Revision of Previous Fontan Connections to Extracardiac or Intraatrial Conduit Cavopulmonary Anastomosis

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1 Revision of Previous Fontan Connections to Extracardiac or Intraatrial Conduit Cavopulmonary Anastomosis Doff B. McElhinney, MS, V. Mohan Reddy, MD, Phillip Moore, MD, and Frank L. Hanley, MD Divisions of Cardiothoracic Surgery and Pediatric Cardiology, University of California, San Francisco, San Francisco, California Background. In patients who have received an atriopulmonary Fontan connection, complications such as right pulmonary vein obstruction, atrial arrhythmias, and thromboembolism are often secondary to right atrial enlargement. When such complications develop despite good ventricular function, there are few management options available. Extracardiac or intraatrial conduit cavopulmonary anastomosis, which improves central systemic venous flow patterns, avoids atrial distention, and does not involve the extensive atrial suturing required by other forms of cavopulmonary anastomosis, may provide relief for this group of patients. Methods. Between October 1992 and October 1995, 7 patients presented 8 to 20 years after atriopulmonary connection with severe right atrial dilatation (7), Fontan pathway obstruction (4), progressive congestive heart failure (4), atrial tachydysrhythmias (3), right atrial thrombus (1), obstruction of right pulmonary veins by an enlarged right atrium (1), and subaortic stenosis (1). After evaluation of the options, they underwent revision of the atriopulmonary connection to extracardiac (5) or intraatrial (2) conduit cavopulmonary anastomosis. Results. One patient with severe cachexia, in whom transplantation was contraindicated for social reasons, died in the early postoperative period of massive effusions. Two patients eventually required permanent pacing for atrial dysrhythmias (1) or complete heart block secondary to subaortic fibromuscular resection (1), and 2 demonstrated marked improvement in unstable preoperative rhythm disturbances. At a median follow-up of 17 months, 4 of the 6 survivors were functioning at higher New York Heart Association levels than preoperatively, and 1 had recently undergone heart transplantation. Conclusions. In properly selected patients with atrial complications, revision of a prior Fontan connection to extracardiac or intraatrial conduit cavopulmonary anastomosis appears to be a viable option. (Ann Thorac Surg 1996;62: ) S ince Fontan and Baudet [1] described their technique for correction of tricuspid atresia in 1971, the Fontan or modified Fontan physiology has become a favored reparative end point for nearly all forms of functional single ventricle. Though early and late survival rates have been improving over time, patients undergoing any of the various modifications of the Fontan operation are still subject to substantial postoperative morbidity and mortality [2, 3]. In many cases, sequelae appear to be related at least in part to the incorporation of the right atrium (RA) into the Fontan circuit: namely, RA dilatation, right pulmonary vein obstruction, thromboembolism, and supraventricular dysrhythmias [2-6]. Obstruction at the atriopulmonary connection and hepatic failure also can occur. It is thought that the modification introduced by de Leval and associates [7], according to which caval blood is routed into the pulmonary artery (PA) without incorporating the RA, will alleviate some of these Presented at the Thirty-second Annual Meeting of The Society of Thoracic Surgeons, Orlando, FL, Jan 29-31, Address reprint requests to Dr Reddy, 505 Parnassus Ave, M593, San Francisco, CA common complications by reducing the turbulence of central venous flow [8, 9]. When patients with atriopulmonary Fontan connections decline in functional status, the cause must be determined. Irreversible ventricular systolic dysfunction with or without diastolic dysfunction and elevated pulmonary vascular resistance cannot be reversed without transplantation. However, other causes can, at least in theory, be reversed with operative revision. Because these patients often have complex conditions and are physiologically fragile, with chronic effusions and cachexia, the physiologic efficacy of revision is unproven, as is the ability of these patients to tolerate the procedure acutely without excessive morbidity and mortality. To complicate the issue further, ventricular dysfunction may be related to elevated coronary sinus pressure [10], which can be secondary to Fontan obstruction or right pulmonary venous obstruction, and as a result there may be a component of reversibility in such circumstances. In this report, we present our experience with patients who underwent revision of their atriopulmonary-type Fontan connection to either extracardiac or intraatrial conduit cavopulmonary anastomosis and discuss the 1996 by The Society of Thoracic Surgeons /96/$15.00 Published by Elsevier Science Inc Pll S (96)00567-X

