Anti-thrombotic treatment enhances antibiotic efficiency in a humanized model of meningococcemia

Meningococcal infections remain particularly difficult to treat. Despite antibiotic therapy, the state of the patients often rapidly deteriorates. Early clinical studies suggest that meningococci acquire a form of resistance to antibiotic treatments during infections. Taking advantage of a humanized animal model of infection, we confirm that adherent bacteria become highly resistant to antibiotic treatments as early as 3-6 hours post infection, although fully sensitive in vitro. Within this time frame, meningococci adhere to the endothelium via their type IV pili, proliferate and eventually fill the vessel lumen. Using intravital imaging, we show that rapidly upon infection blood flow is dramatically decreased, thus limiting antibiotic access to infected vessels. Concomitantly, fibrin is deposited inside infected vessels in proximity to bacterial aggregates. Pharmacologically impairing thrombin generation by inhibiting Factor X activity not only improves blood flow in infected vessels, but also enhances the efficacy of the antibiotic treatment. Our results indicate that the combined administration of anticoagulants together with antibiotics might represent a therapeutic approach to treat meningococcal sepsis more efficiently.

Evaluation of Diagnostic Performance of MDCT Coronary Angiography in Comparison with Conventional Coronary Angiography

Background: Coronary artery disease is now becoming increasingly prevalent than before especially in younger age groups. We in the current study tried to evaluate the potential of 128 slice MDCT coronary angiography for the detection of stenotic coronary lesions by comparing the results of computed tomographic coronary angiography to a gold standard set by Conventional coronary angiography. Methods: A total of n=30 patients with clinically suspected Coronary artery disease. They were evaluated with 128 Slice CT Scanner (PHILIPS INGENUITY) and conventional coronary angiography. All patients were examined with a 128 slice MDCT scanner (Philips Ingenuity 128 slice Netherlands) using standard cardiac CT protocol. Gantry rotation time was 400 ms with a half sector acquisition protocol and multisector reconstruction permitting an effective temporal resolution between 50 and 200 ms depending on patient heart rate. Results: In the n=30 Patients included in the study with CCA, the n=450 coronary segments included in the study were found to contain a total number of n=138 stenoses among them non-significant stenoses. The accuracy of MDCT detection of coronary stenoses greater than 50% diameter of vessel lumen is about 94.78. When raising the threshold for stenosis from 50% to 70% of the vessel lumen, so that only hemodynamic relevant stenoses enter the evaluation, the sensitivity decreases from 88%. The MDCT detection in the patient group with heart rates below 60 beats per minute higher values for sensitivity 93% and specificity 97% were observed, compared to sensitivity 87% and specificity 93% of the patient group with heart rates above 60 beats per minute. Conclusion:The present study revealed that a high negative predictive value (98.08%)suggests that 128- Slice MDCT coronary angiography is a good screening modality for evaluation of patients with mild to intermediate-risk factors who might otherwise require invasive angiography.

High-Resolution MR for Follow-Up of Intracranial Steno-Occlusive Disease Treated by Endovascular Treatment

Background and Purpose: An endovascular recanalization is an alternative option for symptomatic intracranial atherosclerotic steno-occlusive disease (ICAD). Accurate non-invasive alternatives to digital subtraction angiography (DSA) for follow-up imaging after endovascular treatment are desirable. We aimed to evaluate the image quality and diagnostic performance of high-resolution magnetic imaging in follow-up using DSA as a reference.Materials and Methods: From January 2017 to June 2021, data from 35 patients with 40 intracranial steno-occlusive lesions who underwent endovascular recanalization and received high-resolution magnetic resonance (HR-MR) follow-up were retrospectively collected in our prospective database. Studies were evaluated for the quality of visualization of the vessel lumen, restenosis rate, and accuracy of high-resolution magnetic resonance (HR-MR) with DSA used as the reference standard. Intraclass correlation coefficient (ICC) analyses were performed to assess the agreement between the two different readers.Results: In total, 40 intracranial steno-occlusive lesions in 35 patients, with 34 lesions undergoing balloon angioplasty [including 16 drug-coated balloons (DCBs)] and 8 lesions undergoing stenting were enrolled. The median age was 63.6 years (IQR 58.5–70.0 years), and the mean imaging follow-up time was 9.5 months (IQR 4.8–12.5 months). The median degrees of preprocedural and residual stenosis were 85.0% (IQR 75.0–99.0%) and 32.8% (IQR 15.0–50.0%), respectively. Intracranial periprocedural complications occurred in 1 (3.6%) patient. In the case of a stainless-steel stent (n = 1), there was a signal drop at the level of the vessel, which did not allow evaluation of the vessel lumen. However, this was visible in the case of nitinol stents (n = 7) and angioplasty (n = 34). The overall restenosis rate was 25.8% (n = 9). The DCB subgroup showed a lower rate of restenosis than the percutaneous transluminal angioplasty (PTA) subgroup [5.3% (2/13) vs. 35.7% (5/14)].Conclusion: High-resolution magnetic resonance may be a reliable non-invasive method for demonstrating the vessel lumen and diagnostic follow-up after endovascular recanalization for ICAD. Compared with MR angiography (MRA), HR-MR showed a higher inter-reader agreement and could provide more information after endovascular recanalization, such as enhancement of the vessel wall.

