Suitable Autologous Vein Research Articles

Comparison of Outcomes for Open Popliteal Artery Aneurysm Repair Using Vein and Prosthetic Conduits

Autologous vein is considered the preferred conduit for lower extremity bypass. There is, however, limited literature regarding conduit choice for open popliteal artery aneurysm (PAA) repair. We sought to compare outcomes of PAA repair using vein versus prosthetic conduits. The Vascular Quality Initiative database (2003-2019) was queried for patients with PAAs undergoing elective conventional revascularization originating from the superficial femoral and popliteal arteries. Conduits were categorized as vein or prosthetic. Primary outcomes were primary graft patency, freedom from major adverse limb event (MALE) and MALE-free survival at 2-years. Kaplan-Meier method with log-rank tests was used for estimation and comparison of patency. A total of 1,146 limbs in 1,065 patients underwent elective open revascularization for PAA. Vein was used in 921 limbs (80%), and prosthetic in 225 (20%). Patients in the prosthetic cohort had a shorter procedure time, were older, and had a higher prevalence of COPD. Postoperatively, prosthetic patients were more likely to be started and maintained on anticoagulation without increased incidence of hematoma. There was no significant difference in the rate of surgical site infection (2% vs. 2%; P = 0.946). There was an increased tendency toward more symptomatic patients in the vein cohort although not statistically significant (49% vein vs. 41% prosthetic; P = 0.096). On a mean follow-up of 13 ± 5 months, the incidence of MALE and MALE-free survival were comparable between the two groups. The 2-year primary and secondary patency rates were similar, 87% and 96% in the vein, and 91% and 95% in the prosthetic groups, respectively. At multivariable analysis, outflow bypass targets to the infrapopliteal arteries (HR 2.05; 95% confidence interval (CI), 1.16-3.65; P = 0.014) and symptomatic aneurysm (HR 1.81; 95% CI, 1.04-3.15; P = 0.037) were independently associated with loss of primary patency. Conduit type did not make a difference in MALE-free survival, or primary graft patency at 2-years. Our study demonstrates that conventional open PAA repair with prosthetic conduit yields results comparable to those with vein conduit with regard to primary and secondary patency and MALEs at 2-years for targets to the popliteal artery. However, when the distal target was infrapopliteal, worse outcomes were observed with prosthetic conduit. Our results suggest that vein conduit should be preferentially used for infrapopliteal targets, while prosthetic conduit confers comparable outcomes in a subset of patients who do not have suitable autologous vein conduits.

Simultaneous SFA Angioplasty/Stent Plus Popliteal Distal Bypass for Limb Salvage

Introduction: Treatment of severe critical limb ischemia (CLI) due to Superficial Femoral Artery (SFA) and below-the-knee (BTK) vessels' involvement could be compromised by the lack of a Great Saphenous Vein (GSV) suitable in its entire length. The purpose of this study is to assess the efficacy of a hybrid endovascular and open lower limbs arterial reconstruction in these patients with multilevel, advanced CLI. We combined two different techniques, each one largely validated for different level of intervention (endovascular for SFA, surgical for BTK), and we aimed to assess the efficacy of such an hybrid arterial reconstruction in patients with multilevel CLI in the lack of suitable autologous vein. Methods: From 2005 to 2019, we performed hybrid endovascular and surgical treatment for limb salvage in SFA-BTK CLI. This consisted of percutaneous transluminal angioplasty (PTA) with or without stenting of the SFA, along with distal origin vein graft bypass. Inclusion criteria were: Rutherford category 5 or 6, lack of a suitable GSV, patency of the popliteal artery, steno-obstructive lesions of the SFA, lesions of the three crural vessels > 5 cm in length each. The follow-up was performed with duplex scan surveillance of both the bypass graft and PTA sites. Results: The hybrid treatment was performed in 34 patients. 56% of the SFA steno-obstructive lesions were treated with simple PTA, except for the application of a bare metal stent in one patient (3%), while in all the SFA occlusions PTA was completed with covered stents (41%). Thirty-four popliteal-to-distal vein bypass grafts have been performed. There were no perioperative PTA or bypass graft failures. Clinical improvement was achieved in 26 (76%) patients. Overall, primary, assisted primary and secondary patency, limb salvage, and survival rates were 65%, 70%, 68%, and 75% at 5 years, respectively (Graph 1 and Graph 2). Conclusion: A hybrid strategy in multilevel SFA-BTK CLI is a well established approach. Additional studies are warranted to validate these results.Graph 2View Large Image Figure ViewerDownload Hi-res image Download (PPT) Disclosure: Nothing to disclose

