Pulmonary Artery Connection in the Fontan Procedure

Pulmonary Artery Connection in the Fontan

Procedure*

Flexible Polytetrafluoroethylene Conduit for Expansion Sugato Nawa, M.D.; Takanobu Matsuki, M.D.; Akira Shimizu, M.D.; Akira Kurita, M.D.; Mamoro Tago, M.D.; Taiji Murakami, M.D.;

Yoshimasa Senoo, M.D.; and Shigero Teramoto, M.D., F.C.C.P.

From clinical experiences with the Fontan operation in six cases, a few practical contrivances and operative steps are described. We stress that meticulous care should be taken not to cause any stenotic complication in the outflow tract toward the pulmonary artery, particularly by traction of the right atrial appendage only to achieve a direct anastomosis. Conduit repair would be necessitated by cases in order to expand the indicative criteria vertically as well as horizontally. For conduit material, we used consecutively nonvalved

polytetrafluoroethylene that was reinforced by handmade stainless steel wire ring (Gore-Tex, Inc) or by spirally built-in stent (IMPRA, Inc), The latter was eventually useful in obtaining natural curving of the conduit without kinking or compression. Some contrivances in anastomosing a conduit were also proposed to achieve an excellent result. We believe these practical contrivances will serve for expansion of the indicative criteria and promise improved operative outcome.

In 1971, Fontan and Bauder originally reported an operation for physiologic correction of tricuspid atresia. Since then, the concept of Fontans circulation has been applied to correct various complicated cardiac malformationsv' that had been previously considered uncorrectable, and the procedure itself has been modified in various fashions. 2-4 There still remain controversial problems: to use or not to use valves and/or conduit. 1-7 We did not focus on those problems, but propose practical contrivances to accomplish right atrium-pulmonary artery connection with or without a conduit from a surgeons view point, though our series of patients was small.

between the superior venae cavae. Hepatocardiac vein and absence of coronary sinus were also noted.

PATIENTS AND METHODS

Six consecutive patients, aged seven to 21 years (mean age of 12.8 years), were operated on by the modified Fontan procedure. Indicated anomalies are listed in Table 1, and ranged from tricuspid atresia (type lIb) to cor biloculare with complete endocardial cushion defect, an incompetent common atrioventricular valve, and transposed great arteries (ILL). Other associated anomalies, previous palliative operations and the operative outcome were also presented. Concerning the indications proposed by Choussat," only two patients (cases 1 and 3) had normally developed pulmonary arteries; the remaining four had shown small pulmonary arteries. Besides, case 5 had been associated with an incompetent common atrioventricular valve and anomalous systemic venous drainage. The anomalous drainage involved the right superior caval vein which drained directly into the anatomic left:atrium and the left:caval vein into the anatomic right atrium; there were no communications ·From the Second Department of Surgery, Okayama University Medical School, Olcayama, Japan. Manuscript received April 7; revision accepted October 17. Reprint requests: Dr. Nawa, Second D~rtment of Surgery, OlCafl4mt1 UnitJenity MedictJl School, 20501 Shilcata-chO, Okai/ama

City, Japan 700

Operative Techniques and Contrivances The basic operative procedures to connect the right atrium to the pulmonary artery and the methods of closing atrial septal defect(s) are Ulustrated in Figure 1. No valves were consecutively placed on cava-atrial junction or between the right atrium and the pulmonary artery.

