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Case presentation

A 39-year-old woman with a past medical history significant for Marfan syndrome presented to our hospital for evaluation of chest pain and worsening dyspnea upon exertion. Her history was significant for aortic root replacement with an aortic composite graft and mitral valve replacement surgery in 1997 due to ascending aortic aneurysm, aortic insufficiency, and mitral regurgitation. During the operation, she did have bleeding at the left coronary button which was successfully repaired. During the postoperative period, she developed myocardial ischemia. Transesophageal echocardiography (TEE) revealed inferior and lateral wall hypokinesis. She was taken back to surgery, and a Y-shaped saphenous vein graft was placed with a single take off from the ascending aorta. The distal ends of the graft were anastomosed to the left anterior ascending artery (LAD) and right coronary artery (RCA). After the second operation, her postoperative course was complicated by cardiac tamponade which was subsequently drained. The patient again required repair of the left coronary button. The patient subsequently did well and was asymptomatic for a long period of time. She had been followed up by the cardiologist and cardiothoracic surgeon with clinical examination and computed tomography angiography (CTA). Her first cardiac computed tomography was performed in 2001 which showed postsurgical change of aortic root without aneurysm.

In 2004, 5 years prior to her current admission, abnormal aneurysmal dilatation of the ascending aorta was noted on routine CTA. Treatment options including surgery vs. observation were discussed with the patient. The patient opted for conservative management primarily because she was asymptomatic. For the past 2 years, she had multiple episodes of chest pain and shortness of breath. The surgical option was discussed again, but the patient insisted on nonsurgical management. Recently, her symptoms worsened and required hospitalization for chest pain and dyspnea. Coronary CTA demonstrated a pseudoaneurysm of the ascending aorta, approximately1.5×1.5 cm in maximum diameter, originating from the implantation site of the saphenous vein graft ( Fig. 1 A –C). Coronary angiography with ascending aortography demonstrated an irregular contour pseudoaneurysm originating from the vein graft anastomosis of the ascending aorta which was compressed against the distal vein graft ( Fig. 2 A and B). The left and right coronary buttons and origin of LAD vein graft limb were found to have critical stenosis.

(A) Contrast-enhanced coronary CTA demonstrates an anterior pseudoaneurysm of the ascending aorta (white arrow) communicating with saphenous vein graft. (B) Sagittal reconstruction of contrast-enhanced coronary CTA demonstrates the pseudoaneurysm of the ascending aorta (white arrow) extending inferiorly. (C) Three-dimensional reconstruction of coronary CTA demonstrates the anterior pseudoaneurysm (white arrow) communicating with saphenous vein graft to RCA and LAD.

(A) Ascending aortography demonstrates an AAP (white arrow) originating from the vein graft anastomotic site. (B) Ascending aortography demonstrates the communication of ascending aneurysm with saphenous vein graft to LAD and RCA.

Based on symptoms and findings, the patient agreed to repair of the pseudoaneurysm and coronary artery bypass graft revision. Cardiopulmonary bypass was established with arterial cannulation at the proximal arch opposite to the left common carotid artery and a long 25-F venous catheter from the left femoral vein to the right atrium for venous cannulation. The pseudoaneurysm was found arising from the anastomotic vein graft site, compatible with findings from CTA and angiography. Her vein graft to the RCA was ligated and a new saphenous vein graft was implanted. A second vein graft was also placed from the aorta to the obtuse marginal branch of the left circumflex artery. Her previous vein graft to the LAD was found to originate from the pseudoaneurysm, but the entire graft was soft and free from obvious atheromatous plaque. This vein graft was excised and reanastomosed to the side of obtuse marginal branch vein graft. The pseudoaneurysm was dissected and repaired with Hemashield patch. This patient’s postoperative course was uneventful and she was able to be discharged by the sixth day after surgery.

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Discussion

Ascending aortic pseudoaneurysm is a rare complication which occurs in less than 0.5% of all cardiothoracic surgical cases . Pseudoaneurysm can originate from previous anastomotic sites, aortotomy suture line, cannulation sites, venting sites, and proximal vein graft anastomotic sites . Possible mechanisms include infection, technical issues, and intrinsic disease of the aortic wall . Among those possible etiologies, infection was reported to be the most prominent cause in up to 50% of cases. Staphylococcus aureus seems to be the most prevalent organisms in blood culture-positive patients . Inherited connective tissue disorders, such as Ehler Danlos and Marfan syndrome, were estimated at 3.3–10% of pseudoaneurysm cases .