2 Ann Thorac Surg McELHINNEY ET AL ;62: FONTAN REVISION Table 1. Patient Characteristics at Fontan Revision Years After Patient Age Original No. Diagnosis (y) Fontan 1 {S,L,L}, DILV, severe PS {S,D,S}, unbalanced CAVC {S,D,S}, pulmona D, atresia, IVS 4 {S,L,L}, DILV, PS, LPA hypoplasia, rbvf 5 {S,D,S}, TA, PS, PA hypoplasia {S,D,S}, TA, severe PS {S,D,D}, TA, juxtaposed RA appendages No. of Previous Previous Original Fontan Fontan Operations Type Revision 2 Direct RA-PA No anastomosis 6 RA-PA conduit No 2 RA-PA conduit No 2 RA-PA conduit Yes, 9.2 y previously 2 RA-RV No anastomosis 3 RA-PA conduit Yes, 10 y previously 2 RA-PA conduit No CAVC complete atrioventricular canal; D1LV double inlet left ventricle; Ivs ~ intact ventricular septum; LPA - left pulmonary artery; PA = pulmonary, artery; PS pulmonary stenosis; RA = right atrium; rbvf = restrictive bulboventricular foramen; RV - right ventricle; {S,D,D}, {S,D,S},{S,L,L}- segmental situs Ill]; TA - tricuspid atresia. indications for and implications of revising atriopulmonary to total cavopulmonary connection. Patients and Methods Patients Seven patients, ranging in age from 10.3 to 28.8 years, presented 8.5 to 20.5 years (median, 11.4 years) after a modified Fontan operation (Table 1) [11]. Originally, these patients had undergone either placement of valved RA to PA conduits (n = 5), direct RA-PA anastomosis (n = 1), or anastomosis of the right atrial appendage to the right ventricle (RA-RV; n = 1). All patients had done well after their original Fontan procedure except for patient 2 (see later). Of the 5 patients with RA-PA conduits, 2 (patients 4 and 6) had their valved conduits replaced with valveless synthetic tubes 9.2 and 10.0 years before revision, and 1 (patient 2) had a conduit placed between his left and right PAs 9.4 years before revision. Preoperative status of the patients and indications for revision are summarized in Table 2; hemodynamic and oximetric data are presented in Table 3. Patient 1 presented with massive RA dilatation, mild tricuspid and aortic regurgitation, and decreasing exercise tolerance. Ventricular end-diastolic pressure (VEDP) was elevated to 10 mm Hg, and pulmonary vascular resistance was 5.9 Wood units. An electrophysiologic study revealed two types of atrial flutter plus atrioventricular nodal reentrant tachycardia. Fontan revision was deemed the best option. Patient 2 presented with extreme Fontan failure. He had never done well after his original Fontan operation, having undergone early implantation of a permanent bipolar epicardial pacemaker and experiencing progressive congestive heart failure. Seven years after atriopulmonary anastomosis, he experienced a pulmonary embolic event, and several months before revision, his failure began to increase in severity, with progressive ascites, worsening inguinal hernias, bilateral effusions, proteinlosing enteropathy, and hepatic dysfunction. In addition, a massive thrombus filled most of his RA and extended into his conduits. However, there was no obstruction; his RA and PA pressures were equal because of extensive collaterals draining into the coronary sinus. A preferable therapeutic option would have been orthotopic heart transplantation, but social factors precluded this, so Fontan revision was offered as a last resort after drainage of his ascites. Patient 3 presented in New York Heart Association class II. Routine echocardiography had shown a huge RA, with poor forward flow and a question of mural thrombus. Fontan obstruction was also present with a gradient of 3 mm Hg. Preoperative evaluation had also demonstrated a reasonably sized RV, as well as potentially functional valve leaflets beneath the tricuspid patch that had been a component of his original Fontan procedure. On the basis of his RA dilatation and the possibility of mural thrombus, operative reintervention was recommended. There was some hope that his right-sided anatomy would be suitable for one-and-a-half ventricle repair. Intraoperatively, however, it was determined that such a solution would probably not work well, and Fontan revision to extracardiac cavopulmonary anastomosis was completed. Patient 4 demonstrated bulboventricular foramen obstruction with a peak systolic gradient of 40 mm Hg, and was asymptomatic and without appreciable Fontanrelated compromise. However, her RA was markedly dilated, with a 3 mm Hg RA to PA gradient. Because subaortic resection was necessary and Fontan pathway obstruction was present, we decided it would be logical to revise her Fontan at the same time to preempt the development of atrial dysrhythmias or the potential need for later Fontan-related reinterventions.

