Optimal conduit choice in the absence of single-segment great saphenous vein for below-knee popliteal bypass

Anticoagulation does not improve limb outcomes after lower extremity cryopreserved vein bypass

OBJECTIVE

Cryopreserved vein grafts serve as alternative conduits for infrainguinal bypass when autogenous vein is unavailable or inadequate. Anticoagulation has been advocated to improve outcomes, but published studies demonstrate conflicting results. We assessed the association of anticoagulation on outcomes after infrainguinal bypass with cryopreserved vein in patients with chronic limb-threatening ischemia.

METHODS

The Vascular Quality Initiative was queried (2003-2022) for infrainguinal bypass performed using cryopreserved vein graft for chronic limb-threatening ischemia. Baseline characteristics, procedural details, and outcomes between those discharged with or without anticoagulation were recorded. Univariable, Kaplan-Meier, and multivariable analyses were performed.

RESULTS

There were 2336 patients who underwent an infrainguinal bypass with cryopreserved vein conduit. The average age was 70.6 years and 63.5% were male. Bypass targets were femoral/popliteal (27.5%) and tibial (72.5%). Indication for intervention included rest pain (25.7%) and tissue loss (74.3%). Patients were discharged with aspirin (80.1%), a P2Y12 inhibitor (45.6%), and anticoagulation (47.3%). Patients discharged on postoperative anticoagulation more often were treated for rest pain (28.1% vs 23.5%), had a tibial bypass target (78.4% vs 67.2%), and less often underwent endarterectomy (27.8% vs 34.2%) (all P < .05). Kaplan-Meier analysis at 1 year demonstrated that postoperative anticoagulation had similar freedom from loss of primary patency/death (28.9% vs 34.3%), major amputation/death (62.3% vs 63.8%), and reintervention/major amputation/death (50.6% vs 53.8%) (all P > .05), but higher survival (85.1% vs 81.7%; P = .03). Multivariable analysis at 1 year demonstrated that postoperative anticoagulation had a similar likelihood for loss of primary patency/death (hazard ratio [HR], 0.95; 95% confidence interval [CI], 0.83.-1.09), major amputation/death (HR, 0.88; 95% CI, 0.74-1.05), and reintervention/major amputation/death (HR, 0.93; 95% CI, 0.79-1.08) (all P > .05), but a lower likelihood for death (HR, 0.59; 95% CI, 0.46-0.74; P < .001) compared with no anticoagulation. Postoperative aspirin was associated with a lower likelihood for amputation/death (HR, 0.74; 95% CI, 0.61-0.91; P = .003) and reintervention/major amputation/death (HR, 0.76; 95% CI, 0.64-0.9; P = .002). Postoperative P2Y12 inhibitor was associated with decreased likelihood for amputation/death (HR, 0.75; 95% CI, 0.63-0.9; P = .002) and reintervention/major amputation/death (HR, 0.78; 95% CI, 0.67-0.91; P = .001). Results were similar when analyzing patients who were not on anticoagulation preoperatively.

CONCLUSIONS

Postoperative anticoagulation after infrainguinal bypass using cryopreserved vein did not affect patency or limb salvage. Antiplatelet agents were associated with improved outcomes. Overall patency and limb salvage rates at 1 year were poor. When cryopreserved vein is used, surgeons should consider antiplatelet therapy for cryopreserved graft patency rather than anticoagulation.

Prosthetic conduits have worse outcomes compared with great saphenous vein conduits in femoropopliteal and infrapopliteal bypass in patients with chronic limb-threatening ischemia

OBJECTIVE

Single segment great saphenous vein (SSGSV) traditionally has been considered the gold standard conduit for infrainguinal bypass. There are data supporting similar outcomes with prosthetic femoral-popliteal bypass. Moreover, some investigators have advocated for prosthetic conduit for femoral tibial bypass when GSV is inadequate or unavailable. We sought to evaluate long-term outcomes of infrainguinal bypass based on conduit type for treating chronic limb-threatening ischemia (CLTI).

METHODS

Data from the Best Endovascular vs Best Surgical Therapy of Patients with CLTI multicenter, prospective, randomized controlled trial, comparing infrainguinal bypass with endovascular therapy in patients with CLTI, were evaluated. In this as-treated analysis, we compared outcomes of infrainguinal bypass using prosthetic, alternative autogenous vein (AAV), and cryopreserved vein (Cryo) with SSGSV bypass. Kaplan-Meier and multivariable analyses were performed to examine the associations of conduit type with major adverse limb events (MALE), reinterventions, above-ankle amputations, and all-cause death rates.

RESULTS

In total, 784 bypasses were analyzed (120 prosthetic, 33 AAV, 21 Cryo, AND 610 SSGSV). For prosthetic and SSGSV, the distribution was 357 femoropopliteal (93 prosthetic and 264 GSV) and 373 infrapopliteal (27 prosthetic and 346 GSV). The mean age for the overall cohort was 67.1 years; 27.4% were female, 29.9% were non-White, and 11.5% were of Hispanic ethnicity. Patients undergoing prosthetic bypass were older (69.2 years vs 66.7 years); more likely to have chronic obstructive pulmonary disease (22.5% vs 14.0%), prior coronary artery bypass grafting (88.9% vs 66.5%), and prior stroke (23.3% vs 14%); but less often were of Hispanic ethnicity (5.8% vs 12.6%) and had diabetes (59.2% vs 71.3%) (P < .05 for all). For femoropopliteal bypass, use of prosthetic conduit was associated with increased major reinterventions at 3 years overall (19.0% vs 11.5%; P = .06) and on risk-adjusted analysis (hazard ratio [HR], 2.13; 95% confidence interval [CI], 1.09-4.2; P = .028). No significant differences in MALE or death, above-ankle amputation, or death were observed. Outcomes were similar for bypasses to above-knee popliteal targets and below-knee popliteal targets. For infrapopliteal bypass, the use of a prosthetic conduit was associated with increased major reintervention (25.3% vs 10.3%; P = .005), death (68.6% vs 34.8%; P < .001), and MALE or death (90.0% vs 48.1%; P < .001) at 3 years. After risk adjustment, infrapopliteal bypass with prosthetic conduit was associated with higher major reintervention (HR, 4.14; 95% CI, 1.36-12.6; P = .012), above-ankle amputation (HR, 4.64; 95% CI, 1.59-13.5; P = .005), death (HR, 2.96; 95% CI, 1.4-6.2; P = .004), and MALE or death (HR, 3.59; 95% CI, 1.64-7.86; P = .001) compared with bypass with SSGSV. Overall, AAV had similar outcomes at 3 years as SSGSV; however, Cryo had significantly higher above-ankle amputation (50.0% vs 12.8%) (HR, 4.2; 95% CI, 1.68-10.5; P = .002), major reintervention (41.9% vs 10.7%) (HR, 3.12; 95% CI, 1.18-8.22; P = .02), and MALE/death (88.8% vs 37.8%) (HR, 2.96; 95% CI, 1.43-6.14; P = .004).

CONCLUSIONS

The use of a prosthetic conduit in infrainguinal bypass is associated with inferior outcomes compared with bypass using SSGSV, particularly for bypass to infrapopliteal targets. Cryo grafts were infrequent and also demonstrated inferior outcomes. SSGSV remains the preferred conduit of choice for infrainguinal bypass.

