Repair of Left Ventricular Inflow Tract Lesions in Shone s Anomaly: Valve Growth and Long-Term Outcome

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1 Repair of Left Ventricular Inflow Tract Lesions in Shone s Anomaly: Valve Growth and Long-Term Outcome Eva Maria B. Delmo Walter, MD, PhD, Richard Van Praagh, MD, Oliver Miera, MD, and Roland Hetzer, MD, PhD Departments of Cardiothoracic and Vascular Surgery, and Pediatric Cardiology and Congenital Heart Diseases, Deutsches Herzzentrum Berlin, Berlin, Germany; and Department of Pediatric Cardiology, Children s Hospital Boston, Boston, Massachusetts Background. The degree of involvement of left ventricular inflow tract obstruction is the predominant factor determining outcome in Shone s anomaly. In this series of patients with Shone s anomaly, we evaluated the impact of mitral valve (MV) repair strategies performed to correct the components of this anomaly on growth of the valve and long-term functional outcome in children. Methods. In the last 25 years, 45 children, mean age years (median, 3.9; range, 2 months 16.8 years), underwent surgical correction of Shone s anomaly. Coarctation of the aorta was found in 40%, subaortic stenosis due to fibromuscular hypertrophy was found in 55%, and subvalvar membrane was found in 66% of these patients. Left ventricular inflow tract obstruction was brought about by fused commissures with dysplastic and shortened chordae in 53.3%, valve hypoplasia in 11.1%, supravalvar mitral ring in 100%, and parachute valve in 17.8 of patients%. Results. Various repair strategies were performed according to the presenting morphologic characteristics in patients with either previously corrected or concomitant correction of the left-sided obstructive lesions. Mean duration of follow-up was years. Freedom from reoperation was 52.8% 11.8%, wherein 23 patients underwent repeated MV repair and 1 patient underwent MV replacement after failed attempts at repair. The cumulative survival rate was 70.3% 8.9% at 15 years. Severity and type of mitral abnormalities, left ventricular outflow tract lesions, and pulmonary hypertension are risk factors for reoperation and mortality (p < 0.05). Conclusions. Repair allowed growth of the MV. Longterm outcome of MV repair in Shone s anomaly is related to the degree that the obstructive lesions can be relieved. (Ann Thorac Surg 2013;95:948 55) 2013 by The Society of Thoracic Surgeons The finding in Shone s original description [1] that the extent of mitral valve (MV) involvement seems to be the predominant factor determining outcome has been supported by Bolling and colleagues [2] in their review of 30 cases. This was also the finding of Brauner and associates [3] in their study of 19 cases, of Brown and coworkers [4] in their reported 27 cases, and of Ikemba and colleagues [5], who published MV morphologic features and morbidity/mortality rates in 50 patients with Shone s complex. Serraf and colleagues [6] categorized 25 patients having Shone s syndrome among their reported series of 72 infants having congenital mitral stenosis (MS), and others have reported sporadic cases describing the anomaly [7 9]. To date, only a total of 134 patients operated on, with long-term outcomes, have been specifically reported in the literature. In this study, we analyzed the operative results and long-term outcomes of MV repair performed to correct Accepted for publication Sept 7, Presented at the Poster Session of the Forty-eighth Annual Meeting of The Society of Thoracic Surgeons, Fort Lauderdale, FL, Jan 28 Feb 1, Address correspondence to Dr Delmo Walter, Deutsches Herzzentrum Berlin, Augustenburger Platz 1, 13353, Berlin, Germany; delmowalter@dhzb.de. the multiple left ventricular inflow tract lesions in Shone s anomaly, as well as the impact of these repair strategies on MV growth. Patients and Methods The Institutional Review Board at Deutsches Herzzentrum Berlin approved this study and waived the need for patient consent. Patients Medical records including preoperative evaluations, operative notes, and follow-up data from 958 children and young adolescents diagnosed with left ventricular inflow (MV lesions) and outflow tract (subaortic stenosis, hypertrophic obstructive cardiomyopathy, coarctation of the aorta) obstructive lesions, who underwent surgical procedures between June 1986 and March 2011 at the Deutsches Herzzentrum Berlin, Germany were reviewed retrospectively. Forty-five infants and children (mean age, years; median, 3.9 years; range, 2 months 16.8 years) were filtered out who had the 4 components of Shone s anomaly (any type of MS that included mitral ring, parachute valve, and coarctation of the aorta and/or 2013 by The Society of Thoracic Surgeons /$36.00 Published by Elsevier Inc

