T ciated with atrioventricular (AV) discordance have

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1 Tricuspid Valve Abnormalities in Patients With Atrioventricular Discordance: Surgical Implications Pave1 Horvath, MD, Marek Szufladowicz, MD, Marc R. de Leval, MD, Martin J. Elliott, MD, and Jaroslav Stark, MD Cardiothoracic Unit, The Hospital for Sick Children, and Harley Street Clinic, London, England From 1975 to 1990,90 patients (age, 6 months to 30 years; mean, 9.1 years) underwent operation for defects associated with atrioventricular discordance. Twenty-one had an anatomically abnormal tricuspid (systemic) atrioventricular valve (SAVV) of the following types: Ebstein, 11; straddling, 6; and dysplastic, 4. Sixteen valves were regurgitant: regurgitation was trivial to mild in nine and moderate to severe in seven. Two patients underwent a successful Fontan-type operation. None of the 5 patients with a competent SAVV underwent valve repair or replacement; 1 of these patients died. A ventricular septal defect was closed in 14 and an extracardiac valved conduit was placed in 7. Sixteen had a regurgitant valve: it was replaced in 10 and repaired in 2 (early mortality, 25%). All 4 patients who did not undergo repair or replacement of their regurgitant SAVV died. Two patients died late after repeat replacement. Four other reoperations (closure of a residual ventricular septal defect, SAVV replacement, left ventricle-to-pulmonary artery conduit replacement, and a redo Fontan procedure) were successful. Two patients are lost to follow-up, and 9 have been followed up for from 27 to 156 months (median, 117 months). All were well when last seen. We suggest that an abnormal regurgitant SAVV should be replaced. Alternatively, a "double-switch procedure that leaves the tricuspid valve in the pulmonary circulation may be used. (Ann T~OYUC Surg 2994;57:941-5) he results from the surgical treatment of lesions asso- T ciated with atrioventricular (AV) discordance have improved in recent years [14]. Techniques for preventing injury to the conduction tissue during ventricular septal defect (VSD) closure [5-71 and for conduit placement and replacement [8, 91 have all been well described. The tricuspid valve functions as a systemic AV valve (SAVV) in these patients. It is of interest that the results of operation remain much less satisfactory in patients with either anatomically or functionally abnormal SAVVs [ 1, 41. We have reviewed our experience in 90 patients who underwent intracardiac repairs of anomalies associated with AV discordance [lo]. In that study, 20 variables were analyzed statistically, and the most significant risk factor for early death was an anatomically abnormal SAVV (p < ) (Table 1). Less than optimal results in patients with an abnormal SAVV contrasted strongly with the excellent results achieved in patients with a normal SAVV (Table 2). This report analyzes in greater detail a subgroup of 21 patients with AV discordance associated with a morphologically abnormal SAW. Material and Methods Definitions A discordant AV connection is a cardiac anomaly in which the right atrium connects to a morphologically left ventri- Accepted for publication Aug 2, Address reprint requests to Mr Stark, The Hospital for Sick Children, Great Ormond St, London WClN 3JH, England. cle and the left atrium to a morphologically right ventricle. Excluded from this study were patients with atrial isomerism and univentricular AV connection. A systemic atrioventricular valve in the setting of a discordant AV connection is a morphologically tricuspid valve that connects the pulmonary venous, morphologically left atrium to the systemic, morphologically right ventricle. In a dysplastic SAVV, the leaflets are thick and abnormal, with or without shortened chordae, when observed on cross-sectional echocardiography, or at operation or autopsy. In an Ebstein SAVV, any part of the septal or mural leaflet attachment is displaced below the AV annulus. In a straddling SAW, the tension apparatus of the valve is attached partly or completely to the morphologc left ventricle. SAW regurgitation was assessed by right ventricular angiography, and was graded as follows: 1/4 (trivial) = the dye cleared with each beat and never filled the entire left atrium; 2/4 (mild) = the entire left atrium was opacified faintly after several beats; 3/4 (moderate) = the left atrium was completely opacified and its opacification was equal to that in the right ventricle; and 4/4 (severe) = opacification of the entire left atrium occurred with one beat and became more dense with each beat; reflux of the contrast medium into the pulmonary veins was seen. Pa tien ts All patients who underwent an intracardiac repair of lesions associated with AV discordance and SAVV at the Hospital for Sick Children, Great Ormond Street and Harley Street Clinic, London, between 1975 and 1990 were included in this study. Follow-up of this group of by The Society of Thoracic Surgeons /94/$7.00