Comparative study between cryopreserved arterial allografts and heparin-coated grafts for below the knee bypasses for critical limb ischemia

The aim of this study was to compare cryopreserved arterial allografts (CAA) with heparin-coated grafts (HCG) for below the knee bypasses carried out in patients presenting with critical limb ischemia (CLI) in the absence of a suitable autologous saphenous vein.

A Randomized Controlled Trial Comparing Crude Versus Heparin-Bonded PTFE Graft in Below the Knee Bypass Surgery for Critical Limb Ischemia (REPLACE Trial): Design and Protocol

Although autogenous venous grafts are preferable for below-the-knee bypass surgery in patients with critical limb ischemia, some 20% of patients will have no suitable vein for grafting, compelling a resort to artificial graft materials. Retrospective subgroup analyses within published studies comparing heparin-bonded polytetrafluoroethylene (PTFE) with crude PFTE graft in below-the-knee bypass suggest that heparin-bonded graft offers superior long-term patency rates, but this has not been prospectively verified in patients with critical limb ischemia. A single-blind randomized controlled trial in 20 French centers has been designed. Patients assessed as having no suitable autologous vein for bypass grafting for critical lower limb ischemia will be randomized to receive either a heparin-bonded PTFE graft or a crude PTFE graft. A literature review suggested expected 1-year patency rates of 53% for the crude ePTFE arm and 74% for the heparin-bonded PTFE arm. On analyzing 1-year patency rate as a binary variable, for a significance level α = 0.05 and a randomization ratio of 1:1, a total of 176 patients (88 in each arm) will be required to obtain approximately 80% power to reject the null hypothesis. Assuming 10% dropout at 1 year and 20% mortality, 228 patients will be randomized (114 patients in each arm). The primary outcome variable will be patency at 1 year assessed by duplex ultrasound color-flow scan. Any intervention to open up or prevent a graft occlusion before 1 year will be classified as loss of patency. Technical success, deaths, complications, major adverse cardiovascular and limb events, length of hospitalization, and quality of life will also be recorded and analyzed as secondary outcome variables. Cost-utility and cost-effectiveness analyses based on standard tariffs in the French health insurance system will be performed. The REPLACE trial is the first randomized controlled trial designed to determine if heparin-bonded PTFE graft is superior to crude PTFE graft in below-the-knee bypass surgery for critical limb ischemia.

