Dysregulated apoptosis in primary varicose veins.

OBJECTIVE: Programmed cell death plays a critical role in various physiological processes. To investigate its possible pathogenic role in primary varicose veins we studied histological changes in surgical specimens from human varicose veins. In varicose and healthy veins, we also determined the number of cells in apoptosis, and investigated mediators regulating the intrinsic apoptotic mitochondrial pathway (Bax and caspase 9). METHODS: A total 23 varicose veins were obtained from 18 patients undergoing lower-extremity varicose vein surgery for primary varicose disorders. We used nine healthy veins obtained from nine patients undergoing distal arterial bypass grafting surgery as controls. The venous segment analysed was the distal part of the greater saphenous vein. Specimens for histological examination were stained with hematoxylin and eosin, trichromic and Victoria blue. Cell apoptoses and mediators of the mitochondrial pathway were detected in the media by immunohistochemistry using antibodies to peroxidase in situ apoptosis, Bax and caspase 9. Results were expressed as indexes for the three antibodies tested. The Mann-Whitney test was used to compare the results obtained in the two groups. RESULTS: Varicose vein specimens exhibited a more disorganised architecture than healthy veins and showed an increased number of collagen fibres and a decrease in the density and size of elastic fibres. All anti-apoptotic antibodies tested detected significantly fewer immunoreactive cells in tissue sections from the media of varicose veins than of healthy veins (peroxidase in situ, varicose veins (VV) median 2.4% (inter-quartile range 1.6-3.9) versus control (C) 14% (IQR 8.8-19); Bax, VV 1.4% (IQR 0.36-2.4) versus C 11% (IQR 7.6-15); and caspase 9, VV 1.7% (IQR 0.06-3.4) versus C 10% (IQR 9.1-12), P=0.0001 (Mann-Whitney test). CONCLUSION: Apoptosis is down regulated in the medial layer of varicose veins. This dysregulation of the cellular mechanism that maintains normal tissue integrity is mediated through the intrinsic apoptotic pathway and may be among the causes of primary varicose veins.

Heparin-induced thrombocytopenia with acute aortic and renal thrombosis in a patient treated with low-molecular-weight heparin.

Heparin-induced thrombocytopenia is a rare but serious complication of heparin therapy. Most of cases are related to unfractionated heparin, but a few are due to low molecular weight heparin sometimes associated with unfractionated heparin. A patient with pulmonary contusions after chest injury developed a catheter related subclavian vein thrombosis on day 16. He was treated by increasing doses of low molecular weight heparin. Aortic and renal thromboses occurred on day 21. Surgical thrombectomy, performed after starting alternative anticoagulation treatment led to complete arterial recovery. In case of suspicion of heparin-induced thrombocytopenia, with unfractionated or low-molecular-weight heparin, heparin treatment must be discontinued before the results of biological tests become available. Arterial and/or venous thrombosis is a serious complication of heparin-induced thrombocytopenia. The treatment has two aims: first, to restore arterial patency by clot removal by thrombectomy, bypass or thrombolysis, and second, to avoid new thrombosis formation by substitutive anticoagulation treatment: danaparoid may have cross-reaction with heparin, or lepirudin has anaphylactic risks and needs biological follow-up. Heparin-induced thrombocytopenia and thrombosis can be complicated by death or disabilities such as amputations, stroke, renal or bowel infarction. Once HIT has been diagnosed heparin should never be given again, but if cardiopulmonary bypass is required, it might be reintroduced during operation only if serum antibodies have disappeared.

Connection between a long-standing traumatic arteriovenous fistula and development of aneurysmal disease.

Long-standing peripheral arteriovenous fistulas (AVFs) are always accompanied by ectasia of the proximal arteries. In the literature, traumatic fistulas of the lower limbs are frequently reported to be associated with iliac and even infrarenal aortic aneurysms; however, no study dealing with associated visceral aneurysms has been published. We report a case in which a traumatic AVF was accompanied by the late development of not only an infrarenal aortic aneurysm but also both superior mesenteric and right renal artery aneurysm. No causal relationship may be inferred between the tibial fistula and the other aneurysms, but this previously unreported finding does raise the question of a possible connection.

Interposition vein cuff and intimal hyperplasia: an experimental study.

