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No alternative tissue-engineered vascular grafts for the abdominal venous system are reported. The present study focused on the development of new tissue-engineered vascular graft using a silk-based scaffold material for abdominal venous system replacement. A rat vein, the inferior vena cava, was replaced by a silk fibroin (SF, a biocompatible natural insoluble protein present in silk thread), tissue-engineered vascular graft (10 mm long, 3 mm diameter, n = 19, SF group). The 1 and 4 -week patency rates and histologic reactions were compared with those of expanded polytetrafluoroethylene vascular grafts (n = 10, ePTFE group). The patency rate at 1 and 4 weeks after replacement in the SF group was 100.0% and 94.7%, and that in the ePTFE group was 100.0% and 80.0%, respectively. There was no significant difference between groups ( p  = 0.36). Unlike the ePTFE graft, CD31-positive endothelial cells covered the whole luminal surface of the SF vascular graft at 4 weeks, indicating better endothelialization. SF vascular grafts may be a promising tissue-engineered scaffold material for abdominal venous system replacement.

Venous reconstruction has been recently demonstrated to be safe for tumours with invasion into portal vein and/or superior mesenteric vein. This study aims to compare the patency between various venous reconstructions. This is retrospective study of 76 patients who underwent pancreaticoduodenectomy or total pancreatectomy with venous reconstruction from 2006 to 2018. Patient demographics, tumour histopathology, morbidity, mortality and patency were studied. Kaplan-Meier estimates were performed for primary venous patency. Sixty-two patients underwent pancreaticoduodenectomy and 14 underwent total pancreatectomy. Forty-seven, 19 and 10 patients underwent primary repair, end-to-end anastomosis and interposition graft respectively. Major morbidity (Clavien-Dindo >grade 2) and 30-day mortality were 14/76(18.4%) and 1/76(1.3%) respectively. There were 12(15.8%) venous occlusion including 4(5.3%) acute occlusions. Overall 6-month, 1-year and 2-year primary patency was 89.1%, 92.5% and 92.3% respectively. 1-year primary patency of primary repair was superior to end-to-end anastomosis and interposition graft (primary repair 100%, end-to-end anastomosis 81.8%, interposition graft 66.7%, p = 0.045). Pairwise comparison also demonstrated superior 1-year patency of primary repair (adjusted p = 0.037). There was no significant difference between the cumulative venous patency for each venous reconstruction method: primary repair 84±6%, end-to-end anastomosis 75±11% and interposition graft 76±15% (p = 0.561). 1-year primary venous patency of primary repair is superior to end-to-end anastomosis and interposition graft.

The aim of this study was to identify anatomical and clinical factors associated with limb-based patency (LBP) loss, major adverse limb events (MALEs), and poor amputation-free survival (AFS) after an infrapopliteal arterial bypass (IAB) surgery according to the Global Limb Anatomic Staging System. A retrospective analysis of patients undergoing IAB surgery between January 2010 and December 2021 at a single institution was performed. Two-year AFS, freedom from LBP loss, and freedom from MALEs were assessed using the Kaplan–Meier method. Anatomical and clinical predictors were assessed using multivariate analysis. The total number of risk factors was used to calculate risk scores for subsequent categorization into low-, moderate-, and high-risk groups. IABs were performed on 103 patients. The rates of two-year freedom from LBP loss, freedom from MALEs, and AFS were 71.3%, 76.1%, and 77.0%, respectively. The multivariate analysis showed that poor run-off beyond the ankle and a bypass vein caliber of < 3 mm were significantly associated with LBP loss and MALEs. Moreover, end-stage renal disease, non-ambulatory status, and a body mass index of < 18.5 were significantly associated with poor AFS. The rates of freedom from LBP loss and MALEs and the AFS rate were significantly lower in the high-risk group than in the other two groups (12-month low-risk rates: 92.2%, 94.8%, and 94.4%, respectively; 12-month moderate-risk rates: 58.6%, 84.6%, and 78.3%, respectively; 12-month high-risk rates: 11.1%, 17.6%, and 56.2%, respectively; p  < 0.001, p  < 0.001, and p  < 0.001, respectively). IAB is associated with poor clinical outcomes in terms of LBP, MALEs, and AFS in high-risk patients. Risk stratification based on these predictors is useful for long-term prognosis.