2 Ann Thorac Surg DELMO WALTER ET AL 2013;95: SHONE S ANOMALY AND LEFT VENTRICULAR INFLOW TRACT 949 Table 1. Morphologic Features in 45 Patients with Shone s Anomaly Lesions n (%) Left ventricular inflow tract (mitral valve) Typical congenital MS (type I) 32 (71.1) MV dysplasia (type II MS) 5 (11.1) Supravalvular mitral ring (type III MS) 45 (100) Parachute valve (type IV MS) 8 (17.7) Left ventricular outflow tract Subaortic stenosis 45 (100) Fibromuscular hypertrophy 32 (71.1) Subvalvar membrane 23 (51.6) Coarctation of aorta 40 (88.8) Hypoplastic aortic arch 5 (11.1) Associated anomalies Patent ductus arteriosus 28 (62.2) Atrial septal defect 15 (33.3) Ventricular septal defect 11 (24.4) Vascular ring 3 (6.7) MS mitral stenosis; MV mitral valve. hypoplastic arch) (Table 1) severe enough to have required intervention regardless of whether a single-stage or staged operation was performed. The remaining patients reviewed who lacked any 1 of these components as well as those with left-sided obstructive lesions (ie, hypoplastic or small left ventricle managed with biventricular repair) were excluded from this study. The follow-up medical and echocardiographic records of the included patients were provided by the Department of Congenital Heart Disease/Pediatric Cardiology and Department of Clinical Studies, Deutsches Herzzentrum Berlin and by written correspondence from the referring physicians. No patients were lost to follow-up. These children were divided into age groups as follows: 0 to less than 1 year (n 12; mean age, months; median, 0.32 months; range, months), 1 to 5 years (n 19; mean age, years; median, 3.6 years; range, years), older than 5 to 10 years (n 8 years; mean age, years; median, 8.6 years; range, years), and older than 10 years (n 6; mean age, years; median, 15.2 years; range, years). All patients were in modified Ross functional class III-IV (n 31)/NYHA class III (n 14). Anatomic Evaluation of Mitral Valves All these 45 children and adolescents received a complete 2-dimensional echocardiographic examination before operation, at the time of discharge from hospital, and in a series of follow-up visits. All had abnormal MVs with supravalvar mitral ring and at least 2 other left-sided obstructive lesions severe enough to require interventions. MV anomalies were defined according to Ruckman and Van Praagh s [10] classification of MS. Type I typical congenital MS was seen in 24 patients. Type II hypoplastic MV was seen in 5 patients. This form of MS was associated with severe left ventricular outflow tract abnormalities in all cases. Type III supravalvar mitral ring was seen in 45 patients. It was variable in thickness and extent and ranged from a thin membrane to a thick discrete fibrous ridge. The membrane was often adherent to the anterior MV leaflet. This was associated with variable abnormalities of the MV subvalvar apparatus. Type IV parachute valve was seen in 8 patients and was described as having the usual 2 MV leaflets and commissures but all chordae tendineae; instead of inserting into 2 papillary muscles it merged into 1 major papillary muscle. The valve naturally was deformed and the chordae were short and thick; this, coupled with their convergent papillary insertion, allowed restricted leaflet mobility, thus creating a stenotic MV because the leaflets were closely apposed, greatly reducing the effective mitral orifice area. Coarctation of the aorta was the most prevalent left-sided obstructive lesion, seen in 40 (89%) patients. Hypoplastic aortic arch was seen in 8 (18%) patients, diffuse subaortic stenosis caused by fibromuscular hypertrophy in 32 (71%) patients, and discrete membrane in 23 (51%) patients. Associated cardiac anomalies included ventricular septal defect (n 11 [24%]), atrial septal defect (n 15 [33%]), patent ductus