Direct Anastomosis The direct anastomosis of the right atrium to the pulmonary artery was done in three patients (cases 1, 2 and 5). The juxtaposed right atrial appendage was advantageous geometrically to achieve direct anastomosis behind the aorta. Since the juxtaposed right atrial appendage was incomplete in case 1, the anastomosis was done on the right side and posterior to the aorta. In case 2, it was achieved on the left:side to the aorta, since the juxtaposition was complete. The direct anastomosis without a patch was done the first time in case 2. Stenosis of the outflow tract occurred even with a sufficient anastomotic orifice, so the anastomosis was corrected immediately with a patch. There were two causative findings for the stenosis, illustrated in Figure 2 (arrows). One was too much traction on the right atrial appendage to achieve the direct anastomosis near the pulmonary bifurcation with a cut-in to the left:pulmonary artery, since the trunk was hypoplastic. This procedure caused stenosis at the transitional portion to the appendage (Fig 2, arrow a). A patch was useful in reducing the traction as well as obtaining wider anastomotic orifice. Another was the result of a direct suture closure of multiple atrial septal defects, by which the entrance to the appendage became narrower (Fig 2, arrow b) due to tense flooring (retracted atrial septum). The juxtaposed right atrial appendage was usually smaller than that of normal position, and the entrance to the appendage was always narrow particularly in the case of complete form. Careful attention should have been paid to this point. In case 5, complicated cavo-pulmonary anastomosis was performed, as illustrated in Figure 1. The hepatocardiac vein, that drained directly in the left: atrium, was left: untouched. Atrial Pulmonary Artery ConnectIon

In Fontan Procedure (Nawaet III)

Table I-Clinical Cae. Cases

Associated Anomalies

Diseases

Age/Sex

1

191M

TA (lIb)

2

100F

3

71F

DORV(SDD, non-com VSD fA

4

7/F

fA

5

211M

6

131M

TGA (III), SA, SV: C-ECD TA (Ib)

ASD, VSD, Juxta-RAA ASD, LSVC, TS, PS, Juxta-RAA fDA, ASD, TS, Hypoplastic RV fDA, ASD, TS, Hypoplastic RV Bi-SVC, Hepatocard. CS (- ) ASD, VSD, Hypoplastic RV

v:

Previous Operation

Results NYHA

(-)

Alive

Lt-Blalock

1 Dead

Lt-Blalock

Alive

(-)

1 Alive

Rt-Blalock

1 Dead

Lt-Blalock Glenn

Alive 1

Abbreviations: TA. bicuspid atresia; DOH\; double outlet right ventricle. SDD, situs solitus, D-loop, D-position; non-com. VSD, noncommitted ventricular septal defect; PA, pulmonary atresia; TGA, transposed great arteries; SA, single atrium; SV: single ventricle; C-ECD, complete endocardial cushion defect; ASD, atrial septal defect; Juxta-RAA, juxtaposition of right atrial appendage; LSVC, left superior vena cava; TS, tricuspid stenosis; PS, pulmonary stenosis; fDA, patent ductus arteriosus; Hypo-R~ hypoplastic right ventricle; Bi-SVC, bilateral superior venae cavae; Hepatocard hepatocardiac vein; CS, coronary sinus; and NYHA, New YorkHeart Association.

v:

septation with a Dacron patch and replacement of the incompetent common atrioventricular valve were done simultaneously. The postoperative course ofthispatient was eventful; the patient suffered from multi-organ taIIure and died 25 days later. Hepatomegaly and inarked ascites were particular problems in this patient even after recovery from a low cardiac output state.

Conduit Repair Tubular prosthetic nonvalved conduit was used to connect the right atrium to the pulmonary artery in the remaining three cases (cases 3, 4 and 6, Fig 1). The material used was polytetraftuoroethylene (PTFE), and the conduit diameter was 22 mm (Gore-Tex, Inc), 20 mm (Gore- Tex, Inc) and 19 mm (IMPRA, Inc) in cases 3, 4

and 6, respectively. In all, the conduit was placed in front of the aorta. A straight conduit was used in case 3, in which the pulmonary arterial size was normal, whtle in cases 4 and 6, curved conduit was applied, since development of the pulmonary artery, as well as subpulmonic conus was so poor thatthe pulmonary trunk was retracted posteriorly. To manage thisunfavorable geometric con6guration, the curved conduit was very useful. In case 4, the curved conduit was made perioperatively, and a flexible conduit (IMfRA, PTFE) was utilized in case 6. To make a curved conduit, some contrivances were proposed, as follCM The connected portion of the two parts of conduit was reinforced using a hand-made stainless steel wire ring to keep the fun internal diameter and to protect from sternal compression. More-

