Vascular Prostheses Research Articles

Polycatecholamine and gentamicin as modifiers for antibacterial and blood-biocompatible polyester vascular prostheses

Polyester (PET) prostheses are commonly used in reconstructive vascular surgery. The most serious complication after implantation is early or late infection of the graft. Therefore, there is high demand to protect prosthesis against bacterial adhesion and biofilm development. For this reason, in this work PET prostheses were first coated by highly adhesive polycatecholamine layer. The grafts were then coupled with gentamicin and studied in relation to morphological and structural properties, biological safety (contact with blood, reaction of vascular endothelial cells (HUVEC), Danio rerio fish), drug release and antibacterial activity. Among two tested catecholamine monomers, L-DOPA was found to be more effective precursor in this process than dopamine. For L-DOPA, assistance of Cu2+, Mg2+ and Na+ ions seems to increase the amount of further immobilized drug. Coated prostheses exhibited greater human endothelial cell proliferation increase and lower cytotoxic effect than uncoated. The modification reduced the hemolysis observed for pristine commercial graft and limited the rate of abnormalities in D. rerio larvae, confirming the safety of the proposed modification. The coating allowed to double the amount of immobilized antibiotic in comparison with uncoated graft which resulted in increased antibacterial activity and reduced bacterial adhesion against 4 bacterial strains prevalent in biomaterials infections. Overall, poly(L-DOPA)-coatings deposited on PET vascular grafts can effectively functionalize these prostheses for higher safety in biomedical applications.

Fabrication of heparinized small diameter TPU/PCL bi-layered artificial blood vessels and in vivo assessment in a rabbit carotid artery replacement model

Increasingly growing problems in vascular access for long-term hemodialysis lead to a considerable demand for synthetic small diameter vascular prostheses, which usually suffer from some drawbacks and are associated to high failure rates. Incorporating the concept of in situ tissue engineering (TE) into synthetic small diameter blood vessels, for example, thermoplastic poly(ether urethane) (TPU) ones, could provide an alternative approach for vascular access that profits from the advantages of excellent mechanical properties of synthetic polymer materials (early cannulation) and unique biointegration regeneration of autologous neovascular tissues (long-term fistulae). In this study, a kind of heparinized small diameter (d = 2.5 mm) TPU/poly(ε-caprolactone) (TPU/PCL-Hep) bi-layered blood vessels was electrospun with an inner layer of PCL and an outer layer of TPU. Afterward, the inner surface heparinization was conducted by coupling H2N-PEG-NH2 to the corroded PCL layer and then heparin to the attached H2N-PEG-NH2 via the EDCI/NHS chemistry. Herein a heparinized PCL inner layer could not only inhibit thrombosis, but also provide sufficient space for the neotissue regeneration via biodegradation with time. Meanwhile, a TPU outer layer could confer the vascular access the good mechanical properties, such as flexibility, viability and fitness of elasticity between the grafts and host blood vessels as evidenced by the adequate mechanical properties, such as compliance (4.43 ± 0.07%/ 100 mmHg), burst pressure (1447 ± 127 mmHg) and suture retention strength (1.26 ± 0.07 N) without blood seepage after implantation. Furthermore, a rabbit carotid aortic replacement model for 5 months was demonstrated 100% animal survival and 86% graft patency. Puncture assay also revealed the puncture resistance and self-sealing (hemostatic time < 2 min). Histological analysis highlighted neotissue regeneration, host cell infiltration and graft remodeling in terms of extracellular matrix turnover. Altogether, these results showed promising aspects of small diameter TPU/PCL-Hep bi-layered grafts for hemodialytic vascular access applications.

Facilitation of adhesion and spreading of endothelial cells on silicone oxide-coated dacron material by microwave-excited low-pressure plasma.