2 942 HORVATH ET AL Ann Thorac Surg Table 1. Incremental Risk Factors for Early Death in 90 Patients With AV Discordance" Risk Factors p Value Morphologically abnormal SAVV SAVV regurgitation Date of operation Pre-/perioperative complete heart block SAVV operation (repaidreplacement) 0.05 a Thirteen early deaths. AV = atrioventricular; SAVV = systemic atrioventricular valve. patients was completed in December Of the 21 patients, 16 were male and 5 were female. The mean age at intracardiac repair was 8.5 years (range, 14 months to 20 years). The ventriculoarterial connection was discordant in 17 patients and of a double-outlet right ventricle type in 4. An interventricular communication was present in 16 patients, pulmonary stenosis in 8 patients, and pulmonary atresia in none. An Ebstein malformation of the SAVV was present in 11 patients, a straddling SAW in 6 patients, and a dysplastic SAVV in 4 patients (in 1 as part of an ASD). The valve was regurgitant in 16 patients and it was competent in the remaining 5. Regurgitation was graded as trivial to mild in 9 and moderate to severe in 7 (6 with an Ebstein-type valve and 1 with a dysplastic valve). Previous palliative operation was performed in 8 patients. This consisted of pulmonary artery banding and a systemic-to-pulmonary shunt in 4 patients each. Surgical Technique A VSD was present in 16 patients. It was left open in 2 patients who underwent a Fontan-type repair; it was closed in the remaining 14 patients. Our preferred technique is to perform closure through the right atrium and mitral valve, with placement of the sutures on the morphologic right side of the septum, through the VSD [5]. This technique was used in 12 patients; in 1 of them, the mitral valve leaflet was detached to facilitate the exposure. The VSD was closed with a patch in all except 1 patient, in whom direct closure was possible. Access through the left atrium and SAW or through the left ventricle were required on one occasion each. Ventricular septa1 defect closure was technically difficult in 5 patients with a straddling SAVV, but it was possible to deviate the patch at the inferior corner of the VSD and to preserve the chordae in all patients. In patients with an Ebstein malformation, the tissue of the displaced valve made visualization of the VSD edge less clear. Obviously the VSD closure was much easier in the 6 patients who underwent SAW replacement. In addition to these 6 patients, 4 other patients with an Ebstein malformation and intact ventricular septum underwent primary SAVV replacement, for a total of 10 repla'cements. In the beginning of the series, we used xenograft valves (n = 5) but later we changed to using mechanical prostheses (n = 5) for the SAVV replacements. Currently, we prefer to use mechanical bileaflet prostheses as the valves for these patients. A standard technique of valve insertion with either interrupted pledgeted sutures or a running suture was used. In patients with an Ebstein deformity, the prosthesis was inserted at the level of the annulus after excision of the malformed valve. Two patients underwent valve reconstruction: 1 patient with a dysplastic SAVV and intact ventricular septum underwent an eccentric valve ring annuloplasty; a second patient essentially underwent repair of a complete ASD with a very dysplastic common valve. No operation was performed for the SAW in 9 patients: 5 with abnormal, competent SAVV (including 2 who underwent a Fontan operation) and 4 with abnormal, regurgitant SAVV. An external valved conduit was used to bypass the subpulmonary stenosis in 7 of the patients with this abnormality. The eighth patient underwent a Fontan operation. Earlier in the series, we used xenograft conduits (n = 5), but currently we prefer to use a cryopreserved aortic or pulmonary homograft extended with a Gore-Tex tube (W. L. Gore & Associates, Flagstaff, AZ)I in patients with AV discordance (2 patients in this series). Associated procedures included occlusion of previous shunts, reconstruction of the pulmonary artery after previous banding, and closure of an ASD. A permanent pacemaker was inserted in a patient with complete heart block, and accessory pathway ablation was done at the time of intracardiac repair in a patient with the Wolff- Parkinson-White syndrome. In 2 patients, one with a dysplastic nonregurgitant SAW and a small systemic ventricle, the other with a straddling nonregurgitant SAW, a Fontan-type repair was performed. Results Two patients underwent a Fontan-type repair, and both survived. The 19 remaining patients underwent biventric- Table 2. Mortality Associated With Intracardiac Repair in 90 Patients With AV Discordance ( ) Early Mortality Late Mortality Total Mortality SAW No. Percent 95% CL No. Percent 95% CL No. Percent 95% CL Normal (n = 69) Abnormal (n = 21) Ei6.2 Total AV = atriovenhicular; CL = confidence limits; SAVV = systemic atrioventricular valve.

