CLASSICS IN THORACIC SURGERY
The Fontan Procedure: A Historical JXeview L. Douglas Cow@, MD Department of Surgery, Dean Medical Center, Madison, Wisconsin
Complete bypass of the right ventricle was first performed successfully and subsequently reported by Fontan and Baudet for patients with tricuspid atresia. By eliminating congenital and surgical shunts, ventricular volume overload and pulmonary hypertension were avoided. A logical extension of its predecessor, the
Surgical repair of tricuspid atfesia F. F O N T A N a n d E. B A U D E T Cmrn 1.C I z l d g l r . Unlrmir( I Bor&vx 11. H6liC.r clr T o d ~W . r u x .F m r
I
n 1971, Francis Fontan and Eugene Baudet reported in Thorax a new operation for tricuspid atresia [TA]. The procedure, which came to bear Fontan's name, "transmits the whole vena cava blood to the lungs while only oxygenated blood returns to the left heart"[l]. In this way, the right atrium was "ventriclized." Importantly, it only applied to sufficiently well developed children with pulmonary arteries "large enough and at sufficiently low pressure to allow a cava-pulmonary anastomosis." Fontan and Baudet emphasized this was not an anatomical correction (which would require creation of a right ventricle), but a physiological correction that suppressed shunting and avoided such hazards of systemic artery to pulmonary artery shunts as pulmonary hypertension. The procedure would eventually be recognized as a historic advance in the treatment of patients with TA. It consisted of a superior vena cava to distal right pulmonary artery anastomosis, a right atrial to proximal right pulmonary artery anastomosis, closure of atrial septal defect, ligation of main pulmonary artery, and insertion of homograft valves at the inferior vena cava-right atrial junction and right atrial to pulmonary artery anastomosis. Before 1971, shunts (systemic artery or superior vena cava to pulmonary artery) were used for the majority of TA patients with restricted pulmonary blood flow. Alternatively, a Brock procedure [2](enlargementof ventricular septal defect) was occasionally used, also to increase left-to-right shunting. Unfortunately, compared with the more common cyanotic disorders, shunts carried a higher operative mortality in TA patients, with Taussig and Bauersfeld [3] reporting a 26% &month postoperative mortality after Blalock-Taussig shunt, and Sommers and Johnson [4]finding two thirds of all patients with TA dead Address reprint requests to Dr Cow& Department of Surgery, Dean Medical Center, 1313 Fish Hatchery Rd, Madison, w1 53715.
Q 1991 by The Society of Thoracic Surgeons
partial right heart bypass procedure introduced by Glenn, the Fontan operation has great application for patients with various forms of univentricular heart. It is one of the historic advances in the surgical treatment of congenital heart disease. (Ann Thorac Surg 1991;51:1026-30)
before 1 year of age owing to congestive failure and anoxia, whether or not operation had been performed. The concept of a new operation for TA that eliminated shunting, both congenitally and surgically acquired, still stands as one of the major breakthroughs in congenital heart surgery. Fontan and Baudet credited Glenn's work [5,61 with cavopulmonary anastomosis and partial right heart bypass as the conceptual stimulus for the "therapeutic basis of the operation" [l]. They attempted the operation unsuccessfully on dogs, and concluded a normal dog heart does not allow a circulation that bypasses the right heart. However, "we were of the opinion . . a hypertrophied right atrium, as in tricuspid atresia, could supply the additional work represented by a pulmonary arterial pressure higher than the left atrial pressure, . . . but it seemed to us indispensable to provide the right atrium with valve homografts to prevent free flow between the inferior vena cava, right atrium and the pulmonary artery and, in this way, stasis in the lower half of the body and inadequate cardiac f&g"[l]. In addition to Glenn's "conceptual stimulus," considerable previous evidencehad suggested the right ventricle could occasionally be bypassed. As early as 1943, Starr and co-workers [7]destroyed approximately 75% of right ventricular musculature by cautery without producing an increase in peripheral venous pressure. Bakos (81 performed similar experiments, and concluded "an actively functioning right ventricle is not absolutely necessary for the maintenance of a normal pressure gradient in the arterial tree." Two other reports of extensive right ventricular damage being compatible with life appeared by 1954 [9,101. In a study on ventricular fibrillation, Jamison and associates [ll]perfused the systemic arterial circulation with a mechanical pump as a substitute for the left Ventricle. When arterial pressures were maintained between 120 and 205 mm Hg, blood could be driven through the systemic capillaries, the fibrillating right heart, the pulmonary circulation, and back to the left atrium. They concluded the left ventricle was capable of driving blood through both circulations without a functioning right ventricle. A cautionary note, however, was given by Rose and associates [12,131, who in repeating this experiment
.