arteriosus (n 28 [62%]), and vascular ring (n 3 [7 %]). Hemodynamic Evaluation A gradient greater than or equal to 5 mm Hg across the MV was considered significant and was observed in all 45 (100%) children: mean mm Hg (median 25.6; range 8 30 mm Hg). Mean systolic pressure gradient at the area of subaortic obstruction was mm Hg (median, 57.8; range, mm Hg) and mean coarctation gradient was mm Hg (median, 63.2; range, mm Hg). Eleven patients presented with symptoms of congestive heart failure. Three patients with associated ventricular septal defect had significant pulmonary hypertension (median pulmonary artery pressures of 32 and 47 mm Hg, at rest and during exertion, respectively, with a pulmonary-to-systemic flow ratio 1.5). Echocardiographic Evaluation of Mitral Stenosis Mitral stenosis was quantified by measurement of the MV orifice area (cm 2 ) and mean resting end-diastolic gradient (mm Hg) and was graded 0 (4 6 cm 2 ; 0 mm Hg), I/mild (2 4 cm 2 ; 5 mm Hg), II/moderate (1 2 cm 2 ; 5 10 mm Hg), III/severe ( 1cm 2 ; 10 mm Hg). Preoperatively, 34 (75.6%) patients had moderate MS (grade II), whereas 11 (24.4%) patients had severe (grade III) MS. Surgical Technique All 45 patients underwent a total of 367 procedures to repair the left ventricular inflow and outflow tract obstructive lesions, including the repair of associated anomalies. For the left ventricular inflow tract obstructive lesions, a total of 141 procedures were performed (Table 2). Indications for MV repair were abnormal MV with less than 2 cm 2 orifice area and mean resting end-diastolic gradient of greater than 5 mm Hg, presence of supramitral ring, and associated left ventricular out-

3 950 DELMO WALTER ET AL Ann Thorac Surg SHONE S ANOMALY AND LEFT VENTRICULAR INFLOW TRACT 2013;95: Table 2. Surgical Procedures Performed on Left Ventricular Inflow Tract in 45 Patients Number of Procedures Surgical Procedures Primary MV Repair Repeated MV Repair Third Intervention Total Resection of supravalvular mitral ring Repair of parachute valve a 10 Commissurotomy Papillary muscle division Chordal division a MV replacement. MV mitral valve. flow obstructive lesions. Hemodynamic criteria included pulmonary artery pressure greater than 25 mm Hg at rest and greater than 30 mm Hg on exertion. Increased left atrial to left ventricular pressure gradient was an indication for repeated MV operations. Single-stage repair was performed in 23 patients because all obstructive lesions and intracardiac defects that were deemed significant were diagnosed all at once. This, however, did not preclude eventual reinterventions when necessary. Staged repair was performed in 22 patients. The usual first operations addressed the left ventricular outflow tract, and the next interventions were performed as the other concomitant lesions appeared hemodynamically significant to warrant surgical intervention. In general, we first treat the most distal obstructive lesion, which is usually the coarctation. All 45 children in whom MV operations were performed at any stage in the disease had a significant transmitral gradient justifying the necessity for intervention. All patients had biventricular repair. No patient had a hypoplastic, small, or even borderline left ventricle. MV repair was performed through a median sternotomy using cardiopulmonary bypass with moderate systemic hypothermia. Antegrade intermittent cold crystalloid cardioplegia was used for myocardial protection. Through a left atriotomy along the interatrial groove, the mitral annulus, leaflets, chordae tendineae, and papillary muscles were exposed and meticulously inspected to determine the precise nature of the lesion. Leaflet coaptation was assessed with a forceful transvalvular injection of saline with a bulb syringe. Using a nerve hook, the coaptation of the anterior and posterior leaflets with regard to the presence of sufficient tissue along the coaptation plane was assessed. The valve orifice area was assessed with a Ziemer-Hetzer valve sizer (Fehling Instruments GmbH, Karlstein, Germany). The nomogram published by Rowlatt and colleagues [11] is helpful in determining the normal valve diameter for a specific body surface area. Various repair techniques were used in accordance with the cause of MS and the presenting valve