Case 1

Case 2

Case 3

Case 4

Case 5

Case 6

FIGURE

1. Schematic illustration of basic procedure for right atrium-pulmonary artery connection. The

direct anastomosis and direct suture closure of atrial septal defect(s) were done by three cases. A tubular reinfOrced non-valved conduit was utilized in other three cases. No valves were used in any position. CHEST I 91 I 4 I APRIL, 18S7

553

(Case 3) Conduit

PA

(Case 4)

PA (Case 6) FIGURE 2. Anatomic consideration ~r stenotic complication in juxtaposition right atrial appendage (case 2). Stenosis (aJ"I"O\lv, a) was caused by unnecessary tractionof the appendage to produce direct anastomosis, and the other (aJ"I"O\lv, b) was derived from direct suture closure of multiple atrial septal defects. over, the directions of the cross-sectional surface of connected part and two cut ends should be so created as to get a naturalcurvtng, geometric configuration and fitting with a space, as illustrated in Fipre 3. This maneuver would provide smooth blood flow to the pulmonary artery. On the other hand, in case 6, a flexible conduit was utilizeci, and was easy to achieve a natural curving. For preparation of the conduit stumps, the direction of cut-end surface should be created to face the pulmonary artery and the amputated right atrial appendage to be anastomosed. These contrivances are shown in Figure 3. The conduit materials (PrFE) were vulnerable to compression from the outside, so the stainless steel wire was rolled in spiral fashion outside a conduit. The wire ring of the same kind was abo sutured to the anastomosis orifice of the right atrium to keep full expansion of the orifice and not to collapse even when dehydration occurred. ilESUI.:rS

The operative outcome is shown in "Iable 1. Two patients with direct anastomosis of the right atrium to the pulmonary artery were lost, while all three patients with conduit operation survived. The late postoperative states of four surviving patients are gratifying. They are class 1 of the New York Heart Association, play sports and are active. Case 2 was lost due to uncontrollable bleeding and low cardiac output after the second operation. The 554

FICUBE 3. Conbivances for conduit repair. Horizontally trailsectiooal illUstrations are presented on the left and sagittally transectiona! on the right.

residual reverse shunt through directly closed multiple atrial septal defects involving inferior sinus venosus type necessitated the second operation. At the second operation, it was revealed that the tract to the right atrial appendage had been stenotic due to the operative procedure already discussed, but this complication was left: uncorrected. This would be one of the major causes of mortality, we thought retrospectively. Case 5 was also lost after 25 days from multi-organ failure after lowcardiac output state. Two patients were lost in this small series; however, even those were able to survive the operation with more meticulous operative considerations to be discussed later The intraoperative photograph of case 4 is presented (Fig 4),. showing the anastomosis using a curved conduit that was reinforced by stainless steel wire. The postoperative atriogram is shown in Figure 5. Combined With the Intraoperative photograph, the angiocardiograms of biplane projections proved a beautiful geometrical configuration as well as excellent blood flow to the pulmonary artery via a curved conduit. The same results were obtained in cases 6 and 3. No compression by either the sternum or the aorta was observed, being protected by re-inforcing maneuvers. The surviving three patients with conduits were placed on control with anticoagulant therapy (warfarin) Pulmonary Artery Connection in Fontan Procedure (Haws et aI)

and monitored monthly. The implanted conduit was examined periodically by pulsed Doppler and 2-D echocardiography, Neither thrombotic obstruction nor luminal narrowing due to thick intimal peel has been observed during 4.8, 3.8 and 1.0 year follow-upin cases 3, 4, and 6, respectively. DISCUSSION

FICURE 4. Intraoperative photograph (case 4). A wire reinforced curved conduit (polytetrafluoroethylene) is shown, and gave a natural fitting and excellent geometric configuration .

