Hemodynamics and Wall Mechanics of Vascular Graft Failure.

Blood vessels are subjected to complex biomechanical loads, primarily from pressure-driven blood flow. Abnormal loading associated with vascular grafts, arising from altered hemodynamics or wall mechanics, can cause acute and progressive vascular failure and end-organ dysfunction. Perturbations to mechanobiological stimuli experienced by vascular cells contribute to remodeling of the vascular wall via activation of mechanosensitive signaling pathways and subsequent changes in gene expression and associated turnover of cells and extracellular matrix. In this review, we outline experimental and computational tools used to quantify metrics of biomechanical loading in vascular grafts and highlight those that show potential in predicting graft failure for diverse disease contexts. We include metrics derived from both fluid and solid mechanics that drive feedback loops between mechanobiological processes and changes in the biomechanical state that govern the natural history of vascular grafts. As illustrative examples, we consider application-specific coronary artery bypass grafts, peripheral vascular grafts, and tissue-engineered vascular grafts for congenital heart surgery as each of these involves unique circulatory environments, loading magnitudes, and graft materials.

Carotid Artery Bypass Surgery of In-Body Tissue Architecture-Induced Small-Diameter Biotube in a Goat Model: A Pilot Study.

Biotubes are autologous tubular tissues developed within a patient's body through in-body tissue architecture, and they demonstrate high potential for early clinical application as a vascular replacement. In this pilot study, we used large animals to perform implantation experiments in preparation for preclinical testing of Biotube. The biological response after Biotube implantation was histologically evaluated. The designed Biotubes (length: 50 cm, internal diameter: 4 mm, and wall thickness: 0.85 mm) were obtained by embedding molds on the backs of six goats for a predetermined period (1-5 months). The same goats underwent bypass surgery on the carotid arteries using Biotubes (average length: 12 cm). After implantation, echocardiography was used to periodically monitor patency and blood flow velocity. The maximum observation period was 6 months, and tissue analysis was conducted after graft removal, including the anastomosis. All molds generated Biotubes that exceeded the tensile strength of normal goat carotid arteries, and eight randomly selected Biotubes were implanted. Thrombotic occlusion occurred immediately postoperatively (1 tube) if anticoagulation was insufficient, and two tubes, with insufficient Biotube strength (<5 N), were ruptured within a week. Five tubes maintained patency for >2 months without aneurysm formation. The spots far from the anastomosis became stenosed within 3 months (3 tubes) when Biotubes had a wide intensity distribution, but the shape of the remaining two tubes remained unchanged for 6 months. The entire length of the bypass region was walled with an αSMA-positive cell layer, and an endothelial cell layer covered most of the lumen at 2 months. Complete endothelial laying of the luminal surface was obtained at 3 months after implantation, and a vascular wall structure similar to that of native blood vessels was formed, which was maintained even at 6 months. The stenosis was indicated to be caused by fibrin adhesion on the luminal surface, migration of repair macrophages, and granulation formation due to the overproliferation of αSMA-positive fibroblasts. We revealed the importance of Biotubes that are homogeneous, demonstrate a tensile strength > 5 N, and are implanted under appropriate antithrombotic conditions to achieve long-term patency of Biotube. Further, we clarified the Biotube regeneration process and the mechanism of stenosis. Finally, we obtained the necessary conditions for a confirmatory implant study planned shortly.

Silica nanoparticles enhance interfacial self-adherence of a multi-layered extracellular matrix scaffold for vascular tissue regeneration.