3 Ann Thorac Surg HORVATH ET AL 943 ular repair; 8 died early. All 4 patients with a regurgitant valve who did not undergo repair or replacement died. One of 5 patients with an anatomically abnormal but competent valve died. Three of 12 patients who underwent repair or replacement died. The primary cause of death was cardiac (low cardiac output) in all patients, often complicated by septicemia and renal failure. One patient had good hemodynamics initially and was extubated a few hours after operation, but suffered a sudden fatal cardiac arrest during the first postoperative day. The cause of this sudden death remained unexplained. Another patient had low cardiac output associated with supraventricular tachycardia after SAW replacement and died on the second postoperative day. A third patient died in cardiac failure 2 weeks after pulmonary artery debanding, together with VSD and ASD closure. Another patient with a crisscross heart and dysplastic SAVV had clinically gross SAVV regurgitation after closure of the VSD and insertion of the left ventricle-topulmonary artery conduit. The valve was not replaced. He suffered a myocardial infarction at recatheterization 3 weeks after the operation. Two patients required early reoperation, and both died. One with a dysplastic SAW, who underwent VSD closure and insertion of a conduit from the left ventricle to the pulmonary artery, exhibited poor hemodynamics postoperatively due to persistent severe SAW regurgitation. A valve replacement was attempted 4 weeks later, but the patient died within 24 hours in low cardiac output. The second patient had an Ebstein malformation of the SAW and a VSD, with right-to-left shunting from the morphologically left ventricle to the atrialized portion of the right ventricle. He was in atrial fibrillation before the operation. The VSD patch was anchored at its superior margin to the thin fibrous tissue belonging to the displaced left AV valve. This patch attachment was disrupted twice within 2 weeks of the operation. The SAW was also grossly incompetent. At the second reoperation, commissuroplasty was attempted without success and the valve had to be replaced with a prosthesis. The postoperative period was complicated by serious arrhythmias and septicemia, and the patient died 5 days after the second reoperation. We are concerned that 2 patients were discharged from the hospital in an acceptable hemodynamic state but died shortly after returning home. Valve dehiscence was the suspected but unproven cause of death. Both are included among the early deaths. Fifteen patients survived the operation and were discharged from the hospital. Of these, there were two late deaths: 1 patient originally underwent VSD closure, left ventricle-to-pulmonary artery conduit, replacement of SAW, and ablation of the accessory pathway for the Wolff-Parkinson-White syndrome. Six years later, he required repeat replacement of the SAVV, replacement of the conduit with a homograft, and further ablation of the accessory pathway. He died in low cardiac output after this reoperation. The second late death occurred in another institution at the time of SAW repeat replacement 7 years after the original operation. Injury to the main right and left coronary arteries was considered an important contributing factor to the patient s death. Two patients from abroad were lost to follow-up. They were last seen 1 month after operation and were in a good condition at that time. Information about long-term follow-up is available in 9 patients (range, 27 to 156 months; median, 117 months). Four patients underwent successful reoperation. This consisted of reclosure of the VSD in 1 and a xenograft AV valve replacement after 4 years in another. One patient required revision of the Fontan and insertion of a pacemaker 11 years after the original operation. She was well at the last follow-up 14 months after the reoperation. One patient had a Carpentier-Edwards conduit replaced after 12 years. Two other patients with mild to moderate gradients between the left ventricle and pulmonary artery will probably require conduit replacement in the future, and a patient who underwent SAVV reconstruction may require valve replacement for the treatment of moderate residual SAVV regurgitation. This regurgitation has not increased during the 29 months of follow-up and the patient is currently well. The 9 patients with long-term follow-up are clinically well; the 5 with mechanical valves are well maintained on anticoagulant treatment. Comment The incidence of an abnormal SAVV in patients with AV discordance is high. Lundstrom and associates [2] reported an incidence of 33% and Williams and colleagues [4] cited an incidence of 37%. It was 23% in our series of 90 patients [lo]. Allwork and co-workers [ll] observed a much higher incidence of 91% in an anatomic series. Not all anatomically abnormal valves are incompetent. Graham and colleagues [12] studied 24 patients and found an incompetent SAVV in 37%. In our series of 90 patients, 69 had normal SAVVs; in 9 (13%), the valve was regurgitant before surgery. In those patients