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Click here to read this article as a CME activity
a Department of Cardiovascular Surgery, Centre Hospitalier Regional et Universitaire de Lille, Lille, France
c Department of Cardiology, Centre Hospitalier Regional et Universitaire de Lille, Lille, France
b Department of Biostatistics, Université Lille Nord de France, Lille, France
d Department of Cardiology, Groupement Hospitalier de l'Institut Catholique Lillois/Faculté libre de médecine, Lille, France
Accepted for publication June 27, 2011.
* Address correspondence to Dr Prat, Service de Chirurgie Cardio-vasculaire, Centre Hospitalier Regional et Universitaire de Lille, Hôpital Cardiologique, Boulevard du Pr Leclercq, 59037 Lille Cedex, France (Email: alain.prat{at}chru-lille.fr).
Presented at the Forty-seventh Annual Meeting of The Society of Thoracic Surgeons, San-Diego, CA, Jan 31–Feb 2, 2011.
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Abstract |
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 Top Abstract IntroductionPatients and MethodsResultsCommentDiscussionAcknowledgmentsReferences |
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Methods: Between March 1992 and February 2010, 336 consecutive patients had a Ross procedure (mean follow-up, 6.2 ± 4.9 years). Autograft implant technique was freestanding root replacement in 269 patients, subcoronary implantation in 52 patients and a modified root replacement with the autograft included in a Valsalva tube graft in 15.
Results: Subsequently, 38 patients (11.3%) underwent reoperations, for autograft dilatation in 23 and a significant autograft insufficiency in 9, at 9.6 ± 3.7 years and 2.6 ± 3.9 years, respectively. Aortic and pulmonary infective endocarditis occurred in 3 patients. Three patients underwent a non valve-related cardiac reoperation. Three patients received a transcatheter pulmonary valve implantation after 12.2 ± 1.7 years. At 15 years, freedoms for autograft and homograft explantation (with 95% confidence interval) were 83.3% (77.4%- to 9.2%) and 92.8% (87.6% to 97.9%), respectively. Native aortic valve regurgitation, indexed aortic annulus diameter exceeding 1.35 cm/m2 and autograft diameter were risk factors for dilated autograft reoperation (hazard ratio, 3.23 [95% confidence interval, 1.19 to 8.81], p = 0.02; 3.83 [0.9 to 16.33], p = 0.07 and 1.2 per mm [1.01 to 1.41], p = 0.03), respectively.
Conclusions: Autograft dilatation was the leading cause of reoperation in patients who underwent root replacement. Long-term follow-up is mandatory to determine whether modifications of the operative technique could limit autograft dilatation.
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Introduction |
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| PEDIATRIC CARDIAC SURGERY:
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Replacement of the aortic valve or aortic root with a pulmonary autograft (Ross procedure) provides a viable valve with potential advantages, including excellent hemodynamic function, ability to grow, and durability, with no need for anticoagulation. The procedure is widely used for aortic valve disease in growing patients and in young adults with an active lifestyle or a desire to become pregnant. Excellent short-term and midterm results have been demonstrated, with low operative mortality and low rates of valve-related deaths or complications [1–10].
In recent years, however, concern has been raised about the durability of this procedure [11–18]. A major drawback of the Ross operation is the progressive dilatation of the neosinuses of Valsalva, which occurs in 10% to 30% of late survivors [12], especially when a freestanding autograft root replacement is used. The need for autograft reoperation remains the principal limitation of the procedure. In most cases, a cryopreserved pulmonary homograft is used for reconstruction of the right ventricular outflow tract (RVOT) and is also subject to structural failure, with stenosis as the predominant indication for reoperation of the pulmonary conduit. The goal of this study was to analyze the reoperation causes, time of occurrence, management, and postoperative course after Ross procedure.
