Ann Thorac Surg 2000;69:646-647
© 2000 The Society of Thoracic Surgeons
How to Do It
Exposure of the mitral valve by transecting the ascending aorta during aortic and mitral valve replacement
V.R. Machiraju, MDa,
Claudio A.B. Lima, MDa,
Michael H. Culig, MDa,
Robert D. Bennett, MDa,
Navin S. Thakur, MDa
a Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
Address reprint requests to Dr Machiraju, Division of Thoracic Surgery, Shadyside Hospital, 5200 Center Ave, Pittsburgh, PA 15232
e-mail: rajca{at}ssh.edu
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Abstract
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Combined aortic and mitral valve operations are still considered major cardiac surgical procedures. The duration of aortic cross-clamping and cardiopulmonary bypass is longer, which increases morbidity and mortality for these combined, complicated operations. Aortic valve exposure is generally satisfactory, but mitral valve exposure may be difficult and add to the length of the aortic cross-clamping time [1]. We have exposed the mitral valve by transecting the ascending aorta, and retracting both ends apart, to give direct access through the dome of the left atrium in 7 patients. This approach gave good exposure and did not increase the risk of complications. Exposure of the mitral valve through the left atrium using a superior approach, by transecting the ascending aorta, is a good option for patients with multiple cardiac conditions who are undergoing combined aortic and mitral valve operations.
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Introduction
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At present we have used this technique in 7 patients. All of these patients required aortic and mitral valve surgical procedures. Three patients required valve operations after previous coronary artery bypass, whereas 4 patients underwent primary cardiac surgical procedure without previous operation. Three patients required additional coronary artery bypass; 1 required ascending aortic aneurysm resection, 1 patient required aortic root replacement, and the third patient required septal myomectomy.
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Operative technique
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In all the patients, the standard cardiopulmonary bypass is instituted through median sternotomy. Aortic cannulation is performed using a soft-flow extended aortic cannula (3M Sarns 4951; Sarns 3M Health Care, Ann Arbor, MI) into the distal aortic arch for antegrade perfusion. Two separate cannulas were used in the superior vena cava and the right atrium (Medtronic DLP 66120 20F and 67522 22F, respectively; Medtronic DLP, Grand Rapids, MI) for venous drainage. A coronary sinus catheter is placed in every case for retrograde cardioplegic delivery. Antegrade cardioplegia is administered after aortic cross-clamping, whenever there is no aortic insufficiency. Retrograde perfusion is used in such cases and also when there are patent vein grafts.
Our standard procedure is mild hypothermia with body temperature ranging from 33°C to 35°C and cardioplegic temperature at 30°C. Continuous retrograde blood mini (micro) cardioplegia is administered at 100 cc a minute continuously, except for 1 or 2 minute brief interruptions. Cardioplegic agents included K+ and magnesium only.
Bicaval tapes were never used in these cases, unless the right atrium had to be opened for tricuspid repair. The focus of surgical dissection is centered on the ascending aorta (Fig 1). After complete dissection, the ascending aorta is transected above the sinotubular junction. The aortic valve was excised, a vent is placed into the left ventricle through the aortic root, and both ends of the aorta are retracted apart (Fig 2). Then the dome of the left atrium is opened to a length to 2 to 2.5 inches. A Cosgrove retractor (Kapp Surgical Inst, Cleveland, OH) has been placed and the mitral valve is exposed. Occasionally, the superior edge of the left atrium is blocking the vision, a vertical incision is made for better visibility towards the pulmonary artery.
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Fig 1. Ascending aorta is transected, and both ends of the aorta are retracted apart. A vent is placed into the left ventricle through the proximal aorta.
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Fig 2. Mitral valve is exposed, using the Cosgrove retractor, through the superior approach by opening the dome of the left atrium.
