One rare complication associated with the GSV is an aneurysmic extension of the vein graft. In the present case report, we describe an aneurysm in a female patient 20 years after her femoropopliteal bypass operation using the GSV.
The patient had a significant history of coronary artery disease. In 1998, she developed a myocardial infarction of the posterior wall and underwent percutaneous coronary angioplasty. Repeated percutaneous interventions were needed as the coronary stents re-occluded. The operation described in this case report was further complicated by the adverse risk factors presented with arterial hypertension and hyperlipoproteinemia. We preceded to remove the vein graft of the femoropopliteal bypass and then implanted an 8 mm polytetrafluoroethylene (PTFE) synthetic graft as the femoropopliteal bypass graft (Figure 2a, b).
Figure 2: (a, b) Partially saccular aneurysm of the vein graft of the femoropopliteal bypass.
Methods
Histological investigations
Under sterile conditions, segments of the bypass
graft were harvested and fixed in a buffered 3.7%
formaldehyde solution at 4 °C for at least 24 hours.
Specimens were dehydrated in an ascending series of alcohol and embedded in paraplast using an automatic
embedding machine (Histokinette 2000, Reichert-Jung
London, UK). Five μm thick serial sections were cut
using a Jung-Biocut microtome (Reichert-Jung Biocut;
Leica, UK) veya (Leica Biosystems, Wetzlar, Germany)
and mounted on glass slides coated with albuminglycerine.
Samples were then deparaffinized and finally
stained by conventional techniques [hematoxylin-eosin
(HE), Goldner, and van Gieson].
Scanning electron microscopy
To investigate the influence of fixation and anticalcification
methods on the ultrastructure of the vein
graft, scanning electron microscopy (SEM) was used.
Samples were fixed in 2.5% glutaraldehyde solution,
buffered in 0.2 M cacodylate, dehydrated in an ascending
series of alcohol (70-80%), and dried in a critical
point drier (Polaron). The samples were then sputtered
with gold-palladium in a COOL-sputterer (Polaron).
The electron microscopic examination was carried out
with a digital scanning microscope (DSM 960, Zeiss,
Germany).
Histological results
Histologically, the venous segment had evidence of
arterial-like changes. The adventitia and endothelium
were clearly thickened. The tunica media had become
detached from the hyaline plate, symptomatic of hyaline
degeneration. Therefore, this indicates an extension of
the veins in the form of an aneurysm (Figure 3).
Electron microscopical results
In the SEM, an enormous thickening of the adventitia
and tunica media was generally noted which was mainly
caused by collagen hyperplasia. However, hyperplasia
of the endothelium was less noticeable. In some parts,
luminal stenosis due to the hyaline mass was observed
which corresponds to demineralised cartilage. In
addition, the venous wall had degenerative changes most
prominent in the region of the aneurysm (Figure 4).
The use of the GSV as a bypass conduit for lower extremity revascularization provides improved longterm outcomes compared with the use of synthetic grafts.[3-6] This is especially important in below-knee, lower extremity revascularizations. Greater saphenous vein grafts have been noted to have the rare complication of developing an aneurysm.[7,8] We have described a case with a GSV aneurysm which developed 20 years after the femoropopliteal bypass operation.
The progression of peripheral arterial disease is believed to result from the implanted vein grafts. We have described an alternate mechanism for the development of stenosis in the implanted venous bypass grafts.[9] The development of aneurysms in the internal carotid artery and the suprainguinal bypass as well as the infrainguinal bypass has been described. We found hyaline degeneration of the tunica media with hyperplasia of the collagenous fibers, likely an adaptation process. A clear stenosis of the lumen was present given that the hyaline mass penetrated the lumen in spite of the aneurysm. This makes operative intervention a necessity given the high risk of peripheral thrombosis or embolization. Although we have presented one case, further examination of explanted venous bypass grafts is needed to provide additional details on the etiology of bypass graft aneurysm.
Declaration of conflicting interests
The authors declared no conflicts of interest with respect
to the authorship and/or publication of this article.
Funding
The authors received no financial support for the
research and/or authorship of this article.