Autograft or Allograft Aortic Root Replacement in Children and Young Adults With Aortic Valve Disease: A Single-Center Comparison

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1 Autograft or Allograft Aortic Root Replacement in Children and Young Adults With Aortic Valve Disease: A Single-Center Comparison Mark Ruzmetov, MD, PhD, Dale M. Geiss, MD, Jitendra J. Shah, MD, and Randall S. Fortuna, MD Children s Hospital of Illinois, OSF Saint Francis Medical Center, and University of Illinois College of Medicine at Peoria, Peoria, Illinois Background. We analyzed the outcome of children and young adults (younger than 40 ) with aortic valve disease who underwent allograft or autograft aortic root replacement (ARR) in our institution and evaluated whether there is a preference for either valve substitute. Methods. One-hundred fifty patients younger than 40 underwent ARR between January 1990 and July Forty-four patients, aged , had ARR with allograft conduit (allograft group), whereas 106 patients, aged (p 0.63), had a ARR during the same period of time (autograft group). Echocardiographic data were reviewed to evaluate valve performance. The 2 groups were similar with respect to age, gender, etiology, and previous and concomitant procedures. Results. Operative deaths were 3 in the autograft group. There were 6 late deaths in the autograft group and 5 in the allograft group. Survival was 92% and 84% at 5 and 15, respectively, in the allograft group versus 93% and 91% in the autograft group (p 0.42). Freedom from any type of reintervention and from reoperation on aortic valve were similar (autograft, 64% and 72% versus allograft, 66% and 66%; p not significant) at 15. Freedom from explantation were significantly better for patients (autograft, 82% versus allograft, 66%; p 0.05). Conclusions. Aortic valve replacement with either the autograft or allograft provides good clinical results in children and young adults during an intermediate duration of observation. Survival early after ARR does not differ depending on the type of prosthesis. In patients with aortic valve disease, autograft and allograft ARR show comparable satisfactory early and long-term results, with the increasing reoperation risk in the second decade after operation remaining a major concern. (Ann Thorac Surg 2012;94: ) 2012 by The Society of Thoracic Surgeons The optimal prosthesis choice in young adults requiring aortic valve or root replacement (ARR) remains controversial. For patients who require ARR, the 2 valve substitutes available are mechanical prosthesis and tissue valves (bioprosthesis, allograft and autograft). All valve types have their specific advantages and disadvantages. In the search for a long-lasting, durable, and nonthrombogenic valve, which has the potential of restoring the normal hemodynamic profile in the aortic root, increased interest has been focused on the aortic allograft and the pulmonary autograft. Aortic allografts have been used for several decades with good long-term results, particularly when implanted as freestanding aortic roots [1]. In comparison with more obstructive prostheses, their lower transvalvular gradients are associated with better left ventricular mass regression [2]. They also show good resistance to infection and other valve-related complications [2 6]. Accepted for publication May 1, Presented at the Forty-eighth Annual Meeting of The Society of Thoracic Surgeons, Fort Lauderdale, FL, Jan 28 Feb 1, Address correspondence to Dr Fortuna, Children s Hospital of Illinois, OSF Saint Francis Medical Center, 515 NE Glen Oak Ave, Ste 202, Peoria, IL 63603; rfortuna@ilcardiac.com. However, in part because of low-grade immunologic mechanisms, allografts can undergo late degeneration marked by heavy calcification and valve dysfunction. This finding, coupled with limited availability of allografts has stimulated the search for other substitutes with a similar hemodynamic profile and equal or better durability. The procedure, first described by in 1967 [7], is an attractive option for the treatment of aortic valve disease in children and selected adults [8]. The limited application of this procedure has centered on the technical difficulty of the operation and concerns about early and late autograft and allograft failure. With added experience, the advantages of the procedure, including superior hemodynamic performance, low risk of endocarditis and thromboembolism, avoidance of longterm anticoagulation, and the potential for autograft growth in children, have become more fully appreciated [9 11]. The procedure was offered to all children, young adults, and older patients with isolated aortic valve disease, an active lifestyle, and the desire to avoid anticoagulation. However, autograft failure due to dilatation or insufficiency is an important complication that emerges in a 2012 by The Society of Thoracic Surgeons /$36.00 Published by Elsevier Inc

