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A retrospective review in 50 patients with subaortic stenosis and intact ventricular septum: 5-year surgical experience

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We reviewed the surgical outcomes in adults and children with subaortic stenosis and intact ventricular septum in the current era. The case notes of 50 patients were reviewed for retrospective evaluation of preoperative, intraoperative and
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   ARTICLE IN PRESS www.icvts.orgdoi:10.1510/icvts.2006.141820Interactive CardioVascular and Thoracic Surgery 6 (2007) 35–38   2007 Published by European Association for Cardio-Thoracic Surgery Institutional report - Congenital A retrospective review in 50 patients with subaortic stenosis andintact ventricular septum: 5-year surgical experience Reza Barkhordarian *, Hideki Uemura , Michael L. Rigby , Babulal Sethia , Darryl Shore , a,b ,  b a b b Aruna Goebells , Siew Yen Ho b a,c Department of Paediatrics, Cardiac Morphology Unit, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK  a Department of Cardiothoracic Surgery, Royal Brompton Hospital, London, UK  b National Heart & Lung Institute, Imperial College, London, UK  c Received 10 August 2006; received in revised form 2 October 2006; accepted 4 October 2006 Abstract We reviewed the surgical outcomes in adults and children with subaortic stenosis and intact ventricular septum in the current era. Thecase notes of 50 patients were reviewed for retrospective evaluation of preoperative, intraoperative and postoperative data. Data of primary operations during the period 2000 – 2005 were compared with data from patients who had re-do surgery during the same period.Thirty-five patients had primary operation and 15 patients had re-do surgery. The median age at primary operation was eight years  ( range3 to 44 ) , at second operation was 14 years  ( range 9 to 26 )  and at third operation was 15  ( range 9 to 47 ) . The entire group had beenfollowed up postoperatively for a median of 2.5 years  ( range 0 to 5 ) . Pre-operatively, aortic regurgitation was moderate in 13 and severein three patients. Moderate to severe aortic regurgitation was present in 7  ( 20% )  patients with primary operations and 9  ( 60% )  patientswith re-do surgery  ( P  s 0.01 ) . Reviewing the first operations of all the re-dos  ( 15 patients )  in our series, one patient had myectomy andthe rest  ( 14 patients )  had isolated resection. Aortic valve regurgitation is more prevalent in patients with recurrent subaortic stenosis.Addition of myectomy is better than shelf resection only.   2007 Published by European Association for Cardio-Thoracic Surgery. All rights reserved. Keywords:  Congenital heart disease; Aortic stenosis 1. Introduction There is unresolved speculation and controversy on whyand how left ventricular outflow obstruction develops andwhen is the optimal time for surgical intervention toprevent recurrence of obstruction or aortic valve damage w 1 x . Most clinical series are on adults only or are mixedseries including patients with ventricular septal defect ormajor intracardiac anomalies  w 1 – 11,13,15 x . We herein re-viewed a group of patients  –  children and adults  –  withintact ventricular septum undergoing surgical treatment of subaortic stenosis. By excluding patients with ventricularseptal defects and additional complex anomalies, we aimto provide analysis in a group that has relatively comparablemorphology. Our aim was to compare data for primaryoperations and re-do surgery. 2. Patients and methods We retrieved case notes of all patients who underwentsurgery for relief of discrete subaortic stenosis during theperiod 2000 to 2005 at the Royal Brompton Hospital,London, for retrospective analysis  ( Table 1 ) . These patientshad subaortic stenosis and intact ventricular septum with- *Corresponding author. Tel.: q 44 207 351 8751; fax: q 44 207 351 8230. E-mail address:  r.barkhordarian@imperial.ac.uk  ( R. Barkhordarian ) . out other intracardiac lesions that could have additionaleffects on flow at the site of obstruction. Thus, we exclud-ed all patients with ventricular septal defects, those withventricular septal defects yet to be closed and those whichwere already closed, patients with hypertrophic cardiomyo-pathy and patients with anomalous insertions of the mitralvalve to the septum. Fifty patients met these criteria.Preoperative assessment was performed by echocardio-graphy in all 50 patients. Gradient across the left ventric-ular outflow tract  ( LVOT )  was calculated. For the echo-cardiographic assessment the Bernoulli equation  ( GD s 4V  ) 2 was used to derive the gradient  ( GD )  from the velocity  ( V ) .Aortic valve descriptions were obtained from the echocar-diography reports. 