PURPOSE: Based on the clinical need for grafts for vascular tissue regeneration, our group developed a customizable scaffold derived from the human amniotic membrane. Our approach consists of rolling the decellularized amniotic membrane around a mandrel to form a multilayered tubular scaffold with tunable diameter and wall thickness. Herein, we aimed to investigate if silica nanoparticles (SiNP) could enhance the adhesion of the amnion layers within these rolled grafts. METHODS: To test this, we assessed the structural integrity and mechanical properties of SiNP-treated scaffolds. Mechanical tests were repeated after six months to evaluate adhesion stability in aqueous environments. RESULTS: Our results showed that the rolled SiNP-treated scaffolds maintained their tubular shape upon hydration, while non-treated scaffolds collapsed. By scanning electron microscopy, SiNP-treated scaffolds presented more densely packed layers than untreated controls. Mechanical analysis showed that SiNP treatment increased the scaffold's tensile strength up to tenfold in relation to non-treated controls and changed the mechanism of failure from interfacial slipping to single-point fracture. The nanoparticles reinforced the scaffolds both at the interface between two distinct layers and within each layer of the extracellular matrix. Finally, SiNP-treated scaffolds significantly increased the suture pullout force in comparison to untreated controls. CONCLUSION: Our study demonstrated that SiNP prevents the unraveling of a multilayered extracellular matrix graft while improving the scaffolds' overall mechanical properties. In addition to the generation of a robust biomaterial for vascular tissue regeneration, this novel layering technology is a promising strategy for a number of bioengineering applications.

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.

Inflow Artery Aneurysmal Degeneration After Long Term Native Arteriovenous Fistula for Haemodialysis.

OBJECTIVE: Inflow arterial aneurysms are a rare but serious complication after long term arteriovenous fistulae (AVF), probably due to arterial wall remodelling after an increase in flow and shear stress, and kidney transplantation with immunosuppressive therapy. This study aimed to describe the outcomes of surgical treatment and long term follow up in a large cohort. METHODS: This prospective cohort study collected data from patients with a true inflow artery aneurysm after AVF creation that was surgically repaired between 2010 and 2022. Anastomotic and infected aneurysms or post-puncture pseudoaneurysms were excluded. Demographic data, access characteristics, symptoms, treatment strategies, and long term follow up were recorded; patency was estimated using Kaplan-Meier survival analysis. RESULTS: During the study period, 28 patients (64% men, mean age 60.1 years) were treated surgically for aneurysmal degeneration of the axillary or brachial (n = 23) or radial (n = 5) artery after an AVF (10 distal, 18 proximal) performed a mean of 18.3 ± SD 7.9 years previously. Most AVFs were ligated or thrombosed, while all patients except one had previously received kidney transplants. Most of the cases (n = 18) were symptomatic: 13 with pain or swelling, four with distal embolisation, and one rupture. They were repaired by aneurysm partial excision and graft interposition (11 great saphenous vein, six ipsilateral basilic vein, three cephalic vein, and two PTFE graft), ligation (n = 3), or direct end to end anastomosis (n = 3). No major complications occurred before discharge, after a mean hospital stay of 2.4 days. After a mean follow up of 4.8 ± 3.3 years, three cases presented complications: two recurrent proximal brachial aneurysms were repaired with an additional proximal interposition graft (one with further late infected pseudoaneurysm) and an asymptomatic post-traumatic graft thrombosis. Five year primary and secondary patency was 84% and 96%, respectively. CONCLUSION: Aneurysmal degeneration of the inflow artery is an unusual complication during long term follow up of AVFs. Aneurysm excision and, in general, autogenous graft interposition using the saphenous or ipsilateral arm vein is a safe and effective strategy.

Reparación del eje carotídeo con injerto autólogo por sangrado recurrente posamigdalectomía en edad pediátrica / Carotid axis repair with autologous vein graft due to recurrent post-tonsillectomy bleeding in a child

Introducción: el sangrado es una complicación común después de una amigdalectomía y habitualmente se tratacon cauterización del lecho quirúrgico. Sin embargo, en algunos pacientes, cuando el sangrado es secundario auna lesión vascular, es necesaria la ligadura o la embolización del vaso lesionado.Caso clínico: presentamos el caso de un paciente de 7 años de edad que requirió reparación y revascularizacióndel eje carotídeo izquierdo con injerto autólogo debido a sangrado recurrente y refractario a embolización de laarteria carótida externa izquierda posamigdalectomía.(AU)

Background: bleeding is a very common complication after tonsillectomy and is often treated through cauter-ization of the tonsillar bed. However, in some cases ligation or embolization of the source of the bleeding due tovascular injury is deemed necessary.Case report: this is the case of a 7-year-old boy that underwent repair and revascularization of his left carotid axiswith an autologous vascular graft due to recurrent bleeding postonsillectomy refractory to previous embolizationof the left external carotid artery.(AU)

The comparison of the short and mid-term results of endovascular interventions and bypass graft surgery in the treatment of patients with intermittent claudication complaints because of isolated femoropopliteal artery disease.

