Group 1) and 34 either homograft or xenograft (Group 2) ARR. Comparison of age (27+/-9 vs. 38+/-22 years, P = ns), prevalence of male sex (86% vs. 79%, P = ns), aortic root disease (30% vs. 44%, P = ns), congenital coronary anomalies (10% vs. 3%, P = ns), prior aortic procedure (16% vs. 15%), and need for associated procedures (26% vs. 24%, P = ns), did not disclose significant differences. Bicuspid aortic valve was more prevalent in Group 1 (56% vs. 9%, P = .001). Mean aortic crossclamp (154+/-28 vs. 120+/-24 minutes, P = .05) and bypass (216+/-30 vs. 192+/-58 minutes, P = .05) times were longer in Group 1. Early mortality was comparable (2% vs. 3%, P = ns) and caused by right ventricular ischemia in both groups. Overall prevalence of coronary complications was higher in Group 1 (10% vs. 3%, P = .04), all resulting in right heart ischemia. Intraoperative partial takedown of repair in 5 Group 1 patients, associated with CABG in 1, resulted in prompt resolution of myocardial ischemia in 4 (80%) and prolonged in 1, which ultimately died as a result of sepsis. Recovery was prompt in all 4 patients (mean ICU stay 35+/-28 hours) with no metabolic or echocardiographic evidence of myocardial infarction. At discharge echocardiography, satisfactory biventricular kinetics was found in all patients. Analysis of preoperative variables showed bicuspid aortic valve (83% vs. 33%, P = .01) and coronary anomalies (67% vs. 3%, P = .001) to be more prevalent in patients suffering from coronary complications. Stentless ARR is a safe procedure with low operative mortality, regardless of the type of biological conduit. Autograft ARR may be at greater risk of right ventricular ischemia in patients with bicuspid aortic valve and coronary anomalies. An aggressive intraoperative approach including partial takedown of repair may limit the morbidity of coronary complications.

Aortic root replacement with the pulmonary autograft: an invariably competent aortic valve?

BACKGROUND

Pulmonary autograft aortic root replacement was used in adults. Risk factors for aortic regurgitation (AR), and for pulmonary allograft valve stenosis are identified.

METHODS

From February 1991 through April 1998, 80 adults (mean age 34.4 years) underwent pulmonary autograft aortic root replacement. Primary diagnosis was AR in 43 (53.7%) patients, aortic stenosis in 13 (16.3%) and mixed disease in 24 (30%) patients. A root reinforcement ring was used in 32 (40%) patients.

RESULTS

There was no hospital mortality. Estimated patient survival is 100% at 7 years. A total of 3 patients underwent reoperation: 2 on the autograft for severe AR, 1 for pulmonary allograft stenosis. Freedom from reoperation on the autograft is 96.7 +/- 2.4% at 7 years. Multivariate analysis indicated bicuspid aortic valve disease as an incremental risk factor for AR at discharge (p = 0.036, odds 3.5). Univariate analysis identified operation for pure AR as risk factor for AR during follow-up (p = 0.041). Mild AR or more increased from 2.5% at discharge to 11.3% during follow-up (p = 0.008). Progression of AR was limited by the use of a reinforcement root ring (p = 0.031). Freedom from mild AR or more in patients with and without a reinforcement root ring was 100% and 72.9 +/- 9.3% respectively, at 5 years (p = 0.119). Pulmonary allograft stenosis occurred in 15 (22.5%) patients. Multivariate analysis revealed that large sized pulmonary allografts were less prone to stenosis (p = 0.048, odds 0.13).

CONCLUSIONS

Pulmonary autograft root replacement can be performed with few complications. During follow-up, a significant increase in mild AR or more is observed. The use of a reinforcement root ring is effective in preventing progression of AR.

