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Truncal valve repair: Initial experience with infants and children
Truncal Valve Repair: Initial Experience With Infants and Children Amir Elami, MD, Hillel Laks, MD, and Jeffrey M. Pearl, MD Division of Cardiothoracic Surgery, Department of Surgery, UCLA Medical Center, Los Angeles, California
The truncal valve regurgitation that frequently arises in patients with truncus arteriosus accounts for increased operative and late mortality. Five patients underwent truncal valve repair at UCLA Medical Center between August 1990 and September 1991. This group consisted of 2 infants who underwent complete repair and 3 who underwent valve repair together with right ventriclepulmonary artery conduit replacement. The techniques used for repair were individualized according to the specific valve morphology, and consisted of the suturing of partially developed commissures, suspension of the cusps, resection of redundant portions of the cusps,
annuloplasty at the commissures, and resection of excrescences on the surface of valve leaflets. In 1 infant who had a severely dysplastic truncal valve, stenosis and regurgitation recurred and progressed, and he died 4 months after truncal valve replacement. The remaining 4 patients, who were followed for from 8 to 21 months after repair, are in New York Heart Association class I, and have minimal or no aortic regurgitation. Except in patients with severely deformed and dysplastic valves, truncal valve repair can be an attractive and successful alternative to valve replacement. (Ann Thorac Surg 1994;57:397402)
T
repair remain scarce. We present our experience in 5 patients with the repair of an insufficient truncal valve as an alternative to valve replacement.
runcus arteriosus is an uncommon cardiac malformation that results from failed septation of the embryonic truncus and conus. The malformation consists of a single semilunar valve at the common outflow of both ventricles and a single arterial trunk that gives rise to the systemic, pulmonary, and coronary circulations. If there is no stenosis at the pulmonary artery ostia, which is uncommon, the pulmonary circuit is exposed to systemic pressure and high flow. The increased runoff from the truncal artery into the pulmonary circuit, concurrent with the decline in the pulmonary vascular resistance in early infancy, diminishes the diastolic pressure, thereby causing coronary hypoperfusion and ventricular dysfunction. Truncal valve regurgitation is encountered in up to 58% of the cases [I, 21, and, if it is present, further decreases in the diastolic and coronary perfusion pressures and increases in the ventricular volume load ensue. The added hemodynamic burden imposed by the truncal valve regurgitation worsens the preoperative congestive heart failure. It also creates a serious problem in terms of the surgical management [3] and increases the operative mortality [4]. If it is not dealt with during the initial truncus arteriosus repair, the attendant truncal valve insufficiency shortens the long-term survival rate [l]. Variable degrees of truncal valve incompetence may develop after truncus arteriosus repair, even if valve function is initially normal. Two recent reports have described successful truncal valve replacement in infants, using either a disc-valve prosthesis [5] or a valved homograft [6], but reports of Accepted for publication April 5, 1993. Address reprint requests to Dr Laks, Division of Cardiothoradc Surgery, UCLA Medical Center, CHS 62-182, 10833 LeConte Ave, Los Angeles, CA 90024.
0 1994 by The Society of Thoracic Surgeons
Material and Methods Between August 1990 and September 1991, 5 patients underwent truncal valve repair at the UCLA Medical Center. The preoperative clinical data, intraoperative findings, and postoperative outcome in these 5 patients are summarized in Table 1.Two patients (patients 2 and 4) were infants undergoing complete repair of truncus arteriosus. Three patients (patients 1, 3, and 5) had undergone their initial truncus arteriosus repair at 4 weeks, 4 months, and 15 months of age, respectively. In these 3 patients, repair of the incompetent truncal valve was performed in conjunction with right ventricle-pulmonary artery (RV-PA) conduit replacement. Cardiopulmonary bypass was established by aortic and dual venous caval cannulation. The total cardiopulmonary bypass time was 182 minutes (99 to 343 minutes), and the aortic cross-clamp time was 101 minutes (72 to 146 minutes).
Myocardial Protection Technique Our cardioplegia delivery technique has been described recently [7]. Briefly, in all cases, the aorta was clamped and an attempt was made to arrest the heart using antegrade (aortic root) blood cardioplegia. Ventricular distention was prevented by a left ventricular vent (DLP, Grand Rapids, MI), which was inserted via the right superior pulmonary vein. In all cases, the aortic root pressure obtained during the antegrade cardioplegia phase was inadequate, and therefore the retrograde (coronary sinus) administration of cardioplegia was begun 0003-4975/94/$7.00
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ELAMI ET AL TRUNCAL VALVE REPAIR
Ann Thorac Surg 1994;57397-402
Table I . S u m m a r y of the Clinical, lntraoperative, and Postoperative Data in 5 Patients Undergoing Truncal Valve Repair
Valve
Patient No.
Age
1
3.5 y
2
1 mo
Function Preop. Moderate regurgitation Moderate stenosis,
severe regurgitation
3
2y
4
4 mo
5
12 y
Mild to moderate
regurgitation Moderate stenosis and regurgitation
Mild to moderate
regurgitation
Aortic Root Cardioplegia Pressure (mm Hg)iFlgw (mL/min)
Truncal Valve
Morphology
Before Repair
After Repair
101450
80/150
No regurgitation
15/200
70/120
Progressive stenosis Late (4 mo)a and death from
4 cusps, mild
thickening 4 cusps, gelatinous
a
3 cusps, normal
This patient died after truncal valve replacement. =
Postop.
