Small diameter vascular grafts (SDVGs) are associated with a high failure rate due to poor endothelialization. The incorporation of a nitric oxide (NO) releasing system improves biocompatibility by ...using the NO effect to promote endothelial cell (EC) migration and proliferation while preventing bacterial infection. To circumvent the instability of NO donors and to prolong NO releasing, S-nitroso-N-acetyl-D-penicillamine (SNAP) as a NO donor was loaded in multi-walled carbon nanotubes (MWCNTs). Successful loading was confirmed with a maximum SNAP amount of ~ 5% (w/w) by TEM, CHNS analysis and FTIR spectra. SDVGs were 3D printed from polycaprolactone (PCL) and coated with a 1:1 ratio of polyethylene glycol and PCL dopped with different concentrations of SNAP-loaded matrix and combinations of MWCNTs-OH. Coating with 10% (w/w) SNAP-matrix-10% (w/w) SNAP-MWCNT-OH showed a diminished burst release and 18 days of NO release in the range of 0.5-4 × 10
mol cm
min
similar to the NO release from healthy endothelium. NO-releasing SDVGs were cytocompatible, significantly enhanced EC proliferation and migration and diminished bacterial viability. The newly developed SNAP-loaded MWCNT-OH has a great potential to develop NO releasing biomaterials with a prolonged, controlled NO release promoting in-situ endothelialization and tissue integration in vivo, even as an approach towards personalized medicine.
Introduction
Results and outcomes of ductus arteriosus stenting vary widely. The aim of this study was to determine whether ductus morphology is associated with different procedural outcome.
Methods
...Over an 18‐year period, 123 patients presented with ductal dependent pulmonary blood flow. Results were retrospectively assessed based on radiographic anatomic features of the ductus arteriosus: Group 1: “straight” ductus arteriosus, typically seen in patients with Pulmonary atresia with intact septum (PA‐IVS), Group 2: “intermediate” ductus arteriosus as seen in severe pulmonary stenosis (PS)‐single ventricle, Group 3: “vertical” ductus arteriosus typically seen in patients with pulmonary atresia‐ventricular septal defect, Group 4: ductus arteriosus arising from the aorta to a single lung, Group 5: ductus arteriosus arising from the innominate/subclavian artery to a single lung, Group 6: ductus arteriosus from innominate/subclavian artery to both lungs.
Results
Ductal stenting (DS) was attempted in 98 patients with 99 ducts. Successful stenting was possible in 83 patients. Success of DS was significantly different among the groups (p = .04, F = 5.41). Groups 1, 4, and 5 were “easy” with good success while Groups 2, 3, and 6 were complex and demanding. There were two deaths (after 5 and 7 days, respectively) that could be ascribed to DS. Elective re‐interventions were performed in 34 ductuses (40%). Fifty three percent (n = 44/83) of successful ductus stents proceeded to further surgery and 20 ducts closed spontaneously in asymptomatic patients over time.
Conclusions
Ductus arteriosus morphology influences technique and determines complexity, safety, and final outcome of ductus arteriosus stenting.
Adhesion of Staphylococcus aureus to blood vessels under shear stress requires von Willebrand factor (VWF). Several bacterial factors have been proposed to interact with VWF, including VWF-binding ...protein (vWbp), a secreted coagulase that activates the host's prothrombin to generate fibrin. We measured the adhesion of S aureus Newman and a vWbp-deficient mutant (vwb) to VWF, collagen, and activated endothelial cells in a microparallel flow chamber. In vivo adhesion of S aureus was evaluated in the mesenteric circulation of wild-type (WT) and VWF-deficient mice. We found a shear-dependent increase in adhesion of S aureus to the (sub)endothelium that was dependent on interactions between vWbp and the A1-domain of VWF. Adhesion was further enhanced by coagulase-mediated fibrin formation that clustered bacteria and recruited platelets into bacterial microthrombi. In vivo, deficiency of vWbp or VWF as well as inhibition of coagulase activity reduced S aureus adhesion. We conclude that vWbp contributes to vascular adhesion of S aureus through 2 independent mechanisms: shear-mediated binding to VWF and activation of prothrombin to form S aureus–fibrin–platelet aggregates.
•vWbp mediates adhesion of S aureus under flow to activated endothelial cells and the subendothelium via VWF.•vWbp activates prothrombin and triggers the formation of bacteria–fibrin–platelet aggregates, which enhance adhesion to vessels under flow.
