Ann Thorac Surg 2001;71:1053-1055
© 2001 The Society of Thoracic Surgeons
How to do it
Aortic root remodeling with the "cuff" technique for stentless valve implantation
Massimo Massetti, MDa,
Piergiorgio Bruno, MDa,
Gerard Babatasi, MDa,
Olivier Le Page, MDa,
Eugenio Neri, MDa,
Sebastien Veron, MDa,
Eric Saloux, MDa,
Andre Khayat, MDa
a Department of Thoracic and Cardiovascular Surgery, University Hospital, Caen, France
Accepted for publication August 17, 2000.
Address reprint requests to Dr Massetti, Department of Thoracic and Cardiovascular Surgery, C.H.U. "Cote de Nacre," 14033 Caen, France
e-mail: massetti-m{at}chu-caen.fr
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Abstract
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Aortic root and sinotubular junction dilatation and aneurysm of ascending aorta are considered relative contraindications to implantation of a stentless valve prosthesis, because the modified aortic geometry leads to aortic incompetence and early failure of the prosthesis. Aortic root reconstruction can be performed according to various techniques. We present a surgical technique in which a tubular graft, replacing an ascending aortic aneurysm, allows sinotubular remodeling and satisfactory implantation of a stentless prosthesis. The native aorta is inserted into the vascular prosthesis at the level of the sinotubular junction which is wrapped in order to prevent commissure spreading. Sizing of the vascular and valve prosthesis is made according to annular diameter. Since October 1999, 6 patients have been operated using this technique with good results.
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Introduction
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Over the last decade, aortic valve surgery has been enriched by stentless bioprostheses, a tissue substitute in which elimination of the rigid stent allows implantation of a larger bioprosthesis in any given aortic root [1, 2]. The first advantage is that these prostheses have a better hemodynamic performance than stented prostheses, and the limited contact areas to bloodstream of fabric and suture material may be responsible for the apparent lack of thromboembolic complications and infective endocarditis [2–5]. This more physiologically implanted tissue substitute appears to be superior in terms of durability to stented bioprostheses, and many surgeons have lowered the age of implantation for this substitute [5]. The surgical technique for the Toronto Stentless Porcine Valve (SPVTM) requires intraaortic implantation in a subcoronary position, as recommended by David and associates [1]. In these circumstances, dilatation of the sinotubular junction and ascending aorta opens the commissures, preventing closure of the leaflets, and causing aortic incompetence [6–8]. A poorly defined aortic sinus or sinotubular ridge has therefore been considered to be a relative contraindication to the use of these valve bioprosthesis.
When the aortic root begins to dilate as a result of an aneurysm of the ascending aorta, sinotubular remodeling for a stentless valve implantation can be performed in various ways [2, 7, 8]. We present an alternative technique in which a tubular vascular prosthesis was used to replace the ascending aorta. The sinotubular remodeling was obtained by using the vascular prosthesis as a cuff around the aortic wall. The detailed surgical technique is presented and discussed.
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Technique
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In our institution, a less invasive approach is commonly used for all valvular operations. An 8-cm skin incision is made from the second to the fourth interspace according to our previously reported technique [9]. Cardiopulmonary bypass is instituted between the right atrial appendage and the ascending aorta, to the right of the brachiocephalic trunk. After clamping and transverse section of the aorta, 1 cm above the sinotubular junction, myocardial protection is performed by perfusion of crystalloid cardioplegia directly into the coronary ostia. Retraction of the aortic edges improves exposure. The pathological aortic valve is excised and all calcified deposits are meticulously debrided from the aortic annulus and, if necessary, the left ventricular outflow tract. Due to the greater discrepancy between the annulus and sinotubular junction, the size of the valve is determined by measurement of the annulus alone; a Toronto SPVTM stentless valve is selected and prepared. The valve is secured with two layers of sutures; the first between the left ventricular outflow tract at the ventriculo-aortic junction and the inflow of the stentless valve using a suspended continuous technique with 3-0 polypropylene suture. We prefer this suture technique because, in our experience, it allows to a better coaptation between the native annulus and the Dacron (C.R. Bard, Haverhill, MA) support of the stentless valve; only three knots are necessary to secure the suture of the inflow tract, and there is less risk of an inflammatory response to the implant and the possibility for a better healing at this level. This inflow suture is realized, as David and colleagues [2] recommended, in a single horizontal plane corresponding to the level of the lowest portion of the aortic annulus. The second layer of sutures is located between the aortic sinus and the free margin of the stentless valve with continuous 4-0 polypropylene sutures. Suturing the Toronto SPVTM to the aortic root can be technically demanding and extreme care must be taken to avoid damage to the valve leaflets by the suture needle or other surgical instruments. At the end of the implantation, due to dilatation of the sinotubular junction, the three leaflets of the stentless valve appear to be laterally displaced with lack of coaptation and valve incompetence. The commissure spreading mechanism in the presence of sinotubular junction dilatation is clearly illustrated in Figure 1 and explains the subsequent development of aortic incompetence. The ascending aorta is replaced by a prosthetic graft correcting the sinotubular junction to prevent the development of aortic incompetence. As shown in Figure 2, the three commissures are inserted in the proximal extremity of the tubular graft and are marked at equal distances with three sutures. They are placed symmetrically on the proximal side of the tubular prosthesis, approximately 15 mm from the edge of the prosthesis to allow room for a prosthetic cuff prepared for remodeling the sinotubular junction. The native aorta is inserted into the prosthesis, and the three sutures are tied so that the three commissures are precisely adjusted onto the tube. The sizing of the vascular prosthesis is made according to the annulus diameter (the same as the prosthetic valve) taking into account the thickness of the aortic wall. Usually, a 2 to 3 mm larger diameter vascular prosthesis allows the remodeling of the sinotubular junction in order to correct the mechanism of the aortic insufficiency. The proximal extremity of the native aorta, inserted into and reshaped by the prosthesis, is attached by a running suture placed away from the proximal edge of the tube. The distal aorta is trimmed and its diameter is adjusted. The distal anastomosis is performed with a standard technique. Intraoperative transesophageal echocardiography enables accurate deairing of the heart, and allows the exact assessment of leaflet motion and coaptation and the intraoperative evaluation of the left ventricular outflow tract. Continuous wave and color Doppler echocardiography study tests correct functioning of the implant and the absence of any residual regurgitation.
