Asian Cardiovasc Thorac Ann 2008;16:47-49
© 2008 Asia Publishing EXchange Ltd
Replacement of Right Coronary Leaflet With Bovine Pericardium
Liang Tao, MD,
Xiang-Jun Zeng, MD
Department of Cardiac Surgery, Wuhan Asia Heart Hospital, Wuhan, China
For reprint information contact: Xiang-Jun Zeng, MD, Tel: 86 27 6377 6043, Fax: 86 27 8585 4036, Email: zengxiangjun{at}sohu.com, Jinghan Ave #753, Wuhan 430022, Hubei, China.
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ABSTRACT
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Bovine pericardium was used to replace the right coronary leaflet to manage aortic insufficiency resulting from ventricular septal defect in 6 patients aged 15 to 34 years. Aortic insufficiency was severe in 5 patients and moderate in one. In all patients, the ventricular septal defect was repaired before aortic valvuloplasty. They were followed up for 5 to 6 months. No mortality was observed. Three patients had relief of aortic insufficiency, 2 had mild residual aortic insufficiency, and one had minor insufficiency not requiring re-operation. Replacement of the right coronary leaflet with bovine pericardium is a promising technique for young patients. The short-term outcomes are encouraging, but longer follow-up is required to assess the durability and function of bovine pericardium in the aortic position.
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INTRODUCTION
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Aortic insufficiency (AI) is commonly associated with ventricular septal defect (VSD), especially a subpulmonary VSD. The frequency of native aortic valve repair in the young is increasing, reflecting a lack of consensus on the optimal therapeutic solution from the growing number of mechanical and biological prostheses. Furthermore, enthusiasm for the Ross pulmonary autograft operation was dampened in some centers when longer follow-up revealed severe implications such as potential double semilunar valve disease, neoaortic insufficiency, future right ventricular outflow tract homograft re-intervention, and risk of aortic root re-operation.1–3 Recently, Odim and colleagues4 reported the results of a glutaraldehyde-preserved autologous pericardial leaflet extension for repairing the aortic valve. This report reviews our initial experience of replacing the pathological right coronary leaflet with bovine pericardium to repair AI.
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PATIENTS AND METHODS
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From September 2005 to December 2005, aortic valvuloplasty was performed in 6 patients, using bovine pericardium. There were 5 men and 1 woman. Their mean age was 25 ± 9.2 years (range, 15 to 34 years), and mean weight was 53.9 ± 4.8 kg (range, 46 to 57.5 kg). All 6 patients were routinely investigated by transthoracic and transesophageal echocardiography. One patient had moderate AI and 5 had severe AI. All patients had been diagnosed with a subpulmonary VSD. One patient had combined mitral and tricuspid insufficiency, one had associated rupture of the right sinus of Valsalva, and one had a previously repaired VSD. At the time of operation, 5 patients were classified in New York Heart Association (NYHA) functional class II, and one was in NYHA class III. The mean diastolic pressure was 55.3 ± 4.3 mm Hg (range, 50 to 60 mm Hg), mean systolic pressure was 131.3 ± 18.1 mm Hg (range, 106 to 160 mm Hg), and mean pulse pressure was 76 ± 21.5 mm Hg (range, 48 to 110 mm Hg). The mean left ventricular end-diastolic diameter was 71 ± 9 mm (range, 62 to 88 mm). Left ventricular function was normal in 3 patients whose ejection fraction was more than 0.60; the other 3 patients had mildly impaired left ventricular function, with a mean ejection fraction of 0.567 ± 0.039. The indication for operation was moderate or severe AI.
Moderate hypothermia with core cooling to 25°C–28°C, single or bicaval venous cannulation, and a left ventricular vent were used. Myocardial protection consisted of topical hypothermia and hyperkalemic cardioplegic arrest. If significant aortic regurgitation was observed, the cardioplegic solution was infused directly into the coronary ostia after the aortic root had been opened. Repeated doses of cardioplegia were given at intervals throughout the operation if needed. The ascending aorta was incised and retracted, and the valve area was inspected. In deciding on repair, preoperative echocardiographic criteria and intraoperative observations were combined to determine the feasibility and durability of reconstruction. However, the intraoperative observations weighed heavily in the final decision on valve repair. The aortic valve situation determined the type of repair procedure. In all 6 patients, the aortic valve had the characteristic appearance of right coronary leaflet prolapse or bearing retracted cusps, but the noncoronary and left coronary leaflets were normal. The lengths of the free edges of the noncoronary and left coronary leaflets were measured as far as the distance between the nodulus of Arantii and the noncoronary annulus. The pathological right coronary leaflet was resected. The bovine pericardial patch was prepared for the bioprosthetic valve. It was cut as a sector (Figure 1
). The base of the sector equaled half the sum of the length of the noncoronary and left coronary leaflet free edges. The height of the sector was the length from the nodulus of Arantii to the noncoronary annulus. The arc of the sector was running sutured to the right coronary annulus using 5/0 polypropylene. The suture was tied on the outside of the ascending aorta over a Teflon buttress. Prior to closing the incision, aortic root leaflet coaptation was evaluated for adequate area of central leaflet coaptation. The root was closed with a running polypropylene suture over a strip of pericardium. After closure of the aortic root, the pressure generated during the final infusion of warm blood antegrade cardioplegia at the calculated physiologic coronary flow rates provided a reasonable estimate of valve competency before removal of the aortic cross clamp. After separation from cardiopulmonary bypass, intraoperative transesophageal echocardiography was used to validate early competence of the repaired valve. Concomitant procedures included VSD repair in 5 patients, mitral, tricuspid, and pulmonary valve repair in one, and repair of a rupture of the right sinus of Valsalva in one.