Histologic abnormalities of the ascending aorta and pulmonary trunk in patients with bicuspid aortic valve disease: clinical relevance to the ross procedure

OBJECTIVE

Bicuspid aortic valve disease is often associated with dilation of the aortic root and ascending aorta. This study examines the histologic features of the ascending aorta and main pulmonary artery of patients with and without aortic valve disease.

METHODS

Samples from ascending aorta and main pulmonary artery were obtained at the time of the operation from 20 patients with bicuspid aortic valve and 11 patients with tricuspid aortic valve disease. In addition, samples were also obtained from autopsy cases with normal aortic valve. The histologic changes were graded from 1 to 3 according to severity of degenerative changes.

RESULTS

In the ascending aorta, the severity of cystic medial necrosis (P =.001), elastic fragmentation (P =.002), and changes in the smooth muscle cell orientation (P =.002) were significantly more severe in patients with bicuspid than in those with tricuspid aortic valve disease. In the pulmonary trunk specimens, those 3 histologic features were also significantly more severe in patients with bicuspid than those with tricuspid valves (P =.001, P =.01, and P =.04, respectively). Seventy-five percent of patients with bicuspid aortic valve disease had grade 3 degenerative changes, whereas only 14% of those patients with tricuspid aortic valve disease had similar degrees of degenerative changes.

CONCLUSION

Patients with bicuspid aortic valve disease have more severe degenerative changes in the media of the ascending aorta and main pulmonary artery than patients with tricuspid aortic valve disease. These findings may explain root and ascending aortic dilation in patients with bicuspid aortic valve disease and pulmonary autograft dilation in certain patients after the Ross procedure.

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.

Normalization of left ventricular dimensions after Ross operation with aortic annular reduction

BACKGROUND

Fifty-seven patients (August 1995 to November 1998) with a dysplastic dilated aortic root, a relative contraindication to the Ross operation, received an extended Ross operation with aortic annulus reduction and external cuff fixation (age 14-54 years). To assess the efficacy of these operations, echocardiographic assessment of autograft valve function and left ventricular function and dimensions were reviewed.

METHODS

Preoperative and postoperative assessment of 27 patients with aortic insufficiency (AI group) and 30 patients with aortic stenosis (>20 mm Hg peak gradient) and aortic insufficiency (AS group) were compared. Aortic annulus size, valvular gradient, valve insufficiency, left ventricular dimensions at end-systole and end-diastole, left ventricular fractional shortening, and left ventricular mass were assessed.

RESULTS

There was one late death. Aortic annulus size, degree of AI, left ventricular internal dimensions, and left ventricular mass were all significantly reduced (p<0.05) postoperatively in the AI group. Mean peak pressure gradients for this group were 6.8+/-6.7 mm Hg before operation and 8.7+/-6.4 mm Hg at 1 year after operation. Peak pressure gradient, aortic annulus size, degree of AI, left ventricular internal dimensions, and left ventricular mass were significantly reduced (p<0.05) in the AS group. Mean fractional shortening was within normal limits pre- and postoperatively for both groups.

CONCLUSIONS

Regression of left ventricular dilatation and hypertrophy, excellent autograft valve function, and survival suggest that this modification of the Ross operation may be offered to patients with a dysplastic aortic root requiring aortic valve replacement.

Exercise hemodynamic performance of the pulmonary autograft following the Ross procedure

BACKGROUND AND AIMS OF THE STUDY

The Ross procedure, in which the aortic valve is replaced with the patient's own pulmonary valve (pulmonary autograft), is considered an excellent alternative for younger patients requiring elective aortic valve replacement. Although resting pulmonary autograft hemodynamics are excellent, exercise hemodynamic data are lacking. The study aim was to measure the hemodynamic performance of the pulmonary autograft with exercise Doppler echocardiography (DE).