3 1278 McELHINNEY ET AL Ann Thorac Surg FONTAN REVISION 1996;62: Table 2. Indications for Fontan Revision and Preoperative Status Patient NYHA Ventricular RA RA No. Class Indication for Revision Rhythm Function Dilatation Thrombus AVVR 1 II Atrial tachydysrhythmias secondary to AFlut, AFib, AV Mildly Severe No Mild RA dilatation. Elevated PVR. No nodal reentry depressed obstruction. IV Increasing, severe CHF, thrombus CHB-PPM Severely Severe Yes No completely filling RA and conduit depressed with all flow to PAs through CS and LSVC. No obstruction (by pressure gradient). II Conduit valve stenosis with poor 1 AV block, Normal Severe Maybe/no ~ No forward flow, RA enlargement and intermittent possible RA thrombus 2 AV block I Moderate subas (40 mm Hg) due to NSR Normal Severe No No BVF membrane, RA enlargement III Severe conduit obstruction with NSR Normal Severe No Mild increasing DOE, s/p unsuccessful PTBD III RA-PA conduit obstruction and branch 1 AV block, Normal Severe No Mild PA hypoplasia, with RA enlargement, recent atrial worsening CHF, and frequent atrial tachydysrhythmias tachydysrhythmias requiring cardioversion 7 III RPV obstruction by enlarged RA, Atrial Normal Severe Maybe/no a Mild increasing CHF, possible RA thrombus, atrial dysrhythmias tachydysrhythmias, PPM for sinus bradycardia '~ By preoperative echocardiogram, it appeared as though right atrial thrombus may have been present; at operation, no thrombus was found. AFib - atrial fibrillation; AFlut atrial flutter; AV atrioventricular; AVVR atrioventricular valve regurgitation; BVF - bulboventricular foramen; CHB complete heart block; CHF - congestive heart failure; CS - coronary sinus; DOE - dyspnea on exertion; LSVC ~ left superior vena cava; NSR - normal sinus rhythm; NYHA New York Heart Association; PA - pulmonary artery; PPM = permanent pacemaker; PTBD percutaneous transluminal balloon dilatation; PVR = pulmonary vascular resistance; RA = right atrium; RPV right pulmonary vein; subas - subaortic stenosis. Patient 5 presented with pronounced obstruction of her RA-RV anastomosis (RA-PA gradient, 11 mm Hg) and declining functional status. Her RA was severely enlarged, but she had no rhythm disturbances or evidence of thrombus. Preoperatively, catheter balloon dilatation of her stenotic RA-RV anastomosis was unsuc- cessful and it was decided that conversion to extracardiac conduit total cavopulmonary anastomosis was preferable to simple revision of the conduit obstruction. Patient 6 was in progressive heart failure and had recently developed unstable atrial arrhythmias that were unresponsive to flecainide and required electrical cardioversion. Her systolic cardiac function was adequate, but the VEDP was elevated to 13 mm Hg and there was mild Table 3. Prerevision '~ and Postrevision ~' Hemodynamic Indices and Oxygenation Status Patient Prerevision Postrevision No. SaO 2 PO 2 RAP e PAP VEDP PVR SaO 2 PO 2 PAP VEDP Mean SD Prerevision values were recorded at the time of cardiac catheterization 31 to 110 days preoperatively (mean, 64 days) with all patients breathing room air. b Postrevision data reflect values on the first postoperative day, at which point all patients except for patient 2 had been extubated, c Right atrial pressure (RAP) is presented to demonstrate conduit obstruction (ie, the difference between right atrial pressure and pulmonary artery pressure). PAP = pulmonary, artery pressure; PO 2 arterial partial pressure of oxygen (in mm Hg); PVR pulmonary, vascular resistance; SaO 2 - percent arterial oxygen saturation of hemoglobin; SD standard deviation; VEDP = ventricular end-diastolic pressure (in mm Hg).

