Do surgical modifications at the annular level during the Ross procedure negatively influence the structural and functional durability of the autograft?

Do surgical modifications at the annular level during the Ross procedure negatively influence the... Abstract OBJECTIVES Do surgical modifications at the annular level (e.g. the modified Ross–Konno procedure or reduction plasty) influence the structure and function of the Ross autograft at the mid-term follow-up? METHODS From June 2001 to July 2009, 49 patients (37 men and 12 women), mean age 10.5 ± 5.7 years (range 2 weeks to 17.8 years), underwent Ross operations. Twenty-one patients underwent additional aortic annulus reduction plasty and 9 patients a modified Ross–Konno procedure. The need for reintervention, reoperation and valve function were retrospectively analysed for a mean follow-up of 4.6 ± 2.7 years (range 9 days to 9.2 years). RESULTS There were no intraoperative or early death. Three late deaths occurred. Survival at 4 years was 91.9 ± 4.6%. In the overall cohort, aortic annular growth was 1 mm/year, corresponding to a z-score increase of 0.24/year (no mismatch group), 0.21/year (reduction plasty group) and 0.34/year (Ross–Konno group). At the last follow-up, sinotubular junction z-scores were 2.8 ± 1, 3 ± 1 and 2.4 ± 0.9 in the no mismatch, reduction plasty, and Ross–Konno groups, respectively. Ninety-three percent of patients presented with none-to-mild autograft valve regurgitation. The Ross–Konno group showed a significant increase in aortic annulus size (z-score of the annulus at the last follow-up 3.6 ± 1.6; P = 0.036). The no mismatch and the reduction plasty groups showed z-scores within the normal range (2.1 ± 1.7 and 2.5 ± 1.6, respectively). CONCLUSIONS Additional aortic annulus reduction or enlargement does not disturb the structural and functional durability of the autograft at the mid-term follow-up. Long-term autograft integrity, especially in the Ross–Konno group, remains to be investigated. Ross procedure , Children , Modified Ross–Konno procedure , Aortic annulus , Left ventricular outflow tract , Echocardiography INTRODUCTION Aortic valve replacement (AVR) in adults using the pulmonary autograft was first described by Ross in 1967 [1]. Since then, the procedure has advanced and is now considered to be the AVR of choice in the paediatric population, including neonates and infants, due to the advantages of the avoidance of long-term anticoagulation, haemodynamic stability and the somatic growth potential of the autograft [2–4]. The results by Luciani’s et al. [5] on the use of the Ross operation in neonates, infants and children from the Italian Paediatric Ross Registry have recently been published. This study not only assesses survival and reoperation rates but also gives us additional meaningful data regarding the long-term structural and functional durability of the pulmonary autograft for 2 decades. A recently published retrospective study, involving 1501 children and young adults, comparing the Ross procedure and alternative AVR procedures (mechanical AVR, homograft AVR and bioprothesis AVR) shows that Ross patients had the highest event-free probability (death or any interventions at 10 years) [6]. Up until now, to our knowledge, only few published data are available with specific emphasis on surgical factors that might change the geometry of the junction portion between the left ventricular outflow tract (LVOT) and the neoaorta. In this article, we describe our experience with 49 children successively undergoing the Ross or the Ross–Konno procedure. Some of these patients underwent an additional surgery such as the modified Konno incision to enlarge the LVOT or reduction plasty at the annular or supra-annular level to correct autograft mismatch. The aim of this study was to determine whether these surgical manipulations which exceed the procedural requirements for the root replacement technique may lead to malfunction of the autograft or impede the somatic growth potential at the annular level when compared with the size-matched autograft at the mid-term follow-up. Therefore, we assessed the clinical and diagnostic results at the mid-term follow-up to evaluate autograft somatic growth, as well as haemodynamics, the need for reintervention or resurgery, heart rhythm and incidence of conduction disturbance after the procedure. PATIENTS AND METHODS Patient population All patients younger than 18 years who underwent a Ross or a Ross–Konno procedure between June 2001 and July 2009 at the University Hospital Zurich were enrolled in this study. Data were obtained from the cardiac surgery database, from medical records and from referring cardiologists with regard to the initial clinical features, surgical intervention and postoperative outcomes. There were 49 Ross procedures identified. For the purpose of this study, we divided the population into 3 groups. The no mismatch group (n = 19) underwent a Ross procedure as a full root technique, the reduction plasty group (n = 21) received a Ross procedure with a concomitant annulus reduction plasty and the 3rd group (n = 9) had a modified Ross–Konno procedure, including enlargement of the aortic annulus. The preoperative surgical indication for the procedure was aortic regurgitation for 29 (59%) patients and stenosis for 20 (59%) patients. Patients with both aortic stenosis and regurgitation were classified according to the predominant lesion. The underlying pathology was congenital aortic valve disease in all except 1 patient with aortic regurgitation caused by endocarditis. Bicuspid valve morphology was found in 63% of all cases. The mean age at operation was 10.5 ± 5.6 years (range 2 weeks to 17.8 years) including 2 neonates (Ross–Konno group) and 4 infants (3 Ross–Konno group and 1 reduction plasty group). Among the 49 operations, 2 were seen as emergency interventions due to congenital combined aortic valve disease with progressive cardiac failure (1 primary Ross surgery at the age of 5 weeks and 1 secondary Ross–Konno procedure at the age of 4 weeks s/p balloon dilatation). Patient demographics are given in Table 1. Table 1: Patient demographics, intraoperative and postoperative data Total (n = 49) No mismatch (n = 19) Reduction plasty (n = 21) Ross–Konno (n = 9) Gender  Male 37 (76) 17 (89) 15 (71) 5 (56%)  Female 12 (24) 2 (11) 6 (29) 4 (44%) Age (years) 12 (14.4–5.6) 13.2 (17.7–8.1) 14 (15.5–9.4) 0.9 (5.9–0.2) BSA 1.2 (1.6–0.8) 1.4 (1.7–1) 1.3 (1.6–1) 0.4 (0.8–0.2) Diagnosis  Aortic stenosis 20 (40) 9 (47) 4 (19) 5 (56)  Aortic regurgitation 29 (59) 10 (53) 17 (81) 4 (44) ECC (min) 223 (261–189) 223 (262–190) 223 (269–181) 225 (286–190) Cross-clamp time (min) 125 (143–116) 125 (139–115) 120 (146–118) 128 (160–112) Length of intensive care unit stay (days) 2 (4–3) 2 (2.25–1) 2 (3.75–1.25) 6 (7–3) Length of hospital stay (days) 11 (14–9) 10 (13–9) 11 (11–9) 17 (32–10) Total (n = 49) No mismatch (n = 19) Reduction plasty (n = 21) Ross–Konno (n = 9) Gender  Male 37 (76) 17 (89) 15 (71) 5 (56%)  Female 12 (24) 2 (11) 6 (29) 4 (44%) Age (years) 12 (14.4–5.6) 13.2 (17.7–8.1) 14 (15.5–9.4) 0.9 (5.9–0.2) BSA 1.2 (1.6–0.8) 1.4 (1.7–1) 1.3 (1.6–1) 0.4 (0.8–0.2) Diagnosis  Aortic stenosis 20 (40) 9 (47) 4 (19) 5 (56)  Aortic regurgitation 29 (59) 10 (53) 17 (81) 4 (44) ECC (min) 223 (261–189) 223 (262–190) 223 (269–181) 225 (286–190) Cross-clamp time (min) 125 (143–116) 125 (139–115) 120 (146–118) 128 (160–112) Length of intensive care unit stay (days) 2 (4–3) 2 (2.25–1) 2 (3.75–1.25) 6 (7–3) Length of hospital stay (days) 11 (14–9) 10 (13–9) 11 (11–9) 17 (32–10) Data are presented as n (%) or median (interquartile range). BSA: body surface area; ECC: extracorporeal circulation time. Table 1: Patient demographics, intraoperative and postoperative data Total (n = 49) No mismatch (n = 19) Reduction plasty (n = 21) Ross–Konno (n = 9) Gender  Male 37 (76) 17 (89) 15 (71) 5 (56%)  Female 12 (24) 2 (11) 6 (29) 4 (44%) Age (years) 12 (14.4–5.6) 13.2 (17.7–8.1) 14 (15.5–9.4) 0.9 (5.9–0.2) BSA 1.2 (1.6–0.8) 1.4 (1.7–1) 1.3 (1.6–1) 0.4 (0.8–0.2) Diagnosis  Aortic stenosis 20 (40) 9 (47) 4 (19) 5 (56)  Aortic regurgitation 29 (59) 10 (53) 17 (81) 4 (44) ECC (min) 223 (261–189) 223 (262–190) 223 (269–181) 225 (286–190) Cross-clamp time (min) 125 (143–116) 125 (139–115) 120 (146–118) 128 (160–112) Length of intensive care unit stay (days) 2 (4–3) 2 (2.25–1) 2 (3.75–1.25) 6 (7–3) Length of hospital stay (days) 11 (14–9) 10 (13–9) 11 (11–9) 17 (32–10) Total (n = 49) No mismatch (n = 19) Reduction plasty (n = 21) Ross–Konno (n = 9) Gender  Male 37 (76) 17 (89) 15 (71) 5 (56%)  Female 12 (24) 2 (11) 6 (29) 4 (44%) Age (years) 12 (14.4–5.6) 13.2 (17.7–8.1) 14 (15.5–9.4) 0.9 (5.9–0.2) BSA 1.2 (1.6–0.8) 1.4 (1.7–1) 1.3 (1.6–1) 0.4 (0.8–0.2) Diagnosis  Aortic stenosis 20 (40) 9 (47) 4 (19) 5 (56)  Aortic regurgitation 29 (59) 10 (53) 17 (81) 4 (44) ECC (min) 223 (261–189) 223 (262–190) 223 (269–181) 225 (286–190) Cross-clamp time (min) 125 (143–116) 125 (139–115) 120 (146–118) 128 (160–112) Length of intensive care unit stay (days) 2 (4–3) 2 (2.25–1) 2 (3.75–1.25) 6 (7–3) Length of hospital stay (days) 11 (14–9) 10 (13–9) 11 (11–9) 17 (32–10) Data are presented as n (%) or median (interquartile range). BSA: body surface area; ECC: extracorporeal circulation time. Twenty-one patients underwent a total of 51 procedures prior to the Ross or Ross–Konno procedure (Table 2). Table 2: Previous cardiac procedures Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Balloon dilatation AV 20 (41) 8 (42) 6 (29) 6 (67) AV-sparing repair 18 (37) 8 (42) 7 (33) 3 (33) Coarctation of the aorta repair 3 (6) 2 (11) 1 (5) Resection of the subvalvular aortic membrane 2 (4) 2 (22) Mitral valve reconstruction 2 (4) 1 (5) 1 (11) Tricuspidal valve reconstruction 1 (2) 1 (11) Closure of the ventricular septal defect 1 (2) 1 (11) Aortic root replacement (Konno) 1 (2) 1 (11) Reconstruction of the AV with homograft root replacement 1 (2) 1 (11) Reduction in the ascending aorta 1 (2) 1 (5) Closure of the atrial septal defect 1 (2) 1 (11) Total procedures 51 20 14 17 Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Balloon dilatation AV 20 (41) 8 (42) 6 (29) 6 (67) AV-sparing repair 18 (37) 8 (42) 7 (33) 3 (33) Coarctation of the aorta repair 3 (6) 2 (11) 1 (5) Resection of the subvalvular aortic membrane 2 (4) 2 (22) Mitral valve reconstruction 2 (4) 1 (5) 1 (11) Tricuspidal valve reconstruction 1 (2) 1 (11) Closure of the ventricular septal defect 1 (2) 1 (11) Aortic root replacement (Konno) 1 (2) 1 (11) Reconstruction of the AV with homograft root replacement 1 (2) 1 (11) Reduction in the ascending aorta 1 (2) 1 (5) Closure of the atrial septal defect 1 (2) 1 (11) Total procedures 51 20 14 17 AV: aortic