Distal vein patch use and limb events after infragenicular prosthetic bypasses

ObjectiveIn the absence of suitable autologous vein, the use of prosthetic grafts for infragenicular bypasses in peripheral arterial disease has become standard practice. The purpose of this study was to investigate whether creating a vein patch at the distal anastomosis would further improve patency and freedom from major adverse limb events (MALEs). Furthermore, we sought to investigate whether the use of a distal vein patch (DVP) was associated with lower rates of acute limb ischemia (ALI) for those presenting with occluded prosthetic bypass graft. MethodsThe cases of all patients undergoing infragenicular prosthetic bypass grafts between January 2009 and July 2016 were retrospectively reviewed. Demographics of the patients, clinical data, and outcomes (graft patency and MALEs) were collected. Patients were compared according to treatment group (DVP vs no DVP). A Cox regression analysis was used to analyze follow-up results. ResultsDuring the study period, a total of 373 patients underwent infragenicular bypass at our institution; of those, 93 (24.9%) had prosthetic grafts (DVP, 39; no DVP, 54). Overall, 92 (98.9%) patients were male; the mean age was 63.3 ± 6.6 years and did not differ between the two groups. Patients undergoing prosthetic bypass with DVP were more likely to have chronic obstructive pulmonary disease (38.5% vs 14.8%; P = .009) and less likely to have chronic kidney disease (2.6% vs 20.4%; P = .011). Follow-up data were available for all patients for a median of 7.8 months (range, 1-89 months). After adjustment for differences in demographics and clinical data between the two groups, when outcomes were analyzed, MALEs were significantly lower in the DVP group (35.9% vs 57.4%; odds ratio [OR], 0.4; 95% confidence interval [CI], 0.2-0.9; P = .041). Similarly, reintervention rates were significantly lower in the DVP group (30.8% vs 50.0%; OR, 0.4; 95% CI, 0.2-0.9; P = .044). There was a trend toward higher primary patency in the DVP group (46.2% vs 35.2%; OR, 1.5; 95% CI, 0.7-3.5; P = .206) and lower rates of ALI after bypass occlusion (30.0% vs 42.9%; OR, 0.6; 95% CI, 0.2-1.8; P = .345). A Cox regression time-to-event analysis revealed late separation of freedom from MALEs for DVP relative to no DVP (log rank, P = .269). ConclusionsIn this evaluation of infragenicular prosthetic bypass grafts, the creation of a vein patch at the distal anastomosis was associated with lower reintervention rates and a trend toward improved primary patency and MALEs. Furthermore, for those presenting with occluded prosthetic bypass graft, the use of a DVP was associated with a trend toward lower rates of ALI.

Interposition vein cuff for infragenicular prosthetic bypass graft

The use of prosthetic grafts such as polytetrafluorethylene (PTFE) or Dacron to bypass occluded arteries in the lower leg is an accepted practice in the absence of suitable autologous vein. The aim is limb salvage or functional improvement in critical limb ischaemia, but patency rates for below knee prosthetic bypasses are low. Creating a vein cuff at the distal anastomosis is thought to improve outcomes. Other techniques including the use of pre-cuffed synthetic grafts, spliced segments of vein and the creation of an arterio-venous fistula (AVF) are also used to improve patency. To compare the beneficial effects of using vein cuffed prosthetic grafts for below knee bypass in critical limb ischaemia with other types of reconstruction. The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched May 2012) and CENTRAL (2012, Issue 5) for publications comparing prosthetic infragenicular bypass using vein cuffs with other bypass techniques. Randomised controlled trials comparing interposition vein cuff prosthetic graft with autologous vein graft and non-cuffed prosthetic graft for infragenicular bypass in patients with critical limb ischaemia were included. Trials comparing vein cuff prosthetic grafts with or without AVF and vein cuff prosthetic grafts with pre-cuffed prosthetic grafts were also included. The trials were selected and assessed independently by two review authors. Six trials with a combined total of 885 patients were included in this review. Only studies using prosthetic PTFE grafts were identified.Two trials compared PTFE graft with or without a vein cuff. In one underpowered trial for below knee bypass the cumulative primary patency rate was statistically significantly higher in the vein cuff group (80.3% versus 65.3% at 12 months and 51.8% versus 29.1% at 24 months, P = 0.03). There was no statistically significant difference in secondary patency (82.9% versus 72.5% and 58.6% versus 34.9%, P = 0.14) and limb salvage rates (86.3% versus 71.8% and 82.6% versus 62.2%, P = 0.08) at 12 and 24 months respectively. The other trial showed no statistically significant difference between the groups at three years in the below knee femoro-popliteal bypasses (primary patency rate 26% (95% confidence interval (CI) 18 to 38) and 43% (95% CI 33 to 58), secondary patency rate 32% (95% CI 23 to 44) and 42% (95% CI 31 to 56) and limb salvage rate 64% (95% CI 54 to 75) and 61% (95% CI 50 to 74) in the collar and no collar groups respectively). In the femoro-distal bypass group, the differences in primary patency, secondary patency and limb salvage rates were also not statistically significant at three years (primary patency rate 20% (95% CI 11 to 38) and 17% (95% CI 9 to 33), secondary patency rate 22% (95% CI 12 to 39) and 20% (95% CI 11 to 35) and limb salvage rate 59% (95% CI 46 to 76) and 44% (95% CI 32 to 61) in the collar and no collar groups respectively).One trial compared pre-cuffed PTFE grafts with vein cuffed grafts. There was no statistically significant difference in primary patency rate (62% pre-cuffed PTFE versus 52% vein cuff PTFE and 49% versus 44%, P = 0.53), secondary patency rate (66% pre-cuffed PTFE versus 53% vein cuff PTFE and 55% versus 50%, P = 0.30) or limb salvage rate (75% pre-cuffed PTFE versus 72% vein cuff PTFE and 62% versus 65%, P = 0.88) at 12 and 24 months respectively.One trial compared spliced vein grafts with vein cuffed PTFE grafts. At 24 months, the secondary patency rate was statistically significantly higher in the spliced vein group (86% in the spliced vein and 52% in the vein cuff group, P < 0.05). There was no statistical significant difference in primary patency rate (44% versus 50%, P > 0.05) and limb salvage rate (94% versus 85%, P > 0.05).Two trials compared vein cuff PTFE grafts with and without AVF. There was no statistical significant difference at 24 months in primary patency rate (29% versus 36%, P = 0.77; 32% versus 28%, P = 0.2), secondary patency rate (40% versus 40%, P = 0.89; 28% versus 24%, P = 0.2) and limb salvage rate (65% versus 70%, P = 0.97; 62% versus 71%, P = 0.3). There is evidence that a vein cuff at the distal anastomosis site improves primary graft patency rates for below knee PTFE graft, but this does not reduce the risk of limb loss. Pre-cuffed PTFE grafts have comparable patency and limb salvage rates to vein cuff PTFE grafts. The use of spliced veins improved secondary patency but this did not translate into improved limb salvage. The use of an AVF alone showed no added benefits. Evidence for a beneficial effect of vein cuffed PTFE grafts is weak and based on underpowered trials. A large study with a specific focus on below knee vein cuff prosthetic grafts, including PTFE, is required.