OBJECTIVE: There is some evidence to suggest that prosthetic distal bypass graft patency can be improved, and the risk of intimal hyperplasia diminished, by interposing a distal vein cuff. We studied intimal remodeling in an end-to-side distal prosthetic anastomosis constructed with and without a vein cuff. METHODS: Twenty-four prosthetic bypasses were constructed with (N=12) or without (N=12) a distal vein cuff in 12 pigs. At 10 weeks, the 20 anastomoses and adjacent arteries from the surviving 10 pigs were studied by histology, immunohistochemistry and morphometry. RESULTS: Intimal hyperplasia was significantly less on all zones of the arterial floor and all suture zone of arteries anastomosed with a vein cuff than within arteries anastomosed without a vein cuff (0.11 versus 0.34; p=0.001 and 0.35 versus 1.19; p=0.0001, respectively). Intimal hyperplasia was also more prominent within the vein cuff than within the recipient artery, with or without a vein cuff (1.35 versus 0.38; p=0.0001). CONCLUSION: An interposition vein cuff at the distal anastomosis between a prosthesis and an artery alters the distribution of intimal hyperplasia. By acting as an expansion chamber where intimal hyperplasia can develop harmlessly, the vein cuff may protect the arterial anastomosis from stenosis.

Aneurysm of the pancreaticoduodenal arteries with a celiac trunk lesion: current management.

OBJECTIVE: We report a ruptured aneurysm of the pancreaticoduodenal arteries without acute or chronic pancreatitis but associated with a median arcuate ligament division that compressed the celiac trunk, an exceptional event, thus far described in only 11 patients. We also conducted a targeted review to seek information about clinical presentation, to hasten diagnosis and assist in therapeutic management. METHODS: A 54-year-old man with retroperitoneal hemorrhage associated with an arcuate ligament division, documented on computed tomographic scans, underwent diagnostic arteriography and embolization to treat the bleeding aneurysm. In a second elective operation the causative arcuate ligament was sectioned to decompress the celiac artery, to prevent aneurysm recurrence. RESULTS: Embolization stopped the aneurysmal bleeding, and arteriograms showed that surgical sectioning resolved the celiac trunk stenosis. At 1-year follow-up the patient had no signs of complications or recurrence of disease. CONCLUSION: Ruptured aneurysm of the pancreaticoduodenal arteries associated with stenosis of the celiac trunk is a surgical emergency. Although a literature review disclosed no significant difference between outcomes after open surgery and radiologic arterial embolization, our experience in this case suggests immediate embolization during arteriography as the most effective treatment. Later, to prevent recurrence, the arcuate ligament should be surgically sectioned and the celiac artery stenosis treated.

[Superficial femoral artery autotransplantation for popliteal artery damage: a good solution?]. / L'autotransplantation de l'artère fémorale superficielle dans les lésions artérielles poplitées. Une bonne alternative?

We chose not to use a vein to bypass a popliteal artery lesion in four preferring to perform an autotransplantation of a proximal segment of the homolateral superficial femoral artery. The proximal arterial segment translated downstream being replaced by a synthetic graft. This approach was used to treat a popliteal aneurysm in two patients and cystic adventitiel disease in two others. The great saphenous was unfit for bypass in two patients. One patient died with a patent transplant nine Months after surgery due to an unrelated urological problem. The other three patients were alive and symptom free, at least forty-two Months after surgery. All three had a patent transplant despite obstruction of the proximal synthetic bypass in one patient. Provided that the outcome in a larger number of cases confirms these favourable results, we think that this technique offers an attractive alternative to venous bypass, at least whenever a venous graft cannot be used.

[Primary infected aneurysm of the infra-renal aorta:in situ or extra-anatomic bypass?]. / Anévrisme primitivement infecté de l'aorte sous-rénale. Pontage extra anatomique ou in situ?

There is no agreement in the literature as regards the best treatment for primary infected aneurysms. There is agreement concerning in situ treatment, inlay graft for supra-renal aneurysms. For infra-renal localizations no consensus has been reached. Most Authors prefer biological grafts over prosthetic materials for infected grafts or primary infected aneurysms. We report here a case of primary infected aneurysm treated in two stages. An initial axillo-bifemoral bypass was followed one Month later by aneurysmectomy and wide debridement of infected tIssue. Results were good at two years.

Patency and limb salvage after distal prosthetic bypass associated with vein cuff and arteriovenous fistula.

