- Email: [email protected]
Aortic valve repair
Aortic Valve Repair Carlos M.G. Duran, MD, FWD Department of Cardiovascular Diseases, Ring Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
T he positive results achieved with
mitral valve repair encouraged us to rediscover and apply old and often forgotten techniques of aortic valve reconstruction. The benefits and limitation of these techniques have been established over a period of 20 years. Three different techniques of aortic valve reconstruction are used, according to the amount and quality of cusp tissue. One, in patients with enough tissue, “repair” techniques such as commissurotomy, free edge unrolling or shaving, resuspension or annuloplasty can be applied. Two, patients with cusp retraction and severe free edge thickening undergo triple cusp extension with pericardium. Three, patients with fibrosed or even calcified leaflets but a good annulus undergo valve reconstruction with glutaraldehyde-treated autologous pericardium. Since August 1988, 280 patients have undergone aortic valve reconstruction. Repairs were carried out in 202 patients. Hospital mortality was 4% and late mortality was 4.1%. Bovine pericardium was used in 27 patients and reconstruction with autologous pericardium was carried out in 51 patients. There was no hospital mortality in the last two groups; late mortality was 3.8% and the incidence of reoperation was 5.1%. Patients undergoing isolated aortic surgery had no thromboembolic events. These techniques are limited by the amount of cusp tissue for repair and by the still unknown durability of the pericardium for reconstruction. (Asia Pacific J Thorac Cardiovasc Surg 1994;3(2):64-68) Introduction
that aortic reconstruction selected patients.
Reconstructive surgery of the aortic valve has received less attention than the repair of the atrioventricular valves. This is probably due to the better results achieved with aortic valve replacement and the precise geometry needed to achieve competence. The history of aortic valve repair, however, is as long as that of mitral valve repair.
can be safely undertaken in
Surgical Principles Aortic valve reconstruction is not an alternative to replacement. It should rather be considered as part of the surgical armamentarium. As with mitral valve repair, detailed analysis of the valve lesions, both echocardiographically and directly, is essential.
The first aortic commissurotomy was performed by Tuffier 1 in 1913, well before a similar operation on the mitral valve was successfully carried out *. Before the advent of cardiopulmonary bypass, aortic regurgitation was treated with bicuspidisation 3*4 and circumclusion 5*6. Once open heart surgery became an option, a number of reconstructive techniques were explored, including open commissurotomy 7,8, annuloplasty g and cusp extension lo,“.
The surgeon must change his or her attitude so that every aortic valve is always observed carefully even if, as in most cases, it is going to be replaced. Repeated examination should eventually lead the surgeon to consider reconstruction rather than replacement. The actual reconstructive techniques fall into three distinct categories. Those patients judged to have enough valvular tissue undergo a variety of manoeuvres directed towards achieving competence without the use of extravalvular tissue. These techniques, grouped under the heading of “repair”, should be taken as a whole since usually each individual technique only achieves partial improvement and requires reinforcement by other repair techniques i3. In the presence of severe cusp retraction or calcification, “cusp extension” with extravalvular tissue is necessary, provided the base is free and mobile. The positive experience obtained with this technique and the detection of residual gradients in those cases with a thick cusp remnant encouraged us to develop a third category of reconstruction, resulting in total valve replacement with freehand autologous pericardium.
These techniques, because of their rather unpredictable and often poor results, were soon displaced by the far more reliable new prostheses. Nowadays, the vast majority of surgeons treat all aortic lesions by replacement, with the exception of congenital stenotic lesions in the very young and regurgitations secondary to septal defects. Faced with patients who had undergone a successful mitral valve repair and frequently suffered from an associated aortic lesion, we were encouraged to reexplore the possibilities of aortic valve repair. After 20 years of experience using this approach 12, we consider
64
Asia Pacific
J Thorac
Cardiovasc
Surg 1994;3(2) Aortic
DUKUl valve repair
Fig. 1. Aortic valve commissurotomy.
Fig. 2. Unrolling the free edge of the aortic valve,
As with mitral valve repair, a method to evaluate the results of the reconstruction intraoperatively is needed. Direct visual observation of the reconstructed aortic valve through the open aortotomy is totally unreliable. We have used 2 different methods. The first is the direct observation of the aortic valve through the 30-degree optics of a cystoscope introduced through the closed aortotomy while the root is pressurised with clear fluid and the aorta is still cross clamped 14.The second method involves measurement of the return through the left ventricular vent in relation to the pump output. Return percentages below 8-10% have been shown to correspond to non-significant residual regurgitation. Although experience and the regular use of transoesophageal two-dimensional colour Doppler echocardiography have rendered these 2 methods somewhat obsolete, they still have considerable selfteaching value.
