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Three-dimensional printing has emerged as a promising technology in endovascular surgery for the production of patient-specific stent-grafts. Thermoplastic polyurethane (TPU) is widely used for this purpose due to its favourable biocompatibility, hemocompatibility, and mechanical properties. However, its long-term stability under physiological conditions remains uncertain. This study evaluates the ageing behaviour of 3D-printed TPU stent-grafts under accelerated oxidative conditions (20% H2O2–0.1 M CoCl2) over three months, corresponding to approximately 45 months in vivo, and during three months in hydrolytic (0.1 M NaOH) conditions. Mechanical, physicochemical, thermal, and surface properties were periodically analysed. Differential scanning calorimetry revealed a decrease in crystallisation enthalpy of 41% and a reduction in melting enthalpy of 29% after hydrolytic ageing, whereas no decrease was observed after oxidative ageing. Despite these chemical changes, size exclusion chromatography indicated minimal chain scission. However, spectroscopy and microscopy showed minor chain scission and additive migration (antioxidant and lubricant). Nevertheless, tensile testing highlighted that mechanical performance remained within clinically acceptable ranges. These findings demonstrate that 3D-printed TPU vascular implants retain essential properties under prolonged simulated ageing, supporting their safety and durability for vascular applications.

The biomaterial bacterial cellulose (BC) represents an innovative approach for overcoming reconstructive problems associated with extended vascular diseases by providing small caliber vascular grafts (diameter 1.0-3.7, length 5.0-10.0, and wall-thickness 0.7 mm). In a first microsurgical study, the BC implants were attached in an artificial defect of the carotid artery of rats for 1 year. These long term results show the incorporation of the BC under formation of neointima and ingrowth of active fibroblasts. In a second study, the grafts were used to replace the carotid arteries of pigs. After 3 months, these grafts were removed and analyzed both macro- and microscopically. Seven grafts (87.5%) were patent whereas one graft was found occluded. These data indicate that the innovative BC engineering technique results in the production of stable vascular conduits and confirm a highly attractive approach to in vivo tissue engineered blood vessels as part of programs in cardiovascular surgery.

Vascular stent is viewed as one of the greatest advancements in interventional cardiology. However, current approved stents suffer from in-stent restenosis associated with neointimal hyperplasia or stent thrombosis. Herein, we develop a nitric oxide-eluting (NOE) hydrogel coating for vascular stents inspired by the biological functions of nitric oxide for cardiovascular system. Our NOE hydrogel is mechanically tough and could selectively facilitate the adhesion of endothelial cells. Besides, it is non-thrombotic and capable of inhibiting smooth muscle cells. Transcriptome analysis unravels the NOE hydrogel could modulate the inflammatory response and induce the relaxation of smooth muscle cells. In vivo study further demonstrates vascular stents coated with it promote rapid restoration of native endothelium, and persistently suppress inflammation and neointimal hyperplasia in both leporine and swine models. We expect such NOE hydrogel will open an avenue to the surface engineering of vascular implants for better clinical outcomes. Neointimal hyperplasia and stent thrombosis remain issues with vascular stents. Here, the authors report on the development of a nitric oxide releasing hydrogel which allows for endothelialisation of the stent surface and prevents smooth muscle cell growth reducing hyperplasia and thrombosis in in vivo models.

We compared association of Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa and Enterococcus faecalis with nine vascular implants after co-culture. Vascular implants were composed of various materials such as warp knitted polyester (with or without gelatin and silver ions), expanded polytetrafluoroethylene and biological materials – surface treated porcine pericardial patch and Omniflow II. The lowest overall number of associated bacteria was detected for polytetrafluoroethylene implants and porcine pericardial patch. The highest overall number of associated bacteria was detected for Omniflow II implant. The major source of variation, i.e. primary factor influencing colonization, is the implant type (56.22%), bacterial species is responsible for only 1.81%, and interaction of those two factors – 13.09% of variation.

Cardiovascular diseases (CVD) are the leading cause of morbidity and mortality in the western world. In the last three decades, fluid dynamics investigations have been an important component in the study of the cardiovascular system and CVD. A large proportion of studies have been restricted to computational fluid dynamic (CFD) modeling of blood flow. However, with the development of flow measurement techniques such as particle image velocimetry (PIV), and recent advances in additive manufacturing, experimental investigation of such flow systems has become of interest to validate CFD studies, testing vascular implants and using the data for therapeutic procedures. This article reviews the technical aspects of in-vitro arterial flow measurement with the focus on PIV. CAD modeling of geometries and rapid prototyping of molds has been reviewed. Different processes of casting rigid and compliant models for experimental analysis have been reviewed and the accuracy of construction of each method has been compared. A review of refractive index matching and blood mimicking flow circuits is also provided. Methodologies and results of the most influential experimental studies are compared to elucidate the benefits, accuracy and limitations of each method.