Spliced-Vein Conduit Offers Better Patency and Limb Salvage Than Prosthetic Graft for Femoral-Tibial Bypasses in Critical Limb-Threatening Ischemia

BACKGROUND

Single-segment great saphenous vein (ssGSV) is the gold standard conduit for femoral-tibial bypasses in patients with critical limb-threatening ischemia (CLTI). In the absence of a good single-segment saphenous vein, alternative options are prosthetic grafts or spliced-vein (SpV) conduits. Although SpV conduits may provide better long-term patency/limb salvage, prosthetic grafts are more often the chosen conduit due to shorter operative and presumably better immediate postoperative outcomes; nevertheless, there are little data supporting this practice. In this study, we compared 30-day outcomes between SpV and prosthetic conduits in CLTI bypass using a national registry.

METHODS

CLTI patients who underwent lower extremity bypass using SpV or prosthetic conduits only were selected from the National Surgical Quality Improvement Program targeted database. A 1:5 propensity score matching was conducted between SpV and prosthetic groups to address preoperative differences. Thirty-day outcomes, including primary patency, reintervention, major amputation, mortality, major morbidity, transfusion, and wound complications, were compared between the 2 groups.

RESULTS

There were 886 patients who underwent femoral-tibial bypass without ssGSV (104 SpV and 782 prosthetic grafts). All SpV patients were propensity score matched to 445 prosthetic patients. SpV exhibited significantly better 30-day primary patency than prosthetic (87.5% vs 74.38%, P = 0.004). SpV was associated with significantly longer operative time (346 min vs 222 min, P < 0.001) and higher transfusion (43.3% vs 27.87%, P = 0.003), but those did not translate into higher 30-day mortality or major systemic complications. There was no difference in wound complications or 30-day limb loss.

CONCLUSIONS

SpV conduit affords significantly better 30-day primary patency than prosthetic grafts without increased mortality and morbidities. Therefore, despite greater procedural complexity and longer operative time, SpV conduit should be considered when available. Future prospective studies are needed to investigate the long-term outcomes of these 2 conduits.

Comparative outcomes of arterial bypass using the human acellular vessel and great saphenous vein in patients with chronic limb ischemia

OBJECTIVE

The Human Acellular Vessel (HAV) is a novel, off-the-shelf biologic conduit being evaluated for arterial reconstructions. Regulatory studies in peripheral arterial disease (PAD) to date have consisted of single-arm cohorts with no comparator groups to contrast performance against established standards. This study aimed to compare outcomes of the HAV with autologous great saphenous vein (GSV) in patients with advanced PAD undergoing infrageniculate bypass.

METHODS

Patients with advanced PAD and no autologous conduit who underwent bypass with the 6-mm diameter HAV (Group 1; n = 34) (March 2021-February 2024) were compared with a multicenter historical cohort who had bypass with single-segment GSV (group 2; n = 88) (January 2017-December 2022). The HAV was used under an Investigational New Drug protocol issued by the Food and Drug Administration (FDA) under the agency's Expanded Access Program.

RESULTS

Demographics were comparable between groups (mean age 69 ± 10 years; 71% male). Group 1 had higher rates of tobacco use (37 pack-years vs 28 pack-years; P = .059), coronary artery disease (71% vs 43%; P = .007), and prior coronary artery bypass grafting (38% vs 14%; P = .003). Group 1 had more patients classified as wound, ischemia, and foot infection clinical stage 4 (56% vs 33%; P = .018) and with previous index leg revascularizations (97% vs 53%; P < .001). Both groups had a similar number of patients with chronic limb-threatening ischemia (Rutherford class 4-6) (88% vs 86%; P = .693) and Global Anatomic Staging System stage III (91% vs 96%; P = .346). Group 1 required a composite conduit (two HAV sewn together) in 85% of bypasses. The tibial vessels were the target in 79% of group 1 and 100% of group 2 (P < .001). Group 1 had a lower mean operative time (364 minutes vs 464 minutes; P < .001). At a median of 12 months, major amputation-free survival (73% vs 81%; P = .55) and overall survival (84% vs 88%; P = .20) were comparable. Group 1 had lower rates of primary patency (36% vs 50%; P = .044), primary-assisted patency (45% vs 72%; P = .002), and secondary patency (64% vs 72%; P = .003) compared with group 2.

CONCLUSIONS

Implanted under Food and Drug Administration Expanded Access provisions, the HAV was more likely to be used in redo operations and cases with more advanced limb ischemia than GSV. Despite modest primary patency, the HAV demonstrated resilience in a complex cohort with no autologous conduit options, achieving good secondary patency and providing major amputation-free survival comparable with GSV at 12 months.

Contemporary outcomes for arterial reconstruction with non-saphenous vein cryo-preserved conduits

OBJECTIVE

Cryopreserved (CP) products are utilized during challenging cases when autogenous or prosthetic conduit use is not feasible. Despite decades of experience with cadaveric greater saphenous vein (GSV), there is limited available data regarding the outcomes and patency of other CP products, specifically arterial and deep venous grafts. This study was designed to evaluate outcomes of non-GSV CP conduits in patients undergoing urgent, emergent, and elective arterial reconstruction at our institution. We hypothesized that non-GSV CP allografts have adequate patency and outcomes and are therefore a feasible alternative to GSV in settings where autologous graft is unavailable or prosthetic grafts are contraindicated.

METHODS

This study was approved by the Institutional Review Board at our institution. We retrospectively reviewed charts of patients undergoing arterial reconstructions using CP conduits from 2010 to 2022. Data collected included demographics, comorbidities, smoking status, indications for surgery, indication for CP conduit use, anatomic reconstruction, urgency of procedure, and blood loss. Time-to-event outcomes included primary and secondary graft patency rates, follow-up amputations, and mortality; other complications included follow-up infection/reinfection and 30-day complications, including return to the operating room and perioperative mortality. Time-to-event analyses were evaluated using product-limit survival estimates.

RESULTS

Of 96 identified patients receiving CP conduits, 56 patients received non-GSV conduits for 66 arterial reconstructions. The most common type of non-GSV CP product used was femoral artery (31 patients), followed by aorto-iliac artery (22 patients), and femoral vein (19 patients), with some patients receiving more than one reconstruction or CP product. Patients were mostly male (75%), with a mean age of 63.1 years and a mean body mass index of 26.7 kg/m2. Indications for CP conduit use included infection in 53 patients, hostile environment in 36 patients, contaminated field in 30 patients, tissue coverage concerns in 30 patients, inadequate conduit in nine patients, and patient preference in one patient. Notably, multiple patients had more than one indication. Most surgeries (95%) were performed in urgent or emergent settings. Supra-inguinal reconstructions were most common (53%), followed by extra-anatomic bypasses (47%). Thirty-day mortality occurred in 10 patients (19%). Fifteen patients (27%) required return to the operating room for indications related to the vascular reconstructions, with 10 (18%) cases being unplanned and five (9%) cases planned/staged. Overall survival at 6, 12, and 24 months was 80%, 68%, and 59%, respectively. Primary patency at 6, 12, and 24 months was 86%, 70%, and 62%, respectively. Amputation freedom at 6 months, 12 months, and 24 months was 98%, 95%, and 86%, respectively for non-traumatic indications.

