Ann Thorac Surg 1997;64:1197-1200
© 1997 The Society of Thoracic Surgeons
How To Do It
Implantation of the Toronto SPV Stentless Porcine Bioprosthesis in Dilated Ascending Aorta
Robert P. Siebenmann, MD
Cardiovascular Surgery, HerzZentrum Hirslanden, Zürich, Switzerland
Accepted for publication May 2, 1997.
 |
Abstract
|
|---|
In the presence of severe dilatation of the ascending aorta the implantation of a Toronto SPV stentless bioprosthesis is compromised by the risk of postoperative central regurgitation. A modification of the implantation technique is described that restores the normal shape of the ascending aorta and thereby avoids the risk of dysfunction of the prosthesis.
|
Introduction
|
|---|
The Toronto SPV valve (St. Jude Medical, St. Paul, MN) is a stentless porcine heterograft for aortic valve replacement, designed for subcoronary freehand implantation. The main advantage is superiority in hemodynamics compared with stented valves, particularly in small aortic roots. Midterm follow-up studies revealed excellent valve performance with gradients similar to homografts and significantly better regression of left ventricular mass index compared with stented valves [1, 2]. However, there are anatomic situations difficult or impossible to implant this type of valve, eg, severely dilated ascending aorta. One of the most important points to avoid postoperative regurgitation is to assess the diameter of the ascending aorta at the level of the sinotubular junction for correct matching of the prosthesis [1, 3]. Moderate dilatation of the ascending aorta distal to the sinotubular junction allows use of the standard implantation technique. In case of severe dilatation of the ascending aorta including the sinotubular junction, another type of valve is indicated, or a surgical repair is mandatory. We have designed a technique of repair that can be used in this situation and used it successfully in 3 patients.
|
Technique
|
|---|
Standard extracorporeal circulation is installed with moderate hypothermia (30°C). A left ventricular vent is introduced through the right upper pulmonary vein. The aorta is cannulated as distally as possible. The ascending aorta is dissected as far as feasible. The aorta is cross-clamped close to the origin of the innominate artery. Cardioplegic arrest is introduced by antegrade cardioplegia and maintained by continuous retrograde cold blood cardioplegia. If the diameter at the level of the sinotubular junction is severely increased, a transverse incision is performed proximally to the sinotubular junction, close to the origin of the right coronary artery (in contrast to the usual level of the incision distal to the sinotubular junction). The transverse incision includes the anterior and lateral parts of the aortic root, leaving the posterior wall intact. An additional longitudinal incision is made anteriorly up to the aortic cross-clamp, resulting in a T-shaped combination of incisions (Fig 1
). The excessive tissue of the aortic wall is reduced by resecting triangular parts at either side, taking into account the grade of dilatation at each level, particularly at the level of the sinotubular junction (Fig 2). Attention is paid to the amount of reduction: for a diameter reduction of 1 cm, a wall resection of 3.1 cm is necessary ([C1 - C2] = 
x [D1 - D2], where C = circumference, D = diameter, and = 3.14). The aortic valve is excised and the annulus decalcified. The size of the prosthesis is determined, exceeding the diameter of the aortic annulus by 2 mm. The amount of diameter reduction at the prospective level of the valve pillars is confirmed by positioning of the valve sizer at the corresponding level and—if necessary—corrected by additional resection. The proximal suture row is then performed by standard technique using interrupted 4-0 single stitch sutures. Necessarily, the three pillars of the prosthesis overlap the rim of the remaining part of the aortic root as a consequence of the proximal level of the transverse incision (Fig 3). Now the subcoronary suture row is performed as far as possible, using 4-0 Prolene (Ethicon Inc, Somerville, NJ) running sutures. These sutures are interrupted at the point where the pillars of the prosthesis cross the level of the transverse incision. Then the transverse part of the aortic incision is closed by 4-0 Prolene running suture; care has to be taken that the two different diameters of the proximal and the distal part are gradually approximated (sliding plasty) (Fig 4). Now the three commissural stay stitches can be placed in the distal part of the redimensioned ascending aorta. The subcoronary suture can now be completed using the access through the remaining longitudinal incision (Fig 5). Finally, the longitudinal incision is closed using a 4-0 Prolene running suture. The heart is deaired and the aorta unclamped. A polyester net (Mersilene, Ethicon Inc) is wrapped around the ascending aorta, secured proximally by the three commissural stitches and distally by several additional stitches (Fig 6).
