J Thorac Cardiovasc Surg 2009;137:247-249
© 2009 The American Association for Thoracic Surgery
Repair of acute postinfarction atrioventricular dehiscence in a patient with posterior left ventricular aneurysm
Igor E. Konstantinov, MD, PhD*,
Pankaj Saxena, MCh, DNB,
Shane Ling, MB, BS,
Trenton Barrett, MB, BS
Department of Cardiothoracic Surgery, Sir Charles Gairdner Hospital, University of Western Australia, Perth, Australia
Received for publication January 26, 2008; revisions received February 13, 2008; accepted for publication February 23, 2008.
* Address for reprints: Igor E. Konstantinov, MD, PhD, Department of Cardiothoracic Surgery, Sir Charles Gairdner Hospital, Perth, WA 6009, Australia. (Email: konstantinov.igor{at}alumni.mayo.edu).
Acute postinfarction atrioventricular (AV) dehiscence is a rare complication. If the dehiscence is contained, it may form a pseudoaneurysm. The pseudoaneurysm has little strength and is prone to rupture. Left ventricular (LV) pseudoaneurysm is most commonly located at the posterior basal segment, where it is likely to be contained. Repair of postinfarction LV pseudoaneurysm is associated with 20% to 35.7% mortality even in the modern era.1-3
We can report the successful management of an acute postinfarction AV dehiscence in a patient with a true posterior LV aneurysm and severe mitral insufficiency.
Clinical Summary
A 57-year-old diabetic woman had a non-ST elevation myocardial infarction and pulmonary edema. Echocardiography demonstrated severe mitral insufficiency resulting from tethering of the posterior leaflet at P2 and P3 segments, LV ejection fraction of 34%, a true posterior LV aneurysm, and severe calcification of the posterior mitral annulus with an AV dehiscence and a pseudoaneurysm. Magnetic resonance imaging confirmed the findings and delineated an AV dehiscence of 5 mm in diameter that formed an entry into a pseudoaneurysm (
Figure 1, A) dissecting into the AV groove. The pseudoaneurysm was 22 x 18 mm and was contained by coronary sinus and epicardial fat (Figure 1, A and B). A coronary angiogram demonstrated triple-vessel coronary artery disease. An intra-aortic balloon pump was placed before urgent surgery. After median sternotomy, cardiopulmonary bypass was established with aortic and bicaval cannulation. Three coronary arteries were bypassed with vein grafts. To expose the entry into the pseudoaneurysm (
Figure 2, A), we detached the posterior leaflet of the mitral valve and resected a portion of the severely calcified posterior mitral annulus. A large bovine pericardial patch was sutured to the base of the papillary muscles, posterior LV wall, and left atrium to exclude the area of dehiscence (Figure 2, B). All native chords were preserved and plicated to the mitral annulus. Additional 4–0 polytetrafluoroethylene (PTFE) chords (Gore-Tex; W. L. Gore & Associates, Inc, Flagstaff, Ariz) were placed to relieve tension on the pericardial patch (Figure 2, B and C). The mitral valve was replaced with a 29-mm ATS prosthesis (ATS Medical Inc, Minneapolis, Minn). The PTFE chords were anchored to the sewing ring of the prosthesis (Figure 2, C). Aortic crossclamp time was 150 minutes. Cardiopulmonary bypass time was 254 minutes. The postoperative course was uncomplicated. Postoperative echocardiography demonstrated an LV ejection fraction of 46%. The patient is doing well at 3 months' follow-up.
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Figure 1. Magnetic resonance image demonstrated an AV dehiscence with detachment of the posterior mitral annulus and entry into a pseudoaneurysm (A) and contained in AV groove (A and B).
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Figure 2. Severely calcified posterior mitral valve annulus formed a bridge above the entry into the pseudoaneurysm (A). The calcified portion of posterior mitral annulus is resected, the atrium is reattached to the ventricle by the bovine pericardial patch, and the attachment is re-enforced by plicated native chords and PTFE neochords (B). Mitral valve replacement is performed and PTFE chords are anchored to the sewing ring of the prosthesis (C). Pledgets of autologous pericardium are used to reinforce PTFE chordals attachment to the papillary muscles (B and C).
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Discussion
An unusual feature in our patient was an AV dehiscence as a result of acute basal infarction in a setting of a chronic true posterior LV wall aneurysm and severe ischemic mitral insufficiency. The exact cause of this rare condition is unknown. One may speculate, however, that an acute myocardial infarction at the base of the ventricle further weakened the posterior LV wall, which was already under stress owing to the existing LV aneurysm, and resulted in AV dehiscence. An impending rupture necessitated urgent surgery. We believe that intra-aortic balloon pump placement was beneficial in decreasing LV pressures and minimizing the risk of acute rupture.
The mortality in patients undergoing postinfarction pseudoaneurysm repair is high and long-term survival is poor.1-3 Such poor outcome is related mainly to poor postoperative LV function, rather than to technical difficulties during repair.2,3 We believe that achieving a tension-free connection of the left atrium to the LV is crucial for successful repair. Such tension-free connection is best achieved by application of a bovine pericardial patch sutured to the mitral annulus. The patch can be placed either via the posterior LV incision, as previously described by one of us,4 or via the mitral valve orifice.5 Endocavitary placement of the pericardial patch seals the entry point into the pseudoaneurysm, stabilizes the AV connection, and relieves the tension from the posterior LV wall, preventing postoperative bleeding owing to LV wall rupture. Furthermore, preservation of the chordal apparatus is crucial for LV function. Preservation of all chords combined with papillary muscle resuspension with the PTFE chords and myocardial revascularization resulted in significant improvement of LV function in our patient.
Acute postinfarction AV dehiscence is a challenging problem. Prompt surgical management, however, can achieve a successful outcome.
References
- Frances C, Romero A, Grady D. Left ventricular pseudoaneurysm. J Am Coll Cardiol 1998;32:557-561.[Abstract/Free Full Text]
- Eren E, Bozbuga N, Toker ME, Keles C, Rabus MB, Yildirim O, et al. Surgical treatment of post-infarction left ventricular pseudoaneurysm: a two decade experience. Tex Heart Inst J 2007;34:47-51.[Medline]
- Atik FA, Navia JL, Vega PR, Gonzalez-Stawinski GV, Alster JM, Gillinov AM, et al. Surgical treatment of postinfarction left ventricular pseudoaneurysm. Ann Thorac Surg 2007;83:526-531.[Abstract/Free Full Text]
- Konstantinov I, Mickleborough LL, Graba J, Merchant N. Intraventricular mitral annuloplasty technique for use with repair of posterior left ventricular aneurysm. J Thorac Cardiovasc Surg 2001;122:1244-1247.[Free Full Text]
- Tarrio RF, Martinell MJ, Moya GJ, Calderon RP. Endocavitary patch repair for a left ventricular pseudoaneurysm: an alternative approach. J Card Surg 2005;20:278-280.[Medline]