ObjectivesAutologous transplants are still the means of choice for bypass surgery. In addition to good tolerability, there is a reduced thrombogenicity and fewer neointima hyperplasia compared to artificial materials. However, since viable transplants are limited, attempts are being made to improve existing artificial vascular prosthesis material. Next to the reduction of thrombogenicity, a rapid endothelialization of the vascular graft should reduce intimal hyperplasia and thus prevent stenoses. The effect of newly developed silicon oxide coatings on the growth of endothelial cells was therefore the goal of this work in a cell culture study.MethodsA woven, uncoated polyethylene terephthalate (PET) vessel prosthesis was used. The coating process was carried out in a low-pressure plasma reactor in a multi-step process. After preparation of the vacuum chamber hexamethyldisiloxane (HDMSO) with oxygen was evaporated using argon plasma. By this an approx. 1 nm thin adhesion promoter layer was separated from plasma and HMDSO. The silicone oxide barrier layer was applied to the PET vessel samples. The carbon content of the layer could be selectively altered by changing the HMDSO oxygen flow ratio, resulting in coatings of 100 nm, 500 nm, and 1,000 nm. In addition, two different oxygen-to-HMDSO ratios were used. To achieve a carbon coating as low as possible, the ratio was set to 200:1. A carbon-rich layer was obtained with the 1:1 setting. The various coatings were then examined for their surface texture by scanning electron microscopy (SEM) as well as by cell culture experiments for cell viability and growth using EA.hy 926 cells.ResultsSEM showed no changes in the surface morphology; however a layer thickness of 1,000 nm showed peeled off coating areas. Alamar blue assays showed a significantly higher metabolic activity (p=0.026) for the coating 500 nm, ratio 200:1 compared to untreated control samples and a significantly lower metabolic activity (p=0.037) of the coating 500 nm, ratio 1:1 compared to the coating 500 nm, ratio 200:1. This underlines the apparent tendency of the 1:1 coating to inhibit the metabolic activity of the cells, while the 200:1 coating increases the activity. Fluorescence microscopy after calcein acetoxymethyl ester (AM) staining showed no significant difference between the different coatings and the uncoated PET material. However, a tendency of the increased surface growth on the coating 500 nm, ratio 200:1, is shown. The coatings with the ratio 1:1 tend to be less densely covered.ConclusionsThe results of this work indicate a great potential in the silicon coating of vascular prosthesis material. The plasma coating can be carried out easy and gently. Cell culture experiments demonstrated a tendency towards better growth of the cells on the 200:1 ratio coating and a poorer growth on the carbon-rich coating 1:1 compared to the uncoated material. The coating with silicon oxide with a thickness of 500 nm and an oxygen-HMDSO ratio of 200:1, a particularly low-carbon layer, appears to be a coating, which should therefore be further investigated for its effects on thrombogenicity and intimal hyperplasia.

Vascular implants - new aspects for in situ tissue engineering.

Conventional synthetic vascular grafts require ongoing anticoagulation, and autologous venous grafts are often not available in elderly patients. This review highlights the development of bioartificial vessels replacing brain‐dead donor‐ or animal‐deriving vessels with ongoing immune reactivity. The vision for such bio‐hybrids exists in a combination of biodegradable scaffolds and seeding with immune‐neutral cells, and here different cells sources such as autologous progenitor cells or stem cells are relevant. This kind of in situ tissue engineering depends on a suitable bioreactor system with elaborate monitoring systems, three‐dimensional (3D) visualization and a potential of cell conditioning into the direction of the targeted vascular cell phenotype. Necessary bioreactor tools for dynamic and pulsatile cultivation are described. In addition, a concept for design of vasa vasorum is outlined, that is needed for sustainable nutrition of the wall structure in large caliber vessels. For scaffold design and cell adhesion additives, different materials and technologies are discussed. 3D printing is introduced as a relatively new field with promising prospects, for example, to create complex geometries or micro‐structured surfaces for optimal cell adhesion and ingrowth in a standardized and custom designed procedure. Summarizing, a bio‐hybrid vascular prosthesis from a controlled biotechnological process is thus coming more and more into view. It has the potential to withstand strict approval requirements applied for advanced therapy medicinal products.