CONCLUSIONS

Non-GSV CP products may be used in complex arterial reconstructions when autogenous or prosthetic options are not feasible or available.

Predictors of amputation-free survival and wound healing after infrainguinal bypass with alternative conduits

OBJECTIVE

Inadequate vein quality or prior harvest precludes use of autologous single segment greater saphenous vein (ssGSV) in many patients with chronic limb-threatening ischemia (CLTI). Predictors of patient outcome after infrainguinal bypass with alternative (non-ssGSV) conduits are not well-understood. We explored whether limb presentation, bypass target, and conduit type were associated with amputation-free survival (AFS) after infrainguinal bypass using alternative conduits.

METHODS

A single-center retrospective study (2013-2020) was conducted of 139 infrainguinal bypasses performed for CLTI with cryopreserved ssGSV (cryovein) (n = 71), polytetrafluoroethylene (PTFE) (n = 23), or arm/spliced vein grafts (n = 45). Characteristics, Wound, Ischemia, and foot Infection (WIfI) stage, and outcomes were recorded. Multivariable Cox proportional hazards and classification and regression tree analysis modeled predictors of AFS.

RESULTS

Within 139 cases, the mean age was 71 years, 59% of patients were male, and 51% of cases were nonelective. More patients undergoing bypass with cryovein were WIfI stage 4 (41%) compared with PTFE (13%) or arm/spliced vein (27%) (P = .04). Across groups, AFS at 2 years was 78% for spliced/arm, 79% for PTFE, and 53% for cryovein (adjusted hazard ratio for cryovein, 2.5; P = .02). Among cases using cryovein, classification and regression tree analysis showed that WIfI stage 3 or 4, age >70 years, and prior failed bypass were predictive of the lowest AFS at 2 years of 36% vs AFS of 58% to 76% among subgroups with less than two of these factors. Although secondary patency at 2 years was worse in the cryovein group (26% vs 68% and 89% in arm/spliced and PTFE groups; P < .01), in patients with tissue loss there was no statistically significant difference in wound healing in the cryovein group (72%) compared with other bypass types (72% vs 87%, respectively; P = .12).

CONCLUSIONS

In patients with CLTI lacking suitable ssGSV, bypass with autogenous arm/spliced vein or PTFE has superior AFS compared with cryovein, although data were limited for PTFE conduits for distal targets. Despite poor patency with cryovein, wound healing is achieved in a majority of cases, although it should be used with caution in older patients with high WIfI stage and prior failed bypass, given the low rates of AFS.

Development of heparinized and hepatocyte growth factor-coated acellular scaffolds using porcine carotid arteries

Tissue-engineered blood vessel substitutes have been developed due to the lack of suitable small-diameter vascular grafts. Xenogeneic extracellular matrix (ECM) scaffolds have the potential to provide an ideal source for off-the-shelf vascular grafts. In this study, porcine carotid arteries were used to develop ECM scaffolds by decellularization and coating with heparin and hepatocyte growth factor (HGF). After decellularization, cellular and nucleic materials were successfully removed with preservation of the main compositions (collagen, elastin, and basement membrane) of the native ECM. The ultimate tensile strength, suture strength, and burst pressure were significantly increased after cross-linking. Pore size distribution analysis revealed a porous structure within ECM scaffolds with a high distribution of pores larger than 10 μm. Heparinized scaffolds exhibited sustained release of heparin in vitro and showed potent anticoagulant activity by prolonging activated partial thromboplastin time. The scaffolds showed an enhanced HGF binding capacity as well as a constant release of HGF as a result of heparin modification. When implanted subcutaneously in rats, the modified scaffolds revealed good biocompatibility with enzyme degradation resistance, mitigated immune response, and anti-calcification. In conclusion, heparinized and HGF-coated acellular porcine carotid arteries may be a promising biological scaffold for tissue-engineered vascular grafts.

Evaluation of tissue-engineered human acellular vessels as a Blalock-Taussig-Thomas shunt in a juvenile primate model

Objectives

Palliative treatment of cyanotic congenital heart disease (CCHD) uses systemic-to-pulmonary conduits, often a modified Blalock-Taussig-Thomas shunt (mBTTs). Expanded polytetrafluoroethylene (ePTFE) mBTTs have associated risks for thrombosis and infection. The Human Acellular Vessel (HAV) (Humacyte, Inc) is a decellularized tissue-engineered blood vessel currently in clinical trials in adults for vascular trauma, peripheral artery disease, and end-stage renal disease requiring hemodialysis. In addition to restoring blood flow, the engineered HAV demonstrates the capacity for host cellular remodeling into native-like vasculature. Here we report preclinical evaluation of a small-diameter (3.5 mm) HAV as a mBTTs in a non-human primate model.

Methods

We implanted 3.5 mm HAVs as right subclavian artery to pulmonary artery mBTTs in non-immunosuppressed juvenile rhesus macaques (n = 5). HAV patency, structure, and blood flow were assessed by postoperative imaging from 1 week to 6 months. Histology of HAVs and surrounding tissues was performed.

Results

Surgical procedures were well tolerated, with satisfactory anastomoses, showing feasibility of using the 3.5 mm HAV as a mBTTs. All macaques had some immunological reactivity to the human extracellular matrix, as expected in this xenogeneic model. HAV mBTTs remained patent for up to 6 months in animals, exhibiting mild immunoreactivity. Two macaques displaying more severe immunoreactivity to the human HAV material developed midgraft dilatation without bleeding or rupture. HAV repopulation by host cells expressing smooth muscle and endothelial markers was observed in all animals.

Conclusions

These findings may support use of 3.5 mm HAVs as mBTTs in CCHD and potentially other pediatric vascular indications.

Comparison of arterial and venous allograft bypass in chronic limb-threatening ischemia

INTRODUCTION

Femoro-popliteal bypass with autologous vascular graft is a key revascularization method in chronic limb-threatening ischemia (CLTI). However, the lack of suitable autologous conduit may occur in 15-45% of the patients, necessitating the implantation of prosthetic or allogen grafts. Only little data is available on the outcome of allograft use in CLTI.

AIMS

Our objective were to evaluate the long term results of infrainguinal allograft bypass surgery in patients with chronic limb-threatening ischemia (CLTI) and compare the results of arterial and venous allografts.

METHODS

Single center, retrospective study analysing the outcomes of infrainguinal allograft bypass surgery in patients with CLTI between January 2007 and December 2017.

RESULTS

During a 11-year period, 134 infrainguinal allograft bypasses were performed for CLTI [91 males (67.9%)]. Great saphenous vein (GSV) was implanted in 100 cases, superficial femoral artery (SFA) was implanted in 34 cases. Early postoperative complications appeared in 16.4% of cases and perioperative mortality (<30 days) was 1.4%. Primary patency at one, three and five years was 59%, 44% and 41%, respectively, while secondary patency was 60%, 45% and 41%, respectively. Primary patency of the SFA allografts was significantly higher than GSV allografts (1 year: SFA: 84% vs. GSV: 51% p = 0,001; 3 years: SFA: 76% vs. GSV: 32% p = 0,001; 5 years: SFA: 71% vs. GSV: 30% p = 0.001). Both primary and secondary patency of SFA allograft implanted in below-knee position were significantly higher than GSV bypasses (p = 0.0006; p = 0.0005, respectively). Limb salvage at one, three and five years following surgery was 74%, 64% and 62%, respectively. Long-term survival was 53% at 5 years.

