Ann Thorac Surg 2005;79:705-707
© 2005 The Society of Thoracic Surgeons
Case report
Pseudoaneurysm of Ascending Aorta After Aortic Valve Replacement
Bhawna Parihar, MCha,
Lalit S. D. Choudhary, MSa,
Andrew Philip Madhu, DNBa,
Mathew K. Alpha, MSa,
Roy Thankachen, MCha,
Vinayak Shukla, MCh, DNBa,*
a Department of Thoracic and Cardiovascular Surgery, Christian Medical College and Hospital, Vellore, India
Accepted for publication September 5, 2003.
* Address reprint requests to Dr Shukla, Department of Thoracic and Cardiovascular Surgery, Christian Medical College and Hospital, Vellore 632 004, India
shukla58{at}hotmail.com
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Abstract
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A pseudoaneurysm of the ascending aorta is an unusual and potentially fatal complication after aortic surgical procedures. A contrast computed tomographic scan is the investigation of choice. Surgical treatment is mandatory. We describe the successful management of a pseudoaneurysm of the ascending aorta by instituting femorofemoral bypass and achieving hypothermic circulatory arrest, which provided safe reentry and prevented an impending rupture.
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Introduction
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Mediastinal pseudoaneurysms are rare but life-threatening complications of thoracic aortic operations [1, 2]. Predisposing factors are the dissection of the native aorta, infection, connective tissue disorders, preoperative chronic hypertension, aortic calcification, and blowout of the aortotomy site [1].
A pseudoaneurysm of the ascending aorta can present as a pulsatile mass, angina due to graft compression, chest pain caused by local erosion, dysphagia, or stridor [2].
Redo operations for large pseudoaneurysms of the ascending aorta are a surgical challenge [3]. Sternal reentry alone can precipitate fatal hemorrhage or cerebral air embolism.
Instituting femorofemoral bypass and establishing hypothermic circulatory arrest is a well-known entity [4]. We stress this strategy, which helped us prevent an impending rupture and repair the defect.
We present the case of a 35-year-old man who had undergone aortic valve replacement for rheumatic aortic regurgitation using a number 27 Medtronic prosthetic aortic valve (Medtronic, Minneapolis, MN). He was readmitted 6 months later with an intermittently painful, pulsatile swelling over the upper third of the sternum that had appeared over a period of 1 month and had gradually increased in size to attain its present size of 8 x 10 cm (Fig 1).
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Fig 1. Lateral view of patient showing pulsatile erythematous swelling over the upper third of the sternum.
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A contrast computed tomographic (CT) scan showed a defect in the anterior wall of the ascending aorta 2.6 cm above the prosthetic valve from which a pseudoaneurysm was arising and eroding the sternum, with an extrathoracic component measuring 8 x 6.7 cm (Fig 2). A median sternotomy after hypothermic circulatory arrest was the strategy of choice [4].
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Fig 2. Contrast computed tomographic scan showing ascending aortic pseudoaneurysm eroding the sternum with an extrathoracic component.
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Femorofemoral bypass was instituted, and the patient was gradually cooled to 18°C. While cooling, the heart fibrillated twice. This was at 22°C. The patient reverted back to sinus rhythm each time by defibrillating externally. Because the heart was ejecting all throughout and the aortic valve was competent, distension was prevented. If by chance it had not reverted back to sinus, the plan was to open the chest on reduced flows and obtain digital control over the defect on the aorta. A vent would then have been placed in the pulmonary artery to decompress the left side of the heart. Mannitol, thiopentone, and methylprednisolone were used for cerebral protection. Hypothermic circulatory arrest was established. The patient was drained, and the swelling over the chest wall collapsed. The head end of the patient was lowered to prevent air embolism. The chest was opened through the previous scar. The extrathoracic component of the pseudoaneurysm was opened and the clots evacuated. A sternotomy was then performed. Adhesions over the right ventricle were taken down, and both pleura were opened. Clots in front of the aorta were evacuated to reveal 1 main and 2 adjacent defects at the previous aortotomy site, which were converted into a single defect measuring 2 x 2 cm (Fig 3). The prosthetic valve was palpated through the defect and was found to be normal.
The native aorta appeared healthy. Eleven interrupted pledgeted 4-0 Tycron sutures were taken around the defect, leaving the pledgets inside the aorta. The defect was closed using a 3 x 3 cm polytetrafluoroethylene patch (Fig 4).
A root vent was placed to remove air from the system. After repairing the defect, the root was placed on suction, and cardiopulmonary bypass recommenced. Hypothermic circulatory arrest lasted for 35 minutes. The patient was rewarmed, and the heart picked up spontaneously in sinus rhythm. He was weaned off bypass once normothermia was reached.
The chest was closed after inserting mediastinal and bilateral pleural drains.
The patient remained hemodynamically stable on minimal inotropic support and was extubated the next morning with no obvious neurologic sequelae.
The cause of the pseudoaneurysm appeared to be a blowout at the previous aortotomy site, because there was no evidence of infection intraoperatively, and cultures taken from adjacent tissues and intraluminal blood clots remained sterile.
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Comment
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Pseudoaneurysms of the ascending aorta after aortic valve replacement usually occur at anastomotic suture lines or at aortotomy, aortic cannulation, or aortic needle puncture sites. Patients with chronic hypertension and aortic calcification are at higher risk. Most episodes have infective causes, but in a few patients, no infection can be demonstrated [1, 4].
Contrast CT scanning, magnetic resonance imaging, and echocardiography are useful in the diagnosis of pseudoaneurysms of the ascending aorta, with high sensitivity and specificity [1]. Surgical repair is mandatory.
The central issue here is achieving profound hypothermic circulatory arrest before opening the chest. In patients with aortic insufficiency, hypothermia causes ventricular fibrillation and distension, resulting in myocardial damage [5]. In our case, because the prosthetic aortic valve was competent, the above complication was less likely.
This technique allowed for minimal blood loss and an uneventful recovery.
Inadvertent pseudoaneurysm rupture during a repeat sternotomy or mediastinal dissection can lead to a catastrophic intraoperative hemorrhage and exsanguination [6].
The use of femorofemoral bypass and hypothermic circulatory arrest before sternotomy helped us prevent an impending rupture. Achieving profound hypothermia also gave adequate time to safely repair the defect with a patch.
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References
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Abstract
Introduction