Intrahepatic Vein Resection and Reconstruction with a Prosthethic Graft

In the last decades the concept of liver surgery for the treatment of colorectal liver metastases (CLM) turned from “How much CLM can I resect?” to “How much liver parenchyma can I spare?”. In addition, the out-flow vascular preservation of the future liver remnant is crucial. Even if there are situations in which we can sacrifice 1, 2 or even 3 hepatic veins, there are others in which we cannot, or are not sure whether to do so. Hepatic vein resection and reconstruction with or without a vascular graft has already been reported. However, these procedures are usually performed near hepatocaval confluence. Here we present a technique to perform an intrahepatic deep segmental vein resection due to tumor infiltration, with a subsequent reconstruction with a vascular prosthesis. Regarding the technique itself, once vessel tumor infiltration has been established with IOUS, we then transect the liver parenchyma in depth with a 2 cm margin from tumor edge. After reaching the hepatic vein, we must encircle it proximally and distally respect of tumor infiltration site. Next, we perform a selected venous vascular exclusion using bulldog clamps. Once the in-block-tumor/vein has been resected, we suture a 6 mm PTFE vascular prosthesis to replace the vein. Continuous running suture is performed with 6.0 prolene. At the end of the procedure, “growth factor” maneuver is carried out to avoid vascular stenosis. Intraoperative antiaggregation with 100 mg aspirin is started through a nasogastric tube.

Tratamento híbrido para revascularização de membro inferior em paciente com infecção de prótese vascular: relato de caso

Patients with severe arterial obstructive disease and critical limb ischemia associated with vascular graft infection have elevated morbidity and mortality rates and are at high risk of limb loss. We present the case of a 76-year-old male patient with left lower limb critical ischemia and a femoropopliteal vascular graft infection. We used a hybrid treatment approach with an open surgical approach to the inguinal and popliteal regions and used the vascular prosthesis as endovascular access for direct recanalization of the superficial femoral artery, because the long occlusion and extensive calcification had frustrated initial attempts at endovascular treatment. After endovascular recanalization, the infected graft was removed. Used in conjunction with open surgery, advances in endovascular techniques and materials offer new solutions for patients when usual procedures fail.

A novel technique with Dacron vascular graft augmentation for knee extensor mechanism repairs: Technical note

Ruptures of the extensor apparatus can have different etiologies and be complicated by underlying situations. Direct repair is not always possible, and reconstruction procedures can be insufficient, which leads to the appearance of multiple augmentation techniques to improve the strength of these constructs. Despite the proven results of these techniques, numerous procedures are described without any gold standard. We present our augmentation method for repairing the knee extensor apparatus with a vascular prosthesis that facilitates healing, does not interfere with the primary procedure, has no donor morbidity or rejection risk, and allows earlier mobilization and rehabilitation. The technique was used in different cases with multiple etiologies that needed reinforcement, with promising results.

Ultrastructure of neointima of native and artificial elements of the blood circulatory system

To compare the neointima structure in conduits for coronary bypass grafting, bioprosthetic heart valves, tissue-engineered vascular grafts, and metal stents. The objects of the study were the fragments of the human internal thoracic artery, experimental biodegradable vascular prostheses, leaflets of xenopericardial bioprostheses of heart valves, and fragments of stented vessels. Tissue samples were fixed in formalin and post-fixed in osmium tetroxide. After dehydration and epoxy resin embedding, the samples were ground and polished. Samples were counterstained with uranyl acetate and lead citrate and visualized by means of backscattered scanning electron microscopy. Neointimal pattern in all samples was similar. Neointima was comprised of endothelial cells, smooth muscle cells, fibroblasts, and the extracellular matrix. Endothelial cells showed significant diversity both between different elements of the circulatory system and within the same tissue, having either elongated or polygonal shape. Adhesion of leukocytes testified to the endothelial cell activation. In the absence of inflammation in the superficial layer of the neointima, the arrangement of smooth muscle cells and extracellular matrix fibers was parallel to the endothelium. Clusters of foam cells were frequently detected around the neointimal layers with solid inclusions (metal stents or calcium deposits). Thickening of the neointima was accompanied by the presence of capillaries and capillary-like structures. Neointima formation is a typical response to the damage inflicted to the elements of the circulatory system. Neointima underwent a constant remodeling characterized by an altered cellular composition, macrophage invasion, neovascularization, and calcification.

Remodeling of structurally reinforced (TPU+PCL/PCL)-Hep electrospun small-diameter bilayer vascular grafts interposed in rat abdominal aortas.