valve. Table 2: Previous cardiac procedures Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Balloon dilatation AV 20 (41) 8 (42) 6 (29) 6 (67) AV-sparing repair 18 (37) 8 (42) 7 (33) 3 (33) Coarctation of the aorta repair 3 (6) 2 (11) 1 (5) Resection of the subvalvular aortic membrane 2 (4) 2 (22) Mitral valve reconstruction 2 (4) 1 (5) 1 (11) Tricuspidal valve reconstruction 1 (2) 1 (11) Closure of the ventricular septal defect 1 (2) 1 (11) Aortic root replacement (Konno) 1 (2) 1 (11) Reconstruction of the AV with homograft root replacement 1 (2) 1 (11) Reduction in the ascending aorta 1 (2) 1 (5) Closure of the atrial septal defect 1 (2) 1 (11) Total procedures 51 20 14 17 Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Balloon dilatation AV 20 (41) 8 (42) 6 (29) 6 (67) AV-sparing repair 18 (37) 8 (42) 7 (33) 3 (33) Coarctation of the aorta repair 3 (6) 2 (11) 1 (5) Resection of the subvalvular aortic membrane 2 (4) 2 (22) Mitral valve reconstruction 2 (4) 1 (5) 1 (11) Tricuspidal valve reconstruction 1 (2) 1 (11) Closure of the ventricular septal defect 1 (2) 1 (11) Aortic root replacement (Konno) 1 (2) 1 (11) Reconstruction of the AV with homograft root replacement 1 (2) 1 (11) Reduction in the ascending aorta 1 (2) 1 (5) Closure of the atrial septal defect 1 (2) 1 (11) Total procedures 51 20 14 17 AV: aortic valve. Echocardiographic data Two-dimensional echocardiography and colour-flow Doppler were obtained in all patients before surgery, immediately postoperatively, before hospital discharge and at least annually during the follow-up period. Left ventricular dimensions measured by m-mode and the aortic root dimensions measured on the level of the annulus and the sinotubular junction were reviewed. z-scores were calculated on the basis of expected normal aortic dimensions [7] and expected normal left ventricular dimensions [8] for body surface area. Aortic regurgitation was graded on a scale of 0–4 (none, trivial, mild, moderate and severe). Trivial aortic regurgitation was positioned in the analysis as Grade 0.5. Conduit dysfunction was defined as a transvalvular peak gradient exceeding 35 mmHg or a pulmonary regurgitation 2+ on echocardiography. For patients undergoing a reoperation for the LVOT or right ventricular outflow tract, the final echocardiography before the reoperation was used. Holter monitoring The Holter electrocardiogram, conducted on 45 (92%) patients, was performed within 1 year after the procedure to assess rhythm and conduction abnormalities. Operative procedure Operations were conducted through a median sternotomy with cardiopulmonary bypass at a perfusate temperature of 27.2±1.9°C (range 22–32°C). The Ross procedure was performed utilizing the root replacement technique as previously described [9]. In case of a size mismatch between the pulmonary valve and the aortic annulus, the neoaortic root was tailored with annular reduction plasty (n = 21) or enlargement (n = 9) if indicated. In the reduction plasty group, one or a combination of the following surgical techniques was employed to adjust the mismatch and to strengthen the aortic wall to avoid dilatation: purse-string stitches to strengthen the anterior sinus (n = 8), annulus strengthening of the non-coronary sinus using the remnants of the native aortic root (n = 6) and a reduction aortoplasty for mismatch of the ascending aorta with direct resection of a strip of the anterior wall (n = 17). In 9 (18%) patients with annular hypoplasia and LVOT obstruction, we performed the modified Ross–Konno procedure, including annulus division below the commissure between the left and the right coronary cusps with extensive septal myectomy, without creating a ventricular septum defect. To re-establish continuity between the right ventricle and pulmonary artery bifurcation pulmonary homografts (n = 24, mean diameter 22.2 ± 2.1 mm, range 18–26 mm), a bovine valved allograft (Contegra, n = 22, mean diameter 18.9 ± 3.5, range 12–22 mm), aortic homografts (n = 2, mean diameter 16 ± 1.4 mm, range 15–17 mm) or a Medtronic Freestyle valve (n = 1, diameter 25 mm) were implanted. Concomitant procedures are presented in Table 3. Table 3: Concomitant procedures Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Ligature of the patent ductus arteriosus 2 (4) 2 (22) Fenestration of atrial septal defect 1 (2) 1 (5) Closure of the ventricular septal defect 1 (2) 1 (11) Enlargement of the ascending aorta with a xenopericardial patch 1 (2) 1 (11) Mitral valve repair 3 (6) 1 (5) 1 (5) 1 (11) Enlargement of the pulmonary bifurcation with a xenopericardial patch 1 (2) 1 (11) Closure of the persistent foramen ovale 1 (2) 1 (5) Reduction in the pulmonary root with purse-string suture 1 (2) 1 (5) Enlargement of the proximal Contegra with a patch 1 (2) 1 (5) Xenopericardial patch on pulmonary Freestyle prosthesis 1 (2) 1 (5) Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Ligature of the patent ductus arteriosus 2 (4) 2 (22) Fenestration of atrial septal defect 1 (2) 1 (5) Closure of the ventricular septal defect 1 (2) 1 (11) Enlargement of the ascending aorta with a xenopericardial patch 1 (2) 1 (11) Mitral valve repair 3 (6) 1 (5) 1 (5) 1 (11) Enlargement of the pulmonary bifurcation with a xenopericardial patch 1 (2) 1 (11) Closure of the persistent foramen ovale 1 (2) 1 (5) Reduction in the pulmonary root with purse-string suture 1 (2) 1 (5) Enlargement of the proximal Contegra with a patch 1 (2) 1 (5) Xenopericardial patch on pulmonary Freestyle prosthesis 1 (2) 1 (5) Table 3: Concomitant procedures Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Ligature of the patent ductus arteriosus 2 (4) 2 (22) Fenestration of atrial septal defect 1 (2) 1 (5) Closure of the ventricular septal defect 1 (2) 1 (11) Enlargement of the ascending aorta with a xenopericardial patch 1 (2) 1 (11) Mitral valve repair 3 (6) 1 (5) 1 (5) 1 (11) Enlargement of the pulmonary bifurcation with a xenopericardial patch 1 (2) 1 (11) Closure of the persistent foramen ovale 1 (2) 1 (5) Reduction in the pulmonary root with purse-string suture 1 (2) 1 (5) Enlargement of the proximal Contegra with a patch 1 (2) 1 (5) Xenopericardial patch on pulmonary Freestyle prosthesis 1 (2) 1 (5) Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Ligature of the patent ductus arteriosus 2 (4) 2 (22) Fenestration of atrial septal defect 1 (2) 1 (5) Closure of the ventricular septal defect 1 (2) 1 (11) Enlargement of the ascending aorta with a xenopericardial patch 1 (2) 1 (11) Mitral valve repair 3 (6) 1 (5) 1 (5) 1 (11) Enlargement of the pulmonary bifurcation with a xenopericardial patch 1 (2) 1 (11) Closure of the persistent foramen ovale 1 (2) 1 (5) Reduction in the pulmonary root with purse-string suture 1 (2) 1 (5) Enlargement of the proximal Contegra with a patch 1 (2) 1 (5) Xenopericardial patch on pulmonary Freestyle prosthesis 1 (2) 1 (5) Statistical analysis Data are expressed as mean ± standard deviation and range or as median (interquartile range) for continuous variables and as count and percentage of patients for categorical variables. Statistical analysis was performed using SPSS 2010 (IBM Corp., Version 19.0. Armonk, NY, USA) and Microsoft Excel 2010. Overall survival and probability of freedom from reoperation and reintervention was estimated according to the Kaplan–Meier method. Univariable Cox proportional hazards regression was used to evaluate variables (the age at surgery, year of surgery and size of conduit material) as predictors for the right ventricular outflow tract reintervention. A comparison on conduit material (a homograft versus a Contegra conduit) was conducted using the log-rank test. Data were tested for normal distribution using the Anderson–Darling test. The F-test was used to check for the equality of variances prior to the Student’s t-test. Changes in aortic annulus z-score and left ventricular end-diastolic diameter (LVEDD) z-scores over time within the subgroups were analysed using a paired Student’s t-test. Comparisons among subgroups were performed using the 2-sample equal variances Student’s t-test. Changes of the aortic regurgitation grade within the groups have been analysed using the paired sign test, and the Kruskal–Wallis test was used to compare aortic regurgitation grades between the groups. The Fisher’s exact test was used to find out whether there is a correlation between the development of aortic valve regurgitation and aortic annulus root dilatation. A P-value <0.05 was considered statistically significant. Correction of multiple testing was not performed. Early mortality was defined as death within 30 days after the Ross or the Ross–Konno surgery or before discharge from the hospital. RESULTS Follow-up The mean follow-up for reintervention and reoperation was 4.6 ± 2.7 years (9 days to 9.2 years). The inclusion criteria for echocardiographic follow-up was the existence of an echocardiogram for at least 1 year or more after the procedure. The echocardiographic follow-up for aortic regurgitation, aortic annulus, aortic root and LVEDD measurements were reported in 42 (86%), 35 (71%), 24 (49%) and 38 (78%) patients with a mean follow up of 5.3 ± 2.3 (1.1 to 9.2) years, 5.1 ± 2.4 (1.1 to 9.2) years, 5.6 ± 1.7 (3 to 9.2) years and 5.2 ± 2.3 (1.1 to 9.2) years, respectively. Mortality There was no early death. The overall mortality was 6%. Two patients died for cardiac reasons (4%). The cause of death remained unknown in 1 patient. One patient died 6 months after the modified Ross–Konno procedure with a severe pulmonary hypertension at the age of 10 months. The last echocardiography 2 days before death showed a severe persistent pulmonary hypertension with a reduced right ventricular contractility and severe dilated liver and cava inferior veins; the homograft and autograft showed trivial regurgitation without evidence of stenosis. The second death occurred because of acutely decompensated right heart failure 19 months after the modified Ross–Konno operation, which had been performed at the age of 1 month. The last echocardiography showed an eccentric severe right ventricular hypertrophy and a severe hypertrophic hypoplastic left ventricle with massive endomyocardial fibrosis and pulmonary hypertension, which were already described before the modified Ross–Konno procedure. The third death occurred for an unspecified reason 47 months after the Ross operation (no mismatch group), which was performed at the age of 17 years due to combined aortic valve failure. Overall survival estimated using the Kaplan–Meier analysis was 92 ± 4% at the 4-year follow-up (Fig. 1). Figure 1: View largeDownload slide Kaplan–Meier survival curves. Figure 1: View largeDownload slide Kaplan–Meier survival curves. Complications Intraoperative complications