morphologic features. In children with fused commissures, commissurotomy was performed on both the anterolateral and posteromedial commissures [12]. Division of the chordae tendineae and division and splitting of papillary muscles were performed in patients with short, fused, and matted chordae [12]. Parachute valve has the usual 2 MV leaflets and commissures, but all the chordae tendineae are merged into 1 major papillary muscle. It often presents as a funneltype structure with some distinct fibrous lines at the sites of commissural fusion. The most appropriate site for leaflet-splitting incisions was defined on both sides from the common papillary muscles toward the assumed trigones (commissurotomy and fenestration). These incisions were extended into the body of the papillary muscle, which was split toward its base, ensuring sufficient thickness of both new papillary muscle heads [13]. The degree and extent of incision, commissurotomy, and fenestration were measured using the previously mentioned Ziemer-Hetzer valve sizer as determined by the minimal age-related acceptable MV diameter [11]. Sharp dissection of the supravalvar ring was required to initiate the resection. It is very important to remove all components of the ring. Since the ring is usually within the mobile portion of the leaflet, precautions were taken to avoid injuring the leaflet body when dissecting the ring off. In all the repair strategies used, we ensured that the minimal final MV opening area should not be smaller than 10% less than the norm according to body surface area in children. No mitral insufficiency ensued in 37 (82%) patients from the techniques used, whereas 8 (18%) patients had trivial or mild insufficiency. Regardless of the underlying pathologic condition and techniques used, no patient was discharged from the hospital with more than mild stenosis/insufficiency. Postoperative transthoracic echocardiography was carried out annually or if clinically indicated on the basis of symptoms. Statistical Analysis All data were analyzed with the SPSS statistical program for Windows, version 16.0 (IBM Corp, Armonk, NY) software program. Data are expressed as absolute and percentage frequency values and continuous data as mean standard deviation, median, and range, as appropriate. Repeated measurements of echocardiographic variables (MV area [cm 2 ], annulus size [cm], and anterior leaflet area [cm]) in serial timelines and in relation to somatic growth were analyzed with Friedman tests. Z- scores were calculated and the numbers of values greater than 2 were counted. To facilitate comparison between preoperative and follow-up MV dimensions, z values were computed as follows: z score 0 (measured value

4 Ann Thorac Surg DELMO WALTER ET AL 2013;95: SHONE S ANOMALY AND LEFT VENTRICULAR INFLOW TRACT 951 mean value of normal controls)/standard deviation of normal controls. To adjust for age-, body size, and growth-related changes in MV dimensions, linear measurements were indexed to the square root of body surface area (BSA) 0.5 [14]. Normal growth was defined as a lack of z score change between early and late follow-up. Failure of growth of any dimension would be detected as a statistically significant decline in z score. Freedom from reoperation and cumulative survival rates were analyzed according to Kaplan-Meier estimates with 95% confidence interval (CI) and Cox proportional hazard regression methods to identify the risk factors for reoperation and mortality. A p value of less than 0.05 was considered significant. Results Morbidity Four patients, the ones who also underwent concomitant closure of ventricular septal defects, required permanent pacemaker implantation for complete heart block performed within 30 days after the operation. Early Mortality A 3-month-old infant who underwent urgent singlestage surgical intervention for all the obstructive lesions of Shone s anomaly with associated pulmonary hypertension (mean pulmonary artery pressure of 32 mm Hg), ventricular septal defect, and patent ductus arteriosus had mild residual MS (MV orifice area of 2 cm 2 and mean resting end-diastolic gradient 5 mm Hg) and a left atrial pressure of 12 mm Hg postoperatively. Low-output cardiac failure, hemodynamic instability, and hypotension ensued 34 hours after the