Many experimental and clinical investigations of Fontan circulation'r" suggested that valves could be eliminated from the Fontan procedure. Among these, a report by Nakazawa et alJ3 strongly suggested possibility of elimination. Moreover, the clinical report by Kreitman et al" of total cavopulmonary shunt was one of the clinical proofs of the possibility to sustain the pulmonary circulation without valves or right atrium . These considerations led us not to use any valve in right atrium-pulmonary anastomosis. To use or not to use conduit for anastomosis of the right atrium to the pulmonary artery was another controversial subject. Many reports':' have recommended the utilization of native tissues as much as possible instead of conduit. Doty et al' proposed techniques to utilize autogenous structures exclusively, and described that a large diameter direct anastomosis of the right atrium to the pulmonary artery nearly always was possible. We also agree with the policy as we did in cases 1, 2 and 5. However, meticulous attention should be paid

FICURE 5. Postoperative right abiogram (case 4). It was clearly shown that the curved conduit kept its geometric configuration and brought a sufficient blood flow to the pulmonary artery. The wire reinforcing maneuver was really useful.

CHEST I 91 I 4 I APRIL, 1987

555

two times the venous return from a normal superior

FIGURE 6. Alternative anostomosis procedure for case 5. This procedure was contrived retrospectively. This case taught us the importance of consideration ofblood flow volume from the superior as well as inferior vena cava.

not to cause any stenotic lesion by unnecessary traction only to achieve direct anastomosis, as our initial trial in case 2. Besides, as in case 5, the direct cavopulmonary anastomosis was indeed possible, but in this anastomosis complex, the proximal small left superior vena cava that had carried one half of the venous return from the upper body half was used as a carrier of the venous return from the inferior vena cava, that amounted to

vena cava. This resulted in an insufficient outlet orifice from the right atrium. More precise anastomosis should have been considered. A retrospectively contrived and more favorable anastomosis is illustrated in Figure 6 using a conduit to obtain larger anastomotic orifice. This procedure would prevent possible occurrence of sinoatrial block or the damage of sinus node itself that might be caused by direct enlargement of superior cavo-atrialjunction with a patch. There must be some case in which the conduit repair is inevitable to achieve a sufficient anastomotic diameter, since the Fontan criteria has been expanded markedly today. That is, one of ten observes a case with moderate size distal pulmonary arteries in spite of a very hypoplastic or even atretic pulmonary trunk. These cases are indications today for the Fontan operation, since conduit can bridge the right atrium and distal pulmonary arteries instead of the pulmonary trunk. As for the conduit materials, autologous vein and various prosthetic materials are satisfactory for the reconstruction of arteries and left heart obstructions, whereas attempts at venous replacement and right heart reconstruction with similar materials have been disappointing. After similar experiences with the graft failure in superior vena cava (SVC) and/or brachiocephalic vein reconstruction using woven Dacron or TeHon, we started using PTFE for surgical correction in patients with the SVC syndrome in 1976. These patients are listed in Table 2, and non-supported PTFE was used in cases 1 and 2, and externally stented Hexible PTFE was adopted in cases 3, 4, and 5, recently. This series showed an excellent patency with PTFE for

Table 2-Clinical CtuJe8 ofSVC Syndrome Corrected by Polytetrafluoroethylene (PTFE) Graft Graft

Case

Age/Sex 31F

Diagnosis

Operative Procedure

Fibrosing granulomatous mediastinitis Metastatic carcinoma

Resection of SVC with pericardium. Reronst. of SVC Resection of tumor and SVC with Bil. BCVs. Reronst. of Bil. BCVs Thymectomy, Resection ofLt. BCV Beeonst. of Lt. BCV Thymectomy, Resection of SVC with Bil. BCVs Reconst. of Lt. BCV Thymectomy, Resection ofLt. BCV Reronst. of Lt. BCV