were as follows: rhythm disturbances included junctional tachycardia in 2 patients and recurrent ventricular fibrillation with intraoperative atrioventricular (AV)-Block III requiring 4 rounds of defibrillation and a temporary pacemaker in another patient. One patient needed intraoperative coronary artery bypass due to injury of the right coronary artery. In the early postoperative period (defined by the time from post-procedure to discharge) complications were as follows: 1 patient with pulmonary embolism due to activated protein C (APC) resistance (heterozygous factor V Leiden mutation). One patient had post-pump chorea. Delayed complications included 2 cases of autograft endocarditis. In 1 case, there was a successful response to conservative treatment, and surgical treatment was administered in the other. See Table 4 for details. Table 4: Complications, reinterventions and surgeries Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Intraoperative complications  Myocardial infarction 1 (2) 1 (5)  Rhythm disturbances 3 (6) 1 (5) 2 (22) Early postoperative/before discharge  Pulmonary embolism 1 (2) 1 (5)  Left ventricular dysfunction 2 (4) 1 (5) 1 (5)  Post-pump chorea 1 (2) 1 (11) Late postoperative  Endocarditis 2 (4) 1 (5) 1 (5) Reinterventions/resurgeries of the right ventricular outflow tract  Balloon dilatation 6 (12) 2 (10) 1 (5) 3 (33)  Percutaneous pulmonary valve replacement 3 (6) 2 (10) 1 (11)  Conduit replacement and posterior plastic bifurcation pulmonary arteries 1 (2) 1 (11)  Stent pulmonary root 1 (2) 1 (5) Reintervention/resurgery of the left ventricular outflow tract  Abscess debridement of the aortic valve and aortic valve replacement 1 (2) 1 (5) Others  Mitral valve repair 2 (4) 1 (11)  Mechanical mitral valve replacement 1 (2) 1 (5)  Pacemaker 1 (2) 1 (11)  Coronary artery bypass graft 1 (2) 1 (5) Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Intraoperative complications  Myocardial infarction 1 (2) 1 (5)  Rhythm disturbances 3 (6) 1 (5) 2 (22) Early postoperative/before discharge  Pulmonary embolism 1 (2) 1 (5)  Left ventricular dysfunction 2 (4) 1 (5) 1 (5)  Post-pump chorea 1 (2) 1 (11) Late postoperative  Endocarditis 2 (4) 1 (5) 1 (5) Reinterventions/resurgeries of the right ventricular outflow tract  Balloon dilatation 6 (12) 2 (10) 1 (5) 3 (33)  Percutaneous pulmonary valve replacement 3 (6) 2 (10) 1 (11)  Conduit replacement and posterior plastic bifurcation pulmonary arteries 1 (2) 1 (11)  Stent pulmonary root 1 (2) 1 (5) Reintervention/resurgery of the left ventricular outflow tract  Abscess debridement of the aortic valve and aortic valve replacement 1 (2) 1 (5) Others  Mitral valve repair 2 (4) 1 (11)  Mechanical mitral valve replacement 1 (2) 1 (5)  Pacemaker 1 (2) 1 (11)  Coronary artery bypass graft 1 (2) 1 (5) Table 4: Complications, reinterventions and surgeries Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Intraoperative complications  Myocardial infarction 1 (2) 1 (5)  Rhythm disturbances 3 (6) 1 (5) 2 (22) Early postoperative/before discharge  Pulmonary embolism 1 (2) 1 (5)  Left ventricular dysfunction 2 (4) 1 (5) 1 (5)  Post-pump chorea 1 (2) 1 (11) Late postoperative  Endocarditis 2 (4) 1 (5) 1 (5) Reinterventions/resurgeries of the right ventricular outflow tract  Balloon dilatation 6 (12) 2 (10) 1 (5) 3 (33)  Percutaneous pulmonary valve replacement 3 (6) 2 (10) 1 (11)  Conduit replacement and posterior plastic bifurcation pulmonary arteries 1 (2) 1 (11)  Stent pulmonary root 1 (2) 1 (5) Reintervention/resurgery of the left ventricular outflow tract  Abscess debridement of the aortic valve and aortic valve replacement 1 (2) 1 (5) Others  Mitral valve repair 2 (4) 1 (11)  Mechanical mitral valve replacement 1 (2) 1 (5)  Pacemaker 1 (2) 1 (11)  Coronary artery bypass graft 1 (2) 1 (5) Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Intraoperative complications  Myocardial infarction 1 (2) 1 (5)  Rhythm disturbances 3 (6) 1 (5) 2 (22) Early postoperative/before discharge  Pulmonary embolism 1 (2) 1 (5)  Left ventricular dysfunction 2 (4) 1 (5) 1 (5)  Post-pump chorea 1 (2) 1 (11) Late postoperative  Endocarditis 2 (4) 1 (5) 1 (5) Reinterventions/resurgeries of the right ventricular outflow tract  Balloon dilatation 6 (12) 2 (10) 1 (5) 3 (33)  Percutaneous pulmonary valve replacement 3 (6) 2 (10) 1 (11)  Conduit replacement and posterior plastic bifurcation pulmonary arteries 1 (2) 1 (11)  Stent pulmonary root 1 (2) 1 (5) Reintervention/resurgery of the left ventricular outflow tract  Abscess debridement of the aortic valve and aortic valve replacement 1 (2) 1 (5) Others  Mitral valve repair 2 (4) 1 (11)  Mechanical mitral valve replacement 1 (2) 1 (5)  Pacemaker 1 (2) 1 (11)  Coronary artery bypass graft 1 (2) 1 (5) Reoperation of the left ventricular outflow tract Only 1 autograft reoperation was carried out. The patient had autograft endocarditis with paravalvular abscess 5 weeks after the Ross operation (reduction plasty group) as a result of an infected sacral dermoid, followed by operative paravalvular abscess debridement. Six years after the Ross procedure, the same patient developed progressive dilatation of the aortic valve root (50 mm) with pseudoaneurysm of the posterior aortic valve annulus and severe aortic regurgitation. The ascending aorta showed no dilatation. Correction of the pseudoaneurysm was performed by the U stich suture. Because of the altered anatomy after the aneurysm correction, a valve-sparing root replacement (Tirone David) failed, and AVR (a 29-mm Medtronic Freestyle valve) was inevitable (Table 4). Autograft and left ventricular function and dimensions At the last follow-up, mean z-scores at the annular level were 2.1 ± 1.7 in the no mismatch group, 2.5 ± 1.6 in the reduction plasty group and 3.6 ± 1.6 in the Ross–Konno group. An aortic annulus z-score >2 was found in 58% (no mismatch group), 50% (reduction plasty group) and 83% of patients (Ross–Konno group). A comparison between discharge and follow-up within the subgroups revealed a significant change over time of the aortic annulus z-score in the Ross–Konno group (P = 0.03) but not in the no mismatch or reduction plasty group. A comparison between the subgroups at discharge and the latest follow-up disclosed no significant differences in aortic annulus z-scores. In the overall cohort, the increase in aortic annulus was 0.1 cm/year, analogous to an increase in z-scores by 0.24/year (no mismatch group), 0.21/year (reduction plasty group) and 0.34/year (Ross–Konno group). z-scores over time are shown in Fig. 2. Figure 2: View largeDownload slide Aortic annulus z-score shift over time. The bottom and top edges of the box are 25th percentile and 75th percentile, respectively, and the central mark indicates the median. The end of the whiskers represent minimum and maximum values. Figure 2: View largeDownload slide Aortic annulus z-score shift over time. The bottom and top edges of the box are 25th percentile and 75th percentile, respectively, and the central mark indicates the median. The end of the whiskers represent minimum and maximum values. The mean aortic root diameter at sinotubular junction and z-score were 3.7 ± 0.7 cm (range 2.3–5) and 2.8 ± 1 (0.9–5), corresponding to a z-score of 2.8 ± 1 (1.5–4.8) (no mismatch group), 3 ± 1.2 (0.9–5) (reduction plasty group) and 2.4 ± 0.9 (1.5–4) (Ross–Konno group). A dilatation of the aortic root (defined as a z-score >2) was diagnosed in 9 (82%) patients in the no mismatch group, in 7 patients (88%) in the reduction plasty group and in 4 (80%) patients in the Ross–Konno group. At the latest follow-up, 93% of the patients had none-to-mild aortic valve regurgitation. One patient with severe aortic regurgitation and an aortic root measuring 5 cm required an AVR (see above). Another 2 patients with aortic root diameters of 4.7 cm and concomitant regurgitation are in stable clinical condition. In general, the aortic regurgitation grade grew slowly (0.04 ± 1.6 grades/year) without reaching statistical significance (P = 0.36). Twenty-three (55%) of the patients maintained the same aortic regurgitation grade from discharge to the last follow-up, 12 (29%) improved and 7 (17%) worsened. Comparison within the subgroups during follow-up and between subgroups at discharge and follow-up revealed no significant increase or differences of aortic regurgitation grade. The grade distribution of aortic regurgitation over time is shown in Fig. 3. Figure 3: View largeDownload slide Aortic regurgitation (AR) grade shift over time. Figure 3: View largeDownload slide Aortic regurgitation (AR) grade shift over time. There is no correlation between the development of aortic regurgitation and aortic annulus root dilatation (P = 0.61). Forty-five (92%) patients had no LVOT obstruction, and 2 (4%) patients had trivial autograft stenosis. The echocardiographic outcome of left ventricular dimensions is shown in Fig. 4. After an initial postoperative decline of the LVEDD z-scores, we observed a significant increase within the no mismatch (P = 0.013) and reduction plasty groups (P = 0.023) during follow-up. Nevertheless, measurements and z-scores were within normal range in all groups at the latest follow-up; LVEDD z-scores were 0.2 ± 1.5 (−2.6 to 2.6) (no mismatch group), 0.7 ± 1.1 (−1.3 to 3) (reduction plasty group) and 0.6 ± 1.2 (−1.4 to 2.6) (Ross–Konno group). Figure 4: View largeDownload slide Left ventricular end-diastolic diameter (LVEDD) z-score shift over time. Figure 4: View largeDownload slide Left ventricular end-diastolic diameter (LVEDD) z-score shift over time. Comparison within the Ross–Konno group and between the subgroups at discharge and follow-up showed no significant differences in z-scores. The mean ejection fraction was 61 ± 7% (range 50–78%), without significant differences between the subgroups. Reintervention and reoperation of the right ventricular outflow tract During follow-up 6 (12%), patients underwent right ventricle and pulmonary artery graft reintervention or reoperation within a mean interval time of 2.6 ± 1.9 (range 0.7–5.4) years (Table 4). Right ventricle and pulmonary artery conduit stenosis was the leading cause of all. Univariate risk factors for reinterventions were: the use of a Contegra conduit (P = 0.027), younger age (P = 0.019) and smaller conduit size (P = 0.023). Overall freedom from the right ventricular outflow tract reintervention and reoperation was 90 ± 5% at 2.5 years. Holter monitor One patient (Ross–Konno group) showed a postoperative left bundle branch block with severe mitral valve regurgitation and needed a pacemaker implantation 8 months after the procedure. DISCUSSION It is common knowledge that the Ross procedure is a reproducible and durable procedure. There is further