Outcome 14 mo, NYHA 1
regurgitation
nodules, excrescences 3 cusps, mild thickening 4 cusps, mild thickening
22 NYHA
Valve
Function
&
36/400
751160
No regurgitation
10 mo, NYHA 1
201400
70/150
Trivial regurgitation
2 mo, NYHA 1
301600
60/150
No regurgitation
1 mo, NYHA 1
5b/410+. 64‘
p < 0.0005.
71 2 31146
*7
p < 0.005.
New York Heart Association
immediately. Repeated doses of cold blood cardioplegia were administered every 20 minutes, alternating between antegrade (coronary ostia) and retrograde. After truncal valve repair and aortic closure, antegrade root cardioplegia was given to assess valve competence, measuring both the flow and pressure generated in the aortic root (see Table 1). Warm, amino acid-enriched blood-cardioplegia reperfusion was performed before the aortic cross-clamp was removed.
commissures using a horizontal mattress suture of 4-0 Prolene placed just below the crest of the commissures, and reinforced with pericardium (Fig 2).
Valve Repair Techniques In each case, an attempt was made to create a competent valve, yet avoid narrowing of the valve orifice. Repair consisted of different combinations of the following elements, depending on the individual valve morphology: suturing of partially developed commissures to obtain better support of the cusps, suspension of cusps to the annulus, resection of redundant portions of the cusps, resection of excrescences on the surface of the valve, and annuloplasty at the commissures to reduce annular size and accomplish good apposition of the leaflets in the center. Patient 1 who was 3% years old at the time of her RV-PA conduit replacement, had a four-cuspid truncal valve, with moderate regurgitation. The left cusp was a double cusp in which there was partial fusion of the commissure together with thickening and rubbing of the edges. The right cusp was prolapsed downward (Fig 1). Valve repair in this patient consisted first of creating a single left cusp using horizontal mattress sutures of 4-0 Somerville’ NJ) to ‘lose the partially the right and noncoronary commissure. CUSPS were suspended to the annulus using 5-0 Pro1ene reinforced with pericardial pledgets. This was followed by resection of the redundant portion of the right coronary cusp. Last, annuloplasty was performed at each of the
Fig 1. Truncal valve in patient 1 , showing a double left cusp with a raphe and prolapse of the right coronary cusp. The method of commissurd annuloplasty using a horizontal mattress suture, reinforced with pericardial pledgets, is demonstrated at the commissure between the right and the noncoronary cusps. Suspension of the right cusp to the annulus with a mattress suture is also depicted. (L = left; R = right.)
Ann Thorac Surg 1994;57397402
Fig 2. Truncal valve repair in patient 1 included suture of the partially developed commissure in the left cusp, suspension of the right and noncorona y commissures, resection of the prolapsing portion of the right coronay cusp, and an annuloplasty at each commissure. (L = left; R = right.)
Patient 2 was a 1-month-old male infant with severe congestive heart failure due to truncus arteriosus (type 1) that also involved severe truncal valve insufficiency and moderate stenosis. The truncal valve had four leaflets, but only two of the commissures were well developed. The valve was gelatinous and extremely deformed, with excrescences and prolapse of the leaflet tips (Fig 3). Repair of the valve consisted of suture of the poorly formed commissures followed by resection of the excrescences on the surface of the valve (Fig 4). An 8-mm Hegar dilator was passed easily through the valve, which appeared competent and better supported.
Fig 3 . Truncal valve in patient 2 . The valve had four leaflets but only two of the commissures were well developed. The cusp edges were thickened, with nodular excrescences, and the tips were prolapsed. (L = left; R = right.)
ELAMIETAL TRUNCAL VALVE REPAIR
399
Fig 4 . Truncal valve repair in patient 2 consisted of suture of the poorly developed commissures to make it a bicuspid valve and thinning of the leaflet edges to improve pliability. (L = left; R = right.)
Patient 3 was 2 years old when he underwent replacement of his obstructed RV-PA homograft conduit. The truncal valve had three leaflets, with mild thickening and prolapse of the right leaflet. Regurgitation was mild to moderate. Valve competence was accomplished by performing annuloplasty at each of the commissures and by shortening and suspending the prolapsing leaflet. Patient 4 was 4 months old at the time of his truncus arteriosus (type 1) repair. Postoperatively he had significant congestive heart failure resulting from moderate truncal valve stenosis and regurgitation, and reoperation was necessary to achieve valve repair. The valve in this patient had four mildly dysplastic and thickened leaflets. Repair consisted of suturing the two anterior leaflets together to reinforce each other, as these were the most poorly supported. Commissural annuloplasty was also performed. The valve orifice was noted to be adequate. In patient 5 , a 12-year-old boy, conduit stenosis and mild to moderate truncal valve regurgitation developed 11 years after initial repair performed when he was 15 months old. At reoperation, the valve was noted to have three leaflets with prolapse of a large left cusp and annular dilatation. The left cusp was suspended to the adjacent annulus using 4-0 polypropylene sutures reinforced with pericardial pledgets. An annuloplasty was performed in the commissure between the left and right cusp, and also between the noncoronary cusp and the right cusp. After termination of the cardiopulmonary bypass, all patients underwent epicardial or transesophageal colorflow Doppler echocardiography to assess valve competence. The simultaneous left ventricular and aortic root pressures were measured to detect truncal (aortic) valve gradients.