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Figure 1. The bovine pericardium is not molded but cut as a sector with the following dimensions: (a) half the length of the noncoronary leaflet free edge, (b) half the length of the left coronary leaflet free edge, (c) the length from the nodulus of Arantii to the noncoronary annulus.
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All 6 patients were followed up by two-dimensional echocardiography with Doppler studies, and aortic regurgitation was assessed. Follow-up echocardiography data were collected within 5 to 6 months postoperatively.
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RESULTS
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There was no mortality or morbidity associated with the operation. Mean cardiopulmonary bypass time was 124.7 ± 30.9 min (range, 93 to 165 min), and mean aortic cross clamp time was 76.3 ± 24.8 min (range, 47 to 106 min). Intraoperative echocardiography demonstrated successful repair with normal coaptation of the leaflet in all patients, and no further modification was required. The patients were discharged from hospital within 12 days and remained symptom-free at follow-up. Transesophageal echocardiography at the time of hospital discharge showed a significant reduction of AI, and the results were statistically meaningful. Mild aortic regurgitation was detected in 2 patients, and no aortic regurgitation was found in the others. The diastolic pressure increased and the pulse pressure decreased significantly after repair. The mean diastolic pressure was 63.3 ± 5.2 mm Hg (range, 60 to 70 mm Hg), and the mean pulse pressure was 43.3 ± 5.2 mm Hg (range, 40 to 50 mm Hg).
Follow-up ranged from 11 to 14 months. Doppler echocardiography at the last follow-up showed 3 patients no longer had AI, 2 had mild residual AI, and one had moderate AI not requiring re-operation.
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DISCUSSION
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Successful aortic valve repair requires an understanding of the anatomy and pathology of the aortic root. The ideal substitute for the aortic valve remains elusive despite progress and improvements in mechanical and bioprosthetic valves, allograft biology, and Ross’s introduction of the pulmonary autograft. The biologic constraints of body growth and calcium metabolism along with prosthesis-patient mismatch and the limitations of synthetic valve substitutes have been manifested by complications such as bleeding and thromboembolic events. Therefore, the long-term durability of such options was put in doubt. Furthermore, the high cost of valvular disease management puts the current surgical options out of reach for the majority.
Aortic valve repair is slowly evolving. The pulmonary autograft is an attractive alternative, but long-term follow-up showed inherent structural wall abnormalities in the pulmonary trunk, predisposing to neoaortic dilation and an increased rate of autograft failure.5 Disappointed by these options, some groups have started to revisit aortic valve repair. Suspending the commissure of the valve and folding the middle of the leaflet are the usual techniques; however, the results have not been encouraging. Pathological changes are localized to the right coronary leaflet but the left and noncoronary leaflets are usually normal in AI associated with VSD. The key action is to correct the pathological changes of the right coronary leaflet.
Calcification of pericardium is predestined. The bovine pericardium used in these patients was that used to manufacture bovine pericardial bioprostheses, which were found to be free of calcification for approximately 10 years. It is expected that when used to make a single aortic valve leaflet, it should also be free of calcification for at least 10 years. The bovine pericardium was not molded during operation and it was flat before it was sewn to the aortic annulus. The quality of the bovine pericardium will determine how long the patients are free from re-operation.
These patients have been followed up for one year; all have either no or mild AI and no aortic stenosis at this point. Certainly, further follow-up is most important. Although our patient group is small and the follow-up is short, this technique provides a promising method of repairing AI, especially that associated with VSD.
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ACKNOWLEDGMENTS
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The authors are thankful to Beijing Balance Bio-Engineering Co. Ltd, who provided the bovine pericardium.
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REFERENCES
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- Laudito A, Brook MM, Suleman S, Bleiweis MS, Thompson LD, Hanley FL, et al. The Ross procedure in children and young adults: a word of caution. J Thorac Cardiovasc Surg 2001;122:147–53.[Abstract/Free Full Text]
- Pessotto R, Wells WJ, Baker CJ, Luna C, Starnes VA. Midterm results of the Ross procedure. Ann Thorac Surg 2001;71(5 Suppl):S336–9.[Medline]
- Al-Halees Z, Pieters F, Qadoura F, Shahid M, Al-Amri M, Al-Fadley F. The Ross procedure is the procedure of choice for congenital aortic valve disease. J Thorac Cardiovasc Surg 2002;123:437–42.[Abstract/Free Full Text]
- Odim J, Laks H, Allada V, Child J, Wilson S, Gjertson D. Results of aortic valve-sparing and restoration with autologous pericardial leaflet extensions in congenital heart disease. Ann Thorac Surg 2005;80:647–54.[Abstract/Free Full Text]
- Niwa K, Perloff JK, Bhuta SM, Laks H, Drinkwater DC, Child JS, et al. Structural abnormalities of great arterial walls in congenital heart disease: light and electron microscopic analyses. Circulation 2001;103:393–400.[Abstract/Free Full Text]
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ABSTRACT
INTRODUCTION