OBJECTIVE: To assess the usefulness of vein cuff with or without arteriovenous fistula interposition as adjuvant techniques for improving patency and limb salvage in patients undergoing femorodistal bypass surgery using prosthetic grafts. METHOD: We undertook a retrospective study of 65 consecutive patients treated over a 5-year period with 67 prosthetic femorodistal bypasses with vein cuff, in whom an arteriovenous fistula was constructed at the distal anastomosis in 35. Patients were followed for a median time period of 23 months. RESULTS: Primary patency rates were 68, 53 and 44% at 1, 2 and 3 years, respectively. The corresponding figures for secondary patency, limb survival and patients' survival were 73, 64 and 58% for 1 year, 78, 76 and 73% for 2 years and 72, 66 and 63% for 3 years. None of the criteria analyzed influenced patency or limb salvage on prosthetic bypasses using adjuvant techniques. No statistical differences were found between patency and limb salvage rates in patients for whom the vein cuff was constructed with or without an arteriovenous fistula. But patients who managed with a supplementary arteriovenous fistula had significantly fewer distal residual arteries in the limb (p=0.001). CONCLUSION: Although results in patients treated with adjunctive techniques differed little from those in patients treated with direct prosthetic bypasses procedures, those who eventually had an adjunctive procedure had inferior runoff. This indicates that an arteriovenous fistula might be a valuable supplement in patients with poor runoff who have distal revascularisation using a prosthetic graft.

Popliteal artery entrapment associated with cannabis arteritis.

OBJECTIVE: To report popliteal artery entrapment in a patient with distal necrosis and cannabis-related arteritis, two rare or exceptional disorders never described in association. To conduct a targeted review and especially to seek information on the clinical presentation with characteristics specific to each disorder so as to hasten the diagnosis and choose appropriate management. MATERIAL AND METHODS: A 19-year-old man who presented with plantar claudication associated with necrosis in a toe underwent diagnostic arteriography and surgery for popliteal artery entrapment type III. RESULTS: Surgical clearance resolved the popliteal artery entrapment but left the clinical symptoms unchanged. Closer questioning disclosed a history of cannabis consumption and intravenous vasodilatory therapy was started. After the 21-day course of vasodilator agents the pain disappeared and the toe necrosis regressed. The patient stopped taking cannabis and had no signs of recurrence. CONCLUSION: Whereas a popliteal artery entrapment, albeit a rare event, is well described and responds to standardized treatment, popliteal artery entrapment associated with cannabis-induced arteritis is an exceptional event that could confuse management. Because young people-the age group mainly at risk for popliteal artery entrapment-increasingly use cannabis, cannabis arteritis could become a more frequent event associated with other arterial disorders that may confuse the diagnosis and complicate management. Our experience in a young patient suggests that coexisting popliteal artery entrapment and distal necrosis in a young patient should raise a strong suspicion of an associated vascular disorder possibly related to cannabis consumption. Intravenous vasodilatation treatment is successful provided that cannabis use is discontinued.

[External ionizing radiation on the prosthesis-arterial anastomosis for the prevention of intimal hyperplasia and study of biomechanical resistance. Experiments and results]. / Radiations ionisantes délivrées par voie externe sur l'anastomose prothéto-artérielle pour limiter l'hyperplasie intimale et étude de la résistance biomécanique. Expérimentations et résultats.

PURPOSE: To evaluate the use of external ionizing radiation for the prevention of intimal hyperplasia in anastomosis between PTFE and artery. METHODS: Bypass using a 6 mm PTFE was performed on a swine subrenal aorta with a distal conventional anastomosis (N = 35) associated (test group; N = 17) or not (control group; N = 18) with post-operative external radiation (20 Gy) on this anastomosis. At 45 days, histological studies and morphometric studies were performed on the aorta receiving the anastomosis. Two protocols were performed, the first protocol with standard analysis and the animals were randomly assigned to either group (test group; N = 11 and control group; N = 13) and the second protocol with test of extraction comparing the biomechanical resistance between the irradiated group (N = 6) and the control group (N = 5). RESULTS: Twenty-one animals survived the procedure in the first protocol, 11 in the second. The endothelium was restored in either group. Histological recasting was observed in the media after radiation with fibrosis and areas of necrosis. Intimal thickness was significantly lower after irradiation in the heel (P < 0.01), the head (P < 0.01) and the suture line (P < 0.001) of the artery in the first protocol. The intimal thickness was also significantly lower in the second protocol after radiation in the heel (P < 0.05) and the head of the artery (P < 0.05). There was no difference between the two groups comparing the resistance. CONCLUSION: After external irradiation, the thickness parameter of the intima decreased significantly in comparison with the control group with similar resistance. Media fibrosis and necrosis need to be confirmed by further investigation.