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Patients and Methods |
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TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionAcknowledgmentsReferences |
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Study Population
Between March 1992 and February 2010, 336 consecutive adult and pediatrics patients underwent a Ross operation in our institution and were monitored prospectively. Autografts were implanted according to the freestanding root replacement technique in 269 patients (80%), and the modified subcoronary implantation technique (with preservation of the noncoronary sinus) was performed in 52 (15.4%). In 2003 we introduced a modified root replacement technique with the autograft included in a Vascutek Gelweave (Terumo Cardiovascular Systems Inc, Ann Arbor, MI) Valsalva graft, which was used in 15 patients (4.4%) [19]. All operations were performed by the same surgeon (A.P.).
Right ventricular outflow tract reconstruction was performed with a cryopreserved pulmonary homograft (European Homograft Bank, Brussels, Belgium) in 275 patients (81.8%) and with a stentless porcine root in 61 (18.2%). The perioperative data are listed in Table 1.
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Reoperation Procedure
Reoperations were performed through a median sternotomy under normothermic cardiopulmonary bypass with intermittent anterograde cold blood cardioplegia. None of these reoperations had to be performed with a peripheral cardiopulmonary bypass.
When reoperation was due to a neoaortic root dilatation, the autograft root was opened longitudinally and the valve leaflets were inspected. After excision and mobilization of the coronary buttons, the excess autograft sinus wall was trimmed. In case of significant leaflet free-edge elongation, associated leaflet prolapse, or evidence of leaflet failure, a Bentall procedure was performed. When autograft cusps appeared anatomically normal, a valve-sparing root reimplantation technique was performed.
When reoperation was due to autograft valve regurgitation without root dilatation, the autograft was transversally opened, and a standard aortic mechanical valve implantation was realized. In cases of RVOT degeneration, redo RVOT reconstruction was performed with a cryopreserved pulmonary homograft or with a stentless porcine root.
Follow-Up
Patient-related data were prospectively obtained by means of physical examination in conjunction with echocardiographic evaluation at discharge, 6 months, and annually thereafter on an outpatient basis. Transthoracic M-mode, 2-dimensional color mode, and Doppler echocardiograms were obtained for all patients before hospital discharge and for most patients annually. The degree of autograft and neopulmonary regurgitation was semiquantitatively assessed and classified according to a 4-grade scale. Mean and peak gradients across both semilunar valves were measured with the use of continuous-wave Doppler. Because of the widespread origin of the patients, complete clinical and echocardiographic examinations from the referring cardiologists were also accepted. Mortality and reintervention were defined according to the latest guidelines (2008) for reporting mortality and morbidity after cardiac valve interventions [20].
The database was frozen on June 1, 2010. Follow-up was 92.1% complete at this time. The total follow-up was 2049 patient-years. The mean follow-up duration was 6.2 ± 4.9 years (maximum, 17.8 years).
Statistical Analysis
Statistical analyses were performed using SAS 8 software (SAS Institute Inc, Cary, NC). Continuous variables are reported as mean ± standard deviation, and categoric variables are reported as frequencies or proportions. Cumulative survival and freedom from reoperation, autograft, or homograft explantation were analyzed using the Kaplan-Meier method. Survival was displayed as the proportion and 95% confidence interval (CI).
The Cox proportional hazards regression analysis was used to evaluate the following variables as predictors for dilated autograft reoperation: age, sex, previous cardiac operation, preoperative aortic valve variables (regurgitation vs stenosis, bicuspid valve disease, aortic annulus diameter), ascending aorta aneurysm, homograft variables (diameter, donor/recipient blood mismatch), and surgical technique (root replacement, subcoronary technique, Valsalva prosthesis inclusion technique). The proportional hazard assumption was met for all variables. The log linearity assumption was met for all variables but for the aortic annulus diameter; the variable was then recoded into a binary variable, the cutoff value being the value minimizing the Schwarz's Bayesian criterion of univariate Cox models. Multivariate Cox proportional hazard models were built using the significant (p 
0.10) univariate predictors.