0003-4975/91/$3.50
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CLASSICS COWGILL THE FONTAN PROCEDURE
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Fig 1 . Case I . Tricuspid atresia type 1 B. Drawing illustrates the repair: anastomosis between right atrium and proximal end of right pulmonary artery wps maa'e without interposition of an aortic valve homograft. (Reproduced from Fontan F, Baudet E . Surgical repair of tricuspid atresia. Thorax 1971;26:240-8, by permission.)
found normal blood flow through the nonfunctioning right heart could be maintained only under conditions of hypervolemia and marked venous hypertension. Rodbard and Wagner [141 experimentally bypassed the right ventricle by anastomosis of the right atrial appendage to the main pulmonary artery, demonstrating distal flow when right atrial pressure was sufficiently elevated to 9 to 14 mm saline solution. In staged operations, Warden and associates [15] first produced tricuspid stenosis in dogs and, after a period to allow right atrial hypertrophy and dilatation, subsequently performed a right atrial appendage to pulmonary artery anastomosis. They reported a few survivors and a partial regression in the elevated venous pressure, and suggested future application to the treatment of TA. Clinically, Hunvitt and associates [16] unsuccessfully attempted right atrial appendage to pulmonary artery anastomosis in a moribund, cyanotic child with univentricular heart. In discussing this report, Schumacker [17] reported three unsuccessful attempts to bypass the right heart for various cyanotic disorders. The successful results of partial right heart bypass experimentally by Glenn and Patino [5] and Robicsek and co-workers (181and clinically by Glenn [6] supported the concept of total right heart bypass for TA. From 30% to 40% of total venous return was demonstrated to pass through the superior vena cava-right pulmonary artery [5]. A tendency for chylous pleural effusions postoperatively was noted. Even though the above experimental and clinical work was completed by 1958, it would still be 10 years before Fontan and Baudet performed the first "physiologic correction." A Fontan-type correction was not even mentioned by Brock [2] in 1964 who, in reporting his unsuccessful ventricular septal defect enlargement procedure conceived a "possible radical cure" for TA in which right atrial-right ventricular continuity would be restored with a prosthetic or homograft valve inserted into the surgically resected area of atretic tricuspid valve. Fontan and Baudet's general description of surgical technique is a model for a cardiac procedure with multiple steps that minimizes myocardial ischemia. The operation
was performed through a median sternotomy. After the anatomy was verified and pulmonary artery pressure and size were measured, a Glenn shunt was performed, delaying superior vena cava ligation until the last step of the procedure to allow subsequent cannulation. Next, with clamps at the base of the right atrial appendage and the origin of the divided right pulmonary artery, an anastomosis between them was made, interposing an aortic homograft. The patient was now placed on cardiopulmonary bypass with a superior vena cava cannula and a right external iliac vein cannula (to allow insertion of the inferior vena cava-right atrial valve), snaring the superior vena cava above the Glenn anastomosis, clamping the inferior vena cava below its junction with the right atrium, venting the left ventricle, and cross-clamping the aorta. Through a right atriotomy, the atrial septal defect was closed and a pulmonary valve homograft inserted into the inferior vena caval orifice. After closure of the atriotomy, the main pulmonary artery was ligated or transected and cardiopulmonarybypass discontinued, maintaining superior vena cava, right atrial, and pulmonary artery pressures "the same or slightly higher" as those measured before bypass. After decannulation, the superior vena cava was transected at its junction with the right atrium and both ends were sutured. With this sequence, the duration of cardiopulmonary bypass was only "about 40 minutes." Three patients were reported, 2 of whom survived the operation. The first was aged 12 years at the time of Fontan correction. Cardiac catheterization demonstrateda type Ib TA, with pulmonary arteries of good size. Hematocrit preoperatively was 0.80. Operation was performed on April 25, 1968, with measured pulmonary artery pressure of 15/0 mm Hg. The procedure was as described above, except a direct right atrial appendage to pulmonary artery anastomosis was performed because a suitably small valve homograft was not available (Fig 1). Initial postoperative course was smooth, with a blood pressure of 120/60 mm Hg, normal venous pressures, and disappearance of cyanosis. Twenty-four hours postoperatively, anuria developed, corrected with hemodialysis, and melena occurred. The legs were elevated to correct the
1028 CLASSICS
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h Thorac surg 1991;51:102640
Fig 2. Case 2 . Trincspui atresia type I1 B. Drawing illustrates steps in surgical repair: (1) end-to-side anastomosis of distal end of right pulmonary artery to superior m cam; (2) end-to-end anastomosis of fight atrial appendage to prOXima1 end Of right puimonary artery by means of an aortic valw homograft; (3) closure of atrial septa1 defect; (4) insertion of a pulmonary valw homograft into inferior m cam; and (5) ligation of main pulmonary artery. (Reproduced from Fontan F, Baudet E . Surgical repair of tricuspid atresia. Thorax 1971;26:24&8, by permission.)