exposure. Closure of this aortotomy after repair is easy because of the absence of a rigid prosthesis. Closure is carried out with 2 over-and-over 4/O polypropylene sutures started at each end of the incision and tied to each other at the most anterior part of the aortotomy. Root suction is applied before unclamping the aorta and maintained for several minutes after weaning from bypass. Repair Techniques These “repair” techniques must be applied according to the surgical fmdings and are limited by the amount and quality of valve tissue available. The following manoeuvres are used, most often in combination: 1) commissurotomy, always performed in the presence of even minimal fusion in order to maximise cusp mobility. Often the commissurotomy has to be performed across thickened and even calcified tissue. Shaving of the excess tissue from both cusps, at this level if possible, renders them mobile (Fig. 1). 2) free edge unrolling of each leaflet which increases the cuspal area by a few mm (Fig. 2). Small longitudinal incisions are made with a scalpel about 2-3 mm from the free edge and parallel to it. By pulling reasonably strongly with forceps, the free edge unfolds and stretches. Given the force that has to be applied, the surgeon should hold 2 forceps at this stage, one to steady the leaflet and one to unfold it. Repetition of this manoeuvre along the free edge usually, and often surprisingly, succeeds in enlarging it by 2-3 mm. The success of this manoeuvre often differs between different cusps, being most successful in the non-coronary cusp, less so in the right cusp and least successful in the left cusp. This technique, which is useful in the young rheumatic patient, cannot be performed in the older patient because the original free edge rolling has developed into a fibrous band along the free edge while the remaining cusp tissue is still fairly
Surgical Techniques All patients undergo standard cardiopulmonary bypass with distal root and dual caval cannulation. Body temperature is maintained at 34-35°C. A single antegrade high-potassium cold-blood cardioplegia is administered through the coronary ostia followed by retrograde continuous through-coronary sinus cannulation. This is interrupted occasionally for a maximum of 5 to 10 minutes when the return obscures visibility. A swab with ice slush covers the anterior surface of the right ventricle where a thermistor is placed. A left ventricular vent is placed through the superior pulmonary vein. A transverse aortotomy is always performed close to the aortic clamp and away from the commissures. This is curved down the centre of the non-coronary sinus and stopped a few mm from the ammlus. An aortic retractor is used as well as two sutures passed through the lower aortic flap and clipped to the towels in order to facilitate
65
Asia Pacific J Thorac Cardiovasc Surg 1994;3(2)
Lhran Aortic
valve repair
Fig 3. Shaving the free edge of the aortic cusp on the inflow or ventricular aspect.
Fig. 4. Aortic valve commissural annuloplasty.
thin and mobile. Shaving of the inflow aspect of this fibrous bar along each free edge increases cusp mobility (Fig. 3).
haemodynamics. We have reported an experimental study showing that this technique results in an earlier closure of the aortic valve, probably due to an increase in the vortices within the sinuses of Valsalva lg. This is done by placing 2-3 pledgeted “U” stitches on each sinus ridge or sinotubular junction so as to increase its protrusion into the aortic lumen. This vortex increase could reduce the tendency to inward rolling of the leaflet free edges. This is a fast and easy-to-perform manoeuvre that, at worst, is innocuous.
3) annuloplasty by means of placement of a pledgeted “U” stitch at the base of each commissure, which, by plicating the aortic wall, reduces its total circumference. This is done by the placement of a “U” suture with Teflon pledgets, which approximates the two adjacent portions of the aortic wall within each sinus of Valsalva under the commissure (Fig. 4). A double-armed 4/O polypropylene suture is used. This is entered about 3-4 mm from the top of the commissure and 2-3 mm from the leaflet base, through the aortic wall of the sinus, outside the aortic wall, and in again through the aortic wall of the next sinus at the equivalent distance from the leaflet. The other arm is passed a few mm down the sinus, again 2-3 mm from the leaflet base. Once tied, a plicature of the commissural area results which does not interfere with cusp movements. This manoeuvre is repeated at each commissure. This technique, which we described as original, had in fact been applied by Cabrol in 1966 9 and previously by Mulder in 1960 l5 who termed it “tacking a tuck” at the commissures. The degree of cusp retraction determines the amount of annulus constriction needed. As with mitral annuloplasty, over-correction results in stenosis.
If cusp retraction is severe, these repair manoeuvres cannot be used, and extension of all 3 cusps is performed with a single strip of fashioned glutaraldehyde-treated pericardium. We originally used glutaraldehyde-treated commercially available bovine pericardium following the technique described by Batista *O. Although the results were satisfactory, the occurrence of immediate and transient ischaemic changes in several patients led us to study this technique in the laboratory. It was found that cusps which were too high and redundant and which could occlude the coronary ostia resulted. A new technique was developed based on the use of a single strip of autologous pericardium treated for 10 min in 0.5 M buffered glutaraldehyde, shaped into the form of the normal aortic cusps, and of the appropriate size according to the aortic annulus diameter of the individual patient as measured intraoperatively with transoesophageal echocardiography *I. The trimmed pericardial strip is sutured to the leaflet remnant with running 4/O polypropylene sutures started at the midpoint of each leaflet and stopped against each other at the commissures. The new commissure is sutured to the aortic wall with all the knots tied outside the aorta over pledgets (Fig. 6).
4) In cases with prolapse, resuspension of the cusp free edge is also performed, using the technique described by Garamella I6 and popularised by Trusler I7 (Fig. 5). An alternative is triangular resection of the central portion of the prolapsing cusp and re-suture with interrupted 6/O interrupted sutures to restore the appropriate length of the free edge is. 5) In some cases, an enhancement of the supra-aortic ridge is induced in order to improve the valve
66
Asia Pacific
J Thorac
Cardiovasc
Surg 1994;3(2) Aortic
DlUaIl valve repair
Fig. 5. Cusp free edge resuspension.