METHODS

Twenty-four Ross procedure patients (20 males, four females; mean age 46 +/- 11 years) were studied at 25 +/- 14 months after aortic valve replacement with a pulmonary autograft. Patients had baseline supine DE to measure the maximum velocity (Vmax), and the peak and mean pressure gradient across the pulmonary autograft. Effective orifice area was calculated from the continuity equation and indexed to body surface area (EOAi). Patients then underwent symptom-limited upright bicycle exercise with supine DE repeated immediately on stopping exercise. For comparison, 10 normal controls (age 41 +/-10 years) and five mechanical aortic valve patients (mean age 55 +/- 10 years) were studied.

RESULTS

At rest: Ross procedure patients had similar Vmax (1.2 +/- 0.2 m/s), peak gradient (6 +/- 2 mmHg), mean gradient (4 +/- 1 mmHg) and EOAi (1.7 +/- 0.4 cm2/m2) to those of normal controls. Mechanical-valve patients had significantly higher Vmax (2.5 +/- 0.2 m/s, p <0.001), peak gradient (25 +/- 4 mmHg, p <0.001) and mean gradient (14 +/- 3 mmHg, p <0.001) than Ross patients and normal controls. At exercise: Ross procedure patients had similar Vmax (1.8 +/- 0.4 m/s versus 2.1 +/- 0.2, p = NS), peak gradient (14 +/- 6 mmHg versus 17 +/- 4, p = NS) and mean gradient (8 +/- 4 mmHg versus 10 +/- 2, p = NS) to normal controls, with no significant change in EOAi. Mechanical-valve patients had significantly higher Vmax (3.4 +/- 0.3, p <0.001), peak gradient (48 +/- 7 mmHg, p <0.001) and mean gradient (30 +/- 5 mmHg, p <0.001) than Ross patients and normal controls.

CONCLUSIONS

Aortic valve replacement using the Ross procedure provides excellent hemodynamic results at rest and on exercise, with DE parameters indistinguishable from those of normal controls. This study provides further support for the use of the Ross procedure as a preferred method of aortic valve replacement in younger patients.

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.

Aortic valve replacement: is the stentless xenograft an alternative to the homograft? Midterm results

BACKGROUND

This study was performed to assess the midterm clinical results after aortic valve replacement (AVR) with stentless xenograft (SX) compared with cryopreserved aortic or pulmonary homografts (HX).

METHODS

In 139 patients (<60 years) undergoing elective AVR, 59 HX and 80 SX were inserted. All patients were followed clinically and by color flow Doppler echocardiography for 45+/-12 months (range 31-58 months).

RESULTS

There were 5 in-hospital deaths (3.5%): 4 HX and 1 SX (p = NS). The mean gradient was 6+/-2 mm Hg in HX versus 13+/-6 mm Hg in SX (p<0.001) and remained unchanged during follow-up. Actuarial survival (HX 77%, SX 80%), freedom from endocarditis (HX 91%, SX 99%), freedom from thromboembolic events (HX 98%, SX 90%), and freedom from reoperation (HX 98%, SX 100%) were comparable between groups after 58 months.

CONCLUSIONS

Despite slightly higher transvalvular gradients, the stentless aortic valve achieved excellent midterm results, when compared with homografts.

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.

Pulmonary autograft root replacement: mid-term results

BACKGROUND AND AIMS OF THE STUDY

The Ross operation was first performed as a root replacement in 1974, and only limited mid- and long-term results assessing durability and adaptation of the pulmonary root to systemic pressures are available. We reviewed our experience to assess function of the autograft valve and the autograft pulmonary root, and its adaptation to systemic pressures.

METHODS

A total of 244 operative survivors (median age 22 years; range: 1 week to 62 years) were reviewed. Clinical follow up (within one year) was available on 98% of cases, and echocardiographic assessment within one year on 93%. Autograft and homograft valve function, aortic annulus diameter, autograft root sinus diameter and ascending aortic diameter were determined on the most recent echocardiogram.