"stagnant inferior vena caval circulation," urine output returned, and a subsequent intravenous pyelogram demonstrated bilateral congenital hydronephrosis. A right pleural effusion required drainage 1 month postoperatively. Fontan and Baudet waited 30 months before their report, at which time the child was growing, had no exercise intolerance, and had a hematocrit of 0.52. A subsequent right atrial angiocardiogram demonstrated no inferior vena cava reflux and excellent forward flow into the left pulmonary artery. The second patient was 36 years old, with progressive exercise intolerance and cyanosis. Cardiac catheterization demonstrated type 1% TA with nearly normal sized left and right pulmonary arteries. At operation, pulmonary artery pressure was 35/0 mm Hg. The procedure as described above was performed (Fig 2), and although the initial postoperative course was smooth, to maintain adequate blood pressure both hypervolemia and tachycardia with isoproterenolwere necessary. A superior vena caval syndrome responded to diuretics, and bilateral serous pleural effusions required drainage. At the time of report, 10 months postoperatively, the patient was doing well with good exercise tolerance and decline of hematocrit from 0.80 to 0.50 with only a "moderate persistent hepatomegaly." The third patient was operated on at age 23 years and had TA with dextrocardia and low pulmonary artery pressure. Although early postoperative status was reasonable, progressive hypotension occurred in spite of volume replacement and isoproterenol6 hours postoperatively and the patient died. Autopsy demonstrated patent anastomoses but an abnormal mitral valve with vegetations, and Fontan and Baudet concluded death was due to mitral insufficiency. In discussing the patients, Fontan and Baudet noted "the striking need to provide a large amount of fluid to ensure a correct hemodynamic balance." The dispensability of the aortic valve homograft was proven by the first patient, although Fontan and Baudet believed its absence contributed to the inferior vena caval syndrome (hepatomegaly, melena, oliguria) seen in that patient. They also emphasized the advantage of low intrapulmonary airway
pressures and early extubation, the tendency for pleural effusions requiring diuretic therapy and drainage, and the importance of a normal left ventricle and mitral valve for satisfactory results. They admitted concern about the hemodynamic consequences of subsequent atrial rhythm disturbances such as fibrillation or flutter. Few new cardiac operations have proved to apply to such various pathology and to allow so many technical modificationsas the Fontan procedure. Soon after Fontan and Baudet's report, others reported successful results in TA patients with similar procedures. Kreutzer and associates [19] suggested in 1973that inferior vena caval valves and Glenn shunts were unnecessary, and used disinsertion of the pulmonic valve with atriopulmonary anastomosis effectively in 2 patients with tricuspid atresia. By 1974, three other groups had survivors with similar procedures using homografts valves [20-221. An important modification was incorporation of a hypoplastic right ventricle in an effort to augment pulmonary blood flow, as introduced by Bowman and associates [23] and modified by Bjork and co-workers [24]. Doty and co-workers [W] emphasized a posterior atriopulmonary connection, less susceptible to sternal compression, and illustrated possible modifications of surgical technique for a wide variety of great artery anatomy. Recently, deLeval and associates [26] described the "cavopulmonary anastomosis" (or "lateral tunnel technique"), which directs inferior vena caval return along the right lateral atrial wall using a patch to the superior vena cava, which is divided and each end sewn end-to-side to the right pulmonary artery. This technique is based on the concept, supported experimentally, that a uniform-sized conduit from inferior vena cava to pulmonary artery has more efficient flow than a larger atrial cavity, which contributes more turbulence. The technique commits the intraatrial defect, tricuspid valve, coronary sinus, and most of the right atrial cavity to the left-sided circulation. The procedure introduced by Fontan and Baudet became a major breakthrough not only for TA patients but for many with complex, effectively univentricular, hearts. Although septation procedures may be an alternative in a few, the inherent hazards of that procedure make a
Ann Thorac slug 1991:51:102~
passive, direct connection between the systemic venous and pulmonary arterial circulation preferable in the great majority when pulmonary artery size and resistance permit [27,281. The importance of patient selection remains paramount, with special attention to anatomical variations, timing of operation, pulmonary artery size and resistance, and technical considerations [29, 301.Patients with mean preoperative pulmonary artery pressure greater than 15 to 20 mm Hg, pulmonary vascular resistance greater than 4 U/m2, ejection fraction less than 0.45, or ventricular enddiastolic pressures greater than 25 mm Hg are poor candidates for Fontan procedures and should be considered for other palliation [31]. Operative considerations remain very important. Inferior vena caval valves are unnecessary, and prosthetic conduits and heterologous or prosthetic valves should be avoided. Glenn shunts are not mandatory in the majority, but may be advantageous (as end of superior vena cava to side of right pulmonary artery) in select patients [32],and in addition are required with the cavopulmonary technique advocated by deLeval and co-workers [26].The importance of incorporating a hypoplastic right ventricle or inserting a homograft valve into an atriopulmonary anastomosis remain controversial. Most evidence suggests a hypoplastic right ventricle subsequently provides little, if any, benefit [33-35],and consequently a direct atriopulmonary anastomosis is increasingly favored. As far as the benefit of a homograft valve in this anastomosis, a number of reports suggest a valve in this position provides little benefit and is a source of potential obstruction [35-40].An atriopulmonary valve may be of benefit, however, in patients with elevated preoperative pulmonary pressures or resistance in the critical early postoperative period to augment pulmonary blood flow. In addition, Fontan and associates [30,411 have demonstrated better late postoperative exercise capacity when a homograft valve is used. The importance of atrial contractions, likewise, is controversial, with deLeval and co-workers [26]suggesting that by creating turbulence, contractions may actually impede pulmonary blood flow. The stable condition of patients postoperatively who remain in sinus rhythm conceivably is more a reflection of ventricular function than of the advantage of an atrial contraction per se. Finally, the precepts of postoperative care emphasized in the original report by Fontan and Baudet remain critical. In approximately 20 years since the first operation, Fontan and Baudet's procedure has taken its place as one of the major advances in congenital heart surgery. By using existing knowledge and extrapolating it to properly selected patients, as well as by meticulous attention to operative and postoperative detail, Fontan and Baudet will forever be remembered for dramatically improving the prognosis of children with TA and other forms of univentricular heart.