As thermoplastic polyurethane (TPU) elastomers possess good biocompatibility and mechanical properties similar to those of native vascular tissues, they were intended to be co-electrospun with poly(ε-caprolactone) (PCL) onto the outer surface of PCL electrospun small-diameter single-layer vascular grafts (SLVGs) in this study, combining with surface heparinization. In this work, a kind of structurally reinforced TPU+PCL/PCL small-diameter bilayer vascular graft (BLVG) was fabricated via layer-by-layer electrospinning followed by the heparinization of PCL via EDC/NHS chemistry. The resulting (TPU+PCL/PCL)-Hep BLVGs presented excellent mechanical strength and higher compliance, and sustainably released heparin exhibited enhanced anti-coagulation activity. During 6-month implantation in 18 rat abdominal aortas, these vascular prostheses induced the remodeling and regeneration of neovascular tissues, and promoted ECM deposition. Compared to heparinized PCL (PCL-Hep) SLVGs, the formation of aneurysm was completely inhibited and the onset of calcification was significantly delayed in (TPU+PCL/PCL)-Hep BLVGs. Not only vascular cell makers co-expressed by CD206+ cells were identified, but also a high content of elastin was evidenced due to the improvement of mechanical strength and compliance. These results indicated the feasibility and efficacy of inhibiting the aneurysm formation and boosting the vascular remodeling by incorporating TPU into PCL-Hep small-diameter artificial vascular grafts.

Артеріотрахеальна нориця як ускладнення пролонгованої трахеостомії

У статті наведений клінічний випадок рідкісного та тяжкого ускладнення пролонгованої трахеостомії у вигляді формування нориці між просвітом трахеї та брахіоцефальною артерією та розвитку масивної кровотечі з неї. Лікування пацієнта було ургентним й успішним. Пацієнту проведене оперативне втручання з наступним алопротезуванням плечоголовного стовбура (використаний судинний протез Vascutec 8 мм) та формуванням анастомозу методикою безперервного шва. На 17-ту післяопераційну добу пацієнта виписали додому в задовільному стані.

ВОЗМОЖНОСТИ ТРАНСПЛАНТАЦИИ СОСУДОВ В УРГЕНТНОЙ ХИРУРГИИ МАГИСТРАЛЬНЫХ АРТЕРИЙ

The article presents the experience of using allografts from a postmortem donor in emergency surgery of the main arteries of the lower extremities. Possible tactical methods of combined use of alloartery and allovein from various donors in urgent surgery have been demonstrated. High risks of interventions aimed at relieving early and late complications of vascular reconstructions remain an actual problem in angiosurgery. Very often, operations are performed in the presence of extensive necrosis and trophic ulcers (stage IV according to the Fontaine-Pokrovsky classification). Autovenous conduit from the great saphenous vein (type of arterial bed lesions C, D according to TASS II) was and remains the gold standard for choosing a shunt for reconstructive operations on infrainguinal arteries. In case of repeated reconstructions in the absence of a suitable autovein, in the presence of trophic ulcers and necrosis, an infectious process in the area of the vascular prosthesis, it is not always possible to use a synthetic prosthesis as a reliable alternative. Unsatisfactory results of using such materials dictate the need to choose a suitable graft. The problem of using allografts requires further advanced study. In this regard, the experience of using allografts in two non-standard urgent clinical situations is presented. The conclusion is made about the possibility of effective use of allografts from a postmortem donor in patients with bleeding after endovascular treatment of critical limb ischemia with trophic changes in the staged surgical treatment, as well as in patients with thrombosed anastomotic false aneurysms after previously performed surgical interventions.

Tobramycin Supplemented Small-Diameter Vascular Grafts for Local Antibiotic Delivery: A Preliminary Formulation Study.