Maximizing the re-endothelialization of vascular implants such as prostheses or stents has the potential to significantly improve their long-term performance. Endothelial progenitor cell capture stents with surface-immobilized antibodies show significantly improved endothelialization in the clinic. However, most current antibody-based stent surface modification strategies rely on antibody adsorption or direct conjugation via amino or carboxyl groups which leads to poor control over antibody surface concentration and/or molecular orientation, and ultimately bioavailability for cell capture. Here, we assess the utility of a bioaffinity-based surface modification strategy to immobilize antibodies targeting endothelial cell surface antigens. A cysteine-tagged truncated protein G polypeptide containing three Fc-binding domains was conjugated onto aminated polystyrene substrates via a bi-functional linking arm, followed by antibody immobilization. Different IgG antibodies were successfully immobilized on the protein G-modified surfaces. Covalent grafting of the protein G polypeptide was more effective than surface adsorption in immobilizing antibodies at high density based on fluorophore-labeled secondary antibody detection, as well as endothelial colony-forming cell capture through anti-CD144 antibodies. This work presents a potential avenue for enhancing the performance of cell capture strategies by using covalent grafting of protein G polypeptides to immobilize IgG antibodies.

Tricuspid repair is recommended for significant functional tricuspid regurgitation (FTR) or tricuspid annulus (TA) dilation, based on TA >40 mm or >21 mm/m². The concordance between both TA dimensions related to the patient's body size has not been investigated. Patients who underwent rigid ring tricuspid annuloplasty for FTR between 2009 and 2017 were included. Assuming equality between both TA diameter criteria, patients were divided per body surface area (BSA): group 1 = BSA ≤1.9 m² and group 2 = BSA >1.9 m². The primary outcome was TR recurrence at 5 years. Tricuspid annuloplasty was performed in 186 patients (group 1: 130 patients [69.9%]; group 2: 56 patients [30.1%]). Group 1 comprised more female (70.8% to 23.2%, p <0.001) and older patients (77.1 ± 9.3 years; 74.2 ± 8.2 years, p = 0.048). Group 1 had a smaller absolute TA diameter (group 1: 45.3 ± 5.2 mm; group 2: 48.2 ± 5.6 mm, p <0.001), whereas the indexed TA size was inversely higher (group 1: 26.3 ± 3.4 mm/m²; group 2: 24.2 ± 2.7 mm/m², p <0.001). The tenting height was comparable (group 1: 7.8 ± 3.0 mm; group 2: 8.0 ± 2.7 mm, p = 0.714). The median ring size was 30 (interquartile range 28 to 32) and 32 (interquartile range 30 to 34) for groups 1 and 2, respectively (p <0.001). TR recurrence at 5 years was noticed in 20.2% and 6.5% of group 1 and 2 (p = 0.035). Indexed TA diameter (hazard ratio 1.43, 95% confidence interval 1.10 to 1.87, p = 0.008) and tenting height (hazard ratio 5.52, 95% confidence interval 1.87 to 14.57, p = 0.002) were independent predictors of TR recurrence. In conclusion, when the absolute TA diameter is used as the primary criterion, smaller patients are at a higher risk for TR recurrence by having a proportionally larger TA at the time of repair. An individualized approach guided by patient's body size might be more appropriate to indicate FTR correction to adjust for the annuloplasty sizing method.

Cardiovascular diseases are one of the main causes of mortality in the modern world. Scientist all around the world are trying to improve medical treatment, but the success of the treatment significantly depends on the stage of disease progression. In the last phase of disease, the treatment is possible only by implantation of artificial graft. Most commonly used materials for artificial grafts are polymer materials. Despite different industrial procedures for graft fabrication, their properties are still not optimal. Grafts with small diameters (<6 mm) are the most problematic, because the platelets are more likely to re-adhere. This causes thrombus formation. Recent findings indicate that platelet adhesion is primarily influenced by blood plasma proteins that adsorb to the surface immediately after contact of a synthetic material with blood. Fibrinogen is a key blood protein responsible for the mechanisms of activation, adhesion and aggregation of platelets. Plasma treatment is considered as one of the promising methods for improving hemocompatibility of synthetic materials. Another method is endothelialization of materials with Human Umbilical Vein Endothelial cells, thus forming a uniform layer of endothelial cells on the surface. Extensive literature review led to the conclusion that in this area, despite numerous studies there are no available standardized methods for testing the hemocompatibility of biomaterials. In this review paper, the most promising methods to gain biocompatibility of synthetic materials are reported; several hypotheses to explain the improvement in hemocompatibility of plasma treated polymer surfaces are proposed.