View larger version (23K):
[in this window]
[in a new window]
|
Fig 1. . T-shaped combination of transverse and longitudinal aortic incisions. The level of the transverse incision is more proximal than in standard technique and approaches the origin of the right coronary artery.
|
|
View larger version (24K):
[in this window]
[in a new window]
|
Fig 2. . Wall reduction of the ascending aorta. After reconstruction, edges marked with B and C meet at point A. A diameter reduction of 1 cm is achieved by wall resection of 3.1 cm (distance B–C).
|
|
View larger version (30K):
[in this window]
[in a new window]
|
Fig 3. . The proximal suture row is completed. The running distal (subcoronary) suture row is interrupted at the point where the pillars overlap the rim of the proximal part of the aortic root.
|
|
View larger version (25K):
[in this window]
[in a new window]
|
Fig 4. . The transverse aortic incision is closed, thereby gradually approximating the two different diameters proximal and distal to the incision (sliding plasty).
|
|
View larger version (27K):
[in this window]
[in a new window]
|
Fig 5. . The distal suture is completed through the remaining longitudinal incision of the ascending aorta.
|
|
|
Results
|
|---|
This implantation technique has been successfully applied in 3 patients. Patient 1 is a 53-year-old woman with severe calcified aortic stenosis, normal left ventricular ejection fraction, and normal coronary arteries. Her ascending aorta was severely dilated to a maximal diameter of 50 mm (reference diameter at the level of the aortic arch, 25 mm). The diameters of the annulus and the sinotubular junction were 27 mm and 35 mm, respectively. The sinuses were not significantly dilated. A no. 29 Toronto SPV valve was implanted, and the ascending aorta was reduced to the appropriate size. The postoperative course was uneventful. Intraoperative and postoperative echocardiographic studies show normal performance of the prosthesis with a mean systolic gradient of 4 mm Hg and no insufficiency. The diameter and the shape of the ascending aorta are normal (35 mm). Follow-up time is 7 months, with freedom from symptoms and unchanged echocardiographic result.
Patient 2 is a 60-year-old woman with severe calcified aortic stenosis, normal left ventricular ejection fraction, and normal coronary arteries. Her ascending aorta was severely dilated to a maximal diameter of 49 mm (Fig 7) (reference diameter at the level of the aortic arch, 24 mm). The diameters of the annulus and the sinotubular junction were 25 mm and 35 mm, respectively. The sinuses were not significantly dilated. A no. 27 Toronto SPV valve was implanted, and the ascending aorta was reduced to the appropriate size. The postoperative course was uneventful. Postoperative echocardiography shows a normal function of the prosthesis with a mean systolic gradient of 7 mm Hg and no insufficiency. The diameter and the shape of the ascending aorta are normal (34 mm) (Fig 8). Follow-up time is 4 months, with freedom from symptoms and unchanged echocardiographic result.
View larger version (173K):
[in this window]
[in a new window]
|
Fig 7. . Preoperative angiogram shows severely dilated ascending aorta including the sinotubular junction (2).
|
|
View larger version (72K):
[in this window]
[in a new window]
|
Fig 8. . Postoperative transesophageal echocardiogram shows normal shape of the ascending aorta and normal position of the prosthesis with good coaptation of the leaflets (patient 2).
|
|
Patient 3 is a 76-year-old man with severe calcified aortic stenosis, moderately impaired left ventricular function, and normal coronary arteries. His ascending aorta was dilated to a maximal diameter of 55 mm (reference diameter at the level of the aortic arch, 28 mm). The diameters of the annulus and the sinotubular junction were 29 mm and 38 mm, respectively. The sinuses were not significantly dilated. A no. 29 Toronto SPV valve was implanted, and the ascending aorta was reduced to the appropriate size. Besides a reoperation for sternal dehiscence, the postoperative course was uneventful. Postoperative echocardiography shows normal function of the prosthesis with a mean gradient of 4 mm Hg and no insufficiency. The diameter and the shape of the ascending aorta are normal (37 mm). Follow-up is 2 months, with freedom from symptoms.
|
Comment
|
|---|
This modified implantation technique has two basic advantages. First, it allows the implantation of a scalloped stentless bioprosthesis in spite of dilatation of the aortic root, eliminating the concern of central insufficiency, which otherwise could be caused by inappropriate distance of the three pillars. Compared with simple folding of the aortic wall in the area of the noncoronary sinus, this technique maintains the anatomic symmetry by gradual reduction of the diameter along the whole length of the transverse incision. Thus the correct placement of the three pillars of the prosthesis is easier, and the hazard of insufficiency due to uneven distances between the three pillars is eliminated. Second, the aneurysmal ascending aorta is reduced to a normal size and reinforced by a polyester net. Thus, the potential for recurrence of dilatation with subsequent aortic regurgitation is reduced. Treatment of ascending aortic aneurysm by remodeling and external reinforcement with a Dacron graft has been proposed by Robicsek and Thubrikar [6] as an alternative to graft replacement. With a similar technique, a polyester net has been used as external wall support by Egloff and associates [5]. Long-term follow-up studies have shown good survival rates and a low rate of recurrence, provided that the ascending aorta has been reinforced after remodeling [5–8]. However, remodeling of the ascending aorta without external support has been shown to have a high rate of recurrence and is therefore not advisable [9].