[Hyperplasia of the arterial intima due to smooth muscle cell proliferation. Current data, experimental treatments and perspectives]. / Hyperplasie intimale artérielle par prolifération de cellules musculaires lisses dans la paroi: données actuelles, traitements expérimentaux et perspectives.

Restenosis after vascular surgery using bypasses or endovascular techniques for dilatation or recanalisation remains the major Achilles' heel for these techniques. The progressive decrease of vessel lumen in an anastomose leading to graft failure or after arterial transluminal angioplasty is due to a complex process: intimal hyperplasia. This process can be compared to an hypertrophic healing into the intimal layer, reducing the lumen of the vessel. This process appears shortly after surgery or dilatation, between the 3rd and the 18th month. Mechanisms leading to this process are particularly complex, involving several cells and many regulatory processes still unclear. Smooth muscle cells are the main actor by their ability to proliferate and to secrete matrix into the media layer but stimulation and control of this process appear nevertheless complicated. The present review focuses on the pathophysiology of intimal hyperplasia, on different cells acting and on their regulation. Also, we reviewed the experimental and clinical trials evaluating approaches to the prevention of intimal hyperplasia in arteries.

[High-dose external ionizing radiation prevents intimal hyperplasia and limits secretion of growth factors PDGFbb, bFGF, and TGFb1. Experiments and results]. / Les radiations ionisantes externes à doses élevées limitent l'hyperplasie intimale et diminuent la sécrétion des facteurs de croissance PDGF-bb, bFGF et TGFb1. Expérimentation et résultats.

PURPOSE: To evaluate the ionizing radiation for intimal hyperplasia prevention and to assess the production of growth factors. METHODS: An oversized injury using an embolectomy catheter was performed on a rabbit distal aorta (N=23), associated (test group; N=12) or not (control group; N=11) with a post-operative external radiation (25 Gy). At t=45 days, histological studies and morphometric studies were performed on the aorta. Smooth muscular cells and endothelial cells were stained using immuno-histologic revelation. Immuno-histological analysis was performed on arteries for growth factors PDGFbb, bFGF and TGFb1. RESULTS: Twenty-one animals survived the procedure, 11 were in the test group and 10 in the control group. Intimal thickness and ratio intima/media were significantly lower after radiation (respectively p=0.008, p=0.008). There was no difference for the medial thickness (p=0.155). Immuno-histochemical positive staining for PDGF and TGFb1 was lower after radiation (respectively 18.44 +/- 2.963% versus 47.64 +/- 6.86%, p<0.001 and 10.11 +/- 3.18% versus 29.45 +/- 4.156%, p<0.001). There was no difference for the expression of bFGF growth factor. After radiation, the media was found to be reduced and replaced by interstitial fibrosis. CONCLUSION: After external radiation the thickness parameter of the intima and the ratio intima/media decreased significantly in comparison with the control group. PDGF and TGFb1 were also less expressed in the artery irradiated. Fibrosis recasting needs to be confirmed by further investigation.

[Arterial complications of thoracic outlet syndrome and pseudarthrosis of the clavicle: three patients]. / Complications artérielles du syndrome du défilé thoraco-brachial et pseudarthrose de clavicule: à propos de trois patients.

During a 3-year period, three patients developed arterial complications related to congenital or post-traumatic old pseudarthrosis of the clavicle. Arterial complications of pseudarthrosis of the clavicle presenting as a thoracic outlet syndrome are very rare. Symptoms are variable and occur late. Without treatment, the prognosis is poor with spontaneous development of gangrene. Arterial morphology investigations should be undertaken in patients with pseudarthrosis of the clavicle or isolated arterial symptoms involving the upper limb whose radial pulse disappears during postural tests. Duplex Doppler of the subclavian artery is an excellent screening exam but selective arteriography is the gold standard. It shows proximal arterial lesions (embolytic stenosis of the subclavian artery with post-stenotic dilatation), as well as distal embolic complications. Both static and postural tests must be performed to unmask subclavian restriction by the clavicle, proving its causal effect in the arterial complications. There are four clinical varieties: chronic thrombosis of the subclavian artery, distal arterial micro emboli, acute thrombosis of proximal arteries of the upper limb, and subclavian aneurysm. These lesions are thought to be due to chronic constriction and repeated arterial microtrauma. Congenital or post-traumatic pseudarthrosis, hypertrophic callus, arterial restriction by a screw in a clavicular plate, usually explain the arterial lesions. Bone tumors and Paget's disease are potential but exceptional clavicular etiologies. Surgical treatment is always necessary. Clavicular resection is usually needed in case of pseudarthrosis; there is no functional handicap. Plate fixation and autologous grafting, or open reduction and internal fixation are other valid surgical treatments; The embolytic lesions must be treated to prevent recurrence of distal embolization: graft resection and thromboendarteriectomy have been described. Neurological and venous decompression may be associated at the same time. Complementary treatment can be associated: distal bypass, cervicothoracic sympathectomy, in situ thrombolysis or thrombectomy. Endovascular treatment is not indicated. Optimal treatment of clavicular fractures is required to prevent the development of thoracic outlet syndrome.

