Doubly committed or subarterial ventricular septal. Tetralogy of Fallot With Subarterial Ventricular Septal Defect

Transcription

1 ORIGINAL ARTICLES: Tetralogy of Fallot With Subarterial Ventricular Septal Defect Makoto Ando, MD, Yukihiro Takahashi, MD, Toshio Kikuchi, MD, and Katsuhiko Tatsuno, MD Department of Pediatric Cardiac Surgery, Sakakibara Heart Institute, Tokyo, Japan Background. Tetralogy of Fallot with subarterial ventricular septal defect is frequently seen among Asians. Compared with infracristal ventricular septal defect, postoperative right ventricular outflow obstruction is more likely because of subpulmonary extension of the defect. Moreover the incidence of aortic regurgitation is a concern because of the absence of a supporting infundibulum. Methods. Four hundred cases of classic tetralogy were reviewed, 61 of which had subarterial ventricular septal defect. Results. Aortic regurgitation (of more than mild degree) was identified in 7 cases with subarterial and 7 with infracristal ventricular septal defects. The mechanism of infracristal defect was predominantly an annular dilation before surgery. In contrast 5 cases with subarterial defect had progression of aortic regurgitation after operation yielding an actuarial incidence of 29.7% at 20 years. In 2 patients the cause seemed to be fixation or plication of the aortic valve annulus by the ventricular septal patch. Compared with infracristal defect, subarterial defect was associated with increased incidence of reoperation (12.0% versus 1.9% at 10 years, p 0.01), frequent use of transannular patch (70.5% versus 45.7%, p ), and worse New York Heart Association (NYHA) functional class (p 0.007). Right ventricular outflow obstruction was the reason for reoperation in 3 patients with subarterial defect and was associated with worse NYHA classification in the long-term, on multivariate analysis (p ). Conclusions. Tetralogy with subarterial ventricular septal defect was associated with worse functional outcome. To prevent adverse outcomes, precise suturing of the distal ventricular septal patch, extensive infundibulectomy, lower threshold for transannular incision, and smaller-sized ventricular septal patch placement are warranted. (Ann Thorac Surg 2003;76: ) 2003 by The Society of Thoracic Surgeons Doubly committed or subarterial ventricular septal defect (VSD) is frequently seen among Asians. An isolated form of this defect is well known to be associated with prolapse of the right and noncoronary cusps and aortic regurgitation [1]. In Japanese patients, the reported incidence of tetralogy of Fallot (TOF) with subarterial VSD is about 10% to 20% [2, 3], which is higher than the incidence among Western people [4, 5]. Although prolapse of the aortic valve is less frequent [6, 7], the fate of the aortic valve not supported by a muscular infundibulum after total repair is unknown. Because of subpulmonary extension of the ventricular septal defect, relief of the right ventricular outflow obstruction is difficult in TOF with subarterial VSD [8]. Moreover accurate suturing of the VSD patch may warrant an extra incision on the right ventricle. Therefore both the right and left ventriculoarterial junctions are at increased risk of insult and this can jeopardize the postoperative outcome of TOF with subarterial VSD. Presented at the Thirty-ninth Annual Meeting of The Society of Thoracic Surgeons, San Diego, CA, Jan 31 Feb 2, Address reprint requests to Dr Ando, Department of Pediatric Cardiac Surgery, Sakakibara Heart Institute, Yoyogi, Shibuya-Ku, Tokyo , Japan; maando@shi.heart.or.jp. In this article we retrospectively reviewed specific anatomical features of TOF with subarterial VSD and compared postoperative outcome for this anomaly with that for TOF with infracristal VSD. Patients and Methods Hospital and outpatient records of 400 consecutive cases of classic TOF undergoing total repair between April 1978 and January 2002 were reviewed. A questionnaire, which was approved by our Institutional Review Board, was sent to the referring physician if the patient was not followed at our outpatient clinic. Tetralogy of Fallot associated with pulmonary atresia, absent pulmonary valve, or complete atrioventricular septal defect was excluded. Preoperative variables used to predict postoperative adverse outcomes included principal diagnosis (TOF with subarterial VSD or TOF with infracristal VSD), chronological order of operation, sex, age and body weight at operation, Nakata s pulmonary artery index [9], additional cardiac diagnosis, presence of noncardiac anomaly, and former systemic-to-pulmonary shunt placement. Operative variables analyzed included cardiopulmo by The Society of Thoracic Surgeons /03/$30.00 Published by Elsevier Inc PII S (03)

