Ann Thorac Surg 2006;82:316-318
© 2006 The Society of Thoracic Surgeons
Case report
Simple Mechanical Aortic Valve Closure in Ventricular Assist Device Recipients
Mark R. Tasset, MD,
Minoo N. Kavarana, MD,
Laman A. Gray, MD,
Robert D. Dowling, MD
*
Department of Cardiothoracic Surgery, University of Louisville, Louisville, Kentucky
Accepted for publication June 27, 2005.
* Address correspondence to Dr Dowling, 201 Abraham Flexner Way, Louisville, KY 40202 (Email: jwalsh{at}ucsamd.com).
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Abstract
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Patients with mechanical aortic valves that develop refractory heart failure may require left ventricular assist devices. These patients have an increased risk of postoperative thromboembolic events due to intermittent valve opening. Previously described techniques to address this problem can result in a significantly increased ischemic time. We describe a simple but novel technique to close the mechanical aortic prosthesis in an expeditious manner.
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Introduction
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The use of left ventricular assist devices (LVADs) in patients with mechanical aortic valves has resulted in thromboembolic events due to intermittent valve opening. Therefore patients with mechanical prostheses require replacement of the valve with a tissue valve [1] or closure with a pericardial or Gore-Tex patch (W.L. Gore & Assoc, Flagstaff, AZ) [2]. Retrospective reviews suggest that patch closure of mechanical aortic valves does not increase the immediate perioperative risks of LVAD insertion [3].
In this report we present an alternative method for closure of mechanical aortic valves that were successfully utilized in 2 patients. Our single stitch technique is simple, effective, and obviates the need for patch exclusion of mechanical aortic valves or replacement with tissue valves.
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Case Reports
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Patient 1
A 59-year-old man with a history of coronary artery bypass and aortic valve replacement with a Medtronic-Hall mechanical valve (Medtronic, Inc, Minneapolis, MN) presented with symptoms of congestive heart failure. Despite maximal medical therapy and a biventricular pacemaker, the patient continued to have worsening heart failure with end-organ dysfunction. He was subsequently referred for evaluation for heart transplantation. A standard transplant evaluation was completed. Due to clinical worsening, an intraaortic balloon pump was placed. An LVAD was believed to be indicated as a bridge to transplantation.
The patient underwent placement of a HeartMate I LVAD (Thoratec, Pleasanton, CA). At operation, cardiopulmonary bypass was instituted, an aortic cross clamp was placed, and cardioplegia was administered. A transverse aortotomy was created in order to access the mechanical valve. Inspection verified it to be a Medtronic-Hall aortic prosthesis. Closure of the valve was accomplished with a horizontal mattress stitch using 2-0 Ethibond (braided polyester) suture (Ethicon, Somerville, NJ). A 5-mm bite was taken on the aortic side of the valve-sewing ring. A second bite was taken on the opposite side of the sewing annulus, 180° from the first bite. The suture was then tied over the aortic side of the valve. The stitch was oriented perpendicular to the axis of rotation of the valve disk (Fig 1). An LVAD implantation was completed in standard fashion, and the patient was weaned off of cardiopulmonary bypass. Intraoperative transesophageal echocardiogram demonstrated no flow across the prosthetic valve and no leaflet motion. Postoperatively the patient was anticoagulated. A transesophageal echocardiogram performed 1 month postoperatively showed no flow across the aortic valve again.
The patient's postoperative course was complicated by respiratory failure and renal failure. He was discharged home but expired 4 months after placement of his LVAD. Postmortem examination demonstrated the aortic prosthesis to be secured in the closed position, with a thin layer of thrombus present (1 mm).
Patient 2
A 51-year-old woman with a history of coronary artery bypass and aortic valve replacement with a St. Jude bileaflet prosthesis (St. Jude Medical, St. Paul, MN) had multiple hospitalizations for congestive heart failure. Her symptoms persisted despite maximal medical therapy, and she was eventually placed on the list for transplantation. Her condition worsened and placement of an LVAD as a bridge to transplantation was performed.