2 Ann Thorac Surg RUZMETOV ET AL 2012;94: AORTIC ROOT REPLACEMENT COMPARISON 1605 Table 1. Preoperative Patient Characteristics Variable (n 106) Allograft (n 44) p Value Age (, mean SD) Range 1 month 40 2 weeks 40 Infants ( 1 year age) 9 (9%) 6 (14%) 0.38 Children ( 1 year age) 59 (56%) 19 (43%) 0.21 Adults ( 18 age) 38 (36%) 19 (43%) 0.46 Male/Female 71 (67%):35 (33%) 29 (66%):15 (34%) 0.87 Size of neo-av (mm, mean SD) Range Etiology Stenosis 66 (62%) 20 (45%) 0.07 Insufficiency 40 (38%) 24 (55%) Pathology Congenital 87 (82%) 24 (55%) Chronic rheumatic 6 (6%) 4 (9%) 0.48 Endocarditis 10 (9%) 12 (27%) 0.01 Other (including Marfan) 3 (3%) 4 (9%) 0.19 Previous aortic valve procedures 45 (43%) 18 (41%) 0.85 Concomitant procedures 40 (38%) 21 (48%) 0.28 AV aortic valve. significant proportion of patients during long-term follow-up [10, 11]. In recent, several groups have the incidence of autograft dysfunction resulting from progressive dilatation of the neoaortic root and allograft (from right ventricular outflow tract position, RVOT) failure. We analyzed the outcome of children and young adults (younger than 40 ) with aortic valve disease who underwent allograft or autograft ARR in our institution and evaluated whether there is a preference for either valve substitute. Material and Methods One-hundred fifty patients younger than 40 underwent ARR between January 1990 and July 2011 at Children s Hospital of Illinois, OSF Saint Francis Medical Center, and University of Illinois College of Medicine at Peoria, Peoria, Illinois. Forty-four patients, aged , had ARR with allograft conduit (allograft group), whereas 106 patients, aged (p 0.63), had a procedure (autograft group) during the same period of time. The choice of valve for ARR was made preoperatively or in the operating room by the surgeon without randomization. Fifteen patients (10%) were neonates and 57 patients (38%) were greater than 18 old. We reviewed the medical records with regard to the initial clinical features, pathophysiological findings, surgical treatment, and hospital mortality. The preoperative characteristics of these 150 patients are displayed in Table 1. Approval from the Institutional Review Board of the University of Illinois College of Medicine at Peoria was obtained for this study. Demographic information, cardiac anatomy, preoperative hemodynamics, operative details, and postoperative outcomes were recorded retrospectively from patient records. Transthoracic echocardiography was used to evaluate valves gradients and the degree of valves insufficiency. Stenosis was assessed by the measurement of peak velocity through the valve using a continuous wave Doppler technique. Pulsed color-flow Doppler was used to detect neoaortic regurgitation by the evaluation of a regurgitated jet. The peak and mean systolic gradient were measured using the modified Bernoulli equation. Valve regurgitation was quantified as trivial, mild, moderate, and severe using grades 1, 2, 3, and 4, retrospectively [12]. All allografts (for neoaortic replacement in the allograft group and for RVOT reconstruction in the autograft group) were obtained from CryoLife, Inc (Marietta, GA). No patient received a prosthesis that was undersized from a larger allograft. Blood group matching could not be accommodated because allograft availability in sizes appropriate for this patient population was extremely low. Conduit size was determined according to the calculated z value for each implanted valve using the valve diameter compared with the normal value. Our goal was to insert a conduit with a z score of 1 to 3. Figure 1 shows the distribution and frequency of ARR. Allografts were frequently inserted within the period of our study; thereafter, the procedure was more commonly used to establish neoaortic continuity during the period from 1994 to The patient demographics are summarized in Table 1. The 2 groups were similar with respect to age, gender, etiology, diameter of neoaortic valve, and previous and concomitant procedures. Endocarditis was the most common indication for allograft insertion, with the procedure more frequently employed in the congenital morphology.

