Biological Conduit Research Articles

Intravascular lithotripsy-assisted intervention in patients with congenital heart disease.

The use of intravascular lithotripsy (IVL) in patients with calcified coronary and peripheral arterial disease is now commonplace; however, its use in procedures specific to congenital heart disease is rare, with a very limited published case-based experience to date. The authors report the outcomes of 4 patients with congenital heart disease who underwent IVL-assisted transcatheter procedures in the effort to inform future operators as to the potential benefits and risks of this technology in this patient population. Four patients underwent IVL-assisted transcatheter procedures including branch pulmonary artery stenting, aortic coarctation stenting, and transcatheter pulmonary valve replacement. All 4 patients underwent successful IVL-assisted implantation of large stents in highly calcified native or surgically implanted biological conduits without significant complications. The use of IVL-assisted interventions in patients with severe native or surgical calcified vascular conduits is feasible and may be a useful adjunct in conduit stent implantation and dilation. Vascular injury during angioplasty of calcified vessels and conduits remains a concern despite the use of lithotripsy, and covered stent implantation should be considered prior to aggressive dilation in order to reduce the risk of catastrophic rupture.

Biological conduits based on spider silk for reconstruction of extended nerve defects.

The availability of appropriate conduits remains an obstacle for successful reconstruction of long-distance nerve defects. In previous sheep trials, we were able to bridge 6 cm nerve gaps with nerve conduits based on spider silk fibers with full functional outcomes. Here, we describe the first application of spider silk for nerve repair inhumans. Four patients with extended nerve defects (>20 cm) underwent nerve reconstruction by interposition of conduits that were composed of spider silk fibers contained in autologous veins. The longitudinal luminal fibers (approx.2500 fibers per graft) consisted of drag line silkfrom Trichonephila spiders. All patients were evaluated between 2and 10 years postreconstruction, clinically, and byneurography. In all patients, primary wound healing and no adverse reactions to the implanted spider silk material wereobserved. Patients regained the following relevant functions: protective sensibility, full flexor function with near-normal grasp and powerful function after microvascular gracilis muscle transfer, and key grip function and gross finger flexion after additional tenodesis. One patient with sciatic nerve reconstruction developed protective sensibility of the lower leg, foot, and gait, enabling normal walking and jogging. No neuroma formation or neuropathic or chronic pain occurred in any of the patients. For patients with extended peripheral nerve defects in the extremities, use of conduits based on spider silk fibers offers the possibility of restoring sensory function and protection from neuroma. This kind of nerve bridges provides new perspectives for the reconstruction of complex and long-distance nerve defects.

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

ObjectiveThe 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. MethodsPatients 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. ResultsDemographics 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. ConclusionsImplanted 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.

Silicon-induced biofilm improves peripheral nerve defect in rats mediated by VEGF/VEGFR2/ERK

ABSTRACT Background: Injury of peripheral nerve capable of regeneration with much poorer prognosis affects people’s life quality. The recovery of nerve function after transplantation for peripheral nerve injury remain a worldwide problem. Silicon-induced biofilms as vascularized biological conduits can promote nerve regeneration by encapsulating autologous or allogeneic nerve graft. Objective: We proposed to explore the effect of silicon-induced biofilms on nerves regeneration and whether the VEGF/VEGFR2/ERK pathway was involved in the present study. Methods: Biofilms around the transplanted nerves in peripheral nerve injury rats were induced by silicon. Vascularization and proteins related to VEGF/VEGFR2/ERK were measured. Pathology and morphology of nerves were investigated after encapsulating the transplanted nerves by silicon-induced biofilms. Results: Our results indicated that the biofilms induced by silicon for 6 weeks showed the most intensive vascularization and the optimal effect on nerve regeneration. Moreover, silicon-induced biofilms for 4, 6 and 8 weeks could significantly secrete VEGF with the highest content at week 6 after induction. VEGFR2, VEGF, p-VEGFR2, ERK1, ERK2, p-ERK1 and p-ERK2 were expressed in the biofilms. p-VEGFR2, p-ERK1 and p-ERK2 expression were different at each time point and significantly increased at week 6 compared with that at week 4 or week 8 which was consistent with that 6 week of was the optimum time for biofilms induction to improve the nerve repair after peripheral nerve injury. Conclusion: Our results suggested that combination of silicon-induced autologous vascularized biofilm and autologous transplantation may promote the repair of rat sciatic nerve defect quickly through VEGF/VEGFR2/ERK pathway.

