Ann Thorac Surg 2012;93:e53-e55. doi:10.1016/j.athoracsur.2011.10.045
© 2012 The Society of Thoracic Surgeons
Case Reports
Replacement of a Stented Biologic Prosthesis Within an Aortic Valved Conduit
Giuseppe Gatti, MD*,
Alessandro Moncada, MD,
Alessandro Minati, MD,
Aniello Pappalardo, MD
Division of Cardiac Surgery, Cardiovascular Department, Azienda Ospedaliero–Universitaria Ospedali Riuniti, Trieste, Italy
Accepted for publication October 14, 2011.
* Address correspondence to Dr Gatti, Division of Cardiac Surgery, Cardiovascular Department, AOU Ospedali Riuniti, via Valdoni, 34148 Trieste, Italy (Email: gius.gatti{at}gmail.com).
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Abstract
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A 68-year-old man was referred for severe aortic regurgitation 10 years after aortic root replacement with a valved conduit containing a stented bioprosthesis that had been sutured inside of the vascular tube graft, rather than at its extremity. Because of this simple modification of the Bentall concept, replacing the prosthetic valve within the aortic conduit was easy and uneventful.
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Introduction
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The increasing use of aortic valved conduits incorporating a biologic prosthesis has increased the number of patients who may require reoperation on the aortic root. Although the primary operation yields excellent results with a low risk for morbidity and mortality, reoperation on the aortic root is still challenging [1–4]. In 2008, we described a simple modification of the Bentall concept that was also developed to facilitate repeat surgery in the case of valve failure [5].
A 68-year-old man was referred for severe aortic regurgitation 10 years after aortic root replacement for annuloaortic ectasia with a stented bioprosthetic valved conduit at our unit. Because he was unwilling to take anticoagulants for the rest of his life, in 2001 he underwent an aortic root reconstruction with a 32-mm Hemashield vascular graft (Boston Scientific Corporation, Natick, MA) containing a 27-mm Carpentier-Edwards Perimount valve (Edwards Lifesciences, Irvine, CA). The biologic valve was sutured within the vascular graft rather than at its extremity (Fig 1) [5]. At the time of his operation described here, at 10 years after the primary operation, the patient had begun having dyspnea (New York Heart Association functional class II). Cardiologic assessment revealed severe aortic regurgitation and mild aortic stenosis (mean transprosthetic pressure gradient, 22 mm Hg) owing to structural dysfunction of the prosthetic valve. There was also left ventricular dysfunction of moderate grade (left ventricular ejection fraction, 0.38). Chronic renal failure was a comorbidity factor. The patient's expected operative risk, calculated according to the European System for Cardiac Operative Risk Evaluation, was at 9.7%.
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Fig 1. (A) Step in preparing the composite valved conduit that was used in the primary operation (the original technique) in the case described in the report. A vascular graft 5 mm larger than the labeled valve size is selected and everted at one extremity for approximately 3 cm. The stented bioprosthesis is then placed inside the tube graft and secured to the doubled end of the tube with a continuous polypropylene suture. The everted segment is then pulled down below the valve and beveled as a miniskirt. (B) The polypropylene suture cannot be seen by looking at the upper side of the valve.
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Mediastinal re-entry was easily gained by repeating a median sternotomy, because a computed tomographic (CT) scan had shown no dangerous relationship between the right ventricle and the posterior aspect of the sternum. The remaining segment of the distal ascending aorta was cannulated and repeat aortic root surgery was done with cardiopulmonary bypass and mild systemic hypothermia. After aortic cross-clamping, myocardial protection was achieved with cold crystalloid cardioplegia delivered in both an antegrade and retrograde mode. A 4-cm oblique incision in the aortic graft was begun distally to the anterior strut of the biologic valve. Epiaortic ultrasonographic scanning was very useful in safely performing aortic cannulation, aortic cross-clamping, and incision of the aortic graft. Inspection of the valve confirmed its structural dysfunction, consisting of calcific cuspal stiffening and tearing of the right coronary cusp at the commissure with the noncoronary cusp. After an attempt to remove the valve by simply interrupting the continuous 3-0 polypropylene suture that held it in place, it was excised completely by cutting into the cloth covering the valvular stent, removing the stent, and removing the sewing ring. The subcoronary implantation of a new biologic valve into the conduit was easily achieved by fixing to it the sewing ring of a 27-mm Carpentier-Edwards Magna valve (Edwards Lifesciences) with multiple interrupted mattress sutures of 2-0 braided polyester inserted exactly along the suture line (which was prominent into the graft) of the excised bioprosthesis (Fig 2). The graft incision was then closed with a continuous 3-0 polypropylene suture.
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Fig 2. (A) Subcoronary implantation of the new biologic valve into the graft. The sewing ring of the valve was fixed with multiple interrupted mattress sutures to the graft, exactly along the prominent suture line (arrow) of the excised bioprosthesis (prosthetic vascular fold). (B) The new biologic valve within the graft.
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The patient's postoperative course was uneventful and he was discharged on postoperative day 11.
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Comment
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The past several years have seen a growing interest in aortic valve replacement with biologic prostheses. This has been fueled by the increased durability of biologic valve substitutes, aging of the surgical population, and an appreciation that a two-stage, anticoagulation-avoiding strategy can be a competitive option for valve replacement in young adults as well as older patients. The last point implies that the staged procedure can be technically simple and low-risk, although this is unlikely to be the case when the entire aortic root has been replaced in the first operation [1–4].
In 2008 we described a simple modification of the Bentall concept that was developed to facilitate suturing of the valved conduit to the aortic annulus, to prevent its banding before reaching the distal aorta, and to permit valve upsizing with almost no limitations. At that time we speculated that in case of valve failure, transecting the tube would allow easy access to the valve, and that simply interrupting the single monofilament suture would facilitate removal of the valve without interrupting the proximal suture line between the native aortic annulus and the miniskirt of the graft (Fig 1). Subcoronary implantation of a new prosthetic valve into the conduit might then be even easier than replacing a prosthesis extending into the native valve root [5]. In practice, implantation of the new stented biologic valve into the conduit has proven to be very safe, quick, and easy, mainly because the suture line between the excised bioprosthesis and the vascular graft maintained its prominence into the graft. In addition, this unexpected, permanent fold of the vascular prosthesis allowed us to fix the new valve without resorting to pledgets. Attempted removal of the bioprosthesis by interrupting the single polypropylene suture has proved to be dangerous because of the high risk of injuring the vascular graft. In fact, the polypropylene suture could not be seen by looking at the upper side of the valve (Fig 1). Figure 3
shows a simple improvement of the original technique that solves this problem by simplifying the valve excision.
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Fig 3. (A) The improved technique. (B) The polypropylene suture can be seen by looking at the upper side of the valve.
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Out of 88 consecutive patients who uinderwent aortic root replacement with the stented bioprosthetic valved conduit at our unit from May 2001 throughout June 2011, the case reported here was the sole case of valve failure. Although the patient had an important risk factor for structural dysfunction of a biologic valve (chronic renal failure), dysfunction of his aortic bioprosthesis occurred at a rather early point. This arouses concerns about durability of a biologic valve inside a straight cylindrical graft [6, 7].
This case should demonstrate that replacing a stented biologic prosthesis within an aortic valved conduit is a surgical option.
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References
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Abstract
Introduction