RESULTS

Actuarial freedom from autograft valve degeneration (non-endocarditis autograft valve reoperation or severe autograft valve insufficiency or valve-related death) was 95 +/- 3% at 5 years and 93 +/-4% at 10 years. Actuarial freedom from all valve-related complications (autograft valve degeneration, autograft valve reoperation, homograft valve reoperation or valve-related death) was 90 +/- 4% at 5 years and 83 +/-6% at 10 years. Actuarial freedom from autograft valve replacement was 98 +/- 2% at 5 years and 96 +/- 4% at 10 years. Actuarial survival rate was 98 +/- 2% at 5 years and 86 +/- 9% at 10 years. Aneurysmal dilation of the autograft root occurred in two patients; this was not associated with autograft valve degeneration, and these patients were followed closely.

CONCLUSIONS

At 10 years, the Ross root replacement has a low risk of valve degeneration, valve-related complications and autograft valve replacement, and patient survival is excellent. Autograft valve reoperation and homograft valve reoperation have been the only significant late valve-related complications. Techniques to reduce autograft reoperation have been introduced, and hopefully methods to mediate the immunological response to the homograft valve will reduce the incidence of failure. Significant aneurysmal dilation of the pulmonary autograft root is rare.

Valved homograft conduit repair of the right heart in early infancy

BACKGROUND

Valved homograft conduit repair in neonates and young infants creates a physiologically normal biventricular circulation, and unlike shunts, avoids surgery on the branch pulmonary.

METHODS

Retrospective chart review was used for 84 patients operated on between 1990 and 1995 (mean age 26+/-28 days, mean weight 3.3+/-0.8 kg) undergoing homograft conduit repair in the first 3 months of life. Cases were divided into simple and complex, eg, absent pulmonary valve syndrome or associated interrupted arch. Mean homograft size was 9.0+/-2 mm.

RESULTS

Early mortality was 4.7% (simple) and 30% (complex). Mean hospital stay was 18 days. Mean follow-up was 34 months. Thirty-seven (47%) patients underwent conduit replacement. Median time to reoperation was 3.1 years. Mean size of replacement homograft was 17+/-2 mm. There were no deaths at reoperation. Mean hospital stay at conduit change was 6.3 days. Probability of survival at 5 years is 75%.

CONCLUSIONS

Biventricular repair employing a conduit can be performed safely in noncomplex anomalies in the first 3 months of life. Time interval until repeat surgery is relatively short but equal or greater than that with most palliative procedures.

Mitral valve replacement with a pulmonary autograft: initial experience

BACKGROUND AND AIM OF THE STUDY

For long-term substitution of the mitral valve, mechanical prostheses require life-long anticoagulation which is impractical in developing countries, xenografts degenerate early in our young population, and mitral homografts have not yet been established as being suitable. We therefore returned to an original concept first reported by one of the authors (D.N.R.) in 1967.

METHODS

Between July 1997 and November 1998, 22 patients (mean age 40.3 years; range: 28 to 57 years) with rheumatic mitral valve disease unsuitable for reconstruction were subjected to excision of their pulmonary valve in the standard fashion of the Ross procedure. The inverted autograft was incorporated in a 2.5 cm-long Dacron conduit, with a pericardial collar attached to its proximal end. The distal end of the autograft-conduit was sutured to the annulus of the excised mitral valve, and the proximal end incorporating the pericardial collar was attached to the adjacent atrial wall. In this way all prosthetic material was covered. The right ventricular outflow was reconstructed with a pulmonary homograft in 17 patients, with an aortic homograft in two, and with a porcine pulmonary xenograft in three.

RESULTS

One patient developed a fatal cerebrovascular accident, probably related to an incorrectly placed pericardial collar with rough surface exposed to the blood flow. In a second patient the autograft had to be replaced six weeks after operation due to bacterial endocarditis contracted in the operating room. Echocardiography confirmed excellent function of the remaining autografts up to 16 months postoperatively (mean follow up 8.3 months).

CONCLUSIONS

We believe the pulmonary autograft to be a valid option for mitral valve replacement in our patients.