2

48/M

3

42/M

Invasive thymoma

4

661M

Invasive thymoma

5

221M

Invasive thymoma

Follow-up (patency)

D (mm)

L (mm)

Gore-Tex

10

40

9 days (patent)

Gore-Tex

10 10

80

3 months (Patent)

Externally stented Gore-Tex Externally stented Gore-Tex Externally stented Gore-Tex

10

50

12

80

9 months (probably patent) 3 months (Patent)

10

40

Material

70

2 months (Patent)

Though case 1 was lost through multi-organ failure, and cases 2 and 4 were lost due to primary lesions, the graft patency was assured by autopsy in cases 1 and 4, and in case 2 no sign of SVC syndrome was noted until he expired. No sign of graft obstruction or stenosis due to thrombosis or intimal over-proliferation was observed with Gore- Tex (FfFE) graft. Op: operative; D: diameter; L: length; SVC: superior vena cava; Reconst.: reconstruction; Bil: bilateral; BCV(s): brachiocephalic vein(s).

558

PulmonaryArtery Connection in Fontan Procedure (Nawa et 81)

the thoracic vena cava and brachiocephalic vein reconstructions. PTFE is a relatively inert, almost nonwettable and collapsible synthetic polymer with the 30 f.L pore size. The type of externally stented graft is manufactured, up to 16 mm in diameter, by Gore and Associates, Inc, and is also manufactured, up to 19 mm, by IMPRA Inc, and are clinically available today. The clinical difference between the two registered trademarks of GoreTex and IMPRA-Flex is not yet cleat; but we have prefered IMPRA-Flex in case 6 because of the larger diameter; The externally stented PTFE was really useful to achieve a natural curving without any kinking or stenosis, keeping the circular lumen throughout the graft and preventing external compression. Fiore et allS reported an experimental study of prosthetic replacement for the thoracic vena cava, where they described that stented PTFE exhibited a patency rate equal to that of autologous vein at 30 days, minimal graft reaction, excellent incorporation by host fibroblasts, and a smooth intima. Other investigators have demonstrated uniformly poor results with synthetic textile fabrics, such as knitted or woven Dacron in the venous system, showing a tendency toward progressive stenosis and obstruction from thick collapsible neointimal lining. 16-18 Taking all these circumstances and our own experience with SVC reconstruction into consideration, we have used externally reinforced PTFE for the conduit repair of the modified Fontan procedure. Recently, Brown et al19 reported an experimental comparison of PTFE with Dacron valved conduit for right heart reconstruction. They described that the neointima in externally stented PTFE conduits was thin and uniform and the conduits warrant clinical application, supporting our clinical series. Our second look in the case of a venous tunnel formation using PTFE for partial anomalous pulmonary venous drainage and autopsy observations in cases 1 and 4 in SVC syndrome series gave us favorable findings. There was no neointimal over-proliferation to cause stenosis, though it was revealed that the intimal lining on this material was vulnerable and easily stripped. However, this disadvantage may not be a problem so long as PTFE is used in a venous system without considerable pulsatile How that creates a strong shear stress on lining intima and causes separation from conduit surface. From these considerations, we would prefer direct anastomosis of the right atrium to the pulmonary artery, but we dared to utilize conduits for the anastomosis in selected patients to expand the criteria vertically as well as horizontally. Concerning PTFE as conduit material, a careful long-term follow-up will be necessary for warranty of the distinct advantage of this material to bridge the right atrium and distal pulmonary artery. We have described some operative