BACKGROUND: Intermittent Claudication (IC) is exercise pain seen in lower extremity arterial diseases. If it is left untreated, it may be the initial sign of a process leading to amputation. In the present study, the purpose was to compare the postoperative early and mid-term results of the patients who were treated with endovascular methods and those who underwent bypass graft surgery in the treatment due to IC complaints because of isolated Femoropopliteal Arterial Disease. METHOD: Postoperative first-month, sixth-month, and 12th-month follow-up results, procedure requirements, and demographic characteristics of the 153 patients who underwent femoropopliteal bypass because of isolated Femoropopliteal Arterial Disease and 294 patients who underwent endovascular intervention in our hospital between January 2015 and May 2020 were compared in the study. RESULTS: It was found in demographic characteristics that endovascular intervention was performed more frequently in smokers and graft bypass surgery was performed more frequently in hyperlipidemic patients, and the results were found to be statistically significant. High amputation rates were detected at statistically significant levels in diabetic and hypertriglycemic patients and 1-year primary patency rates were found to be higher in patients who underwent graft bypass surgery. No differences were detected between the two methods in terms of mortality. CONCLUSION: Interventional treatment modalities must be considered for patients with isolated Femoropopliteal Arterial Disease whose symptoms persist despite exercise and the best medical treatment. We think that Bypass Graft Surgery has more positive results than endovascular interventions when short and medium-term amputation, repetitive intervention needs, and changes in quality of life are compared in patients who receive the same medical treatment.

Calcification of Synthetic Vascular Grafts: A Systematic Review.

Objective: Calcification of vascular grafts, including polyethylene terephthalate (PET) and expanded polytetrafluoroethylene (ePTFE) grafts may contribute to graft failure, but is under reported. The aim of this study was to review the literature to assess whether vascular graft calcification is deleterious to vascular graft outcomes. Data sources: The Medline and Embase databases were searched. Review methods: A systematic literature search according to PRISMA Guidelines was performed using a combined search strategy of MeSH terms. The MeSH terms used were "calcification, physiologic", "calcinosis", "vascular grafting", "blood vessel prosthesis", "polyethylene terephthalates", and "polytetrafluoroethylene". Results: The systematic search identified 17 cases of PET graft calcification and 73 cases of ePTFE graft calcification over a 35 year period. All cases of PET graft calcification were reported in grafts explanted for graft failure. The majority of cases of ePTFE graft calcification were unexpectedly noted in grafts used during cardiovascular procedures and subsequently removed. Conclusion: Calcification of synthetic vascular grafts is under reported but can compromise the long term performance of the grafts. More data, including specific analysis of radiological findings as well as explant analysis are needed to obtain a more sensitive and specific analysis of the prevalence and incidence of vascular graft calcification and the impact of calcification on synthetic graft outcomes.

Ligamentum teres hepatis as a graft for portal and/or superior mesenteric vein reconstruction: From bench to bedside.