2 1060 ANDO ET AL Ann Thorac Surg TETRALOGY WITH SUBARTERIAL VSD 2003;76: Table 1. Demographic and Outcome Variables With Univariate p Values Variable Subarterial VSD Infracristal VSD p Value Preoperative Body weight (kg) Age (years) Pulmonary artery index Presence of noncardiac anomaly 1 (1.6%) 23 (6.8%) 0.12 Previous systemic-pulmonary shunt 17 (27.9%) 125 (36.9%) 0.18 Additional cardiac diagnosis 8 (13.1%) 30 (8.8%) 0.30 Sex (female/male) 25/36 148/ Intraoperative Transannular patching 43 (70.5%) 155 (45.7%) Cardiopulmonary bypass time (min) Presence of dysplastic pulmonary valve 7 (11.5%) 47 (13.9%) 0.62 Myocardial ischemic time (min) Surgeon (A/B/C) 31/15/15 169/76/ Postoperative Aortic valve regurgitation ( mild) 7 (11.7%) 7 (2.1%) Reoperation 5 (8.2%) 6 (1.8%) NYHA functional class I 53 (88.3%) 324 (96.4%) Postoperative PR (0 4) Use of cardiac medication 11 (18.3%) 43 (12.8%) 0.25 Postoperative RVp/LVp Mortality 1 (1.6%) 3 (0.8%) 0.59 Postoperative complication 7 (11.5%) 32 (9.4%) 0.62 Arrhythmia 1 (1.7%) 9 (2.7%) 0.64 Data presented are mean standard deviation or number with percentages in parentheses. NYHA New York Heart Association; PR pulmonary valve regurgitation; RVp/LVp systolic pressure ratio of the right ventricle to the left ventricle; VSD ventricular septal defect. nary bypass time, myocardial ischemic time, surgeon (A, B, or C), use of transannular patch, and presence of dysplastic pulmonary valve. Dysplasty of the pulmonary valve was defined as the presence either of severe commissural fusion of the leaflets with pinhole opening of the orifice, severe asymmetry of the leaflets, or very thick leaflets without normal excursion. Postoperative variables used as outcome measures included incidence of aortic regurgitation, postoperative complication seen during the initial hospitalization, systolic pressure ratio of the right ventricle to the left ventricle (RVp/LVp) obtained before initial discharge and on the most recent echocardiogram, the degree of pulmonary regurgitation obtained before initial discharge and on the most recent echocardiogram, use of cardiac medication, ventricular or atrial arrhythmia requiring medication, mortality, reoperation, and New York Heart Association (NYHA) functional classification at the latest follow-up. Cardiac medications included digoxin, diuretics, and antiarrhythmics. The surgical approach varied over time during the study period. Before 1991 the VSD was primarily closed from a right ventriculotomy. Since 1992 transatrialtranspulmonary repair has been employed whenever possible. The age at repair has become younger, and recent policy is to perform repair before the age of 2 years, regardless of the anatomy. Right ventricular pressure had been measured by direct needle insertion; more recently it has been estimated by measuring the maximal flow velocity of tricuspid regurgitation using Doppler echocardiography. Statview statistical software for Windows (version 4.5; Abacus Concepts, Berkeley, CA) was used for data analysis. Values were expressed as mean SD. Univariate analysis was performed using either the Student s t test or the 2 test, as appropriate. Survival analysis was done using the Kaplan-Meier product limited method. Intergroup comparisons were made using the log-rank test. Factors found to have significance (p 0.05) on univariate analysis were selected for final multivariate logistic regression analysis. Results The mean follow-up period was years (3,569.2 patient years). Follow-up was complete in 360 patients (90%). Sixty-one patients (15.3%) had TOF with subarterial VSD and 339 had TOF with infracristal VSD. Representative preoperative, operative, and postoperative variables are summarized in Table 1. Patients with TOF with subarterial VSD were significantly older and had larger body weight compared with TOF with infracristal VSD. Pulmonary artery size tended to be larger with TOF with subarterial VSD but the