CONCLUSION

Allograft implantation is a suitable method for limb salvage in CLTI. The patency of arterial allograft is better than venous allograft patency, especially in below-knee position during infrainguinal allograft bypass surgery.

Alternative autologous and biologic conduits have worse outcomes than prosthetic grafts for infrainguinal bypass in patients with chronic limb-threatening ischemia

OBJECTIVE

Single segment great saphenous vein (GSV) is the preferred conduit in infrainguinal bypass. Alternative autologous conduits (AAC) and nonautologous biologic conduits (NABC) are thought to be a better alternative to traditional prosthetic conduits (PC) in the absence of GSV. In this study we analyzed the outcomes of these alternative conduits in lower extremity bypasses (LEB) in patients with chronic limb-threatening ischemia.

METHODS

The Vascular Quality Initiative LEB database from 2003 to 2020 was queried for this study, to identify LEB in patients with chronic limb-threatening ischemia. Primary outcomes were graft patency, major adverse limb events (MALE), and MALE-free survival at 1 year. Standard statistical methods were used as appropriate.

RESULTS

We identified 22,671 LEB procedures (12,810 GSV, 6002 PC, 1907 AAC, and 1952 NABC). Compared with the GSV group, the other conduit patients were significantly older, had more comorbidities, had an increased rate of prior lower extremity interventions, had a higher rate of infrageniculate bypass targets, and were less ambulatory at baseline. The PC, AAC, and NABC groups had significantly higher rates of postoperative morbidity compared with the GSV group. The PC group had a higher 30-day mortality compared with the GSV, AAC, and NABC groups (3% PC vs 2% GSV, 2% AAC, 2% NABC; P = .049). Both PC and NABC had higher 1-year mortality compared with GSV and AAC (13% PC and 13% NABC vs 10% GSV, 10% AAC; P = .02). In an adjusted Cox regression model (stratified by infrageniculate target and adjusted for age, comorbidities, and prior vascular interventions) PC was not significantly different from GSV, but AAC (hazard ratio [HR], 1.41; 95% confidence interval [CI], 1.19-1.67; P < .001) and NABC (HR, 1.9; 95% CI, 1.61-2.25; P < .001) were associated with an increased risk of loss of primary patency. A similar association with MALE was observed: both AAC (HR, 1.35; 95% CI, 1.15-1.58; P < .001) and NABC (HR, 1.8; 95% CI, 1.53-2.11; P < .001) were associated with an increased risk of MALE compared with GSV; PC was not significantly different from GSV.

CONCLUSIONS

In the absence of GSV, alternative conduits (autologous or nonautologous biologic) do not confer a benefit with regard to graft patency or MALE compared with PCs. Increased operating time or costs associated with the use of these conduits is not justified based on this study.

Cryopreservation moderates the thrombogenicity of arterial allografts during storage

INTRODUCTION

Management of vascular infections represents a major challenge in vascular surgery. The use of cryopreserved vascular allografts could be a feasible therapeutic option, but the optimal conditions for their production and use are not precisely defined.

AIMS

To evaluate the effects of cryopreservation and the duration of storage on the thrombogenicity of femoral artery allografts.

METHODS

In our prospective study, eleven multi-organ-donation-harvested human femoral arteries were examined at five time points during storage at -80°C: before cryopreservation as a fresh native sample and immediately, one, twelve and twenty-four weeks after the cryopreservation. Cross-sections of allografts were perfused with heparin-anticoagulated blood at shear-rates relevant to medium-sized arteries. The deposited platelets and fibrin were immunostained. The thrombogenicity of the intima, media and adventitia layers of the artery grafts was assessed quantitatively from the relative area covered by fibrin- and platelet-related fluorescent signal in the confocal micrographs.

RESULTS

Regression analysis of the fibrin and platelet coverage in the course of the 24-week storage excluded the possibility for increase in the graft thrombogenicity in the course of time and supported the hypothesis for a descending trend in fibrin generation and platelet deposition on the arterial wall. The fibrin deposition in the cryopreserved samples did not exceed the level detected in any of the three layers of the native graft. However, an early (up to week 12) shift above the native sample level was observed in the platelet adhesion to the media.

CONCLUSIONS

The hemostatic potential of cryopreserved arterial allografts was retained, whereas their thrombogenic potential declined during the 6-month storage. The only transient prothrombotic change was observed in the media layer, where the platelet deposition exceeded that of the fresh native grafts in the initial twelve weeks after cryopreservation, suggesting a potential clinical benefit from antiplatelet therapy in this time-window.

In vivo recellularization of xenogeneic vascular grafts decellularized with high hydrostatic pressure method in a porcine carotid arterial interpose model

Autologous vascular grafts are widely used in revascularization surgeries for small caliber targets. However, the availability of autologous conduits might be limited due to prior surgeries or the quality of vessels. Xenogeneic decellularized vascular grafts from animals can potentially be a substitute of autologous vascular grafts. Decellularization with high hydrostatic pressure (HHP) is reported to highly preserve extracellular matrix (ECM), creating feasible conditions for recellularization and vascular remodeling after implantation. In the present study, we conducted xenogeneic implantation of HHP-decellularized bovine vascular grafts from dorsalis pedis arteries to porcine carotid arteries and posteriorly evaluated graft patency, ECM preservation and recellularization. Avoiding damage of the luminal surface of the grafts from drying significantly during the surgical procedure increased the graft patency at 4 weeks after implantation (P = 0.0079). After the technical improvement, all grafts (N = 5) were patent with mild stenosis due to intimal hyperplasia at 4 weeks after implantation. Neither aneurysmal change nor massive thrombosis was observed, even without administration of anticoagulants nor anti-platelet agents. Elastica van Gieson and Sirius-red stainings revealed fair preservation of ECM proteins including elastin and collagen after implantation. The luminal surface of the grafts were thoroughly covered with von Willebrand factor-positive endothelium. Scanning electron microscopy of the luminal surface of implanted grafts exhibited a cobblestone-like endothelial cell layer which is similar to native vascular endothelium. Recellularization of the tunica media with alpha-smooth muscle actin-positive smooth muscle cells was partly observed. Thus, we confirmed that HHP-decellularized grafts are feasible for xenogeneic implantation accompanied by recellularization by recipient cells.

The Upper-Arm Basilic-Cephalic Loop: A Valueable Alternative for Below-Knee Arterial Reconstruction

INTRODUCTION

Despite advances of endovascular interventions, bypass surgery remains the gold standard for treatment of long and complex arterial occlusions in the lower limb. Autologous vein is regarded superior to other options. As the graft of first choice, the great saphenous vein (GSV) is often not available due to previous bypass, stripping or poor quality. Other options like arm veins (AV) are important alternatives. As forearm portions of AVs are often unusable, a graft created from the upper arm basilic and cephalic veins provides a valuable alternative.

PATIENTS AND METHODS

We analyzed consecutive patients treated at an academic tertiary referral center between 01/1998 and 07/2018 using arm veins as the main peripheral bypass graft. Study endpoints were primary patency, secondary patency, limb salvage and survival.