BACKGROUND: Pancreaticoduodenectomy combined with portal vein (PV) and/or superior mesenteric vein (SMV) resection in patients with pancreaticobiliary malignancy has become a common surgical procedure. There are various grafts currently used for PV and/or SMV reconstruction, but each of these grafts have certain limitations. Therefore, it is necessary to explore novel grafts that have an extensive resource pool, are low cost with good clinical application, and are without immune response rejection or additional damage to patients. AIM: To observe the anatomical and histological characteristics of the ligamentum teres hepatis (LTH) and evaluate PV/SMV reconstruction using an autologous LTH graft in pancreaticobiliary malignancy patients. METHODS: In 107 patients, the post-dilated length and diameter in resected LTH specimens were measured. The general structure of the LTH specimens was observed by hematoxylin and eosin (HE) staining. Collagen fibers (CFs), elastic fibers (EFs), and smooth muscle (SM) were visualized by Verhoeff-Van Gieson staining, and the expression of CD34, factor VIII-related antigen (FVIIIAg), endothelial nitric oxide synthase (eNOS), and tissue type plasminogen activator (t-PA) were detected using immunohistochemistry in LTH and PV (control) endothelial cells. PV and/or SMV reconstruction using the autologous LTH was conducted in 26 patients with pancreaticobiliary malignancies, and the outcomes were retrospectively analyzed. RESULTS: The post-dilated length of LTH was 9.67 ± 1.43 cm, and the diameter at a pressure of 30 cm H2O was 12.82 ± 1.32 mm at the cranial end and 7.06 ± 1.88 mm at the caudal end. Residual cavities with smooth tunica intima covered by endothelial cells were found in HE-stained LTH specimens. The relative amounts of EFs, CFs and SM in the LTH were similar to those in the PV [EF (%): 11.23 ± 3.40 vs 11.57 ± 2.80, P = 0.62; CF (%): 33.51 ± 7.71 vs 32.11 ± 4.82, P = 0.33; SM (%): 15.61 ± 5.26 vs 16.74 ± 4.83, P = 0.32]. CD34, FVIIIAg, eNOS, and t-PA were expressed in both LTH and PV endothelial cells. The PV and/or SMV reconstructions were successfully completed in all patients. The overall morbidity and mortality rates were 38.46% and 7.69%, respectively. There were no graft-related complications. The postoperative vein stenosis rates at 2 wk, 1 mo, 3 mo and 1 year were 7.69%, 11.54%, 15.38% and 19.23%, respectively. In all 5 patients affected, the degree of vascular stenosis was less than half of the reconstructed vein lumen diameter (mild stenosis), and the vessels remained patent. CONCLUSION: The anatomical and histological characteristics of LTH were similar to the PV and SMV. As such, the LTH can be used as an autologous graft for PV and/or SMV reconstruction in pancreaticobiliary malignancy patients who require PV and/or SMV resection.

Early Diagnosis and Intervention Are Needed for a Reasonable Prognosis of Thromboangiitis Obliterans.

Background: Thromboangiitis obliterans (TAO) poses a higher risk of amputation than atherosclerosis obliterans. It is characterized by onset at a relatively young age. There are currently no clear treatment guidelines for TAO other than smoking cessation. In this study, we aimed to identify factors that could influence a favorable prognosis of TAO. Methods: From January 2009 to December 2019, we retrospectively reviewed the initial symptoms, characteristics, treatments, and disease course of 37 patients (45 limbs) with TAO. Logistic regression analysis was performed to investigate factors affecting the course of symptoms that persisted or worsened despite treatment. Results: Patients' mean age was 37.2±11.4 years, and all patients were men. The mortality rate was 0% during the follow-up period (76.9±51.1 months). All patients were smokers at the time of diagnosis, and 19 patients (51.4%) successfully quit smoking during treatment. When comparing the Rutherford categories before and after treatment, 23 limbs (51.1%) showed improvement, the category was maintained in 11 limbs (24.4%), and 11 limbs (24.4%) worsened. Symptom persistence or exacerbation despite treatment was associated with a higher initial Rutherford category (odds ratio [OR], 1.59; 95% confidence interval [CI], 1.04-2.42; p=0.03) and a higher score of the involved below-knee artery at the time of diagnosis (OR, 2.26; 95% CI, 1.10-4.67; p=0.03). Conclusion: The degree of disease progression at the time of diagnosis significantly affected patients' prognosis. Therefore, early diagnosis and intervention are important to improve the course of TAO.

Prospective multicenter study of a novel endovascular venous anastomotic procedure and device for implantation of an arteriovenous graft for hemodialysis.