3 Ann Thorac Surg ANDO ET AL 2003;76: TETRALOGY WITH SUBARTERIAL VSD 1061 Table 2. Additional Cardiac Diagnoses (n 39) Diagnosis Subarterial VSD Infracristal VSD Total Anomalous coronary artery Tricuspid valve regurgitation ( moderate) Aortic valve regurgitation ( moderate) Total/partial anomalous 4 4 pulmonary venous return Interrupted branch pulmonary artery Additional muscular ventricular septal defect PLSVC draining into the left 2 2 atrium Pulmonary valsalva 1 1 aneurysm Discrete subaortic stenosis 1 1 Mitral valve regurgitation 1 1 ( moderate) Major aortopulmonary 1 1 collateral artery Hypoplastic right ventricle 1 1 Recent myocardial infarction 1 1 Annuloaortic ectasia 1 1 Congenital heart block 1 1 Double aortic arch 1 1 PLSVC persistent left superior vena cava; defect. VSD ventricular septal difference was statistically borderline, with a p value of Additional cardiac diagnoses are listed in Table 2. Noncardiac anomalies were seen in 24 patients. Twentythree of these were present in patients with TOF with infracristal VSD, including Down s syndrome (n 18) and 1 case each of the following: hydronephrosis, absence of a kidney, pulmonary sequestration, funnel chest, and diaphragmatic hernia. Noonan syndrome was the only noncardiac anomaly seen in a patient with TOF with subarterial VSD. Transannular patch was more frequently used in TOF with subarterial VSD (70.5%) compared with TOF with infracristal VSD (45.7%). There were 2 early deaths ( 30 days) and 2 late deaths, yielding actuarial survivals of 99.2% at 5 years and 98.7% from 10 through 20 years. Three deaths occurred in patients with TOF with infracristal VSD. The first patient developed cerebral venous thrombosis demonstrated on computed tomographic scan and died on postoperative day 1. The second patient developed severe cardiac failure, which was further complicated by bleeding from the lung; this patient died on day 3. The third patient had postoperative bleeding resulting in late cardiac tamponade causing cardiac failure and died on day 33. One female patient with TOF with subarterial VSD was found dead in her house at 7.9 years after operation. This patient was in NYHA class III but no definite cause was identified. There was no statistical difference in actuarial survival between the two groups (p 0.61). Fig 1. Kaplan-Meier estimated freedom from reoperation (FFR). The open markers indicate FFR for patients with tetralogy of Fallot with subarterial ventricular septal defect. The solid markers indicate patients with infracristal ventricular septal defect. Vertical bars indicate the lower 95% confidence intervals. The number of patients at risk are shown in parentheses (infracristal ventricular septal defect, upper row; subarterial ventricular septal defect, lower row). The FFR curves are significantly different (p 0.01; log-rank test). Acute postoperative complications during the initial hospitalization were seen in 39 patients including the 3 deaths with TOF with infracristal VSD. Congestive heart failure (defined as dependence on catecholamine infusion or mechanical ventilation, or having persistent pleural effusion for more than 7 days) was seen in 34 patients 6 with TOF with subarterial VSD and 28 with TOF with infracristal VSD. Surgical atrioventricular block was seen in 1 patient with TOF with subarterial VSD. This patient required epicardial pacemaker insertion at the time of reoperation. Another patient with TOF with infracristal VSD developed cardiac arrest of unknown cause and required resuscitation; this patient recovered without a further event. Postoperative variables that had significant difference between TOF with subarterial VSD and TOF with infracristal VSD included incidence of aortic regurgitation, NYHA functional class, and incidence of reoperation. Eleven patients required reoperation. The indication for reoperation with TOF with infracristal VSD included repair of the branch pulmonary artery stenosis in 3 patients, aortic valve replacement in 1, pulmonary valve replacement in 1, and relief of the pulmonary venous obstruction in 1 patient (after repair of total anomalous pulmonary venous return). In contrast right ventricular outflow tract obstruction at the level of the distal VSD patch was the most frequent cause of reoperation for patients with TOF with subarterial VSD and was seen in 3 cases; 2 of these had dehiscence of the VSD patch, which was repaired at the same time. Indications for reoperation in the other 2 patients with TOF with subarterial VSD were aortic valve replacement and repair of the branch pulmonary artery stenosis. Overall freedom from reoperation was 98.2% at 5 years, 97.2% at 10 years,