Subintimal angioplasty in femoropopliteal region—Mid-term results

Purpose Subintimal angioplasty is becoming more frequently used treatment option for patients with long arterial occlusions or diffuse atherosclerotic changes as an alternative to surgical treatment in claudicants especially in patients with critical limb ischemia. The aim of our article is to retrospectively assess mid-term outcomes of subintimal angioplasty of chronic arterial occlusions in femoropopliteal region followed clinically and by Doppler ultrasonography. Materials and methods From May 2002 to December 2007, 133 femoropopliteal artery occlusions in 123 patients were indicated for subintimal recanalisation. The indications for treatment were intermittent claudications in 84 patients (63.15%) and critical limb ischemia in 49 patients (36.85%). The median length of lesions was 11.4 cm, range 2–30 cm. Except doppler ultrasonographic examination done 24 h after the procedure and clinical examination before discharge, both clinical and ultrasonographic examinations were performed 6 and 12 months after the procedure and yearly thereafter. Statistical analysis of our cohort was performed by Kaplan–Meier analysis, log-rank test and Cox regression. Results Technical success was achieved in 86.46%. Primary patency rate was 83.1% (SE: 3.9%), 67.5% (SE: 5%), 58% (SE: 5.9%) a 48.4% (SE: 7.1%) at 6, 12, 24 and 36 months respectively. No statistically significant difference of primary patency was found between the group of claudicants and the group of patient with critical limb ischemia. Statistically significant prediction factors for primary patency were only the quality of the run off and the length of the occlusion. Limb salvage rate in our group of patients with critical limb ischemia was 80.8% at 12 months. Conclusion : Subintimal recanalisation is a simple and safe procedure for treatment of chronic peripheral arterial occlusions with high primary technical success rate, acceptable primary patency rate, low percentage of complications and mortality is as low as nil. Subintimal angioplasty is definitely advantageous and fast method in patients with critical limb ischemia with high possibility of limb salvage. Surgical treatment can be replaced by subintimal angioplasty in claudicants with high risk of operative treatment, without suitable autologous vein graft or where distal femoropopliteal or femorocrural bypass is needed.

