Archived case 207 · July 18-July 25, 2016

Pseudoaneurysm of the saphenous vein graft

Continued from last Case -72 year old male with chest discomfort

The question posed to readers

Abnormal chest radiograph prompted further workup with coronary CT angiogram.

Imaging findings

Comparing the chest radiographs of 2011 and 2015: A dual-chamber pacemaker has been placed in the interim. There are median sternotomy wires and evidence of prior coronary artery revascularization. There is interval enlargement of the heart size with worsening vascular congestion. A round structure has developed alongside the left atrial appendage, which may represent an aneurysm or a mediastinal mass. The coronary CT angiogram demonstrates: The patient is status post three vessel coronary artery bypass graft. There is cardiomegaly with enlargement of all four chambers. There is a pseudoaneurysm, arising from saphenous vein graft, near its distal anastomosis. There is active extravasation into the pseudoaneurysm. There is differential contrast enhancement and partial thrombosis of the posteromedial aspect of the pseudoaneurysm. There is mass effect on the left atrium and left atrial appendage. Hypoperfusion of the coronary artery territory supplied by this graft is noted. The left internal mammary artery (LIMA) to left anterior descending artery (LAD) graft is patent. The right coronary artery (RCA) graft is patent with normal flow distally. Answer Diagnosis: Pseudoaneurysm of the saphenous vein graft

Diagnosis

Pseudoaneurysm of the saphenous vein graft

Aneurysm of the saphenous vein graft (SVG) is a rare but fatal complication of coronary artery bypass surgery. The true incidence of this is underestimated, as the initial presentation could be rupture of the aneurysm leading to cardiac tamponade and sudden death. Pseudoaneurysm usually occur at the anastomotic site, which are thought to be a result suture rupture or erroneous suture placement, or infection. Aneurysm and pseudoaneurysm of saphenous vein grafts are initially encountered on routine chest radiograph, either as a mediastinal or a hilar mass. Further evaluation can be obtained with echocardiography, Computed Tomography of the chest with intravenous contrast, Magnetic Resonance Imaging and Magnetic Resonance Angiography. Coronary angiography is strongly recommended even after the diagnosis is established with one of the noninvasive techniques. Intravascular ultrasound (IVUS) in conjunction with coronary angiography which can differentiate between true and false aneurysms. The most common complications seen are myocardial infarction, sudden rupture leading to hemothorax and hemopericardium, and sudden death. The recommended treatment is surgical excision and revascularization. Coil embolization and covered stents have been proposed as nonsurgical management. References Saphenous Vein Graft Aneurysm: Case Report and Review. Memon AQ, Huang RI, Marcus F, Xavier L, Alpert J., Cardiol Rev. 2003 Jan-Feb;11(1):26-34

Original case written by its authors at Virginia Commonwealth University and published at this address as part of a weekly teaching collection. Reproduced here as an archive.

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Pseudoaneurysm of the saphenous vein graft

The question posed to readers

Images

Imaging findings

Diagnosis