Atheromatous lesions in arterialized vein grafts. An experimental study

Atherosclerotic aneurysm formation in a lower extremity saphenous vein graft

Saphenous vein is the most widely used conduit for arterial bypass procedures and aneurysms of the vein graft are rare. We report a true aneurysm of a reversed femoropopliteal saphenous vein graft implanted nine years earlier. Duplex ultrasonography identified an aneurysm of the saphenous vein graft and arteriography confirmed this finding. A consideration for endovascular coiling of the aneurysm was entertained, but no proximal "neck" on the aneurysm was present. The patient, therefore, underwent an uneventful resection of the aneurysm with end-to-end anastomosis. Histopathologic examination of the aneurysm demonstrated atherosclerotic degeneration with endothelial disruption, medial necrosis, and fibrous proliferation. The cause of a saphenous vein graft aneurysm is rare and unknown. The management of vein graft aneurysms, however, should be subject to the same criteria that apply to other aneurysms because once vein graft dilation occurs, it is followed by a rapid increase in size, which may lead to possible rupture.

[True aneurysms of venous autografts: report of nine cases and review of the literature]

INTRODUCTION The true aneurysm formation of the autogenous saphenous vein graft (ASVG) is a very rare complication after bypass surgery [1 -5]. In 1969 Pillet [1] first described a true fusiform aneurysm formation of the ASVG which had been used as a replacement of the iwured superficial femoral artery in 26-year-old male patient. We present nine cases. CASE!. A 71-year-old man with previous history of arterial hypertension and higher serum lipid level, was admitted with an asymptomatic pulsating swelling of the medial portion on the thigh. Five years ago the bellow knee F-P bypass with ASVG due to occlusive disease has been performed. The transfemoral angiography (Figure 1) showed patent graft with fusiform true aneurysm formation at its mid portion. This aneurysm has been replaced with PTFE graft. The pathohistological examination showed an atherosclerotic origin of the aneurysm. This patient died four years after operation due to myocardial infarction with patent graft. CASE 2. A 57-year-old female with previous history of arterial hypertension and higher serum lipid level, had an elective resection and replacement of the superficial femoral artery aneurysm. For the reconstruction an ASVG was used. The saphenous vein showed postflebitic changes. Four years later she was admitted with asymptomatic pulsating mass of the mid portion of the thigh. The control transfemoral angiography showed patent graft with fusiform aneurysm formation of its mid portion. After aneurismal resection, an above knee F-P bypass with 8 mm PTFE graft was performed. A pathohistological examination showed a partially degenerated elastic membrane with fragmentation and disruption, without atherosclerosis (Figure 2). During the follow up period an elective resection of the subclavian artery aneurysm as well as abdominal aortic aneurysm, were performed. CASE3. A subclavian artery aneurysm caused by TOS has been repaired with sapehnous vein graft at 40-year-old female patient with regular arterial tension and normal serum lipid level. The pathohistologycal examination showed an intimai fibroelastosis associated with intimai and medial connective tissue proliferation of the aneurysm. The atherosclerotic changes were absent. Four years later this patient has been admitted urgently with ischemia of the left hand, absent distala arterial pulses and with asymptomatic pulsating mass over the supradavicular area. The Duplex ultrasonography and angiography, showed aneurysm of the ASVG, associated with occlusion (embolism) of the brachial artery (Figure 3). This aneurysm has been replaced with 6 mm PTFE graft Transbrachial thrombembolectomy has been performed too. The pathohistological examination showed a non atherosclerotic origin of the ASVG aneurysm (Figure 4). Three years after secondary operation the PTFE graft is patent. Echocardiography of the same patient showed mitral valve prolaps, probably caused by connective tissue disorder. CASE 4. A 56-year-old female patient was admitted urgently, due to hemorrhagic shock and giant pulsating swelling over the popliteal space. The Duplex ultrasonography and transfemoral angiography showed ruptured popliteal artery aneurysm. This patient had arterial hypertension and higher lipid