Hillslope Processes Affect Vessel Lumen Area and Tree Dimensions

The height growth of the trees depends on sufficient mechanical support given by the stem and an effective hydraulic system. On unstable slopes, tree growth is affected by soil pressure from above and potential soil erosion from below the position of tree. The necessary stabilization is then provided by the production of mechanically stronger wood of reduced hydraulic conductivity. Unfortunately, the interaction between tree growth (both radial and axial) and stabilization in the soil is still insufficiently understood. Therefore, in this study, we aimed to quantify the impact of hillslope dynamics on the degree of tree growth and hydraulic limitation, and the potential effect on tree height growth and growth plasticity. To evaluate this effect, we took four cores from 80 individuals of Quercus robur and Fraxinus excelsior and measured tree-ring widths (TRWs) and vessel lumen areas (VLAs). The tree heights were evaluated using a terrestrial laser scanner, and local soil depth was measured by a soil auger. Our data showed a significant limitation of the tree hydraulic system related with the formation of eccentric tree-rings. The stem eccentricity decreased with increasing stem diameter, but at the same time, the negative effect of stem eccentricity on conduit size increased with the increasing stem diameter. Even though this anatomical adaptation associated with the effect of stem eccentricity differed between the tree species (mainly in the different degree of limitations in conduit size), the trees showed an increase in the proportion of hydraulically inactive wood elements and a lowered effectiveness of their hydraulic system. In addition, we observed a larger negative effect of stem eccentricity on VLA in Quercus. We conclude that the stabilization of a tree in unstable soil is accompanied by an inability to create sufficiently effective hydraulic system, resulting in severe height-growth limitation. This affects the accumulation of aboveground biomass and carbon sequestration.

Use and effectiveness of Pioneer re-entry device for subintimal true lumen re-entry: single-centre data and a review of the literature

Introduction During subintimal angioplasty (SIA), it is not always possible to re-enter the vessel lumen due to a variety of factors. Recanalization using hydrophilic wires and catheters alone, apart from its potential technical failure, is also limited by minimal control over the re-entry point. This is frequently well beyond the point of occlusion, thus often compromising important collaterals. In order to bypass the obstruction and attain controlled re-entry into the lumen of the diseased vessel, a re-entry device (RED) may be required. This paper assesses our centre’s experience with the safety and efficacy of the Pioneer re-entry system and systematically reviews the pertinent literature. Method A single centre retrospective study of subintimal angioplasty involving the use of the Pioneer Plus intravascular guided reentry catheter was performed. Patient demographics including age, gender, risk factors, comorbidities clinical indication and complications were recorded. Lesion characteristics, including location and severity of calcification were also assessed. A systematic literature review of all reported studies where the Pioneer RED was used for iliac and lower limb revascularization was conducted by 2 of the authors using the PubMed (MEDLINE) and EMBASE databases. Results The study comprised 30 cases. Technical success was 97%. A small, quickly resolved extravasation was the only device related complication. These results are in line with the systematic review which identified 16 studies using the Pioneer RED, reporting a technical success rate of 87.4–100% (median = 100%) and complication rate of 0–25.8% (median = 0%). However, due to heterogeneity in definitions of technical success, data was not pooled.