Background: In patients with functional tricuspid valve regurgitation, there is debate over the relative efficacy of suture annuloplasty versus prosthetic rings for tricuspid valve (TV) repair. In this study, we compared the effectiveness of De Vega tricuspid valve repair versus tricuspid ring annulopalsty in patients with functional tricuspid valve regurgitation. Materials and Methods: From 2017 to 2019, we examined patients who had tricuspid valve repair and left sided valve surgery who had also undergone TV repair with suture (De Vega) or flexible ring annuloplasties. Patients having tricuspid valve endocarditis or trivial or mild functional tricuspid regurgitation were excluded. Primary early results, mortality, and postoperative TR grade were noted. Results: There were 150 patients in the total trial, ranging in age from 33 to 55 years. There was no discernible difference between the two groups in the overall cohort's elevated CTR, which suggested cardiomegaly in all of the investigated individuals. Ejection fraction (EF), which varied between 48 and 71% in each group, was determined to be statistically insignificant between the two groups. Mortality was predicted by advanced age, diabetes, and right ventricular failure before surgery. The longevity of the annuloplasty techniques was comparable, and the pattern of recurrent TR grades over follow-up was not significantly different. The early CTR decrease and EF raise exhibited a high level of statistical significance (p0.01) in both groups at discharge and the first postoperative follow-up. In the early postoperative period, 4% of patients experienced significant recurrent TR; however, 100% of patients who underwent ring annuloplasty and 92% of patients who underwent De Vaga's annuloplasty did not experience even mild TR. Otherwise, there was no preoperative, intraoperative, or early postoperative outcome statistically different between the De Vega annuloplasty group (A) and the ring annuloplasty group (B). Conclusions: In terms of the frequency of TR recurrence, there is strong evidence favouring ring annuloplasty over De Vega's annuloplasty. The use of ring annuloplasty for moderate to severe TR is superior than De Vega's annnuloplasty in terms of both long-term mortality and the frequency of TR recurrence resulting to reoperation

It has been suggested that the disparity of outcomes between the studies of transcutaneous edge-to-edge repair (TEER) for functional mitral regurgitation (FMR) in heart failure with reduced ejection fraction (HFrEF) could be due to systematic differences in the populations studied. One proposal is that there are 2 broad groups: those with proportional FMR who respond less favorably, and those in whom the FMR is greater than expected (disproportionate) FMR where edge-to-edge TEER seems to be more effective. Whether this grouping is relevant for other percutaneous interventions for FMR is unknown. We sought to compare clinical and echocardiographic outcomes of patients with HFrEF and proportionate and disproportionate FMR treated with indirect annuloplasty using the Carillon device. This is a pooled analysis from 3 trials of patients with FMR. Key patient eligibility in these trials specified persistent grade 2+ to 4+ FMR with >5.5 cm left ventricular (LV) end-diastolic diameter (LVEDD) and reduced ejection fraction. Patients with an effective regurgitant orifice area/LV end-diastolic volume (EROA/LVEDV) ratio under 0.15 were assigned to the proportionate FMR group (n = 74;65%) and those with a ratio above 0.15 were classed as having disproportionate FMR (n = 39;35%). At 12 months following treatment, both groups showed improvements in all MR variables including regurgitation volume, EROA and vena contracta. Moreover, in patients with proportionate MR there were clinically relevant and statistically significant improvements in LV volumes and diameters. There was no independent relationship between the degree of proportionality as a continuous variable and the remodeling response to Carillon therapy (change in LVEDV r = 0.17; change in LVESV r = 0.14). Percutaneous mitral annuloplasty with the Carillon device reduces MR in patients with both proportionate and disproportionate FMR, and also results in LV reverse remodeling in those with proportionate FMR. The effect on remodeling remains to be verified in a large-scale trial. [Display omitted]