procedure and he was placed on an extracorporeal membrane oxygenator. Capillary leak syndrome eventually developed and he died on the 18th postoperative day. Late Mortality Eight late deaths occurred among the 44 patients who were discharged from the hospital. A 2-month-old infant with the typical congenital MS who underwent repeated MV repair with concomitant repair of the coarctation of the aorta and repeated septal myectomy 4 months later died of heart failure a year later. A patient with parachute valve who was 2 years old at the time of the initial MV repair underwent repeated repair 5 years postoperatively. He underwent MV replacement 2 years later but died 8 years postoperatively. Six patients died of a noncardiac event at 1 (seizures), 3 (end-stage renal failure), 5 (n 2 [end-stage renal failure and pneumonia]), 8 (vehicular accident), and 13 (unknown) years postoperatively. The cumulative survival rates were 97.6% 2.4%, 92.3% 4.3%, 83.8% 6.1%, 75.7% 7.8% and 70.3% 8.9%, at 30 days, 1 year, 5 years, 10 years, and 15 years postoperatively, respectively (Fig 1A). Overall survival rates by age group during a mean duration of follow-up of years (range, years) are shown in Fig 1B. Operative Outcome of Mitral Valve Repair FUNCTIONAL CLASS. There was a significant improvement in functional class postoperatively (p 0.001), and this was sustained until the late follow-up period (Fig 1C). SEVERITY OF MS. Absence of MS (mean MV orifice area cm 2 without mean resting end-diastolic pressure gradient) was noted after the MV repair (p 0.001). Over the follow-up period, 14 patients progressively experienced significant MS (mean MV orifice area cm 2 and mean resting end-diastolic pressure gradient mm Hg) warranting repeated intervention (Fig 1D). Outcome of Resection of Supravalvular Mitral Ring Twelve (27%) patients who underwent primary resection for supravalvular mitral ring had to undergo repeated resection. Ten patients had type I congenital MS with fused commissures and thickened leaflets and 2 patients had hypoplastic MV (type II): 1 of these patients had shortened chordae and the other had miniature papillary muscles. These were also the patients with the membranous variety, which may not have been detected during the initial resection because the membrane was adherent to the anterior MV leaflet and some tissue components also remained proximal to the posterior mitral leaflet. Along with the resection of the membranous ring, these patients also underwent commissurotomy, chordal division, and papillary muscle splitting. However, their latest echocardiographic evaluations showed absence of MS. Follow-Up FREEDOM FROM REOPERATION AFTER MV REPAIR. Mean duration of follow-up was years (range, years). Freedom from reoperation was 97.6% 2.4%, 89.3% 5.1%, 77.1% 7.2%, 72.0% 8.3%, and 52.8% 11.8%, at 30 days, 1 year, 5 years, 10 years, and 15 years postoperatively, respectively. Stratified based on age groups at the time of initial repair, freedom from reoperation was 100% at 30 days in all age groups. In the less than 1 year old group, freedom from reoperation was 95.56% at 1 year and was sustained until the late follow-up period. Repeated MV repair was performed mostly in the 1- to 5-year age group until the 10-year follow-up. It was noteworthy that there were no repeated MV operations 5 years after the initial MV repair in the 10 year old or older group. Only 1 MV replacement was performed, and this was in a patient with parachute valve (see section on late mortality). Thirty-two repeated MV procedures were performed in 14 patients and were all related to restenosis and repeated MV dysfunction. These were performed mostly for type I MS and hypoplastic MV. Table 3 shows the multivariate analysis of perioperative risk factors for reoperation and mortality. In this series, the types of MS type I congenital MS with fused commissures and thickened leaflet (p 0.004), type II hypoplastic MV (p 0.001), supravalvular mitral ring (p 0.002), and parachute valve (p 0.003) as well as associated pulmonary hypertension (p 0.001) and left ventricular outflow tract lesions (p 0.00) are significant risk factors. The repair techniques as well as staged surgical intervention, however, proved not to be influential in the outcome in this study population.