3 1606 RUZMETOV ET AL Ann Thorac Surg AORTIC ROOT REPLACEMENT COMPARISON 2012;94: Fig 1. Distribution of all aortic root replacement procedures between January1990 and July (pts patients.) number of pts Allograft Operative Technique Root replacement was performed as a freestanding root with reimplantation of the coronary arteries in all autograft patients (n 106) and all allograft patients (n 44). The autograft or allograft root was placed in the left ventricular outflow tract (LVOT) and annulus with a short rim of right ventricular muscle that was kept to a minimum, and no measures were taken to reinforce the aortic root or sinotubular junction. Either continuous or interrupted sutures were used for the proximal anastomosis, depending on surgeon preference. Initially in this series the autograft was placed on the annulus; in more recent particular attention has been paid to place the autograft inside the annulus. During the autograft procedure, reconstruction of the RVOT was done using an allograft. The RVOT was constructed with a pulmonary allograft (cryopreserved, n 83; decellularized, n 13; CryoLife) oversized 4 to 6 mm larger than the autograft. Surgical procedures were performed on cardiopulmonary bypass with moderate hypothermia. Crystalloid cardioplegia and topical cooling were used for myocardial protection. Patients receiving homografts were given ibuprofen postoperatively and transitioned to lifetime aspirin (10 mg/kg/day) at discharge. Follow-Up All surviving patients were examined by their referring cardiologist in the immediate postoperative period and reexamined with serial transthoracic echocardiography every 6 months or 1 year until August Follow-up was 94% for both cohorts. For the allograft group, the mean follow-up was , ranging from 3 months to 20. The mean follow-up for the autograft group was not significantly different at , ranging from 4 months to 17 (p 0.64). Early death was defined as death in the hospital or within 30 days of discharge. All other deaths were considered late. Statistical Analysis Data are presented as the mean SD. Continuous variables were analyzed with the Student t test and categoric variables using the 2 test. Variables for the 2 cohorts were compared using the 2-tailed unpaired t test. Kaplan-Meier curves for actuarial survival, freedom from any type of reintervention (on both valves), and reoperation on a neoaortic valve from neoaortic valve explantation were calculated using the statistical package SPSS for Windows (SPSS Inc, Chicago, IL). Endpoints were time of death, first diagnosis of valve (aortic or pulmonary) insufficiency, interventional or surgical reintervention, and valve replacement, respectively. The logrank test was used to estimate the statistical difference between the 2 types of procedures. The significance level was set at a p value of 0.05 or less. Results Survival and Morbidity There were 3 early deaths (2%; 3 of 150). All early deaths were in the autograft group (3%; 3 of 106) and all occurred in patients with a -Konno procedure. A 3-month-old patient died at 6 days after a -Konno procedure and mitral valvuloplasty for LVOT obstruction, and severe mitral insufficiency due to multisystem organ failure. This patient at age 10 days underwent complete atrioventricular canal repair, subaortic membrane resection, and coarctation of the aorta repair. One month later, the patient underwent mitral and tricuspid valve repair due to severe mitral and tricuspid insufficiency. The second death occurred in a 2-week-old with Shone anomaly who underwent a -Konno procedure with resection of the endocardial fibroelastosis as a result of an intracerebral hemorrhage while being weaned from extracorporeal membrane oxygenation. The third death occurred in a 19-month-old patient with Shone anomaly who previously had coarctation repair and subaortic membrane resection. This patient died 20 days after surgery on left ventricular assist device due to left ventricular failure. There were 6 late deaths in the autograft group and 5 in the allograft group. The causes of late deaths are shown in Table 2. Overall actuarial survival was 92% and 84% at 5 and 15, respectively, in the allograft group versus

