Ann Thorac Surg 2006;82:2280-2282
© 2006 The Society of Thoracic Surgeons
Case Reports
Pseudoaneurysm of an Aortic Homograft
Gonçalo F. Coutinho, MD,
Manuel J. Antunes, MD, PhD*
Cardiothoracic Surgery, University Hospital, Coimbra, Portugal
Accepted for publication April 4, 2006.
* Address correspondence to Dr Antunes, Centro de Cirurgia Cardiotorácica, Hospitais da Universidade, Coimbra, 3049 Portugal. (Email: antunes.cct.huc{at}sapo.pt).
 |
Abstract
|
|---|
False aneurysms of the thoracic aorta constitute one of the most challenging problems encountered by the cardiac surgeon. We report a case of successful reoperation for a giant pseudoaneurysm of an aortic homograft, previously used in the context of postpartum acute endocarditis of the aortic valve.
|
Introduction
|
|---|
Postoperative pseudoaneurysms of the aorta (PSA) are rare complications of cardiovascular procedures and are usually related to the cannulation and vent sites, aortotomy and anastomotic suture lines, or cross-clamping site [1]. They are initiated by a small disruption of the vessel wall that allows blood to leak into the surrounding space. A number of variables are responsible, including elevated pressure at the anastomotic site, poor viability of the residual vessel or muscular tissue bordering the homograft, progressive vascular disease, infection, and the suture technique or material used or both. The walls of the PSA are composed of fibrin and pericardium and by definition, they contain no myocardial elements. They can have catastrophic consequences, including rupture, infection, embolism, and compression of surrounding structures.
We report a case of a 45-year-old woman submitted to emergency surgery for acute endocarditis of the aortic valve (Staphylococcus epidermidis) 11 years previously at another institution. During that surgery, the aortic valve was translocated with interposition of a cryopreserved aortic homograft, and the coronary ostia were ligated. Three coronary artery bypasses with saphenous vein grafts were performed for each coronary territory (left anterior descending coronary artery, obtuse marginal coronary artery, posterior descending coronary artery).
She remained only mildly symptomatic (ie, functional class 1–2 of the New York Heart Association) until 9 years postoperatively, when she had several hospitalizations for episodes of paroxysmal atrial fibrillation that required electric cardioversion. During complementary evaluation, a large PSA of the aortic root showing a communication between an extracardiac echographic-free space and the left ventricular outflow tract (LVOT) with a slow systo-diastolic color Doppler signal and moderate aortic regurgitation was detected by transesophageal echocardiography. An angiographic computed tomographic scan and an angiographic magnetic resonance scan were done, confirming the existence of a PSA (largest diameter, 110 mm) with a large neck (40 mm) communicating with the LVOT. It was located on the left side, behind and beneath the pulmonary trunk and the left pulmonary artery, and above the left atrium, extending posteriorly toward the descending aorta. The left pulmonary hilum structures were deviated backwards and upwards by the extrinsic compression caused by the aneurysm (Fig 1). Cardiac catheterization was carried out for evaluation of the 11-year-old vein grafts, which did not show signs of atherosclerotic disease or anastomotic stenosis. The homograft wall was completely calcified and there was no transaortic gradient, but moderate aortic regurgitation was visualized. The left ventricular function was preserved.
View larger version (71K):
[in this window]
[in a new window]
|
Fig 1. Three different images of an angiographic magnetic resonance study showing a very large pseudoaneurysm (110 mm) originating in the left ventricular outflow tract, with a large neck (40 mm) (left), compressing the left pulmonary hilum structures (center), and extending posteriorly towards the descending aorta (right).
|
|
The patient was referred to our institution for a second opinion, after having been refused an operation or proposal for a heart transplant at two other institutions, because of the high risk involved. We decided to proceed to perform corrective surgery on the basis of the risk of rupture, infection, and compression of the surrounding structures, enlarging the left ventricle with preserved function, moderate aortic regurgitation, and the young age and good condition of the patient.
During surgery, a median sternotomy was performed and the patient was placed on cardiopulmonary bypass after cannulation of the proximal aortic arch and right atrial appendage. A left ventricular decompression vent was used and the patient was cooled to 25°C. Cold crystalloid cardioplegia was administered antegradely through a catheter placed successively in the orifice of each of the three saphenous vein grafts after entering the calcified homograft. The PSA was entered by the roof and the large neck communicating with the LVOT was visualized. There were no signs of infection and the walls of the PSA were covered by fibrous tissue suggesting chronic evolution. The LVOT was reconstructed using a Gore-Tex membrane patch (W. L. Gore & Assoc, Flagstaff, AZ) from the left ventricular side of the anastomosis sutured with Gore-Tex sutures. The aortic root and ascending aorta were replaced with a composite Dacron (Boston Scientific, Natick, MA) graft and mechanical prosthesis as a modified Bentall technique. The residual cavity of the aneurysm was left open to the pericardium. The bypass for the posterior descending artery was rebuilt with proximal interposition of a small segment of saphenous vein, and the other grafts were reimplanted directly into the conduit. A pedicled left internal mammary artery was anastomosed distally to the dorsum of the saphenous vein graft anastomosis to the left anterior descending coronary artery.