References 1. Fontan F, Baudet E. Surgical repair of tricuspid atresia. Thorax 1971;262W.
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2. Brodc R. Tricuspid atresia: a step toward corrective treatment. J Thorac Cardiovasc Surg 1964;4717-25. 3. Taussig HB,Bauersfeld SR. Follow-up studies on the first lo00 patients operated on for pulmonary stenosis or atresia. AM Intern Med 1953;38:143. 4. Sommers SC, Johnson JM. Congenital tricuspid atresia. Am Heart J 1951;41:130-43. 5. Glenn WWL,Patino JF. Cirmlatory bypass of the right heart. Yale J Biol Med 1954;27147-51. 6. Glenn WWL.Circulatorybypass of the right side of the heart. IV. Shunt between superior vena cava and distal right pulmonary artery-report of clinical application. N Engl J Med 1958;259117-20. 7. Starr I, Jeffers WA, Meade RH.The absence of conspicuous increments of venous pressure after severe damage to the right ventricle of the dog, with a discussion of the relation between clinical congestive failure and heart disease. Am Heart J 1943;26291-301. 8. Bakos ACP. The question of the function of the right ventricular myocardium: an experimental study. C i t i o n 1950; 1(Pt 2):724-32. 9. Kagan A. Dynamic responses of the right ventricle following extensive damage by cauterization. Circulation 1952;5: 816-23. 10. Donald DE, Essex HE. Pressure studies after inactivation of the major portion of the canine right ventricle. Am J Physiol 19%;17615Sl. 11. Jamison WL, Gemeinhardt W, Alai J, Bailey CP. Artificial maintenance of the systemic circulationwithout participation of the right ventride. Circ Res 1954;2315-8. 12. Rose JC, Broida HP, Hufnagel CA,et al. A method for the study of the circulation using a mechanical left ventricle. J Appl Physiol 1 9 5 5 ; 7 W . 13. Rose JC, Cosimano SJ, Hufnagel CA, et al. The effect of exclusion of the right ventricle from the circulation in dogs. J Clin Invest 1955;34:162531. 14. Rodbard S,Wagner D. Bypassing the right ventride. Proc Soc Exper Biol Med 1949;71:6%70. 15. Warden HE, D e W d RA, Varco RL. Use of the right auricle as a pump for the pulmonary circuit. Surg Forum 1954;5:1&22. 16. Hurwitt ES, Young D, Escher DJW. The rationale of anastomosis of the right auricular appendage to the pulmonary artery in the treatment of tricuspid atresia. J Thorac Surg 1955;30:50M1. 17. Shumacker HB. Discussion of [16].J Thorac Surg 1955;30:511. 18. Robicsek A, Temesvari A, Kadar RL. A new method for the treatment of congenital heart disease associated with impaired pulmonary circulation. Acta Med Scand 1956;lW 151-61. 19. Kreutzer G, Galindez E, Bono H, et al. An operation for the correction of tricuspid atresia. J Thorac Cardiovasc Surg 1973;66.61>23. 20. Ross DN, Somerville J. Surgical correction of tricuspid atresia. Lancet 1973;1:8459. 21. Stanford W, Armstrong RG, Cline RE, et al. Right atriumpulmonary artery allograft for correction of tricuspid atresia. J Thorac Cardiovasc Surg 1973;66.105-11. 22. Miller RA, Pahlajani D, SerrattoM, et al. Clinical studies after Fontan's operation for tricuspid atresia [Abstract]. Am J Cardiol1974;33.157. 23. Bowman FO Jr, Malm JR, Hayes CJ, et al. Physiologic approach to surgery for hicuspid atresia. Circulation 1978; %(Pt 3):83-6. 24. Bjdrk VO, Olin CL, Bjarke BB, et al. Right a s r i g h t
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ventricular anastomosis for correction of tricuspid atresia. J Thorac Cardiovasc Surg 1979;77:45243. 25. Doty DB, Marvin WJJr, Lauer RM. Modified Fontan procedure: methods to achieve direct anastomosis of the right atrium to pulmonary artery. J Thorac Cardiovasc Surg 1981; 81:47&5. 26. DeLeval MR, Kilner P, Gewilling M, et al. Total cavopulmonary connection: a logical alternative to atriopulmonary connection for complex Fontan operations. J Thorac Cardiovasc Surg 19&3;96682-95. 27. Feldt RH,Mair DD, Danielson GK, et al. Current status of the septation procedure for univentricular heart. J Thorac Cardiovasc Surg 1981;8293-7. 28. McKay R, Pacific0 AD, Blackstone EH, et al. Septation of the univentricular heart with subaortic outlet chamber. J Thorac Cardiovasc Surg 1982;84:77-87. 29. Choussat A, Fontan F, Besse P, et al. Selection criteria for Fontan‘s procedure. In: Anderson RH, ShinebourneEA, eds. Paediatric cardiology. Edinburgh: Churchill Livingstone, 1977:55%70. 30. Fontan F, Deville C, Quaegebeur J, et al. Repair of tricuspid atresia in 100 patients. J Thorac Cardiovasc Surg 1983;85: 647-60. 31. Haas GS, Laks H, Pearl JP. Modified Fontan procedure. Adv Card Surg 199O;l:lll-54. 32. Pennington DG,Noun S, Ho J, et al. Glenn shunt: long-term results and current role in congenital heart operations. Ann Thorac Surg 1981;31:532-9. 33. Lee CN, Schaff HV, Danielson GK, et al. Comparison of atriopulmonary versus atrioventricular connections for mod-