5 952 DELMO WALTER ET AL Ann Thorac Surg SHONE S ANOMALY AND LEFT VENTRICULAR INFLOW TRACT 2013;95: Fig 1. (A) Cumulative survival. (B) Overall survival. (C) Freedom from reoperation stratified by age group. (D) Overall survival stratified by age group. MV GROWTH. The increase in MV area (Fig 2A), which is substantial from mm to mm (z score, 1.9 to 1.8; p 0.000), implied MV growth over a mean period of years at a 96% CI. The anterior mitral leaflet area, measured to be mm compared with a preoperative area of (z score 1.7 to 2.0; p 0.000), has also grown.

6 Ann Thorac Surg DELMO WALTER ET AL 2013;95: SHONE S ANOMALY AND LEFT VENTRICULAR INFLOW TRACT 953 Table 3. Multivariate Analysis of Perioperative Risk Factors for Reoperation and Mortality Variable Odds Ratio 95% CI p Value Preoperative Urgency Age Left ventricular inflow tract obstructive lesions Type I MS (thickened leaflets and commissural fusion) Type II MS (hypoplastic mitral valve) Type III MS (supravalvar mitral ring) Type IV (parachute valve) Associated left ventricular outflow tract obstructive lesions Pulmonary hypertension Surgical approach Single-stage operation Staged repair CI confidence interval; MS mitral stenosis. Planimetric measurements of the annular area revealed a mild but significant increase in the size of the annulus. Over the mean follow-up period of years, the mean annular size increased to mm from mm (z score 1.9 to 2.1; p 0.000) (Fig 2B). When indexed to body surface area (z score range, 2.0 to 2.0), all calculated z scores at 1 year and 10 years after MV repair were normal As body surface area increased, there was an associated rise in MV dimensions. The mean atrial diameters and mass, which were 75.6% 18.1% of predicted normal for body surface area after the first year and 94.6% 5.5% of predicted normal after 10 years, suggests that MV growth was appropriate for linear growth. Comment The surgical challenge presented by this series of patients with Shone s anomaly is intensified by the coexistence of restrictive and surgically unfavorable MV morphologic characteristics with other obstructive lesions at an early age. The optimal surgical approach to patients with Shone s anomaly is governed by the morphologic characteristics of each obstructive lesion. We favored an aggressive approach to MV pathologic conditions, ie, we performed MV repair in all patients with a transmitral gradient greater than 5 mm Hg, which in this population was highly emphasized. MV involvement seen in this series does not entirely encompass the features of Shone s anomaly as Shone [1] originally described. Although supravalvular mitral ring Fig 2. (A) Growth of mitral valve over time stratified by age group. (B) Mitral valve area and size of the annulus.

7 954 DELMO WALTER ET AL Ann Thorac Surg SHONE S ANOMALY AND LEFT VENTRICULAR INFLOW TRACT 2013;95: was truly present in all 45 patients, parachute valves composed only 17.7% of the MV lesions. The MV morphologic characteristics in these patients with Shone s anomaly conform to the spectrum of congenital MV anomalies reported by the pathologic studies of Ruckman and Van Praagh [10] and those of others [14, 15] as well as by Shone [1] himself. In our series of parachute deformity, there was considerable variability in the position of the papillary muscles. The papillary muscle was mostly centrally located. We did not see both papillary muscles with attachment of chordae tendineae to only 1 of them, as reported by Brown and colleagues [4]. In this instance, this malformation was called parachute-like asymmetrical MV by Oosthoek and colleagues [14] when they observed that among their 129 autopsy specimens, only 1 had a true parachute MV and 29 had parachute-like valves. The other MV lesions composing the left ventricular inflow tract obstruction were the typical congenital MS (type I) seen in 53% of patients and hypoplastic MV (type II), seen in 11% of patients in this series. We found this form of MS to be associated with severe left ventricular outflow tract abnormalities in all cases. The use of modified surgical repair techniques tailored individually according to the presenting MV morphologic features and the routine use of intraoperative echocardiography have facilitated our confident performance of repair. We agreed with several reports [3, 4, 6, 12, 16 18], including some of ours [13, 19, 20] that long-term results of valve repair are superior to those of replacement in patients with congenital MV anomalies. Since the