RESULTS

In the observed time period 2702 bypass procedures were performed at our institution for below-knee arterial reconstructions. Vein grafts used included the ipsilateral GSV (iGSV; n = 1937/71.7%), contralateral GSV (cGSV; 192/7.1%), small saphenous vein (SSV; 133/4.9%), prosthetic conduits (61/2.3%) and different configurations of AV (379/14%). In the majority of patients receiving AV grafts a complete continuous cephalic or basilic vein (CAV) was used (n = 292/77%). If it was not possible to use major parts of these 2 veins, either spliced arm vein grafts (SAV) (42/11%) or an upper arm basilic-cephalic loop graft (45/12%) were used. Median follow-up was 27 (interquartile range: 8-50) months. After 3 years secondary patency (CAV: 85%; SAV: 62%; loop: 66%; p = 0.125) and limb salvage rates (CAV: 79%, SAV: 68%; loop: 79%; p = 0.346) were similar between the 3 bypass options.

CONCLUSION

The encouraging results of alternative AV configurations highlight their value in case the basilic or cephalic veins are not useable in continuity. Especially for infragenual redo-bypass procedures, these techniques should be considered to offer patients durable revascularization options.

Comparison of Cryopreserved Arterial Allografts Versus Heparin-bonded Vascular Grafts in Infragenicular Bypass for Chronic Limb Threatening Ischemia

BACKGROUND

The purpose of this study was to compare cryopreserved arterial allograft (CAA) to heparin-bonded prosthesis (HBP) in infragenicular bypasses for patients with chronic limb-threatening ischemia (CLTI).

METHODS

This retrospective study took place in 2 university hospitals and included 41 consecutive patients treated for CLTI. In the absence of a suitable saphenous vein, an infragenicular bypass was performed using either CAA (24 cases) or HBP (17 cases). Kaplan-Meyer analysis compared primary and secondary patency and amputation-free survival rates. Binomial logistic regression analyzed risk factors for major amputation and thrombosis.

RESULTS

The mean followup was 18.5 months (±14.3) in the CAA group, 17.6 (±6.1) in the HBP group. In the CAA group, primary and secondary patency rates at 12 months were 52% (±10.6) and 61% (±10.3), compared to 88% (±7.8) and 94% (±5.7) in the HBP group, respectively. The difference in patency rates was not statistically different (P = 0.27 and P = 0.28, respectively). The statistically significant factors of graft thrombosis were, a stage 4 from the WIfI classification (Wound Ischemia foot Infection) with a 6 times higher risk (P = 0.04), and a distal anastomosis on a leg artery with a 9 times higher risk of thrombosis (P = 0.03). Amputation-free survival rates at 18 months were similar between the groups (CCA: 75% (±9) versus HBP: 94% (±6), P = 0.11). Patients classified as WIfI stage 4 had 13 times higher odds to undergo major amputation than patients with WIfI stage 2 or 3 (95% CI, 1.16-160.93; P = 0.04). The intervention was longer in the CCA group of 74 min (278 min ± 86) compared to the HBP group (203 min ± 69). This difference was statistically significant (95% CI, 17.86-132.98), t(35) = 2.671, P = 0.01.

CONCLUSIONS

CCA is not superior to HBP in infragenicular bypasses for CLTI, and may not be worth the extra cost and the longer operative duration.

Infrainguinal bypass surgery outcomes are worse in hemodialysis patients compared with patients with renal transplants

OBJECTIVE

Studies of infrainguinal bypass surgery (IBS) in patients with end-stage renal disease have focused on hemodialysis (HD) patients. Little is known of the applicability of their outcomes to patients with renal transplants (RTs). In this study, we sought to compare perioperative and long-term outcomes of IBS in a large population-based cohort of HD and RT patients.

METHODS

A retrospective review of all HD and RT patients who underwent IBS between January 2007 and December 2011 in the U.S. Renal Data System was performed. Univariable, Kaplan-Meier, multivariable logistic, and Cox regression analyses were employed to evaluate 30-day postoperative (graft failure, limb loss, conduit infection, death) and long-term (primary patency [PP], primary assisted patency [PAP], secondary patency [SP], limb salvage, mortality) outcomes.

RESULTS

There were 10,787 IBSs performed in 9739 (90%) HD patients and 1048 (10%) RT patients who presented predominantly with critical limb ischemia (72%). Bypass configurations were femoral-popliteal (48%), femoral-tibial (34%), and popliteal-tibial (18%). Comparing HD vs RT patients, PP, PAP, and SP were 18% vs 33%, 23% vs 38%, and 30% vs 48%, respectively, at 5 years among autogenous conduit recipients (all P < .001) and 20% vs 28% (P = .02), 23% vs 31% (P = .02), and 33% vs 53% (P < .001) among prosthetic conduit recipients. Limb salvage and patient survival were 39% vs 56% and 19% vs 48%, respectively, at 5 years (all P < .001). Risk-adjusted analyses demonstrated higher PP (adjusted hazard ratio [aHR], 1.32; 95% confidence interval [CI], 1.20-1.45; P < .001), PAP (aHR, 1.32; 95% CI, 1.19-1.45; P < .001), SP (aHR, 1.47; 95% CI, 1.31-1.65; P < .001), limb salvage (aHR, 1.48; 95% CI, 1.30-1.67; P < .001), and patient survival (aHR, 2.42; 95% CI, 2.17-2.71; P < .001) for RT compared with HD patients.

CONCLUSIONS

The HD-dependent state is associated with elevated bypass and patient-level risks after IBS compared with patients with RTs. These results show that the benefits of renal transplantation likely extend to infrainguinal bypass-specific outcomes. The estimates of risk reported herein should inform the patient's and provider's expectations at the point of care.

Long-Term Results of Femorotibial Polytetrafluoroethylene Bypass with a Distal Vein Cuff for Critical Limb Ischemia

Objective: Although autologous veins are the first-choice conduit for femorotibial artery bypass, if there are no appropriate autologous veins, we perform femorotibial artery bypass using polytetrafluoroethylene (PTFE) with a distal vein cuff for patients with critical limb ischemia (CLI). This study examined the long-term outcomes of femorotibial artery bypass using PTFE with a Miller's cuff. Materials and Methods: Using prospectively collected data for 444 distal bypasses, a retrospective analysis was conducted for 32 femorotibial PTFE bypasses with a Miller's cuff (PTFE-Miller's cuff) performed for patients with CLI from April 1994 to December 2016. Results: Primary and secondary patency rates of PTFE-Miller's cuff at 3 years were 35.8% and 51.2%, respectively. Limb salvage rate of PTFE-Miller's cuff at 3 years was 71.0%. Conclusion: Although the patency rate was low and failed to yield satisfactory results, the limb salvage rate remained relatively high. Femorotibial PTFE bypass with a Miller's cuff was a useful technique of limb salvage for patients with CLI in whom an appropriate autologous vein could not be used.