Ann Thorac Surg 1991;51:102640
ified Fontan/Kreutzer repair of tricuspid valve atresia. J Thorac Cardiovasc Surg 1986;92103&43. 34. Bull C, deLeval MR, Stark J, et al. Use of a subpulmonary ventricular chamber in Fontan cirmlation. J Thorac Cardiovasc Surg 1983;85.2131. 35. DiSessa TG, Child JS, Perloff JK, et al. Systemic venous and pulmonary arterial flow patterns after Fontan’s procedure for tricuspid atresia or single ventricle. Circulation 1984;70 898-902. 36. Kreutzer GO, Vargas FJ,Schlicht AJ, et al. A t r i ~ p u l m o ~ r y anastomosis. J Thorac Cardiovasc Surg 1982;83.427-36. 37. Ishikawa T, Neutze JM, Brandt PWT, et al. Hemodynamics following the Kreutzer procedure for tricuspid atresia in patients under 2 years of age. J Thorac Cardiovasc Surg 1984;88:373-9. 38. Shemin RJ, Merrill WH, Pfeifer JS, et al. Evaluation of right atrial pulmonary conduits for tricuspid atresia. J Thorac Cardiovasc Surg 1979;77:6t590. 39. Laks H, Williams WG, Hellenbrand WE, et al. Results of right atrial to right ventricular and right atrial to pulmonary artery conduits for complex congenital heart disease. Ann Surg 1980;192382-9. 40. Gale AW, Danielson GK, McGoon DC, et al. Modified Fontan operation for univentricular heart and complicated congenital lesions. J Thorac Cardiovasc Surg 1979;78831-8. 41. Ottenkamp J, Rohmer J, Quaegebeur JM, et al. Nine years’ experience with physiologic repair of tricuspid atresia: long term results and current surgical approach. Thorax 1982;37 718-26.
The Fontan Procedure: A Historical JXeview L. Douglas Cow@, MD Department of Surgery, Dean Medical Center, Madison, Wisconsin
Complete bypass of the right ventricle was first performed successfully and subsequently reported by Fontan and Baudet for patients with tricuspid atresia. By eliminating congenital and surgical shunts, ventricular volume overload and pulmonary hypertension were avoided. A logical extension of its predecessor, the
Surgical repair of tricuspid atfesia F. F O N T A N a n d E. B A U D E T Cmrn 1.C I z l d g l r . Unlrmir( I Bor&vx 11. H6liC.r clr T o d ~W . r u x .F m r
I
n 1971, Francis Fontan and Eugene Baudet reported in Thorax a new operation for tricuspid atresia [TA]. The procedure, which came to bear Fontan's name, "transmits the whole vena cava blood to the lungs while only oxygenated blood returns to the left heart"[l]. In this way, the right atrium was "ventriclized." Importantly, it only applied to sufficiently well developed children with pulmonary arteries "large enough and at sufficiently low pressure to allow a cava-pulmonary anastomosis." Fontan and Baudet emphasized this was not an anatomical correction (which would require creation of a right ventricle), but a physiological correction that suppressed shunting and avoided such hazards of systemic artery to pulmonary artery shunts as pulmonary hypertension. The procedure would eventually be recognized as a historic advance in the treatment of patients with TA. It consisted of a superior vena cava to distal right pulmonary artery anastomosis, a right atrial to proximal right pulmonary artery anastomosis, closure of atrial septal defect, ligation of main pulmonary artery, and insertion of homograft valves at the inferior vena cava-right atrial junction and right atrial to pulmonary artery anastomosis. Before 1971, shunts (systemic artery or superior vena cava to pulmonary artery) were used for the majority of TA patients with restricted pulmonary blood flow. Alternatively, a Brock procedure [2](enlargementof ventricular septal defect) was occasionally used, also to increase left-to-right shunting. Unfortunately, compared with the more common cyanotic disorders, shunts carried a higher operative mortality in TA patients, with Taussig and Bauersfeld [3] reporting a 26% &month postoperative mortality after Blalock-Taussig shunt, and Sommers and Johnson [4]finding two thirds of all patients with TA dead Address reprint requests to Dr Cow& Department of Surgery, Dean Medical Center, 1313 Fish Hatchery Rd, Madison, w1 53715.