Early Results for Below-Knee Bypasses Using Distaflo

In patients who require lower extremity revascularization, prosthetic graft is a reasonable alternative in the absence of a suitable autologous vein conduit. However, prosthetic bypass grafts have limited patency, especially for infrageniculate reconstruction. Polytetrafluoroethylene grafts were geometrically modified at the distal end to increase their patency. The authors reviewed their experience with the Distaflo graft in patients who required lower extremity below-knee popliteal and tibial bypasses when no suitable autologous vein conduit was available. Chart review was conducted of the 57 patients who underwent 60 lower extremity bypasses over a 3-year period between June 2003 and April 2006. Twenty-four revascularizations were constructed to the tibial outflow sites, whereas the remaining grafts were placed to the below-knee (28) and above-knee (8) popliteal artery, respectively. Study endpoints were primary, assisted primary, secondary patency, and limb salvage at the time of follow-up. Distaflo bypass was performed at the infrageniculate level in 86.7% of cases (28 below-knee popliteal, 24 tibial). Mean follow-up time was 12 months (range, 0.5-37.5 months). At 1 year, primary, assisted primary, and secondary patencies and limb salvage rates for below-knee popliteal bypasses were 83.5%, 89.5%, 94.7%, and 94.4%, respectively. Primary, assisted primary, and secondary patencies and limb salvage rates for tibial bypasses were 44.4%, 44.4%, 63.2%, and 74.9%, respectively. Distaflo precuffed graft is a good alternative conduit for below-knee popliteal and tibial lower extremity reconstructions in the absence of an autologous vein and appears to have promising early patency and limb salvage rates even when used for tibial bypasses.

Early thrombosis in bovine mesenteric vein grafts after infrainguinal reconstruction

Autologous vein grafts are still the gold standard in infrainguinal arterial bypass grafting procedures. However, due to the unavailability of suitable autologous vein grafts, heterogeneous grafts are usually preferred. In the present study, surgical outcomes with bovine mesenteric vein grafts (ProCol, Hancock Jaffe Laboratories, USA) in the infrainguinal location in patients with ischemic leg infection or necrosis are presented. Seven patients who underwent infrainguinal arterial reconstructions with ProCol grafts were evaluated retrospectively. Graft thrombosis was seen in two patients on postoperative day 1 (28.5%). The shortest and the longest patency durations were six and 18 months, respectively. Aneurysmal dilation developed postoperatively in two grafts (28.5%) after 12 and 18 months, respectively. In cases where infection accompanies ischemia, and autologous veins are not available as graft materials, ProCol grafts can be used as temporary grafts in infrainguinal arterial reconstructions. The use of the graft is believed to be unacceptable for any indication other than infection due to its low short- and long-term patency rates and high risk of aneurysm formation in this location.

Homograft patch repair in carotid artery rupture

The case of a 24-year-old man with a rupture of the left common carotid artery and history of intravenous drug abuse is presented. Due to absence of a suitable autologous vein segment the carotid bulb was repaired with a human allograftpatch.

Early Results of Lower Extremity Infrageniculate Revascularization with a New Polytetrafluoroethylene Graft

When an autologous vein is not available for lower extremity revascularization, prosthetic grafts are often required. However, prosthetic bypass grafts have limited patency for infrageniculate reconstruction. To potentially improve patency, a new geometric modification of the polytetrafluoroethylene (PTFE) graft, Distaflo (Impra, Tempe, AZ), has been developed for lower extremity bypass. We reviewed our early experience with the Distaflo graft in patients who required infrageniculate bypass for lower extremity ischemia when no suitable autologous saphenous vein was available. All patients were maintained on warfarin anticoagulation postoperatively. All grafts were followed at 6- to 12-week intervals with duplex ultrasound evaluation. Patient characteristics, operative procedures, and graft surveillance information were maintained on a computerized registry. Thirty-two patients with limb-threatening ischemia underwent 35 infrageniculate reconstructions with a Distaflo graft between February 26, 1999, and August 24, 2000. Thirty-two of 35 bypasses were performed on extremities that had previously undergone a surgical procedure. Forty-eight previous revascularization procedures were done on these 25 extremities. Thirty grafts were constructed to the tibial outflow sites, whereas the remaining five grafts were placed to the below-knee popliteal artery. One patient died on the second postoperative day secondary to unrelated causes, and only one graft (3%) failed during the same hospitalization. Fifteen of 35 grafts (43%) remained patent 1 to 30 months later. Four patent grafts (6%) were ligated between 2 and 14 months for infectious indications. When considering the 20 failed grafts, 9 patients underwent major amputation, 5 patients remain with chronically ischemic limbs, and 6 patients underwent additional bypass grafts. Twenty-three patients (72%) maintained limb salvage. The Distaflo PTFE graft achieves promising early patency for complex infrageniculate revascularization and may be used as an alternative conduit in patients with critical limb ischemia who do not have an adequate vein for lower extremity revascularization.