Nanotechnology Innovations in Pediatric Cardiology and Cardiovascular Medicine: A Comprehensive Review.

(1) Background: Nanomedicine, incorporating various nanoparticles and nanomaterials, offers significant potential in medical practice. Its clinical adoption, however, faces challenges like safety concerns, regulatory hurdles, and biocompatibility issues. Despite these, recent advancements have led to the approval of many nanotechnology-based products, including those for pediatric use. (2) Methods: Our approach included reviewing clinical, preclinical, and animal studies, as well as literature reviews from the past two decades and ongoing trials. (3) Results: Nanotechnology has introduced innovative solutions in cardiovascular care, particularly in managing myocardial ischemia. Key developments include drug-eluting stents, nitric oxide-releasing coatings, and the use of magnetic nanoparticles in cardiomyocyte transplantation. These advancements are pivotal for early detection and treatment. In cardiovascular imaging, nanotechnology enables noninvasive assessments. In pediatric cardiology, it holds promise in assisting the development of biological conduits, synthetic valves, and bioartificial grafts for congenital heart defects, and offers new treatments for conditions like dilated cardiomyopathy and pulmonary hypertension. (4) Conclusions: Nanomedicine presents groundbreaking solutions for cardiovascular diseases in both adults and children. It has the potential to transform cardiac care, from enhancing myocardial ischemia treatment and imaging techniques to addressing congenital heart issues. Further research and guideline development are crucial for optimizing its clinical application and revolutionizing patient care.

Revision Surgery for Recurrent Morton Neuroma with Use of a Collagen Conduit.

Revision Surgery for Recurrent Morton Neuroma with Use of a Collagen Conduit.

The Human Acellular Vessel (HAV) as a vascular conduit for infrainguinal arterial bypass.

Autologous vein is the optimal conduit for peripheral arterial bypass surgery, a standard recently highlighted by findings from the BEST-CLI trial. The Human Acellular Vessel is a novel biologic conduit produced using regenerative medicine technologies with structural and mechanical properties like a human blood vessel. Not yet approved by the United States Food and Drug Administration, the Human Acellular Vessel is being studied as an alternative bypass conduit in patients with peripheral arterial disease, vascular injury, and those in need of arteriovenous access for hemodialysis. This report describes and illustrates the technical aspects of intraoperative handling specific to the use of this new and innovative technology.

Outcomes of Arterial Bypass With the Human Acellular Vessel for Chronic Limb-Threatening Ischemia Performed Under the FDA Expanded Access Program

ObjectiveTo report outcomes of the human acellular vessel (HAV) implanted for limb salvage through the Food and Drug Administration (FDA) Expanded Access Program for patients with chronic limb-threatening ischemia with no autologous conduit. MethodsThe HAV is a bioengineered vascular conduit designed with human vascular smooth muscle cells. The product is under regulatory study. From April 2019 to November 2021, the HAV was implanted in 14 patients (12 men; mean age, 62±14 years) at 3 US centers. Each case was performed with a single-use investigational new drug Expanded Access Program issued by the FDA. Institutional review board approval was obtained; technical and clinical outcomes were analyzed. ResultsA single 6-mm-diameter (40-cm-long) HAV was implanted in 9 patients; 5 patients required 2 HAVs sewn together as a composite. Technical success was 100%. Median follow-up was 12 (range, 1 to 41) months. Primary and secondary patency rates were 72% and 81% at 12 months; assisted primary patency was attained in 4 patients. Amputation-free survival was 93% at 6 months and 77% at 12 months. All patients with a patent HAV experienced clinical improvement with no HAV-related infections or adverse events. There were 4 deaths in the cohort, late mortality unrelated to the HAV. ConclusionThe HAV is a safe and effective “off-the-shelf” biologic conduit. This experience from the FDA Expanded Access Program in this population with few alternative limb salvage options will help guide regulatory deliberations for patients with lower extremity ischemia and no autologous bypass conduit options.

Aortic Root Replacement Surgery-A Center Experience with Biological Valve Prostheses.