Q 1991 by The Society of Thoracic Surgeons
partial right heart bypass procedure introduced by Glenn, the Fontan operation has great application for patients with various forms of univentricular heart. It is one of the historic advances in the surgical treatment of congenital heart disease. (Ann Thorac Surg 1991;51:1026-30)
before 1 year of age owing to congestive failure and anoxia, whether or not operation had been performed. The concept of a new operation for TA that eliminated shunting, both congenitally and surgically acquired, still stands as one of the major breakthroughs in congenital heart surgery. Fontan and Baudet credited Glenn's work [5,61 with cavopulmonary anastomosis and partial right heart bypass as the conceptual stimulus for the "therapeutic basis of the operation" [l]. They attempted the operation unsuccessfully on dogs, and concluded a normal dog heart does not allow a circulation that bypasses the right heart. However, "we were of the opinion . . a hypertrophied right atrium, as in tricuspid atresia, could supply the additional work represented by a pulmonary arterial pressure higher than the left atrial pressure, . . . but it seemed to us indispensable to provide the right atrium with valve homografts to prevent free flow between the inferior vena cava, right atrium and the pulmonary artery and, in this way, stasis in the lower half of the body and inadequate cardiac f&g"[l]. In addition to Glenn's "conceptual stimulus," considerable previous evidencehad suggested the right ventricle could occasionally be bypassed. As early as 1943, Starr and co-workers [7]destroyed approximately 75% of right ventricular musculature by cautery without producing an increase in peripheral venous pressure. Bakos (81 performed similar experiments, and concluded "an actively functioning right ventricle is not absolutely necessary for the maintenance of a normal pressure gradient in the arterial tree." Two other reports of extensive right ventricular damage being compatible with life appeared by 1954 [9,101. In a study on ventricular fibrillation, Jamison and associates [ll]perfused the systemic arterial circulation with a mechanical pump as a substitute for the left Ventricle. When arterial pressures were maintained between 120 and 205 mm Hg, blood could be driven through the systemic capillaries, the fibrillating right heart, the pulmonary circulation, and back to the left atrium. They concluded the left ventricle was capable of driving blood through both circulations without a functioning right ventricle. A cautionary note, however, was given by Rose and associates [12,131, who in repeating this experiment
.
0003-4975/91/$3.50
Ann Thorac Surg 1991;51:102630
CLASSICS COWGILL THE FONTAN PROCEDURE
1027
Fig 1 . Case I . Tricuspid atresia type 1 B. Drawing illustrates the repair: anastomosis between right atrium and proximal end of right pulmonary artery wps maa'e without interposition of an aortic valve homograft. (Reproduced from Fontan F, Baudet E . Surgical repair of tricuspid atresia. Thorax 1971;26:240-8, by permission.)
