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

Objectives Autologous 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. Methods A 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. Results SEM 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. Conclusions The 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.

Tracheoarterial fistula as a complication of prolonged tracheostomy

The article presents a clinical case of a rare and severe complication of prolonged tracheostomy in the form of fistula formation between tracheal lumen and brachiocephalic artery and the development of massive bleeding from it. The patient’s treatment was urgent and successful. Operative intervention was performed with subsequent allografting of brachiocephalic trunk (vascular prosthesis Vascutek 8 mm was used) and the anastomosis was created using a continuous suture technique. The patient was discharged home in a satisfactory condition on the 17th post-operative day.

Perceval Implantation and Ascending Replacement: Which Should Be Performed First?

The use of sutureless prostheses has expanded due to their ability to reduce surgical times, thus favoring their implantation in high-risk patients. It is not uncommon that these patients have an ascending aortic aneurysm requiring treatment with a vascular prosthesis; therefore, using a sutureless aortic valve may be associated. To date, however, little is known about the time sequence of this intervention, that is, if sutureless implantation should precede or follow that of the vascular prosthesis.

Single-Stage Off-Pump Hybrid Repair of Kommerell's Diverticulum with Right-Sided Aortic Arch Using a Surgeon-Customized Vascular Prosthesis

We report the successful single-stage hybrid management of Kommerell's diverticulum associated with a right-sided aortic arch in a 63-year-old woman. She underwent total aortic arch debranching utilizing a surgeon-customized vascular prosthesis, without cardiopulmonary bypass or deep hypothermic circulatory arrest, and concomitant zone-0 endovascular stent–graft deployment.

Ascending aorta and aortic root replacement in an infant: a case report

<p>We herein report the first clinical case of prosthetic replacement of the ascending aorta and aortic arch to repair a giant aneurysm in a 7-month-old child. The ascending aorta and arch replacement to the level of left subclavian artery was performed using a no. 16 Polymaille prosthesis, the brachiocephalic trunk was reimplanted into the vascular prosthesis and the kinked section of the left common carotid artery was removed, followed by reimplanting the left common carotid artery into the left subclavian artery. First, proximal anastomosis with the vascular prosthesis was created using a no. 16 Polymaille prosthesis and the vascular suture was strengthened with a Teflon strip. During circulatory arrest, the aortic arch was crossed between the orifice of the left common carotid artery and left subclavian artery, with the cut extended to the isthmus region along the small curvature of the arch. The brachiocephalic trunk was aligned and brought down, with subsequent implantation into the ascending aorta prosthesis 2 cm below the initial fixation point. In the final stage, the kinked section of the left common carotid artery was resected and the aligned left carotid artery was directly reimplanted into the left subclavian artery using end-to-side anastomosis. The patient developed tracheobronchitis and moderate heart failure during the postoperative period. The duration of mechanical ventilation was 16 hours. Infusion and antibacterial therapy were discontinued on postoperative day 8. On postoperative day 13, the patient was discharged and referred to the outpatient centre for further treatment and rehabilitation. A sufficiently large-sized prosthesis allows for further development in paediatric patients. This is facilitated by the preservation of the native aortic root with restored valve function and the formation of a bevelled distal anastomosis with a small unchanged aortic section in the isthmus region, which maintains growth potential. This first reported case of an infant demonstrates the possibility of combination interventions on the aortic arch and brachiocephalic artery during the first year of life.</p><p>Received 30 January 2021. Revised 24 March 2021. Accepted 29 March 2021.</p><p><strong>Funding:</strong> The study did not have sponsorship.</p><p><strong>Conflict of interest:</strong> The authors declare no conflicts of interests.</p><p><strong>Contribution of the authors: </strong>The authors contributed equally to this article.</p>

Antimicrobial vascular grafts: experimental development and implementation in clinical practice

Prosthetic vascular graft infections, followed by severe complications and high mortality rates, remain one of the main issues in cardiovascular surgery. Therefore, the development of antimicrobial coating for vascular prostheses that is capable of preventing the infection is a very relevant field. This review outlines the main factors of development of antibiotic-resistant bacteria, the main directions in the development of vascular prostheses with an antimicrobial coating, and the prospects for the application of antimicrobial peptides and cationic amphiphiles as antimicrobial coating to develop an infection-resistant vascular prosthesis.

Development of personalized cell-populated vascular graft in vitro

Aim. To create a personalized cell-populated small-diameter vascular prosthesis in a pulsating bioreactor.Methods. Tubular grafts were made by electrospinning from mixtures of biodegradable polymers, poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(εcaprolactone) (PCL). The inner surface is modified with fibrin. Tubular scaffolds were colonized with cultured colony-forming endothelial cells and grown under static conditions for 2 days. Then, the cell-populated prostheses continued to be cultivated for 5 days in a pulsating bioreactor system with a final shear stress of 2.85 dynes/cm².Results. The advantages of the cultivation of cell-populated vascular prostheses in a pulsating bioreactor have been revealed. The selected mode of cultivation of cellpopulated vascular prostheses under conditions of a pulsating flow with a shear stress of 2.85 dynes/cm² did not have a damaging effect on the integrity of the endothelial monolayer. Moving unidirectional mechanical stimuli of chaotic orientation fibers of F-actin changed to a predominant orientation in the direction of flow, and also increased the expression of F-actin, Talin focal adhesion protein, and specific endothelial markers CD309, CD31, vWF.Conclusion. The creation of a personalized cell-populated small-diameter vascular prosthesis with a functional endothelial monolayer is possible due to the use of autologous endothelial cells, autologous fibrin, and cultivation under conditions of a pulsating flow.

The Influence of a Knitted Hydrophilic Prosthesis of Blood Vessels on the Activation of Coagulation System—In Vitro Study

The replacement of affected blood vessels of the polymer material can cause imbalances in the blood haemostatic system. Changes in blood after the implantation of vascular grafts depend not only on the chemical composition but also on the degree of surface wettability. The Dallon® H unsealed hydrophilic knitted vascular prosthesis double velour was assessed at work and compare with hydrophobic vascular prosthesis Dallon®. Spectrophotometric studies were performed in the infrared and differential scanning calorimetry, which confirmed the effectiveness of the process of modifying vascular prostheses. Determination of the parameters of coagulation time of blood after contact in vitro with Dallon® H vascular prosthesis was also carried out. Prolongation of activated thromboplastin time, decreased activity of factor XII, IX and VIII, were observed. The prolonged thrombin and fibrinogen were reduced in the initial period of the experiment. The activity of plasminogen and antithrombin III and protein C were at the level of control value. The observed changes in the values of determined parameters blood coagulation do not exceed the range of referential values for those indexes. The observed changes are the result of considerable blood absorptiveness by the prosthesis of blood vessels and their sealing.