Outcomes after surgical aortic root replacement using different valved conduits are rarely reported. The present study shows the experience of a single center with the use of the partially biological LABCOR (LC) conduit and the fully biological BioIntegral (BI) conduit. Special attention was paid to preoperative endocarditis. All 266 patients who underwent aortic root replacement by an LC conduit (n = 193) or a BI conduit (n = 73) between 01/01/2014 and 31/12/2020 were studied retrospectively. Dependency on an extracorporeal life support system preoperatively and congenital heart disease were exclusion criteria. For patients with (n = 67) and without (n = 199) preoperative endocarditis subanalyses were made. Patients treated with a BI conduit were more likely to have diabetes mellitus (21.9 vs. 6.7%, p < 0.001), previous cardiac surgery (86.3 vs. 16.6%; p < 0.001), permanent pacemaker (21.9 vs. 2.1%; p < 0.001), and had a higher EuroSCORE II (14.9 vs. 4.1%; p < 0.001). The BI conduit was used more frequently for prosthetic endocarditis (75.3 vs. 3.6%; <0.001), and the LC conduit was used predominantly for ascending aortic aneurysms (80.3 vs. 41.1%; <0.001) and Stanford type A aortic dissections (24.9 vs. 9.6%; p = 0.006). The LC conduit was used more often for elective (61.7 vs. 47.9%; p = 0.043) and emergency (27.5 vs. 15.1%; p = 0-035) surgeries, and the BI conduit for urgent surgeries (37.0 vs. 10.9%; p < 0.001). Conduit sizes did not differ significantly, with a median of 25 mm in each case. Surgical times were longer in the BI group. In the LC group, coronary artery bypass grafting and proximal or total replacement of the aortic arch were combined more frequently, whereas in the BI group, partial replacement of the aortic arch were combined. In the BI group, ICU length of stay and duration of ventilation were longer, and rates of tracheostomy and atrioventricular block, pacemaker dependence, dialysis, and 30-day mortality were higher. Atrial fibrillation occurred more frequently in the LC group. Follow-up time was longer and rates of stroke and cardiac death were less frequent in the LC group. Postoperative echocardiographic findings at follow-up were not significantly different between conduits. Survival of LC patients was better than that of BI patients. In the subanalysis of patients with preoperative endocarditis, significant differences between the used conduits were found with respect to previous cardiac surgery, EuroSCORE II, aortic valve and prosthesis endocarditis, elective operation, duration of operation, and proximal aortic arch replacement. For patients without preoperative endocarditis, significant differences were observed concerning previous cardiac surgery, pacemaker implantation history, duration of procedure, and bypass time. The Kaplan-Meier curves for the subanalyses showed no significant differences between the used conduits. Both biological conduits studied here are equally suitable in principle for complete replacement of the aortic root in all aortic root pathologies. The BI conduit is often used in bail-out situations, especially in severe endocarditis, without being able to show a clinical advantage over the LC conduit in this context.

Spotlight in Plastic Surgery: January 2023.

Spotlight in Plastic Surgery: January 2023.

Biological nerve conduit model with de-epithelialized human amniotic membrane and adipose-derived mesenchymal stem cell sheet for repair of peripheral nerve defects.

In this study, a biological conduit, consisting of an adipocyte-derived mesenchymal stem cell (AdMSCs) sheet and amniotic membrane (AM), was designed for the reconstruction of peripheral nerve defects. To evaluate the effect of the produced conduit on neural regeneration, a 10-mm sciatic nerve defect was created in rats, and experiments were carried out on six groups, i.e., sham control group (SC), negative control group (NC), nerve autograft group (NG), the biological conduit (AdMSCs + AM) group, the commercial PGA tube conduit (PGA) group, and the conduit only consisting of AM (AM) group. The effects of different nerve repair methods on the peripheral nerve and gastrocnemius muscle were evaluated by functional, histological, and immunohistochemical tests. When the number of myelinated axons was compared between the groups of AdMSCs + AM and PGA, it was higher in the AdMSCs + AM group (p < 0.05). The percentage of gastrocnemius collagen bundle area of AdMSCs + AM group was found to be statistically lower than the PGA group (p < 0.05). The muscle fiber diameter of AdMSCs + AM group was lower than that of the NG group, but significantly higher than that of the PGA group and the AM group (p < 0.001). Muscle weight index was significantly higher in the AdMSCs + AM group compared to the PGA group (p < 0.05). It was observed that nerve regeneration was faster in the AdMSCs + AM group, and there was an earlier improvement in pin-prick score and sciatic functional index compared to the PGA group and the AM group. In conclusion, the biological conduit prepared from the AdMSCs sheet and AM is regarded as a new biological conduit that can be used as an alternative treatment method to nerve autograft in clinical applications.