4 Ann Thorac Surg McELHINNEY ET AL ;62: FONTAN REVISION mitral valve insufficiency. Her RA was extremely dilated, with a 6 mm Hg gradient across her proximal right PA. We elected to revise her Fontan and reconstruct her stenotic PA. Patient 7 presented with a severely dilated RA that was extending posteriorly and compressing both the upper and lower right pulmonary veins. This probably contributed to the calculated elevation in her pulmonary vascular resistance to 4.7 Wood units. Her inferior vena cava was also markedly dilated, and echocardiography results suggested a thrombus in the RA. She had previously had a permanent pacemaker placed for sinus bradycardia, but she also experienced atrial tachydysrhythmias. Her cardiac output was poor despite borderline normal ventricular function, and she had very low exercise tolerance, marked ascites, and mild mitral regurgitation. Revision to extracardiac conduit Fontan was elected. Operative Procedure Because of adhesions from multiple previous operations, the dissection can be difficult and often tedious in these patients. In 1 patient, it was necessary to initiate cardiopulmonary bypass through femorofemoral cannulation, though in the remaining patients we were able to dissect completely the aorta and both cavae and begin bypass using standard aortic and caval cannulation. In patients who are particularly fragile, it may be wise to expose the groin vessels before attempting to dissect the mediastinum, so that femorofemoral bypass can be initiated if necessary. Because the morphology of the patients' lesions and their surgically altered anatomy differed considerably, there was some variation in the technique of Fontan revision and additional procedures performed. All patients had their previous atriopulmonary or modified atriopulmonary connections taken down and replaced with extracardiac or intraatrial conduit total cavopulmonary anastomoses. In 5 patients (patients 2, 3, 5, 6, and 7), extracardiac conduit total cavopulmonary anastomosis was performed [12]. A bidirectional superior cavopulmonary shunt was performed, with transection of the superior vena cava, oversewing of the cardiac stump, and end to side anastomosis of the cranial end to the right PA. The inferior vena cava was transected at its junction with the RA, and the cardiac end was oversewn. The inferior vena cava was anastomosed to an expanded polytetrafluoroethylene conduit (range, 20 to 25 mm in diameter), which was connected end-to-side with the underside of the right PA, completing the extracardiac conduit Fontan. Reduction of the RA was performed in 4 of these patients (patients 2, 3, 5, and 7), as was atrial septectomy (patients 2, 3, 6, and 7). Reconstruction of the PA was carried out in 3 of these patients (patients 2, 6, and 7), and 1 patient (patient 2) underwent RA thrombectorny, left superior vena cava ligation, and pacemaker replacement. None of these patients had right to left atrial level "pop-off" shunts included. Extracardiac conduit revision was our preferred policy. In 2 patients (patients 1 and 4), however, after the appropriate structures were dissected, it was determined that RA dimensions and mobility were not amenable to the creation of a suitable channel for the extracardiac conduit, and intraatrial conduit Fontan was performed instead. Superior cavopulmonary anastomosis was performed in the same manner as with extracardiac cavopulmonary anastomosis. Through a right atriotomy, a valveless 22-ram expanded polytetrafluoroethylene tube was sewn to the inferior cavoatrial junction, carried up through the RA appendage, and anastomosed at the point of previous atriopulmonary connection. In patient 4, the cavopulmonary anastomoses were not directly end to side, but slightly anterior, with an expanded polytetrafluoroethylene hood carried over the anterior aspect of the connection to enlarge the junction. Both of these patients had 5-mm conduit fenestrations placed, 1 (patient 1) because of a high preoperative Fontan pressure and transpulmonary gradient, and the other (patient 4, in whom ventricular muscle resection was performed to enlarge the bulboventricular foramen) because of concerns about early postoperative rhythm disturbances and ventricular dysfunction. In addition, atrial septectomy was performed in both of these patients, and RA reduction was done in patient 1. In patient 4, the bulboventricular foramen was enlarged in accordance with the known location of the conduction axis, with resection of a wedge of tissue from the apical trabecular septum by incising close to the obtuse margin of the ventricular mass. Total perfusion time ranged from 82 to 320 minutes (mean, 228 minutes). In addition, 4 patients required aortic cross-clamping (mean, 87.7 minutes; range, 61 to 132 minutes) and cold crystalloid cardioplegia administration. All patients were maintained on coumadin for at least 3 months postoperatively. Results Operative and Early Postoperative Outcome There were no operative complications. Postoperatively, patient 2 (who had severe effusions, protein-losing enteropathy, and congestive heart failure preoperatively) experienced massive effusions with increasing acidosis. On the fourth postoperative day, he was returned to the operating room, where, in a salvage attempt, his Fontan was taken down to a bidirectional cavopulmonary shunt with additional pulmonary blood flow provided through a modified Blalock-Taussig shunt. His hemodynamic status continued to decline, and shortly after reoperation he had a cardiac arrest and could not be resuscitated. There were no other early deaths. All 6 of the remaining patients required postoperative mechanical ventilation (median, 10 hours; range, 7 to 17 hours) and inotropic support (median, 2 days; range, I to 4 days). They were discharged from the hospital at a median of 21 days after operation (range, 6 to 23 days). In 2 survivors (patients 3 and 6), effusions developed that required chest tube drainage for 12 and 21 days, respectively. In patient 3, who had no preoperative rhythm disturbances, early atrial flutter/fibrillation developed.