Fig. 6. Aortic valve cusp extension.
Results
With a maximum follow-up of 6 years (mean 28.7 months), there were 3 late deaths (actuarial survival of 92.62 + 4.33%). Six patients required reoperation, without mortality. Failure of the mitral repair occurred in 2 patients, with one case of resuspension of the bovine pericardium and one case of autologous pericardium excision. The remaining reoperations were due to 2 cases of infective endocarditis (autologous), calcification of one bovine cusp at 50 months, and one commissural tear (autologous) at 8 months.
Since July 1988, repair has been carried out in 280 of the 650 patients (43%) undergoing aortic valve surgery. Plasty techniques were used in 202 patients with a mean age of 21.5 years. Concomitant mitral valve surgery was undertaken in 103 patients (51%). Eight patients (4%) died in hospital, and the late mortality was 4.1% with an actuarial survival of 86.1 f 3.9%, a mean of 20.2 months after operation. No thromboembolic events were detected in patients only undergoing aortic valve surgery. There were 32 reoperations (with no deaths), 22 being due to progressive rheumatic disruption of the mitral repair. There was severe aortic dysfunction in 17 cases (8.7%).
The autologous pericardium excised 8 months after surgery showed a devitalised collagen structure without calcification and a partial layer of re-epithelisation. The mean preoperative degree of aortic regurgitation was 2.98 (graded 0 to 4+). The mean intraoperative residual regurgitation was 0.75. At last follow-up this was 1.1. These results show that this technique is standardised and reproducible with excellent results in terms of valve competence.
This high incidence of reoperations of mitral valve repair in the young patient, which constitutes a serious problem in the Third World, has been reported by us 22. Analysis of the cases of reoperation revealed that those patients with preoperative severe aortic regurgitation (greater than 3+) had a higher likelihood of failure of the repair than those with moderate insufficiency 23. This fimding highlights the limits of this surgery.
The long-term durability of the autologous pericardium is open to question. The importance of mechanical stress in the durability of pericardium has been shown by the significant difference in the behaviour of the Ionescu-Shiley 24 prosthesis compared to the second-generation Carpentier-Edwards pericardial bioprosthesis 25. These findings are supported by the reports of Angel1 26,27 who showed that freehand homograft failure was 12 years versus 8 years when the homograft was mounted on a stent. The absence of a stent and, whenever possible, the presence of a cusp remnant should significantly reduce stress on the pericardium. This lack of stent also reduces transvalvular gradients, which is particularly important in the patient with a small aortic root. Even in the event of failure, the excision of the calcified pericardium should be easy, given that the patient’s leaflet remnants have been preserved.
Because of its previous negative history, extension or replacement of the 3 aortic valve cusps needs to answer 2 main demands. The first is the need for a standard surgical technique that ensures a correct, reproducible and safe result in terms of immediate competence. The second is the long-term durability of the selected material. We recently reviewed our total experience of 78 patients (mean age 27.8 years) who had a cusp extension (bovine pericardium in 27 and autologous pericardium in 51). Twenty-nine patients had simultaneous mitral valve surgery, with 28 undergoing valve repair. There was no hospital mortality or thromboembolic events even though no patient received anticoagulant therapy.
67
Asia Pacific
J Thorac
Cardiovasc
Surg 1994;3(2) Aortic
Indications
7.
As with the mitral valve, the possibility of repair depends primarily on the lesions encountered. Calcified valves are beyond repair. Different attempts at decalcification have yielded short-term results. However, isolated calcific nodules, particularly those often found at the level of one fused commissure, can be shaved off. Thick and rigid valves are beyond present reconstruction techniques. Those valves with moderate regurgitation due to either fibrosis of the otherwise mobile leaflets or annular dilatation are the ideal candidates for repair. This is particularly so when the reason for operation is either severe mitral or coronary disease and where the surgeon feels reluctant to ignore or replace the aortic valve. If the degree of cusp retraction is too great, cusp extension is indicated. Total valve reconstruction with glutaraldehyde-treated autologous pericardium can theoretically be applied to the majority of patients. However, because the long-term durability of this technique is still unknown, we reserve it for young patients where anticoagulation is a problem, and for old patients with small aortic roots. This present work is a tribute to our courageous and imaginative predecessors. Their highly useful techniques were applied at a time when cardiopulmonary bypass and myocardial protection were less developed.
8. 9.
10. 11. 12.
13. 14.
15.
16.
17. 18. 19.
Acknowledgments
20.
Figures l-5 from Duran CMJ, J Cardiac Surg 1993;8:44352, with permission. Fig. 6 from Duran CMJ, J Cardiac Surg 1995 (in press, with permission).
21.
References
22.
1. 2.
3. 4.
5.
6.