Combining chitin biological conduits with injectable adipose tissue-derived decellularised matrix hydrogels loaded with adipose-derived mesenchymal stem cells for the repair of peripheral nerve defects in rats

Mesenchymal stem cells (MSCs) have shown potential for the repair of defective tissues and peripheral nerve injuries. However, local treatment alone may lead to cell loss, low viability, and diminished paracrine action owing to the lack of effective biological scaffolds. To improve the therapeutic effects of MSCs, bioactive scaffolds that mimic the stem cell microenvironment in vivo should be constructed. We developed an injectable decellularised matrix hydrogel (DAM-gel) to simulate the stem cell microenvironment using combined physical, chemical, and enzymatic digestions of human adipose tissues. The DAM-gel was loaded with rat adipose-derived mesenchymal stem cells (ADSCs) to repair sciatic nerve defects. Compared with ADSCs alone, the ADSC-loaded DAM-gel promoted the proliferation of Schwann cells in vitro, which are important in sciatic nerve regeneration. Chitin biological conduits filled with ADSC-DAM-gel composites were designed to bridge the sciatic nerve defects. Axonal regeneration and the recovery of neurological function in the ADSC-DAM-gel group increased post-surgery compared with the control group (blank conduit, ADSCs, and DAM-gel group), as confirmed by a CatWalk gait analysis, electrophysiology, and nerve/muscle histology. The ADSC-loaded DAM-gel-treated rats retained the improved peripheral nerve regeneration. Therefore, DAM-gels have great potential for enhancing the repair capacity of ADSCs in peripheral nerve defects.

Long-term outcomes of aortic root procedures for heterogenous ascending aneurysm disease in bicuspid aortic valve syndrome

ObjectiveSurgery for ascending aneurysms in bicuspid aortic valve syndrome primarily includes Bentall root replacement, aortic valve replacement with supracoronary ascending aorta replacement (AVRSCAAR), and valve-sparing root reimplantation (VSRR). Comparative analysis of long-term clinical and functional outcomes of these procedures is detailed. MethodsFrom 1997 to 2017, 635 patients with bicuspid aortic valve undergoing root complex-focused procedures electively were stratified by valvulopathy (ie, aortic stenosis vs aortic insufficiency) and substratified into ascending or root aneurysm phenotype. Inverse probability weights were calculated to adjust for baseline differences. ResultsKaplan-Meier curves for all-cause mortality demonstrated no difference between Bentall versus AVRSCAAR for aortic stenosis and aortic insufficiency presentations (log-rank P > .05). In patients with aortic stenosis, multivariable Cox regression showed significantly decreased risk of stroke for biologic AVRSCAAR (hazard ratio, 0.04; P = .013). Aortic reoperation rates were similar for biologic versus mechanical valves (P = .353).In patients with aortic insufficiency, similar long-term mortality (hazard ratio, 0.95; P = .93), but lower stroke risk in biologic AVRSCAAR group by Cox regression, and lower aortic reoperation rate was noted (coefficient < 0.01; P < .001). Comparing Bentall to VSRR, mortality (hazard ratio, 0.12; P = .022) was significantly improved in patients undergoing VSRR, but recurrence of moderate or greater aortic insufficiency was higher in VSRR by multistate model (beta coefficient 2.63; P < .001). ConclusionsA tailored approach to heterogeneous ascending aneurysm pathologies in bicuspid aortic valve syndrome utilizing Bentall, AVRSCAAR, and VSRR procedures renders excellent long-term clinical and functional outcomes, with biologic conduits showing equivalent to improved clinical outcomes.

Evaluation Of The Artegraft Conduit For Lower Extremity Revascularization: Retrospective Analysis Of Outcomes When Used In The Situation Of No Available Autologous Saphenous Vein For Conduit In Lower Extremity Bypass Procedures

Artegraft is a biological conduit made from bovine carotid artery. Over the years, there have been a multitude of studies evaluating the outcomes of Artegraft in arteriovenous access for hemodialysis. There are limited reports on its use in lower extremity revascularization. Use of other biologic grafts such as the umbilical vein graft showed superior outcome compared with other non-biologic grafts in lower extremity bypass. The objective of this paper was to evaluate our experience utilizing Artegraft in lower extremity bypasses when no native venous conduit was available.

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.

Duplicate Great Saphenous Vein Utilization for Long Segment Tibial Bypass Without Need for Spliced Re-Anastomosis.