[Non-penetrating vascular staples prevent myo-intimal hyperplasia and maintain arterial vasomotor reaction]. / Les clips de suture vasculaire non pénétrants limitent l'hyperplasie myo-intimale et maintiennent les réactions artérielles.

OBJECTIVES: Vascular anastomosis is still associated with a significant rate of early or delayed complications, particularly restenosis. We have previously demonstrated that non-penetrating clips can help prevent intimal hyperplasia. The aim of this study was to evaluate how well the use of mechanical clips prevents intimal hyperplasia while maintaining arterial vasomotor function. MATERIAL AND METHODS: An aortic suture was performed in 38 rabbits. A standard closure was used for 15 sutures and a small vascular closure staple (VCS) for 23. Morphological analysis was performed with standard staining, histomorphometry and immunochemical staining for smooth muscle and endothelial cells. Vasomotor response was assessed using IntraVacularUltraSound with baseline luminal area and luminal area after injection of acetylcholine and nitroglycerin. Vasomotor response was assessed before suture and before removing the aorta. RESULTS: There was a significant improvement in operating time for closure with vascular staples (8 +/- 2 minutes versus 13 +/- 3 minutes) without thrombosis. We noted reduced intimal hyperplasia with staple closure (0.156 +/- 0.052 versus 0.087 +/- 0.042 mm, p<0.01). There was no difference for the medial thickness and the intima/media ratio was significantly different. The luminal area after suture was significantly better after vascular staple closure (16.78 +/- 0.639 mm(2) versus 17.24 +/- 0.492 mm(2), p=0.016). Vascular response to acteylcholine and nitroglycerin was equivalent for the two groups. CONCLUSION: Vascular closure staples are efficient for arterial closure. These non-penetrating systems prevent intimal hyperplasia and maintain physiological arterial vasomotor response.

[Ionizing radiation and hyperplasia of the intimal matrix: current data and perspectives]. / Radiations ionisantes et maîtrise de l'hyperplasie intimale.

Vascular reconstruction (bypasses or endoluminal procedures) is still associated with a significant rate of restenosis. For restenosis, smooth muscular cells are the principal actor by their property to migrate, proliferate and secrete extra-cellular substance after their change of phenotype. A variety of pharmacological and mechanical strategies have been directed with limited success. Using ionizing radiation have been recently developed, aiming to reduce the cell proliferation and consecutive restenosis following vessel injury (anastomoses or angioplasty). We reviewed the use of radiations on animals, cellular action and recent clinical trials. Recent clinical trials confirm an effective action of using radiations for restenosis prevention. We reviewed methods of delivering radiations also drawback and consequences using these hopefully methods.

[Can minimal arterial aggressions using non-penetrating mechanical clip suture prevent myo-intimal hyperplasia? Preliminary results]. / L'agression artérielle minimale lors de suture par clips mécaniques non pénétrants prévient-elle l'hyperplasie myo-intimale? Résultats préliminaires.

SUBJECT: Vascular anastomosis is still associated with a significant rate of early (stenosis, thrombosis) and delayed (intimal hyperplasia) complications. Even though suture closure remains the most widespread standard procedure, many mechanical systems have been developed mostly using non penetrating clips, aiming to make the suture easier, to reduce the operating time and to reduce the scarring process of the arterial wall. We investigated the usefulness of non penetrating titanium Vascular Closure Staple (VCS) developed for peripheral blood vessels anastomosis, in a study on 20 rabbits with the small VCS system. MATERIAL AND METHODS: On 20 rabbits, 9 of the aortic sutures were done with VCS clips and 11 were done by standard closure. RESULTS: We found a significant improvement in the operating time of the closure (9 +/- 2 minutes versus 14 +/- 4 minutes), early and delayed (10 weeks) patency and the respect of the aorta diameter (0.248 +/- 0.01 centimetres versus 0.246 +/- 0.039 centimetres) and loss of surface (40.3 +/- 5.59% versus 45.6 +/- 6.34%). The main improvement is the reduced intimal hyperplasia (0.128 +/- 0.05 millimetres versus 0.198 +/- 0.032 millimetres. P=0.012). CONCLUSION: Arterial closure can be performed more rapidly with VCS clips than with suture closure, and with a marked reduced reaction of intimal hyperplasia. With those elements it is necessary to continue the experimental studies and to evaluate the VCS sutures at mean and long term.