Gefäßverletzungen in der täglichen Praxis

It was the objective of this retrospective study to analyse the causes of injury, surgical approaches, outcome, and complications in patients with vascular trauma and to report our experience with vein homografts for arterial reconstruction in the upper and lower limbs and cervicothoracic region in patients operated on over a period between 1981-2001. In 128 patients with peripheral arterial injuries the mechanism was direct penetration in 90 cases and blunt injury in 20 cases. In 4 cases a chronic damage (false aneurysm, AV fistula) was observed. Isolated vascular trauma was present in 97 patients (75.8%), 31 cases (24.2%) were aggravated by concomitant bone fractures, and nerve or soft tissue damage. Most frequently injured vessels were the superficial femoral (22.6%), crural (22.6%), and ulnar and radial (13.2%) arteries. 16 patients with penetrating cervicothoracic arterial injuries were registered during this period. 8 patients underwent emergency exploration and 8 patients angiography prior urgent exploration. Saphenous vein interposition grafting was applied with good results in 34 patients, polytetrafluoroethylene and Dacron grafts were used in eight cases, end to end anastomosis in 12 cases, venous bypasses in 5 cases, venous patches in 7 cases. 17 patients underwent arterial repair and 9 venous repair. Vein homografts as an arterial substitute were implanted in 8 patients. Five secondary amputations were performed and five patients died. The limb salvage rate was 95% and the primary patency rate of vein homografts was 75% (excluded primary amputations). The penetrating cervicothoracic injuries were all repaired with improvement in level of consciousness and neurological deficit when present. Most vascular injuries of the extremities can be managed successfully unless associated with severe concomitant damage of the bones, nerves and soft tissues. In the absence of suitable autologous vein grafts, homografts appear to be an interesting alternative for arterial repair. In penetrating cervicothoracic vascular injuries immediate operative repair offers the best chance of recovery.

Accelerated endothelialization of interpositional 1-mm vascular grafts

Background There is an increased need for alternative, synthetic, small-diameter vascular grafts due to a growing segment of the population who suffer from ischemic heart disease and lack suitable autologous vein grafts for use in coronary artery bypass grafting (CABG). We hypothesized that a cell-mediated extracellular matrix (ECM) modification of ePTFE would stimulate increased vascularization within the graft and thus promote lumenal endothelialization in a 1-mm rat abdomenal aortic implant model. Methods and results Expanded polytetrafluoroethylene (ePTFE) vascular grafts (1 mm i.d.) were modified on the ablumenal surface with ECM deposited by the HaCaT or II-4 cell lines and implanted intrapositionally into the descending aorta of rats. Five weeks after implantation, all samples were patent and examination of the grafts demonstrated that the ECM modified samples exhibited extensive ablumenal vascularization and tissue incorporation compared to nonmodified samples. Also, ECM modified grafts had a cellular lining, while the nonmodified grafts were void of a cellular lining except for a limited pannus ingrowth. Conclusion HaCaT and II-4 cell ECM modifications of ePTFE increase new blood vessel growth in association with the graft, and the II-4 cell modification results in formation of an endothelial monlayer on the lumenal surface of the graft.