level. During the urgent operation using dorsal approach, an aneurysm has been replaced with ASVG. A pathohistological examination showed an atherosclerotic origin of the aneurysm. Ten days postoperatively due to bleeding from the wound, a new urgent surgical procedure was performed. Intraoperatively 1 cm long graft laceration was found, while postoperative bacteriological examination showed an infection caused by Staphylococcus Aureus. The graft has been removed, and new extraanatomic, subcutaneous bypass from the superficial femoral to anterior tibial artery using ASVG was performed. Three years later this patient was admitted urgently with giant pulsating mass and skin necrosis at the knee region, associated with hemorrhagic shock. The control angiography showed a ruptured aneurysm of the ASVG (Figures 5 and 6). The aneurysm was replaced with 6mm PTFE graft. The pathohistological examination showed an atherosclerotic origin of the aneurysm. Two year postoperatively, the new graft is patent. CASE 5. A 65-year-old man with previous history of arterial hypertension and high serum lipid level, was admitted with pulsating swelling and skin necrosis at the portion on the thigh. Nine years ago the bellow knee F-P bypass with cephalic vein due to occlusive disease has been performed. Transfemoral angiography showed patent graft associated with ruptured fusiform aneurysm at its mid portion. This aneurysm has been replaced with 6mm tubular PTFE graft. The postoperative patohistological examination showed an atherosclerotic changes at the resected aneurysm. This patient was followed two years, and graft is patent., CASE 6. A 62-year-old male patient was admitted urgently, with giant pulsating swelling over the popliteal space and hemorrhagic shock. The Duplex ultrasonography and angiography showed ruptured popliteal artery aneurysm. The patients had previous history of arterial hypertension and higher serum lipid level. The aneurysm has been replaced with ASVG. Pathohistological examination showed an atherosclerotic origin of the aneurysmal sac. Seven days postoperatively, a massive bleeding from the wound due to graft infection, occurred. New urgent operation showed complete graft abrupption at the site of proximal anastomosis, while postoperative bacteriological examination showed a presence of Staphylococcus Aureus. The graft was removed and new extraantomic, subcutaneous bypass from the superficial femoral to the anterior tibial artery with contralateral ASVG, was performed. The patient recovered very well. Five years latter this patient was admitted urgently with large painful pulsating mass in the thigh. The angiography showed and ASVG fusiform aneurysm. The aneurysm has been replaced with 6 mm PTFE graft. The pathohistological examination showed an atherosclerotic origin of the resected aneurysm (Figure 7). Two years after the operation, a new graft is patent. CASE 7. A 78-year-old man with previous history of arterial hypertension and higher serum lipid level, has been admitted with an asymptomatic pulsating swelling of the medial portion on the thigh. Seven years ago the bellow knee F-P bypass with ASVG and exclusion of the poplietal artery aneurysm was performed. The Duplex ultrasonography and angiography showed a fusiform true aneurysm formation at the mid portion of the patent graft. The aneurysm has been replaced with femoro-anterior tibial artery bypass procedure using 6 mm PTFE graft. The pathohistological examination showed an atherosclerotic origin of the aneurysm. This patient died five days after the operation due to myocardial infarction with patent graft. CASE 8. A 65-year-old male with previous history of arterial hypertension and higher serum lipid level, had an elective replacement of the popliteal artery aneurysm. For the reconstruction a PTFE graft was used. Two years postoperativelly this graft occluded due to changes on the crural arteries. From these reasons a new bypass from the superficial femoral to anterior tibial artery with saphenous vein graft, was performed. Nine years later she was admitted with painful pulsating mass of the mid portion of the thigh. The Duplex ultrasonography and transfemoral angiography showed patent graft with fusiform aneurysm formation of its mid portion. The ASVG aneurysm was replaced with 8 mm Dacron graft. A pathohistological examination showed atherosclerotic origin of the ASVG aneurysm. One year latter this graft is patent. CASE 9. A 65-year-old male with previous history of arterial hypertension