Peripheral artery occlusive disease is an emerging cardiovascular disease characterized by the blockage of blood vessels in the limbs and is associated with dysfunction, gangrene, amputation, and a high mortality risk. Possible treatments involve by-pass surgery using autologous vessel grafts, because of the lack of suitable synthetic small-diameter vascular prosthesis. One to five percent of patients experience vascular graft infection, with a high risk of haemorrhage, spreading of the infection, amputation and even death. In this work, an infection-proof vascular graft prototype was designed and manufactured by electrospinning 12.5% w/v poly-L-lactic-co-glycolic acid solution in 75% v/v dichloromethane, 23.8% v/v dimethylformamide and 1.2% v/v water, loaded with 0.2% w/wPLGA. Polymer and tobramycin concentrations were selected after viscosity and surface tension and after HPLC-UV encapsulation efficiency (EE%) evaluation, respectively. The final drug-loaded prototype had an EE% of 95.58% ± 3.14%, with smooth fibres in the nanometer range and good porosity; graft wall thickness was 291 ± 20.82 μm and its internal diameter was 2.61 ± 0.05 mm. The graft’s antimicrobic activity evaluation through time-kill assays demonstrated a significant and strong antibacterial activity over 5 days against Staphylococcus aureus and Escherichia coli. An indirect cell viability assay on Normal Human Dermal Fibroblasts (NHDF) confirmed the cytocompatibility of the grafts.

Reductive annuloplasty with autopericardium in surgical treatment of mitral insufficiency

BACKGROUND: Despite the widespread usage of all-type rings in the surgical treatment of patients with mitral valve insufficiency (MV) and dilatation of its fibrous annulus, the researches on this topic are in progress.&#x0D; AIM: To study the short- and long-term results of narrowing annuloplasty of the MV utilizing an autopericardium strip of calculated length.&#x0D; MATERIALS AND METHODS: The study group consisted of 21 patients (average age 60.9 4.3 years, women 23.8 %) with MV insufficiency of non-rheumatic ethiology. The narrowing of the fibrous annulus during valve reconstruction has been performed along with the posterior 2/3 of their circle using interrupted horizontal sutures. With those sutures, an autopericardial strip of the calculated length has been secured to the annulus. The length of the strip has been calculated according to the original method, according to the data obtained during preoperative transesophageal echocardiography. The length of the strip was 2/3 ∙ D (mm), where D the existing length of the anterior leaflet of the MV in the middle portion from the fibrous annulus to the free edge in the zone of the A2 segment. The control group consisted of 38 patients with non-rheumatic MV insufficiency (average age 59.1 3.5 years, women 23.7 %); the strengthening and narrowing of the fibrous annulus have been performed using a strip made from a wicker vascular prosthesis. The length was 55 mm, equal for all the patients. In both groups, in addition to the narrowing of the fibrous annulus, other types of mitral valve-sparing surgery (partial resection of MV leaflets, suture leaflets techniques, their combination) and combined procedures (coronary bypass surgery, left ventricle reconstructions for postinfarction aneurysms) have been also performed.&#x0D; RESULTS: In the studied groups, the safety and reliability of the performed restrictive MV annuloplasty procedures have been demonstrated. During the follow-up period up to 8 years (average 3.5 0.7 years), there was no recurrence of significant mitral regurgitation, which would require repeated surgery in both groups. Narrowing annuloplasty of the fibrous annulus of MV with a strip from the autopericardium of an individual calculated length allows to perform a more accurate anatomical correction of the valve compared with the control group. The existing methods of mitral annuloplasty, their advantages and disadvantages are discussed.&#x0D; CONCLUSIONS: The proposed method of restrictive annuloplasty of the MV with an autopericardial strip of the calculated length allows to perform a reliable and safe correction of the dilated fibrous annulus in patients with mitral insufficiency during valve-preserving operations.

First Clinical Experience of Venous Reconstruction With Autologous Vascular Prosthesis From the Sickle Ligament of the Liver With Partial Portosystemic Bypass Surgery