with a normal SAVV, the severity of the regurgitation was only trivial to mild. No valve required early replacement and there was no death (early or late) in this group. Only 1 patient underwent (successfully) late AV valve replacement. These findings contrast with the high incidence (71%) of SAVV incompetence in our 21 patients whose valve was considered abnormal. The mortality rate was high in all three groups with an abnormal SAW: Ebstein (6 of ll), straddling (3 of 6), and dysplastic (1 of 4). However, there was no clear relationship between the functional state of the SAVV and the outcome of the operation. Of 5 patients with an abnormal but competent SAVV, 1 died. Of 16 patients with an abnormal and incompetent valve, 9 died. The main difference seemed to be related to the surgical approach. In the 16 with an abnormal and incompetent SAW, correction of other defects without repairing or replacing the valve was the approach used in 4 patients, and they all died. The valve was either repaired (n = 2) or replaced (n = 10) in the remaining 12 patients, with an early mortality of 25% (n = 3) and total mortality of 42% (n = 5). We can extrapolate from the findings in this small and nonhomogeneous series that competence of the

4 944 HORVATH ET AL Ann Thorac Surg SAVV is important for survival. It is important to realize that even a minor degree of SAVV regurgitation can be exacerbated by ventricular dysfunction, seen often after cardiopulmonary bypass [2]. Based on the data presented, we believe that an aggressive approach to the incompetent SAW is justified. If valve competence cannot be achieved by reconstruction, then the valve should be replaced. If valve competence is considered adequate after termination of cardiopulmonary bypass but deteriorates during the first 24 postoperative hours, early valve replacement should be seriously considered. It is quite clear from the data presented that long delays in making this decision only lead to low cardiac output, deterioration of ventricular function, deterioration of renal function, and ultimately death of the patient. Incompetence of SAVV causes symptoms before the age of 2 years in only a few patients [2]. Our experience with valve repair in small children is limited to 2 patients. In 1, the repair was part of repair of a complete AV septal defect, and was observed to have produced good results up to 139 months after the operation. The second patient was 14 months old, and is currently well with moderate AV valve regurgitation 29 months after surgery. Williams and associates [4] reported good results from repair of SAVVs, although the rate of reoperation in their series was high (50%). Currently we prefer to delay operation in asymptomatic or mildly symptomatic infants with AV discordance and SAVV incompetence. In severely symptomatic patients, we attempt reconstruction but accept only trivial residual regurgitation. With the availability of small mechanical prostheses such as the 16-mm Carbomedics valve (Carbomedics, Austin, TX), such valve replacement is now possible even in neonates. Alternatively, one can use the recently suggested techniques which leave the tricuspid valve as a subpulmonary rather than systemic valve. In the "double-switch" operation, a Mustard or Senning procedure is combined with the arterial switch operation [ 131. Brawn and associates [14] reported on 2 patients in whom severe tricuspid valve incompetence become insignificant after this procedure. However, as subpulmonary obstruction is often present in patients with AV discordance, an alternative doubleswitch method may be used. It involves the combination of a Mustard or Senning procedure with a Rastelli-type operation (redirection of left ventricular output through the VSD to the aorta and placement of a valved conduit from the right ventricle to the pulmonary artery) [15]. We have used this approach in 1 patient with excellent results. A straddling SAVV poses different problems. Accurate diagnosis is very important. Although it is possible to evaluate the valve by catheterization and angiocardiography [ 161, two-dimensional echocardiography is superior for this purpose [17, 181, particularly in combination with color-flow Doppler imaging. Transesophageal echocardiography is very useful in older patients, while epicardial echocardiography can help to evaluate the result of valve repair intraoperatively. A straddling AV valve may be associated with hypoplasia of one of the ventricular chambers [3, 191. Under such circumstances, biventricular repair may not be possible. If the pulmonary arteriolar resistance is low and the SAVV competent, a Fontan-type repair may be the better or only option. If the SAVV is regurgitant, it may be possible to either close it or repair or replace it at the time of the Fontan-type repair. If the straddling of the SAVV is only to the crest of the septum, it may be possible to place the VSD patch with a slit to accommodate the straddling chordae. One should, however, remember that, in the presence of straddling, the conduction system may be situated abnormally [:20]. The