Tuffter T. Etat actuel de la cbirurgie intrathoracique. XVII Intemat Congress Medicine, London, Set VII(PtII);l913,247-9. Cutler EC, Levine SA. Cardiotomy and valvulotomy for mitral stenosis. Experimental observations and clinical notes concerning an operative case with recovery. Boston Med Surg 1923;188:1023. Starzl TE, Cruzat EP, Walker FB, et al. A technique for bicuspidisation of the aortic valve. J Thorac Cardiovasc Surg 1959;38:262-70. Hurwitt ES, Hoffert PW, Rosenblatt A. Plication of the aortic ring in the correction of aortic insufficiency. J Thorac Cardiovasc Surg 1960;39:654-62. Taylor WJ, Thrower WB, Black H, et al. The surgical correction of aortic insufficiency by circumclusion. J Thorac Cardiovasc Surg 1958;35:192-205. Murphy JP. The surgical correction of syphilitic aortic insufficiency. J ‘Ihorac Cardiovasc Sttrg 1960;40:524-8.
Referees for 1994 The Editorial Board of the Journal expresses its thanks to all referees for their assistance with reviewing papers submitted for publication throughout 1994. Their efforts are appreciated by the Editorial Board and by authors.
J. Angus D. Baird B. Barratt-Boyes M. Berndt T. Cartmill P. Clarke T. David A. Forbes A. Gale
23. 24.
25.
26. 27.
Bailey CP, Bolton HE, Jamison WL, et al. Commissurotomy for rheumatic aortic stenosis. I. Surgery. Circulation 1954;9:22-31. Brock RC. Surgical treatment of aortic stenosis. Br Med J 1957;1:1019-28. Cabrol C, Cabrol A, Guiraudon G, et al. Le traitement de l’insiffisance aortique par l’annuloplastie aortique. Arch Mal Coeur 1966;59:1305-12. Ross DN. Surgical reconstruction of the aortic valve. Lancet 1963;ii:5714. Bjork VO, Hultquist G. Teflon and pericardial aortic valve prostheses. J ‘Ihorac Cardiovasc Surg 1964;47:693-701. Duran CMG, Alonso J, Gaite L, et al. Long-term results of conservative repair of the rheumatic aortic valve insufficiency. Eur J Cardio ‘l-horac Surg 1988;2:217-23. Duran CMG. Present status of reconstructive surgery for aortic valve disease. J Cardiac Surg 1993;8:443-52. Ghandour M, Al-Halees Z, Duran CMG. A simple me&d for intraoperative visualization of the repaired aortic valve. J Thorac Cardiovasc Surg 1994;107:632-3. Mulder DG, Kattus AA, Longmire WP. The treatment of acquired aortic stenosis by valvuloplasty. J Thorac Cardiovasc Surg 1960; 4k731-43. Garamella JJ, Cmz AB Jr, Heupel WI-I, et al. Ventriculatseptal defect with aortic insufficiency: successful surgical correction of both defects by the transaortic approach. Am J Cardioll960;5:266-72. Trusler GA, Moes CA, Kidd BS. Repair of ventricular septal defect with aortic insufftciency. J Thorac Cardiovasc Surg 1973;66:394-403. Cosgrove DM, Rosnkrantz ER, He&en WG, et al. Valvuloplasty for aortic insufticiency. J Thorac Cardiovasc Surg 1991;102:571-7. Duran CMG, Balasundaram S, Bianchi S, et al. Hemodynamic effect of supra-aortic ridge enhancement on the closure mechanism of the aortic valve and its implication in aortic valve repair. Thorac Cardiovasc Surgeon 1990;38:610. Batista RJW, Dobrianskij A, Commazzi M, et al. Clinical experience with stentless pericardial aortic monopatch for aortic valve replacement. J Thorac Cardiovasc Surg 1987;93: 19-26. Duran CMG, Gallo R, Kumar N. Aortic valve replacement with autologous pericardium: surgical technique. J Cardiac Surgery (in press). Duran CMG, Gometza B, De Vol EB. Valve repair in rheumatic mitral disease. Circulation 1991;84(Suppl III):l25-32. Duran CMG, Gometza B. Aortic valve reconstruction in the young. J Cardiac Surg 1994,9(Suppl):204-8. Nistal S, Garcia-Satue E, Artinano E, Duran CMG, et al. Comparative study of primary tissue valve failure between Ionescu-Shiley pericardial and Hancock porcine valves in the aortic position. Am J Cardiol 1986;57:161-4. Frater RWM, Salomon NW, Rainer G, et al. The Carpentier-Edwards pericardial aortic valve: intermediate results. Ann Thorac Surg 1992;53:764-71. Angel1 WW, Oury JH, Lamberti JJ, el al. Durability of the viable aortic allograft. J Thorac Cardiovasc Surg 1989;98:48-55. Angell WW, Chuy JH, Duran CG, Infantes-Alarcon C. Twenty-year comparison of the human allograft and porcine xenograft. Ann Thorac Surg 1989;48:89-90.