ongoing critical analysis of specific techniques and their relationship to specific event rates from the German–Dutch Ross Registry, which now includes 1779 adult patients from 8 participating centres, spanning 24 years [10], and from the Italian Paediatric Ross Registry, including 305 children, spanning 23 years [5]. To our knowledge, this study is focusing for the first time on additional surgical modifications to the root technique at the annular level in children—such as the modified Konno incision or reduction plasty to correct autograft–aortic mismatch—and their effect on the structural and functional quality of the autograft at a clinical follow-up of 5 years. Based on published data, overall survival for the standard Ross procedure is described as 93.9% at 5 years [11] and 96%, 90.4% and 95% at 10 years [11–13]. Our data confirm these findings, with freedom from mortality of 91.9% at 4-year follow-up. Two of the 3 deaths occurred in the Ross–Konno group. These 2 patients were aged 1 month and 10 month at the time of the operation with a higher mortality risk according to Brown et al. [14], who showed that age less than 1 year was the most sensitive predictor of mortality of patients undergoing the Ross–Konno procedure. Nelson et al. [15] not only observed higher mortality rates for infants after the Ross Procedures but also showed excellent long-term autograft durability in the same group. In general, controversies linger mainly because the Ross procedure puts 2 valves at risk. This might increase the number of reoperations and interventions owing to degeneration of the homograft or autograft failure [11, 16]. Whether the postoperative increase in the aortic annulus root size is due to somatic growth or pathological remodelling with disproportionate dilatation is still under discussion [17]. Excessive dilatation and autograft failure would lead to aortic valve regurgitation [18, 19]. In this cohort, the need for reintervention on the autograft was limited. During a mean follow-up of 4.6 years, only 1 patient required reoperation on the autograft. In previously published articles, freedom from autograft reinterventions is described as 97% at 5 years [20], 74%, 80% and 86% at 10 years [5, 12, 20] and 75% at 15 years [5]. Hörer et al. [11] published more favourable results in their study containing 152 paediatric patients from the German Ross Registry, with freedom from reoperation of the autograft of 99% at 5 years and 95.5% at 10 years. Prior endocarditis, prior aortic regurgitation and a longer follow-up period emerged as risk factors [11]. As related to autograft structure, in the majority of cases, the neoaortic valve at the annular level grew in a manner that reflected normal somatic proportions in the no mismatch and reduction plasty groups but not in the Ross–Konno group. Although the increase in the entire cohort was 0.1 cm/year, the z-score of the aortic annulus in the modified Ross–Konno group was already larger before discharge: therefore, a further increase led to noticeable growth beyond the usual limits. Nevertheless, diameters and z-scores of the sinotubular junction were smaller in the modified Ross–Konno group. Additionally, normalization of left ventricular dimensions after the procedure, as indicated in previous studies [12, 13, 17, 21], along with the ejection fraction obtained are proof that the left ventricular function was preserved. In contrast to Frigiola et al. [12], we found a sizable but slow increase in LVEDD over time. Nevertheless, all measurements fell within the normal range at the final follow-up. The mean aortic root diameter was 37 ± 7 mm (range 23–50 mm), yielding a z-score of 2.8 ± 1 (0.9–5) at the latest follow-up. Analogous results are stated in the literature with mean aortic root diameters varying between 35 and 37 mm [13, 21–23]. The comparability of the echocardiographic findings, according to diameters and z-scores, concerning the occurrence of dilatation is limited because the definition of dilatation differs. Based on the definition that a z-score >2 equates to more than the 95th percentile, we found 83% of patients meeting this criterion and confirming a dilatation of the aortic root in previous observations with 52% [24], 64% [13], 75% [25] and 90% [22]. Another method for specifying autograft function, which additionally considers different follow-up times, was used by Pasquali et al. [17], Hörer et al. [19] and Frigiola et al. [12]. They analysed the change in aortic root dimensions in cm per year and found a significant increase in the size of the aortic root at the level of the sinus of Valsalva (0.1–0.5 cm/year) and the sinotubular junction (0.08–0.7 cm/year). Frigiola et al. [12] and Pasquali et al. [17] described no direct association between neoaortic root dilatation and neoaortic regurgitation, whereas Hörer et al. [19] showed significant evidence that aortic regurgitation increases the sinotubular junction diameter (P = 0.028). Despite aortic root dilation (defined as a z-score >2), in 83% of our study population, the development of higher grade aortic valve regurgitation was exceptional, with only 3 of 45 (7%) patients showing more than mild autograft regurgitation. Analogous findings are outlined by Clark et al. [21] and El Behery et al. [13]. Our results are in line with Frigiola et al. [12] and Pasquali et al. [17], revealing no significant correlation of neoaortic root dilatation and progress of autograft regurgitation (P = 0.61). Risk factors for the development of aortic regurgitation described by others are the degree of aortic regurgitation at discharge [12], prior AVR (P = 0.002) and prior ventricular septal defect repair (P = 0.02) [17]. Hörer et al. [19] found a gradual but significant increase in the grade of aortic regurgitation with follow-up time (0.06 ± 0.02 grades per year, P < 0.001) [20]. We can confirm an even lower increase in regurgitation grade (0.04 ± 0.16 grades/year) without reaching statistical significance (P = 0.36). The impact of this finding remains unknown since none of these patients had a grade of more than mild aortic regurgitation at the final follow-up. Therefore, a longer follow-up is needed. Limitations The limitations of the study are the small cohort and the retrospective design. CONCLUSION In our patient cohort, overall mortality, reoperation and reintervention rates were low. The autograft function showed guaranteed results at the mid-term follow-up. Despite the fact that we observed a larger size of aortic annulus diameter over time when compared with healthy children, the occurrence of aortic regurgitation and the need for reintervention were very low. The incidence of neoaortic valve dysfunction and the need for reintervention may increase over time, especially in the Ross–Konno group; therefore, additional observation is required. In conclusion, surgical modifications (e.g. modified Konno procedure to enlarge LVOT and reduction plasty) at the annular level during a Ross procedure do not negatively influence the structure and function of the autograft at the mid-term follow-up. Conflict of interest: none declared. REFERENCES 1 Ross DN. Replacement of aortic and mitral valves with a pulmonary autograft . Lancet 1967 ; 290 : 956 – 8 . Google Scholar CrossRef Search ADS 2 Elkins RC , Knott-Craig CJ , Ward KE , McCue C , Lane MM. Pulmonary autograft in children: realized growth potential . Ann Thorac Surg 1994 ; 57 : 1387 – 93 . Google Scholar CrossRef Search ADS PubMed 3 Brown JW , Patel PM , Ivy Lin JH , Habib AS , Rodefeld MD , Turrentine MW. Ross versus non-ross aortic valve replacement in children: a 22-year single institution comparison of outcomes . Ann Thorac Surg 2016 ; 101 : 1804 – 10 . Google Scholar CrossRef Search ADS PubMed 4 Ross D , Jackson M , Davies J. The pulmonary autograft—a permanent aortic valve . Eur J Cardiothorac Surg 1992 ; 6 : 113 – 6 . Google Scholar CrossRef Search ADS PubMed 5 Luciani GB , Lucchese G , Carotti A , Brancaccio G , Abbruzzese P , Caianiello G et al. Two decades of experience with the Ross operation in neonates, infants and children from the Italian Paediatric Ross Registry . Heart 2014 ; 100 : 1954 – 9 . Google Scholar CrossRef Search ADS PubMed 6 Sharabiani MT , Dorobantu DM , Mahani AS , Turner M , Peter Tometzki AJ , Angelini GD et al. Aortic valve replacement and the Ross operation in children and young adults . J Am Coll Cardiol 2016 ; 67 : 2858 – 70 . Google Scholar CrossRef Search ADS PubMed 7 Pettersen MD , Du W , Skeens ME , Humes RA. Regression equations for calculation of z-scores of cardiac structures in a large cohort of healthy infants, children, and adolescents: an echocardiographic study . J Am Soc Echocardiogr 2008 ; 21 : 922 – 34 . Google Scholar CrossRef Search ADS PubMed 8 Kampmann C , Wiethoff CM , Wenzel A , Stolz G , Betancor M , Wippermann CF et al. Normal values of M-mode echocardiographic measurements of more than 2000 healthy infants and children in central Europe . Heart 2000 ; 83 : 667 – 72 . Google Scholar CrossRef Search ADS PubMed 9 Spray TL. Technique of pulmonary autograft aortic valve replacement in children (the Ross procedure) . Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu 1998 ; 1 : 165 – 78 . Google Scholar CrossRef Search ADS PubMed 10 Sievers HH , Stierle U , Charitos EL , Takkenberg JJ , Hörer J , Lange R et al. A multicentre evaluation of the autograft procedure for young patients undergoing aortic valve replacement: update on the German Ross Registry . Eur J Cardiothorac Surg 2016 ; 49 : 212 – 8 . Google Scholar CrossRef Search ADS PubMed 11 Hörer J , Stierle U , Bogers AJ , Rein JG , Hetzer R , Sievers HH et al. Re-interventions on the autograft and the homograft after the Ross operation in children . Eur J Cardiothorac Surg 2010 ; 37 : 1008 – 14 . Google Scholar CrossRef Search ADS PubMed 12 Frigiola A , Varrica A , Satriano A , Giamberti A , Pomè G , Abella R. Neoaortic valve and root complex evolution after Ross operation in infants, children, and adolescents . Ann Thorac Surg 2010 ; 90 : 1278 – 85 . Google Scholar CrossRef Search ADS PubMed 13 El Behery S , Rubay J , Sluysmans T , Absil B , Ovaert C. Midterm results of the Ross procedure in a pediatric population: bicuspid aortic valve is not a contraindication . Pediatr Cardiol 2009 ; 30 : 219 – 24 . Google Scholar CrossRef Search ADS PubMed 14 Brown JW , Ruzmetov M , Vijay P , Rodefeld MD , Turrentine MW. The Ross-Konno procedure in children: outcomes, autograft and allograft function, and reoperations . Ann Thorac Surg 2006 ; 82 : 1301 – 6 . Google Scholar CrossRef Search ADS PubMed 15 Nelson JS , Pasquali SK , Pratt CN , Yu S , Donohue JE , Loccoh E et al. Long-term survival and reintervention after the Ross procedure across the pediatric age spectrum . Ann Thorac Surg 2015 ; 99 : 2086 – 94. Google Scholar CrossRef Search ADS PubMed 16 Elkins RC , Thompson DM , Lane MM , Elkins CC , Peyton MD. Ross operation: 16-year experience . J Thorac Cardiovasc Surg 2008 ; 136 : 623 – 30; 630.e1–5. Google Scholar CrossRef Search ADS PubMed 17 Pasquali SK , Cohen MS , Shera D , Wernovsky G , Spray TL , Marino BS. The relationship between neo-aortic root dilation, insufficiency, and reintervention following the Ross procedure in infants, children, and young adults . J Am Coll Cardiol 2007 ; 49 : 1806 – 12 . Google Scholar CrossRef Search ADS PubMed 18 Valeske K , Müller M , Hijjeh N , Bauer J , Böning A , Schranz D et al. The fate of the pulmonary autograft in the aortic position: experience and results of 98 patients in twelve years . Thorac Cardiovasc Surg 2010 ; 58 : 334 – 8 . Google Scholar CrossRef Search ADS PubMed 19 Hörer J , Hanke T , Stierle U , Takkenberg JJ , Bogers AJ , Hemmer W et al. Neoaortic root diameters and aortic regurgitation in children after the Ross operation . Ann Thorac Surg 2009 ; 88 : 594 – 600 . Google Scholar CrossRef Search ADS PubMed 20 Brancaccio G , Polito A , Hoxha S , Gandolfo F , Giannico S , Amodeo A et al. The Ross procedure in patients aged less than 18 years: the midterm results . J Thorac Cardiovasc Surg 2014 ; 147 : 383 – 8 . Google Scholar CrossRef Search ADS PubMed 21 Clark JB , Pauliks LB , Rogerson A , Kunselman AR , Myers JL. The Ross operation in children and young adults: a fifteen-year, single-institution experience . Ann Thorac Surg 2011 ; 91 : 1936 – 41. Google Scholar CrossRef Search ADS PubMed 21 Hazekamp MG , Grotenhuis HB , Schoof PH , Rijlaarsdam ME , Ottenkamp J , Dion RA. Results of the Ross operation in a pediatric population . Eur J Cardiothorac Surg 2005 ; 27 : 975 – 9 . Google Scholar CrossRef Search ADS PubMed 23 Piccardo A , Ghez O , Gariboldi V , Riberi A , Collart F , Kreitmann B et al. Ross and Ross-Konno procedures in infants, children and adolescents: a 13-year experience . J Heart Valve Dis 2009 ; 18 : 76 – 82. Google Scholar PubMed 24 Kirkpatrick E , Hurwitz R , Brown J. A single center's experience with the Ross procedure in pediatrics . Pediatr Cardiol 2008 ; 29 : 894 – 900 . Google Scholar CrossRef Search ADS PubMed 25 Kalavrouziotis G , Raja S , Ciotti G , Karunaratne A , Corno AF , Pozzi M. Medium-term results from pulmonary autografts after the Ross procedure in children and adolescents . Hellenic J Cardiol 2006 ; 47 : 337 – 43 . Google Scholar PubMed © The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Interactive CardioVascular and Thoracic Surgery Oxford University Press

Do surgical modifications at the annular level during the Ross procedure negatively influence the structural and functional durability of the autograft?

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Oxford University Press
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© The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
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1569-9293
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Abstract

Abstract OBJECTIVES Do surgical modifications at the annular level (e.g. the modified Ross–Konno procedure or reduction plasty) influence the structure and function of the Ross autograft at the mid-term follow-up? METHODS From June 2001 to July 2009, 49 patients (37 men and 12 women), mean age 10.5 ± 5.7 years (range 2 weeks to 17.8 years), underwent Ross operations. Twenty-one patients underwent additional aortic annulus reduction plasty and 9 patients a modified Ross–Konno procedure. The need for reintervention, reoperation and valve function were retrospectively analysed for a mean follow-up of 4.6 ± 2.7 years (range 9 days to 9.2 years). RESULTS There were no intraoperative or early death. Three late deaths occurred. Survival at 4 years was 91.9 ± 4.6%. In the overall cohort, aortic annular growth was 1 mm/year, corresponding to a z-score increase of 0.24/year (no mismatch group), 0.21/year (reduction plasty group) and 0.34/year (Ross–Konno group). At the last follow-up, sinotubular junction z-scores were 2.8 ± 1, 3 ± 1 and 2.4 ± 0.9 in the no mismatch, reduction plasty, and Ross–Konno groups, respectively. Ninety-three percent of patients presented with none-to-mild autograft valve regurgitation. The Ross–Konno group showed a significant increase in aortic annulus size (z-score of the annulus at the last follow-up 3.6 ± 1.6; P = 0.036). The no mismatch and the reduction plasty groups showed z-scores within the normal range (2.1 ± 1.7 and 2.5 ± 1.6, respectively). CONCLUSIONS Additional aortic annulus reduction or enlargement does not disturb the structural and functional durability of the autograft at the mid-term follow-up. Long-term autograft integrity, especially in the Ross–Konno group, remains to be investigated. Ross procedure , Children , Modified Ross–Konno procedure , Aortic annulus , Left ventricular outflow tract , Echocardiography INTRODUCTION Aortic valve replacement (AVR) in adults using the pulmonary autograft was first described by Ross in 1967 [1]. Since then, the procedure has advanced and is now considered to be the AVR of choice in the paediatric population, including neonates and infants, due to the advantages of the avoidance of long-term anticoagulation, haemodynamic stability and the somatic growth potential of the autograft [2–4]. The results by Luciani’s et al. [5] on the use of the Ross operation in neonates, infants and children from the Italian Paediatric Ross Registry have recently been published. This study not only assesses survival and reoperation rates but also gives us additional meaningful data regarding the long-term structural and functional durability of the pulmonary autograft for 2 decades. A recently published retrospective study, involving 1501 children and young adults, comparing the Ross procedure and alternative AVR procedures (mechanical AVR, homograft AVR and bioprothesis AVR) shows that Ross patients had the highest event-free probability (death or any interventions at 10 years) [6]. Up until now, to our knowledge, only few published data are available with specific emphasis on surgical factors that might change the geometry of the junction portion between the left ventricular outflow tract (LVOT) and the neoaorta. In this article, we describe our experience with 49 children successively undergoing the Ross or the Ross–Konno procedure. Some of these patients underwent an additional surgery such as the modified Konno incision to enlarge the LVOT or reduction plasty at the annular or supra-annular level to correct autograft mismatch. The aim of this study was to determine whether these surgical manipulations which exceed the procedural requirements for the root replacement technique may lead to malfunction of the autograft or impede the somatic growth potential at the annular level when compared with the size-matched autograft at the mid-term follow-up. Therefore, we assessed the clinical and diagnostic results at the mid-term follow-up to evaluate autograft somatic growth, as well as haemodynamics, the need for reintervention or resurgery, heart rhythm and incidence of conduction disturbance after the procedure. PATIENTS AND METHODS Patient population All patients younger than 18 years who underwent a Ross or a Ross–Konno procedure between June 2001 and July 2009 at the University Hospital Zurich were enrolled in this study. Data were obtained from the cardiac surgery database, from medical records and from referring cardiologists with regard to the initial clinical features, surgical intervention and postoperative outcomes. There were 49 Ross procedures identified. For the purpose of this study, we divided the population into 3 groups. The no mismatch group (n = 19) underwent a Ross procedure as a full root technique, the reduction plasty group (n = 21) received a Ross procedure with a concomitant annulus reduction plasty and the 3rd group (n = 9) had a modified Ross–Konno procedure, including enlargement of the aortic annulus. The preoperative surgical indication for the procedure was aortic regurgitation for 29 (59%) patients and stenosis for 20 (59%) patients. Patients with both aortic stenosis and regurgitation were classified according to the predominant lesion. The underlying pathology was congenital aortic valve disease in all except 1 patient with aortic regurgitation caused by endocarditis. Bicuspid valve morphology was found in 63% of all cases. The mean age at operation was 10.5 ± 5.6 years (range 2 weeks to 17.8 years) including 2 neonates (Ross–Konno group) and 4 infants (3 Ross–Konno group and 1 reduction plasty group). Among the 49 operations, 2 were seen as emergency interventions due to congenital combined aortic valve disease with progressive cardiac failure (1 primary Ross surgery at the age of 5 weeks and 1 secondary Ross–Konno procedure at the age of 4 weeks s/p balloon dilatation). Patient demographics are given in Table 1. Table 1: Patient demographics, intraoperative and postoperative data Total (n = 49) No mismatch (n = 19) Reduction plasty (n = 21) Ross–Konno (n = 9) Gender  Male 37 (76) 17 (89) 15 (71) 5 (56%)  Female 12 (24) 2 (11) 6 (29) 4 (44%) Age (years) 12 (14.4–5.6) 13.2 (17.7–8.1) 14 (15.5–9.4) 0.9 (5.9–0.2) BSA 1.2 (1.6–0.8) 1.4 (1.7–1) 1.3 (1.6–1) 0.4 (0.8–0.2) Diagnosis  Aortic stenosis 20 (40) 9 (47) 4 (19) 5 (56)  Aortic regurgitation 29 (59) 10 (53) 17 (81) 4 (44) ECC (min) 223 (261–189) 223 (262–190) 223 (269–181) 225 (286–190) Cross-clamp time (min) 125 (143–116) 125 (139–115) 120 (146–118) 128 (160–112) Length of intensive care unit stay (days) 2 (4–3) 2 (2.25–1) 2 (3.75–1.25) 6 (7–3) Length of hospital stay (days) 11 (14–9) 10 (13–9) 11 (11–9) 17 (32–10) Total (n = 49) No mismatch (n = 19) Reduction plasty (n = 21) Ross–Konno (n = 9) Gender  Male 37 (76) 17 (89) 15 (71) 5 (56%)  Female 12 (24) 2 (11) 6 (29) 4 (44%) Age (years) 12 (14.4–5.6) 13.2 (17.7–8.1) 14 (15.5–9.4) 0.9 (5.9–0.2) BSA 1.2 (1.6–0.8) 1.4 (1.7–1) 1.3 (1.6–1) 0.4 (0.8–0.2) Diagnosis  Aortic stenosis 20 (40) 9 (47) 4 (19) 5 (56)  Aortic regurgitation 29 (59) 10 (53) 17 (81) 4 (44) ECC (min) 223 (261–189) 223 (262–190) 223 (269–181) 225 (286–190) Cross-clamp time (min) 125 (143–116) 125 (139–115) 120 (146–118) 128 (160–112) Length of intensive care unit stay (days) 2 (4–3) 2 (2.25–1) 2 (3.75–1.25) 6 (7–3) Length of hospital stay (days) 11 (14–9) 10 (13–9) 11 (11–9) 17 (32–10) Data are presented as n (%) or median (interquartile range). BSA: body surface area; ECC: extracorporeal circulation time. Table 1: Patient demographics, intraoperative and postoperative data Total (n = 49) No mismatch (n = 19) Reduction plasty (n = 21) Ross–Konno (n = 