A 55-yr-old male presented with acute chest pain, dyspnea, and hypotension on December 8, 2009. The patient has been followed without any medications for incidentally detected asymptomatic SVC aneurysm for last 2 yr (, and the size of the SVC aneurysm did not change (). Chest radiography at admission showed marked widening of the right middle mediastinum due to abnormal soft-tissue density suggesting the rapid expansion of previously noted SVC aneurysm (). Echocardiography revealed marked enlargement and hypokinesia of the right ventricle (RV) with moderate pulmonary hypertension suggesting acute PE. Chest computed tomographic angiography (CTA) showed about 6.9 × 6.1 × 9.9 cm sized lobulated giant saccular aneurysm originating from mainly SVC and partially involving left brachiocephalic vein with internal thrombi (). Considerable amounts of thromboembolic filling defects in left pulmonary artery, both left and right lobar, segmental, and subsegmental arteries were also noted (). Three-dimensional reconstruction with endovascular views showed the giant saccular SVC aneurysm with 4.1 × 3.7 cm sized internal thrombi, and the thrombi protruded into the SVC through the narrow aneurysmal neck (). Venous CTA of the lower extremities and abdominal CTA showed no evidence of deep vein thrombosis or other venous aneurysms. To exclude the possible hypercoagulable status as a cause of pulmonary thromboembolism, the laboratory tests for hypercoagulability was done and revealed no abnormalities. Surgical exclusion of SVC aneurysm with pulmonary embolectomy was planned, but the patient and family refused surgery. Therefore, thrombolytic therapy using recombinant tissue plasminogen activator with the dose of 200 mg was administered intravenously for 2 hr for hemodynamically significant PTE, and the RV function and pulmonary artery pressure was normalized on FU echocardiography. However, the patient complained recurrent chest pain and dyspnea on the next day. FU CTA revealed more decreased amounts of thrombi in the left pulmonary artery and its branches, but the amounts of thrombi in the SVC aneurysm, SVC, right pulmonary artery and its branches were increased. Mobilization of thrombi from the SVC aneurysm due to thrombolytic therapy was the possible cause of recurrent PTE, and it was expected that further embolization of thrombi would be fatal to the patient. Therefore, surgical treatment was strongly recommended. Resection of SVC aneurysm and pulmonary artery embolectomy were performed successfully. At surgery, femoral arterial and venous cannulation was done to prepare for accidental rupture of aneurysm during sternotomy. After dissection of the aneurysm, the other venous cannulation at the innominate vein and isolation of the proximal and distal portion of the aneurysm was done. Under cardiopulmonary bypass, aneurysmal wall was opened longitudinally after snaring of proximal and distal portion of the aneurysm and innominate vein. Aenurysm which contained fresh thrombi was thin-walled and had relatively normal venous endothelium grossly (), and the histopathologic examination showed compatible findings of true aneurysm (). Thin-walled aneurysmal wall was completely resected and subsequent reconstruction of the superior vena cava was performed with glutaraldehyde fixed autologuous pericardium that was already harvested. Outer surface of the pericardium was buttressed with Dacron to prevent potential formation of pseudoaneurysm. A transverse arteriotomy was made in the pulmonary trunk to the left main pulmonary artery and another incision was made in the right main pulmonary artery, and the fresh and organized thrombi were gently extracted. Following the successful surgical management, the mediastinal widening on chest radiography was normalized () and the patient was recovered without any postoperative events. The patient was discharged and treated by anticoagulation with warfarin for 6 months to achieve complete resolution of the possible remained pulmonary arterial thrombi.
A 73-year-old female presented as an outpatient from her primary care physician for a CT of the thorax, abdomen, and pelvis to evaluate a reportedly stable abdominal aortic aneurysm. Pertinent past medical history revealed a left supraclinoid internal carotid artery aneurysm, a stable infrarenal abdominal aortic aneurysm, systemic lupus erythematous/rheumatoid arthritis overlap syndrome, smoldering IgG lambda myeloma, chronic kidney disease (stage II), hyperparathyroidism, and a cerebral infarction in the right posterior cerebral artery territory in 2009. Findings on the CT of the thorax demonstrated a fusiform superior vena cava (SVC) aneurysm measuring 5.9 × 4.4 × 6.1 cm (anterior-posterior × transverse × craniocaudal). No thrombus was noted within the SVC aneurysm (). The aneurysm was first partially visualized in 2007 on a cervical spine CT, and since that time it had remained stable on annual follow-up CTs.\nThe patient's course between 2007 and the most recent study in 2016 included an extensive rheumatologic and hematologic workup, including a temporal artery biopsy in 2015. Pathology revealed intimal hyperplasia with focal internal membrane disruption, but no features of granulomatous vasculitis were identified.\nThe etiology of the SVC aneurysm in this patient is uncertain. Potential causes in this patient include autoimmune disease (RA/SLE), which seems unlikely. Pathology did not reveal any convincing evidence of vasculitis. The arterial aneurysms are also felt to be unrelated as the patient has significant atherosclerotic disease. While an iatrogenic cause is possible, a chart review did not elicit any complications relating to prior hemodialysis catheter placement. Therefore, we surmised that the SVC aneurysm was likely idiopathic.\nThis patient did not receive any anticoagulation to prevent thrombus formation within the SVC aneurysm, and no repair was ever attempted. For the six years during which the patient was under observation at our institution, an SVC thrombus or sequela of an embolus originating from the SVC has never been observed. While the patient had a cerebral infarct in 2009, there was no evidence of right to left circulatory shunt. The observatory management of the SVC aneurysm in this patient stands in contrast with the majority of the cases found in the literature. Most patients were treated prophylactically for theoretical complication.