Aim of study. Presentation of our own first clinical experience of venous reconstruction in portosystemic bypass surgery with the use of autologous vascular prostheses of the falciform ligament of the liver in the splenorenal position in a patient with portal hypertension syndrome in the outcome of liver cirrhosis of viral etiology.Material and methods. Clinical observation of a patient born in 1978 with a diagnosis of cirrhosis of the liver of viral etiology (HCV) Child-Pugh A (6). MELD 10 points. Inactive phase. Intrahepatic portal hypertension syndrome. Esophageal varices grade III according to A. G. Scherzinger, gastric varices type I (GOV1) according to Sarin. Condition after repeated recurrent esophageal-gastric bleeding. Due to the high risk of another bleeding, as a secondary prevention of esophageal-gastric bleeding, partial splenorenal anastomosis of “H” - type was performed with the use of an autologous vascular prosthesis of the falciform ligament of the liver in the splenorenal position.Results. A flap measuring 60.0x20.0 mm was cut from the falciform ligament of the patient’s liver. From the latter, after adjusting the size of the graft to the individual needs of the patient, an autologous conduit was formed. It was used as an insert in the formation of an “H” - type splenorenal anastomosis with the imposition of two end-to-side anastomoses between the splenic vein and one end of the conduit and between the left renal vein and the other end of the conduit. The patency of the anastomosis was checked using intraoperative sonography. In a satisfactory condition, the patient was discharged for outpatient follow-up treatment at the place of residence. At the moment of writing the article, the follow-up period was 8 months. The bleeding did not recur. No varicose veins were found in the esophagus and stomach during control endoscopic examinations. The patency of the splenorenal shunt was confirmed by ultrasound dopplerography.Conclusion. The first clinical experience of venous reconstruction with portosystemic bypass surgery using as a possible replacement of autologous vascular prostheses of the falciform ligament of the liver in the splenorenal position in a patient with portal hypertension syndrome in the outcome of cirrhosis of the liver of viral etiology gives hope for the possibility of further successful testing of this method of splenorenal bypass surgery to reduce the risk of bleeding from varicose veins.

Silk-based bilayered small diameter woven vascular conduits for improved mechanical and cellular characteristics

A major impediment to the development of small diameter vascular grafts is to achieve an optimal balance between its mechanical properties and cellular response. To address this, the technique of cylindrical weaving has been combined with electrospinning to fabricate a seamless bilayered conduit (∼3 mm) having an inner cell-friendly nanofibrous layer of poly(caprolactone)/collagen and an outer mechanically compliant woven silk layer. Mechanical characteristics such as burst strength, suture retention, compliance and leak resistance were found to be improved for this bilayered conduit when compared to the commercial standard. In-vitro studies revealed that the lumen of the conduit was non-hemolytic and could support adhesion and viability of endothelial cells. Overall, our studies suggest that the proposed bilayer construct could be a suitable candidate for small diameter vascular prosthesis.

Vascular Polyurethane Prostheses Modified with a Bioactive Coating-Physicochemical, Mechanical and Biological Properties.

This study describes a method for the modification of polyurethane small-diameter (5 mm) vascular prostheses obtained with the phase inversion method. The modification process involves two steps: the introduction of a linker (acrylic acid) and a peptide (REDV and YIGSR). FTIR and XPS analysis confirmed the process of chemical modification. The obtained prostheses had a porosity of approx. 60%, Young’s Modulus in the range of 9–11 MPa, and a water contact angle around 40°. Endothelial (EC) and smooth muscle (SMC) cell co-culture showed that the surfaces modified with peptides increase the adhesion of ECs. At the same time, SMCs adhesion was low both on unmodified and peptide-modified surfaces. Analysis of blood-materials interaction showed high hemocompatibility of obtained materials. The whole blood clotting time assay showed differences in the amount of free hemoglobin present in blood contacted with different materials. It can be concluded that the peptide coating increased the hemocompatibility of the surface by increasing ECs adhesion and, at the same time, decreasing platelet adhesion. When comparing both types of peptide coatings, more promising results were obtained for the surfaces coated with the YISGR than REDV-coated prostheses.

КЛИНИКО-ДЕМОГРАФИЧЕСКАЯ ХАРАКТЕРИСТИКА ПАЦИЕНТОВ И ФАКТОРЫ РИСКА ИНФИЦИРОВАНИЯ ИСКУССТВЕННЫХ СОСУДИСТЫХ ПРОТЕЗОВ ПОСЛЕ РЕКОНСТРУКТИВНЫХ ОПЕРАЦИЙ НА АОРТО-ПОДВЗДОШНО-БЕДРЕННОМ СЕГМЕНТЕ

