Ann Thorac Surg 2007;83:1904-1905
© 2007 The Society of Thoracic Surgeons
How To Do It
Transaortic Delivery of the Transmitral Lesion in a Complete Maze Procedure
Lucian Lozonschi, MDa,b,
John H. Sirak, MDa,b,
Robert E. Michler, MDa,b,*
a Department of Cardiothoracic Surgery, Ohio State University Medical Center, Columbus, Ohio
b Department of Cardiothoracic Surgery, Montefiore Medical Center/Albert Einstein College of Medicine, New York City, New York
Accepted for publication July 6, 2006.
* Address correspondence to Dr Michler, Department of Cardiothoracic Surgery, Montefiore-Einstein Heart Center, Montefiore Medical Center, Greene Medical Arts Pavilion Suite 5B, 3400 Bainbridge Ave, New York, NY 10467 (Email: rmichler{at}montefiore.org).
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Abstract
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A 68-year-old hypertensive diabetic woman with chronic atrial fibrillation presented with progressive congestive symptomatology. She was diagnosed with severe aortic stenosis, moderate mitral regurgitation, and critical right coronary artery stenosis. In addition to coronary revascularization and bioprosthetic aortic valve replacement, she underwent a mitral valve repair and a complete cryoMaze procedure through a transaortic approach. This technique obviates a separate left atriotomy for the mitral repair and Maze procedure. It affords excellent exposure, while reducing cross clamp and cardiopulmonary bypass time as well as avoiding the potential sequelae of bleeding and traction injuries resulting from a left atriotomy.
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Introduction
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Atrial fibrillation is the most common, dangerous, and costly cardiac dysrhythmia [1]. Pulmonary vein isolation delivered by an epicardial or catheter-based approach achieves a cure in 80% to 90% of patients with paroxysmal atrial fibrillation [2]. However, with permanent atrial fibrillation, pulmonary vein isolation results in only a 50% long-term freedom from relapse [2]. Effective ablative treatment of permanent atrial fibrillation requires the addition of a lesion connecting the left pulmonary veins to the mitral annulus.
No reports to date describe placement of the transmitral lesion without a standard left atriotomy. The transaortic approach has been described for both repair and replacement of the mitral valve in complex reoperative procedures involving the aortic root [3, 4]. The associated advantages of decreased operative trauma and cardiopulmonary bypass time result from obviating the additional cardiotomy required for left atrial exposure.
Herein we describe a transaortic approach to achieve a complete cryoMaze procedure and mitral valve repair in an elderly patient undergoing a concomitant aortic valve replacement and single-vessel coronary revascularization.
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Technique
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After the induction of general endotracheal anesthesia, the relevant valvular pathology was evaluated by transesophageal echocardiography. Cardiopulmonary bypass was established through a standard aortic and bi-caval cannulation. The left ventricle was vented through a catheter introduced into the left superior pulmonary vein. Cardiac arrest was obtained through the administration of antegrade and retrograde cold blood cardioplegia. The distal coronary anastomosis was first completed using a segment of reversed saphenous vein to permit additional doses of cardioplegia to be delivered directly into the distal vessel.
Using the SurgiFrost 10 cryosurgical probe (CryoCath Technologies Inc, Montreal, Quebec, Canada), epicardial ablations were delivered to encircle the pulmonary veins at their junction with the left atrium and to connect the left atrial appendage with the left pulmonary veins. The duration of each application was approximately 60 seconds, and was dependent on the rapidity of achieving a tissue temperature of –100°C. When this threshold temperature was reached within 15 seconds, a 30-second lesion was performed for a total lesion time of approximately 45 seconds. When this threshold temperature was reached within 30 seconds, a 45-second lesion was performed for a total lesion time of approximately 75 seconds. Threshold temperatures where always reached within 30 seconds. All left-sided and right-sided lesions were accomplished within the period of a single dose of cardioplegia, which by our convention was 20 minutes.