400
ELAMI ET AL TRUNCAL VALVE REPAIR
The most recent follow-up examination and transthoracic echocardiography findings were regarded as the late results. The statistical significance of the difference between the prerepair and postrepair antegrade cardioplegia flow and pressure was determined by a paired t test (Statview 11, Macintosh IIsi).
Results All 5 patients in this series survived repair and were discharged from the hospital. Infusion of antegrade cardioplega was used to assess valve repair intraoperatively after aortic closure. The mean pressure of 71 ? 3 mm Hg generated in the aortic root after valve repair was significantly higher ( p < 0.0005) than the 22 f 5 mm Hg noted before repair (see Table 1). This higher pressure was achieved at a mean flow rate of 146 ? 7 mL/min, which was significantly lower ( p < 0.005) than the flow rate of 410 ? 64 mL/min used when trying to induce cardioplegia before the repair. Intraoperative echocardiography was performed once cardiopulmonary bypass was discontinued. The transesophageal echocardiogram in patient 1 showed only mild aortic regurgitation, and no gradient was measured across the aortic valve. An epicardial echocardiogram in patient 2 revealed minimal aortic regurgitation and a mild gradient (5 to 10 mm Hg) across the aortic valve. The ejection fraction in this patient was estimated to be 30%. In patients 3, 4, and 5, transesophageal echocardiography showed only trivial or no aortic regurgitation. Patient 2’s sternum was left open at the conclusion of the procedure, because of the large size of his heart and the low ejection fraction while on inotropic support. The chest was closed 5 days later, at which time his ventricular function was improved and his need for inotropic support had gradually diminished. Recurrent episodes of hypocalcemia, which may have been related to the DiGeorge syndrome, and Enterobucter line sepsis complicated his postoperative course. An echocardiogram obtained just before discharge, on postoperative day 42, estimated the ejection fraction to be 60%, with mild aortic regurgitation and stenosis. The postoperative course in the remaining 4 patients was uneventful and they left the hospital between 6 to 8 days postoperatively. Serial echocardiograms obtained in patient 2 after discharge revealed progressive thickening of the truncal valve, with increasing stenosis and regurgitation. Four months postoperatively, moderate truncal valve stenosis and regurgitation had developed, along with a dilated and poorly contracting left ventricle. Reoperation for truncal valve replacement using a 12-mm porcine valve was undertaken 3 months later. The patient’s ventricular function was severely depressed, however, and this did not permit weaning from cardiopulmonary bypass. The patient was placed on extracorporeal membrane oxygenator support and died 6 days later, 2 hours after the discontinuation of oxygenator support. At last follow-up, the 4 survivors were all in New York Heart Association functional class I. Patient 1 has a grade
Ann Thorac Surg 1994;57397402
2/6 diastolic murmur with a systemic blood pressure of 110/80 mm Hg and only mild aortic regurgitation shown by echocardiography 21 months postoperatively. Patients 3 and 5, at 18 and 8 months postoperatively, respectively, have no aortic regurgitation based on the echocardiography findings, while patient 4 has trivial regurgitation 9 months after repair.
Comment The truncal valve is variable in terms of both the number and appearance of its cusps. Among 536 valves assessed in ten investigations, 3 (0.5%)were unicommissural, 59 (11%)were bicuspid, 356 (66.4%) were tricuspid, 116 (21.6%)were quadricuspid, and 2 (0.4%)were pentacuspid [8-171. The valve leaflets were normal in 19% to 28% of the cases [15, 171, and either thickened or dysplastic in the remainder. Uniform or nodular thickening and unequal cusp size are characteristic of incompetent truncal valves [9, 13, 161. The functional state of the truncal valve cannot be determined with confidence in autopsy specimens. In clinical studies, however, moderate to severe truncal valve regurgitation is found in 36% to 58% of the patients with truncus arteriosus [I, 21. Throughout the evolution of repair procedures for truncus arteriosus, concerns about myocardial protection determined the management of truncal valve regurgitation. De Leva1 and colleagues [3], who used intermittent release of the aortic clamp to allow coronary perfusion, recommended temporary cusp approximation as a simple technique for managing truncal valve regurgitation. They suggested that, in all but the most severe instances of truncal valve regurgitation, persistence of the regurgitation postoperatively may be preferable to replacing the valve. Ebert and associates [4] developed a perfusion method for repair of truncus arteriosus that involved a very short aortic cross-clamp time and without cardioplegia. The cross-clamp period is used for excision of the pulmonary trunk or arteries and closure of the defect in the aorta. The heart is restarted after aortic declamping, and this minimizes ventricular distention stemming from truncal valve insufficiency. In their report, eight of the 11 operative deaths occurred in patients with significant truncal valve insufficiency. They recommended replacement of the abnormal