4 1062 ANDO ET AL Ann Thorac Surg TETRALOGY WITH SUBARTERIAL VSD 2003;76: Table 3. Multiple Logistic Regression Risk Analysis for Worse NYHA Functional Class Variables Coefficient ( ) SE Wald 2 p Value Postoperative RVp/LVp Acute complication Late arrhythmia Aortic regurgitation Cardiac complication Body weight Cardiopulmonary bypass time Myocardial ischemic time VSD (subarterial/infracristal) Age Fig 2. Kaplan-Meier estimated actuarial incidence of aortic valve regurgitation (AIAR) of more than mild degree. The open markers indicate AIAR for patients with tetralogy of Fallot with subarterial ventricular septal defect. The solid markers indicate patients with infracristal ventricular septal defect. Vertical bars indicate the upper 95% confidence intervals. The number of patients at risk are shown in parentheses (subarterial ventricular septal defect, upper row; infracristal ventricular septal defect, lower row). The AIAR curves are significantly different (p ; log-rank test). and 94.9% from 15 through 20 years. By group it was 92.8% at 5 years and 88.0% at 10 years for TOF with subarterial VSD, and 99.2% at 5 years and 98.1% at 10 years for TOF with infracristal VSD (Fig 1). The p value of this difference was Fourteen patients developed more than mild aortic regurgitation during the study period 7 with TOF with subarterial VSD and 7 with TOF with infracristal VSD. In 6 patients with TOF with infracristal VSD, aortic regurgitation was present before operation. Only 1 patient developed aortic regurgitation after operation, at 11 months. The uniform finding was an annular dilation although 1 patient had a coexisting bicuspid valve. One had severe regurgitation and eventually required aortic valve replacement. The actuarial incidence of aortic regurgitation (more than mild) for patients with TOF with infracristal VSD was 2.1% from more than 11 months to 20 years. Conversely the etiologies of aortic regurgitation for patients with TOF with subarterial VSD seemed to be diverse. One patient had a quadricuspid valve and eventually required aortic valve replacement (at 8 months). Prolapse of the right coronary cusp was identified in 1 patient; regurgitation in this patient was mild and diminished with suspension of the leaflet at the time of repair. Five patients developed aortic regurgitation after operation even though the valve was intact at the time of repair. Prolapse of the left and noncoronary cusps was found in 2 patients and the regurgitation jet was directed toward the interventricular septum. In the other 3 patients the etiology was not identified. The actuarial incidence of aortic regurgitation (more than mild) was 3.3% Variables that were identified to be a risk on univariate analysis are listed. NYHA New York New Association; RVp/LVp systolic pressure ratio of the right ventricle to the left ventricle; SE standard error of the mean; VSD ventricular septal defect; Wald 2 Wald test statistic calculated from the data to be compared with the chi-square distribution with one degree of freedom. at 5 years, 10.8% at 10 and 15 years, and 29.7% at 20 years for patients with TOF with subarterial VSD. The p value of the difference between two groups was (Fig 2). Among patients with TOF with subarterial VSD, 11.7% were in NYHA class II or III at the time of last follow-up compared with 3.6% of patients with TOF with infracristal VSD (p 0.007). The follow-up period was similar between TOF with subarterial VSD ( years) and TOF with infracristal VSD ( years) (p 0.23). The actuarial percentage of the patients on cardiac medication was 8.9% at 20 years for patients with TOF with subarterial VSD and 2.8% with infracristal VSD, although this difference did not reach significance (p 0.14). Tetralogy of Fallot with subarterial VSD repaired without transannular patch had a higher postoperative RVp/ LVp on the most recent echocardiogram ( ) compared with other groups ( , p ). Multiple logistic regression analysis identified four significant risk factors for worse NYHA functional class with the