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Fig 1. The spreading mechanism of the commissures in the presence of dilatation of the sinotubular junction.
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Fig 2. The sinotubular junction remodeling technique is obtained using a tubular graft inserted as a "cuff" in the proximal extremity of the ascending aorta. The vascular prosthesis is selected in order to reduce the diameter of the sinotubular junction to that of the native annulus.
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Our experience with this particular technique began in October 1999; since then, 6 patients have been operated without mortality and only with minimal morbidity. By echocardiography, only trivial incompetence is present in 2 patients. These clinical results, although follow-up is short, justifies expansion of the indications for aortic root reconstruction in patients previously considered not to be candidates.
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Comment
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Although the superior hemodynamics and excellent longevity of stentless prostheses have been widely documented, their widespread application has been limited by the complexity of implantation. The aortic valve is a complex structure including the annulus, valve leaflets, sinuses, sinotubular junction, and aortic wall. These structures work in synergy to maintain valve competence. The sinotubular junction is a critical structure: it belongs functionally to the valve apparatus although anatomically is already part of the aorta. In the native valve during diastole, the sinuses expand; given that the sinuses functionally behave as the "stents" for a nonstented valve, bulging of the sinuses during diastole pulls the valve commissures away from each other leading to valve incompetence.
Aortic incompetence commonly occurs after implantation of a stentless biological valve [6]. Although aortic incompetence is usually mild, it may nevertheless predispose to premature valve failure due to either increased leaflet mechanical stress or infective endocarditis.
The stentless bioprosthesis is secured entirely in the patient’s aortic root, as opposed to stented bioprostheses which are secured solely in the aortic annulus. The diameters of the Toronto SPVTM resemble those of a cylinder with approximately equal external diameters at the inflow and outflow levels. It is therefore important that the diameters of the patient’s aortic annulus and sinotubular junction are the same. When the diameter of the sinotubular junction is more than 2 mm larger than that of the aortic annulus, the choice of the diameter of bioprosthesis must be equal to, or slightly larger than, the diameter of the aortic annulus, and the diameter of the sinotubular junction is reduced surgically to the diameter of the SPVTM.
Reconstruction of aortic root geometry has been proposed to overcome these problems. Various techniques have been put forth. David and colleagues [2] suggested aortic root remodeling either by plicating the ascending aorta or by suturing a strip of Dacron fabric outside the aorta at this level. The plication sutures are placed in the sinotubular ridge onto the commissural post, in order to decrease the circumference of the sinotubular ridge. The length of this strip should be 4 to 5 mm longer than the product of the diameter of the Toronto SPVTM x 
; it is secured to the arterial wall at the level of the sinotubular junction and divided into approximately three equal parts to correspond to each commissure of the SPVTM.
Other authors [7, 8] have proposed plication sutures that can be placed in the dilated sinuses to create pleats. From one to four plication sutures may be required, and plication of the right as well as the noncoronary sinus may be necessary. It is critical for the new sinotubular ridge to be equal to, or slightly less than, the diameter of the Toronto SPVTM in-flow to prevent splaying of the commissural post with resultant loss of central coaptation and valve incompetence. The aorta is closed using a strip of Teflon (Impra Inc, subsidiary of L.R. Bard, Tempe, AZ), acting as a buttress to prevent further dilatation. If sinotubular tailoring is required and the distal aorta is larger than the new proximal aorta, a small wedge of aorta can be removed to allow matching of the new sinotubular circumference to the distal aortic circumference.
When an ascending aortic aneurysm is present, the sinotubular junction tends to progressively enlarge and, in these circumstances, a stentless prosthesis is contraindicated. Replacement of the ascending aorta with a tubular graft does not remodel the sinotubular junction because of its lower position in the aortic root. The proposed technique overcomes this problem; the tubular vascular prosthesis both replaces the aortic aneurysm and remodels the sinotubular junction allowing implantation of a stentless aortic bioprosthesis. The proximal end of the native aorta, inserted into and reshaped by the prosthesis, is sutured 15 mm away from the proximal edge of the tube. This sort of "miniskirt" acts as a cuff to reshape the sinotubular junction to a diameter equal to that of annulus to ensure a competent and correctly functioning stentless implant.
It is important to understand the interrelations between the stentless valve and aortic root remodeling to improve both the surgical technique and the long-term outcome. Despite the slightly increased difficulty of this surgery, the surgical approach to the aortic root and stentless valve implantation must be individually tailored to each patient’s anatomy.
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Acknowledgments
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The authors thank Mrs Rossella Mercuri and Mr Bertrand Bachet of St. Jude Medical for their technical assistance in preparing the illustrations. We thank the surgical and nursing staff of the Cardiothoracic Surgery Unit at C.H.U. Caen University Hospital.
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References
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Abstract
Introduction