5 1280 McELHINNEY ET AL Ann Thorac Surg FONTAN REVISION 1996;62: Table 4. Follow-up Status Follow-up Patient No. Duration (too) NYHA Class Rhythm Rhythm Medications PPM Ventricular Function AVVR Late Reoperations 1 24 I NSR with Yes No Norma No Fontan intermittent atrial fenestration tachydysrhythmias closed 19 mo postrevision 2 Early death 3 18 IV a Recent recurrent Yes Yes Severely Mild- AFlut depressed moderate 4 17 I AFlut, AFib Yes Yes Mildly No depressed 5 23 I Episodic Yes No Normal Mild No paroxysmal atrial tachycardia, 1 AV block 6 10 I1 AFib Yes No NA NA No 7 3 I PPM No Yes Normal No No " Patient 3 recently underwent heart transplantation at another institution. Unipolar ventricular pacemaker implanted 8 mo postrevision No AFib = atrial fibrillation; AFlut -- atrial flutter; AV - atrioventricular; AVVR - atrioventricular valve regurgitation; NA not available; NSR normal sinus rhythm; NYHA New York Heart Association; PPM = permanent pacemaker; SR sinus rhythm. Patient 4 suffered complete heart block as a result of bulboventricular foramen resection. Two patients underwent early reoperation: patient 2, as discussed earlier, and patient 4, who had a permanent dual-chambered epicardial pacemaker placed on postoperative day 8, along with debridement of her thumb secondary to extravasation during transfusion and subsequent cellulitis. None of the patients demonstrated RA thrombi by echocardiographic analysis or suffered clinically evident thromboembolic events. In Table 3, variables relating to postoperative hemodynamic and oxygenation status are presented, along with comparable preoperative values. Mean systemic arterial partial pressure of oxygen increased for the group as a whole. However, in 2 patients with fenestrations in the conduit, the postrevision systemic arterial partial pressure of oxygen was lower. For both PA pressure (PAP) and VEDP, there was a clear division between patients with higher preoperative pressures (n 3; ranges: PAP, 19 to 22 mm Hg; VEDP, 10 to 13 mm Hg) and lower preoperative pressures (n - 4; ranges: PAP, 5 to 9 mm Hg; VEDP, 2 to 5 mm Hg). Pressures in the former group were lower after revision. All patients with low prerevision PAP had some degree of Fontan pathway obstruction with RA-PA gradient. Once this obstruction was relieved, the postrevision PAP increased in these patients. Follow-up Follow-up was obtained at a median of 17 months postoperatively (range, 3 to 24 months) for the 6 hospital survivors. Selected follow-up data are presented in Table 4. There had been no late deaths at the time of follow-up. Two patients had undergone late reoperation: Patient 1 had her Fontan fenestration closed 19 months after revision, and patient 3 had a permanent unipolar ventricular epicardial pacemaker placed 8 months postoperatively and underwent heart transplantation 18 months after Fontan revision. Relative to their prerevision New York Heart Association classification status, 4 patients had improved, 1 was unchanged, and 1 had deteriorated (Fig 1). All 6 patients were taking cardiac medications. Four patients, including the 2 with intraatrial conduits (patients 1 and 4), were taking coumadin as part of their medical regimen. Five patients were taking antiarrhythmia drugs, 3 of whom (patients 3, 4, 5) had had no preoperative rhythm disturbances. Two patients (patients 1 and 6) with prerevision arrhythmias were improved or stabilized in this respect at the time of followup. All surviving patients had discharge echocardiograms performed, and 5 patients had had recent follow-up echocardiograms performed, 3 to 23 months (median, 19 months) after revision. Of these, 1 patient (patient 1) demonstrated an improvement in ventricular function relative to her prerevision state, along with a decrease in tricuspid valve regurgitation from mild to none, whereas 2 patients (patients 5 and 7) with normal preoperative ventricular function were unchanged in that respect after revision. Patient 4 experienced a decline in ventricular function from normal to mildly depressed after suffering complete heart block following bulboventricular foramen enlargement. Patient 3, who had normal preoperative

6 Ann Thorac Surg McELHINNEY ET AL ;62: FONTAN REVISION Pre-Revision NYHA Class n=l ~-i~~i~ Post-Revision NYHA Class ~ ~-~ n=4 n=2 n=l n=l ~ n=l Death n=l Fig 1. New York Heart Association (NYHA) functional status classij~'cation before and after Fontan revision to extracardiac or intraatrial conduit total cavopulmona~ anastomosis in each of 7 patients. ventricular function, remained stable, with fair to normal cardiac function, for almost a year after revision to total cavopulmonary connection. However, he had progressive deterioration by 17 months after revision and development of a severely dilated ventricle with an ejection fraction of At the most recent follow-up, 18 months postoperatively, he was 2 weeks out from a successful cardiac transplantation. Only 1 patient has undergone cardiac catheterization since the Fontan revision. Comment There are limited management options for Fontan patients with deteriorating functional status. Conservative medical therapy may be sufficient if the patient is reasonably functional and if it is unlikely that operative revision will reverse the patient's