truncal valve to prevent both its immediate and long-term detrimental sequelae [l, 41. Retrograde coronary sinus cardioplegia, which has recently been applied on the pediatric population [7], allows for a longer ischemic arrest time and thus the correction of all associated abnormalities. This offers a distinct advantage over antegrade techniques when there is aortic (or truncal) valve regurgitation, and when the aortic root is open. When truncal valve repair is being considered as an alternative to valve replacement, the mechanism of regurgitation should be identified. Truncal valve regurgitation generally results from cusp prolapse and annular dilatation [lo, 141. Nodular thickening of the free edge and fibrotic pads along the cusp surfaces are probably the result of chronic valve regurgitation (161. Although it is
Ann Thorac Surg 1994;57397402
difficult to derive information from anatomic studies for deciding the nature of surgical management, we believe that a substantial number of incompetent truncal valves can be repaired rather than left untreated or replaced. Truncal valve repair should include resection of valvar excrescences and redundant lips, as well as the suspension of prolapsed cusps to the annulus. Better support can be obtained by suturing underdeveloped commissures and performing annuloplasty. To ensure competency, the free edges of the cusps (lunulae) should be in a state of coaptation when the valve is closed. Annular dilatation is responsible for some degree of cusp prolapse and failure of the cusps to oppose each other in the center. By performing annuloplasty at the commissures, but below the plane of the free edges, more of the cusp surfaces are displaced inwardly, with concomitant reduction of annular circumference. This promotes better coaptation and support. The contribution of this type of annuloplasty, originally described by Cabrol and associates [18], to the success of aortic valve repair has recently been documented [19, 201. To increase valvar pliability and prevent stenosis, the thickened leaflets should be thinned out and nodules should be resected. The repair is tested immediately by the infusion of cardioplegia into the aortic root. An adequate pressure (70 to 80 mm Hg) should be obtained without ventricular distention and without a substantial increase in the amount of blood vented from the ventricular cavity. Valve function should be evaluated again after cardiopulmonary bypass is discontinued using epicardial echocardiography in infants and transesophageal echocardiography in older children. The techniques outlined here are applicable to very young infants and neonates as well as older infants and children, as long as the valvular anatomy is suitable for repair. We do not replace or repair the truncal valve at the time of truncus arteriosus repair when only mild or moderate regurgitation exists preoperatively. Many of these valves become more competent once the volume load is relieved. Because most of the neonates and young infants go on to require conduit replacement within a few years, truncal valve repair can be performed more safely at that time if the valve is still regurgitant. Infants with severe truncal valve regurgitation or stenosis, or both, should undergo either valve repair or replacement at the time of definitive repair, however. Based on our current experience, the durability of truncal valve repair cannot be predicted. The short-term results (8 t o 21 months) in 4 of our 5 patients have, however, proved satisfactory. Further growth may allow the use of an adult-sized substitute for the truncal valve, should the later need for replacement arise. Truncal valve repair may not be superior to valve replacement if the valve is severely thickened and deformed, as seen in patient 2, whose truncal valve stenosis progressed and regurgitation recurred, causing left ventricular volume overload and failure. In view of the risk of thromboembolic events and anticoagulant-related complications in the pediatric age group, and the relatively complex reoperation required
ELAMI ET AL TRUNCAL VALVE REPAIR
401
for valve or homograft replacement, an attempt at repair of the truncal valve is warranted, even when dealing with somewhat irregularly thickened and unbalanced valves.
References 1. Di Donato RM, Fyfe DA, Puga FJ, et al. Fifteen-year experience with surgcal repair of truncus arteriosus. J Thorac Cardiovasc Surg 1985;89:414-22. 2. Gelband H, Van Meter S, Gersony WM. Truncal valve abnormalities in infants with persistent truncus arteriosus: a clinicopathologic study. Circulation 1972;45:397403. 3. De Leva1 MR, McGoon DC, Wallace RB, Danielson GK, Mair DD. Management of truncal valvular regurgitation. Ann Surg 1974;180:427-32. 4. Ebert PA, Turley K, Stanger P, Hoffman JIE, Heymann MA, Rudolph AM. Surgical treatment of truncus arteriosus in the first 6 months of life. Ann Surg 1984;200:451-6. 5. Bove EL, Beekman RH, Snider R, et al. Repair of truncus arteriosus in the neonate and young infant. Ann Thorac Surg 1989;47499-506. 6. Elkins RC, Steinberg JB, Razook JD, Ward KE, Overholt ED, Thompson WE Jr. Correction of truncus arteriosus with truncal valvar stenosis or insufficiency using two homografts. Ann Thorac Surg 1990;50:728-33. 