|
Comment
|
|---|
Since an allograft aortic valve was first implanted in a clinical setting, improvements in surgical technique and preservation methods have propelled the allograft to the forefront of complex LVOT reconstruction, especially in native and prosthetic valve endocarditis [2]. But this conduit is not completely exempt of complications. The singularity of the case we report herein is related not only to the existence of this bulky PSA, but to the challenging surgical decisions that had to be taken regarding the therapeutic options made in the first surgery, such as the ligation of both coronary arteries.
Although redo aortic root replacement may be a complex procedure with a reported high mortality rate (15% to 40%), it can be done with reasonable safety if the procedure is well prepared, taking into account all the possible scenarios that may arise during surgery [3, 4]. Three aspects were of paramount importance: (1) approach to the PSA—redo sternotomy (and redo aortic root replacement); site of cannulation; need for deep hypothermic circulatory arrest; (2) management of the coronary circulation—risk of injury to the grafts; need for replacement of the venous grafts; (3) reconstruction of the LVOT (large neck of the aneurysm).
Although the majority of the reports concerning the strategy for the best approach to a pseudoaneurysm consider the femoro-femoro or femoro-subclavian cannulation with total or partial circulatory arrest [5, 6], we believed that for this specific case a classical cannulation (ie, aortic arch and right atrial appendage) could be safely performed, because the aneurysm was proximal and in a posterior position, and the risk of entering it during re-sternotomy was minimal. In this respect, the importance of a complete and thorough imagiologic study characterizing the PSA and surrounding structures outweighed any "guidelines" that exist in the literature [7, 8].
Regarding the management of the previously placed venous grafts, any decision would always be arguable because of the well known low long-term patency rates of venous grafts, and this patient’s grafts had been in place for 11 years. Our option not to replace the grafts was based on the fact that the patient had no signs of atherosclerotic coronary artery disease and the grafts were widely open. However, the decision to use the left internal mammary artery in the left anterior descending coronary artery territory was made as a precaution measure because of its high late patency rate.
Finally, there were not any doubts about the need to rebuild the LVOT, because the neck of the PSA was large and caused distortion. Care was taken when directing the patch to the aortic root because the valved conduit had to be partially implanted on it.
In conclusion, we report a case of successful reoperation for a giant PSA of an aortic homograft previously placed in the context of postpartum acute endocarditis of the aortic valve. Perfect knowledge of the anatomy and carefully planned surgery made for a relatively trouble-free procedure and excellent result.
|
References
|
|---|
- Razzouk A, Gundry S, Wang N, et al. Pseudoaneurysms of the aorta after cardiac surgery or chest trauma Am Surg 1993;59:818-823.[Medline]
- Camacho MT, Cosgrove DM. Homografts in the treatment of prosthetic valve endocarditis Semin Thorac Cardiovasc Surg 1995;7:32-37.[Medline]
- Raanani E, David TE, Dellgren G, Armstrong S, Ivanov J, Feindel CM. Redo aortic root replacement: experience with 31 patients Ann Thorac Surg 2001;71:1460-1463.[Abstract/Free Full Text]
- LeMaire SA, DiBardino DJ, Köksoy C, Coselli JS. Proximal aortic reoperations in patients with composite valve grafts Ann Thorac Surg 2002;74:S1177-S1180.
- Mohammadi S, Bonnet N, Leprince P, et al. Reoperation for false aneurysm of the ascending aorta after its prosthetic replacement: surgical strategy Ann Thorac Surg 2005;79:147-152.[Abstract/Free Full Text]
- Dumont E, Carrier M, Cartier R, et al. Repair of aortic false aneurysm using deep hypothermia and circulatory arrest Ann Thorac Surg 2004;78:117-121.[Abstract/Free Full Text]
- Katsumata T, Moorjani N, Vaccari G, Westaby S. Mediastinal false aneurysm after thoracic aortic surgery Ann Thorac Surg 2000;70:547-552.[Abstract/Free Full Text]
- Oechslin E, Carrel T, Attenhofer CH, et al. Pseudoaneurysm following aortic homograft: clinical implications? Br Heart J 1995;74:645-649.[Abstract/Free Full Text]
Top
Abstract
Introduction