4 Ann Thorac Surg RUZMETOV ET AL 2012;94: AORTIC ROOT REPLACEMENT COMPARISON 1607 Table 2. Causes of Late Death Cause Allograft Noncardiac 2 1 Low cardiac output 0 2 Pneumonia 1 1 Arrhythmia 1 0 Unknown 2 1 Total % and 91% in the autograft group (p 0.42) (Fig 2). Late deaths occurred in a median time of 3 (range, 2 months to 12 ); 5 were infants (46%) at the time of initial surgery. There was a significant difference in survival in the allograft group between infants and young adults (p 0.05). In the autograft group we did not find any significant differences according to age (infants, children and young adults). Three patients required extracorporeal membrane oxygenation for postoperative low cardiac output and 1 patient required left ventricular assist device for left ventricular failure (all patients from the autograft group). Two patients expired; 1 during weaning from extracorporeal membrane oxygenation and the second on a left ventricular assist device (stated above). The remaining 2 patients who were successfully weaned from extracorporeal membrane oxygenation are all long-term survivals. Additional morbidity included reexploration for bleeding in 1 patient (autograft group) and complete heart block requiring permanent pacemaker insertion in 5 patients (autograft, n 3 and allograft, n 2). Overall, freedom from postoperative morbidity was similar (autograft 92% versus allograft 96%; p not significant). Reinterventions Fifty-two patients (35%, 52 of 147) underwent reoperation at a median interval of 7.5 (mean, ; range, 1 month to 14 ). The mean interval time of reoperations was higher for autograft patients but was not significantly different (autograft versus allograft, ; p 0.07). Among these patients, 38 were from the autograft group (37%, 38 of 103) and 14 patients were from the allograft group (32%; 14 of 44). Thirty patients required neoaortic reinterventions (autograft, n 18 and allograft, n 12), 14 patients (autograft, n 12 and allograft, n 2) required simultaneous reinterventions on the neoaortic and the neopulmonary valves, and 8 patients (autograft group) required isolated allograft replacement. Among the 44 patients (30 isolated, 14 concomitant with pulmonary valve redo), progressive dilatation of the neoaortic root (n 6), moderate to severe neoaortic insufficiency (n 15), or both (n 19) were the cause for neoaortic reintervention. A valve-sparing root replacement with resection of the ascending aorta aneurysm was performed in 13 patients (all from the autograft group; 4 of these patients followed later aortic root replacement [Bentall operation]). Aortic valve replacement for severe neoaortic insufficiency was performed in 15 patients. The ARR with a composite mechanical or biologic valve and graft was performed in 16 patients. The mean interval between initial operation and neoaortic reintervention was (range 1 month to 14 ). During the reoperation on the neoaortic valve, 13 patients underwent a valve-sparing root replacement (modified David procedure) and aortic valve or root replacements were performed in 31 patients, and included the following: mechanical prosthesis (n 15), new allograft, including decellularized SynerGraft (CryoLife; n 10), bioprosthesis (n 5), procedure (n 1, from the homograft group). The choice between mechanical and biologic prostheses is based on numerous considerations, including patient age and surgeon-patient preference. Among the 22 patients (14 concomitant with autograft redo; 8 isolated) reoperated on for pulmonary allograft stenosis (n 18) or regurgitation (n 4), a second non-decellularized pulmonary allograft was inserted in 14 patients, a decellularized pulmonary allograft in 5, a porcine valve in 1, and a bovine pericardial valve in 2 patients. The mean interval between initial operation and autograft reoperation was (range, 3 months to 14 ). There are no significant differences p=0.42 Fig 2. Kaplan-Meier estimate of patient survival. Hospital deaths are included. survival Aortic Allograft Patients at Risk 1yr 5yrs 10yrs 15yrs Allograft % 84%

5 1608 RUZMETOV ET AL Ann Thorac Surg AORTIC ROOT REPLACEMENT COMPARISON 2012;94: Fig 3. Kaplan-Meier estimate freedom from any type of reintervention (neoaortic and neopulmonary). freedom from any type of reintervention Patients at Risk 1yr 5yrs 10yrs 15yrs Allograft Aortic Allograft p= % 64% between mean interval time between neopulmonary and neoaortic reoperation (p 0.54). Freedom from any type of reintervention (neoaortic and neopulmonary valves; autograft 64% versus allograft, 66%;, p 0.96; Fig 3) and from reoperation on a neoaortic valve (autograft 72% versus allograft, 66%; p 0.32; Fig 4) were similar at 15. Freedom from aortic explantation (autograft or allograft) were significantly better for patients (autograft, 82% versus allograft, 66%; p 0.05; Fig 5). There are no significant differences between the groups according to ages (infants versus children