T. Gardner P. Gibson He Guo-Wei A. Hodge C. Hughes T. Karl A. Keogh A. Kerr D. McGiffin
68
Dttratl valve repair
R. Mee C. Munsch M. Newman M. Rabinov D. Ross M. Shanahan G. Shardey P. Skillington J. Smith
G. Stirling D. Thomson A. Tonkin D. Topliss S. Victor C. Ward Z. Wazir D. Wheeldon J. Wisheart
T he positive results achieved with
mitral valve repair encouraged us to rediscover and apply old and often forgotten techniques of aortic valve reconstruction. The benefits and limitation of these techniques have been established over a period of 20 years. Three different techniques of aortic valve reconstruction are used, according to the amount and quality of cusp tissue. One, in patients with enough tissue, “repair” techniques such as commissurotomy, free edge unrolling or shaving, resuspension or annuloplasty can be applied. Two, patients with cusp retraction and severe free edge thickening undergo triple cusp extension with pericardium. Three, patients with fibrosed or even calcified leaflets but a good annulus undergo valve reconstruction with glutaraldehyde-treated autologous pericardium. Since August 1988, 280 patients have undergone aortic valve reconstruction. Repairs were carried out in 202 patients. Hospital mortality was 4% and late mortality was 4.1%. Bovine pericardium was used in 27 patients and reconstruction with autologous pericardium was carried out in 51 patients. There was no hospital mortality in the last two groups; late mortality was 3.8% and the incidence of reoperation was 5.1%. Patients undergoing isolated aortic surgery had no thromboembolic events. These techniques are limited by the amount of cusp tissue for repair and by the still unknown durability of the pericardium for reconstruction. (Asia Pacific J Thorac Cardiovasc Surg 1994;3(2):64-68) Introduction
that aortic reconstruction selected patients.
Reconstructive surgery of the aortic valve has received less attention than the repair of the atrioventricular valves. This is probably due to the better results achieved with aortic valve replacement and the precise geometry needed to achieve competence. The history of aortic valve repair, however, is as long as that of mitral valve repair.
can be safely undertaken in
Surgical Principles Aortic valve reconstruction is not an alternative to replacement. It should rather be considered as part of the surgical armamentarium. As with mitral valve repair, detailed analysis of the valve lesions, both echocardiographically and directly, is essential.
The first aortic commissurotomy was performed by Tuffier 1 in 1913, well before a similar operation on the mitral valve was successfully carried out *. Before the advent of cardiopulmonary bypass, aortic regurgitation was treated with bicuspidisation 3*4 and circumclusion 5*6. Once open heart surgery became an option, a number of reconstructive techniques were explored, including open commissurotomy 7,8, annuloplasty g and cusp extension lo,“.
The surgeon must change his or her attitude so that every aortic valve is always observed carefully even if, as in most cases, it is going to be replaced. Repeated examination should eventually lead the surgeon to consider reconstruction rather than replacement. The actual reconstructive techniques fall into three distinct categories. Those patients judged to have enough valvular tissue undergo a variety of manoeuvres directed towards achieving competence without the use of extravalvular tissue. These techniques, grouped under the heading of “repair”, should be taken as a whole since usually each individual technique only achieves partial improvement and requires reinforcement by other repair techniques i3. In the presence of severe cusp retraction or calcification, “cusp extension” with extravalvular tissue is necessary, provided the base is free and mobile. The positive experience obtained with this technique and the detection of residual gradients in those cases with a thick cusp remnant encouraged us to develop a third category of reconstruction, resulting in total valve replacement with freehand autologous pericardium.
These techniques, because of their rather unpredictable and often poor results, were soon displaced by the far more reliable new prostheses. Nowadays, the vast majority of surgeons treat all aortic lesions by replacement, with the exception of congenital stenotic lesions in the very young and regurgitations secondary to septal defects. Faced with patients who had undergone a successful mitral valve repair and frequently suffered from an associated aortic lesion, we were encouraged to reexplore the possibilities of aortic valve repair. After 20 years of experience using this approach 12, we consider
64
Asia Pacific
J Thorac
Cardiovasc
Surg 1994;3(2) Aortic
DUKUl valve repair
Fig. 1. Aortic valve commissurotomy.
Fig. 2. Unrolling the free edge of the aortic valve,
As with mitral valve repair, a method to evaluate the results of the reconstruction intraoperatively is needed. Direct visual observation of the reconstructed aortic valve through the open aortotomy is totally unreliable. We have used 2 different methods. The first is the direct observation of the aortic valve through the 30-degree optics of a cystoscope introduced through the closed aortotomy while the root is pressurised with clear fluid and the aorta is still cross clamped 14.The second method involves measurement of the return through the left ventricular vent in relation to the pump output. Return percentages below 8-10% have been shown to correspond to non-significant residual regurgitation. Although experience and the regular use of transoesophageal two-dimensional colour Doppler echocardiography have rendered these 2 methods somewhat obsolete, they still have considerable selfteaching value.