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Results |
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Univariate predictors for dilated autograft reoperation were preoperative aortic regurgitation (hazard ratio [HR], 3.23; 95% CI, 1.19 to 8.81; p = 0.02), indexed aortic annulus diameter exceeding 1.35 cm/m2 (HR, 3.83; 95% CI, 0.9 to 16.33; p = 0.07), and autograft diameter (HR, 1.2 per mm; 95% CI, 1.01 to 1.41; p = 0.03). In the multivariate analysis, no combination of univariate predictors reached significance, due to the low number of events or given the strong correlation existing between these predictors, or both. The univariate model is summarized in Table 5. No reoperations for autograft dilatation were performed in patients operated on with the modified subcoronary technique or the Valsalva prosthesis inclusion technique.
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Freedom from autograft explantation was 94.7% (95% CI, 92.1% to 97.3%) at 5 years, 88.8% (95% CI, 84.6% to 93%) at 10 years, and 83.3% (95% CI, 77.4% to 89.2%) at 15 years (Fig 3).
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Freedom from homograft explantation was 99.3% (95% CI, 98.3% to 100%) at 5 years, 98.1% (95% CI, 96.3% to 100%) at 10 years, and 92.8% (95% CI, 87.6% to 97.9%) at 15 years (Fig 4).
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All patients survived reoperation and were alive at the last follow-up. The mean intensive care unit stay after reoperation was 2 ± 1.9 days (range, 1 to 10 days). Postoperative significant morbidity included, in 1 patient each, rethoracotomy for persistent blood loss, stroke, pneumonia, and renal failure. The mean follow-up duration after reoperation was 2 ± 2.8 years. No major cardiac events were reported during this follow-up, including thromboembolic events, major bleeding events, endocarditis, or new reoperations.
Echocardiographic Results
Hemodynamic results at early postoperative control and at the last control are listed in Table 6. Patients undergoing reoperation, with their hemodynamic characteristics at the time of the reoperation, are included.
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Comment |
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Early mortality in our series was 3.3%, and actuarial survival at 15 years was 93.3% (95% CI, 90.4% to 96.2%). Early deaths were mainly represented by infants with complex multilevel left ventricular outflow tract disease and previous cardiac operations and by patients with poor left ventricular ejection fraction or acute endocarditis. Early mortality in adults was 1.7% (5 patients). Late deaths in 8 of 9 patients were due to noncardiac causes. These results are comparable to the estimates reported in other large series [2, 6, 7] and in a recent meta-analysis published by Takkenberg and colleagues [12], in which pooled early mortality for consecutive series was 3.04% (95% CI, 1.8 to 4.9) and pooled late mortality was 0.48%/patient-year (95% CI, 0.27% to 0.91%). Another recent report from the German-Dutch registry [17] stated that in the adult population, after exclusion of all early deaths, there were no significant differences in survival between the adult Ross patients and the normal population, underlining the overall good prognosis of the adult patients with Ross operations. Possible causes for this may be better patient selection, physiologic autograft hemodynamic characteristics, and a low incidence of endocarditis and autograft failure.
In ours series of 336 Ross procedures, 41 patients underwent reoperation or percutaneous implantation of valve prosthesis. Freedom from all-cause reoperation or reintervention was 87% at 10 years and 77.2% at 15 years. These results are in accordance with the data published by other authors [1, 6, 14, 25], emphasizing that the need for reoperation remains a major concern in these young patients. In their meta-analysis, Takkenberg and colleagues reported a pooled autograft deterioration linearized rate of 1.15% per year and a pooled RVOT conduit deterioration linearized rate of 0.91% per year [12].
Autograft dilatation was the leading cause of reoperation in our series (23 patients). Univariate predictors for reoperation due to autograft dilatation were preoperative aortic regurgitation, dilated aortic annulus, and dilated autograft. Aortic regurgitation had previously been reported as a risk factor for autograft dilatation in many series [6, 8, 14, 25], and recent reports by David and colleagues [14] and Ryan and colleagues [8] also identified aortic annulus dilatation as an independent predictor of pulmonary autograft failure.