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Because of direct exposure of the mitral valve without any obstruction of the view, the surgical procedure can be done much quicker than usual, and this has certainly decreased the cross-clamp time. Although the length of aortic cross-clamping depends on various factors, ease of mitral valve operation has been the consistent finding through this exposure. After the contemplated procedure has been done, left atriotomy is closed in two layers. A pledgett 4-0 Prolene (Ethicon, Somerville, NJ) suture has been used in both corners of the left atriotomy securing the corners. A horizontal mattress suture is initially run through the left atrium, and an over and over suture was used with these Prolene sutures. This has consistently given adequate closure, with no tears in the left atrium or bleeding from the atriotomy. After the atriotomy is closed, aortic valve operation is done, and both ends of the ascending aorta are brought together and closed back with 4-0 Prolene, reinforced with Teflon (Impra Inc, a subsidiary of L. R. Bard, Tempe, AZ) felt circumferentially. After closure of the aortotomy, an aortic root vent is placed. The aortic root vent is left after the cross-clamp is released and after the patient is off cardiopulmonary bypass until all the air is evacuated as judged by the transesophageal echocardiogram.
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Comment
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Adequate exposure of the mitral valve is the key to successful repair or replacement [2, 3]. Satisfactory exposure of the mitral valve is facilitated by retracting on vena cavae, extending transseptal approach, transection of the superior vena cava, and transection of the azygos vein [4, 5].
Recently, Gundry and colleagues described an upper median sternotomy for double valve replacement, using the superior approach, through the dome of the left atrium, by retracting the ascending aorta. [6]. Visualization of the valve depends upon the degree of retraction of the aorta. Double valve replacement certainly remains a challenge, and transection of the aorta instead of subtotal transverse aortotomy would facilitate better exposure of the mitral valve. It has been accepted to transect the aorta while performing stentless valve implantation, and this approach can be used in double valve replacement as well [7].
The main technical considerations in performing the procedure are as follows: (1) Closure of left atriotomy. One of the general concerns is limited area for the left atriotomy incision. In a few cases where the transverse atriotomy has not given exposure, we had made an inverted T-incision on the atrium, making a vertical incision towards the pulmonary artery. This has given full exposure of the valve. While making the left atriotomy, care is taken not to make the incision too close to the aortic root. There should be a portion of the left atrium on both sides of the atriotomy, which helps the retractor to pull on the left atrium. (2) Venting the left ventricle. After the availability of this small intracardiac pool sucker (Mueller CH-8000-058 intracardiac sucker; Baxter V Mueller Products, Baxter Health Care Corp, Deerfield, IL) we have virtually stopped dissecting down the superior pulmonary vein for venting. Transaortic decompression of the ventricle with this pool sucker has helped in every case and minimized our dissection. (3) Lastly, if we need to reexpose the mitral valve after coming off bypass after a double valve surgical procedure, the surgeon must determine whether he wants to reopen the atriotomy suture line, by retracting the aorta, or remove the aortic suture line and resuture the aorta after the problem in the mitral valve is addressed.
Our experience shows that direct exposure of the mitral valve by transecting the aorta provides minimal mediastinal dissection, which automatically translates into less postoperative bleeding, and therefore minimal morbidity.
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References
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McCarthy J.F., Cosgrove D.M., III Optimizing mitral valve exposure with conventional left atriotomy. Ann Thorac Surg 1998;65:1161-1162.[Abstract/Free Full Text]
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Meyer B.W., Verska J.J., Lindensmith G.G., Jones J.C. Open repair of mitral valve lesions. Ann Thorac Surg 1965;1:453-457.
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Balasundaram S.G., Duran C. Surgical approaches to the mitral valve. J Cardiac Surg 1990;5:163-169.[Medline]
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Guiraudon G.M., Ofiesh J.G., Kaushik R. Extended vertical transatrial septal approach to the mitral valve. Ann Thorac Surg 1991;52:1058-1062.[Abstract]
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Frank M.W., Stout M.J. Optimizing mitral valve exposure with azygous vein ligation. Ann Thorac Surg 1999;67:1536-1544.[Free Full Text]
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Gundry S.T., Shattuck O.H., Razzouk A.J., del Rio M.J., Sardari F.F., Bailey L.L. Facile minimally invasvie cardiac surgery via ministernotomy. Ann Thorac Surg 1998;65:1100-1104.[Abstract/Free Full Text]
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Del Rizzo D.F., Goldman B.S., David T.E., Canadian Investigators of the Toronto SPV Valve Trial. Aortic valve replacement with a stentless porcine bioprosthesis. Can J Cardiol 1999;11:597-603.
Accepted for publication October 18, 1999.
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Abstract
Introduction