INTRODUCTION: The traditional sutured venous anastomosis used during arteriovenous graft implantation is associated with a high incidence of subsequent stenosis that is attributed to neointimal hyperplasia. Hyperplasia results from multiple factors, including hemodynamic abnormalities and vessel trauma during implantation. A novel anastomotic connector device was designed to provide an alternative, less traumatic, endovascular venous anastomosis that may ameliorate the clinical challenges associated with a sutured anastomosis. A prospective single-arm multicenter study was performed to evaluate safety and effectiveness of graft implantation using the study device. METHODS: Patients requiring graft creation and who met the study criteria were enrolled between February 2018 and July 2021 and observed for 6 months. Collected data included baseline characteristics, graft patency and use for hemodialysis, graft interventions, and adverse events. The primary study endpoint was cumulative graft patency, compared to a pre-specified Performance Goal of 75%. Secondary endpoints included primary unassisted patency and serious adverse events, defined as the occurrence of death, graft infection, emergent surgery, significant bleeding, and pseudoaneurysm. RESULTS: A total of 158 patients were enrolled from 10 study sites, among which 144 subjects were evaluable at 6 months and 14 were censored with partial follow-up observation. Three patients died and the graft was abandoned in 12. The primary endpoint was met (p-value < 0.001). By Kaplan Meier survival analysis, cumulative patency was 92.08% with a lower 95% Confidence Bound of 86.98%. Primary unassisted patency was 60.21% with a lower 95% Confidence Bound of 50.84%. Graft infections occurred in six patients, all unrelated to the study device. There were no reports of emergent surgery, significant bleeding or pseudoaneurysm. CONCLUSION: These results demonstrate that the study device can be used for successful endovascular anastomosis of a vein to a graft for hemodialysis, with acceptable cumulative patency and safety profile at 6 months. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02532621.

Nefroprotección en frío para reparo de ectasia aórtica y aneurismas ilíacos bilaterales ante la presencia de riñón ectópico pélvico / Cold nephroprotection for repair of aortic ectasia and bilateral iliac aneurysms in the presence of pelvic ectopic kidney

Resumen Los riñones ectópicos pélvicos solitarios asociados a degeneración aneurismática de las arterias ilíacas y la aorta abdominal son eventos muy raros. Los enfoques quirúrgicos para la corrección de aneurismas con compromiso renal son un desafío por la falta de consenso actual, en especial cuando cursan con riñones ectópicos pélvicos solitarios funcionales asociados. Por tal motivo, una de las estrategias que ha demostrado buenos resultados a corto y mediano plazo es la nefroprotección en frío, la cual puede ser usada con seguridad en estos pacientes. En el caso que se presenta, se evidenció una ectasia aórtica con aneurismas ilíacos bilaterales asociados con un riñón ectópico pélvico solitario en un paciente masculino de 75 años, con hipertensión arterial y dislipidemia. Se realizó una reconstrucción aortoilíaca bilateral y una reconstrucción de la arteria hipogástrica, además de reimplante de la arteria renal ectópica bajo irrigación renal en frío, sin complicaciones y preservación de la función renal.

Abstract Solitary pelvic ectopic kidneys associated with aneurysmal degeneration of the iliac arteries and abdominal aorta are very rare events. Surgical approaches for the correction of aneurysms with renal involvement are challenging due to the lack of current consensus, especially when they are associated with functional solitary pelvic ectopic kidneys. For this reason, one of the strategies that has shown good results in the short and medium term is cold nephroprotection, which can be used safely in these patients. In the present case, aortic ectasia with bilateral iliac aneurysms associated with a solitary pelvic ectopic kidneys was evidenced in a 75-year-old male patient with arterial hypertension and dyslipidemia. Bilateral aortoiliac reconstruction was performed with hypogastric artery reconstruction and reimplantation of the ectopic renal artery under cold renal irrigation, without complications and preservation of renal function.

Influence of crural vessel run-off on short- and mid-term outcomes following femoro-popliteal bypass grafting.