During the operation, the St. Jude prosthesis was identified through a transverse aortotomy. The valve leaflets, which were protruding into the ventricle when open, required the closing stitch to be placed on the ventricular aspect of the valve. A simple stitch using 2-0 Ethibond suture was placed by initially passing the suture through the sewing ring of the valve from the aortic to the ventricular side. The suture was then brought from the ventricular to the aortic side of the sewing annulus, opposite the first bite. The stitch was oriented perpendicular to the rotation axes of the valve leaflets (Fig 2). The aortotomy was then closed, and a Thoratec implantable ventricular assist device (IVAD) was placed in standard fashion. Transesophageal echocardiogram was performed (after weaning from cardiopulmonary bypass) showed no flow across the valve and no leaflet motion. The patient was anticoagulated postoperatively. Transesophageal echocardiogram was performed 2 weeks after an implantable ventricular assist device was placed, which again showed no flow through the aortic valve prosthesis.
Three months after placement of her implantable ventricular assist device the patient underwent successful heart transplantation. Examination of the explanted heart demonstrated the valve leaflets to be immobile. In addition to this, the ventricular and aortic aspects of the valve were covered with a thin film of thrombus.
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Comment
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In patients with mechanical aortic prostheses, it is currently recommended that the mechanical valve be replaced with a bioprosthesis. Alternatively the aortic valve can be closed with a pericardial or Gore-Tex patch (W.L. Gore & Assoc). Although thrombus may potentially form at the site of the patch closure, the embolic risk has been low due to the absence of flow across the valve [2]. The functional results of our single stitch aortic prosthetic closure are similar to patch closure. It is unknown whether anticoagulation will be necessary in these patients. The patient with the Thoratec implantable ventricular assist device required anticoagulation with warfarin (Bristol-Myers Squibb, Plainsboro, NJ) for her device. Aspirin therapy alone may have been sufficient for our patient with the HeartMate I LVAD. Because the aortic face of the valve is exposed to low flow blood and is not excluded as in the patch-closure method, thrombus can potentially form on the aortic side of the valve. However, in the absence of leaflet motion, the risk of a thromboembolic event may be quite low. Currently, there is no literature stating the embolic risk after valve closure.
We found that a simple horizontal mattress in a single plane to prevent a tilting-disk valve from opening and a simple suture across the sewing ring for a bi-leaflet valve are relatively simple solutions in comparison with previously described techniques. A braided polyester suture was utilized based on the surgeon's preference. Its long-term tensile strength and resistance to infection are similar to polypropylene (Ethicon Inc, Somerville, NJ), which can be alternatively used [4, 5].
In conclusion, closure of a mechanical aortic prosthesis with a single stitch is a simple and effective approach to minimize ischemic time and cardiopulmonary bypass time in patients with mechanical aortic valves that require ventricular assist device support.
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References
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- McCarthy PM, Smedira NO, Vargo RL, et al. One hundred patients with the HeartMate left ventricular assist deviceevolving concepts and technology. J Thorac Cardiovasc Surg 1998;114:904-912.
- Savage EB, d'Amato TA, Magovern JA. Aortic valve patch closurean alternative to replacement with HeartMate LVAS insertion. Eur J Cardiothoracic Surg 1999;16:359-361.[Abstract/Free Full Text]
- Rao V, Slater JP, Edwards NM, Naka Y, Oz MC. Surgical management of valvular disease in patients requiring left ventricular assist device support Ann Thorac Surg 2001;71:1448-1453.[Abstract/Free Full Text]
- Scher KS, Berstein JM, Jones CW. Infectivity of vascular sutures Am Surg 1985;51:577-579.[Medline]
- Greenwald D, Shumway S, Albear P, Gottlieb L. Mechanical comparison of 10 suture materials before and after in vivo incubation J Surg Res 1994;56:372-373.[Medline]
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Abstract
Introduction