Annular, root, and ascending aortic dilatation are frequently associated in patients with incompetent bicuspid aortic valves, David [26] suggested recently that this could be "a marker for premature degenerative changes in the aortic and pulmonary roots," which could explain the autograft's inability to sustain the high pressure in the systemic circulation [27]. All reoperations for autograft dilatation in our series were performed in patients who initially had a freestanding autograft root replacement. This technique is also a classically described risk factor for autograft dilatation [28, 29].
Several groups have proposed technical modifications to avoid autograft dilatation [30, 31]. External stabilization of the autograft annulus and sinotubular junction with polytetrafluoroéthylène (PTFE) felt or pericardium has been proposed because dilatation at these levels was proved to be rapidly associated with autograft insufficiency. Early and midterm results were promising; however, this procedure does not prevent dilatation of the neosinuses of Valsalva. In our series, aneurysmal evolution of their neoaortic root developed in 7 patients despite reinforcement of the proximal autograft suture line. Conversely, Sievers and colleagues [32] chose to return to the original Ross procedure (subcoronary or cylinder inclusion technique), with excellent results. However the cylinder inclusion technique is difficult to perform in cases of significant aortic-pulmonary root mismatch.
Similarly, a major dissymmetry is present between the 2 leaflets in some patients with bicuspid aortic valves, and subcoronary grafting is not feasible. The subcoronary technique is also contraindicated in the case of a large aortic aneurysm extending to the sinuses of Valsalva. Some have suggested that the subcoronary technique could lead to misalignment of the valve commissures and leaflets and induce greater stress on the valve components [33]. This hypothesis seems to be confirmed in our series: early autograft failure occurred in 5 patients after the subcoronary technique.
We recently described a technical modification of the Ross procedure with the pulmonary autograft implanted in a Vascutek Gelweave (Terumo Cardiovascular Systems Inc, Ann Arbor, MI) Valsalva graft [19]. Midterm results are promising, and our current policy is to propose this modified procedure when the aortic annulus exceeds 20 mm. In pediatric patients, where the growth potential of the pulmonary autograft would be prohibited if the autograft were included in prosthetic material, we would preclude this technical modification until a resorbable mesh would become available.
Our group is among several groups that have explored the feasibility of a conservative approach in selected patients [34, 35]. We performed aortic valve-sparing operations in 3 patients using a root reimplantation technique. The satisfying postoperative results remained stable over time, with a mean follow-up of 4.8 ± 2 years (range, 2.7 to 6.8 years).
A common criticism of the Ross procedure is that it can transform aortic valve disease into a potential double-valve disease. RVOT conduit deterioration rates, with the need for reoperation, have been reported at 0.12% to 1.27% per patient-year in adult series and between 0.4% and 4.9% per patient-year in pediatric series [12]. In our series, freedom from pulmonary homograft explantation was 98.1% at 10 years and 92.8% at 15 years. Only 3 patients met criteria for isolated RVOT replacement and could be successfully treated with catheter-based pulmonary valve implantation. This may be due to our policy of systematic oversizing of the allograft and the liberal use of antiinflammatory drugs in the postoperative period.
No operative deaths occurred and morbidity was low after reoperation in the present series. The 38 patients who required reoperation were young (median age, 35 years) and had few comorbidities. Redo operations can be performed relatively safely in such conditions. Some surgical steps are nevertheless technically challenging, such as excision of coronary buttons and mobilization or adherence dissection between the outflow tracts. Stulak and colleagues [11], from Mayo Clinic, recently reported their experience with 56 patients who underwent reoperation after the Ross procedure. They had to perform much more complex procedures than in our series and emphasized that, despite low operative mortality (1.8%), associated morbidity was considerable (11).
In conclusion, the Ross procedure is, in our institution, a safe and satisfying option to treat aortic valve disease in children and young adults. Careful systematic echocardiographic follow-up is mandatory to detect asymptomatic autograft and homograft failures, for which elective reoperations can be performed safely. Additional long-term follow-up data are needed to determine whether this new strategy is efficient to decrease autograft dilatation.