Infrainguinal Bypass Grafting Using Lyophilized Saphenous Vein Allografts for Limb Salvage

Critical ischemia in patients with extensive femoropopliteal occlusive disease often ends in amputation in the absence of a suitable autologous vein for reconstruction. Cryopreserved vascular allografts have been used as an alternative conduit with poor results. Antigenicity and rejection are assumed to account for graft failure. Lyophilized vessels have demonstrated patency and structural integrity in the vascular system in our previous experimental studies. We report four patients that underwent femorodistal bypass grafting with lyophilized saphenous veins who lacked usable autologous vein for arterial reconstruction. Early graft thrombosis occurred in three patients who required major amputations. Duplex scans for graft surveillance did not reveal previous significant abnormalities. These cases demonstrate that the clinical use of lyophilized venous allografts for infrainguinal arterial reconstructions failed to yield satisfactory patency and limb salvage. Lyophilized veins therefore are not useful alternative conduits in patients with critical ischemia and no suitable autologous vein grafts.

Infrainguinal bypass grafting using lyophilized saphenous vein allografts for limb salvage

Critical ischemia in patients with extensive femoropopliteal occlusive disease often ends in amputation in the absence of a suitable autologous vein for reconstruction. Cryopreserved vascular allografts have been used as an alternative conduit with poor results. Antigenicity and rejection are assumed to account for graft failure. Lyophilized vessels have demonstrated patency and structural integrity in the vascular system in our previous experimental studies. We report four patients that underwent femorodistal bypass grafting with lyophilized saphenous veins who lacked usable autologous vein for arterial reconstruction. Early graft thrombosis occurred in three patients who required major amputations. Duplex scans for graft surveillance did not reveal previous significant abnormalities. These cases demonstrate that the clinical use of lyophilized venous allografts for infrainguinal arterial reconstructions failed to yield satisfactory patency and limb salvage. Lyophilized veins therefore are not useful alternative conduits in patients with critical ischemia and no suitable autologous vein grafts.

Clinical and Biological Relevance of Vein Cuff Anastomosis

Since a significant number of patients do not have suitable autologous saphenous vein for femorodistal bypass, the search for alternative graft material continues. The most commonly used prosthetic material is Polytetrafluoroethylene, however because of the poor patency of these grafts in the below knee position, a variety of techniques have been tried to improve their patency. A series of studies utilizing venous cuffs at the distal anastomosis have showed improved patency of PTFE grafts. We have reviewed the biological basis for graft failure and the literature for possible mechanical explanations.

Patency of Infrainguinal Polytetrafluoroethylene Bypass Grafts with Distal Interposition Vein Cuffs

Polytetrafluoroethylene (PTFE) prosthetic bypasses in the lower extremity have poor patency rates, particularly in limb salvage cases. Patency and limb salvage rates of PTFE bypasses supplemented by distal interposition vein cuffs were assessed in patients requiring revascularization for critical limb ischemia, in the absence of a suitable autologous saphenous vein. Between October 1993 and April 1996, 163 patients underwent 185 infrainguinal bypasses. Forty-three limbs in 42 patients (12 women, 30 men; mean age 67 years) did not have a suitable autologous saphenous vein (24%) and had femoropopliteal (20) and infrapopliteal (23) bypasses performed. Patients were examined prospectively at 3-month intervals during the first year and at 6-month intervals thereafter to determine graft patency and limb salvage. Postoperative anticoagulation with warfarin was used in 26 patients. Indications for operation included limb salvage in 41 extremities (21 rest pain/ulceration or gangrene, 20 rest pain alone), and disabling claudication in two. Patients were followed clinically for 2–30 months (mean 10 months). Cumulative 2-year life-table patencies for all grafts, femoropopliteal and infrapopliteal bypasses were 64%, 75% and 62%, respectively. Previous primary patencies at the authors' institution for PTFE bypasses without vein cuffs were 35%, 46% and 12% for the same categories. Cumulative life-table limb salvage for all PTFE/vein cuff bypasses in the present series was 76% compared with 37% in previous PTFE bypasses without vein cuffs. Adjunctive use of distal interposition vein cuffs improves prosthetic graft patency, while producing satisfactory limb salvage. Postoperative anticoagulation did not influence graft patency. PTFE/vein cuff for lower-extremity revascularization shows good 2-year patency and is an acceptable alternate conduit in patients with critical limb ischemia when autologous saphenous vein is absent.