found normal blood flow through the nonfunctioning right heart could be maintained only under conditions of hypervolemia and marked venous hypertension. Rodbard and Wagner [141 experimentally bypassed the right ventricle by anastomosis of the right atrial appendage to the main pulmonary artery, demonstrating distal flow when right atrial pressure was sufficiently elevated to 9 to 14 mm saline solution. In staged operations, Warden and associates [15] first produced tricuspid stenosis in dogs and, after a period to allow right atrial hypertrophy and dilatation, subsequently performed a right atrial appendage to pulmonary artery anastomosis. They reported a few survivors and a partial regression in the elevated venous pressure, and suggested future application to the treatment of TA. Clinically, Hunvitt and associates [16] unsuccessfully attempted right atrial appendage to pulmonary artery anastomosis in a moribund, cyanotic child with univentricular heart. In discussing this report, Schumacker [17] reported three unsuccessful attempts to bypass the right heart for various cyanotic disorders. The successful results of partial right heart bypass experimentally by Glenn and Patino [5] and Robicsek and co-workers (181and clinically by Glenn [6] supported the concept of total right heart bypass for TA. From 30% to 40% of total venous return was demonstrated to pass through the superior vena cava-right pulmonary artery [5]. A tendency for chylous pleural effusions postoperatively was noted. Even though the above experimental and clinical work was completed by 1958, it would still be 10 years before Fontan and Baudet performed the first "physiologic correction." A Fontan-type correction was not even mentioned by Brock [2] in 1964 who, in reporting his unsuccessful ventricular septal defect enlargement procedure conceived a "possible radical cure" for TA in which right atrial-right ventricular continuity would be restored with a prosthetic or homograft valve inserted into the surgically resected area of atretic tricuspid valve. Fontan and Baudet's general description of surgical technique is a model for a cardiac procedure with multiple steps that minimizes myocardial ischemia. The operation
was performed through a median sternotomy. After the anatomy was verified and pulmonary artery pressure and size were measured, a Glenn shunt was performed, delaying superior vena cava ligation until the last step of the procedure to allow subsequent cannulation. Next, with clamps at the base of the right atrial appendage and the origin of the divided right pulmonary artery, an anastomosis between them was made, interposing an aortic homograft. The patient was now placed on cardiopulmonary bypass with a superior vena cava cannula and a right external iliac vein cannula (to allow insertion of the inferior vena cava-right atrial valve), snaring the superior vena cava above the Glenn anastomosis, clamping the inferior vena cava below its junction with the right atrium, venting the left ventricle, and cross-clamping the aorta. Through a right atriotomy, the atrial septal defect was closed and a pulmonary valve homograft inserted into the inferior vena caval orifice. After closure of the atriotomy, the main pulmonary artery was ligated or transected and cardiopulmonarybypass discontinued, maintaining superior vena cava, right atrial, and pulmonary artery pressures "the same or slightly higher" as those measured before bypass. After decannulation, the superior vena cava was transected at its junction with the right atrium and both ends were sutured. With this sequence, the duration of cardiopulmonary bypass was only "about 40 minutes." Three patients were reported, 2 of whom survived the operation. The first was aged 12 years at the time of Fontan correction. Cardiac catheterization demonstrateda type Ib TA, with pulmonary arteries of good size. Hematocrit preoperatively was 0.80. Operation was performed on April 25, 1968, with measured pulmonary artery pressure of 15/0 mm Hg. The procedure was as described above, except a direct right atrial appendage to pulmonary artery anastomosis was performed because a suitably small valve homograft was not available (Fig 1). Initial postoperative course was smooth, with a blood pressure of 120/60 mm Hg, normal venous pressures, and disappearance of cyanosis. Twenty-four hours postoperatively, anuria developed, corrected with hemodialysis, and melena occurred. The legs were elevated to correct the
1028 CLASSICS
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THE FONTAN PROCEDURE
h Thorac surg 1991;51:102640
Fig 2. Case 2 . Trincspui atresia type I1 B. Drawing illustrates steps in surgical repair: (1) end-to-side anastomosis of distal end of right pulmonary artery to superior m cam; (2) end-to-end anastomosis of fight atrial appendage to prOXima1 end Of right puimonary artery by means of an aortic valw homograft; (3) closure of atrial septa1 defect; (4) insertion of a pulmonary valw homograft into inferior m cam; and (5) ligation of main pulmonary artery. (Reproduced from Fontan F, Baudet E . Surgical repair of tricuspid atresia. Thorax 1971;26:24&8, by permission.)