status. Often, however, atrial arrhythmias in patients with atriopulmonary connection prove refractory to medical and even electrophysiologic intervention [13]. As several investigators have reported, orthotopic heart transplantation is feasible and practical in selected Fontan patients with endstage disease [14, 15]. A third option in selected Fontan patients with deteriorating functional status is revision to a total cavopulmonary anastomosis [16]. Specific indications for this approach are not clearly defined; however, patients in whom a specific complication or condition is directly addressed by the procedure are the most obvious candidates. Examples include a giant atrium with thrombus, arrhythmias refractory to medical or electrophysiologic treatment, or pulmonary venous obstruction, and possibly patients with ventricular dysfunction secondary to elevated coronary sinus pressure. Other conditions, such as obstruction of the atriopulmonary connection, restrictive bulboventricular foramen, atrioventricular valve re- gurgitation, and others can be treated operatively, but do not per se require conversion to a cavopulmonary connection. Such patients may benefit from the improved hemodynamic status of the cavopulmonary connection performed at the time of the operation for the specific lesion. We have performed a cavopulmonary conversion on patients in both of these general categories: Patients 1, 6, and 7 had conditions that could best be addressed by revision of the Fontan connection to total cavopulmonary anastomosis; in patients 3, 4, and 5, cavopulmonary revision was performed as a supplementary procedure. The most questionable indication for revision involves the patient with deteriorating functional status who has no specific target conditions; for example, the patient who is functionally very limited and has moderately elevated pulmonary vascular resistance, moderately depressed ventricular function, a large RA without specific complications, and no obstructive lesions. The improvement gained by conversion to a cavopulmonary connection might well be outweighed by the risks of the procedure itself. In our series, patient 2 fell into this category, and he represented the only death among our 7 patients. In patients 3, 4, and 5, Fontan revision was performed as a supplementary procedure. Complications arose in 2 of these patients after revision. Patient 4 required early implantation of a permanent pacemaker for complete heart block and is also taking rhythm medications. However, these complications resulted not from Fontan revision per se, but from bulboventricular foramen enlargement. Though the location of the atrioventricular conduction bundle in {S,L,L} hearts is well understood, it is sometimes difficult to avoid injury to the conduction system in these circumstances. The bundle is intrinsically fragile in {S,L,L} hearts, a fact that can be compounded by the need to resect a large wedge of tissue in more severely obstructed cases and by the considerable manipulation required to expose the bulboventricular foramen through the hypoplastic chamber. Otherwise, the functional status of patient 4 was unchanged from the preoperative status. It should be noted that she probably would not have undergone revision to cavopulmonary anastomosis at the time she did had it not been for her subaortic stenosis. Patient 3 continued to have arrhythmias that required medication and eventually permanent pacing, and deteriorated from New York Heart Association class II preoperatively to class IV at a follow-up of 17 months. One month later (18 months after Fontan revision), he underwent successful cardiac transplantation. He, along with 3 of the other patients, underwent extensive RA resection at the time of revision. This may have influenced the development of postoperative atrial flutter, although the 1 other patient who had RA resection but no preoperative atrial dysrhythmias remained in normal sinus rhythm perioperatively and at follow-up. Patient 5 had severe Fontan conduit obstruction. Although in theory a simple conduit change could have been performed, we elected to revise her Fontan. This patient had a good functional result, but paroxysmal atrial tachycardia developed after operation. This was

7 1282 McELHINNEY ET AL Ann Thorac Surg FONTAN REVIS1ON 1996;62: controlled with antiarrhythmia medication, and there has been no recurrence. The indications for revision in the remaining 3 patients-patients 1, 6, and 7--were clear: worsening or unstable arrhythmias with or without conduit obstruction with RA dilatation and increasing systemic congestion, along with PA hypoplasia in I patient and compression of the right pulmonary veins by the enlarged RA in another. Postoperatively and at follow-up, they were all markedly improved. Functional status improved in patients i and 6, along with improvement or stabilization of their atrial arrhythmias postoperatively. In terms of functional status, patient 7 improved two New York Heart Association classes and was relieved of the preoperative right-sided congestion and pulmonary venous obstruction. This patient was on a permanent pacemaker preoperatively, and no new rhythm disturbances have been noted since the operation. For a number of years, it has been theorized that