We aimed to compare the clinical outcomes between endovascular treatment and inframalleolar bypass surgery for critical limb ischemia (CLI) in patients with thromboangiitis obliterans (TAO) and to assess the role of bypass surgery in the era of innovative endovascular treatment. Between January 2007 and December 2017, a total of 33 consecutive patients with the diagnosis of TAO presenting with CLI who underwent endovascular treatment (endovascular group, n = 22) or bypass surgery to the pedal or plantar vessels (bypass group, n = 11) were included and analyzed retrospectively. The primary endpoint was defined as a major amputation of the index limb, and the secondary endpoint was defined as graft occlusion, regardless of the number of subsequent procedures. In the bypass group, six patients (55%) had undergone previous failed endovascular procedures and/or arterial bypass surgery to the index limb before inframalleolar bypass, and two patients (18%) received microvascular flap reconstruction after bypass surgery. During the median follow-up period of 32 months (range 1-115 months), there were no significant differences in primary and secondary endpoints between the two groups although the bypass group had a higher Rutherford class than the endovascular group. Kaplan-Meier survival analysis showed that there were similar limb salvage (P = 0.95) and graft patency rates (P = 0.39). In conclusion, endovascular treatment is a valid strategy leading to an acceptable limb salvage rate for TAO patients, and surgical bypass to distal target vessels could play a vital role in cases of previous failed endovascular treatment or extensive soft tissue loss of the foot.

Background Acute Stanford type A aortic dissection (TAAD) is a life-threatening condition. Surgery is usually performed as a salvage procedure and is associated with significant postoperative early mortality and morbidity. Understanding the patient’s conditions and treatment strategies which are associated with these adverse events is essential for an appropriate management of acute TAAD. Methods Nineteen centers of cardiac surgery from seven European countries have collaborated to create a multicentre observational registry (ERTAAD), which will enroll consecutive patients who underwent surgery for acute TAAD from January 2005 to March 2021. Analysis of the impact of patient’s comorbidities, conditions at referral, surgical strategies and perioperative treatment on the early and late adverse events will be performed. The investigators have developed a classification of the urgency of the procedure based on the severity of preoperative hemodynamic conditions and malperfusion secondary to acute TAAD. The primary clinical outcomes will be in-hospital mortality, late mortality and reoperations on the aorta. Secondary outcomes will be stroke, acute kidney injury, surgical site infection, reoperation for bleeding, blood transfusion and length of stay in the intensive care unit. Discussion The analysis of this multicentre registry will allow conclusive results on the prognostic importance of critical preoperative conditions and the value of different treatment strategies to reduce the risk of early adverse events after surgery for acute TAAD. This registry is expected to provide insights into the long-term durability of different strategies of surgical repair for TAAD. Trial registration ClinicalTrials.gov Identifier: NCT04831073 .

The control of nanofiber orientation in nanofibrous tubular scaffolds can benefit the cell responses along specific directions. For small diameter tubular scaffolds, however, it becomes difficult to engineer nanofiber orientation. This paper reports a novel electrospinning technique for the fabrication of 3-D nanofibrous tubular scaffolds with controllable nanofiber orientations. Synthetic absorbable poly-ε-caprolactone (PCL) was used as the model biomaterial to demonstrate this new electrospinning technique. Electrospun 3-D PCL nanofibrous tubular scaffolds of 4.5 mm in diameter with different nanofiber orientations (viz. circumferential, axial, and combinations of circumferential and axial directions) were successfully fabricated. The degree of nanofiber alignment in the electrospun 3-D tubular scaffolds was quantified by using the fast Fourier transform (FFT) analysis. The results indicated that excellent circumferential nanofiber alignment could be achieved in the 3-D nanofibrous PCL tubular scaffolds. The nanofibrous tubular scaffolds with oriented nanofibers had not only directional mechanical property but also could facilitate the orientation of the endothelial cell attachment on the fibers. Multiple layers of aligned nanofibers in different orientations can produce 3-D nanofibrous tubular scaffolds of different macroscopic properties.