exposure. Closure of this aortotomy after repair is easy because of the absence of a rigid prosthesis. Closure is carried out with 2 over-and-over 4/O polypropylene sutures started at each end of the incision and tied to each other at the most anterior part of the aortotomy. Root suction is applied before unclamping the aorta and maintained for several minutes after weaning from bypass. Repair Techniques These “repair” techniques must be applied according to the surgical fmdings and are limited by the amount and quality of valve tissue available. The following manoeuvres are used, most often in combination: 1) commissurotomy, always performed in the presence of even minimal fusion in order to maximise cusp mobility. Often the commissurotomy has to be performed across thickened and even calcified tissue. Shaving of the excess tissue from both cusps, at this level if possible, renders them mobile (Fig. 1). 2) free edge unrolling of each leaflet which increases the cuspal area by a few mm (Fig. 2). Small longitudinal incisions are made with a scalpel about 2-3 mm from the free edge and parallel to it. By pulling reasonably strongly with forceps, the free edge unfolds and stretches. Given the force that has to be applied, the surgeon should hold 2 forceps at this stage, one to steady the leaflet and one to unfold it. Repetition of this manoeuvre along the free edge usually, and often surprisingly, succeeds in enlarging it by 2-3 mm. The success of this manoeuvre often differs between different cusps, being most successful in the non-coronary cusp, less so in the right cusp and least successful in the left cusp. This technique, which is useful in the young rheumatic patient, cannot be performed in the older patient because the original free edge rolling has developed into a fibrous band along the free edge while the remaining cusp tissue is still fairly
Surgical Techniques All patients undergo standard cardiopulmonary bypass with distal root and dual caval cannulation. Body temperature is maintained at 34-35°C. A single antegrade high-potassium cold-blood cardioplegia is administered through the coronary ostia followed by retrograde continuous through-coronary sinus cannulation. This is interrupted occasionally for a maximum of 5 to 10 minutes when the return obscures visibility. A swab with ice slush covers the anterior surface of the right ventricle where a thermistor is placed. A left ventricular vent is placed through the superior pulmonary vein. A transverse aortotomy is always performed close to the aortic clamp and away from the commissures. This is curved down the centre of the non-coronary sinus and stopped a few mm from the ammlus. An aortic retractor is used as well as two sutures passed through the lower aortic flap and clipped to the towels in order to facilitate
65
Asia Pacific J Thorac Cardiovasc Surg 1994;3(2)
Lhran Aortic
valve repair
Fig 3. Shaving the free edge of the aortic cusp on the inflow or ventricular aspect.
Fig. 4. Aortic valve commissural annuloplasty.
thin and mobile. Shaving of the inflow aspect of this fibrous bar along each free edge increases cusp mobility (Fig. 3).
haemodynamics. We have reported an experimental study showing that this technique results in an earlier closure of the aortic valve, probably due to an increase in the vortices within the sinuses of Valsalva lg. This is done by placing 2-3 pledgeted “U” stitches on each sinus ridge or sinotubular junction so as to increase its protrusion into the aortic lumen. This vortex increase could reduce the tendency to inward rolling of the leaflet free edges. This is a fast and easy-to-perform manoeuvre that, at worst, is innocuous.
3) annuloplasty by means of placement of a pledgeted “U” stitch at the base of each commissure, which, by plicating the aortic wall, reduces its total circumference. This is done by the placement of a “U” suture with Teflon pledgets, which approximates the two adjacent portions of the aortic wall within each sinus of Valsalva under the commissure (Fig. 4). A double-armed 4/O polypropylene suture is used. This is entered about 3-4 mm from the top of the commissure and 2-3 mm from the leaflet base, through the aortic wall of the sinus, outside the aortic wall, and in again through the aortic wall of the next sinus at the equivalent distance from the leaflet. The other arm is passed a few mm down the sinus, again 2-3 mm from the leaflet base. Once tied, a plicature of the commissural area results which does not interfere with cusp movements. This manoeuvre is repeated at each commissure. This technique, which we described as original, had in fact been applied by Cabrol in 1966 9 and previously by Mulder in 1960 l5 who termed it “tacking a tuck” at the commissures. The degree of cusp retraction determines the amount of annulus constriction needed. As with mitral annuloplasty, over-correction results in stenosis.
If cusp retraction is severe, these repair manoeuvres cannot be used, and extension of all 3 cusps is performed with a single strip of fashioned glutaraldehyde-treated pericardium. We originally used glutaraldehyde-treated commercially available bovine pericardium following the technique described by Batista *O. Although the results were satisfactory, the occurrence of immediate and transient ischaemic changes in several patients led us to study this technique in the laboratory. It was found that cusps which were too high and redundant and which could occlude the coronary ostia resulted. A new technique was developed based on the use of a single strip of autologous pericardium treated for 10 min in 0.5 M buffered glutaraldehyde, shaped into the form of the normal aortic cusps, and of the appropriate size according to the aortic annulus diameter of the individual patient as measured intraoperatively with transoesophageal echocardiography *I. The trimmed pericardial strip is sutured to the leaflet remnant with running 4/O polypropylene sutures started at the midpoint of each leaflet and stopped against each other at the commissures. The new commissure is sutured to the aortic wall with all the knots tied outside the aorta over pledgets (Fig. 6).
4) In cases with prolapse, resuspension of the cusp free edge is also performed, using the technique described by Garamella I6 and popularised by Trusler I7 (Fig. 5). An alternative is triangular resection of the central portion of the prolapsing cusp and re-suture with interrupted 6/O interrupted sutures to restore the appropriate length of the free edge is. 5) In some cases, an enhancement of the supra-aortic ridge is induced in order to improve the valve
66
Asia Pacific
J Thorac
Cardiovasc
Surg 1994;3(2) Aortic
DlUaIl valve repair
Fig. 5. Cusp free edge resuspension.