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Discussion |
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TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionAcknowledgmentsReferences |
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After the introduction in 1967 of the Ross procedure, it saw limited utilization until a reemergence and broad interest occurred in the late 1980s and early 1990s. Enthusiasm in the potential of a lifelong aortic valve associated with normal hemodynamic profile was tempered by the concern of creating 2 valves at risk and single-valve pathology. Early in the experience, many were most concerned about the fate of the right ventricular outflow tract (RVOT) and need for reoperation. However, the converse might be proving true, in that the autograft may pose a greater outcome risk than the right ventricle-to-pulmonary artery homograft, impacting enthusiasm in some for the procedure and limiting its utilization to a contracting group of centers. That said, your study is particularly timely and a significant contribution to the important challenge of us understanding how to enhance durability of the autograft and impart an enduring hemodynamic advantage to a rather heterogeneous patient population in which this technique is used.
Unfortunately, in the adult population compared with the pediatric subgroup, which seems to demonstrate different biologic properties of the pulmonary artery wall, the autograft is associated with up to a 20% reoperation rate and a 40% incidence of insufficiency at 20 years. Your series of 336 patients is consistent with that observation, demonstrating a freedom from autograft explantation of 83% and all cause reoperation or reintervention of 77% at 15 years. What is encouraging, however, in your study is the relatively low incidence of RVOT intervention, with a 15-year freedom of homograft explantation of 92%.
Focusing on the autograft, at our institution we have done several modifications to try to prevent aortic root dilatation, and in your series, most of those patients had the standard root replacement. What we have found is that use of felt buttressing tends to allow expansion of the annulus and fails to promote support. So we have converted to a Dacron patch material, and we also fix the distal suture line. In addition, we use β-blocker therapy to cut down on the wall stress by modifying dP/dt and hypertension. Did you in your series do any such modifications or use any such medical management strategy?
DR JUTHIER: Thank you for your question. When the primary cause of operation is aortic regurgitation or when the annulus is dilated, we use reinforcement with pericardium or Dacron felt, but in our experience, it failed to prevent reoperation in this group. Most of our patients were treated with β-blockers.
DR TURRENTINE: In your institution you are now performing the Valsalva graft autograft inclusion technique for all adult patients in which the aortic annulus exceeds a 20 mm diameter, and you have included 15 such patients in your series. The technique seems to address all anatomic components linked to autograft dilatation, that being the annulus, pulmonary artery wall and sinus, as well as the distal anastomosis and its impact on the sinotubular ridge. However, little was reported in your manuscript on the longitudinal outcomes of this group of patients. Could you tell us something about the autograft function over the 4 years you have used the technique and is there any anticipated long-term impact on the fate of the autograft in that inclusion graft? And specifically, do these short-term observations allow you to feel that you would suggest that this technique be used in all patients at 20 mm above, as perhaps selecting out a group that presents with an annular dilation of 26 mm or greater?
DR JUTHIER: Can you rephrase it, please?
DR TURRENTINE: You suggest using the inclusion graft technique for all patients with a 20-mm or above annular dimension. You had 4-year follow-up in 15 patients, so this was a relatively short period of time to draw significant conclusions, and not much was stated in your manuscript regarding the function of the valve in the inclusion graft or what you anticipate potentially technically with the long-term fate of the autograft inside the Valsalva graft. Does a short time frame allow you to draw good conclusions to suggest that this should be a standard approach?
DR JUTHIER: Thank you. Yes, our current practice is to apply our modification for each patient who has an aortic annulus diameter greater than 20 mm. You are right, our follow-up remains too short to draw any conclusion, but we didn't observe any aortic root dilatation over time; furthermore, we didn't observe any autograft regurgitation. Due to the design of the Valsalva prosthesis, normal autograft leaflet motion was maintained. However, longer follow-up remains mandatory.
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