OBJECTIVES: To determine the influence that the number of patent crural run-off vessels has on short- and mid-term outcomes following femoro-popliteal bypass. METHODS: All patients undergoing index femoro-popliteal bypass grafting between 2013 and 19 at our unit were included. Preoperative imaging was used to stratify patients into cohorts with either one or ≥2 patent run-off vessels. Primary outcomes measures included bypass patency and limb salvage rates at one and 3 years post-operatively. Survival analysis was performed using Kaplan-Meier curves and Logrank test. RESULTS: 147 bypasses performed on 143 patients were included. 24 patients had one-vessel run-off and 123 had ≥2 vessels patent. Patients with one-vessel run-off had a higher proportion of emergency admissions (54% vs 41%) and diabetes (42% vs 31%). 31% of patients underwent diagnostic angiogram imaging in addition to having duplex ultrasound and/or computed tomography angiography. There were no significant differences in primary, primary-assisted or secondary patency rates between the cohorts at 12 or 36 months. Limb salvage rates were significantly higher amongst those with ≥2 vessel run-off at 12 (86% vs 71%, p = 0.03) and 36 (85% vs 71%, p = 0.04) months. For those with occluded grafts, a higher proportion of patients with ≥2 vessel run-off subsequently had an attempt at redo bypass grafting. CONCLUSIONS: Femoro-popliteal bypass is a reasonable treatment option for patients with one-vessel run-off. However, whilst patency rates are comparable, clinicians should be aware of the lower successful limb salvage rates for patients with one patent vessel (especially those presenting with tissue loss).

Microvascularized Fibular Bone Grafting for the Treatment of Mandibular Expansive Osseous Dysplasia - A Case Report.

Rationale: Osseous dysplasia (OD) is a benign fibro-osseous lesion classified as periapical, focal or florid with some rare cases being diagnosed as expansive OD. Patient Concerns: A 43-year-old female presented with gross mandible expansion and tooth displacement. Diagnosis: Imaging scans revealed an expansive lesion in the anterior mandible, with varying opacity in the central region, and other smaller lesions in the region of teeth #37 and #47, consistent with expansive OD. Treatment: Surgical resection followed by immediate reconstruction of the mandibular defect using a microvascularized fibular graft. Outcomes: The patient had a 4-year follow-up, with adequate mandibular bone continuity, mastication, swallowing, and speaking ability reestablished. Take-away Lessons: Immediate reconstruction after large surgical resection is required as tissues retract over time, hampering late reconstructions. Microvascularized fibular graft aims at adequate and functional rehabilitation with osseointegrated implants and long-term follow-up is needed as florid OD may evolve into expansive OD.

Treatment options for dialysis access steal syndrome.

Vascular access-induced limb ischemia is a known complication of arteriovenous fistulas and grafts. Many techniques have been adopted to prevent steal in high-risk patients and to treat steal in cases of moderate ischemia not controlled with conservative management. A major factor guiding treatment is access flow volume. Management is different when ischemia is combined with the excessive flow in contrast to the combination with normal flow. We describe the most popular techniques encountered in the English literature as a part of a stepwise approach to treating dialysis access steal syndrome. In absence of ischemia, when cardiac issues emerge due to extreme access flow volumes, some of these techniques are also used to decrease flow and protect the heart. Patient's history, focused clinical examination, color duplex ultrasound examination, pulse oximetry and an angiogram are essential tools to approach this entity.

First Robotic Hepatectomy With Middle Hepatic Vein Reconstruction Using ePTFE Graft for Hepatic Adenoma: A Case Report.

Surgical resection remains the best choice for the treatment of liver tumors. Hepatectomy combined with artificial vascular reconstruction has been proven as an alternative to treating tumors involving the main hepatic veins. As the cutting-edge surgical technique, robotic liver surgery is a novel procedure expanding the field of minimally invasive approaches, especially in complex reconstruction. This study reports, for the first time, on a robotic hepatectomy with middle hepatic vein (MHV) reconstruction using an expanded polytetrafluoroethylene (ePTFE) graft for a patient with hepatic adenoma. The tumor, which was located in segment 8, was adjacent to the MHV. Robot-assisted resection of segment 4 and partial segment 8, and MHV reconstruction using a ePTFE graft were performed. During the post-operative examination and follow-up, the blood flow of the ePTFE graft was patent, and liver function recovered well. Thus, robotic hepatectomy with MHV reconstruction is a safe, minimally invasive, and precise surgery that may provide a novel approach for patients with liver tumors that are invading or adjacent to the main hepatic veins.