Patency of infrainguinal polytetrafluoroethylene bypass grafts with distal interposition vein cuffs

Polytetrafluoroethylene (PTFE) prosthetic bypasses in the lower extremity have poor patency rates, particularly in limb salvage cases. Patency and limb salvage rates of PTFE bypasses supplemented by distal interposition vein cuffs were assessed in patients requiring revascularization for critical limb ischemia, in the absence of a suitable autologous saphenous vein. Between October 1993 and April 1996, 163 patients underwent 185 infrainguinal bypasses. Forty-three limbs in 42 patients (12 women, 30 men; mean age 67 years) did not have a suitable autologous saphenous vein (24%) and had femoropopliteal (20) and infrapopliteal (23) bypasses performed. Patients were examined prospectively at 3-month intervals during the first year and at 6-month intervals thereafter to determine graft patency and limb salvage. Postoperative anticoagulation with warfarin was used in 26 patients. Indications for operation included limb salvage in 41 extremities (21 rest pain/ulceration or gangrene, 20 rest pain alone), and disabling claudication in two. Patients were followed clinically for 2–30 months (mean 10 months). Cumulative 2-year life-table patencies for all grafts, femoropopliteal and infrapopliteal bypasses were 64%, 75% and 62%, respectively. Previous primary patencies at the authors' institution for PTFE bypasses without vein cuffs were 35%, 46% and 12% for the same categories. Cumulative life-table limb salvage for all PTFE/vein cuff bypasses in the present series was 76% compared with 37% in previous PTFE bypasses without vein cuffs. Adjunctive use of distal interposition vein cuffs improves prosthetic graft patency, while producing satisfactory limb salvage. Postoperative anticoagulation did not influence graft patency. PTFE/vein cuff for lower-extremity revascularization shows good 2-year patency and is an acceptable alternate conduit in patients with critical limb ischemia when autologous saphenous vein is absent.

Below-Knee Bypass Using Fresh Arterial Allografts for Limb Salvage: Early Results

The purpose of this study was to evaluate early results of below-knee bypass using fresh arterial allografts as arterial substitutes for limb salvage. From April 1991 to September 1993, we performed 28 below-knee bypass procedures using fresh arterial allografts in patients without a suitable autologous vein. Allografts were obtained by multiorgan harvesting from brain-dead subjects and preserved at 4 degrees C. Histologic examination of grafts was carried out. Secondary patency at 2 years calculated using the Kaplan-Meier method was 64% (confidence interval [CI] 45%-79%). No signs of graft deterioration or rejection were noted. These preliminary results are encouraging but long-term assessment is needed before expanding the range of application.

Lower Extremity Bypass for Critical Ischemia Using Synthetic Conduit and Adjuvant Vein Cuff

The use of an interposition cuff of vein placed at the distal anastomosis between synthetic bypass conduit and outflow vessel has been advocated to improve patency of lower extremity bypass grafts. Over a three-year period we have performed 43 such bypass procedures: to the above knee popliteal artery (n = 3); below knee popliteal (n = 13), and infrapopliteal arteries (n = 27). There were 20 females and 23 males having a mean age of 70 years (48-84 years). Fifteen patients were hypertensive, 15 were diabetic, and 25 had a history of tobacco use. All cases required limb salvage for rest pain (n = 25), gangrene (n = 10), or ulceration (n = 8) in the absence of suitable autologous vein. Nineteen operations followed a previous failed bypass. Patients were reviewed at six-month intervals. The operative mortality was 8% and two-year primary and secondary patency were 40% and 55%, respectively. Cumulative patency rates were better for first-time grafting procedures than for patients who had undergone previous attempts at limb salvage (60% versus 22%). Two-year limb salvage was 60%. During the same time period, two-year primary and secondary patency rates were 54% and 67%, respectively for autogenous vein. Although the numbers are small these results support the use of an adjuvant vein cuff when employing synthetic grafts. A prospective study of vein versus synthetic graft plus cuff should be undertaken.