The aortic valve was then exposed through a transverse aortotomy. The calcified, stenotic aortic valve was excised, followed by debridement of the annulus. The anterior leaflet of the mitral valve was then elevated with a vein retractor and the flexible cryosurgical probe was readily passed through the aortic annulus and positioned to deliver the critical lesion connecting the mitral annulus to the left pulmonary veins under direct vision (Fig 1). Next, a connecting lesion was performed to the left followed by the right pulmonary veins.
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Fig 1. Schematic representation illustrating positioning of a flexible cryosurgical probe through the aortic annulus to deliver the critical lesion connecting the mitral annulus to the left pulmonary veins.
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An Alfieri edge-to-edge mitral valvuloplasty repair was then performed using a single horizontal mattress monofilament suture. The suture was positioned so as to connect the midpoints A2 and P2 segments of the anterior and posterior mitral leaflets. The prosthetic aortic valve was inserted and the aortotomy was closed. The proximal anastomosis of the saphenous vein graft was completed to the ascending aorta. The aortic cross clamp was removed after 82 minutes after its application in this case. The patient was then rewarmed.
With the vena cavae ensnared with tourniquets and the retrograde catheter removed, the SurgiFrost probe (CryoCath Technologies Inc) was passed through the pursestring suture used for the retrograde catheter to create the standard Maze III lesions, including the inferior endocardial lesion across the tricuspid valve and the cryolesion connecting the tricuspid annulus to the inferior vena cava. Epicardial applications were linearly performed to connect the superior and inferior vena cavae from the right atrial appendage to within 3 cm of the "T" lesion and across the coronary sinus. Therefore a complete cryoMaze III procedure was performed, including all lesion sets [5].
The patient was weaned from cardiopulmonary bypass. Intraoperative transesophageal echocardiography and electrocardiographic measurements confirmed trivial mitral regurgitation, normal aortic prosthetic valve function, and normal sinus rhythm. An echocardiogram performed on postoperative day 5 showed mild (1+) mitral regurgitation while the patient remained in sinus rhythm and without new symptoms at 1 month and subsequently 3 months after her discharge.
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Comment
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Sustained efficacy of antiarrhythmic procedures in eliminating permanent atrial fibrillation requires the inclusion of the lesion connecting the mitral annulus to the pulmonary veins. Currently this lesion may be reliably delivered only by an endocardial application. In this case report, a transaortic approach provides excellent exposure for left atrial cryoablation as well as a mitral valve edge-to-edge repair in a patient with moderate mitral regurgitation in the setting of a stenotic aortic valve. More severe mitral regurgitation would have necessitated a left atriotomy and standard repair techniques.
The approach described for this case obviates the additional operative trauma, cross-clamp time, and cardiopulmonary bypass time required to expose the left atrium through a separate left atriotomy, particularly in a patient of advanced age. This consideration clearly increases in importance in reoperative procedures and more complex operations, but is limited to patients without severe mitral valve regurgitation and pathology.
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References
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- Feinberg WM, Blackshear JL, Laupacias A, Kronmal R, Hart RG. Prevalence, age distribution, and gender of patients with atrial fibrillation: analysis and implications Arch Intern Med 1995;155:469-473.[Abstract/Free Full Text]
- Gillinov AM, McCarthy PM, Blackstone EH, et al. Surgical ablation of atrial fibrillation with bipolar radiofrequency as the primary modality J Thor Cardiovasc Surg 2005;129:1322-1329.[Abstract/Free Full Text]
- Kallner J, van der Linden J, Hadjinikolaou L, Lindblom D. Transaortic approach for the Alfieri stitch Ann Thor Surg 2001;71:378-379.[Abstract/Free Full Text]
- Najafi H, Hemp J. Mitral valve replacement through the aortic root J Thor Cardiovasc Surg 1994;107:1334-1336.[Abstract/Free Full Text]
- Cox JL, Ad N. New surgical and catheter-based modifications of the Maze procedure Semin Thorac Cardiovasc Surg 2000;12:68-73.[Medline]
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Abstract
Introduction