Background Evolution of thoracic endovascular aortic repair (TEVAR) appears to have influenced the pathogenesis and treatment strategy for aortoesophageal fistula (AEF). The purposes of this study are to evaluate our current surgical strategy for AEF and to provide insight to further improve the prognosis of such a devastating condition. Methods and results Between 2005 and 2013, we retrospectively reviewed the clinical charts of 10 patients requiring surgical treatment for AEF in Tohoku University Hospital. Four cases were primary and 6 were secondary. Initially, bridging TEVAR to control bleeding with concomitant subtotal esophagectomy and complete debridement of infected mediastinal tissue was performed. After a short interval, the patients underwent in situ aortic replacement with cryopreserved homografts or rifampicin-bonded Dacron grafts with omentopexy. Esophageal reconstruction was planned following general physical status improvement after 3–6 months. In-hospital mortality in the acute phase was 30 %. Although the completion of the staged strategy achieving successful esophageal reconstruction was possible in 5 patients, no local relapses of infection were observed in these patients. Overall survival at 1 and 5 year were 68.6 and 42.9 %, respectively. Conclusions The staged surgical treatment strategy for AEF consisted of prompt TEVAR to control bleeding with concomitant subtotal esophagectomy and subsequent in situ reconstruction of the aorta with an aortic homograft. This procedure enabled us to control local mediastinal infection with acceptable mortality. Avoiding delay in the diagnosis and initial treatment and resolving complications at each treatment step should further improve AEF treatment.

Surgical approach to type A acute aortic dissection (AADA) is usually dictated by the presenting anatomy. We compared long-term outcomes of AADA repaired with a root replacement versus a supracoronary tube graft, regardless of the proximal extent of the intimal tear. A single-centre, retrospective cohort of consecutive patients undergoing repair of AADA between December 1999 and March 2012 were stratified based on the proximal surgical procedure performed: supracoronary tube graft or root replacement. Imaging, chart reviews and clinical follow-ups were analyzed to identify the presenting anatomy and clinical outcomes. We included the cases of 75 patients in our analysis: 54 received a supracoronary tube graft and 21 received a root replacement. The proximal tear was identified below the sinotubular junction in all patients in the root group and in 61% of patients in the supracoronary group. We detected no differences between the groups for in-hospital mortality, length of stay, or complications. However, the root group had significantly increased renal failure (0% v. 9.5%, p = 0.018), cardiopulmonary bypass time (198.4±80.0 min v. 316.5±102.5 min, p < 0.001), cross-clamp time (91.6±34.9 min v. 191.3±52.8 min, p < 0.001), duration of surgery (457.5±129.9 min v. 611.6±197.8 min, p < 0.001), and platelet transfusions (8.1±7.6 v. 12.8±8.7 units, p = 0.021) than the supracoronary group. Long-term follow-up demonstrated a greater incidence of 2+ aortic regurgitation among patients in the supracoronary group than the root group (29.7% v. 0.0%, p = 0.006); however, there was no difference between the groups in symptoms or reoperation. In AADA, aortic root replacement involves a longer procedure with increased risk of early renal impairment. Long-term follow-up identified significantly more aortic regurgitation and root dilation in the supracoronary group than the root group, with a trend toward worse long-term survival. However, we found no difference between the groups in mortality, reoperation or New York Heart Association class. L’approche chirurgicale à la dissection aigüe de l’aorte de type A (DAAA) dépend habituellement de la présentation anatomique. Nous avons comparé les résultats à long terme d’une DAAA réparée par remplacement de la racine de l’aorte c. greffon supracoronarien artificiel, indépendamment de la portée proximale de la déchirure de l’intima. Une cohorte rétrospective monocentrique de patients consécutifs soumis à une réparation de DAAA entre décembre 1999 et mars 2012 a été stratifiée en fonction de l’intervention chirurgicale proximale effectuée : greffon supracoronarien artificiel ou remplacement de la racine de l’aorte. Les épreuves d’imagerie, résumés de dossiers et suivis cliniques ont été analysés pour cerner la présentation anatomique et les résultats cliniques. Nous avons inclus 75 patients dans notre analyse : 54 ont reçu un greffon supracoronarien artificiel et 21 ont subi un remplacement de la racine de l’aorte. Une déchirure proximale a été identifiée sous la jonction sinotubulaire chez tous les patients du groupe racine de l’aorte et chez 61 % des patients du groupe greffon supracoronarien. Nous n’avons décelé aucune différence entre les groupes pour ce qui est de la mortalité en milieu hospitalier, de la durée de l’hospitalisation ou des complications. Mais, le groupe racine de l’aorte a présenté des augmentations significatives du nombre de cas d’insuffisance rénale (0 % c. 9,5 %, p = 0,018), de la durée de la circulation extracorporelle (198,4 ± 80,0 min c. 316,5 ± 102,5 min, p < 0,001), du clampage de l’aorte (91,6 ± 34,9 min c. 191,3 ± 52,8 min, p < 0,001) et de la chirurgie (457,5 ± 129,9 min c. 611,6 ± 197,8 min, p < 0,001), ainsi que du nombre de transfusions plaquettaires (8,1 ± 7,6 unités c. 12,8 ± 8,7 unités, p = 0,021) comparativement au groupe greffon supracoronarien. Le suivi à long terme a fait état d’une incidence plus élevée de régurgitation aortique 2+ chez les patients du groupe greffon supracoronarien comparativement au groupe racine de l’aorte (29,7 % c. 0,0 %, p = 0,006); toutefois, on n’a noté aucune différence entre les groupes pour ce qui est des symptômes ou du taux de réopération. Dans la DAAA, le remplacement de la racine de l’aorte suppose une intervention de plus longue durée qui s’accompagne d’un risque accru d’insuffisance rénale précoce. Un suivi à long terme a révélé un nombre significativement plus élevé de cas de régurgitation aortique et de dilatation de la racine de l’aorte dans le groupe greffon supracoronarien que dans le groupe racine de l’aorte, avec une tendance moins favorable au plan de la survie à long terme. Toutefois, nous n’avons trouvé aucune différence entre les groupes pour ce qui est de la mortalité, du taux de réopération ou de la classe de la New York Heart Association.