and higher serum lipid level, has been admitted due to disabling claudications discomfort caused by aorto-iliac occlusive disease. Nine years earlier a right sided aorto-renal bypass with ASVG was performed due to occlusive disease and renovascular hypertension. An translumbar aortography showed occlusion of the aortic bifurcation associated with fusiform aneurysm formation of ASVG (Figures 8, 9 and 10). During the same operation an aorto-bifemoral bypass and repairing of ASVG aneurysm with Dacron grafts, were performed. A pathohistological examination showed atherosclerotic origin of the ASVG aneurysm. One year latter both grafts are patent. DISCUSSION The table 1 shows 45 true aneurysmal formation at ASVG after F-P bypass surgery in cases with occlusive diseases [1-25]. In his famous paper Szilagyi [3] reported a study of the biologic fate of ASVG in 260 patients with F-P bypass procedures, and he found 10 (3.8%) aneurysms. In 1973 De Weese [5] found 4 (1.2%) ASVG aneurysms after 350 F-P reconstructions, while in 1975 Vanttinen [6] found 1 (0.9%) such case after these procedures. In 1987 Yuanagyia [26], and in 1989 Martin [27] described cases of ASVG aneurysmal formation after subclavian artery aneurysm replacement. Yanagyia's patient had a Behcet disease. We also had one case of ASVG aneurysm after subclavian artery aneurysm repair, manifested with hand ischemia due to distal embolization. Gemperle[12]in 1986 decribed ASVG aneurysm which developed 18 years after replacement of the injured brachial artery. Carrasaquilla [28] has in 1972 described a case of ASVG aneurysm formation after replacement of the common carotid artery, while in 1998 Tekeuchi et al [29] described a case of an ASVG aneurysm after subclavian to vertebral artery bypass due to stenotic lesions of the both vertebral arteries. Four years later a giant ASVG aneurysm was found, and successfully resected. In 1990 Peer et al [30] reported two ASVG aneurysms seven and eight years after popliteal artery aneurysm replacement. In 1991 Kogel et al [31] described one such case 10 years after primary operation. In 1997 Loftus [32] described 10 new cases of the ASVG aneurysms after popliteal artery aneurysm repair. We had two such cases developed three and five years after primary operation. In three of our cases ASVG aneurysm showed an atherosclerotic origin, while in 3 non atherosclerotic. The exact mechanism of aneurysm degeneration of the ASVG in arterial position is unknown. There is likely a combination of factors including: - mechanical trauma during vein harvesting and operation [9,30]; - weakness at branching sites in the vein [2,9]; - potential weakness in the vicinity of the venous valves due to absence of the circular muscle cuff in the media of the vessel wall [5]; - infection [16]; - trauma caused by bony structures near the graft [18,30]; - arteritis [13,14,26, 27, 30]; - atherosclerosis [2,3,5-11,18,19,21,24,25]; - hemodinamic factors from the arterial pressure [23]; - transmural ischemie injury of the vein wall due to disrupting of the vasa vasorum after removing of the vein segments [28,29,33]; Brody cold this fenomen ?devascularization of the venous graft" [34]; - diffuse nature of this process in patients with multiple aneurysmal changes [20,32] (our cases 2,3,4,6 and 8); - using of the cephalic [9], or superficial femoral vein [1] (case 7); - changed veins (one of our cases). The use of in situ bypass technique for arterial reconstruction would theoretically, minimize endothelial trauma by reducing operative manipulation, preserving vasa vasorum, and eliminating the pressure induced endothelial desquamation that has been associated with mechanical destination of reversed vein graft during their harvest. However, Sassoust [15] in 1986 reported 5 cases of true aneuryms of the ASVG after in situ F-P bypass. After Sassoust's new cases of ASVG aneurysm following F-P in situ bypass surgery were reported [22-24]. CONCLUSION Early ASVG aneurysm formation occurring six months after surgery has been found to be the result of preexisting unrecognized vein wall weakness or injury at the time of harvest, while aneurysm discovered 5 or more years postoperatively, were atherosclerotic in nature. The aneurysms of the ASVG are frequent, at patients with multiple aneurysms of natural arteries. The ASVG aneurysms require active surgical treatment. Then autologous vein grafts are not ?material of choice" for replacement of aneurysmally changed ASVG after peripheral vascular reconstructions.

