Vaso-Lock for sutureless anastomosis in a pig arteriovenous loop model.

A vascular anastomosis is a critical surgical skill that involves connecting blood vessels. Traditional handsewn techniques can be challenging and resource intensive. To address these issues, we have developed a unique sutureless anastomotic device called Vaso-Lock. This intraluminal device connects free vascular ends using anchors to maintain traction and enable a rapid anastomosis. We tested the anastomotic capability of Vaso-Locks in a pig common carotid-internal jugular arteriovenous model. The use of Vaso-Lock allowed us to accomplish this procedure in less than 10 min, in contrast to the approximately 40 min required for a handsewn anastomosis. The Vaso-Lock effectively maintained patency for at least 6 weeks without causing significant tissue damage. Histological analysis revealed that the device was successfully incorporated into the arterial wall, promoting a natural healing process. Additionally, organ evaluations indicated no adverse effects from using the Vaso-Lock. Our findings support the safety and effectiveness of the Vaso-Lock for arteriovenous anastomosis in pigs, with potential applicability for translation to humans. Our novel sutureless device has the potential to advance surgical practice and improve patient outcomes.

Tailoring of arteriovenous graft-to-vein anastomosis angle to attenuate pathological flow fields.

Arteriovenous grafts are routinely placed to facilitate hemodialysis in patients with end stage renal disease. These grafts are conduits between higher pressure arteries and lower pressure veins. The connection on the vein end of the graft, known as the graft-to-vein anastomosis, fails frequently and chronically due to high rates of stenosis and thrombosis. These failures are widely believed to be associated with pathologically high and low flow shear strain rates at the graft-to-vein anastomosis. We hypothesized that consistent with pipe flow dynamics and prior work exploring vein-to-artery anastomosis angles in arteriovenous fistulas, altering the graft-to-vein anastomosis angle can reduce the incidence of pathological shear rate fields. We tested this via computational fluid dynamic simulations of idealized arteriovenous grafts, using the Bird-Carreau constitutive law for blood. We observed that low graft-to-vein anastomosis angles ([Formula: see text]) led to increased incidence of pathologically low shear rates, and that high graft-to-vein anastomosis angles ([Formula: see text]) led to increased incidence of pathologically high shear rates. Optimizations predicted that an intermediate  ([Formula: see text]) graft-to-anastomosis angle was optimal. Our study demonstrates that graft-to-vein anastomosis angles can significantly impact pathological flow fields, and can be optimized to substantially improve arteriovenous graft patency rates.

Study of the placental characteristics and time of onset of twin-to-twin transfusion syndrome.

INTRODUCTION: To investigate the correlation between placental superficial anastomoses, placental territory and the umbilical cord attachment site with the time of onset of twin-to-twin transfusion syndrome (TTTS), and to explore the influence of placental characteristics on the time of onset of TTTS. METHODS: A retrospective analysis was performed on 48 cases of TTTS managed conservatively at the Obstetrics Department of Peking University Third Hospital from April 2014 to April 2019. Placental superficial anastomoses, placental territory, the distance between the insertion points of the umbilical cord were measured after placental dye injection. Correlation analysis was conducted between placental characteristics and the time of onset of TTTS. RESULTS: (1) The incidence of AA anastomoses was 33.3% (16/48) with a mean total diameter of 2.3 ± 1.4 mm, that of AV anastomoses was 95.8% (46/48) with a mean total diameter of 1.2 ± 0.4 mm, and that of VV anastomoses 22.9% (11/48) with a mean total diameter of 2.3 ± 1.1 mm (2) The time of onset of TTTS was positively correlated with the umbilical insertion ratio (Spearman correlation coefficient = 0.404, P = 0.004), but not correlated with the total diameter of anastomoses in the three different types, or with placental territory discordance. DISCUSSION: The time of onset of TTTS was positively correlated with the umbilical insertion ratio, which suggest that the distance between umbilical cord insertion sites may affect the time of onset of TTTS. The smaller the distance between the umbilical cord insertion sites, the earlier the time of onset of TTTS is likely to be.

Endovascular management of dissecting posterior cerebral artery aneurysm associated with persistent hypoglossal artery: A case report / Tratamento endovascular do aneurisma dissecante da artéria cerebral posterior associado à artéria hipoglossa persistente: relato de caso

Abstract Persistent embryological connections between the anterior and posterior circulations are rare entities. Persistent hypoglossal artery is the second most common persistent carotid-basilar anastomosis. As it is often associated with hypoplasia of vertebral arteries, it poses a challenge during endovascular interventions. We present a case of a 32-year-old woman who presented with occipital headache of four weeks' duration. Magnetic Resonance Angiography showed hypoplastic vertebral arteries with a persistent hypoglossal artery arising from the cervical segment of the left internal carotid artery and supplying the entire posterior circulation, associated with a dissecting aneurysm of the right posterior cerebral artery. Endovascular parent vessel occlusion was performed for the dissecting posterior cerebral artery aneurysm by navigating the guide catheter, microwire, and microcatheter through the persistent hypoglossal artery because the vertebral arteries were hypoplastic. Post-intervention, the patient did not develop any neurological deficit and was discharged in a stable condition.

Resumo Conexões embriológicas persistentes entre as circulações anterior e posterior são entidades raras. A artéria hipoglossa persistente é a segunda anastomose carotídeo-basilar persistente mais comum. Como está frequentemente associada à hipoplasia das artérias vertebrais, apresenta um desafio durante as intervenções endovasculares. Apresentamos o caso de uma mulher de 32 anos que apresentou cefaleia occipital com duração de quatro semanas. A angiografia por ressonância magnética mostrou artérias vertebrais hipoplásicas com artéria hipoglossa persistente surgindo do segmento cervical da artéria carótida interna esquerda e suprindo toda a circulação posterior com um aneurisma dissecante da artéria cerebral posterior direita. A oclusão endovascular do vaso parental foi realizada para o aneurisma da dissecção da artéria cerebral posterior pela passagem de cateter guia, microfio e microcateter pela artéria hipoglossa persistente, pois as artérias vertebrais eram hipoplásicas. Após a intervenção, a paciente não apresentou déficit neurológico e recebeu alta em uma condição estável.

Wound closure by means of free flap and arteriovenous loop: Development of flap autonomy in the long-term follow-up.

Free flaps in combination with arterial reconstruction by means of arteriovenous loops or bypass have, meanwhile, been established as a therapeutic option in defect reconstruction for areas without recipient vessels. Our aim was to analyse the long-term performance, flap autonomy, and the flap perfusion. Patients receiving this combined reconstruction at a single-centre institution were included. During follow-up examination, the patency of arterial reconstruction was investigated by duplex ultrasound. Flap micro-circulation was assessed by laser Doppler flowmetry and white light tissue spectrometry (O2C) as well as by indocyanine green fluorescence angiography. Twenty-three patients could be clinically followed up. Duplex ultrasound showed, in four cases, arterial pedicle occlusion in spite of vital flap. Comparison of the O2C perfusion parameters between flaps with occluded pedicles and those with intact inflow showed no significant difference (parameters sO2: P = .82; Flow: P = .31). Similar results were obtained by fluorescence angiography; no significant difference could be detected between both groups (parameters Ingress P = .13; Ingressrate P = .54). Combined vascular reconstruction with free tissue transfer is associated with a good long-term outcome and wound closure. Even after flap transplantation to areas with critical tissue perfusion, the flap can develop autonomy and thus survive after pedicle occlusion.

Vascular suture line wrapping for Aortoiliac anastomoses following open surgical repair of Infrarenal Behçet's Aortoiliac aneurysms.

BACKGROUND: This study was conducted to evaluate our local experiences of adjunctive mechanical prosthetic wrapping for aortoiliac vascular anastomoses as a prophylactic measure following surgical repair of Behçet's aortoiliac aneurysms. The goal of prosthetic wrapping to reinforce the vascular anastomoses by mechanical protection to reduce the bleeding complications, and consequently pseudoaneurysm formation. This was aided by the administration of pre- and postoperative immunosuppressive therapy as an adjuvant treatment. METHODS: A seven-year retrospective study was conducted between January 2006 and December 2012, retrieving data of patients with Behçet's aortoiliac aneurysms. All patients underwent open surgical repair using a heparin-bonded synthetic Dacron® graft. Data for all patients were retrieved and analyzed for diagnostic procedures, graft selection, as well as, different methods of surgical repair. Graft-related complications such as anastomotic pseudoaneurysms, occlusion, and thrombosis were also reported. RESULTS: Sixteen patients were recruited in this study. There were  11 (69%) males and 5 (31%) females with the male to female ratio 2:1. The patients' age ranged between 25 and 47 years with the mean of 36.4 ± 7.3. All Behçet's aortic/aortoiliac aneurysms were repaired by the application of heparin-bonded Dacron® tube and bifurcated grafts. The anastomotic wrapping technique was performed for both the proximal and the distal vascular anastomoses. The technical success of aortoiliac aneurysm and wrapping techniques was achieved in 100% of patients. All patients were given pre- and postoperative systemic immunosuppressive therapy. No graft-related complications were reported except for only one anastomotic pseudoaneurysm that developed at one of the right iliac anastomoses, that developed within 24 months after follow up. CONCLUSIONS: Mechanical prosthetic wrapping for vascular anastomoses in patients with Behçet's aortic/aortoiliac aneurysms is a feasible, simple, and reliable technique with low morbidity and mortality. It was performed as a prophylactic measure to avoid the development of postoperative anastomotic pseudoaneurysms. It must be performed for all patients with Behçet's arterial aneurysms whenever possible. Furthermore, the supplemental administration of pre- and postoperative systemic immunosuppressive therapy should be considered as an important factor for the prophylaxis and prevention of anastomotic pseudoaneurysms and other graft-related complications.

Novel rodent model for simulation of sylvian fissure dissection and cerebrovascular bypass under subarachnoid hemorrhage conditions: technical note and timing study.

OBJECTIVESylvian fissure dissection following subarachnoid hemorrhage (SAH) is a challenging but fundamental skill in microneurosurgery, and one that has become increasingly difficult to develop during residency, given the overarching management trends. The authors describe a novel rodent model for simulation of sylvian fissure dissection and cerebrovascular bypass under SAH conditions.METHODSA standardized microvascular anastomosis model comprising rat femoral arteries and veins was used for the experimental framework. In the experimental protocol, following exposure and skeletonization of the vessels, extensive, superficial (1- to 2-mm) soft-tissue debridement was conducted and followed by wound closure and delayed reexploration at intervals of 7, 14, and 28 days. Two residents dissected 1 rat each per time point (n = 6 rats), completing vessel skeletonization followed by end-to-end artery/vein anastomoses. Videos were reviewed postprocedure to assess scar score and relative difficulty of dissection by blinded raters using 4-point Likert scales.RESULTSAt all time points, vessels were markedly invested in friable scar, and exposure was subjectively assessed as a reasonable surrogate for sylvian fissure dissection under SAH conditions. Scar score and relative difficulty of dissection both indicated 14 days as the most challenging time point.CONCLUSIONSThe authors' experimental model of femoral vessel skeletonization, circumferential superficial soft-tissue injury, and delayed reexploration provides a novel approximation of sylvian fissure dissection and cerebrovascular bypass under SAH conditions. The optimal reexploration interval appears to be 7-14 days. To the authors' knowledge, this is the first model of SAH simulation for microsurgical training, particularly in a live animal system.

Incidence of and Risk Factors for Residual Anastomoses in Twin-Twin Transfusion Syndrome Treated with Laser Surgery: A 15-Year Single-Center Experience.

OBJECTIVES: To evaluate the incidence of residual anastomoses (RA) after laser therapy for twin-twin transfusion syndrome (TTS) and investigate risk factors for incomplete laser surgery. MATERIAL AND METHODS: All available TTS placentas treated with laser at our center between 2002 and 2016 were injected with color dye to assess the presence of RA. We evaluated the incidence of RA over the past 15 years by dividing the cohort into three time periods, and studied the association with risk factors and neonatal outcome. RESULTS: Overall, RA were detected in 21.0% (78/371) of placentas. The incidence of RA decreased from 38.8% (26/67) in the initial period to 11.7% (16/137) in the most recent period (p < 0.001). On multivariate analysis, several risk factors were independently associated with the risk of RA, including Solomon laser technique (odds ratio [OR] 0.17, 95% CI 0.09-0.33) and estimation of surgical success (OR 19.28, 95% CI 8.17-45.49). Premature delivery and neonatal morbidity occurred more often in TTS cases with RA. CONCLUSIONS: The incidence of RA after laser therapy for TTS decreased significantly in the past 15 years and is now below 15% due to the use of the Solomon technique.

The Concept of Door-to-Surgery Time in Distal Digital Replantation.

BACKGROUND: Digital replantation has become a well-established technique that has revolutionized hand surgery. One of the most important factors to a successful replantation is less than 12 hours of warm and 24 hours of cold ischemia time. The purpose of this article was to present a concept of door-to-surgery time and test the hypothesis that success in distal digital replantation is associated with this time. METHODS: Forty-five patients with 49 distal amputations were included in the study. Data regarding patient demographics, amputation characteristics, ischemia time, and surgical outcome were collected. Factors related to a successful replantation were analyzed. Fisher's exact test was used for statistical analysis. RESULTS: Type I, II, and III Yamano classification were noted in 11 (22.4%), 11 (22.4%), and 27 (55.1%) amputations. All the digits had arterial anastomoses while 19 (38.8%) digits were replanted without venous anastomosis. The mean door-to-surgery time was 229 minutes. The overall success rate was 77.6%. There were no differences in the survival rates between replantations with or without venous anastomosis. Patients with less than 180 minutes of door-to-surgery time had a significantly better survival rate compared to patients with greater time. CONCLUSION: The overall success rate was 77.6%. Patients with less than 180 minutes of door-to-surgery time had a significantly greater success rate (95.0%) compared to patients with longer door-to-surgery time (65.5%). Further effort must be made to achieve this goal in digital replantation.

The triune of intestinal microbiome, genetics and inflammatory status and its impact on the healing of lower gastrointestinal anastomoses.

Gastrointestinal resections are a common operation and most involve an anastomosis to rejoin the ends of the remaining bowel to restore gastrointestinal (GIT) continuity. While most joins heal uneventfully, in up to 26% of patients healing fails and an anastomotic leak (AL) develops. Despite advances in surgical technology and techniques, the rate of anastomotic leaks has not decreased over the last few decades raising the possibility that perhaps we do not yet fully understand the phenomenon of AL and are thus ill-equipped to prevent it. As in all complex conditions, it is necessary to isolate each different aspect of disease for interrogation of its specific role, but, as we hope to demonstrate in this article, it is a dangerous oversimplification to consider any single aspect as the full answer to the problem. Instead, consideration of important individual observations in parallel could illuminate the way forward towards a possibly simple solution amidst the complexity. This article details three aspects that we believe intertwine, and therefore should be considered together in wound healing within the GIT during postsurgical recovery: the microbiome, the host genetic make-up and their relationship to the perioperative inflammatory status. Each of these, alone or in combination, has been linked with various states of health and disease, and in combining these three aspects in the case of postoperative recovery from bowel resection, we may be nearer an answer to preventing anastomotic leaks than might have been thought just a few years ago.

A comparison of postoperative morphometric and hemodynamic changes between saphenous vein and left internal mammary artery grafts.

There is higher long-term failure of the saphenous vein graft (SVG) compared with the left internal mammary artery (LIMA) graft, which is affected by the hemodynamic environment. A comprehensive analysis of postoperative structure-function changes is important to study the atherogenesis in the SVG A comparison of morphometric and hemodynamic parameters was carried out between LIMA grafts and SVGs and between different time points postoperatively. Various parameters were obtained from the image reconstruction and flow simulation in patients, who underwent CT exams for ~1 year, 5 and 10 years after revascularization. Morphometric data showed a decrease in lumen size in the entire SVG and anastomosis of different patients in a sequence of ~1 year, 5 and 10 years postoperatively despite negligible changes of LIMA size. Computational results indicated the fourfold increased surface area ratio (SAR) of low time-averaged wall shear stress (TAWSS) in the SVG and anastomosis at postoperative 10 years than that at postoperative ~1 year. The SAR of high TAWSS gradient (TAWSSG) at the distal anastomosis between SVG and coronary arteries was significantly higher (14 ± 9% vs. 6 ± 8%) than that in the LIMA group at postoperative ~1 year. There were strong correlations between morphometric and hemodynamic parameters in the SVG and distal anastomosis at various time points postoperatively, which showed deterioration relevant to persistent diffuse diseases at postoperative ~10 years.

Substitution-rate based screening model to assess stenosis progression in experimental stenotic arteriovenous grafts.

An arteriovenous graft (AVG) has a higher patency rate in stenosis progression at the venous anastomosis site, which causes coexisting inflow and outflow stenoses. This leads to increases in blood pressure, flow velocity, and flow resistance, resulting in hemodialysis (HD) vascular access dysfunction from early clots and thrombosis to the progression of coexisting stenoses. To prevent vascular access complications such as inflow or outflow stenoses, this study proposes a novel examination method in an experimental AVG system using a substitution-rate based screening model. In our practical measurements, we found that inflow and outflow channeled through a narrowed access indicated both pressure and resistance differences as the degree of stenosis (DOS) gradually increased. A substitution-rate matrix was conducted to replace bilateral pressure variations, while a transition probability matrix was calculated. Differences in transition probabilities were then used to distinguish between normal conditions and flow instabilities using the distance estimation method. The joint probability decayed from < 0.81 to 0.00 could be specified to identify the progression in stenosis levels from a DOS% = 50.0-95.0%. Average joint probabilities were found to be inversely related with the DOS using a non-linear regression (R>2 0.90). Hence, the joint probability could be specified as a critical threshold, < 0.81, to identify the severity stenosis level, DOS% ⩾ 70%, in the assessment of coexisting inflow and outflow stenoses. Experimental results suggest that the proposed model is superior to hemodynamic analysis and traditional intelligent method, and can be used for dysfunction screening during HD treatment.

Alternativas quirúrgicas para el tratamiento de la trombosis venosa portal en el trasplante hepático / Surgical alternatives in the treatment of portal vein thrombosis in liver transplantation

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Evolution of Stage 1 Twin-to-Twin Transfusion Syndrome (TTTS): Systematic Review and Meta-Analysis.

OBJECTIVES: The natural history of stage 1 Twin-to-twin transfusion syndrome (TTTS) remains unclear and its optimal management is yet to be established. The main aims of this meta-analysis were to quantify the incidence of progression in stage 1 TTTS and to ascertain survival in these pregnancies. METHODS: MEDLINE, EMBASE, and The Cochrane Library were searched. Reference lists within each article were hand-searched for additional reports. The outcomes included incidence of progression and survival in stage 1 TTTS. Randomized controlled trials, cohort and case-control studies were included. Case reports, studies including three or fewer cases of stage 1 TTTS, and editorials were excluded. Proportion meta-analysis was used for analysis (Registration number: CRD42016036190). RESULTS: The search yielded 3,085 citations; 18 studies were included in the review (172 pregnancies to assess progression and 433 pregnancies to assess the survival). The pooled incidence of progression in stage 1 TTTS was 27% [95% CI 16-39%]. The pooled overall survival, double survival and at least one survival in the pregnancies managed expectantly were 79% [95% CI 62-92%], 70% [95% CI 54-84%] and 87% [95% CI 69-98%], respectively. In those undergoing amnioreduction, the corresponding figures were 77% [95% CI 68-85%], 67% [95% CI 57-76%] and 86% [95% CI 76-94%], respectively. The survival rates were 68% [95% CI 54-81%], 54% [95% CI 36-72%], and 81% [95% CI 69-90%], when laser surgery was performed. CONCLUSIONS: The optimal initial management of stage 1 TTTS remains in equipoise. The ongoing randomized trial comparing immediate laser surgery versus conservative management should provide a definitive answer.

The History of Treatment of Twin-to-Twin Transfusion Syndrome.

Historical suggestions of twin-to-twin transfusion syndrome (TTTS) date back to the early 17th century. Placental anastomoses were first reported in 1687; however, it was Schatz who first identified their importance in 1875. He recognized 'the area of transfusion' within the 'villous district' of the placenta, which he named the 'third circulation'. This article describes how the management of TTTS has evolved as we have gained a more sophisticated understanding and appreciation of the complex vascular anastomoses that exist in monochorionic twin placentae. Currently, fetosopic laser occlusion is the preferred treatment option for TTTS.

Laser Treatment of Twin-to-Twin Transfusion Syndrome.

OBJECTIVE: Laser ablation of all placental vascular anastomoses is the optimal treatment for twin-twin transfusion syndrome (TTTS). However, two important controversies are apparent in the literature: (a) a gap between concept and performance, and (b) controversy regarding whether all the anastomoses can be identified endoscopically and whether blind lasering of healthy placenta is justified. The purpose of this article is: (a) to address the potential source of the gap between concept and performance by analyzing the fundamental steps needed to successfully accomplish the surgery, and (b) to discuss the resulting competency benchmarks reported with the different surgical techniques. MATERIALS AND METHODS: Laser surgery for TTTS can be broken down into two fundamental steps: (1) endoscopic identification of the placental vascular anastomoses, (2) laser ablation of the anastomoses. The two steps are not synonymous: (a) regarding the endoscopic identification of the anastomoses, the non-selective technique is based upon lasering all vessels crossing the dividing membrane, whether anastomotic or not. The selective technique identifies and lasers only placental vascular anastomoses. The Solomon technique is based on the theory that not all anastomoses are endoscopically visible and thus involves lasering healthy areas of the placenta between lasered anastomoses, (b) regarding the actual laser ablation of the anastomoses, successful completion of the surgery (i.e., lasering all the anastomoses) can be measured by the rate of persistent or reverse TTTS (PRTTTS) and how often a selective technique can be achieved. Articles representing the different techniques are discussed. RESULTS: The non-selective technique is associated with the lowest double survival rate (35%), compared with 60-75% of the Solomon or the Quintero selective techniques. The Solomon technique is associated with a 20% rate of residual patent placental vascular anastomoses, compared to 3.5-5% for the selective technique (p < .05). Both the Solomon and the selective technique are associated with a 1% risk of PRTTTS. Adequate placental assessment is highest with the selective technique (99%) compared with the Solomon (80%) or the 'standard' (60%) techniques (p < .05). A surgical performance index is proposed. CONCLUSION: The Quintero selective technique was associated with the highest rate of successful ablation and lowest rate of PRTTTS. The Solomon technique represents a historical backward movement in the identification of placental vascular anastomoses and is associated with higher rate of residual patent vascular communications. The reported outcomes of the Quintero selective technique do not lend support to the existence of invisible anastomoses or justify lasering healthy placental tissue.

Internal carotid artery stenosis with persistent primitive hypoglossal artery treated with carotid artery stenting: A case report and literature review.

Persistent primitive hypoglossal artery (PPHA) is a persistent carotid-basilar anastomosis. It rarely remains at birth. It occasionally may be a risk for ischemia and embolic infarction to the posterior cerebral circulation, especially in patients with carotid stenosis proximal to the origin of persistent primitive arteries. We describe a case of a 60-year-old woman with asymptomatic internal carotid artery (ICA) stenosis and ipsilateral PPHA successfully treated by carotid artery stenting (CAS). A few cases of CAS for ICA stenosis with PPHA have been reported, but the strategy and methods in each case were different because of its unique anatomy and hemodynamics. It is essential to prevent distal embolisms and preserve blood flow at the territory of both the ICA and PPHA. The protection method should be selected carefully. We review the literature and discuss appropriate treatment strategies.

Structural cure for reflex syncope?

The ROX Coupler is a device that allows creation of a central arteriovenous anastomosis at the iliac level. The device has been shown to improve exercise capacity in patients with chronic obstructive pulmonary disease and is CE marked for the treatment of resistant and uncontrolled hypertension. Reflex syncope is a challenging clinical condition with limited proven therapeutic options. We describe the resolution of symptoms and tilt table response of a patient who underwent insertion of a ROX Coupler to treat hypertension, and also incidentally had pre-existing vasodepressor syncope.

Masa cervical derecha secundaria a pseudoaneurisma de carótida común derecha / Right cervical mass secondary to a right common carotid artery pseudoaneurysm

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