Current Status of Arterial Revascularization for the Treatment of Critical Limb Ischemia in Infrainguinal Atherosclerotic Disease

Critical limb ischemia (CLI) is the most severe form of peripheral arterial disease (PAD) that may result in limb loss and even death; thus, the fast and proper treatment should be employed as earlier as possible to prevent these catastrophic consequences. Arterial revascularization is almost always an indispensable treatment option for CLI. Although both endovascular and surgical revascularization procedures have an important role, nowadays, the hybrid revascularization as a combination of these revascularization procedures has also gained increasing popularity in the treatment of patients with CLI. This review provides an update on the arterial revascularization strategies for the treatment of CLI.

National Utilization and Outcomes of Redo Lower Extremity Bypass versus Endovascular Intervention after a Previous Failed Bypass

BACKGROUND

Redo lower extremity bypass (LEB) and infrainguinal endovascular intervention (IEI) are options to treat critical limb ischemia after a failed prior LEB, but the utilization and outcomes of each are poorly described. The purpose of this study was to compare 30-day major adverse limb events (MALEs) and major adverse cardiovascular events (MACEs) after LEB and IEI in patients with a failed prior ipsilateral LEB and determine risk factors for each composite outcome.

METHODS

Patients with prior failed ipsilateral LEB who underwent LEB or IEI involving the same arterial segment for critical limb ischemia were identified in the National Surgical Quality Improvement Program (NSQIP) Vascular Targeted File (2011-2014). LEB with single-segment saphenous vein was compared to LEB with alternative conduit (prosthetic/spliced vein/composite) and IEI. Primary outcomes were MALE (untreated loss of patency, reintervention, or amputation) and MACE (stroke, myocardial infarction, or death). Multivariate analysis was utilized to identify independent predictors of MALE and MACE.

RESULTS

Among 8,066 revascularizations performed for critical limb ischemia (CLI), 1,606 (461 [28.7%] IEI, 518 [32.3%] LEB saphenous, and 627 [39.0%] LEB alternative) were performed after failed ipsilateral LEB involving the same arterial segment. LEB with saphenous had lower MALE than LEB with alternate conduit and IEI (15.8% IEI, 10.8% saphenous, and 15.5% alternative, P = 0.03). Higher MALE was driven by higher 30-day amputation in IEI (7.8% IEI, 3.7% saphenous, and 5.3% alternative, P = 0.02). Independent predictors of MALE include transfer status (odds ratio [OR] = 1.7, P = 0.01), tobacco use (OR = 1.5, P = 0.02), infrageniculate revascularization (OR = 1.6, P = 0.004), and saphenous conduit (OR = 0.5, P = 0.002). MACE was also different between groups (3.9% IEI, 7% saphenous, and 5.6% alternative, P = 0.049), with no difference in 30-day mortality (P = 0.53). Independent predictors of MACE included congestive heart failure (OR = 3.0, P = 0.01) and dialysis dependence (OR = 2.5, P = 0.02).

CONCLUSIONS

In this large national sample representing routine vascular care of patients with CLI after failed ipsilateral LEB of the same arterial segment, IEI is common and represents 30% of revascularizations in this data set. Redo LEB with saphenous is associated with superior limb-related outcomes, but IEI offers an acceptable potential alternative to bypass in patients who would require alternative conduit. Finally, perioperative care is critical as we demonstrate that patient comorbidities, not the method of revascularization, predicted MACE.

Long-term outcomes after autogenous versus synthetic lower extremity bypass in patients on hemodialysis

BACKGROUND

Hemodialysis dependence confers unique physiologic conditions. Prior reports of outcomes after infrainguinal open bypass operations in patients on hemodialysis have been based on relatively small sample institutional series. In this study, we evaluate long-term outcomes after open bypass operations in a large contemporary population-based cohort of hemodialysis patients. We studied all hemodialysis patients who underwent infrainguinal open operation using autogenous versus prosthetic conduits in the United States Renal Data System between January 2007 and December 2011.

METHODS

Univariate methods (χ², analysis of variance) were used to compare the characteristics of the patient and type of bypass. Kaplan-Meier, univariate and multivariate logistic, and Cox regression analyses were used to evaluate 30-day postoperative outcomes as well as patency, limb salvage, and mortality in the long term.

RESULTS

There were 9,739 (autogenous: 59%, prosthetic: 49%) infrainguinal open bypass operations performed in this cohort. Of these, 4,717 (48%) were femoral-popliteal, 3,321 (34%) were femoral-tibial, and 1,701 (18%) were popliteal-tibial bypasses. Bypass operations were performed most commonly for critical limb ischemia (72%). Primary patency was 18% for both types of conduits at 5 years (P = .16). Comparing autogenous versus prosthetic conduits, primary-assisted patency was 23% vs 20% at 5 years (P = .98), while secondary patency was 30% for both conduits at 5 years (P = .05). Limb salvage was 35% vs 41% at 5 years (P < .001). Multivariable analyses demonstrated greater patency (adjusted hazard ratio [aHR]: 1.16; 95% confidence interval, 1.05-1.28; P = .003) and limb salvage (aHR: 1.12; 95% confidence interval, 1.01-1.24; P = .03) for autogenous compared to prosthetic bypasses. The advantage conferred by autogenous conduits was most clinically relevant for femoral-tibial (aHR: 1.34; 95% confidence interval, 1.17-1.55; P < .001) and popliteal-tibial (aHR: 1.55; 95% confidence interval, 1.09-2.21; P = .014) configurations.

CONCLUSION

This large study evaluated the long-term outcomes of open bypass operations in patients on hemodialysis. The data confirm the long-term benefits of autogenous conduits compared with prosthetic conduits in this high-risk population of patients, especially for the treatment of distal lesions. Individual patient life expectancy, availability of adequate autogenous conduit options, indication for operation, level of disease, as well as potential need for future options for additional access for dialysis should be taken into consideration when deciding to construct an open bypass in a hemodialysis patient.

Results of Infrainguinal Bypass with a Composite Graft Combining Polytetrafluoroethylene and Vein Graft in Absence of Appropriate Saphenous Vein Graft

Purpose

Use of a composite graft combining a polytetrafluoroethylene graft with an autogenous vein is an option for limb salvage in the absence of an adequate single segment vein graft. We aimed to investigate the results of infrainguinal bypass with a composite graft.

Materials and Methods

We retrospectively reviewed 11 infrainguinal arterial bypasses on 11 limbs which underwent surgery from March 2012 to November 2016.

Results

Critical limb ischemia was common (63.6%) indication of bypass surgery and most (90.9%) of the patients had history of failed previous treatment including endovascular treatment (36.4%) and bypass surgery (72.7%). At the 2 years after graft implantations, primary patency and amputation-free survival of below-knee bypasses using composite graft were 73% and 76%, respectively.

Conclusion

Infrainguinal arterial bypasses with composite graft had an acceptable patency. In patients without other alternative conduits for revascularization, bypass with a composite graft can be an option.

Alternative conduit for infrageniculate bypass in patients with critical limb ischemia

BACKGROUND

Autologous great saphenous vein (GSV) has always been considered the gold standard conduit for infrainguinal revascularization. When GSV is inadequate or unavailable, alternative conduits have been used. In this study, we compared modern outcomes of different conduit types used in lower extremity bypass (LEB) for patients with critical limb ischemia (CLI).