7. Drinkwater DC Jr, Cushen CK, Laks H, Buckberg GD. The use of combined antegrade-retrograde blood cardioplegia in pediatric open heart surgery: the UCLA experience. J Thorac Cardiovasc Surg 1992;104:1349-55. 8. Van Praagh R, Van Praagh S. The anatomy of common aorticopulmonary trunk (truncus arteriosus communis) and its embriologic implications: a study of 57 necropsy cases. Am J Cardiol 1965;16:40&25. 9. Becker AE, Becker MJ, Edwards JE. Pathology of the semilunar valve in persistent truncus arteriosus. J Thorac Cardiovasc Surg 1971;62:16-26. 10. Bharati S, McAllister HA Jr, Rosenquist GC, et al. The surgical anatomy of truncus arteriosus communis. J Thorac Cardiovasc Surg 1974;67501-10. 11. Thiene G, Bortolotti U, Gallucci V, et al. Anatomical study of truncus arteriosus communis with embryological and surgical considerations. Br Heart J 1976;38:1109-23. 12. Shrivastava S, Edwards JE. Coronary arterial origin in persistent truncus arteriosus. Circulation 1977;55:5514. 13. Crupi G, Macartny FJ, Anderson RH. Persistent truncus arteriosus: a study of 66 autopsy cases with special reference to definition and morphogenesis. Am J Cardiol 1977;40: 569-78. 14. Anderson KR, McGoon DC, Lie JT. Surgical significance of the coronary arterial anatomy in truncus arteriosus communis. Am J Cardiol 1978;41:76-81. 15. Butto F, Lucas RV Jr, Edwards JE. Persistent truncus arteriosus: pathologic anatomy in 54 cases. Pediatr Cardiol 1986; 7:95101. 16. Fuglestad SJ, Puga FJ, Danielson GK, Edwards ED. Surgical pathology of the truncal valve: a study of 12 cases. Am J Cardiovasc Pathol 1988;2:3947. 17. Suzuki A, Yen Ho S, Anderson RH, Deanfield JE. Coronary arterial and sinusal anatomy in hearts with a common arterial trunk. Ann Thorac Surg 1989;48:792-7. 18. Cabrol C, Guiraudon G, Bertrand M. Le traitment de l'insuffisance aortique par l'annuloplastie aortique. Arch Ma1 Coeur 1966;59:1305-12. 19. Duran C, Kumar N, Gometza B, A1 Halees Z. Indications and limitations of aortic valve reconstruction. Ann Thorac Surg 1991;52:447-54. 20. Cosgrove DM, Rosenkraz ER, Hendren WG, Barlett JC, Stewart WJ. Valvuloplasty for aortic insufficiency. J Thorac Cardivasc Surg 1991;102:571-7.
The truncal valve regurgitation that frequently arises in patients with truncus arteriosus accounts for increased operative and late mortality. Five patients underwent truncal valve repair at UCLA Medical Center between August 1990 and September 1991. This group consisted of 2 infants who underwent complete repair and 3 who underwent valve repair together with right ventriclepulmonary artery conduit replacement. The techniques used for repair were individualized according to the specific valve morphology, and consisted of the suturing of partially developed commissures, suspension of the cusps, resection of redundant portions of the cusps,
annuloplasty at the commissures, and resection of excrescences on the surface of valve leaflets. In 1 infant who had a severely dysplastic truncal valve, stenosis and regurgitation recurred and progressed, and he died 4 months after truncal valve replacement. The remaining 4 patients, who were followed for from 8 to 21 months after repair, are in New York Heart Association class I, and have minimal or no aortic regurgitation. Except in patients with severely deformed and dysplastic valves, truncal valve repair can be an attractive and successful alternative to valve replacement. (Ann Thorac Surg 1994;57:397402)
T
repair remain scarce. We present our experience in 5 patients with the repair of an insufficient truncal valve as an alternative to valve replacement.
runcus arteriosus is an uncommon cardiac malformation that results from failed septation of the embryonic truncus and conus. The malformation consists of a single semilunar valve at the common outflow of both ventricles and a single arterial trunk that gives rise to the systemic, pulmonary, and coronary circulations. If there is no stenosis at the pulmonary artery ostia, which is uncommon, the pulmonary circuit is exposed to systemic pressure and high flow. The increased runoff from the truncal artery into the pulmonary circuit, concurrent with the decline in the pulmonary vascular resistance in early infancy, diminishes the diastolic pressure, thereby causing coronary hypoperfusion and ventricular dysfunction. Truncal valve regurgitation is encountered in up to 58% of the cases [I, 21, and, if it is present, further decreases in the diastolic and coronary perfusion pressures and increases in the ventricular volume load ensue. The added hemodynamic burden imposed by the truncal valve regurgitation worsens the preoperative congestive heart failure. It also creates a serious problem in terms of the surgical management [3] and increases the operative mortality [4]. If it is not dealt with during the initial truncus arteriosus repair, the attendant truncal valve insufficiency shortens the long-term survival rate [l]. Variable degrees of truncal valve incompetence may develop after truncus arteriosus repair, even if valve function is initially normal. Two recent reports have described successful truncal valve replacement in infants, using either a disc-valve prosthesis [5] or a valved homograft [6], but reports of Accepted for publication April 5, 1993. Address reprint requests to Dr Laks, Division of Cardiothoradc Surgery, UCLA Medical Center, CHS 62-182, 10833 LeConte Ave, Los Angeles, CA 90024.