"stagnant inferior vena caval circulation," urine output returned, and a subsequent intravenous pyelogram demonstrated bilateral congenital hydronephrosis. A right pleural effusion required drainage 1 month postoperatively. Fontan and Baudet waited 30 months before their report, at which time the child was growing, had no exercise intolerance, and had a hematocrit of 0.52. A subsequent right atrial angiocardiogram demonstrated no inferior vena cava reflux and excellent forward flow into the left pulmonary artery. The second patient was 36 years old, with progressive exercise intolerance and cyanosis. Cardiac catheterization demonstrated type 1% TA with nearly normal sized left and right pulmonary arteries. At operation, pulmonary artery pressure was 35/0 mm Hg. The procedure as described above was performed (Fig 2), and although the initial postoperative course was smooth, to maintain adequate blood pressure both hypervolemia and tachycardia with isoproterenolwere necessary. A superior vena caval syndrome responded to diuretics, and bilateral serous pleural effusions required drainage. At the time of report, 10 months postoperatively, the patient was doing well with good exercise tolerance and decline of hematocrit from 0.80 to 0.50 with only a "moderate persistent hepatomegaly." The third patient was operated on at age 23 years and had TA with dextrocardia and low pulmonary artery pressure. Although early postoperative status was reasonable, progressive hypotension occurred in spite of volume replacement and isoproterenol6 hours postoperatively and the patient died. Autopsy demonstrated patent anastomoses but an abnormal mitral valve with vegetations, and Fontan and Baudet concluded death was due to mitral insufficiency. In discussing the patients, Fontan and Baudet noted "the striking need to provide a large amount of fluid to ensure a correct hemodynamic balance." The dispensability of the aortic valve homograft was proven by the first patient, although Fontan and Baudet believed its absence contributed to the inferior vena caval syndrome (hepatomegaly, melena, oliguria) seen in that patient. They also emphasized the advantage of low intrapulmonary airway
pressures and early extubation, the tendency for pleural effusions requiring diuretic therapy and drainage, and the importance of a normal left ventricle and mitral valve for satisfactory results. They admitted concern about the hemodynamic consequences of subsequent atrial rhythm disturbances such as fibrillation or flutter. Few new cardiac operations have proved to apply to such various pathology and to allow so many technical modificationsas the Fontan procedure. Soon after Fontan and Baudet's report, others reported successful results in TA patients with similar procedures. Kreutzer and associates [19] suggested in 1973that inferior vena caval valves and Glenn shunts were unnecessary, and used disinsertion of the pulmonic valve with atriopulmonary anastomosis effectively in 2 patients with tricuspid atresia. By 1974, three other groups had survivors with similar procedures using homografts valves [20-221. An important modification was incorporation of a hypoplastic right ventricle in an effort to augment pulmonary blood flow, as introduced by Bowman and associates [23] and modified by Bjork and co-workers [24]. Doty and co-workers [W] emphasized a posterior atriopulmonary connection, less susceptible to sternal compression, and illustrated possible modifications of surgical technique for a wide variety of great artery anatomy. Recently, deLeval and associates [26] described the "cavopulmonary anastomosis" (or "lateral tunnel technique"), which directs inferior vena caval return along the right lateral atrial wall using a patch to the superior vena cava, which is divided and each end sewn end-to-side to the right pulmonary artery. This technique is based on the concept, supported experimentally, that a uniform-sized conduit from inferior vena cava to pulmonary artery has more efficient flow than a larger atrial cavity, which contributes more turbulence. The technique commits the intraatrial defect, tricuspid valve, coronary sinus, and most of the right atrial cavity to the left-sided circulation. The procedure introduced by Fontan and Baudet became a major breakthrough not only for TA patients but for many with complex, effectively univentricular, hearts. Although septation procedures may be an alternative in a few, the inherent hazards of that procedure make a
Ann Thorac slug 1991:51:102~
passive, direct connection between the systemic venous and pulmonary arterial circulation preferable in the great majority when pulmonary artery size and resistance permit [27,281. The importance of patient selection remains paramount, with special attention to anatomical variations, timing of operation, pulmonary artery size and resistance, and technical considerations [29, 301.Patients with mean preoperative pulmonary artery pressure greater than 15 to 20 mm Hg, pulmonary vascular resistance greater than 4 U/m2, ejection fraction less than 0.45, or ventricular enddiastolic pressures greater than 25 mm Hg are poor candidates for Fontan procedures and should be considered for other palliation [31]. Operative considerations remain very important. Inferior vena caval valves are unnecessary, and prosthetic conduits and heterologous or prosthetic valves should be avoided. Glenn shunts are not mandatory in the majority, but may be advantageous (as end of superior vena cava to side of right pulmonary artery) in select patients [32],and in addition are required with the cavopulmonary technique advocated by deLeval and co-workers [26].The importance of incorporating a hypoplastic right ventricle or inserting a homograft valve into an atriopulmonary anastomosis remain controversial. Most evidence suggests a hypoplastic right ventricle subsequently provides little, if any, benefit [33-35],and consequently a direct atriopulmonary anastomosis is increasingly favored. As far as the benefit of a homograft valve in this anastomosis, a number of reports suggest a valve in this position provides little benefit and is a source of potential obstruction [35-40].An atriopulmonary valve may be of benefit, however, in patients with elevated preoperative pulmonary pressures or resistance in the critical early postoperative period to augment pulmonary blood flow. In addition, Fontan and associates [30,411 have demonstrated better late postoperative exercise capacity when a homograft valve is used. The importance of atrial contractions, likewise, is controversial, with deLeval and co-workers [26]suggesting that by creating turbulence, contractions may actually impede pulmonary blood flow. The stable condition of patients postoperatively who remain in sinus rhythm conceivably is more a reflection of ventricular function than of the advantage of an atrial contraction per se. Finally, the precepts of postoperative care emphasized in the original report by Fontan and Baudet remain critical. In approximately 20 years since the first operation, Fontan and Baudet's procedure has taken its place as one of the major advances in congenital heart surgery. By using existing knowledge and extrapolating it to properly selected patients, as well as by meticulous attention to operative and postoperative detail, Fontan and Baudet will forever be remembered for dramatically improving the prognosis of children with TA and other forms of univentricular heart.
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