versus young adults). Freedom from reoperation was not significantly different between children and young adults in both groups (autograft and allograft). Follow-Up and Echocardiography Follow-up was 94% complete (138 of 147 patients). The mean follow-up time was (range, 3 months to 20 ). For the allograft group, the mean follow-up was , ranging from 3 months to 20. The mean follow-up for the autograft group was not significantly different at , ranging from 4 months to 17 (p 0.64). All surviving patients are doing well and have not required medication after the third postoperative month. Thirty-one patients (23%; 29 autograft patients and 2 allograft patients) have aortic root dilatation ( 40 mm); 25 of these patients (18%) have met the criteria for elective valve-sparing or prosthetic root replacement. Aortic root dilation has occurred during (range, 1 to 15 ). Freedom from autograft sinus or ascending aortic dilatation greater than 40 mm at 15 was 77%. Freedom from neoaortic root dilatation was significantly better for allograft patients compared with autograft patients at 15 (allograft 95% versus autograft 70%; p 0.001). Freedom from neoaortic dilatation was not significantly different between the groups according to age (infants versus children versus young adults). Freedom from neoaortic dilatation also was not significantly different between children and young adults in both groups (autograft and allograft). Comment Within this large group of patients, a smaller subgroup of grown-ups who are in their teens or early adulthood Fig 4. Kaplan-Meier estimate freedom from reoperation on neoaortic valve. 100 freedom from reoperation on neo-aortic valve Aortic Allograft Patients at Risk 1yr 5yrs 10yrs 15yrs Allograft p= % 66%

6 Ann Thorac Surg RUZMETOV ET AL 2012;94: AORTIC ROOT REPLACEMENT COMPARISON Fig 5. Kaplan-Meier estimate freedom from aortic valve explantation. freedom from aortic valve explantation Aortic Allograft Patients at Risk 1yr 5yrs 10yrs 15yrs Allograft % p= % (younger than 40 ) present unique and demanding aspects. In contrast to younger children, in whom growth needs to be accommodated, these patients have often reached full body size and are thus theoretically candidates to a definitive prosthetic device. In contrast to adult and elderly patients they face a full life span and need to lead an active lifestyle, including school or work attendance, normal social relations, with the possibility of marriage and pregnancy, and regular physical activity. More than any other patient group, these patients need unlimited durability and minimal morbidity of the graft used for ARR. The original stentless valve was the aortic allograft pioneered by and Barratt-Boyes, and developed extensively by Yacoub and others [13, 14]. Aortic allografts have been used for several decades with good long-term results, particularly when implanted as freestanding aortic roots [1]. They also show good resistance to infection and other valve-related complications [2, 4]. However, in part because of low-grade immunologic mechanisms, allografts can undergo late degeneration marked by heavy calcification and valve dysfunction. Morphologic changes seen in aortic allograft valves include the loss of normal surface endothelium, stainable deep connective tissue cells, and the presence of focal areas of cell-oriented calcification; changes that are known to be more pronounced the longer the valve is implanted [3, 5]. Cryopreserved aortic allografts elicit a substantial allogenic response in recipients, leading to the histopathologic changes noted [9, 15]. These findings, coupled with limited availability of allografts, have stimulated the search for other substitutes with a similar hemodynamic profile and equal or better durability. One of the great advantages of the allograft is the fact that this is a true biologic valve containing no artificial material and therefore lends itself to the problem of infective endocarditis, particularly when complicated by an aortic root abscess [16]. Allografts allow the complete avoidance of prosthetic material and are therefore more resistant to infection. The placement of an allograft root in an aortic root abscess allows exclusion of the infected material from the circulation and is associated with a much reduced incidence of recurrent endocarditis. In a series reported by Gulbins and colleagues [17], 77 patients received valve replacement (allografts and mechanical valves) for native valve endocarditis. The difference in mortality was greater in the presence of an aortic