Use of Multiple Stents to Seal Off an Epicardial Pseudoaneurysm

Pseudoaneurysms of saphenous vein grafts are rare following coronary artery bypass surgery. They occur most often at the proximal anastomosis secondary to vessel layer disruption. Rarely do they occur distally. We report the case of a pseudoaneurysm involving the saphenous vein graft to a circumflex marginal branch at the distal anastomosis site. Case Report. A 69-year-old male presented initially with shortness of breath and chest pain; an exercise stress echocardiogram was positive for inducible ischemia, and subsequent cardiac catheterization revealed triple-vessel disease. The patient underwent coronary artery bypass surgery. His hospital course was complicated by a large left pleural effusion, and a diagnosis of post-cardiotomy syndrome was made that responded to thoracentesis and steroid therapy. Prior to commencing cardiac rehabilitation, an echocardiogram 3 months following surgery revealed a 6.0 cm mass compressing the posterior wall of the left ventricle. A computed tomography (CT) scan of the chest with contrast showed a 6.0 x 6.0 cm mass with enhancement, and therefore a left heart catheterization was undertaken. This revealed the bypass grafts all to be patent. However, the saphenous vein graft to the circumflex marginal branch at the distal anastomosis revealed a leak contained in the pericardial sac with the formation of a pseudoaneurysm, compressing the left ventricular cavity. A covered stent was not immediately available, so we harvested a piece of the saphenous vein and mounted it on a 3 mm AVE stent. We were unable to successfully deploy the stent to the distal segment, most likely secondary to the compression of the distal vein graft by the pseudoaneurysm. A 3.0 x 13 mm Tristar stent was deployed across the neck of the aneurysm, but the jet of contrast still persisted. A second 3.0 x 16 mm NIR stent was deployed within the first stent. After placement of 2 stents, there was significant reduction in the leak; we then inserted a third 3.0 x 8.0 mm Tristar stent within the first 2 stents followed by a prolonged balloon inflation. This was successful in occluding the pseudoaneurysm and preserving the flow into the circumflex marginal branch. We think the most likely mechanism was that 3 stents deployed concentrically diminished the flow of blood across the neck of the aneurysm, and then a prolonged inflation allowed complete thrombosis within the aneurysm. At 6-week follow-up, repeat CT scan revealed the size of the mass to be smaller with no contrast enhancement (which is indicative of flow) of the mass. We performed a stress echocardiogram. The patient walked 8 minutes on standard Bruce Protocol, achieving 85% of his target heart rate without any electrocardiographic or wall motion abnormalities to suggest ischemia. Discussion. Pseudoaneurysms of vein grafts have been reported early after surgery, but the majority of them were detected late after surgery, as late as seventeen years.^1–12 Presentations can include postoperative mediastinitis, fistulas with erosion of the vein grafts to the right atrium or anterior chest wall.^8,12–14,16 They may be caused by tension on the graft anastomosis. In addition, infection can develop at the site of suture lines, causing these pseudoaneurysms.^7,12–14 Myocardial infarction secondary to embolization has also been described.15 The dreaded complication of these pseudoaneurysms is obviously rupture, with the potential for death.^1,2,11 The treatment has varied as the field of interventional cardiology has progressed. The majority of cases are still treated with surgical resection with or without redo bypass surgery.^1,3,11,12 Rare cases have been described using autologous vein grafts mounted on stents.^17,18 Coil embolization of the pseudoaneurysms has also been described.^4,19 The case described is the first reported case of pseudoaneurysm closure using multiple stents while preserving distal run-off in the vein graft. Because the occurrence is rare, the experience is quite limited. The covered stents will simplify distal anastomotic pseudoaneurysm management, provided the stent is deliverable to the site. Our approach can be considered as an alternative when bulky covered stents are not deliverable to a distal pseudoaneurysm.

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