There is significant benefit to utilizing autologous venous conduit in lower extremity arterial bypass surgery. Specifically, improved patency is well documented relative to prosthetic or non-autologous biological conduits. The smaller caliber the target artery, the more critical using an autologous conduit becomes in striving to achieve long term graft survival. Another benefit to venous conduit is resistance to infection. Presented herein are the technique and images of a duplicate great saphenous vein (GSV) system with a common trunk being utilized to create a single long autologous venous conduit. Intraoperative images as well as conceptual drawing are provided. The non-reversed segment of the bypass is treated with a valvulatome. This allows for creation of a non-spliced autologous conduit when the distal aspect of the primary GSV is too diminutive for bypass. Surveillance duplex imaging 3months after surgery revealed no evidence of stenosis in the bypass and a normalization of the ABI. The area corresponding to the repair of the common trunk was identified on duplex and noted to have a robust diameter. He is doing well with full resolution of rest pain and claudication symptoms. This technique of utilizing a duplicate greater saphenous vein system to maintain a single lower extremity autologous venous conduit for arterial bypass is beneficial to keep in the armamentarium of vascular surgeons.

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

ObjectiveSingle 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. MethodsThe 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. ResultsWe 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. ConclusionsIn 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.

Alternative Conduits Have Worse Outcomes Than Prosthetic Grafts for Infrainguinal Bypass

Single-segment great saphenous vein (ssGSV) is the preferred conduit for infrainguinal bypass. Alternative autologous conduits (AACs) and nonautologous biologic conduits (NABCs) are thought to be a better alternative to traditional prosthetic conduits (PCs) in the absence of the ssGSV. We analyzed the outcomes of these alternative conduits in lower extremity bypass (LEB) in patients with chronic limb threatening ischemia. The Vascular Quality Initiative LEB database from 2003 to 2020 was queried to identify LEB in patients with chronic limb threatening ischemia. The primary outcomes were graft patency, major adverse limb events (MALE), and MALE-free survival at 1 year. Standard statistical methods were used as appropriate. We identified 22,671 LEB procedures (12,810 ssGSVs, 6002 PCs, 1907 AACs, and 1952 NABCs). Compared with the ssGSV 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 had been less ambulatory at baseline. The PC, AAC, and NABC groups had significantly higher rates of postoperative morbidity compared with the ssGSV group. The PC group had higher 30-day mortality compared with the ssGSV, AAC, and NABC groups (3% PC vs 2% ssGSV, 2% AAC, and 2% NABC; P = .049). The PC and NABC groups had higher 1-year mortality compared with the ssGSV and AAC groups (13% PC and 13% NABC vs 10% ssGSV and 10% AAC; P = .02). In an adjusted Cox regression model (Fig; stratified by infrageniculate target and adjusted for age, comorbidities, and prior vascular interventions), 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 compared with PC. 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 PC. However, PC was not significantly different from ssGSV. In the absence of ssGSV, alternative autologous or nonautologous biologic materials do not confer a benefit with regard to graft patency or MALE compared with PCs. The increased operating time or costs associated with the use of these conduits was not justified from the results from the present study.

Fibrin Glue and Conduit Form a Composite Structure in Digital Nerve Repair.

Repair of severed nerves without autograft or allograft has included suture, suture with glue alone, suture with conduit and suture with glue augmentation to conduit, where use of conduit is considered for separation of the nerve ends from 5 mm to 3 cm. Repairs must not only serve acutely to provide apposition of nerve ends but must enable the healing of the nerve. Using biological conduit can place suture at the ends of the conduit while fibrin glue alone eliminates suture but with limited strength. The combination of conduit and glue offers the growth guidance of conduit with sufficient strength from the glue to maintain the nerve within the conduit. The role of fibrin glue in the integrity of the repair remains an open question, however. We sought to determine the factors in the strength of a glue-conduit-nerve construct and include consideration of standard suture repair. Fresh-frozen cadaveric digital nerves were repaired with suture alone, with glue alone or with suture and glue together and then loaded to failure. Previously tested specimens with conduit, suture and glue were considered for comparison. The suture alone (2.02 N) and suture with glue (2.24 N) were not statistically different from each other but were statistically stronger than glue alone (0.15 N). When compared to the earlier results of the strength of conduit with glue (0.65 N), these simple results show that the glue and conduit act together. The increased area over which the glue adheres to the nerve and conduit creates a composite structure stronger than either alone.

Alternative Autologous and Biologic Conduits Have Worse Outcomes Than Prosthetic Grafts for Infrainguinal Bypass

Single segment great saphenous vein (ssGSV) 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 ssGSV. In this study, we analyzed the outcomes of these alternative conduits in lower extremity bypasses (LEB).