0 1994 by The Society of Thoracic Surgeons
Material and Methods Between August 1990 and September 1991, 5 patients underwent truncal valve repair at the UCLA Medical Center. The preoperative clinical data, intraoperative findings, and postoperative outcome in these 5 patients are summarized in Table 1.Two patients (patients 2 and 4) were infants undergoing complete repair of truncus arteriosus. Three patients (patients 1, 3, and 5) had undergone their initial truncus arteriosus repair at 4 weeks, 4 months, and 15 months of age, respectively. In these 3 patients, repair of the incompetent truncal valve was performed in conjunction with right ventricle-pulmonary artery (RV-PA) conduit replacement. Cardiopulmonary bypass was established by aortic and dual venous caval cannulation. The total cardiopulmonary bypass time was 182 minutes (99 to 343 minutes), and the aortic cross-clamp time was 101 minutes (72 to 146 minutes).
Myocardial Protection Technique Our cardioplegia delivery technique has been described recently [7]. Briefly, in all cases, the aorta was clamped and an attempt was made to arrest the heart using antegrade (aortic root) blood cardioplegia. Ventricular distention was prevented by a left ventricular vent (DLP, Grand Rapids, MI), which was inserted via the right superior pulmonary vein. In all cases, the aortic root pressure obtained during the antegrade cardioplegia phase was inadequate, and therefore the retrograde (coronary sinus) administration of cardioplegia was begun 0003-4975/94/$7.00
398
ELAMI ET AL TRUNCAL VALVE REPAIR
Ann Thorac Surg 1994;57397-402
Table I . S u m m a r y of the Clinical, lntraoperative, and Postoperative Data in 5 Patients Undergoing Truncal Valve Repair
Valve
Patient No.
Age
1
3.5 y
2
1 mo
Function Preop. Moderate regurgitation Moderate stenosis,
severe regurgitation
3
2y
4
4 mo
5
12 y
Mild to moderate
regurgitation Moderate stenosis and regurgitation
Mild to moderate
regurgitation
Aortic Root Cardioplegia Pressure (mm Hg)iFlgw (mL/min)
Truncal Valve
Morphology
Before Repair
After Repair
101450
80/150
No regurgitation
15/200
70/120
Progressive stenosis Late (4 mo)a and death from
4 cusps, mild
thickening 4 cusps, gelatinous
a
3 cusps, normal
This patient died after truncal valve replacement. =
Postop.
Outcome 14 mo, NYHA 1
regurgitation
nodules, excrescences 3 cusps, mild thickening 4 cusps, mild thickening
22 NYHA
Valve
Function
&
36/400
751160
No regurgitation
10 mo, NYHA 1
201400
70/150
Trivial regurgitation
2 mo, NYHA 1
301600
60/150
No regurgitation
1 mo, NYHA 1
5b/410+. 64‘
p < 0.0005.
71 2 31146
*7
p < 0.005.
New York Heart Association
immediately. Repeated doses of cold blood cardioplegia were administered every 20 minutes, alternating between antegrade (coronary ostia) and retrograde. After truncal valve repair and aortic closure, antegrade root cardioplegia was given to assess valve competence, measuring both the flow and pressure generated in the aortic root (see Table 1). Warm, amino acid-enriched blood-cardioplegia reperfusion was performed before the aortic cross-clamp was removed.
commissures using a horizontal mattress suture of 4-0 Prolene placed just below the crest of the commissures, and reinforced with pericardium (Fig 2).
Valve Repair Techniques In each case, an attempt was made to create a competent valve, yet avoid narrowing of the valve orifice. Repair consisted of different combinations of the following elements, depending on the individual valve morphology: suturing of partially developed commissures to obtain better support of the cusps, suspension of cusps to the annulus, resection of redundant portions of the cusps, resection of excrescences on the surface of the valve, and annuloplasty at the commissures to reduce annular size and accomplish good apposition of the leaflets in the center. Patient 1 who was 3% years old at the time of her RV-PA conduit replacement, had a four-cuspid truncal valve, with moderate regurgitation. The left cusp was a double cusp in which there was partial fusion of the commissure together with thickening and rubbing of the edges. The right cusp was prolapsed downward (Fig 1). Valve repair in this patient consisted first of creating a single left cusp using horizontal mattress sutures of 4-0 Somerville’ NJ) to ‘lose the partially the right and noncoronary commissure. CUSPS were suspended to the annulus using 5-0 Pro1ene reinforced with pericardial pledgets. This was followed by resection of the redundant portion of the right coronary cusp. Last, annuloplasty was performed at each of the
Fig 1. Truncal valve in patient 1 , showing a double left cusp with a raphe and prolapse of the right coronary cusp. The method of commissurd annuloplasty using a horizontal mattress suture, reinforced with pericardial pledgets, is demonstrated at the commissure between the right and the noncoronary cusps. Suspension of the right cusp to the annulus with a mattress suture is also depicted. (L = left; R = right.)
Ann Thorac Surg 1994;57397402
Fig 2. Truncal valve repair in patient 1 included suture of the partially developed commissure in the left cusp, suspension of the right and noncorona y commissures, resection of the prolapsing portion of the right coronay cusp, and an annuloplasty at each commissure. (L = left; R = right.)