Objective: to study the clinical and demographic characteristics of patients and risk factors, to analyze their influence on the frequency of infection of artificial vascular prostheses in the aortoiliac-femoral segment. Material and methods. We analyzed 609 medical records of inpatient patients who had undergone vascular reconstructive interventions on the aortoiliac-femoral segment using a synthetic vascular prosthesis. The article presents the clinical and demographic characteristics of patients with lesions of the aortoiliac-femoral segment. The frequency of conduit infection in various major diseases, surgical approaches, types of bypass surgery (prosthetics), types of artificial vascular prosthesis was analysed. Results. The patients who developed lesions of the aortoiliac-femoral segment were mostly males (94.6%), urban residents (78%), unemployed (68.6%), those with chronic obliterating diseases of the arteries of the lower extremities (72.7%) and coronary heart disease (59.4%). The incidence of vascular prostheses in patients with chronic obliterating diseases of the arteries of the lower extremities was 5.5%, and in those with an aneurysm of the infrarenal abdominal aorta – 1.2%. Conclusion. The pattern of developing artificial vascular prosthesis infection has been established. Infection of conduits occurs statistically significantly more often in patients with chronic obliterating diseases of the arteries of the lower extremities than in those with an aneurysm of the infrarenal abdominal aorta.

In vivo performance of electrospun tubular hyaluronic acid/collagen nanofibrous scaffolds for vascular reconstruction in the rabbit model

One of the main challenges of tissue-engineered vascular prostheses is restenosis due to intimal hyperplasia. The aim of this study is to develop a material for scaffolds able to support cell growth while tolerating physiological conditions and maintaining the patency of carotid artery model. Tubular hyaluronic acid (HA)-functionalized collagen nanofibrous composite scaffolds were prepared by sequential electrospinning method. The tubular composite scaffold has well-controlled biophysical and biochemical signals, providing a good matrix for the adhesion and proliferation of vascular endothelial cells (ECs), but resisting to platelets adhesion when exposed to blood. Carotid artery replacement experiment from 6-week rabbits showed that the HA/collagen nanofibrous composite scaffold grafts with endothelialization on the luminal surface could maintain vascular patency. At retrieval, the composite scaffold maintained good structural integrity and had comparable mechanical strength as the native artery. This study indicating that electrospun scaffolds combined with cells may become an alternative to prosthetic grafts for vascular reconstruction.Graphical

Q Fever Vertebral Osteomyelitis Complicating Vertebroplasty.

Query (Q) fever is a zoonotic bacterial infection caused by Coxiella burnetii. In a minority of patients, chronic disease can occur after acute infection. Endocarditis and infections of aneurysms or vascular prostheses are the most common forms of chronic Q fever in adults. We report a case of an elderly female patient with chronic Q fever vertebral osteomyelitis at the site of her previous cement vertebroplasty, complicated by paravertebral abscess. Patient treatment required prolonged drainage in addition to the long duration of antibiotic treatment by doxycycline and hydroxychloroquine. Osteomyelitis is a rare clinical presentation in adults with chronic Q fever. However, it is important to consider Q fever in the differential diagnosis of culture-negative osteomyelitis, especially in countries where C. burnetii is endemic, such as Israel.

Aortic arch reconstruction in the Norwood procedure using a curved polytetrafluorethylene patch.

The aortic arch enlargement in the Norwood procedure is classically carried out using a curved homograft patch on the inner curvature of the neoaortic arch. The study investigates the outcome of a newly used artificial patch from a vascular prosthesis as an alternative to a homograft patch. Since April 2007, we used curved polytetrafluorethylene (PTFE) patches cut out of a prosthesis as an alternative to homograft patches for the aortic arch reconstruction. The decision for either patch material was made due to anatomic reasons, preferring PTFE patches in larger aortas. In this study, 224 Norwood patients, operated between April 2007 and April 2018, were analysed. A total of 104 patients received a PTFE patch (group PTFE), and 120 patients got a pulmonary homograft patch (group homograft). A single-centre retrospective analysis was carried out concerning postoperative course and long-term follow-up regarding aortic arch interventions and reoperations and comparing the 2 material groups. There were no material associated operative or postoperative complications. In-hospital mortality was 13% in group PTFE. Six children died late during follow-up (6%). One aortic isthmus dilatation (1%) was carried out 12 months after the Norwood procedure in this group, no arch reoperation was necessary during the complete follow-up. The curved PTFE patch showed good qualities in operative technical demands and excellent long-term results. In selected cases of hypoplastic left heart syndrome, it can be well used as alternative to the pulmonary homograft.