strongest being the postoperative RVp/LVp, followed by acute complication, late arrhythmia, and aortic regurgitation (more than mild; Table 3). Comment Tetralogy of Fallot with subarterial VSD is characterized by its unique geographic distribution, namely around Eastern Asia [2, 3]. The correction of this anomaly has been associated with increased mortality compared with TOF with infracristal VSD [10]. In the present study however overall mortality rate and actuarial survival were similar between TOF with subarterial VSD and TOF with infracristal VSD. It has been a subject of debate whether this can be called tetralogy because the traditional definition required anterior deviation of the muscular outlet septum,

5 Ann Thorac Surg ANDO ET AL 2003;76: TETRALOGY WITH SUBARTERIAL VSD 1063 Fig 3. An estimated mechanism of late aortic regurgitation. Deep stitches on the distal ventricular septal patch (arrow) can fix or plicate the aortic valve annulus adjacent to the right coronary cusp (A). This can interfere with growth of this leaflet (arrows) and may cause prolapse and regurgitation in the long-term (B). which is absent with subarterial VSD [11]. As anterior displacement of the fibrous raphe between the arterial valves produces hemodynamic characteristics consistent with TOF with infracristal VSD, this entity is generally categorized as a tetralogy variant nowadays [12]. It is known that with an isolated subarterial VSD prolapse of the right or noncoronary cusp can cause aortic regurgitation [13]. It is generally thought that because of dominant right to left shunt at early systole deformity of the aortic valve is subtle with TOF [6]. Because the aortic valve receives blood from both ventricles before operation annular dilation can cause aortic regurgitation for patients with TOF. Dodds [14] reported an increased incidence of aortic regurgitation after repair of TOF with pulmonary atresia. The incidence has been lower with classic TOF [15, 16]. The present data reveal that the etiology of aortic regurgitation with TOF with infracristal VSD was predominantly annular dilation, which rarely progresses after surgery. However late aortic regurgitation after repair is possible with TOF with subarterial VSD. Two patients with TOF with subarterial VSD in whom developed late aortic regurgitation obviously had prolapse of the left and noncoronary cusps. We speculate that fixation or plication of the aortic valve annulus adjacent to the right coronary cusp caused by ventricular septal patch placement interferes with the growth of this leaflet. Consequently the leaflets may become asymmetrical and eventually develop prolapse and regurgitation with somatic growth (Fig 3). Very accurate suturing of the distal VSD patch with stitches confined to the pulmonary valve annulus may be the key to preventing this phenomenon. Because of the absence of an obstructing distal infundibulum TOF with subarterial VSD may be associated with better growth of the pulmonary artery. Pulmonary artery size tended to be better compared with TOF with infracristal VSD. To achieve more precise surgery one might consider complete repair of TOF with subarterial VSD later in the life of the patient. The attenuated limb of the septal band usually merges Fig 4. An adequate sized ventricular septal patch leaves the right ventricular outflow tract patent (A). In contrast an oversized patch with redundancy left at the distal end can obstruct the outflow tract (B). posteriorly with a thin ventriculoinfundibular fold in TOF with subarterial VSD. Fibrous continuity may exist between tricuspid and aortic valves (total conus defect). Consequently the ventricular septal plane or the right ventricular inflow axis crosses perpendicular to the outflow axis. On an angiogram the subarterial infundibulum protrudes into the right ventricular shadow in an anteroposterior projection, which others call beak-neck shadow [6]. Therefore an oversized patch or a redundancy left at the distal patch can result in further obstruction of the right ventricular outflow tract (Fig 4). Infundibulectomy is confined to the free wall side of the right ventricle at this level and has to be done generously to avoid a long transannular patch placement. Vargas [17] reported that TOF with subarterial VSD was more likely to have a nonrestrictive pulmonary annulus and to be