9) Gender  Male 37 (76) 17 (89) 15 (71) 5 (56%)  Female 12 (24) 2 (11) 6 (29) 4 (44%) Age (years) 12 (14.4–5.6) 13.2 (17.7–8.1) 14 (15.5–9.4) 0.9 (5.9–0.2) BSA 1.2 (1.6–0.8) 1.4 (1.7–1) 1.3 (1.6–1) 0.4 (0.8–0.2) Diagnosis  Aortic stenosis 20 (40) 9 (47) 4 (19) 5 (56)  Aortic regurgitation 29 (59) 10 (53) 17 (81) 4 (44) ECC (min) 223 (261–189) 223 (262–190) 223 (269–181) 225 (286–190) Cross-clamp time (min) 125 (143–116) 125 (139–115) 120 (146–118) 128 (160–112) Length of intensive care unit stay (days) 2 (4–3) 2 (2.25–1) 2 (3.75–1.25) 6 (7–3) Length of hospital stay (days) 11 (14–9) 10 (13–9) 11 (11–9) 17 (32–10) Total (n = 49) No mismatch (n = 19) Reduction plasty (n = 21) Ross–Konno (n = 9) Gender  Male 37 (76) 17 (89) 15 (71) 5 (56%)  Female 12 (24) 2 (11) 6 (29) 4 (44%) Age (years) 12 (14.4–5.6) 13.2 (17.7–8.1) 14 (15.5–9.4) 0.9 (5.9–0.2) BSA 1.2 (1.6–0.8) 1.4 (1.7–1) 1.3 (1.6–1) 0.4 (0.8–0.2) Diagnosis  Aortic stenosis 20 (40) 9 (47) 4 (19) 5 (56)  Aortic regurgitation 29 (59) 10 (53) 17 (81) 4 (44) ECC (min) 223 (261–189) 223 (262–190) 223 (269–181) 225 (286–190) Cross-clamp time (min) 125 (143–116) 125 (139–115) 120 (146–118) 128 (160–112) Length of intensive care unit stay (days) 2 (4–3) 2 (2.25–1) 2 (3.75–1.25) 6 (7–3) Length of hospital stay (days) 11 (14–9) 10 (13–9) 11 (11–9) 17 (32–10) Data are presented as n (%) or median (interquartile range). BSA: body surface area; ECC: extracorporeal circulation time. Twenty-one patients underwent a total of 51 procedures prior to the Ross or Ross–Konno procedure (Table 2). Table 2: Previous cardiac procedures Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Balloon dilatation AV 20 (41) 8 (42) 6 (29) 6 (67) AV-sparing repair 18 (37) 8 (42) 7 (33) 3 (33) Coarctation of the aorta repair 3 (6) 2 (11) 1 (5) Resection of the subvalvular aortic membrane 2 (4) 2 (22) Mitral valve reconstruction 2 (4) 1 (5) 1 (11) Tricuspidal valve reconstruction 1 (2) 1 (11) Closure of the ventricular septal defect 1 (2) 1 (11) Aortic root replacement (Konno) 1 (2) 1 (11) Reconstruction of the AV with homograft root replacement 1 (2) 1 (11) Reduction in the ascending aorta 1 (2) 1 (5) Closure of the atrial septal defect 1 (2) 1 (11) Total procedures 51 20 14 17 Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Balloon dilatation AV 20 (41) 8 (42) 6 (29) 6 (67) AV-sparing repair 18 (37) 8 (42) 7 (33) 3 (33) Coarctation of the aorta repair 3 (6) 2 (11) 1 (5) Resection of the subvalvular aortic membrane 2 (4) 2 (22) Mitral valve reconstruction 2 (4) 1 (5) 1 (11) Tricuspidal valve reconstruction 1 (2) 1 (11) Closure of the ventricular septal defect 1 (2) 1 (11) Aortic root replacement (Konno) 1 (2) 1 (11) Reconstruction of the AV with homograft root replacement 1 (2) 1 (11) Reduction in the ascending aorta 1 (2) 1 (5) Closure of the atrial septal defect 1 (2) 1 (11) Total procedures 51 20 14 17 AV: aortic valve. Table 2: Previous cardiac procedures Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Balloon dilatation AV 20 (41) 8 (42) 6 (29) 6 (67) AV-sparing repair 18 (37) 8 (42) 7 (33) 3 (33) Coarctation of the aorta repair 3 (6) 2 (11) 1 (5) Resection of the subvalvular aortic membrane 2 (4) 2 (22) Mitral valve reconstruction 2 (4) 1 (5) 1 (11) Tricuspidal valve reconstruction 1 (2) 1 (11) Closure of the ventricular septal defect 1 (2) 1 (11) Aortic root replacement (Konno) 1 (2) 1 (11) Reconstruction of the AV with homograft root replacement 1 (2) 1 (11) Reduction in the ascending aorta 1 (2) 1 (5) Closure of the atrial septal defect 1 (2) 1 (11) Total procedures 51 20 14 17 Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Balloon dilatation AV 20 (41) 8 (42) 6 (29) 6 (67) AV-sparing repair 18 (37) 8 (42) 7 (33) 3 (33) Coarctation of the aorta repair 3 (6) 2 (11) 1 (5) Resection of the subvalvular aortic membrane 2 (4) 2 (22) Mitral valve reconstruction 2 (4) 1 (5) 1 (11) Tricuspidal valve reconstruction 1 (2) 1 (11) Closure of the ventricular septal defect 1 (2) 1 (11) Aortic root replacement (Konno) 1 (2) 1 (11) Reconstruction of the AV with homograft root replacement 1 (2) 1 (11) Reduction in the ascending aorta 1 (2) 1 (5) Closure of the atrial septal defect 1 (2) 1 (11) Total procedures 51 20 14 17 AV: aortic valve. Echocardiographic data Two-dimensional echocardiography and colour-flow Doppler were obtained in all patients before surgery, immediately postoperatively, before hospital discharge and at least annually during the follow-up period. Left ventricular dimensions measured by m-mode and the aortic root dimensions measured on the level of the annulus and the sinotubular junction were reviewed. z-scores were calculated on the basis of expected normal aortic dimensions [7] and expected normal left ventricular dimensions [8] for body surface area. Aortic regurgitation was graded on a scale of 0–4 (none, trivial, mild, moderate and severe). Trivial aortic regurgitation was positioned in the analysis as Grade 0.5. Conduit dysfunction was defined as a transvalvular peak gradient exceeding 35 mmHg or a pulmonary regurgitation 2+ on echocardiography. For patients undergoing a reoperation for the LVOT or right ventricular outflow tract, the final echocardiography before the reoperation was used. Holter monitoring The Holter electrocardiogram, conducted on 45 (92%) patients, was performed within 1 year after the procedure to assess rhythm and conduction abnormalities. Operative procedure Operations were conducted through a median sternotomy with cardiopulmonary bypass at a perfusate temperature of 27.2±1.9°C (range 22–32°C). The Ross procedure was performed utilizing the root replacement technique as previously described [9]. In case of a size mismatch between the pulmonary valve and the aortic annulus, the neoaortic root was tailored with annular reduction plasty (n = 21) or enlargement (n = 9) if indicated. In the reduction plasty group, one or a combination of the following surgical techniques was employed to adjust the mismatch and to strengthen the aortic wall to avoid dilatation: purse-string stitches to strengthen the anterior sinus (n = 8), annulus strengthening of the non-coronary sinus using the remnants of the native aortic root (n = 6) and a reduction aortoplasty for mismatch of the ascending aorta with direct resection of a strip of the anterior wall (n = 17). In 9 (18%) patients with annular hypoplasia and LVOT obstruction, we performed the modified Ross–Konno procedure, including annulus division below the commissure between the left and the right coronary cusps with extensive septal myectomy, without creating a ventricular septum defect. To re-establish continuity between the right ventricle and pulmonary artery bifurcation pulmonary homografts (n = 24, mean diameter 22.2 ± 2.1 mm, range 18–26 mm), a bovine valved allograft (Contegra, n = 22, mean diameter 18.9 ± 3.5, range 12–22 mm), aortic homografts (n = 2, mean diameter 16 ± 1.4 mm, range 15–17 mm) or a Medtronic Freestyle valve (n = 1, diameter 25 mm) were implanted. Concomitant procedures are presented in Table 3. Table 3: Concomitant procedures Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Ligature of the patent ductus arteriosus 2 (4) 2 (22) Fenestration of atrial septal defect 1 (2) 1 (5) Closure of the ventricular septal defect 1 (2) 1 (11) Enlargement of the ascending aorta with a xenopericardial patch 1 (2) 1 (11) Mitral valve repair 3 (6) 1 (5) 1 (5) 1 (11) Enlargement of the pulmonary bifurcation with a xenopericardial patch 1 (2) 1 (11) Closure of the persistent foramen ovale 1 (2) 1 (5) Reduction in the pulmonary root with purse-string suture 1 (2) 1 (5) Enlargement of the proximal Contegra with a patch 1 (2) 1 (5) Xenopericardial patch on pulmonary Freestyle prosthesis 1 (2) 1 (5) Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Ligature of the patent ductus arteriosus 2 (4) 2 (22) Fenestration of atrial septal defect 1 (2) 1 (5) Closure of the ventricular septal defect 1 (2) 1 (11) Enlargement of the ascending aorta with a xenopericardial patch 1 (2) 1 (11) Mitral valve repair 3 (6) 1 (5) 1 (5) 1 (11) Enlargement of the pulmonary bifurcation with a xenopericardial patch 1 (2) 1 (11) Closure of the persistent foramen ovale 1 (2) 1 (5) Reduction in the pulmonary root with purse-string suture 1 (2) 1 (5) Enlargement of the proximal Contegra with a patch 1 (2) 1 (5) Xenopericardial patch on pulmonary Freestyle prosthesis 1 (2) 1 (5) Table 3: Concomitant procedures Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Ligature of the patent ductus arteriosus 2 (4) 2 (22) Fenestration of atrial septal defect 1 (2) 1 (5) Closure of the ventricular septal defect 1 (2) 1 (11) Enlargement of the ascending aorta with a xenopericardial patch 1 (2) 1 (11) Mitral valve repair 3 (6) 1 (5) 1 (5) 1 (11) Enlargement of the pulmonary bifurcation with a xenopericardial patch 1 (2) 1 (11) Closure of the persistent foramen ovale 1 (2) 1 (5) Reduction in the pulmonary root with purse-string suture 1 (2) 1 (5) Enlargement of the proximal Contegra with a patch 1 (2) 1 (5) Xenopericardial patch on pulmonary Freestyle prosthesis 1 (2) 1 (5) Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Ligature of the patent ductus arteriosus 2 (4) 2 (22) Fenestration of atrial septal defect 1 (2) 1 (5) Closure of the ventricular septal defect 1 (2) 1 (11) Enlargement of the ascending aorta with a xenopericardial patch 1 (2) 1 (11) Mitral valve repair 3 (6) 1 (5) 1 (5) 1 (11) Enlargement of the pulmonary bifurcation with a xenopericardial patch 1 (2) 1 (11) Closure of the persistent foramen ovale 1 (2) 1 (5) Reduction in the pulmonary root with purse-string suture 1 (2) 1 (5) Enlargement of the proximal Contegra with a patch 1 (2) 1 (5) Xenopericardial patch on pulmonary Freestyle prosthesis 1 (2) 1 (5) Statistical analysis Data are expressed as mean ± standard deviation and range or as median (interquartile range) for continuous variables and as count and percentage of patients for categorical variables. Statistical analysis was performed using SPSS 2010 (IBM Corp., Version 19.0. Armonk, NY, USA) and Microsoft Excel 2010. Overall survival and probability of freedom from reoperation and reintervention was estimated according to the Kaplan–Meier method. Univariable Cox proportional hazards regression was used to evaluate variables (the age at surgery, year of surgery and size of conduit material) as predictors for the right ventricular outflow tract reintervention. A comparison on conduit material (a homograft versus a Contegra conduit) was conducted using the log-rank test. Data were tested for normal distribution using the Anderson–Darling test. The F-test was used to check for the equality of variances prior to the Student’s t-test. Changes in aortic annulus z-score and left ventricular end-diastolic