2.1. Statistical analysis Data are expressed as mean values. Risk factors associatedwith re-do surgery were assessed by univariate analysis.Non-parametric Mann – Whitney test was used to comparedata for primary operations and re-do surgery, and whetherpatients had myectomy or not. 3. Results There were 26 male and 24 female patients with discretesubaortic stenosis. Thirty-five patients were operated on   ARTICLE IN PRESS 36  R. Barkhordarian et al. / Interactive CardioVascular and Thoracic Surgery 6 (2007) 35–38 Table 1Subaortic stenosis  ( SAS ) , and co-existing conditionsPrimary Re-do  P  -valueoperations surgery  x 2 Number of patients 35 15Isolated SAS 18  ( 51% )  2  ( 13% )  0.027Aortic regurgitation  ( moderate to severe )  7  ( 20% )  9  ( 60% )  0.014 Aortic valve stenosis*  ( mild to severe )  4  ( 11% )  2  ( 13% )  0.776Bicuspid aortic valve* 4  ( 11% )  2  ( 13% )  0.776‘Supravalvar’ aortic stenosis 1  ( 3% )  2  ( 13% )  0.436Pulmonary stenosis  ( mild )  2  ( 6% )  1  ( 7% )  0.603Mitral stenosis  ( mild )  1  ( 3% )  0  ( 0% )  0.659Mitral regurgitation  ( mild )  1  ( 3% )  1  ( 7% )  0.875Coarctation  ( repaired )  3  ( 9% )  4  ( 27% )  0.213Patent arterial duct  ( ligated )  3  ( 9% )  2  ( 13% )  1.00*Four of the first timers had mild aortic valve stenosis. Two of them hadbicuspid aortic valve. One of the re-dos had severe aortic valve stenosis withbicuspid valve and the other had mild aortic valve stenosis with tricuspidvalve.Table 2Surgical proceduresOperations Primary operations Re-do surgery ( n s 35 ) ( n s 15 ) Shelf resection 22 2 q Myectomy 10 2 q FT mobilization 1 2 q AVR  ( Konno )  0 2 q Root  ( homograft )  0 3 q Ross 2 4FT s fibrous trigone; AVR s aortic valve replacement with mechanicalvalve ( Konno procedure ) . for the first time, seven for the second time and eight forthe third time. The 15 patients who were re-dos hadprevious resection from an earlier era between 1964 to2000. For all patients, the follow up since the last operationfor subaortic stenosis, achieved a median of 2.5 years ( range 0 – 5 years ) . For patients having re-do surgery, thefollow up since their first operation for subaortic stenosisachieved a median of 13 years  ( range 4 – 41 years ) .The median age at first operation was 8 years  ( range 3 to44 ) , at second operation was 14 years  ( range 9 to 26 )  andat third operation was 15 years  ( range 9 to 47 ) . There were32 patients in New York Heart Association functional classI, 17 in class II, and one in class III at first and repeatsurgery. Twenty-seven patients were asymptomatic.Mean Doppler echocardiographic gradient across the LVOTwas 70 " 21 mmHg. Aortic valve regurgitation was presentin 38 patients. It was mild in 22, moderate in 13, andsevere in three patients. Aortic valve stenosis was presentin six patients. Mitral stenosis was found in one patient andtwo patients had mild mitral valve regurgitation. 3.1. Surgical techniques All surgical procedures were performed with cardiopul-monary bypass. The mean operative temperature forpatients having first time surgery was 31.7 " 2.4  8 C and forpatients having redo surgery it was 28.2 " 3  8 C. Myocardialprotection was given with crystalloid or blood cardioplegia.The mean cardiopulmonary bypass time was 41 " 14.6 minand the mean crossclamp time was 27 " 11.4 min for first-time surgery. This was 109 " 60 min and 76 " 42 min for re-do surgery. The obstructive lesion was approached throughan aortotomy.Shelf resection alone was carried out in 22 patients atprimary operation and in two re-do patients, whereas shelf resection with myectomy was performed in ten patientsand two patients at primary and re-do procedures, respec-tively  ( Table 2 ) . Fibrous trigone mobilization in addition toshelf resection was carried out in three patients. Theremaining patients had aortic valve replacement withmechanical valve, or root replacement with homograft, orRoss procedure. Two of the Ross procedures were carriedout at primary operation, one at second and three at thirdoperation.There were no hospital deaths over the five-year period.Complications were: five required permanent pacemakers ( 10% risk )  and two had sternal infection re-explored, ninehad other complications  ( hypertension, infection andarrhythmias )  which resolved. The four patients needing re-operations within five years were for residual gradient ( G 30 mmHg ) ( 1 first-timer ) , drainage of pericardial effu-sion  ( 1 first-timer ) , emergency exploration for cardiacarrest  ( 1 third-timer )  and ventricular fibrillation and rightheart failure needing a coronary bypass graft  ( 1 third-timer ) . 