Ann Thorac Surg 2004;77:2197-2199
© 2004 The Society of Thoracic Surgeons
Case report
Giant anastomotic pseudoaneurysm complicating aortic xenograft replacement
Nils Kucher, MDa,
Beat Kipfer, MDb,
Christian Seiler, MD, FACC, FESCa,
Yves Allemann, MD, FESCa*
a Cardiology, Swiss Cardiovascular Center, Bern University Hospital, Bern, Switzerland
b Cardiovascular Surgery, Swiss Cardiovascular Center, Bern University Hospital, Bern, Switzerland
Accepted for publication June 6, 2003.
* Address reprint requests to Dr Allemann, Department of Cardiology, Swiss Cardiovascular Center, Bern University Hospital, 3010 Bern, Switzerland
e-mail: yves.allemann{at}insel.ch
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Abstract
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A 74-year-old woman was referred for investigation of a 2-week history of progressive dyspnea. Her medical history included an aortic valve replacement with a stentless bioprosthesis followed 13 months later by the replacement of the aortic root with a porcine xenograft. Transesophageal echocardiography revealed a giant circular pseudoaneurysm of the aortic xenograft with compression of the prosthetic aortic valve and concomitant severe aortic regurgitation. Dehiscence of the proximal graft anastomosis was also diagnosed, and a possible distal anastomotic dehiscence was suspected. The latter turned out intraoperatively to be an almost complete dehiscence of the right coronary artery. The patient died intraoperatively.
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Introduction
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Although a rare complication, true and false aneurysms are predominant indications for late reoperations after replacement of the ascending aorta or the aortic root. Reoperations on the ascending aorta and aortic root can be performed with a relatively low hospital mortality (<6%). Active endocarditis and vascular graft infections are independent predictors of in-hospital death.
A 74-year-old woman was referred to our outpatient clinic for investigation of a 2-week history of progressive dyspnea and orthopnea. Her medical history included aortic valve replacement for severe symptomatic aortic stenosis 2 years previously. Contraindication for anticoagulation and the possibility for patient–prosthesis mismatch (body surface area of 1.81 m2, body mass index of 33.3, and an intraoperatively measured annulus of 21 mm) were strong arguments for the implantation of a stentless bioprosthesis. Thirteen months later, the patient was reoperated because of the suspicion of a low-grade infection involving both the bioprosthesis and the ascending aorta with consecutive dysfunction of the aortic prosthesis. The aortic root was replaced with a 21-mm porcine xenograft (Shelhigh Stentless Valve Conduit, NR-2000C; Shelhigh, Union, NJ). All tissue cultures were sterile, and prolonged antibiotic treatment was started.
On physical examination, body temperature was 36.5°C, supine blood pressure was 130/60 mm Hg, and heart rate was 65 beats per minute. Cardiac auscultation revealed a 2 to 3/6 ejection systolic murmur at the right parasternal precordium and basal crackles were heard on both lungs. Laboratory findings included normal white blood cell count and erythrocyte sedimentation rate. There was no bacterial growth in repetitive blood cultures. Chest roentgenogram showed enlarged heart size and moderate pulmonary congestion. Transesophageal echocardiography revealed a giant circular pseudoaneurysm of the aortic graft (Fig 1)
with compression of the prosthetic aortic valve and consecutive moderate-to-severe aortic regurgitation (Fig 2)
. Dehiscence of the proximal graft anastomosis was also diagnosed. Moreover, what was echocardiographically diagnosed as a possible distal anastomotic dehiscence, approximately at the level of the right coronary ostium, turned out intraoperatively to be an almost complete dehiscence of the right coronary artery (Fig 2).
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Fig 1. Transesophageal short-axis view showing the circular pseudoaneurysm (A) surrounding the xenograft. The compressed bioprosthetic tricuspid aortic valve is in the closed position. (LA = left atrium; RA = right atrium.)
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Fig 2. Transesophageal long-axis view showing the pseudoaneurysm (A), a moderate-to-severe aortic regurgitation (turbulent jet, large arrow), and the almost complete dehiscence of the right coronary artery with blood flowing (small arrow) from the xenograft (XG) into the pseudoaneurysm (A).
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The patient was scheduled for emergent replacement of the xenograft. A preoperatively performed computed tomographic scan revealed a close relationship between the aneurysm and the sternum. Therefore, the chest was opened during cardiopulmonary bypass using a short period of deep hypothermic arrest. Because of the fragility of the xenograft and the native aorta, we were forced to replace the pericardial conduit of the xenograft and the native ascending aorta, including the concave side of the aortic arch. The porcine valve was suspended in a Dacron graft that was anastomosed to the open aortic arch. Because of the friability of the tissue, reimplantation of the coronary ostia was impossible. All coronary territories were bypassed with either the left internal mammarian artery or vein grafts. The destroyed and partially detached coronary ostia did not allow proper myocardial protection; retrograde cardioplegia was performed through the coronary sinus combined with topical cooling. Weaning from cardiopulmonary bypass failed and the patient died intraoperatively.
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Comment
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Pseudoaneurysm is a rare but potentially lethal complication of aortic composite Dacron graft procedures; the complication is even more rare for xenograft procedures. It usually develops as a consequence of dehiscent suture lines at the anastomotic sites [1]. Depending on the location and rapidity of development of the anastomotic dehiscence, patients may be asymptomatic or present with cardiogenic shock [2]. The main causes of pseudoaneurysm formation include infections and cystic medial necrosis [3]. Echocardiography is accurate in the diagnosis of this harmful complication [1]. In the setting of prosthetic valve endocarditis, a valuable alternative surgical treatment to the one chosen in the present case is aortic root replacement with a cryopreserved allograft, if available [4].
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References
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- Barbetseas J., Crawford E.S., Safi H.J., et al. Doppler echocardiographic evaluation of pseudoaneurysms complicating composite grafts of the ascending aorta. Circulation 1992;85:212-222.[Abstract/Free Full Text]
- Albat B., Leclercq P.F., Messner Pellenc P., et al. False aneurysm of the ascending aorta following aortic valve replacement. J Heart Valve Dis 1994;3:216-219.[Medline]
- Doria E., Ballerini G., Pepi M. Giant anastomotic pseudoaneurysm after Bentall operation causing late postoperative cardiogenic shock. Ital Heart J 2001;2:627-630.[Medline]
- Sabik J.F., Lytle B.W., Blackstone E.H., Marullo A.G., Pettersson G.B., Cosgrove D.M. Aortic root replacement with cryopreserved allograft for prosthetic valve endocarditis. Ann Thorac Surg 2002;74:650-659.[Abstract/Free Full Text]
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Abstract
Introduction