Patient 2 was a 1-month-old male infant with severe congestive heart failure due to truncus arteriosus (type 1) that also involved severe truncal valve insufficiency and moderate stenosis. The truncal valve had four leaflets, but only two of the commissures were well developed. The valve was gelatinous and extremely deformed, with excrescences and prolapse of the leaflet tips (Fig 3). Repair of the valve consisted of suture of the poorly formed commissures followed by resection of the excrescences on the surface of the valve (Fig 4). An 8-mm Hegar dilator was passed easily through the valve, which appeared competent and better supported.
Fig 3 . Truncal valve in patient 2 . The valve had four leaflets but only two of the commissures were well developed. The cusp edges were thickened, with nodular excrescences, and the tips were prolapsed. (L = left; R = right.)
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Fig 4 . Truncal valve repair in patient 2 consisted of suture of the poorly developed commissures to make it a bicuspid valve and thinning of the leaflet edges to improve pliability. (L = left; R = right.)
Patient 3 was 2 years old when he underwent replacement of his obstructed RV-PA homograft conduit. The truncal valve had three leaflets, with mild thickening and prolapse of the right leaflet. Regurgitation was mild to moderate. Valve competence was accomplished by performing annuloplasty at each of the commissures and by shortening and suspending the prolapsing leaflet. Patient 4 was 4 months old at the time of his truncus arteriosus (type 1) repair. Postoperatively he had significant congestive heart failure resulting from moderate truncal valve stenosis and regurgitation, and reoperation was necessary to achieve valve repair. The valve in this patient had four mildly dysplastic and thickened leaflets. Repair consisted of suturing the two anterior leaflets together to reinforce each other, as these were the most poorly supported. Commissural annuloplasty was also performed. The valve orifice was noted to be adequate. In patient 5 , a 12-year-old boy, conduit stenosis and mild to moderate truncal valve regurgitation developed 11 years after initial repair performed when he was 15 months old. At reoperation, the valve was noted to have three leaflets with prolapse of a large left cusp and annular dilatation. The left cusp was suspended to the adjacent annulus using 4-0 polypropylene sutures reinforced with pericardial pledgets. An annuloplasty was performed in the commissure between the left and right cusp, and also between the noncoronary cusp and the right cusp. After termination of the cardiopulmonary bypass, all patients underwent epicardial or transesophageal colorflow Doppler echocardiography to assess valve competence. The simultaneous left ventricular and aortic root pressures were measured to detect truncal (aortic) valve gradients.
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The most recent follow-up examination and transthoracic echocardiography findings were regarded as the late results. The statistical significance of the difference between the prerepair and postrepair antegrade cardioplegia flow and pressure was determined by a paired t test (Statview 11, Macintosh IIsi).
Results All 5 patients in this series survived repair and were discharged from the hospital. Infusion of antegrade cardioplega was used to assess valve repair intraoperatively after aortic closure. The mean pressure of 71 ? 3 mm Hg generated in the aortic root after valve repair was significantly higher ( p < 0.0005) than the 22 f 5 mm Hg noted before repair (see Table 1). This higher pressure was achieved at a mean flow rate of 146 ? 7 mL/min, which was significantly lower ( p < 0.005) than the flow rate of 410 ? 64 mL/min used when trying to induce cardioplegia before the repair. Intraoperative echocardiography was performed once cardiopulmonary bypass was discontinued. The transesophageal echocardiogram in patient 1 showed only mild aortic regurgitation, and no gradient was measured across the aortic valve. An epicardial echocardiogram in patient 2 revealed minimal aortic regurgitation and a mild gradient (5 to 10 mm Hg) across the aortic valve. The ejection fraction in this patient was estimated to be 30%. In patients 3, 4, and 5, transesophageal echocardiography showed only trivial or no aortic regurgitation. Patient 2’s sternum was left open at the conclusion of the procedure, because of the large size of his heart and the low ejection fraction while on inotropic support. The chest was closed 5 days later, at which time his ventricular function was improved and his need for inotropic support had gradually diminished. Recurrent episodes of hypocalcemia, which may have been related to the DiGeorge syndrome, and Enterobucter line sepsis complicated his postoperative course. An echocardiogram obtained just before discharge, on postoperative day 42, estimated the ejection fraction to be 60%, with mild aortic regurgitation and stenosis. The postoperative course in the remaining 4 patients was uneventful and they left the hospital between 6 to 8 days postoperatively. Serial echocardiograms obtained in patient 2 after discharge revealed progressive thickening of the truncal valve, with increasing stenosis and regurgitation. Four months postoperatively, moderate truncal valve stenosis and regurgitation had developed, along with a dilated and poorly contracting left ventricle. Reoperation for truncal valve replacement using a 12-mm porcine valve was undertaken 3 months later. The patient’s ventricular function was severely depressed, however, and this did not permit weaning from cardiopulmonary bypass. The patient was placed on extracorporeal membrane oxygenator support and died 6 days later, 2 hours after the discontinuation of oxygenator support. At last follow-up, the 4 survivors were all in New York Heart Association functional class I. Patient 1 has a grade
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2/6 diastolic murmur with a systemic blood pressure of 110/80 mm Hg and only mild aortic regurgitation shown by echocardiography 21 months postoperatively. Patients 3 and 5, at 18 and 8 months postoperatively, respectively, have no aortic regurgitation based on the echocardiography findings, while patient 4 has trivial regurgitation 9 months after repair.