[Homolateral transposition of the internal jugular vein for axillo-subclavian venous thrombosis (of effort)]. / Transposition veine jugulaire interne homolatérale pour thrombose veineuse axillo-sous-clavière (d'effort).

UNLABELLED: Indications for treating subclavian vein obstruction are still being developed, especially for endovascular procedures with or without first rib resection. This article explores our experience with chronic and acute subclavian vein thrombosis persisting after medical treatment. In our department of vascular surgery, we have observed 2 cases of subclavian vein obstruction in 2 patients with Paget-Schroetler syndrome who developed major pain and edema in the dominant upper limb. Initially, we managed these patients medically with thrombolysis and anticoagulation. Then, as the significant symptoms persisted and venous thrombolysis developed, we decided on surgical treatment. Because of hypertrophic venous impairment, we used an aggressive procedure with venous bypass using jugular vein transposition and temporary arteriovenous fistula. We observed significant symptom relief and also perfect permeability of the venous bypass at 30 months. CONCLUSION: On the basis of our anecdotal experience and reports by other groups, aggressive treatment with decompression (first rib resection and scalenectomy) and jugular vein transposition could be recommended for persistent subclavian vein thrombosis. Because of the presence of a thoraco-brachial outlet syndrome the endovascular procedures should be completed by first rib resection.

[Evaluation of the venous network before arterial revascularization surgery]. / Evaluation du capital veineux avant chirurgie de revascularisation artérielle.

Correct evaluation of the venous network before arterial revascularization is required to avoid unsuccessful explorations, underestimation of calibre because of spastic reactions to dissection and use of defective veins with unrecognized parietal or intraluminal lesions. The homolateral internal saphenous vein cannot be used in 10 to 30% of cases. Success of venous bypass is 30 to 40% greater than with prosthetic implants. Other veins can be used including the contralateral internal saphenous vein, external saphenous veins and veins from the upper limbs. Clinical evaluation is insufficient. Phlebography provides good results but is an aggressive exploration with certain limitations compared with duplex Doppler. Its potential complications are also absent with ultrasound exploration. Duplex Doppler is thus the first-line choice. Close coordination between the angiologist and the surgeon is essential to compare the exact measurements obtained preoperatively and the surgical findings, particularly concerning the venous calibre. Correction coefficients may then be established.

[Chickenpox and limb ischemia. Report of a case]. / Varicelle et ischémie de membre. A propos d'un cas.

We have observed in our department a subacute left inferior limb ischemia by a forty one years old man in the following of a chicken pox while big arteries (arteria profunda femoris, lateral plantar artery, arteria dorsalis pedis) were attacked. We have not noticed in the medical literature such a case described. We have treated this ischemia by an in situ fibrinolysis which lead to a total clinical recovery, a complete patency of the lateral plantar artery and the arteria dorsalis pedis, and an incomplete patency of the arteria profunda femoris. We expose a few physiopathological hypothesis. But, in any case, we have not the proof of a connection between ischemia and the viral infection.

[Fibrous hyperplasia in femoro-popliteal bypasses using treated human umbilical veins]. / Hyperplasies fibreuses sur pontages fémoro-poplités par veines ombilicales humaines traitées.

The authors report two clinical cases of the failure due to fibrous hyperplasia of processed human umbilical vein (HUV) grafts employed as femoro-popliteal bypasses. Failure occurred after 19 months implantation at the proximal anastomosis for one graft and after 10 months at the distal anastomosis for the other. Fibrous hyperplasia was the principal cause of reoperation. The lightly vascularized, more or less compacted fibrin involved, adhering loosely to the HUV, remains thrombogenic at the blood-contacting surface. Superposed onto this phenomenon which is widespread in laboratory animals but uncommon in humans, are the usual causes of failure: delamination of the HUV wall, lipid uptake and bacterial colonization.