diameter (LVEDD) z-scores over time within the subgroups were analysed using a paired Student’s t-test. Comparisons among subgroups were performed using the 2-sample equal variances Student’s t-test. Changes of the aortic regurgitation grade within the groups have been analysed using the paired sign test, and the Kruskal–Wallis test was used to compare aortic regurgitation grades between the groups. The Fisher’s exact test was used to find out whether there is a correlation between the development of aortic valve regurgitation and aortic annulus root dilatation. A P-value <0.05 was considered statistically significant. Correction of multiple testing was not performed. Early mortality was defined as death within 30 days after the Ross or the Ross–Konno surgery or before discharge from the hospital. RESULTS Follow-up The mean follow-up for reintervention and reoperation was 4.6 ± 2.7 years (9 days to 9.2 years). The inclusion criteria for echocardiographic follow-up was the existence of an echocardiogram for at least 1 year or more after the procedure. The echocardiographic follow-up for aortic regurgitation, aortic annulus, aortic root and LVEDD measurements were reported in 42 (86%), 35 (71%), 24 (49%) and 38 (78%) patients with a mean follow up of 5.3 ± 2.3 (1.1 to 9.2) years, 5.1 ± 2.4 (1.1 to 9.2) years, 5.6 ± 1.7 (3 to 9.2) years and 5.2 ± 2.3 (1.1 to 9.2) years, respectively. Mortality There was no early death. The overall mortality was 6%. Two patients died for cardiac reasons (4%). The cause of death remained unknown in 1 patient. One patient died 6 months after the modified Ross–Konno procedure with a severe pulmonary hypertension at the age of 10 months. The last echocardiography 2 days before death showed a severe persistent pulmonary hypertension with a reduced right ventricular contractility and severe dilated liver and cava inferior veins; the homograft and autograft showed trivial regurgitation without evidence of stenosis. The second death occurred because of acutely decompensated right heart failure 19 months after the modified Ross–Konno operation, which had been performed at the age of 1 month. The last echocardiography showed an eccentric severe right ventricular hypertrophy and a severe hypertrophic hypoplastic left ventricle with massive endomyocardial fibrosis and pulmonary hypertension, which were already described before the modified Ross–Konno procedure. The third death occurred for an unspecified reason 47 months after the Ross operation (no mismatch group), which was performed at the age of 17 years due to combined aortic valve failure. Overall survival estimated using the Kaplan–Meier analysis was 92 ± 4% at the 4-year follow-up (Fig. 1). Figure 1: View largeDownload slide Kaplan–Meier survival curves. Figure 1: View largeDownload slide Kaplan–Meier survival curves. Complications Intraoperative complications were as follows: rhythm disturbances included junctional tachycardia in 2 patients and recurrent ventricular fibrillation with intraoperative atrioventricular (AV)-Block III requiring 4 rounds of defibrillation and a temporary pacemaker in another patient. One patient needed intraoperative coronary artery bypass due to injury of the right coronary artery. In the early postoperative period (defined by the time from post-procedure to discharge) complications were as follows: 1 patient with pulmonary embolism due to activated protein C (APC) resistance (heterozygous factor V Leiden mutation). One patient had post-pump chorea. Delayed complications included 2 cases of autograft endocarditis. In 1 case, there was a successful response to conservative treatment, and surgical treatment was administered in the other. See Table 4 for details. Table 4: Complications, reinterventions and surgeries Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Intraoperative complications  Myocardial infarction 1 (2) 1 (5)  Rhythm disturbances 3 (6) 1 (5) 2 (22) Early postoperative/before discharge  Pulmonary embolism 1 (2) 1 (5)  Left ventricular dysfunction 2 (4) 1 (5) 1 (5)  Post-pump chorea 1 (2) 1 (11) Late postoperative  Endocarditis 2 (4) 1 (5) 1 (5) Reinterventions/resurgeries of the right ventricular outflow tract  Balloon dilatation 6 (12) 2 (10) 1 (5) 3 (33)  Percutaneous pulmonary valve replacement 3 (6) 2 (10) 1 (11)  Conduit replacement and posterior plastic bifurcation pulmonary arteries 1 (2) 1 (11)  Stent pulmonary root 1 (2) 1 (5) Reintervention/resurgery of the left ventricular outflow tract  Abscess debridement of the aortic valve and aortic valve replacement 1 (2) 1 (5) Others  Mitral valve repair 2 (4) 1 (11)  Mechanical mitral valve replacement 1 (2) 1 (5)  Pacemaker 1 (2) 1 (11)  Coronary artery bypass graft 1 (2) 1 (5) Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Intraoperative complications  Myocardial infarction 1 (2) 1 (5)  Rhythm disturbances 3 (6) 1 (5) 2 (22) Early postoperative/before discharge  Pulmonary embolism 1 (2) 1 (5)  Left ventricular dysfunction 2 (4) 1 (5) 1 (5)  Post-pump chorea 1 (2) 1 (11) Late postoperative  Endocarditis 2 (4) 1 (5) 1 (5) Reinterventions/resurgeries of the right ventricular outflow tract  Balloon dilatation 6 (12) 2 (10) 1 (5) 3 (33)  Percutaneous pulmonary valve replacement 3 (6) 2 (10) 1 (11)  Conduit replacement and posterior plastic bifurcation pulmonary arteries 1 (2) 1 (11)  Stent pulmonary root 1 (2) 1 (5) Reintervention/resurgery of the left ventricular outflow tract  Abscess debridement of the aortic valve and aortic valve replacement 1 (2) 1 (5) Others  Mitral valve repair 2 (4) 1 (11)  Mechanical mitral valve replacement 1 (2) 1 (5)  Pacemaker 1 (2) 1 (11)  Coronary artery bypass graft 1 (2) 1 (5) Table 4: Complications, reinterventions and surgeries Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Intraoperative complications  Myocardial infarction 1 (2) 1 (5)  Rhythm disturbances 3 (6) 1 (5) 2 (22) Early postoperative/before discharge  Pulmonary embolism 1 (2) 1 (5)  Left ventricular dysfunction 2 (4) 1 (5) 1 (5)  Post-pump chorea 1 (2) 1 (11) Late postoperative  Endocarditis 2 (4) 1 (5) 1 (5) Reinterventions/resurgeries of the right ventricular outflow tract  Balloon dilatation 6 (12) 2 (10) 1 (5) 3 (33)  Percutaneous pulmonary valve replacement 3 (6) 2 (10) 1 (11)  Conduit replacement and posterior plastic bifurcation pulmonary arteries 1 (2) 1 (11)  Stent pulmonary root 1 (2) 1 (5) Reintervention/resurgery of the left ventricular outflow tract  Abscess debridement of the aortic valve and aortic valve replacement 1 (2) 1 (5) Others  Mitral valve repair 2 (4) 1 (11)  Mechanical mitral valve replacement 1 (2) 1 (5)  Pacemaker 1 (2) 1 (11)  Coronary artery bypass graft 1 (2) 1 (5) Total, n (%) No mismatch, n (%) Reduction plasty, n (%) Ross–Konno, n (%) Intraoperative complications  Myocardial infarction 1 (2) 1 (5)  Rhythm disturbances 3 (6) 1 (5) 2 (22) Early postoperative/before discharge  Pulmonary embolism 1 (2) 1 (5)  Left ventricular dysfunction 2 (4) 1 (5) 1 (5)  Post-pump chorea 1 (2) 1 (11) Late postoperative  Endocarditis 2 (4) 1 (5) 1 (5) Reinterventions/resurgeries of the right ventricular outflow tract  Balloon dilatation 6 (12) 2 (10) 1 (5) 3 (33)  Percutaneous pulmonary valve replacement 3 (6) 2 (10) 1 (11)  Conduit replacement and posterior plastic bifurcation pulmonary arteries 1 (2) 1 (11)  Stent pulmonary root 1 (2) 1 (5) Reintervention/resurgery of the left ventricular outflow tract  Abscess debridement of the aortic valve and aortic valve replacement 1 (2) 1 (5) Others  Mitral valve repair 2 (4) 1 (11)  Mechanical mitral valve replacement 1 (2) 1 (5)  Pacemaker 1 (2) 1 (11)  Coronary artery bypass graft 1 (2) 1 (5) Reoperation of the left ventricular outflow tract Only 1 autograft reoperation was carried out. The patient had autograft endocarditis with paravalvular abscess 5 weeks after the Ross operation (reduction plasty group) as a result of an infected sacral dermoid, followed by operative paravalvular abscess debridement. Six years after the Ross procedure, the same patient developed progressive dilatation of the aortic valve root (50 mm) with pseudoaneurysm of the posterior aortic valve annulus and severe aortic regurgitation. The ascending aorta showed no dilatation. Correction of the pseudoaneurysm was performed by the U stich suture. Because of the altered anatomy after the aneurysm correction, a valve-sparing root replacement (Tirone David) failed, and AVR (a 29-mm Medtronic Freestyle valve) was inevitable (Table 4). Autograft and left ventricular function and dimensions At the last follow-up, mean z-scores at the annular level were 2.1 ± 1.7 in the no mismatch group, 2.5 ± 1.6 in the reduction plasty group and 3.6 ± 1.6 in the Ross–Konno group. An aortic annulus z-score >2 was found in 58% (no mismatch group), 50% (reduction plasty group) and 83% of patients (Ross–Konno group). A comparison between discharge and follow-up within the subgroups revealed a significant change over time of the aortic annulus z-score in the Ross–Konno group (P = 0.03) but not in the no mismatch or reduction plasty group. A comparison between the subgroups at discharge and the latest follow-up disclosed no significant differences in aortic annulus z-scores. In the overall cohort, the increase in aortic annulus was 0.1 cm/year, analogous to an increase in z-scores by 0.24/year (no mismatch group), 0.21/year (reduction plasty group) and 0.34/year (Ross–Konno group). z-scores over time are shown in Fig. 2. Figure 2: View largeDownload slide Aortic annulus z-score shift over time. The bottom and top edges of the box are 25th percentile and 75th percentile, respectively, and the central mark indicates the median. The end of the whiskers represent minimum and maximum values. Figure 2: View largeDownload slide Aortic annulus z-score shift over time. The bottom and top edges of the box are 25th percentile and 75th percentile, respectively, and the central mark indicates the median. The end of the whiskers represent minimum and maximum values. The mean aortic root diameter at sinotubular junction and z-score were 3.7 ± 0.7 cm (range 2.3–5) and 2.8 ± 1 (0.9–5), corresponding to a z-score of 2.8 ± 1 (1.5–4.8) (no mismatch group), 3 ± 1.2 (0.9–5) (reduction plasty group) and 2.4 ± 0.9 (1.5–4) (Ross–Konno group). A dilatation of the aortic root (defined as a z-score >2) was diagnosed in 9 (82%) patients in the no mismatch group, in 7 patients (88%) in the reduction plasty group and in 4 (80%) patients in the Ross–Konno group. At the latest follow-up, 93% of the patients had none-to-mild aortic valve regurgitation. One patient with severe aortic regurgitation and an aortic root measuring 5 cm required an AVR (see above). Another 2 patients with aortic root diameters of 4.7 cm and concomitant