Medical Care
Because saphenous vein graft aneurysms (SVGAs) are rare, the approach to management has been derived from case reports and case series. Dieter and colleagues reported the outcome of 13 patients, two of whom had surgical therapy, while the remainder were deemed poor surgical candidates due to comorbid conditions. [9] Eight patients had an uneventful follow-up course while being managed medically, and there was no survival benefit attributed to either surgical or conservative management.
No “safe” size for SVGA surveillance is known, as even "small" SVGAs measuring up to 20 mm treated conservatively were associated with adverse outcomes in one third of cases. [3] Mortality for patients receiving conservative management was higher at 23.8% than in similar patients managed with surgery (13.9%) or percutaneous intervention (6.1%). [3] Regardless, patients may be treated conservatively because of comorbid conditions precluding surgery or because of patient preference.
Medical therapy has also been pursued based on imaging characteristics suggesting low risk for rupture, such as a thick aneurysm wall or absence of flow into the aneurysm because of thrombus, especially in asymptomatic patients. Additional features that may support conservative management include aneurysm diameter less than 1 cm and brisk flow through the graft. This strategy should include surveillance imaging with magnetic resonance imaging (MRI), computed tomography (CT) scanning, or coronary angiography to monitor aneurysm growth over time.
Of note, antihypertensive and cholesterol-lowering therapy, such as with a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor (statin), may be beneficial in slowing aneurysm progression but limited data are available. The benefit of anticoagulant therapy with warfarin (Coumadin) is not known. The role of beta-blockers in preventing further SVGA dilatation, in contrast to their role in treating aortic aneurysms, has not been well studied. However, many of these patients, particularly those with angina, left ventricular systolic dysfunction, and/or a history of myocardial infarction, benefit from beta-blocker therapy. Aspirin is generally recommended in most patients with SVGA based on the presence of underlying coronary artery disease.
Diet and activity
A heart-healthy diet should be followed to reduce risk factors for further cardiac disease; however, the influence of diet on subsequent aneurysm formation is unknown. Early mobilization followed by gradual resumption of normal activity is important for successful postoperative recovery.
Consultations
Careful monitoring in the intensive care unit is required during the initial postoperative period if surgical resection or percutaneous intervention is performed. The Heart Team approach involving cardiologists and cardiothoracic surgeons is recommended for thorough patient evaluation.
Surgical Care
Sareyyupoglu et al retrospectively reviewed data from 16 patients who underwent surgical saphenous vein graft aneurysm (SVGA) repair. The authors recommended surgical revascularization for symptomatic patients, patients with aneurysms exceeding 1 cm in diameter, or patients with evidence of diminished graft flow. [2] Memon et al supported coil embolization as an alternative treatment option in patients with high surgical risk. [26]
A review of the literature suggests management ranges from surgical (58.4%) to percutaneous intervention (15.8%) to conservative management (20.1%). [3] Surgical therapy is generally considered when an SVGA is discovered, given the morbidity and mortality associated with aneurysm rupture. The optimal timing of surgery is unknown; however, in cases of symptomatic aneurysms, suspected mycotic aneurysm, fistula formation, and/or confirmed false aneurysm, urgent surgical intervention is strongly recommended. The traditional surgical approach has been ligation of the aneurysm-containing saphenous vein graft (SVG) and placement of a new bypass graft. [3]
Percutaneous options now include Amplatzer devices, covered stents, and coiling. [27, 28] Historically, percutaneous therapy has been reserved for patients who are poor surgical candidates. However, as percutaneous techniques evolve, these approaches are being considered as alternatives to surgical intervention. One such technique that has been described uses coil embolization of the aneurysm (see the videos below). However, this technique carries the risk of occluding flow to the bypassed arterial system. More recently, "stent-assisted" coil embolization has been described, whereby a stent is placed in the parent vessel across the mouth of the aneurysm, providing a scaffold to prevent prolapse of the coils into the parent vessel once deployed in the aneurysm. Rezq et al reported success with peripheral covered stents as an alternative to surgery. [27]
Covered stents have been used to isolate the aneurysm from the graft lumen; the JOSTENT Coronary Stent Graft, consisting of an ultra-thin layer of polytetrafluoroethylene (PTFE) sandwiched between two stainless steel stents, has been used successfully in several cases. [29] However, the results have been mixed due to technical issues. In one case, the JOSTENT migrated into the aneurysm, requiring placement of a second overlapping bare metal stent for repositioning, finally achieving a good result. [29] In a second case, the JOSTENT achieved an excellent immediate angiographic result with exclusion of a false aneurysm, but on routine 6-month angiography, the false aneurysm recurred in the same location, possibly due to focal perforation of the PTFE layer. [29]
Placement of autologous vein graft-covered stents has been used successfully, and in one patient in which a covered stent was not immediately available, three overlapping uncovered stents with prolonged balloon inflation successfully excluded a false aneurysm. [30]
In choosing between uncovered bare metal stents and drug-eluting stents, drug-eluting stents in SVGs yield superior long-term outcomes. For patients undergoing percutaneous coronary intervention (PCI) in SVGs, drug-eluting stents may be preferred to bare metal stents because they have a lower risk of target vessel revascularization. For example, Brilakis et al compared restenosis rates after the placement of paclitaxel-eluting stent versus bare metal stent in SVG lesions. [30] They found that paclitaxel-eluting stents were associated with lower rates of target vessel failure and angiographic restenosis than bare metal stents. [30] No differences are recognized between drug-eluting stents and bare metal stents in terms of stent thrombosis when used in SVG interventions. [31]
A newer approach that has been used is placement of the Amplatzer vascular plug; in a single reported case, an 8-mm device was placed in the neck of a 9-cm true SVGA with an excellent result. [32] Although reports suggest that surgery remains the preferred treatment strategy for SVGAs, morbidity and mortality are higher when compared with percutaneous approaches such as covered stents. [10, 13]
Endovascular stent graft repair of an SVGA by adapting an abdominal aortic graft to the ascending aorta has also been suggested in the setting of patients not candidates for traditional open repair for ascending aneurysms or dissections. [33]
Long-Term Monitoring
Instruct patients to immediately return to the hospital if symptoms recur.
Patients who have been medically treated require close follow-up care to detect progression of saphenous vein graft aneurysm (SVGA) disease and emergence of other graft aneurysms.
Most importantly, patients need continued medical treatment of coronary artery disease and atherosclerosis.
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Saphenous Vein Graft Aneurysms. Computed tomography scan demonstrating a saphenous vein graft aneurysm.
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Saphenous Vein Graft Aneurysms. Cardiac catheterization demonstrating a saphenous vein graft aneurysm.
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Saphenous Vein Graft Aneurysms. Aortogram demonstrating a saphenous vein graft aneurysm.
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Saphenous Vein Graft Aneurysms. This computed tomography scan reveals a saphenous vein graft aneurysm.
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Saphenous Vein Graft Aneurysms. Angiogram of a saphenous vein graft to the distal right coronary artery demonstrating a large aneurysm in the mid portion of the graft. Video courtesy of John S. Douglas, MD.
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Saphenous Vein Graft Aneurysms. Final angiogram demonstrating coils within the aneurysm, and almost complete cessation of flow from the parent vessel into the aneurysm. Video courtesy of John S. Douglas, MD.
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Saphenous Vein Graft Aneurysms. Another view demonstrating the saphenous vein graft aneurysm. Video courtesy of John S. Douglas, MD.
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Saphenous Vein Graft Aneurysms. The first of many coils being deployed in the aneurysm. Video courtesy of John S. Douglas, MD.