METHODS

The Vascular Study Group of New England database (2003-2014) was queried for patients who underwent infrageniculate bypass originating from the femoral arteries. Conduit types were categorized as single-segment GSV, alternative autologous conduit (AAC), and nonautologous conduit (NAC). Primary outcomes were 1-year freedom from major adverse limb event (MALE), MALE-free survival, and primary graft patency. Multivariable Cox regression was used to adjust for demographics and comorbidities.

RESULTS

LEB was performed in 2148 patients, of which 1125 were to below-knee popliteal (BK-Pop) and 1023 to infrapopliteal artery (IPA) targets. The baseline characteristics differed among the conduit groups: Patients in the GSV group were younger and had fewer comorbidities than in the AAC groups. Patients undergoing BK-Pop bypass with NAC had higher rates of postoperative myocardial infarction (7.1%) and postoperative (5.8%) and 1-year death (40.8%) than in those with GSV (3.1%, 2%, and 31.7%, respectively) and AAC (0%, 0%, and 25%, respectively). In multivariable analysis, conduit type did not make a difference in 1-year MALE, MALE-free survival, or primary graft patency for BK-Pop bypasses. For IPA bypasses, NAC use was associated with higher rates of postoperative (6.4%) and in-hospital death (4.5%) compared with GSV (2.5% and 1.4%, respectively) and AAC (2.9% and 1.9%, respectively). In adjusted analysis, NAC was associated with higher risk of MALE (hazard ratio [HR], 1.50; 95% confidence interval [CI], 1.03-2.20; P = .036) and primary patency loss (HR, 1.3; 95% CI, 0.91-1.89), and lower MALE-free survival (HR, 1.47; 95% CI, 1.03-2.09; P = .035) compared with GSV. There was no difference between the NAC and AAC groups.

CONCLUSIONS

Conduit type does not affect outcomes in BK-Pop bypass. In the absence of single-segment GSV, the use of AAC for IPA bypass does not appear to confer any additional benefit of MALE, MALE-free survival, or graft patency compared with prosthetic grafts at 1-year follow-up.

Cryopreserved saphenous vein as a last-ditch conduit for limb salvage

OBJECTIVE

In patients lacking autogenous vein suitable for infrainguinal bypass, cryopreserved saphenous vein (CSV) allograft (CryoLife, Inc, Kennesaw, Ga) may be an acceptable alternative. The purpose of this study was to examine outcomes of CSV conduit for infrainguinal revascularization.

METHODS

Between February 2008 and August 2015, 70 patients underwent infrainguinal bypass grafts in 73 limbs using CSV. All patients lacked suitable arm or leg vein. Demographic data and patient outcomes were retrospectively collected using electronic medical records.

RESULTS

The mean age of our cohort was 70 ± 14 years, and 36 (51%) were male; 47 (67%) were white, 39 (56%) had coronary artery disease, 27 (39%) had diabetes, 56 (80%) had hypertension, and 50 (71%) were former or current smokers. Median follow-up was 304 days (interquartile range, 130-991 days). Indications for the index operation included rest pain (27%), tissue loss (55%), and prosthetic graft infection (18%); 62 of 73 (85%) bypasses were performed for critical limb ischemia, and 45 of 73 (62%) were redo operations. Distal targets included superficial femoral artery or popliteal (38%), tibial (55%), and pedal (7%). All grafts had a minimum diameter of 3 mm. At 30 days, 55 of 64 grafts (86%) were patent; 9 were lost to early follow-up. The only significant risk factors associated with 30-day failure were ABO mismatch (43% vs 10%; P = .05) and donor blood type B or AB (40% vs 9%; P = .03). Estimated overall 1-year primary patency was 35%. In a multivariate analysis, nonblack race (P = .05), donor B or AB blood type (P = .01), and bypass to a tibial or pedal target (P = .05) were independently associated with loss of primary patency. There were 20 (27%) major amputations, and all grafts in these limbs had occluded at the time of amputation. Of the 33 limbs with ischemic tissue loss that had long-term follow-up, 17 of 33 (52%) went on to graft occlusion, 10 of 33 (30%) had a major amputation, and 24 of 33 (73%) had complete healing of the index wound.

CONCLUSIONS

In the setting of a multidisciplinary team with aggressive wound care, CSV may be a reasonable choice for infrainguinal revascularization in patients with ischemic tissue loss who lack autogenous conduit. However, poor midterm to long-term patency suggests that optimal selection of patients is needed to derive meaningful clinical benefit.

Use of an Anastomotic Coupling Device for the Creation of Spliced Autogenous Grafts in Lower Extremity Revascularization

INTRODUCTION

Despite a recent rise in popularity of endovascular techniques, open bypass surgery is still required for treating many lower extremity vascular lesions. Greater saphenous vein (GSV) of adequate length and caliber for successful infrainguinal lower extremity bypass is unavailable in 15% to 45% of patients. To overcome limitations imposed by absent vein due to prior use, short vessel length, or sclerotic segments, both alternate (ie, basilic and cephalic) and GSV conduits may be "spliced" together in series via venovenostomy. Although vascular surgeons typically perform a hand-sewn venovenostomy, device-based venous coupling has been performed by plastic surgeons for many years. We therefore sought to review our experience with venous coupling for segmental lower extremity bypass graft assembly.

METHODS

A retrospective review was performed in all patients who underwent lower extremity revascularization using autogenous vein grafts spliced together with the Synovis (Birmingham, Alabama) anastomotic coupler at a single institution over a 5-year period.

RESULTS

The anastomotic coupler device was used on 5 patients for 7 venovenostomies. The mean age of patients was 66 years, and the mean follow-up period was 751 days. Two patients were lost to follow-up, while 2 other patients died of causes unrelated to their lower extremity bypass. The average time to perform venovenostomy was 3 minutes. Three patients developed stenosis of their composite graft at a site other than the venovenostomy, who were successfully treated with either angioplasty or bypass revision. One-year primary and primary-assisted patency rates were 50% and 75%, respectively.

CONCLUSIONS

Given the known benefits of the anastomotic coupling device when used for venous anastomoses in microsurgical reconstruction, transition of this device to the vascular surgery realm represents a logical progression. Although small, our series demonstrates that the anastomotic coupler can successfully be used for the formation of spliced autogenous grafts for lower extremity revascularization in the absence of adequate GSV.

Autologous alternative veins may not provide better outcomes than prosthetic conduits for below-knee bypass when great saphenous vein is unavailable

BACKGROUND

There is a need to better define the role of alternative autologous vein (AAV) segments over contemporary prosthetic conduits in patients with critical limb ischemia when great saphenous vein (GSV) is not available for use as the bypass conduit.

METHODS

Consecutive patients who underwent bypass to infrageniculate targets between 2007 and 2011 were categorized in three groups: GSV, AAV, and prosthetic. The primary outcome was graft patency. The secondary outcome was limb salvage. Cox proportional hazards regression was used to adjust for baseline confounding variables.