technique described by Ilbawi and colleagues [7] rnay be useful in this situation. Straddling of the right AV valve is exceedingly rare [21]. The results from the surgical treatment of lesions associated with AV discordance have improved in recent years [l, 21. In our own experience, the total mortality rate (early and late) was 7.7% in the 39 patients operated on during 1985 to 1990, compared to 27.5% in the 51 patients operated on during 1975 to Similar improvement can be seen in the subgroup of patients with an abnorimal SAW. Seven of 9 (78%) died during 1975 to 1981, wlhile 3 of 21 (25%) died during 1981 to Despite these improvements, repair of the lesions asjsociated with AV discordance remains a major challenge. The new techniques such as a double-switch operation, involving a Mustard or Senning operation together with an arterial switch operation [13] or Rastelli operation [ 151, may lead to further improvements in the results. For some patients, however, heart transplantation may be the only option. References 1. McGrath LB, Kirklin JW, Blackstone EH, Pacifico AD, Kirklin JW, Bargeron LM. Death and other events after cardiac repair in discordant atrioventricular connection. J Thorac Cardiovasc Surg 1985;90: Lundstrom U, Bull C, Wyse RKH, Somerville J. The natural history and "unnatural" history of congenitally corrected transposition. Am J Cardiol 1990;65: Hwang B, Bowman F, Malm J, Krongrad E. Surgical repair of congenitally corrected transposition of the great arteries: results and follow-up. Am J Cardiol 1982;50: Williams WG, Suri R, Shindo G, Freedom RM, Morch JE, Trusler GA. Repair of major intracardiac anomalies associated with atrioventricular discordance. Ann Thorac Surg 1990;31: De Leval MR, Bastos P, Stark J, Taylor JFN, Macartney FJ, Anderson RH. Surgical technique to reduce the risks of heart block following closure of ventricular septal defect in atrioventricular discordance. J Thorac Cardiovasc Surg 1979;78: Doty DB, Truesdell SC, Marvin WJ. Techniques to avoid injury of the conduction tissue during the surgical treatment of corrected transposition. Circulation 1983;68(Suppl2): Ilbawi MN, DeLeon SY, Backer CL, et al. An alternative approach to the surgical management of physiologically corrected transposition with ventricular septal defect and pulmonary stenosis or atresia. J Thorac Cardiovasc Surg 1990;100: De Leval MR. Reoperations for atrioventricular discordance. In: Stark J, Pacifico AD, eds. Reoperations in cardiac surgery. Berlin, Heidelberg: Springer-Verlag, 1989: Hopkins RA. Anterior ventricle to pulmonary artery allograft conduit in corrected transposition. In: Hopkins RA, ed.

5 Ann Thorac Surg HORVATH ET AL 945 Cardiac reconstructions with allograft valves. New York: Springer-Verlag, 1989:16% Szufladowicz M, Horvath P, Bull C, et al. Intracardiac repair of lesions associated with atrioventricular discordance. Eur J Cardiothorac Surg (in press). 11. Allwork SP, Bentall HH, Becker AE, et al. Congenitally corrected transposition of the great arteries: morphologic study of 34 cases. Am J Cardiol 1976;38: Graham TP, Parrish MD, Boucek RJ, et al. Assessment of ventricular size and function in congenitally corrected transposition of the great arteries. Am J Cardiol 1983;51:24& Yagihara T, Yamamoto F, Fujita T, et al. Anatomical correction of cardiac anomalies associated with atrioventricular discordance (abstract 632). Presented at the 3rd World Congress of Paediatric Cardiology, Bangkok, Thailand, Nov 26 to Dec Brawn WJ, Wright JG, Sethia 8, de Giovanni J, Silove ED. Atrial and arterial switch repair for corrected transposition and ventricular septa1 defect with severe tricuspid valve regurgitation. Cardiol Young 1993;3(Suppl): Imai Y, Sawatari K, Hoshino S, Ishihara, Nakazawa M, Momma K. Ventricular function after anatomical repair in patients with atrioventricular discordance. Presented at the 73rd Annual Meeting of the American Association for Thoracic Surgery, Chicago, IL, Apr 28, Pacific0 AD, Soto B, Bargeron LM. Surgical treatment of straddling tricuspid valves. Circulation 1979;60: Celermajer DS, Cullen S, Deanfield JE, Sullivan ID. Congenitally corrected transposition and Ebstein's anomaly of the systemic atrioventricular valve: association with aortic arch obstruction. J Am Coll Cardiol 1991;18:105fX. 18. Hagler DJ, Tajik AJ, Seward JB, Edwards WD, Mair DD, fitter DG. Atrioventricular and ventriculoarterial discordance (corrected transposition of the great arteries): wideangle two-dimensional echocardiographic assessment of ventricular morphology. Mayo Clin Proc 1981;56: Erath HG, Graham TI', Hammon JW, Smith CW. Hypoplasia of the systemic ventricle in congenitally corrected transposition of the great arteries. J Thorac Cardiovasc Surg 1980;79: Kurosawa H, Imai Y, Becker AE. Congenitally corrected transposition with normally positioned atria, straddling mitral valve, and isolated posterior atrioventricular node and bundle. J Thorac Cardiovasc Surg 1990;99: Becker AE, Ho SY, Caruso G, Milo S, Anderson RH. Straddling right atrioventricular valves in atrioventricular discordance. Circulation 1980;61: