The mesenteric entry site as a potential weak point in gastrointestinal anastomoses - findings from an ex-vivo biomechanical analysis.

PURPOSE: Gastrointestinal disorders frequently necessitate surgery involving intestinal resection and anastomosis formation, potentially leading to severe complications like anastomotic leakage (AL) which is associated with increased morbidity, mortality, and adverse oncologic outcomes. While extensive research has explored the biology of anastomotic healing, there is limited understanding of the biomechanical properties of gastrointestinal anastomoses, which was aimed to be unraveled in this study. METHODS: An ex-vivo model was developed for the biomechanical analysis of 32 handsewn porcine end-to-end anastomoses, using interrupted and continuous suture techniques subjected to different flow models. While multiple cameras captured different angles of the anastomosis, comprehensive data recording of pressure, time, and temperature was performed simultaneously. Special focus was laid on monitoring time, location and pressure of anastomotic leakage (LP) and bursting pressures (BP) depending on suture techniques and flow models. RESULTS: Significant differences in LP, BP, and time intervals were observed based on the flow model but not on the suture techniques applied. Interestingly, anastomoses at the insertion site of the mesentery exhibited significantly higher rates of leakage and bursting compared to other sections of the anastomosis. CONCLUSION: The developed ex-vivo model facilitated comparable, reproducible, and user-independent biomechanical analyses. Assessing biomechanical properties of anastomoses offers an advantage in identifying technical weak points to refine surgical techniques, potentially reducing complications like AL. The results indicate that mesenteric insertion serves as a potential weak spot for AL, warranting further investigations and refinements in surgical techniques to optimize outcomes in this critical area of anastomotic procedures.

A Novel Machine Learning-Based Point-Score Model as a Non-Invasive Decision-Making Tool for Identifying Infected Ascites in Patients with Hydropic Decompensated Liver Cirrhosis: A Retrospective Multicentre Study.

This study is aimed at assessing the distinctive features of patients with infected ascites and liver cirrhosis and developing a scoring system to allow for the accurate identification of patients not requiring abdominocentesis to rule out infected ascites. A total of 700 episodes of patients with decompensated liver cirrhosis undergoing abdominocentesis between 2006 and 2020 were included. Overall, 34 clinical, drug, and laboratory features were evaluated using machine learning to identify key differentiation criteria and integrate them into a point-score model. In total, 11 discriminatory features were selected using a Lasso regression model to establish a point-score model. Considering pre-test probabilities for infected ascites of 10%, 15%, and 25%, the negative and positive predictive values of the point-score model for infected ascites were 98.1%, 97.0%, 94.6% and 14.9%, 21.8%, and 34.5%, respectively. Besides the main model, a simplified model was generated, containing only features that are fast to collect, which revealed similar predictive values. Our point-score model appears to be a promising non-invasive approach to rule out infected ascites in clinical routine with high negative predictive values in patients with hydropic decompensated liver cirrhosis, but further external validation in a prospective study is needed.

Smart antimicrobial efficacy employing pH-sensitive ZnO-doped diamond-like carbon coatings.

One of the main challenges in endoprosthesis surgeries are implant-associated infections and aseptic-loosenings, caused by wear debris. To combat these problems, the requirements to surfaces of endoprostheses are wear-resistance, low cytotoxicity and antimicrobial efficacy. We here present antimicrobial coatings with a smart, adaptive release of metal ions in case of infection, based on ZnO-nanoparticles embedded in diamond-like carbon (DLC). The Zn2+ ion release of these coatings in aqueous environments reacts and adapts smartly on inflammations accompanied by acidosis. Moreover, we show that this increased ion release comes along with an increased toxicity to fibroblastic cells (L929) and bacteria (Staphylococcus aureus subsp. aureus, resistant to methicillin and oxacillin. (ATCC 43300, MRSA) and Staphylococcus epidermidis (ATCC 35984, S. epidermidis). Interestingly, the antimicrobial effect and the cytotoxicity of the coatings increase with a reduction of the pH value from 7.4 to 6.4, but not further to pH 5.4.

[42-year-old patient with portal hypertension - case 6/2012]. / 42-jährige Patientin mit portaler Hypertension - Fall 6/2012.

HISTORY AND ADMISSION FINDINGS: A 42-year-old woman was referred with a bleeding in the upper gastrointestinal tract, varices in the fundus of the stomach and portal hypertension of unknown primary. INVESTIGATIONS: Ultrasound examinations showed splenomegaly as well as portal hypertension. Blood examinations revealed low levels of haemoglobin. CT imaging showed multiple arteriovenous malformations with arterioportal shunts within the liver which led to a volume-induced portal hypertension. The genetic analysis revealed no mutations in the activin receptor-like kinase (ALK) 1 or endoglin genes. DIAGNOSIS, TREATMENT AND COURSE: The patient was clinically diagnosed with hereditary hemorrhagic teleangiectasia, also known as Osler-Weber-Rendu disease. Because of the multiple arterioportal shunts within the liver and the resulting portal hypertension with live-threatening gastrointestinal bleeding, the only therapeutic option for the patient is liver transplantation. Therefore, an application for a standard exception was made at Eurotransplant and the patient is going to be liver transplantated within the next months. CONCLUSIONS: Osler-Weber-Rendu disease is an autosomal dominant hereditary disease which leads to arteriovenous malformations and which can affect different organ systems. The course of the disease can be rather benign, but it can also lead to live-threatening complications requiring fast interventions.

Endovascular repair of acute symptomatic pararenal aortic aneurysm with three chimney and one periscope graft for complete visceral artery revascularization.

PURPOSE: To describe a modified endovascular technique for complete revascularization of visceral and renal arteries in symptomatic pararenal aortic aneurysm (PRAA). TECHNIQUE: Arterial access was surgically established in both common femoral arteries (CFAs) and the left subclavian artery (LSA). Revascularization of the left renal artery, the celiac trunk, and the superior mesenteric artery was performed through one single sheath via the LSA. Suitable covered stents were put in the aortic branches but not deployed. The right renal artery was accessed over the left CFA. Due to the longitudinal extension of the presented aneurysm two stent-grafts were introduced via the right CFA. After deploying the aortic stent-grafts, all covered stents in the side branches were deployed consecutively with a minimum overlap of 5 mm over the cranial and caudal stent-graft edges. Simultaneous ballooning was performed to fully expand all stent-grafts and warranty patency. CONCLUSION: This is the first report in the literature of chimney grafting in PRAA for complete revascularization of visceral and renal branches by using more than two covered stents introduced from one side through one single sheath. However this technique is modified, it should be used only in bailout situations when branched stent-grafts are not available and/or surgery is not suitable.

Epithelioid angiosarcoma with metastatic disease after endovascular therapy of abdominal aortic aneurysm.

Malignancies of the aortic wall represent a rare condition, and only a few reports have covered cases of sarcomas arising at the site of a prosthesis made of Dacron. A coincidence with endovascular repair has only been reported in one case to date. We report a patient with epithelioid angiosarcoma and metastatic disease, which was found in an aneurysmal sac after endovascular aortic repair for abdominal aortic aneurysm.

Stent-assisted embolization as "bailout" option in aortic aneurysm.

The authors report two cases of stent-assisted embolization (SAE) in the aorta. In one case, SAE was performed for treatment of a pseudoaneurysm; the procedure consisted of stent placement and embolization with an AMPLATZER Vascular Plug and detachable coils through the stent struts. In the second case, SAE was performed to stop acute bleeding from an aortoureteral fistula. Before SAE in this case, the aortic bifurcation was reconstructed with self-expandable and balloon-expandable stents. SAE was technically successful in both cases. SAE for aortic pathologic processes may be useful in selected cases as an alternative to surgery or endovascular stent-graft therapy.

Endovascular treatment of venous graft stenosis in the inferior vena cava and the left hepatic vein after complex liver tumor resection.

Endovascular treatment has been reported for a variety of conditions that result in venous obstruction in the iliocaval territory. The present report describes a patient who underwent a complex resection of a tumor that infiltrated the retrohepatic segment of the inferior vena cava (IVC), necessitating replacement of the IVC with a polytetrafluoroethylene (PTFE) graft. Postoperatively, symptomatic venous obstruction occurred in the graft and the left hepatic vein. Treatment required stent placement bridging native veins and the graft. The patient underwent placement of a self-expanding stent within the IVC and the PTFE graft with treatment of the hepatic vein stenosis via jugular vein access.

Local delivery of paclitaxel to inhibit restenosis during angioplasty of the leg.

BACKGROUND: Drug-eluting stents reduce restenosis in coronary arteries, but clinical trials have failed to prove their efficacy in peripheral arteries. We investigated the use of paclitaxel-coated angioplasty balloons and paclitaxel dissolved in the angiographic contrast medium during angioplasty of the leg. METHODS: In a small, multicenter trial, we randomly assigned 154 patients with stenosis or occlusion of a femoropopliteal artery to treatment with standard balloon catheters coated with paclitaxel, uncoated balloons with paclitaxel dissolved in the contrast medium, or uncoated balloons without paclitaxel (control). The primary end point was late lumen loss at 6 months. RESULTS: The mean (+/-SD) age of the patients was 68+/-8 years, 24% were smokers, and 49% had diabetes. Twenty-seven percent of the lesions were total occlusions, and 36% were restenotic lesions. The mean lesion length was 7.4+/-6.5 cm. There were no significant differences in baseline characteristics between the groups. There were no adverse events attributable to the paclitaxel-coated balloons. At 6 months, the mean late lumen loss was 1.7+/-1.8 mm in the control group, as compared with 0.4+/-1.2 mm (P<0.001) in the group treated with paclitaxel-coated balloons and 2.2+/-1.6 mm (P=0.11) in the group treated with paclitaxel in the contrast medium. The rate of revascularization of target lesions at 6 months was 20 of 54 (37%) in the control group, 2 of 48 (4%) in the group treated with paclitaxel-coated balloons (P<0.001 vs. control), and 15 of 52 (29%) in the group treated with paclitaxel in the contrast medium (P=0.41 vs. control); at 24 months, the rates increased to 28 of 54 (52%), 7 of 48 (15%), and 21 of 52 (40%), respectively. CONCLUSIONS: Use of paclitaxel-coated angioplasty balloons during percutaneous treatment of femoropopliteal disease is associated with significant reductions in late lumen loss and target-lesion revascularization. No significant benefit is seen with the use of a paclitaxel-containing contrast medium. (ClinicalTrials.gov number, NCT00156624 [ClinicalTrials.gov].).

Self-expanding nitinol stents for treatment of infragenicular arteries following unsuccessful balloon angioplasty.

The feasibility of self-expanding nitinol stents for treatment of infragenicular arteries following unsuccessful balloon angioplasty was assessed. Options for lower limb percutaneous revascularization are limited, especially for complex vessel obstruction. Depending on the lesion and the experience of the interventionalist, the failure rate of balloon angioplasty (PTA) ranges between 10 and 40%. Until recently, no self-expanding stent for the use in the infragenicular arteries was available. This is the first report of the results for 18 consecutive patients who received 4F sheath compatible self-expanding nitinol stents following unsuccessful PTA or early restenosis. Twenty-four stents were implanted in 21 lesions for various indications residual stenosis >50% due to heavy calcification, flow-limiting dissection, occluding thrombus resistant to thrombolyis, thrombaspiration, and PTA, and early restenosis after previous PTA. Stent implantation was feasible in all cases. No complications occurred. After the stent implantation, all primarily unsuccessful interventions could be transformed into successful procedures with no residual stenosis >30% in any case. After 6 +/- 2 months, two of the 18 patients died, and 14 of the 16 remaining patients improved clinically. At follow-up, the patency could be assessed in 14 stented arteries. Three stents were occluded, one stent showed some neointimal hyperplasia (50-70% restenosis), the remaining ten stents showed no restenosis (0-30%). The use of self-expanding nitinol stents in tibioperoneal and popliteal arteries is a safe and feasible option for the treatment of unsuccessful PTA. The 6-months patency is high.

Peripheral arteries: treatment with antibodies of platelet receptors and reteplase for thrombolysis--APART trial.

PURPOSE: To prospectively compare the safety and efficacy of combination therapy with the glycoprotein IIb/IIIa antagonist abciximab plus the third-generation thrombolytic agent reteplase versus those of therapy with the standard thrombolytic agent urokinase plus abciximab. MATERIALS AND METHODS: The study was approved by the local ethics committee, and patient informed consent was obtained. Patients with peripheral arterial occlusions less than 60 days old (n=120) were enrolled in the study: 50 patients (32 men, 18 women; mean age, 67 years; range, 23-88 years) received reteplase plus abciximab and 70 patients (36 men, 34 women; mean age, 68 years; range, 28-88 years) received urokinase plus abciximab. Study end points were the rate of major complications at 30 days, therapeutic success, and survival without open surgery or major amputation at follow-up. Fisher exact test was used to compare treatment groups with respect to dichotomous variables, and the event-free-survival probabilities were calculated with the Kaplan-Meier method. For the comparison of the lengths of occlusions among the groups, a two-sample t test was used. RESULTS: Therapeutic success (P=.7) did not differ between the groups, whereas the time required for thrombolysis was lower in the urokinase-plus-abciximab group (P=.001). Patients who received reteplase plus abciximab tended to develop more minor complications (mainly bleeding events) (P<.001). During long-term follow-up (2-4 years), no group differences were observed. The reocclusion rate was 48% (22 of 46) in the reteplase-plus-abciximab group and 45% (29 of 64) in the urokinase-plus-abciximab group. Only two of 120 major amputations were counted in the follow-up period. CONCLUSION: The proposed regimen resulted in only a limited number of major complications, and the low amputation rate in both groups may be attributed to abciximab.

Superficial femoral artery: current treatment options.

Treatment of the superficial femoral artery (SFA) has been among the least effective of all endovascular procedures in terms of long-term patency. The relatively small vessel lumen, in conjunction with a high plaque burden, slow flow, and a high frequency of primary occlusions, contributes to a considerable rate of acute technical failures. Because of these technical limitations a much effort has been made during the past years. This manuscript should summarize the hopes and limitations of different approaches such as brachytherapy, cutting balloons, stents and stent grafts, drug-eluting stents, and drug-coated balloons.

Reduced thrombogenicity of nitinol stents--in vitro evaluation of different surface modifications and coatings.

The material and the surface patterns of intravascular stents play a pivotal role in activating platelets and triggering adherence of inflammatory cells that consecutively leads to renarrowing caused by neointimal hyperplasia. To improve these features, besides mechanical and chemical modifications, ways of masking the stent by covering have been developed. In addition, polymer-coated stents are used as vehicle for local drug delivery. But as substances used for this application are described to possess an inflammatory potential, this aspect has to be evaluated. In the present study we compared different approaches to surface alterations applied to a nitinol stent design. Besides commonly used techniques like passivation and electropolishing, we evaluated coatings with heparin, aluminium and a polyurethane polymer regarding their thrombogenic and inflammatory characteristics. By weaving thin elastomer fibres a graft was generated. The previously described Chandler loop was used to simulate arterial flow conditions ex vivo using rotating PVC tubings filled with human blood. All stents received 120 min of blood contact. To determine thrombocyte activation and inflammatory reaction, the platelet count and levels of beta-TG, TAT and PMN-elastase were assessed. Scanning electron microscopy was used to visualize the reactions. Mechanical polishing and passivation did not improve the stent surface characteristics while sandblasting, electropolishing and aluminium covering decreased activation of the coagulation cascade. In terms of thrombogenicity, the heparin coating had no beneficial effect. The lowest thrombogenic potential was found in the Polyurethane-coated stent group. All stents showed similar levels of polymorph nuclear granulocyte elastase except for the membrane design. While mechanical and chemical modifications are able to reduce thrombogenicity, coating with this particular polyurethane polymer seems to be superior to these approaches regarding the parameters assessed in this experimental setting. The Chandler loop is a valuable tool to test polymeric coatings ex vivo since these modifications may reduce drug performance by inducing inflammatory reaction themselves.