3.2. Echocardiographic gradient The preoperative LVOT echocardiographic gradient wasreduced from 65 " 18.7 mmHg to 19 " 10.5 mmHg in first-timers and from 82 " 21.8 mmHg to 26.9 " 9.1 mmHg in re-dos after surgery. At the last available follow up thepostoperative LVOT echocardiographic gradient was30 " 24.6 mmHg and 31.3 " 13.7 mmHg for patients havingsurgery for the first time and re-do surgery, respectively.Amongst the primary operations three patients had gradient G 30 mmHg in the immediate postoperative period  ( theyhad subaortic stenosis resection only )  and six patients atthe last echocardiographic data available. Amongst the re-dos, four patients had gradient  G 30 mmHg at immediatepostoperative period and two patients at last echocardio-graphy. 3.3. Aortic valve function Sixteen patients had moderate to severe aortic regurgi-tation before operation. These were seven patients atprimary operation and nine patients at re-do. The ninepatients in the re-do group had aortic valve procedures ( four Ross procedures, two aortic valve replacements andthree root replacements )  and the rest had subaortic ste-nosis resection. Aortic valve repair was not performed inany patient. 3.4. Recurrence In total, fifteen patients  ( 30% )  were having re-do surgery.Reviewing the first time operations of all the re-dos  ( 15patients )  in our series, only one patient had myectomy andthe rest  ( 14 patients )  had isolated resection.   ARTICLE IN PRESS 37 R. Barkhordarian et al. / Interactive CardioVascular and Thoracic Surgery 6 (2007) 35–38 4. Discussion There were no deaths in our series but in a combinedseries of 314 patients compiled from the literature withsubaortic surgery in an earlier era, mortality was around5%  w 7 x . Those patients with previous moderate to severeaortic regurgitation are more likely to have re-do surgeryfor subaortic stenosis. 4.1. Aortic valve Multifactorial aetiologies have been put forward for devel-opment of aortic regurgitation in association with subaorticstenosis: involvement of aortic valve leaflets by the shelf lesion, leaflet distortion by turbulent blood flow, infectiveendocarditis, cusp thickening from poststenotic turbulence,etc. w 1 – 3 x .Some reports have suggested that aortic regurgitationmay progress after surgery for subaortic stenosis whileothers have suggested that aortic regurgitation remainstrivial or mild unless endocarditis occurs w 4,7 x .Preoperatively, in the first-timers there were sevenpatients  ( 20% )  and in re-dos nine patients  ( 60% )  withmoderate to severe aortic regurgitation  ( Table 1 ) . Overall,32% of patients had moderate to severe aortic regurgitationpreoperatively compared to none postoperatively. We agreewith Serraf and colleagues that relief of subvalvar aorticstenosis reduces the degree of aortic regurgitation in thesepatients  w 12 x . Early surgery seems to prevent aortic valvedisease in our cohort, in concordance with Brauner andcolleagues w 13 x .Since our study is a five-year retrospective study, thefollow-up might not be long enough to include late devel-opment of aortic regurgitation postoperatively.A major proportion of patients who had re-do surgery forsubaortic stenosis with intact ventricular septum alsorequired valve replacements  ( Table 2 ) .We agree with Shem-Tov et al.  w 5 x  that, because of theprogressive nature of left ventricular outflow tract obstruc-tion, it is unreasonable to use the same echocardiographicpressure gradient  ( 50 mmHg )  criteria for surgery as thoseused for valvar aortic stenosis. In view of high incidence of aortic regurgitation with subaortic stenosis and low mor-tality w 7,11 – 13 x associated with surgery, we suggest the useof a milder echocardiographic gradient  ( 40 mmHg andabove in asymptomatic and 30 mmHg and above in symp-tomatic patients )  as an indication for surgery. 4.2. Recurrence Seven patients were presenting for the second time andeight patients were presenting for the third time. Lupinettiand colleagues  w 8 x  ( 40 patients with 12 years follow up ) and Rayburn and colleagues w 9 x  ( 23 patients with 14 yearsfollow up )  recommended the addition of septal myectomyto shelf resection in order to reduce the frequency of reoperation. In those without myectomy, the LVOT gradientincreased postoperatively at a greater rate than those withmyectomy.Furthermore, in our series there was a significant differ-ence for preoperative LVOT gradient between first-timersand re-dos. There were more patients in the re-do groupwith immediate postoperative gradient in LVOT 30 mmHgthan first-timers. It is important to pay attention to imme-diate postoperative gradient as recurrence, reoperation,and mortality can be influenced by residual postoperativeleft ventricular outflow gradient  w 7,12 x . Prior coarctationrepairs were 3  ( 9% )  at primary operation and 4  ( 27% )  atre-do surgery with a  P  -value of 0.21. A large prospectivestudy is needed to analyse the relative risk of