repaired without a transannular patch. In contrast others report that pulmonary annulus size is similar to TOF with infracristal VSD and that transannular patch placement is almost mandatory [6]. In our cohort 70.5% required transannular patch for TOF with subarterial VSD. Furthermore TOF with subarterial VSD repaired without transannular patch resulted in a higher postoperative RVp/LVp. We believe that more liberal use of a transannular patch is still justified in the repair of TOF with subarterial VSD. Anterior and posterior ends of the fibrous tissue between the aortic and pulmonary annuli merge with attenuated limbs of the septal band. Suturing of the VSD patch is especially difficult at these points both from the right atrium and the pulmonary artery because of the sharply angled turn. Instead of extending the transannular incision we prefer to place an isolated transverse incision on the right ventricle to expose these points. This incision is closed primarily and is therefore unlikely to compromise right ventricular function. There are multiple limitations to the study. This was a retrospective study and the surgical approach varied over its duration. Moreover surgical approach might have varied at the discretion of the three different surgeons involved. The accuracy of estimated RVp/LVp depends significantly on the hand of the interpreter. The

6 1064 ANDO ET AL Ann Thorac Surg TETRALOGY WITH SUBARTERIAL VSD 2003;76: measurement is qualitative and may be sufficiently subjective to introduce bias. This effect may be even more prominent in the assessment of pulmonary regurgitation. Many angiograms and echocardiograms had poor images from which to attempt reliable measurements of pulmonary arterial annulus size. Thus this potentially useful information could not be incorporated into the data analysis. In summary both TOF with subarterial VSD and TOF with infracristal VSD had low perioperative mortality and morbidity. An excellent long-term outcome can be expected after repair of TOF with infracristal VSD. In contrast TOF with subarterial VSD was associated with worse functional outcome. The present study was consistent with other reports demonstrating that residual subarterial obstruction was the main reason for reoperation in TOF with subarterial VSD and that transannular incision was required in significant proportion. In the long term a higher RVp/LVp was closely associated with worse NYHA functional class. Aortic regurgitation associated with TOF with infracristal VSD may be eliminated by early repair because preoperative annular dilation seems responsible. Conversely late aortic regurgitation after repair can develop in patients with TOF with subarterial VSD. Fixation or plication of the right coronary cusp may be one cause of this phenomenon. Accurate surgery with precise suturing of the distal ventricular septal patch, extensive infundibulectomy, lower threshold to place a transannular patch, and usage of a smaller-sized ventricular septal patch are warranted in order to prevent adverse outcomes. References 1. De Leval MR, Pozzi M, Starnes V, et al. Surgical management of doubly committed subarterial ventricular septal defects. Circulation 1988;78(Suppl 3): Oguni H, Satomi G, Yamada Y, Hatano T, Nakamura K, Takao A. Two-dimensional echocardiographic diagnosis of tetralogy of Fallot with a total conus defect. J Cardiogr 1983;13: Ando M. Subpulmonary ventricular septal defect with pulmonary stenosis. Circulation 1974;50: Anderson RH, Allwork SP, Ho SY, Lenox CC, Zuberbuhler JR. Surgical anatomy of tetralogy of Fallot. J Thorac Cardiovasc Surg 1981;81: Goel PK, Shahi M, Mahant TS, Mittal PK, Radhakrishnan S. Absent conal septum in tetralogy of Fallot. An angiographic study. Angiology 1997;48: Kurosawa H, Yanagisawa M, Kainuma Y, et al. Tetralogy of Fallot with total conus defect. Jpn J Thorac Surg 1976;29: Matsuda H, Ihara K, Mori T, Kitamura S, Kawashima Y. Tetralogy of Fallot associated with aortic insufficiency. Ann Thorac Surg 1980;29: Neirotti R, Galindez E, Kreutzer G, Rodriguez Coronel A, Pedrini M, Becu L. Tetralogy of Fallot with subpulmonary ventricular septal defect. Ann Thorac Surg 1978;25: Nakata S, Imai Y, Takanashi Y, et al. A new method for the quantitative standardization of cross-sectional areas of the pulmonary arteries in congenital heart diseases with decreased