root abscess; 13% for allograft and 57% for mechanical valves (p 0.05). In the absence of an abscess, the authors achieved similar results for the 2 valves; 11% for allograft and 13% for mechanical valves (p not significant). In the search for a permanent biologic solution for the aortic valve disease,, in 1967 introduced the pulmonary autograft, providing a living autologous valve for the aortic position, while an allograft could be placed in the RVOT, a low-pressure, low-stress environment. In the pioneer series from and colleagues [8] the determined mortality was 25% at 15 and 39% at 20, and the freedom from autograft replacement was 75% at 20. With added experience, the advantages of the procedure, including superior hemodynamic performance, low risk of endocarditis and thromboembolism, avoidance of long-term anticoagulation, and the potential for autograft growth in children, have become more fully appreciated [9 11, 18, 19]. The current study demonstrates that ARR in children with either an allograft valve or the pulmonary autograft can be performed safely and with good early and midterm results in the vast majority of patients. Previous experience with ARR in teenagers and young adults has demonstrated satisfactory preliminary results using either allografts or pulmonary autografts [3, 20 22]. Although allograft ARR remains a valid surgical option and requires a shorter and less demanding operation, reports that document the limited long-term durability of these valves are now gathering [3, 23]. Accordingly, estimates of freedom from structural deterioration and reoperation of 86% and 82% at 8 cannot represent optimal outcomes in the young patient [23]. In spite of the more complex procedure, autograft ARR has gained widespread acceptance as the better operation in the adoles-

7 1610 RUZMETOV ET AL Ann Thorac Surg AORTIC ROOT REPLACEMENT COMPARISON 2012;94: cent and young adult because of the expectation of longer durability of the viable valve [21, 24]. In the pediatric population, there have been few data addressing the hypothesis that the autograft is superior to the allograft in terms of clinical or hemodynamic outcomes. One of the earliest studies [22] that does address this found no significant differences among children receiving autograft or allograft ARR with respect to valve-related deaths or reoperation. This pioneering work, reflecting an earlier era of technique and myocardial preservation methods, had a relatively higher operative mortality than would be expected today, and the ratio of autografts to allografts, approximately 1:3. There are some definite contraindications to the operation, in particular acute rheumatic fever, juvenile rheumatoid arthritis, systemic lupus erythematosus, ankylosing spondylitis, and Libman-Sacks endocarditis. Another situation in which the autograft procedure is less desirable is in the patient with Marfan syndrome. Although there is a paucity of data regarding the ultrastructure of the pulmonary valve and artery in this syndrome, it should be assumed that autografting of such a valve would likely lead to dilatation and a risk of dissection. The results of allograft ARR in Marfan patients are less than optimal as well, with 1 of the 2 Marfan patients in this series undergoing allograft ARR eventually requiring valve re-replacement. We currently prefer the David procedure as a better approach for children with Marfan syndrome. This study supports previous studies of autograft and allograft ARR in pediatric and adult populations that have found good clinical outcomes from either operative technique. One of the largest series addressing this issue demonstrated no significant differences in survival, freedom from reoperation, freedom from valve graft degeneration, and freedom from all valve-related complications at 10 after ARR [25]. These authors also noted, however, that there is a trend toward somewhat greater tissue degeneration in allografts beyond 8, and concluded that this suggested a stronger case for autograft use in younger patients. A large randomized trial of autografts and allografts in a mostly adult population also found no significant differences based on type of ARR employed [15]. The maximum follow-up in that series was only 21 months, however, and this may have limited the opportunity to observe important differences. Dilation and regurgitation are the primary causes of pulmonary autograft failure and the principal reason for a reoperation after a procedure. Root replacement technique, male sex, preoperative aortic insufficiency, and