elevated coronary sinus pressure in the atriopulmonary Fontan might contribute to myocardial dysfunction by reducing coronary perfusion pressure, and data from recent studies support this hypothesis [10]. In all 3 patients in our series with elevated RA pressure (and therefore coronary sinus pressure), the VEDP was elevated. In all of these cases, the VEDP was significantly reduced after conversion to the cavopulmonary anastomosis, suggesting that lowering coronary sinus pressure does in fact improve ventricular function. There is evidence that total cavopulmonary anastomosis, insofar as it takes a substantial load off the RA and improves right-sided flow patterns, may improve survival, with a decreased incidence of arrhythmias relative to Fontan modifications that incorporate the RA [8, 9]. From a technical standpoint, we prefer to perform an extracardiac conduit cavopulmonary anastomosis. Like other forms of total cavopulmonary connection, the extracardiac Fontan provides a maximally streamlined cavopulmonary communication, but requires substantially less atrial suturing and avoids trauma to the sinoatrial node region. Although the impact of total cavopulmonary connection on thromboembolic events or hepatic dysfunction is not yet certain [5, 6], it is likely to reduce rhythm disturbance, which is generally thought to be a more common and more serious source of morbidity. Of course, revising a previously placed atriopulmonary Fontan cannot be expected to yield the same results as constructing a cavopulmonary anastomosis primarily or after staged palliation. Nevertheless, relieving central venous obstruction and RA dilatation is a reasonable therapeutic maneuver from the point of view of both hemodynamic management and the prevention or alleviation of atriopulmonary Fontan-related sequelae. Fontan revision to extracardiac or intraatrial conduit total cavopulmonary anastomosis can be performed with success, and sometimes with dramatic improvement, in properly selected patients with complications referable to RA-PA or modified RA-PA connection, such as throm- bosis, pulmonary venous obstruction, or arrhythmias. Revision may also be beneficial in patients with no complications directly related to the RA-PA connection but with other indications for operation. However, it is not clear at present whether RA reduction is necessary with Fontan revision, especially in patients who have no preoperative arrhythmias. Finally, in the failing patient who both lacks complications specifically related to the RA-PA connection and has other specific indications for operation (eg, bulboventricular foramen obstruction, atrioventricular valve regurgitation), revision to total cavopulmonary anastomosis may be ill advised. At present, such patients with severe exercise intolerance, effusions or ascites, and protein-losing enteropathy are not considered candidates for revision. References 1. Fontan F, Baudet E. Surgical repair of tricuspid atresia. Thorax 1971;26: Driscoll DJ, Offord KP, Feldt RH, et al Five- to fifteen-year follow-up after Fontan operation. Circulation 1992;85: Fontan F, Kirklin JW, Fernandez G, et al. Outcome after a "perfect" Fontan operation. Circulation 1990;81: Gewillig M, Wyse RK, de Leval MR, Deanfield JE. Early and late arrhythmias after the Fontan operation: predisposing factors and clinical consequences. Br Heart J 1992;67: Cromme-Dijkuis AG, Hess J, Hahlen K, et al. Specific sequelae after Fontan operation at mid- and long-term followup. J Thorac Cardiovasc Surg 1993;106: Jahangiri M, Ross DB, Redington AN, et al. Thromboembolism after the Fontan procedure and its modifications. Ann Thorac Surg 1994;58: De Leval MR, Kilner P, Gewillig M, Bull C. Total cavopulmonary connection: a logical alternative to atriopulmonary connection for complex Fontan operations. J Thorac Cardiovasc Surg 1988;96: Balaji S, Gewillig M, gull C, et al. Arrhythmias after the Fontan procedure. Circulation 1991;84(Suppl 3): Pearl JM, Laks H, Stein DG, et al. Total cavopulmonary connection versus conventional modified Fontan procedure. Ann Thorac Surg 1991;52: Miura T, Hiramatsu T, Forbess JM, Mayer JE. Effects of elevated coronary sinus pressure on coronary blood flow and left ventricular function: implications after the Fontan operation. Circulation 1995;92(Suppl 2): Van Praagh R, Weinberg PM, Smith SD, Foran RB, Van Praagh S. Malpositions of the heart. In: Adams FH, Emmanouilides GC, Riemenschneider TA, eds. Moss' heart disease in infants, children, and adolescents. Baltimore: Williams & Wilkins, 1989: Marcelletti C, Corno A, Giannico S, Marino B. Inferior vena cava-pulmonary artery extracardiac conduit: a new form of right heart bypass. J Thorac Cardiovasc Surg 1990;100: Balaji S, Johnson TB, Sade RM, et al. Management of atrial flutter after the Fontan procedure. J Am Coil Cardio11994;23: Mayer JE, Perry S, O'Brien P, et al. Orthotopic heart transplantation for complex congenital heart disease. J Thorac Cardiovasc Surg 1990;99: Fullerton DA, Campbell DN, Jones SD, et al. Heart transplantation in children and young adults: early and intermediate-term results. Ann Thorac Surg 1995;59: Kao JM, Alejos JC, Grant PW, et al. Conversion of atriopulmonary to cavopulmonary anastomosis in management of late arrhythmias and atrial thrombosis. Ann Thorac Surg 1994;58:

8 Ann ]Fhorac Surg McELHINNEY ET AL ;62: FONTAN REVISION DISCUSSION DR CARLO MARCELLETTI (Rome, Italy): I enjoyed this presentation very much; I think it brought an important message. I would like to add our experience to yours. We talk about late failure differently from acute failure. In 6 of our patients, the Fontan had to be revised several years after the operation. Four patients had received an atrial pulmonary anastomosis, and 2 patients had had an atrial ventricular anastomosis. The symptoms were congestive heart failure in all of them. Three patients presented with life-threatening supraventricular arrhythmias and 2 patients with recurrent cyanosis. Our results are comparable with those presented by Dr Hanley, and we fully agree with the rationale that reduced atrial distention, reduced pressure within the coronary sinus, and an optimal pulmonary blood flow pattern within the connection are major factors in correcting the symptoms. DR JOHN L. MYERS (Pittsburgh, PA): We have had a similar group of 7 patients with a mean age of 18 years (range, 6.9 to 31 years). The interval since the Fontan operation was 4.6 to 10.3 years (mean, 7.2 years). The mean postoperative length of stay was 8 days. The mean follow-up time is 26 months (range, 10 to 32 months). There is one feature about these patients that I would like to address. The markedly enlarged right atrium expands not only anteriorly and laterally, but also posteriorly, compressing the right pulmonary veins and also displacing the atrial septum leftward, reducing the left atrial cavity size. The conversion technique (to a total cavopulmonary connection) that we have used is very similar to what you and Dr Marcelletti have presented. It decompresses the right atrium by routing the blood from the inferior vena cava and the superior vena cava directly into the pulmonary arteries by means of a lateral baffle or tube graft. The atrial septum is excised. This decompression relieves the right pulmonary venous obstruction. The left atrial volume size is increased; therefore, there is a more compliant left atrial receiving chamber. We have been very. pleased with our results. There have been no operative or late deaths. There was improvement in the New York Heart Association class in all of our patients, 2 of whom in class IV were actually referred for cardiac transplantation. Three patients improved from class II to class I, 1 patient from class III to class 1, 1 patient from class IV to class II, and 2 patients from class IV to class ii. In your group of patients, you listed right pulmonary venous obstruction as one of the indications. My question for you is whether in fact you saw this in other patients, perhaps to a lesser degree. We believe that this is not an uncommon problem and is often not recognized in patients with the long-term atriopulmonary Fontan circulation. DR HANLEY: Thank you. It is interesting to note that all three of the experiences mentioned here in discussion are very consistent. To answer your question regarding pulmonary veins, yes, I believe that most patients with giant right atria have distorted right pulmonary veins if you look carefully. I listed only the 1 patient who had an actual hemodynamic pressure drop across his veins, which represents a severe degree of obstruction. There is a compensatory mechanism that prevents measurement of the hemodynamic pressure gradient across the veins until at a very late stage. As the pulmonary veins narrow, resistance changes cause a shift of blood toward the left lung and a reduction of flow to the right lung. The reduced flow does not allow detection of the obvious pressure gradient, which would be present if flow to the right lung were fixed. As a result, it may be very difficult to detect an obstruction until it is severe. The more subtle finding of the ribbon-like pulmonary veins behind the atrium is probably an important observation. I tend to agree with you that one does not need to prove hemodynamically that there is a gradient for the patient to gain improvement by reducing the right atrial size. DR JACQUES A. VAN SON (Leipzig, Germany): This was an excellent presentation. My experience in this area consists of four conversions to an extracardiac conduit. As in your experience, the only patient who died had protein-losing enteropathy with extensive intestinal lymphangiectasis secondary to a 3-ram gradient across an atriopulmonary anastomosis. In fact, the conversion operation seemed to exacerbate the enteropathy despite the absence of any pressure gradient in the systemic venous conduit. I believe that the role of conversion in this subset of patients needs to be defined further. Would you still perform this operation in this subset of patients? And also, was the intracardiac tunnel in your series a classic lateral tunnel or a tube graft? DR HANLEY: I think we have to be cautious in performing the Fontan revision in the group that is highly debilitated. They simply may not tolerate the insult of the operation itself. The experience, however, is very limited, essentially anecdotal, and I am not yet prepared to say that all patients in this category either should or should not undergo revision. The intracardiac tunnels were tube grafts in both cases.