methods and practical ways in detail hoping to be supported by larger clinical series. REFERENCES 1 Fontan F, Baudet E. Surgical repair of tricuspid atresia. Thorax 1971; 26:240-48 2 Marcelletti C, Mazzara E, Olthof H, Sebel PS, Duren DR, Losekoot TG, Becker AE. Fontans operation. An expanded horizon. J Thorac Cardiovasc Surg 1980; 80:764-69 3 Yacoub MH, Radley-Smith R. Use of a valved conduit from right atrium to pulmonary artery for "correction" of single ventricle. Circulation 1976; 54:Suppl 3:63-70 4 Bjork VO, Olin CL, Bjarke BB, Thoren CA. Right atrial-right ventricular anastomosis for correction of tricuspid atresia. J Thorac Cardiovasc Surg 1979; 77:452-58 5 Fiore AC, Peigh PS, Robinson RJ, Giant MD, King H, Brown JW: Valved and nonvalved ventricular-pulmonary arterial extracardiac conduits. J Thorac Cardiovasc Surg 1983; 86:490-97 6 Gale AW, Danielson GK, McGoon DC, Wallace RB, Mair DD. Fontan procedure for tricuspid atresia. Circulation 1980; 62:91-6 7 Doty DB, Marvin WJ, Lauer RM. Modified Fontan procedure. J Thorac Cardiovasc Surg 1981; 81:470-75 b Choussat A, Fontan F, Besse ~ Vallot F, Chouve A, Bricaud H. Selection criteria for Fontans procedure. In: Anderson RH, Shinebourne EA, eds. Paediatric cardiology. Edinburgh: Churchill Livingston, 1978:559-66 9 Shemin RJ, Merrill WH, pfeifer JS, Conkle DM, Morrow AG. Evaluation of right atrial-pulmonary artery conduits for tricuspid atresia. Experimental study. J Thorac Cardiovasc Surg 1979; 77:685-90 10 Matsuda H, Kawashima Y, Takano H, Miyamoto K, Morl 1: Experimental evaluation of atrial function in right atriumpulmonary artery conduit operation for tricuspid atresia. J Thorac Cardiovasc Surg 1981; 81:762-67 11 Serrato M, Miller RA, Tatooles C, Ardekani R: Hemodynamic evaluation of Fontan operation in tricuspid atresia. Circulation 1976; 54:SuppI3:99-101 12 Yacoub MH. Fontans operation-Are caval valves necessary? In: Anderson RH, Shinebourne EA, eds. Paediatric cardiology. Edinburgh. Churchill Livingstone, 1977:582-92 13 Nakazawa M, Satomi M, Okuda H, Nakae S, Imai Y, Koyanagi H, et al. An analysis of blood Bow pattern in the right heart after Fontan procedure. J Jpn Asoc Thorac Surg 1984; 32:338-48 14 Kreitmann ~ Bourlon F, Jourdan J, Dor V. Surgical treatment of primitive ventricle and complex congenital heart malformation with total exclusion of the right heart: Report of a case. J Thorac Cardiovasc Surg 1982; 84:150 15 Fiore AC, Brown jw Cromartie RS, Ofstein LC, Peigh PS, Sears NS, et al. Prosthetic replacement of the thoracic vena cava: An experimental study. J Thorac Cardiovasc Surg 1982; 84:560-68 16 Todd RS, Sive EB, Devore LR, Damese C, Howard JM. Replacement of segments of the venous system. Arch Surg 1963; 87:998-1002 17 Agarwal KC, Edwards WD, Feldt RH, Danielson GK, Puga FJ, McGoon DC. Clinicopathological correlates of obstructed rightsided porcine valved extracardiac conduits. J Thorac Cardiovasc Surg 1981; 81:591-601 18 Ben-Shachar G, NicoloffDM, Edwards JE. Separation ofneointima from Dacron graft causing obstruction. Case following Fontan procedure for tricuspid atresia. J Thorac Cardiovasc Surg 1981; 82:268-71 19 Brown JW, Halpin M~ Rescorla FJ, VanNatta B~ Fiore AC, Shipley GO, et al. Externally stented polytetrafluoroethylene valved conduits for right heart reconstruction: An experimental comparison with Dacron valved conduits. J Thorac Cardiovasc Surg 1985; 90:833-41 CHEST I 91 I 4 I APRIL. 1987

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