Neointimal hyperplasia (NIH) in bypass conduits such as veins and prosthetic grafts is an important clinical entity that limits the long-term success of vascular interventions. Although the development of NIH in the conduits shares many of the same features of NIH that develops in native arteries after injury, vascular grafts are exposed to unique circumstances that predispose them to NIH, including surgical trauma related to vein handling, hemodynamic changes creating areas of low flow, and differences in biocompatibility between the conduit and the host environment. Multiple different approaches, including novel surgical techniques and targeted gene therapies, have been developed to target and prevent the causes of NIH. Recently, the PREVENT trials, the first molecular biology trials in vascular surgery aimed at preventing NIH, have failed to produce improved clinical outcomes, highlighting the incomplete knowledge of the pathways leading to NIH in vascular grafts. In this review, we aim to summarize the pathophysiologic pathways that underlie the formation of NIH in both vein and synthetic grafts and discuss current and potential mechanical and molecular approaches under investigation that may limit NIH in vascular grafts.

We have developed a new biodegradable scaffold that does not require any cell seeding to create an in-situ tissue-engineering vasculature (iTEV). Animal experiments were conducted to test its characteristics and long-term efficacy. An 8-mm tubular biodegradable scaffold, consisting of polyglycolide knitted fibers and an L-lactide and ε-caprolactone copolymer sponge with outer glycolide and ε-caprolactone copolymer monofilament reinforcement, was implanted into the inferior vena cava (IVC) of 13 canines. All the animals remained alive without any major complications until euthanasia. The utility of the iTEV was evaluated from 1 to 24 months postoperatively. The elastic modulus of the iTEV determined by an intravascular ultrasound imaging system was about 90% of the native IVC after 1 month. Angiography of the iTEV after 2 years showed a well-formed vasculature without marked stenosis or thrombosis with a mean pressure gradient of 0.51 ± 0.19 mmHg. The length of the iTEV at 2 years had increased by 0.48 ± 0.15 cm compared with the length of the original scaffold (2-3 cm). Histological examinations revealed a well-formed vessel-like vasculature without calcification. Biochemical analyses showed no significant differences in the hydroxyproline, elastin, and calcium contents compared with the native IVC. We concluded that the findings shown above provide direct evidence that the new scaffold can be useful for cell-free tissue-engineering of vasculature. The long-term results revealed that the iTEV was of good quality and had adapted its shape to the needs of the living body. Therefore, this scaffold would be applicable for pediatric cardiovascular surgery involving biocompatible materials.