recurrencein the setting of associated coarctation. We have excludedpatients with ventricular septal defects and major cardiacanomalies as they can contribute to turbulent fluid shearstress and proliferation. The effect of coarctation as acontributing factor into turbulence in the left ventricularoutflow tract needs to be investigated in further studies.Stewart and colleagues, with a ‘mixed’ series, reported50% of their patients including those with ventricular septaldefect required reoperation, some more than 15 years afterthe initial surgery, while de Vries and colleagues foundrecurrence of stenosis and progression of aortic regurgita-tion in as high as 55% of cases. Brauner and colleaguesfound 20% recurrence over 6.7 years and, despite relief of obstruction, progressive aortic regurgitation was noted in40% of those with echocardiographic gradient  G 40 mmHgcompared with only 12.5% of those with gradient F 40 mmHg, suggesting that early intervention or moreextensive surgery might prevent recurrence, reoperationand aortic valve damage w 13 x .Subaortic stenosis surgery has a very low mortality inspecialized units  w 10 – 14 x . Early surgery and at a lowergradient  ( 30 mmHg )  have been recommended to preventthe development of aortic regurgitation and improve results w 10,13 x . Some surgeons even advocate surgery for subvalvarstenosis at the time of diagnosis  w 15 x , although this doesnot prevent the recurrence of subaortic stenosis in the longterm. Close long-term follow up of 10 – 30 years is neededsince recurrence can occur nearly thirty years after initialsurgery. 4.3. Limitations The retrospective nature of this study may be consideredan important limitation, and the data should be confirmedby prospective studies. This study is based on the experi-ence of one tertiary unit limiting patient numbers andpatient selection to local practice.A further limitation is the relatively short period of followup  ( five years with median of 2.5 years ) . Many previousstudies mixed isolated discrete subaortic stenosis with casesthat had additional complex cardiac lesions w 1,6 – 11,13,15 x .Extending this type of study to multicentres will allowcomparisons of working practices such as indications forsurgery and type of surgery that will allow consistent andcoherent guidelines to be constructed to treat this groupof patients. 5. Conclusions A major proportion of patients who have reoperation forsubaortic stenosis also require valve replacement becauseof moderate to severe aortic regurgitation. We emphasizethe need for earlier repair and need for concomitantmyectomy.   ARTICLE IN PRESS 38  R. Barkhordarian et al. / Interactive CardioVascular and Thoracic Surgery 6 (2007) 35–38 Acknowledgments We thank Philip Kimberly for his assistance in retrievingthe cases. The Cardiac Morphology unit receives fundingfrom the Royal Brompton and Harefield Hospital CharitableFund. References w 1 x  Newfeld EA, Muster AJ, Paul MH, Idriss FS, Riker WL. 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J AmColl Cardiol 2001;38:835 – 842. w 7 x  Kouchoukos NT, Blackstone EH, Doty DB, Hanley FL, Karp RB. In: KirklinJW, Barratt-Boyes BG  ( eds ) . Cardiac Surgery, 3rd edn. Edinburgh:Churchill Livingstone; 2003, p. 1265 – 1313. w 8 x  Lupinetti FM, Pridjian AK, Callow LB, Crowley DC, Beekman RH, BoveEL. Optimum treatment of discrete subaortic stenosis. Ann Thorac Surg1992;54:467 – 470. w 9 x  Rayburn ST, Netherland DE, Heath BJ. Discrete membranous subaorticstenosis: improved results after resection and myectomy. Ann ThoracSurg 1997;64:105 – 109. w 10 x  Parry AJ, Kovalchin JP, Suda K, McElhinney DB, Wudel J, Silverman NH,Reddy VM, Hanley FL. Resection of subaortic stenosis; can a moreaggressive approach be justified? Eur J Cardiothorac Surg 1999;15:631 – 638. w 11 x  Coleman DM, Smallhorn JF, McCrindle BW, Williams WG, Freedom RM.Postoperative follow-up of fibromuscular sub-aortic stenosis. J Am CollCardiol 1994;24:1558 – 1564. w 12 x  Serraf A, Zoghby J, Lacour-Gayet F, Houel R, Belli E, Galletti L, PlancheC. Surgical treatment of subaortic stenosis: a seventeen-year experi-ence. J Thorac Cardiovasc Surg 1999;117:669 – 678. w 13 x  Brauner R, Laks H, Drinkwater DCJ, Shvarts O, Eghbali K, Galindo A.Benefits of early surgical repair in fixed subaortic stenosis. J Am CollCardiol 1997;30:1835 – 1842. w 14 x  Vouhe PR, Poulain H, Bloch G, Loisance DY, Gamain J, Lombaert M,Quiret JC, Lesbre JP, Bernasconi P, Pietri J. Aortoseptal approach foroptimal resection of diffuse subvalvular aortic stenosis. J ThoracCardiovasc Surg 1984;87:887 – 893. w 15 x  Wright GB, Keane JF, Nadas AS, Bernhard WF, Castaneda AR. Fixedsubaortic stenosis in the young: medical and surgical course in 83patients. Am J Cardiol 1983;52:830 – 835.
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