Marfan syndrome is an autosomal dominant connective tissue disorder, caused by mutations in the fibrillin-1 gene on chromosome 15, resulting in abnormal microfibrils and weakening of the extracellular matrix in connective tissue. This defect results in aneurysmal dilatation of the aortic annulus, aortic root, and the aorta itself, as well as abnormalities of the aortic valve, mitral valve, len, tendons, and bones. Typically, an ascending aortic aneurysm in Marfan syndrome requires repair when it reaches 5 cm in diameter . Operation can be considered sooner in higher risk situations such as rapid progressive dilatation, family history of Marfan syndrome and aortic dissection, and women planning pregnancy. The aneurysmal segment is generally resected and replaced with composite graft, as in our patient. The incidence of AAP is unclear. One report by Kouchoukos et al. found the incidence to be about 10% of Marfan syndrome patients who underwent aortic root replacement.

Approximately half of the AAP cases present within 2 years after surgery, but intervals up to 18 years have been reported . Patients can present with chest pain, dyspnea, fever, and mass-effect symptoms (e.g., dysphagia, stridor, hoarseness, hemoptysis, or pulsatile suprasternal mass) . Occasionally, a pseudoaneurysm can be found incidentally on imaging in asymptomatic patients. Our patient was 7 years from her original surgery at the time of asymptomatic detection. She remained symptom free until the past 2 years. Surgical treatment must be discussed with all patients regardless of symptoms, as the risk of rupture could be catastrophic .

In the past, aortography was the most useful modality for diagnosis . CTA and magnetic resonance angiography (MRA) are presently the primary diagnostic tools. Transesophageal echocardiography is helpful, but false-negative results have been reported with TEE . These imaging modalities allow one to define the extent of the lesion and also the relationship between the pseudoaneurysm and sternum. This provides surgeons with anatomic information to plan surgical approach. The routine use of imaging modalities to screen for AAP is usually not done, but most patients with aortic connective disease or aneurysm prior to surgery usually undergo periodic follow-up with CTA or MRA.

The surgical management of AAP remains a challenge. Even an asymptomatic pseudoaneurysm should be advised to undergo repair due to a chance of late rupture . During sternal reentry or surgical repair, the reported inpatient mortality rate ranged from 6.7% to 60%. This is mostly due to rupture of the pseudoaneurysm. . Careful median sternotomy or hypothermic circulatory arrest using femoral–femoral bypass is a helpful strategy. Using bilateral carotid artery cannulation and femoral cannulation allows mediastinal dissection and control of the distal aorta without compromising of cerebral perfusion even in cases of massive hemorrhage from a ruptured pseudoaneurysm intraoperatively . Repair of the AAP depends on etiology. When an infection is present, infected tissue and prosthesis should be removed and replaced with an aortic homograft. In smaller, noninfected pseudoaneurysms, direct suture closure or patch closure may be sufficient. In our patient, the pseudoaneurysm was successfully repaired without using carotid or femoral artery cannulation. This was performed as the distance between the pseudoaneurysm and sterum was enough so that sternotomy could be performed without rupture. Also, the proximal aortic arch was not involved with the pseudoaneurysm, which allowed cannulation of the aorta rather than using the femoral artery.

In conclusion, we described a case of AAP, which was diagnosed 7 years following initial operation and repaired 12 years following initial operation, in a patient with Marfan syndrome. Chest CTA, coronary angiography, chest MRA, and TEE are very helpful in diagnosis of pseudoaneurysm and surgical planning. Standard strenotomy and bypass are appropriate for most patients in whom CTA or MRA shows the AAP to be away from the sternum. If the AAP is close to or invades the sternum, then deep hypothermia and circulatory arrest with femoral cannulation may be necessary. Other options include subclavian and carotid cannulation to maintain antegrade cerebral blood flow. Finally, because of the high risk of rupture, surgical repair is indicated before catastrophic complications develop.