Fig. 6. Aortic valve cusp extension.
Results
With a maximum follow-up of 6 years (mean 28.7 months), there were 3 late deaths (actuarial survival of 92.62 + 4.33%). Six patients required reoperation, without mortality. Failure of the mitral repair occurred in 2 patients, with one case of resuspension of the bovine pericardium and one case of autologous pericardium excision. The remaining reoperations were due to 2 cases of infective endocarditis (autologous), calcification of one bovine cusp at 50 months, and one commissural tear (autologous) at 8 months.
Since July 1988, repair has been carried out in 280 of the 650 patients (43%) undergoing aortic valve surgery. Plasty techniques were used in 202 patients with a mean age of 21.5 years. Concomitant mitral valve surgery was undertaken in 103 patients (51%). Eight patients (4%) died in hospital, and the late mortality was 4.1% with an actuarial survival of 86.1 f 3.9%, a mean of 20.2 months after operation. No thromboembolic events were detected in patients only undergoing aortic valve surgery. There were 32 reoperations (with no deaths), 22 being due to progressive rheumatic disruption of the mitral repair. There was severe aortic dysfunction in 17 cases (8.7%).
The autologous pericardium excised 8 months after surgery showed a devitalised collagen structure without calcification and a partial layer of re-epithelisation. The mean preoperative degree of aortic regurgitation was 2.98 (graded 0 to 4+). The mean intraoperative residual regurgitation was 0.75. At last follow-up this was 1.1. These results show that this technique is standardised and reproducible with excellent results in terms of valve competence.
This high incidence of reoperations of mitral valve repair in the young patient, which constitutes a serious problem in the Third World, has been reported by us 22. Analysis of the cases of reoperation revealed that those patients with preoperative severe aortic regurgitation (greater than 3+) had a higher likelihood of failure of the repair than those with moderate insufficiency 23. This fimding highlights the limits of this surgery.
The long-term durability of the autologous pericardium is open to question. The importance of mechanical stress in the durability of pericardium has been shown by the significant difference in the behaviour of the Ionescu-Shiley 24 prosthesis compared to the second-generation Carpentier-Edwards pericardial bioprosthesis 25. These findings are supported by the reports of Angel1 26,27 who showed that freehand homograft failure was 12 years versus 8 years when the homograft was mounted on a stent. The absence of a stent and, whenever possible, the presence of a cusp remnant should significantly reduce stress on the pericardium. This lack of stent also reduces transvalvular gradients, which is particularly important in the patient with a small aortic root. Even in the event of failure, the excision of the calcified pericardium should be easy, given that the patient’s leaflet remnants have been preserved.
Because of its previous negative history, extension or replacement of the 3 aortic valve cusps needs to answer 2 main demands. The first is the need for a standard surgical technique that ensures a correct, reproducible and safe result in terms of immediate competence. The second is the long-term durability of the selected material. We recently reviewed our total experience of 78 patients (mean age 27.8 years) who had a cusp extension (bovine pericardium in 27 and autologous pericardium in 51). Twenty-nine patients had simultaneous mitral valve surgery, with 28 undergoing valve repair. There was no hospital mortality or thromboembolic events even though no patient received anticoagulant therapy.
67
Asia Pacific
J Thorac
Cardiovasc
Surg 1994;3(2) Aortic
Indications
7.
As with the mitral valve, the possibility of repair depends primarily on the lesions encountered. Calcified valves are beyond repair. Different attempts at decalcification have yielded short-term results. However, isolated calcific nodules, particularly those often found at the level of one fused commissure, can be shaved off. Thick and rigid valves are beyond present reconstruction techniques. Those valves with moderate regurgitation due to either fibrosis of the otherwise mobile leaflets or annular dilatation are the ideal candidates for repair. This is particularly so when the reason for operation is either severe mitral or coronary disease and where the surgeon feels reluctant to ignore or replace the aortic valve. If the degree of cusp retraction is too great, cusp extension is indicated. Total valve reconstruction with glutaraldehyde-treated autologous pericardium can theoretically be applied to the majority of patients. However, because the long-term durability of this technique is still unknown, we reserve it for young patients where anticoagulation is a problem, and for old patients with small aortic roots. This present work is a tribute to our courageous and imaginative predecessors. Their highly useful techniques were applied at a time when cardiopulmonary bypass and myocardial protection were less developed.
8. 9.
10. 11. 12.
13. 14.
15.
16.
17. 18. 19.
Acknowledgments
20.
Figures l-5 from Duran CMJ, J Cardiac Surg 1993;8:44352, with permission. Fig. 6 from Duran CMJ, J Cardiac Surg 1995 (in press, with permission).
21.
References
22.
1. 2.
3. 4.
5.
6.