pulmonary blood flow. J Thorac Cardiovasc Surg 1984;88: Okita Y, Miki S, Ueda Y, et al. Early and late results of repair of tetralogy of Fallot with subarterial ventricular septal defect. J Thorac Cardiovasc Surg 1995;110: Griffin ML, Sullivan ID, Anderson RH, Macartney FJ. Doubly committed subarterial ventricular septal defect: new morphologic criteria with echocardiographic and angiographic correlation. Br Heart J 1988;59: Jacobs ML. Congenital heart surgery nomenclature and database project: tetralogy of Fallot. Ann Thorac Surg 2000; 69:S Tatsuno K, Konno S, Ando M, Sakakibara S. Pathogenetic mechanism of prolapsing aortic valve and aortic regurgitation associated with ventricular septal defect. Circulation 1973;68: Dodds GA, Warnes CA, Danielson GK. Aortic valve replacement after repair of pulmonary atresia and ventricular septal defect or tetralogy of Fallot. J Thorac Cardiovasc Surg 1997;113: Pomè G, Rossi C, Colucci V, et al. Later reoperations after repair of tetralogy of Fallot. Eur J Cardiothorac Surg 1992;6: Zahka KG, Horneffer PJ, Rowe SA, et al. Long-term valvular function after total repair of tetralogy of Fallot. Relation to ventricular arrhythmias. Circulation 1988;78(Suppl 3): Vargas FJ, Kreutzer GO, Pedrini M, Capelli H, Rodriguez Coronel A. Tetralogy of Fallot with subarterial ventricular septal defect. Diagnostic and surgical considerations. J Thorac Cardiovasc Surg 1986;92: DISCUSSION DR JOHN E. MAYER, JR (Boston, MA): Why is this any different in the way you have managed the ventricular septal defect in patients who have an isolated subpulmonary ventricular septal defect? Have you seen the same problems with late aortic regurgitation due to fixation of the right coronary cusp in patients who have an infundibular or subpulmonary ventricular septal defect as an isolated lesion? DR ANDO: Actually, with an isolated VSD, because the VSD is running more parallel to the main pulmonary artery axis, and the VSD size itself is a little bit smaller, we always try to close it exclusive from the pulmonary artery. And it is possible in the majority of cases. With regard to late aortic regurgitation, I am not realizing that it is happening after repair of an isolated VSD. A couple of estimations exist. One is with tetralogy of Fallot; the root plication is thought to be one of the mechanisms for late AR. But with an isolated VSD, this may be not causing such a harm, because there is always a redundancy of the right coronary cusp exists. That is one reason. Another reason is because an annular dilation before surgery exists in tetralogy/subarterial VSD, this may be causing some degree of vascular medial injury in these patients. And this may be making the aortic valve more vulnerable to a surgical insult. These are the couple of things that I am estimating. DR GERHARD ZIEMER (Tuebingen, Germany): In your summary, in order to achieve best results, you suggest to perform accurate surgery and have a low threshold for placing a transannular patch. Accurate surgery in your hands includes extensive infundibulectomy. If you combine both transannular patch and extensive infundibulectomy, I think this is a guarantee to get an outflow tract aneurysm at some point with or without major

7 Ann Thorac Surg ANDO ET AL 2003;76: TETRALOGY WITH SUBARTERIAL VSD 1065 regurgitation. So in my experience it should be either transannular patch or extensive infundibulectomy. But if you combine both, I would regard this as being not the best surgical treatment possible. DR ANDO: Maybe if you resect the muscle too much, you can cause an aneurysm. But with a very adequate excising, I think it does not happen. DR RALPH S. MOSCA (New York, NY): You alluded to it in your summary; perhaps you can clarify for us. Since the aortic insufficiency was progressive, do you think that operating at an earlier might alleviate most if not all of this associated aortic regurgitation? DR ANDO: Aortic regurgitation associated with tetralogy/ PMVSD, we think, is caused by annular dilatation that exists before operation. Therefore, as long as an intrinsic deformity of the valve does not exist, AR could be eliminated by an early repair. Another thing is that a right coronary cusp prolapse, which is seen in a fraction of patients with tetralogy/subarterial VSD, may be also eliminated by indication of repair at an earlier age.