Comment The truncal valve is variable in terms of both the number and appearance of its cusps. Among 536 valves assessed in ten investigations, 3 (0.5%)were unicommissural, 59 (11%)were bicuspid, 356 (66.4%) were tricuspid, 116 (21.6%)were quadricuspid, and 2 (0.4%)were pentacuspid [8-171. The valve leaflets were normal in 19% to 28% of the cases [15, 171, and either thickened or dysplastic in the remainder. Uniform or nodular thickening and unequal cusp size are characteristic of incompetent truncal valves [9, 13, 161. The functional state of the truncal valve cannot be determined with confidence in autopsy specimens. In clinical studies, however, moderate to severe truncal valve regurgitation is found in 36% to 58% of the patients with truncus arteriosus [I, 21. Throughout the evolution of repair procedures for truncus arteriosus, concerns about myocardial protection determined the management of truncal valve regurgitation. De Leva1 and colleagues [3], who used intermittent release of the aortic clamp to allow coronary perfusion, recommended temporary cusp approximation as a simple technique for managing truncal valve regurgitation. They suggested that, in all but the most severe instances of truncal valve regurgitation, persistence of the regurgitation postoperatively may be preferable to replacing the valve. Ebert and associates [4] developed a perfusion method for repair of truncus arteriosus that involved a very short aortic cross-clamp time and without cardioplegia. The cross-clamp period is used for excision of the pulmonary trunk or arteries and closure of the defect in the aorta. The heart is restarted after aortic declamping, and this minimizes ventricular distention stemming from truncal valve insufficiency. In their report, eight of the 11 operative deaths occurred in patients with significant truncal valve insufficiency. They recommended replacement of the abnormal truncal valve to prevent both its immediate and long-term detrimental sequelae [l, 41. Retrograde coronary sinus cardioplegia, which has recently been applied on the pediatric population [7], allows for a longer ischemic arrest time and thus the correction of all associated abnormalities. This offers a distinct advantage over antegrade techniques when there is aortic (or truncal) valve regurgitation, and when the aortic root is open. When truncal valve repair is being considered as an alternative to valve replacement, the mechanism of regurgitation should be identified. Truncal valve regurgitation generally results from cusp prolapse and annular dilatation [lo, 141. Nodular thickening of the free edge and fibrotic pads along the cusp surfaces are probably the result of chronic valve regurgitation (161. Although it is
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difficult to derive information from anatomic studies for deciding the nature of surgical management, we believe that a substantial number of incompetent truncal valves can be repaired rather than left untreated or replaced. Truncal valve repair should include resection of valvar excrescences and redundant lips, as well as the suspension of prolapsed cusps to the annulus. Better support can be obtained by suturing underdeveloped commissures and performing annuloplasty. To ensure competency, the free edges of the cusps (lunulae) should be in a state of coaptation when the valve is closed. Annular dilatation is responsible for some degree of cusp prolapse and failure of the cusps to oppose each other in the center. By performing annuloplasty at the commissures, but below the plane of the free edges, more of the cusp surfaces are displaced inwardly, with concomitant reduction of annular circumference. This promotes better coaptation and support. The contribution of this type of annuloplasty, originally described by Cabrol and associates [18], to the success of aortic valve repair has recently been documented [19, 201. To increase valvar pliability and prevent stenosis, the thickened leaflets should be thinned out and nodules should be resected. The repair is tested immediately by the infusion of cardioplegia into the aortic root. An adequate pressure (70 to 80 mm Hg) should be obtained without ventricular distention and without a substantial increase in the amount of blood vented from the ventricular cavity. Valve function should be evaluated again after cardiopulmonary bypass is discontinued using epicardial echocardiography in infants and transesophageal echocardiography in older children. The techniques outlined here are applicable to very young infants and neonates as well as older infants and children, as long as the valvular anatomy is suitable for repair. We do not replace or repair the truncal valve at the time of truncus arteriosus repair when only mild or moderate regurgitation exists preoperatively. Many of these valves become more competent once the volume load is relieved. Because most of the neonates and young infants go on to require conduit replacement within a few years, truncal valve repair can be performed more safely at that time if the valve is still regurgitant. Infants with severe truncal valve regurgitation or stenosis, or both, should undergo either valve repair or replacement at the time of definitive repair, however. Based on our current experience, the durability of truncal valve repair cannot be predicted. The short-term results (8 t o 21 months) in 4 of our 5 patients have, however, proved satisfactory. Further growth may allow the use of an adult-sized substitute for the truncal valve, should the later need for replacement arise. Truncal valve repair may not be superior to valve replacement if the valve is severely thickened and deformed, as seen in patient 2, whose truncal valve stenosis progressed and regurgitation recurred, causing left ventricular volume overload and failure. In view of the risk of thromboembolic events and anticoagulant-related complications in the pediatric age group, and the relatively complex reoperation required
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for valve or homograft replacement, an attempt at repair of the truncal valve is warranted, even when dealing with somewhat irregularly thickened and unbalanced valves.
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