The flexibility and elasticity of the aorta at the level of the sinotubular junction seems to be essential for the superior hemodynamics of the Toronto SPV valve and is considered to improve the longevity of this type of bioprosthesis [10, 11]. Reinforcement with a thin and flexible polyester net conserves this natural feature of the ascending aorta. In our own experience, an ascending aorta reinforced by a polyster net has remained soft and flexible at reoperation after years.
However, this implantation technique should be limited to patients with the fusiform type of aneurysm. In the presence of severely dilated sinuses, it should be taken into account that part of the diseased tissue would remain unsupported and therefore be prone to the risk of further dilatation with time.
|
Footnotes
|
|---|
Address reprint requests to Dr Siebenmann, HerzZentrum Hirslanden, Witellikerstrasse 36, CH-8008 Zürich, Switzerland.
|
References
|
|---|
- David TE, Feindel CM, Bos J, Sun Z, Scully HE, Rakowski H. Aortic valve replacement with a stentless porcine aortic valve. J Thorac Cardiovasc Surg 1994;106:1030–6.
- Jin XY, Zhang ZM, Gibson DG, Yacoub MH, Pepper JR. Effects of valve substitute on changes in left ventricular function and hypertrophy after aortic valve replacement. Ann Thorac Surg 1996;62:683–90.[Abstract/Free Full Text]
- Kunzelman KS, Grande KJ, David TE, Cochran RP, Verrier ED. Aortic root and valve relationships. J Thorac Cardiovasc Surg 1994;107:162–70.[Abstract/Free Full Text]
- Robicsek F. A new method to treat fusiform aneurysms of the ascending aorta associated with aortic valve disease: an alternative to radical resection. Ann Thorac Surg 1982;34:91–4.
- Egloff L, Rothlin M, Kugelmeier J, Senning A, Turina M. The ascending aortic aneurysm: replacement or repair? Ann Thorac Surg 1982;34:117–24.[Abstract/Free Full Text]
- Robicsek F, Thubrikar MJ. Conservative operation in the management of annular dilatation and ascending aortic aneurysm. Ann Thorac Surg 1994;57:1672–4.[Abstract/Free Full Text]
- Carrel T, von Segesser L, Jenni R, et al. Dealing with dilated ascending aorta during aortic valve replacement: advantages of conservative surgical approach. Eur J Cardiothorac Surg 1991;5:137–43.[Abstract/Free Full Text]
- Barnett MG, Fiore AC, Vaca KJ, Milligan TW, Barner HB. Tailoring aortoplasty for repair of fusiform ascending aortic aneurysm. Ann Thorac Surg 1995;59:497–501.[Abstract/Free Full Text]
- Mueller XM, Tevaearai HT, Genton CY, et al. Drawback of aortoplasty for aneurysm of the ascending aorta associated with aortic valve disease. Ann Thorac Surg 1997;63:762–7.[Abstract/Free Full Text]
- Walther T, Falk V, Autschbach R, et al. Hemodynamic assessment of the stentless Toronto SPV bioprosthesis by echocardiography. J Heart Valve Dis 1994;3:657–65.[Medline]
- Vesely I, Krucinsky S, Campbell B. Micromechanics and mathematical modeling: an inside look at bioprosthetic valve function. J Cardiac Surg 1992;7:85–95.[Medline]
This article has been cited by other articles:
|
|
|
|
 
R. P. Siebenmann, G. Babatasi, and A. Khayat
Dilated aortic root and stentless valve implantation.
Ann. Thorac. Surg.,
February 1, 2002;
73(2):
694 - 695.
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Massetti, G. Babatasi, and A. Khayat
Dilated aortic root and stentless valve implantation: Reply
Ann. Thorac. Surg.,
February 1, 2002;
73(2):
694 - 695.
[Full Text]
[PDF]
|
|
|
|
|
|
|
K. Furukawa, H. Ohteki, Z.-L. Cao, K. Doi, Y. Narita, N. Minato, and T. Itoh
Does dilatation of the sinotubular junction cause aortic regurgitation?
Ann. Thorac. Surg.,
September 1, 1999;
68(3):
949 - 953.
[Abstract]
[Full Text]
[PDF]
|
|
|
Top
Abstract
Introduction