MV lesions are not isolated, there has not been any concern about the inadequate loading of the left ventricle, which could create an impedance to left ventricular ejection, decreasing cardiac output and an inability to sustain postoperative hemodynamics. The creation of a widely patent and competent left ventricular inflow led to normalization of postoperative pulmonary pressures and adequate ventricular workload. The results of approach to repair in this group have been very encouraging. We believe that this group of patients gains maximally from repair. The single-stage operative approach did not prove to have a significant positive influence on long-term outcome in these patients, even in terms of reoperation, since relief of MS unmasked any existing left ventricular inflow tract lesions. Similar to the report of Serraf and colleagues [6], we found no difference in reoperation rate between those who underwent a single-staged approach and those who had a multistaged approach. To repair the MVs in Shone s anomaly in infants and children is extremely challenging, primarily because of their small size and their immature and enormously fragile leaflet tissues. We were not able to compare the different types of MV repair to assess whether 1 is better than the other because these techniques were modified accordingly with time; hence they could not be recognized as independent risk factors. Our results have shown that the type of MS mostly determine the risk factors that affect outcome (Table 3). Recurrence of supravalvular mitral ring, although rare, has been described [6, 13, 21, 22]. Our experience in 12 patients who underwent repeated resection of supravalvular mitral rings may not be absolutely labeled as recurrences because during the repeated resection, we found that the rings were mostly of a membranous type and completely adherent to the MV leaflet, which may have been difficult to resect during the first intervention because of the absence of a clear line of distinction from the leaflet to which the ring was attached so that safe dissection was doubtful. Having been overly cautious not to damage the leaflet, we could have possibly missed this membranous part of the ring. Parachute valves associated with significant subaortic stenosis were amenable to repair because the main obstructive mitral element was subvalvar. Outcomes in this subgroup are related to the degree to which MS can be relieved. Repair of the typical congenital MS was simple and straightforward. There was no need to touch the thickened and rolled leaflets and we left them as they were. However, it was a predicament to be presented with a diminutive leaflet and subvalvar apparatus in addition to the immensely delicate and underdeveloped, if not insufficient, tissues, particularly in infants with hypoplastic MV. Repair is the only available option. Careful division of the chordae tendineae to provide adequate interchordal spaces and scrupulous splitting of the papillary muscles to provide a fairly adequate functional size and length could provide a functional MV, albeit not a long-lasting one. However, even when the primary repair result is not optimal, time is gained for repeated repair until a definitive adult-sized prosthesis can be implanted. In this series, repeated MV repair was mostly performed in the 1- to 5-year age group because of residual mitral dysfunction that could have been greatly intensified when the other left ventricular outflow tract obstructive lesions became conspicuous after the initial relief of MS. In all these MV lesions in Shone s anomaly, successful repair allowed for valve growth [23] relative to body growth [24]. There was no need for anticoagulation, and preservation of the native MV may make eventual repeated repair or even replacement unnecessary. It is important to note that all patients were in modified Ross/NYHA functional class I with normal growth and development. In conclusion, we have demonstrated that a functional repair approach to left ventricular outflow tract obstruction not only allowed growth of the MV over time that was proportionate to the somatic growth but also led to long-term event-free survival in most of these children. Despite high surgical risk, late outcome in the majority of patients was favorable. We thank Anne Gale, medical editor, for assistance with this article. We also appreciate the assistance of Astrid Benhennour, Christine Detschades, Daniela Moeske-Scholz, Julia Stein, Carla Weber, Helge Haselbach, and Mariano Francisco del Maria Javier. References 1. Shone JD, Sellers RD, Anderson RC, Aadms P, Lillihei CW, Edwards JE. The developmental complex of para-