aortic annulus size above 27 mm are associated with a higher probability of reoperation on the pulmonary autograft and late postoperative aortic regurgitation [10, 11, 19, 20]. The valve annulus, sinuses of Valsalva, and sinotubular junction may increase in size after the root replacement in as many as 20% to 25% of patients [10, 11]. Early in our experience (before 2004), we did not routinely fix the aortic annulus or sinotubular junction with a Dacron strip unless the aortic annulus was dilated and needed reduction. We presently use aortic annulus and sinotubular junction fixation with synthetic material in all older adolescents and adults whose aortic annulus (z score) is greater than 1. We reduce the aortic annulus if it is dilated. Elkins and colleagues [20] describe that the only independent predictors of development of moderately severe or severe autograft regurgitation were increasing age at the time of the operation, autograft regurgitation at completion of the ARR, and increasing follow-up time. Although the exact causes of autograft root dilatation remain to be determined, several factors may play a role, one of which is the root replacement technique. Sievers and colleagues [26] reported their results of the subcoronary technique over a 14-year period in 501 patients. Freedom from autograft and homograft reoperation was 92% at 10. No reoperation owing to dilatation of the ascending aorta was observed. They concluded that although a certain risk for reoperation does exist with the subcoronary technique, for the observed time period of up to 14 postoperatively this risk remains low and no exponential increase of the reoperation rate with time is observed, in contrast to the full root technique. Pulmonary allograft regurgitation after a procedure requiring replacement has been rare in our experience (4 patients). Allograft stenosis in most large series is 5% to 10%, with infants having the highest rate of up to 25% at 4 [25, 27, 28]. Overall, 20 patients (19%) have required reoperation for allograft dysfunction in our series. The mean interval between initial procedure and allograft reoperation was (range, 10 months to 14 ). Freedom from allograft reoperation was 96% at 5 and 81% at 15. This low incidence of allograft obstruction is secondary to the ability to oversize the homograft by as much as 4 to 6 mm in diameter at the time of the ARR. Morales and colleagues [28] described their experience with RVOT reconstruction in patients (without oversizing the pulmonary allograft); freedom from RVOT replacement in their series was 76% at 5. Brown and colleagues [27] recommend to oversize the allograft by as much as 10 mm in diameter. In conclusion, ARR with either the autograft or allograft provides good clinical results in children and young adults during an intermediate duration of observation. Survival early after ARR does not differ depending on the type of prosthesis. In patients with aortic valve disease, autograft and allograft ARR show comparable satisfactory early and long-term results, with the increasing reoperation risk in the second decade after operation remaining a major concern. References 1. Palka P, Harrocks S, Lange A, Burstow DJ, O Brien MF. Primary aortic valve replacement with cryopreserved aortic allograft: an echocardiographic follow-up study of 570 patients. Circulation 2002;105: El-Hamamsy I, Clark L, Stevens LM, et al. Late outcomes following Freestyle versus Homograft aortic root replacement. J Am Coll Cardiol 2010;55: Luciani GB, Casali G, Santini F, Mazzucco A. Aortic root replacement in adolescents and young adults: composite

8 Ann Thorac Surg RUZMETOV ET AL 2012;94: AORTIC ROOT REPLACEMENT COMPARISON 1611 graft versus homograft or autograft. Ann Thorac Surg 1998;66(suppl 6):S Concha M, Aranda PJ, Casares J, et al. Prospective evaluation of aortic valve replacement in young adults and middleaged patients: mechanical prosthesis versus pulmonary autograft. J Heart Valve Dis 2005;14: Pepper JR. Homografts and autografts: which patients really benefit? J Heart Valve Dis 2004;13(suppl 1):S Kilian E, Oberhoffer M, Kaczmarek I, Bauerfiend D, Kreuzer E, Reichart B. Outcome after aortic valve replacement: comparison of homografts with mechanical prostheses. J Heart Valve Dis 2007;16: DN. Replacement of aortic and mitral valves with a pulmonary autograft. Lancet 1967;2: DN, Jackson M, Davies J. The pulmonary autograft a permanent aortic valve. Eur J Cardiothorac Surg 1992;6: Jones TK, Lupinetti FM. Comparison of procedures and aortic valve allografts in children. Ann Thorac Surg 1998; 66(suppl 6):S Brown JW, Ruzmetov M, Rodefeld MD, Mahomed Y, Turrentine MW. Incidence of and risk factors for pulmonary autograft dilation after aortic valve replacement. Ann Thorac Surg 2007;83: David TE, Omran A, Ivanov J, et al. Dilation of the pulmonary autograft after the procedure. J Thorac Cardiovasc Surg 2000;119: Robert O. Bonow, Blase A, et al. ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing committee to revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease). Circulation 2006;114:e Barratt-Boyes BG, Lowe JB, Cole DS, Kelly D. Homograft replacement for aortic valve disease. Thorax 1965;20: Yacoub MH, Rasmi NRH, Sundt T, et al. Fourteen-year experience with homovital homografts for aortic valve replacement. J Thorac Cardiovasc Surg 1995;110: Santini F, Dyke C, Edwards S, et al. Pulmonary autograft versus homograft replacement of the aortic valve: a prospective randomized trial. J Thorac Cardiovasc Surg 1997;113: Petrou M, Wong K, Albertucci M, Brecker SJ, Yacoub MH. Evaluation of unstented aortic homografts for the treatment of prosthetic aortic valve endocarditis. Circulation 1994;90: Gulbins H, Eckehard K, Roth S, Uhlig A, Eckart K, Reichart B. Is there an advantage in using homografts in patients with acute infective endocarditis of the aortic valve? J Heart Valve Dis 2002;11: Lupinetti FM, Duncan BW, Lewin M, Dyamenahalli U, Rosenthal GL. Comparison of autograft and allograft aortic valve replacement in children. J Thorac Cardiovasc Surg 2003;126: Klieverik LMA, Bekkers JA, Roos JW, et al. Autograft or allograft aortic valve replacement in young adult patients with congenital aortic valve disease. Eur Heart J 2008;29: Elkins RC, Knott-Craig CJ, Razook JD, Ward KE, Overholt ED, Lane MM. Pulmonary autograft replacement of the aortic valve in the potential parent. J Card Surg 1994;9(suppl 2): El-Hamamsy I, Eryigit Z, Stevens LM, et al. Long-term outcomes after autograft versus homograft aortic root replacement in adults with aortic valve disease: a randomized controlled trial. Lancet 2010;376: Gerosa G, McKay R, Davies J, DN. Comparison of the aortic homograft and the pulmonary autograft for aortic valve or root replacement in children. J Thorac Cardiovasc Surg 1991;102: O Brien MF, Finney RS, Stafford EG, et al. Root replacement for all aortic allograft valves: preferred technique or too radical? Ann Thorac Surg 1995;60(suppl 2):S Kouchoukos NT, Dávila-Román VG, Spray TL, Murphy SF, Perrillo JB. Replacement of the aortic root with a pulmonary autograft in children and young adults with aortic-valve disease. N Engl J Med 1994;330: Knott-Craig CJ, Elkins RC, Santangelo KL, McCue C, Lane MM. Aortic valve replacement: comparison of late survival between autografts and homografts. Ann Thorac Surg 2000; 69: Sievers HH, Stierle U, Charitos EI, et al. Fourteen experience with 501 subcoronary procedures: Surgical details and results. J Thorac Cardiovasc Surg 2010;140: Brown JW, Ruzmetov M, Shahriari A, Rodefeld MD, Mahomed Y, Turrentine MW. Midterm results of aortic valve replacement: a single-institution experience. Ann Thorac Surg 2009;88: Morales DLS, Carberry KE, Balentine C, Heinle JS, McKenzie ED, Fraser CD Jr. Selective application of the pediatric procedure minimized autograft failure. Congenital Heart Dis 2008;3: DISCUSSION DR DAVID BICHELL (Nashville, TN): I have a question while others may be thinking of some. The operation has undergone an evolution over the time period of this study, and I guess part of what led to that is an understanding that patients with primary aortic insufficiency have a greater rate of annular and neoaortic root dilation and modifications to reinforce the annulus and to more recently wrap the autograft have maybe started to attenuate some of that effect. Were any of those changes embarked upon over the period of this study? In other words, are the later es different from the earlier ones, and although the numbers are small, is there any suggestion of a separation of the data according to those changes? DR RUZMETOV: We did not do any modifications before, I think, 2002, in patients. And I have not compared results between these 2 time periods (before 2002 and after 2002). DR PETER J. GRUBER (Salt Lake City, UT): One question about the age groups. The 2 age groups means were the same and up to 40 of age. Do you have any data in your study regarding the durability of the aortic homograft in different age groups? DR RUZMETOV: No, we did not do any data analysis regarding the durability of the aortic homograft in different age groups.