Smart materials are able to react to different stimuli and adapt their shape to the environment. Although the development of 3D printing technology increased the reproducibility and accuracy of ...scaffold fabrication, 3D printed scaffolds can still be further improved to resemble the native anatomy. 4D printing is an innovative fabrication approach combining 3D printing and smart materials, also known as stimuli-responsive materials. Especially for cardiovascular implants, 4D printing can promisingly create programmable, adaptable prostheses, which facilitates implantation and/or create the topology of the target tissue post implantation. In this review, the principles of 4D printing with a focus on the applied stimuli are explained and the underlying 3D printing technologies are presented. Then, according to the type of stimulus, recent applications of 4D printing in constructing smart cardiovascular implants and future perspectives are discussed.
Idiopathic pulmonary arterial hypertension (IPAH) is an uncommon and severe disease. We report the case of a 7-year-old boy investigated for cardiac murmur and exercise intolerance. Pulmonary ...hypertension (PH) was suspected at clinical examination and confirmed by echocardiography and cardiac catheterization. This case of pulmonary hypertension was classified as idiopathic given the negative etiological investigation. Vasoreactive testing with oxygen and nitric oxide was negative. Therefore, treatment with sildenafil (1.4 mg/kg/d) and bosentan (3 mg/kg/d) was initiated. This allowed the stabilization of, but not a decrease in, pulmonary artery pressure for the next 5 years, during which the patient's quality of life was significantly reduced. At a later follow-up, the estimated pulmonary pressure was found to have increased and become supra-systemic, with a consequent deterioration in the child's condition. This led to the decision to enter him into a clinical trial that is still ongoing. Idiopathic pulmonary arterial hypertension is a severe disease that can present with non-specific symptoms, such as asthenia and exercise limitation, which are important not to trivialize. The disease is associated with significantly decreased quality of life in affected children and carries a high burden in terms of mortality and morbidity. The current knowledge about IPAH in children is reviewed, with a particular focus on the future prospects for its treatment and the related quality of life of patients.
Abstract Objective Various conduits or stent-mounted valves are used as pulmonary valve graft tissues for Right Ventricular Outflow Tract reconstruction with good hemodynamic results. Valve ...replacement inherits an increased risk of infective endocarditis (IE). Recent observations rose awareness to IE after transcatheter implantation of a stent-mounted bovine jugular vein valve. The present study focuses on the susceptibility of graft tissue surfaces to bacterial adherence as a potential risk factor for subsequent IE. Methods Staphylococcus aureus , S. epidermidis and Streptococcus sanguinis adhesion to bovine pericardium (BP) patch, bovine jugular vein (BJV) and cryopreserved homograft (CH) tissues was quantified under static and shear stress conditions. Microscopic analysis and histology were performed to evaluate bacterial adhesion to matrix components. Results In general, similar bacteria numbers were recovered from CH and BJV tissue surface for all strains, especially in flow conditions. Static bacterial adhesion to CH wall was lower for S. sanguinis adhesion ( P <0.05 vs. BP patch). Adhesion to BJV wall, CH wall and leaflet were found to be decreased for S. epidermidis in static conditions ( P <0.05 vs. BP patch). Bacterial adhesion under shear stress indicates a similar bacterial adhesion to all tissues, except for a decrease to BJV wall after S. sanguinis incubation. Microscopic analysis shows the importance of matrix component exposure for bacterial adherence to CH. Conclusions Our data exhibit evidence that the surface composition of BJV and CH tissues itself, bacterial surface proteins or shear forces per se are not the prime determinants during initial bacterial adherence.
a Paediatric and Congenital Cardiology, University Hospitals Leuven, Belgium
b Paediatric Cardiology, University of the Free State, South Africa
*Corresponding author. University Hospital ...Gasthuisberg, Herestraat 49, B 3000 Leuven, Belgium. Tel.: +32 16 343865; fax: +32 16 343981. E-mail address : marc.gewillig{at}uzleuven.be (M. Gewillig).
In a Fontan circuit the mechanisms involved in control of cardiac output at rest and during exercise differ significantly from normal. The classical model presumes an unlimited preload which is not available in the Fontan circuit. This review critically analyses the role of contractility, heart rate, and afterload and highlights the importance of pulmonary vascular resistance (PVR) in determining adequate preload and, therefore, cardiac output in these patients. A conceptual model of the determinants of cardiac output in Fontan patients is presented.
Key Words: Univentricular heart; Fontan circulation; Cavopulmonary connection; Cardiac output
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