8 Ann Thorac Surg DELMO WALTER ET AL 2013;95: SHONE S ANOMALY AND LEFT VENTRICULAR INFLOW TRACT 955 chute mitral valve, supravalvular ring of left atrium, subaortic stenosis, and coarctation of aorta. Am J Cardiol 1963;11: Bolling SF, Iannettoni MD, Dick M II, Rosenthal A, Bove EL. Shone s anomaly: operative results and late outcome. Ann Thorac Surg 1990;49: Brauner R, Laks H, Drinkwater DC Jr, Scholl F, McCaffery S. Multiple left heart obstruction (Shones s anomaly with mital valve involvement: long-term surgical outcome. Ann Thorac Surg 1997;64: Brown J, Ruzmetov M, Vijay P, et al. Operative results and outcomes in children with Shone s anomaly. Ann Thorac Surg 2005;79: Ikemba C, Eidem BW, Fraley JK, et al. Mitral valve morphology and morbidity/mortality in Shone s complex. Am J Cardiol 2005;95: Serraf A, Zoghbi J, Belli E, et al. Congenital mitral stenosis with or without associated defects: an evolving surgical strategy. Circulation 2000;102(19 suppl 3):III Prunier F, Furber AP, Laporte J, Geslin P. Discovery of a parachute mitral valve complex (Shone s anomaly) in an adult. Echocardiography 2011;18: Joffe D, Gurvitz M, Oxorn D. An unusual presentation in a patient with Shone s anomaly. Anesth Analg 2008;107: Moustafa SE, Lesperance J, Rouleau JL, Gosselin G. A forme fruste of Shone s anomaly in a 65 year-old patient. Mcgill J Med 2008;11: Ruckman R, Van Praagh R. Anatomic types of congenital mitral stenosis: report of 49 autopsy cases with consideration of diagnosis and surgical implications. Am J Cardiol 1978;42: Rowlatt U, Rimoldi H, Lev M. The quantitative anatomy of the normal child s heart. Pediatr Clin North Am 1963;10: Borst HG, Dalichau C. In: Borst HG, Klinner W, Semmig A, eds. Herz und herznahe Gefässe. Berlin: Springer-Verlag; 1978: Hetzer R, Delmo Walter EMB, et al. Modified surgical techniques and long term outcome of mitral valve reconstruction in 111 children. 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Am J Cardiol 1990;65: INVITED COMMENTARY Delmo Walter and colleagues [1] describe the surgical outcomes of mitral stenosis repair in patients having a normal-size left ventricle and multiple level left-sided obstructive lesions. The ages at operation ranged from 2 months to 17 years (median, 3.9 years). The mitral valve area grew from a z value of 1.9 to 1.8. Freedom from reoperation was 53%, and survival was 70% at 15 years. The highest risk for reoperation and mortality was seen in patients having (1) associated left ventricular outflow obstruction (odds ratio [OR] 10.8), (2) thickened and fused mitral leaflets (OR 10.0), and (3) parachute mitral valve (OR 4.7). Pulmonary hypertension was important (OR 2.8) but less so. Mitral disease isolated to a supramitral ring was comparatively protective (OR 0.7). Several things stand out when these data are reviewed. First, this is an effective strategy. Despite multiple mitral reoperations (32 in 14 patients), there was normal somatic growth and only one late replacement. Second, a total of 367 procedure components, in 45 patients, were performed over the course of single or multiple operations (ie, these are complex patients and operations). Third, these were not patients for whom a decision regarding a one-ventricle versus a two-ventricle repair was required; yet, good operative outcomes and documented mild or less residual mitral stenosis/regurgitation still yielded disappointing late survival (9 of 45 deceased). At least six of the deaths were thought to be non cardiac related. A plausible explanation could be that the success of treating individual components of the disease may not resolve a left-sided compliance issue. The patient could thus be vulnerable to other medical illness leading to death. It will be important for our profession to recognize that these patients will need proactive postoperative medical management despite an apparently successful operation. Glen Van Arsdell, MD Division of Cardiovascular Surgery The Hospital for Sick Children 555 University Ave, Ste 1525 Toronto, ON, Canada M5G 1X8 glen.vanarsdell@sickkids.ca Reference 1. Delmo Walter EMB, Van Praagh R, Miera O, Hetzer R. Repair of left ventricular inflow tract lesions in Shone s anomaly: valve growth and long-term outcome. Ann Thorac Surg 2013;95: by The Society of Thoracic Surgeons /$36.00 Published by Elsevier Inc