regurgitation are in stable clinical condition. In general, the aortic regurgitation grade grew slowly (0.04 ± 1.6 grades/year) without reaching statistical significance (P = 0.36). Twenty-three (55%) of the patients maintained the same aortic regurgitation grade from discharge to the last follow-up, 12 (29%) improved and 7 (17%) worsened. Comparison within the subgroups during follow-up and between subgroups at discharge and follow-up revealed no significant increase or differences of aortic regurgitation grade. The grade distribution of aortic regurgitation over time is shown in Fig. 3. Figure 3: View largeDownload slide Aortic regurgitation (AR) grade shift over time. Figure 3: View largeDownload slide Aortic regurgitation (AR) grade shift over time. There is no correlation between the development of aortic regurgitation and aortic annulus root dilatation (P = 0.61). Forty-five (92%) patients had no LVOT obstruction, and 2 (4%) patients had trivial autograft stenosis. The echocardiographic outcome of left ventricular dimensions is shown in Fig. 4. After an initial postoperative decline of the LVEDD z-scores, we observed a significant increase within the no mismatch (P = 0.013) and reduction plasty groups (P = 0.023) during follow-up. Nevertheless, measurements and z-scores were within normal range in all groups at the latest follow-up; LVEDD z-scores were 0.2 ± 1.5 (−2.6 to 2.6) (no mismatch group), 0.7 ± 1.1 (−1.3 to 3) (reduction plasty group) and 0.6 ± 1.2 (−1.4 to 2.6) (Ross–Konno group). Figure 4: View largeDownload slide Left ventricular end-diastolic diameter (LVEDD) z-score shift over time. Figure 4: View largeDownload slide Left ventricular end-diastolic diameter (LVEDD) z-score shift over time. Comparison within the Ross–Konno group and between the subgroups at discharge and follow-up showed no significant differences in z-scores. The mean ejection fraction was 61 ± 7% (range 50–78%), without significant differences between the subgroups. Reintervention and reoperation of the right ventricular outflow tract During follow-up 6 (12%), patients underwent right ventricle and pulmonary artery graft reintervention or reoperation within a mean interval time of 2.6 ± 1.9 (range 0.7–5.4) years (Table 4). Right ventricle and pulmonary artery conduit stenosis was the leading cause of all. Univariate risk factors for reinterventions were: the use of a Contegra conduit (P = 0.027), younger age (P = 0.019) and smaller conduit size (P = 0.023). Overall freedom from the right ventricular outflow tract reintervention and reoperation was 90 ± 5% at 2.5 years. Holter monitor One patient (Ross–Konno group) showed a postoperative left bundle branch block with severe mitral valve regurgitation and needed a pacemaker implantation 8 months after the procedure. DISCUSSION It is common knowledge that the Ross procedure is a reproducible and durable procedure. There is further ongoing critical analysis of specific techniques and their relationship to specific event rates from the German–Dutch Ross Registry, which now includes 1779 adult patients from 8 participating centres, spanning 24 years [10], and from the Italian Paediatric Ross Registry, including 305 children, spanning 23 years [5]. To our knowledge, this study is focusing for the first time on additional surgical modifications to the root technique at the annular level in children—such as the modified Konno incision or reduction plasty to correct autograft–aortic mismatch—and their effect on the structural and functional quality of the autograft at a clinical follow-up of 5 years. Based on published data, overall survival for the standard Ross procedure is described as 93.9% at 5 years [11] and 96%, 90.4% and 95% at 10 years [11–13]. Our data confirm these findings, with freedom from mortality of 91.9% at 4-year follow-up. Two of the 3 deaths occurred in the Ross–Konno group. These 2 patients were aged 1 month and 10 month at the time of the operation with a higher mortality risk according to Brown et al. [14], who showed that age less than 1 year was the most sensitive predictor of mortality of patients undergoing the Ross–Konno procedure. Nelson et al. [15] not only observed higher mortality rates for infants after the Ross Procedures but also showed excellent long-term autograft durability in the same group. In general, controversies linger mainly because the Ross procedure puts 2 valves at risk. This might increase the number of reoperations and interventions owing to degeneration of the homograft or autograft failure [11, 16]. Whether the postoperative increase in the aortic annulus root size is due to somatic growth or pathological remodelling with disproportionate dilatation is still under discussion [17]. Excessive dilatation and autograft failure would lead to aortic valve regurgitation [18, 19]. In this cohort, the need for reintervention on the autograft was limited. During a mean follow-up of 4.6 years, only 1 patient required reoperation on the autograft. In previously published articles, freedom from autograft reinterventions is described as 97% at 5 years [20], 74%, 80% and 86% at 10 years [5, 12, 20] and 75% at 15 years [5]. Hörer et al. [11] published more favourable results in their study containing 152 paediatric patients from the German Ross Registry, with freedom from reoperation of the autograft of 99% at 5 years and 95.5% at 10 years. Prior endocarditis, prior aortic regurgitation and a longer follow-up period emerged as risk factors [11]. As related to autograft structure, in the majority of cases, the neoaortic valve at the annular level grew in a manner that reflected normal somatic proportions in the no mismatch and reduction plasty groups but not in the Ross–Konno group. Although the increase in the entire cohort was 0.1 cm/year, the z-score of the aortic annulus in the modified Ross–Konno group was already larger before discharge: therefore, a further increase led to noticeable growth beyond the usual limits. Nevertheless, diameters and z-scores of the sinotubular junction were smaller in the modified Ross–Konno group. Additionally, normalization of left ventricular dimensions after the procedure, as indicated in previous studies [12, 13, 17, 21], along with the ejection fraction obtained are proof that the left ventricular function was preserved. In contrast to Frigiola et al. [12], we found a sizable but slow increase in LVEDD over time. Nevertheless, all measurements fell within the normal range at the final follow-up. The mean aortic root diameter was 37 ± 7 mm (range 23–50 mm), yielding a z-score of 2.8 ± 1 (0.9–5) at the latest follow-up. Analogous results are stated in the literature with mean aortic root diameters varying between 35 and 37 mm [13, 21–23]. The comparability of the echocardiographic findings, according to diameters and z-scores, concerning the occurrence of dilatation is limited because the definition of dilatation differs. Based on the definition that a z-score >2 equates to more than the 95th percentile, we found 83% of patients meeting this criterion and confirming a dilatation of the aortic root in previous observations with 52% [24], 64% [13], 75% [25] and 90% [22]. Another method for specifying autograft function, which additionally considers different follow-up times, was used by Pasquali et al. [17], Hörer et al. [19] and Frigiola et al. [12]. They analysed the change in aortic root dimensions in cm per year and found a significant increase in the size of the aortic root at the level of the sinus of Valsalva (0.1–0.5 cm/year) and the sinotubular junction (0.08–0.7 cm/year). Frigiola et al. [12] and Pasquali et al. [17] described no direct association between neoaortic root dilatation and neoaortic regurgitation, whereas Hörer et al. [19] showed significant evidence that aortic regurgitation increases the sinotubular junction diameter (P = 0.028). Despite aortic root dilation (defined as a z-score >2), in 83% of our study population, the development of higher grade aortic valve regurgitation was exceptional, with only 3 of 45 (7%) patients showing more than mild autograft regurgitation. Analogous findings are outlined by Clark et al. [21] and El Behery et al. [13]. Our results are in line with Frigiola et al. [12] and Pasquali et al. [17], revealing no significant correlation of neoaortic root dilatation and progress of autograft regurgitation (P = 0.61). Risk factors for the development of aortic regurgitation described by others are the degree of aortic regurgitation at discharge [12], prior AVR (P = 0.002) and prior ventricular septal defect repair (P = 0.02) [17]. Hörer et al. [19] found a gradual but significant increase in the grade of aortic regurgitation with follow-up time (0.06 ± 0.02 grades per year, P < 0.001) [20]. We can confirm an even lower increase in regurgitation grade (0.04 ± 0.16 grades/year) without reaching statistical significance (P = 0.36). The impact of this finding remains unknown since none of these patients had a grade of more than mild aortic regurgitation at the final follow-up. Therefore, a longer follow-up is needed. Limitations The limitations of the study are the small cohort and the retrospective design. CONCLUSION In our patient cohort, overall mortality, reoperation and reintervention rates were low. The autograft function showed guaranteed results at the mid-term follow-up. Despite the fact that we observed a larger size of aortic annulus diameter over time when compared with healthy children, the occurrence of aortic regurgitation and the need for reintervention were very low. The incidence of neoaortic valve dysfunction and the need for reintervention may increase over time, especially in the Ross–Konno group; therefore, additional observation is required. In conclusion, surgical modifications (e.g. modified Konno procedure to enlarge LVOT and reduction plasty) at the annular level during a Ross procedure do not negatively influence the structure and function of the autograft at the mid-term follow-up. Conflict of interest: none declared. REFERENCES 1 Ross DN. Replacement of aortic and mitral valves with a pulmonary autograft . Lancet 1967 ; 290 : 956 – 8 . 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Pediatr Cardiol 2008 ; 29 : 894 – 900 . Google Scholar CrossRef Search ADS PubMed 25 Kalavrouziotis G , Raja S , Ciotti G , Karunaratne A , Corno AF , Pozzi M. Medium-term results from pulmonary autografts after the Ross procedure in children and adolescents . Hellenic J Cardiol 2006 ; 47 : 337 – 43 . Google Scholar PubMed © The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices)

Journal

Interactive CardioVascular and Thoracic SurgeryOxford University Press

Published: May 15, 2018

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