Tuffter T. Etat actuel de la cbirurgie intrathoracique. XVII Intemat Congress Medicine, London, Set VII(PtII);l913,247-9. Cutler EC, Levine SA. Cardiotomy and valvulotomy for mitral stenosis. Experimental observations and clinical notes concerning an operative case with recovery. Boston Med Surg 1923;188:1023. Starzl TE, Cruzat EP, Walker FB, et al. A technique for bicuspidisation of the aortic valve. J Thorac Cardiovasc Surg 1959;38:262-70. Hurwitt ES, Hoffert PW, Rosenblatt A. Plication of the aortic ring in the correction of aortic insufficiency. J Thorac Cardiovasc Surg 1960;39:654-62. Taylor WJ, Thrower WB, Black H, et al. The surgical correction of aortic insufficiency by circumclusion. J Thorac Cardiovasc Surg 1958;35:192-205. Murphy JP. The surgical correction of syphilitic aortic insufficiency. J ‘Ihorac Cardiovasc Sttrg 1960;40:524-8.
Referees for 1994 The Editorial Board of the Journal expresses its thanks to all referees for their assistance with reviewing papers submitted for publication throughout 1994. Their efforts are appreciated by the Editorial Board and by authors.
J. Angus D. Baird B. Barratt-Boyes M. Berndt T. Cartmill P. Clarke T. David A. Forbes A. Gale
23. 24.
25.
26. 27.
Bailey CP, Bolton HE, Jamison WL, et al. Commissurotomy for rheumatic aortic stenosis. I. Surgery. Circulation 1954;9:22-31. Brock RC. Surgical treatment of aortic stenosis. Br Med J 1957;1:1019-28. Cabrol C, Cabrol A, Guiraudon G, et al. Le traitement de l’insiffisance aortique par l’annuloplastie aortique. Arch Mal Coeur 1966;59:1305-12. Ross DN. Surgical reconstruction of the aortic valve. Lancet 1963;ii:5714. Bjork VO, Hultquist G. Teflon and pericardial aortic valve prostheses. J ‘Ihorac Cardiovasc Surg 1964;47:693-701. Duran CMG, Alonso J, Gaite L, et al. Long-term results of conservative repair of the rheumatic aortic valve insufficiency. Eur J Cardio ‘l-horac Surg 1988;2:217-23. Duran CMG. Present status of reconstructive surgery for aortic valve disease. J Cardiac Surg 1993;8:443-52. Ghandour M, Al-Halees Z, Duran CMG. A simple me&d for intraoperative visualization of the repaired aortic valve. J Thorac Cardiovasc Surg 1994;107:632-3. Mulder DG, Kattus AA, Longmire WP. The treatment of acquired aortic stenosis by valvuloplasty. J Thorac Cardiovasc Surg 1960; 4k731-43. Garamella JJ, Cmz AB Jr, Heupel WI-I, et al. Ventriculatseptal defect with aortic insufficiency: successful surgical correction of both defects by the transaortic approach. Am J Cardioll960;5:266-72. Trusler GA, Moes CA, Kidd BS. Repair of ventricular septal defect with aortic insufftciency. J Thorac Cardiovasc Surg 1973;66:394-403. Cosgrove DM, Rosnkrantz ER, He&en WG, et al. Valvuloplasty for aortic insufticiency. J Thorac Cardiovasc Surg 1991;102:571-7. Duran CMG, Balasundaram S, Bianchi S, et al. Hemodynamic effect of supra-aortic ridge enhancement on the closure mechanism of the aortic valve and its implication in aortic valve repair. Thorac Cardiovasc Surgeon 1990;38:610. Batista RJW, Dobrianskij A, Commazzi M, et al. Clinical experience with stentless pericardial aortic monopatch for aortic valve replacement. J Thorac Cardiovasc Surg 1987;93: 19-26. Duran CMG, Gallo R, Kumar N. Aortic valve replacement with autologous pericardium: surgical technique. J Cardiac Surgery (in press). Duran CMG, Gometza B, De Vol EB. Valve repair in rheumatic mitral disease. Circulation 1991;84(Suppl III):l25-32. Duran CMG, Gometza B. Aortic valve reconstruction in the young. J Cardiac Surg 1994,9(Suppl):204-8. Nistal S, Garcia-Satue E, Artinano E, Duran CMG, et al. Comparative study of primary tissue valve failure between Ionescu-Shiley pericardial and Hancock porcine valves in the aortic position. Am J Cardiol 1986;57:161-4. Frater RWM, Salomon NW, Rainer G, et al. The Carpentier-Edwards pericardial aortic valve: intermediate results. Ann Thorac Surg 1992;53:764-71. Angel1 WW, Oury JH, Lamberti JJ, el al. Durability of the viable aortic allograft. J Thorac Cardiovasc Surg 1989;98:48-55. Angell WW, Chuy JH, Duran CG, Infantes-Alarcon C. Twenty-year comparison of the human allograft and porcine xenograft. Ann Thorac Surg 1989;48:89-90.
T. Gardner P. Gibson He Guo-Wei A. Hodge C. Hughes T. Karl A. Keogh A. Kerr D. McGiffin
68
Dttratl valve repair
R. Mee C. Munsch M. Newman M. Rabinov D. Ross M. Shanahan G. Shardey P. Skillington J. Smith
G. Stirling D. Thomson A. Tonkin D. Topliss S. Victor C. Ward Z. Wazir D. Wheeldon J. Wisheart