Infrainguinal aneurysm formation in arterialized autologous saphenous vein grafts

True aneurysm formation in arterialized autologous veins is an unusual complication. We studied a patient with 2 aneurysms occurring in the mid and distal portion of an in situ femoropopliteal bypass. The first aneurysm led to graft occlusion 4 years after the primary intervention, requiring replacement of the ectatic graft segment. The graft was still patent when the patient was examined 7 years after the primary intervention and 3 years after the first aneurysm. In the mid portion of the graft, a true aneurysm measuring 5 by 8 cm had developed. The aneurysm was replaced by a reversed segment of the contralateral greater saphenous vein. Recovery was uneventful. Advanced atherosclerotic changes with extensive intimal fibroplasia, subendothelial cholesterol deposits, and ulcerations were revealed by means of histopathology of the aneurysm wall. Atherosclerosis is considered to be the main cause of aneurysm formation in vein grafts, but a review of the literature suggests the additional etiopathogenic factors should be further investigated.

Atherosclerotic aneurysm formation in an in situ saphenous vein graft

Nonanastomotic aneurysm formation in autogenous vein grafts, although rarely described, has been uniformly associated with advanced atherosclerotic change of the vein wall. In the case reported, histologic examination of an in situ vein graft aneurysm demonstrates obliteration of normal vessel wall architecture by penetrating atherosclerotic plaque. Although these findings do not prove a causal relationship, they do provide additional support for atherosclerosis as an etiologic factor in aneurysm disease.

True aneurysm formation in femoropopliteal autogenous vein bypass grafts: two cases

This paper describes two cases of true atheromatous aneurysm formation within reversed autogenous saphenous vein used for femoropopliteal bypass graft. We note the rarity of this complication and review the literature for true aneurysm formation within vein grafts used for this and other bypass procedures.

Arteriovenous fistulae of the meninges draining into the spinal veins. A histological study of 28 cases

The histological study of 28 cases of arteriovenous fistulae of the meninges draining into spinal veins, previously known as retromedullary arteriovenous malformations, has shown that the shunt is located inside the thickness of the dura mater. It is fed by a normal artery and drains through a single and abnormal vein. Our histological documents lead us to the conclusion that this entity is not a genuine arteriovenous malformation but, in all probability, an acquired lesion.

Degenerative changes of vein grafts in preparation media: preliminary studies by electron microscopy and fibrinolytic autography

Degenerative changes of saphenous vein grafts in four preparation media (heparinized whole blood at room temperature and 4 degrees C, and heparinized normal saline at same temperatures) were examined by scanning and transmission electron microscopy and fibrinolytic autography. Following 60--90 min. storage in heparinized normal saline at room temperature, marked morphological changes were present in the media, accompanied by swelling of the endothelial cells, however the tunica media and adventitia were well preserved even after 120 minutes in all of the four preparation media. The decrease in fibrinolytic activity was comparable to the observed morphological changes. In heparinized whole blood at 4 degrees C, degenerative changes were slow and mostly of a slight nature.

Internal mammary artery versus autogenous vein for coronary artery bypass graft

Aortocoronary venous graft (ACVG) and internal mammary artery graft (IMAG) are currently the two most popular choices for coronary artery bypass. The morphologic alteration and susceptibility to atheromatous degeneration of the IMAG were compared with the ACVG. Six of 12 surviving dogs with IMAGs were fed a hyperlipidemic diet and six were placed on a regular diet. All dogs were sacrificed 3-15 months after surgery. Twelve of 28 long-term surviving dogs with ACVGs were also on hyperlipidemic diets, and all were sacrificed 3-18 months after surgery. Arteriography and electron microscopy were performed in selected cases, and histology was performed in all cases. All long-term IMAGs remained patent; 83 percent (5/6) "regular" diet arteries were normal, with no intimal proliferation, while 33 percent (2/6) "hyperlipidemic" IMAGs had diffuse atheroma. Eighty-two percent of ACVGs revealed significant atherosclerosis. Severity of arteriosclerotic involvement of the ACVG was far greater than that of the native coronary circulation; this was not true for the IMAG.

It may be concluded that (1) in the normolipidemic condition the IMAG undergoes significantly less severe histologic change than the ACVG, (2) both the IMAG and the ACVG are more susceptible to atheromatous change than the native coronary circulation. In these series, patency was not influenced by severity of histologic changes, and no grafts were occluded by virtue of the arteriosclerotic process.