Subclavian-Brachial Bypass for Chronic Limb Threatening Ischemia Associated with an Old Motorcycle Accident.

Chronic limb-threatening ischemia is rarely associated with previous traumatic injury. We present a case of a 28-year-old male with progressive digit ulcers, a weak pulse, cyanosis, and a cold limb. Eight months prior, he had a motorcycle accident resulting in a right clavicle fracture and brachial plexus injury. Computed tomography angiography revealed occlusion of the right subclavian artery near a surgically implanted reduction plate. The patient underwent an open subclavian-brachial bypass with a reversed saphenous vein graft. His postoperative recovery was uneventful. After 3 months, he had a euthermic right hand with a palpable pulse and his ulcers had completely healed. This case reinforces the need for patients with a neurological deficit in the upper extremity caused by blunt trauma to undergo thorough vascular examination to identify potential arterial injury and compromised perfusion.

Vascular grafts collagen coating resorption and healing process in humans.

Background: The objective of the present study was to evaluate the bioresorption rate of collagen coating (CC) sealed on textile vascular grafts (VGs) and their healing in humans using histologic analysis of explanted VGs. Methods: A total of 27 polyester textile VGs had been removed during surgery from 2012 to 2020. The segments underwent histologic assessment. The CC bioresorption rate was assessed using morphometric analysis to determine the internal and external capsule thickness, inflammatory reaction degree, presence of neovessels, and endothelial cell layer. Results: A total of 27 VGs were explanted from 25 patients because of infection (n = 5; 18.5%), thrombosis (n = 7; 25.9%), stenosis (n = 2; 7.4%), rupture (n = 4; 14.8%), aneurysmal degeneration (n = 3; 11.1%), revascularization (n = 4; 14.8%), or another cause (n = 2; 7.4%), with a median implantation duration of 291 days (interquartile range [IQR], 48-911 days). VGs with remaining CC (n = 7; 26%) had been explanted earlier than had those without (n = 20; 74%; 1 day [IQR, 1-45 days] vs 516 days [IQR, 79-2018 days]; P = .001). After 1 year, no remaining CC was detected on the analyzed VG sections. VGs implanted for <90 days had had a greater CC maximal thickness (63.90 µm [IQR, 0-83.25 µm] vs 0 µm [IQR, 0-0 µm]; P = .006) and a greater CC surface coverage (180° [IQR, 0°-360°] vs 0° [IQR, 0°-0°]; P = .002) than those implanted for >90 days. VGs implanted for >90 days had a greater external capsule thickness (889.2 µm [IQR, 39.6-1317 µm] vs 0 µm [IQR, 0-0 µm]; P = .002), a higher number of inflammatory mononuclear cells and giant cells (168 cells [IQR, 110-310 cells] vs 0 cells [IQR, 0-94 cells]; P < .0001) and a higher number of neovessels (4 [IQR, 0-5] vs 0 [IQR, 0-0]; P = .001) than those implanted for <90 days. Conclusions: CC had a slow bioresorption rate in humans. Complete healing was never achieved, with no endothelial coverage observed. This finding implies that CC might not help graft healing.

Leriche Syndrome with Digital Gangrene: Is Aortic Bypass Grafting Safe in Intravenous Drug Abusers? A Case Report and Literature Review.

A 47-year-old male with Leriche syndrome presented with digital gangrene due to TASC II type-D occlusion of the distal aorta and common iliac arteries. Open revascularization was performed using a Dacron aorto-biiliac bypass graft; however, the postoperative course revealed a nondisclosed history of intravenous opioid abuse as he went into withdrawal psychosis. Our report highlights ways to mitigate infection risk associated with prosthetic aortic grafts in suspected or confirmed intravenous drug abusers. The literature review suggests alternative strategies like aortoiliac endarterectomy, total endovascular approach using non-covered stents, or a hybrid approach. The primary use of autologous venous grafts should be considered as a last resort so that the veins are retained for future use in case of graft infection. Patient factors like comorbidities, fitness to undergo surgery, anatomical extent of occlusion, and availability of facilities/expertise can further guide the management plan owing to a lack of evidence-based guidelines.