RESULTS

A total of 407 infrainguinal bypasses to below-knee targets were analyzed; 255 patients (63%) received a single-segment GSV, 106 patients (26%) received an AAV, and 46 patients (11%) received a prosthetic conduit. Baseline characteristics were similar among groups, with the exception of popliteal targets and anticoagulation use being more frequent in the prosthetic group. Primary patency at 2 and 5 years was estimated at 47% and 32%, respectively, for the GSV group; 24% and 23% for the AAV group; and 43% and 38% for the prosthetic group. Primary assisted patency at 2 and 5 years was estimated at 71% and 55%, respectively, for the GSV group; 53% and 51% for the AAV group; and 45% and 40% for the prosthetic group. Secondary patency at 2 and 5 years was estimated at 75% and 60%, respectively, for the GSV group; 57% and 55% for the AAV group; and 46% and 41% for the prosthetic group. In Cox analysis, primary patency (hazard ratio [HR], 0.55; P < .001; 95% confidence interval [CI], 0.404-0.758), primary assisted patency (HR, 0.57; P = .004; 95% CI, 0.388-0.831), and secondary patency (HR, 0.56; P = .005; 95% CI, 0.372-0.840) were predicted by GSV compared with AAV, but there was no difference between AAV and prosthetic grafts except for the primary patency, for which prosthetic was protective (HR, 0.38; P < .001; 95% CI, 0.224-0.629). Limb salvage was similar among groups.

CONCLUSIONS

AAV conduits may not offer a significant patency advantage in midterm follow-up over prosthetic bypasses.

Arm veins versus contralateral greater saphenous veins for lower extremity bypass reconstruction: preliminary data of a randomized study

BACKGROUND

The aim of this randomized study was to determine whether arm vein (AV) or contralateral greater saphenous vein (CGSV) is the better alternative vein source for lower extremity bypass reconstruction.

METHODS

Consecutive patients with absent ipsilateral greater saphenous vein undergoing lower extremity revascularization were allocated to group A (AV bypass) or B (CGSV bypass).

RESULTS

From 6, 2010, to 11, 2013, 64 patients (32 each group) were randomized. In all, 29 of 93 patients had to be excluded for various reasons. Median age was 76 years vs. 71 years (P = 0.01) for group A and B patients. There were no statistically significant differences regarding gender, cardiovascular risk factors, redo bypass procedures (P = 0.77), below-knee bypass procedures (P = 0.61), median bypass length (P = 0.6), and median length of incision on ipsilateral leg to perform anastomoses (P = 0.2) between group A and B patients, respectively. Incisions for vein harvest were longer in group A (P = 0.003). Overall surgical site infections (SSIs, P = 1.0) and SSI from vein harvest (P = 1.0) were equally distributed. No patient was lost to follow-up (17 vs. 18 months, P = 0.74). There was no statistically significant difference regarding primary (P = 0.77) and secondary (P = 0.25) patency rates at 1 year (group A: 52% vs. group B: 54% and group A: 72% vs. group B: 61%) and at 2 years (52% vs. 48% and 64% vs. 61%), respectively. There were 4 vs. 6 major amputations (P = 0.23) and 5 vs. 2 deaths (P = 0.1) in groups A and B during follow-up.

CONCLUSIONS

Preliminary results suggest that both AV and CGSV may serve as a secondary vein bypass graft equally well.

Antithrombotic therapy after infrainguinal bypass

OBJECTIVE

Bypass surgery is regularly performed for the treatment of critical limb ischemia, but the risk of occlusion remains significant. Antiplatelet therapy in patients with arterial disease is useful for secondary cardiovascular and bypass occlusion prevention. However, despite the common use of an antiplatelet agent, especially aspirin, which became the standard of care, the risk of graft occlusion persists. The best antithrombotic treatment for bypass patency therefore remains a matter of debate.

METHODS

We conducted a systematic literature search to identify studies and consensus reporting the use of antithrombotic treatment to prevent bypass occlusion. We excluded case reports and clinical trials with a placebo arm.

RESULTS

Aspirin remains the mainstay of treatment to improve infrainguinal bypass patency; however, the effect differs according to the bypass material used. The greatest beneficial effect of antiplatelet agents was observed with prosthetic bypasses. In such cases, the addition of clopidogrel to aspirin, for at least 1 year, in patients who benefited from a below-knee bypass graft significantly improved bypass patency (occlusion 32% vs 47% for aspirin alone; P = .02) and the amputation rate (9.4% vs 19.2% for aspirin alone; P = .03), without increasing the incidence of major hemorrhage. In contrast, antiplatelet regimens were less efficacious for autologous vein bypasses. The addition of a vitamin K antagonist (VKA) is not routinely proposed because of the increased incidence of associated major hemorrhage. The use of VKA alone, instead of aspirin, should probably be discussed in selected patients, and a combination of VKA and antiplatelet agents should be discussed in patients with venous infrainguinal bypasses considered to be at a high risk for occlusion.

CONCLUSIONS

Although aspirin remains the first-line treatment to prevent infrainguinal bypass occlusion, future studies are needed to define stronger recommendations.

Distal anastomotic vein adjunct usage in infrainguinal prosthetic bypasses

OBJECTIVE

Single-segment saphenous vein remains the optimal conduit for infrainguinal revascularization. In its absence, prosthetic conduit may be used. Existing data regarding the significance of anastomotic distal vein adjunct (DVA) usage with prosthetic grafts are based on small series.

METHODS

This is a retrospective cohort analysis derived from the regional Vascular Study Group of New England as well as the Brigham and Women's hospital database. A total of 1018 infrainguinal prosthetic bypass grafts were captured in the dataset from 73 surgeons at 15 participating institutions. Propensity scoring and 3:1 matching was performed to create similar exposure groups for analysis. Outcome measures of interest included: primary patency, freedom from major adverse limb events (MALEs), and amputation free survival at 1 year as a function of vein patch utilization. Time to event data were compared with the log-rank test; multivariable Cox proportional hazard models were used to evaluate the adjusted association between vein cuff usage and the primary end points. DVA was defined as a vein patch, cuff, or boot in any configuration.

RESULTS

Of the 1018 bypass operations, 94 (9.2%) had a DVA whereas 924 (90.8%) did not (no DVA). After propensity score matching, 88 DVAs (25%) and 264 no DVAs (75%) were analyzed. On univariate analysis of the matched cohort, the DVA and no DVA groups were similar in terms of mean age (70.0 vs 69.0; P = .55), male sex (58.0% vs 58.3%; P > .99), and preoperative characteristics such as living at home (93.2% vs 94.3%; P = .79) and independent ambulatory status (72.7% vs 75.7%; P = .64). The DVA and no DVA groups had similar rates of major comorbidities such as hypertension chronic obstructive pulmonary disease, diabetes mellitus, coronary artery disease, and dialysis dependence (P > .05 for all). Likewise, they had similar rates of distal origin grafts (13.6% vs 12.5%; P = .85), critical limb ischemia indications (P = .53), and prior arterial bypass (58% vs 47%; P = .08). The DVA group had a higher rate of completion angiogram performed (55.7% vs 37.5%; P =.002) and were more likely to be discharged on coumadin (53.4% vs 37.1%; P =.01). By multivariable analysis, use of a distal DVA was protective against MALEs (hazard ratio, 0.36; 95% confidence interval, 0.14-0.90; P = .03).

CONCLUSIONS

This contemporary multi-institutional propensity-matched study demonstrates that patients that receive distal anastomotic vein adjuncts as part of infrainguinal prosthetic bypass operations in general have more extreme comorbidities and more technically challenging operations based on level of target vessel and prior bypass attempts. After propensity-matched analysis, the use of a DVA may protect against MALEs in prosthetic bypass surgery and should be considered when feasible.