Computer modeling of different shaped patches in classical carotid endarterectomy

Objective: to construct geometric models of carotid bifurcation and build a computer modeling for carotid endarterectomy (CEA) operations with patches of various configurations.Materials and methods. The method uses reconstructed models of a healthy blood vessel obtained from a preoperative computed tomography (CT) study of the affected blood vessel of a particular patient. Flow in the vessel is simulated by computational fluid dynamics using data from the patient's ultrasonic Doppler velocimetry and CT angiography. Risk factors are assessed by hemodynamic indices at the vessel wall associated with Wall Shear Stress (WSS).Results. We used the proposed method to study the hemodynamic results of 10 virtual CEA operations with patches of various shapes on a reconstructed healthy artery of a particular patient. The reason for patch implantation was to ensure that the vessel lumen is not narrowed as a result of the surgery, since closing the incision without a patch can reduce the vessel lumen circumference by 4–5 mm, which adversely affects blood flow. On the other hand, too wide a patch creates aneurysmorphic deformation of the internal carotid artery (ICA) mouth, which is not optimal due to formation of a large recirculation zone. In this case, it was found that the implanted patch width of about 3 mm provides an optimal hemodynamic outcome. Deviations from this median value, both upward and downward, impair hemodynamics. The absence of a patch gives the worst of the results considered.Conclusion: The proposed computer modeling technique is able to provide a personalized patch selection for classical CEA with low risk of restenosis in the long-term follow-up.

Biocompatibility and patency of a novel titanium vascular anastomotic device in a pig jugular vein

This study aimed to evaluate the biocompatibility and patency of our newly developed titanium vascular anastomotic device (TVAD) in a pig jugular vein. TVAD was made of commercially pure grade 2 titanium. The patency and anastomotic time were simultaneously confirmed in an ex-vivo system developed by the authors and in vivo using pig jugular veins. Five 8-month-old pigs, with body weights of 50–60 kg, underwent anastomosis of both jugular veins using the device. Graft patency was evaluated for 12 weeks by biplane angiography and sonography. All tissue biopsy samples were analysed by histology. In all 10 cases, the anastomosis was completed in < 5 min. The vessel lumen was not damaged, and the inner vessel wall was completely endothelialised at the anastomotic site. No foreign body reactions were observed at the vessel lumen, vessels, and outer vessel walls by histopathologic analysis. Patency and absence of leakage at the anastomotic site of the follow-up period were confirmed clearly by angiography and sonography. This preliminary animal study proved that our newly developed device is a very promising tool for intima-to-intima contact anastomosis. TVAD can be used as a feasible and safe medical tool for vessel anastomosis.

Iliac Pseudoaneurysm, Only a Manifestation With More Causes: A Case Report

Pseudoaneurysm is due to a disruption in arterial wall continuity. It forms a sac that communicates with the vessel lumen and is surrounded by the compressed, surrounding tissues and not by the wall of the artery from which the lesion arises. Many causes can predispose to the formation of a pseudoaneurysm such as trauma, surgical procedures, anticoagulation. In our patient another important risk factor for the formation of a pseudoaneurysm is ADPKD (autosomal dominant polycystic kidney disease) that can cause vascular complication. The mechanisms leading to the genesis of the pseudoaneurysms in our patient are unknown, but the clinicians should bear in mind when evaluating this type of patients that ADPKD may have a various range of systemic cardiovascular manifestation.

Multifocal vascular affection in a patient with angina pectoris - rationale and design of a clinical study

Atherosclerosis is a disease of the large and middle arteries and is characterized mainly by endothelial dysfunction, inflammation of the vascular wall and the accumulation of lipids, cholesterol, calcium and cell debris in the intima of the vascular wall. This accumulation leads to plaque formation, vascular remodeling, acute and chronic obstruction of the vessel lumen, blood flow abnormalities, and reduced oxygen supply to target organs. As a result, blood vessels become harder and their lumen shrinks, which increases the risk of obstruction and thrombosis. Depending on the affected area, the corresponding symptoms appear - angina or myocardial infarction when affecting the coronary circulation; transient ischemic attack (TIA) or stroke affecting cerebral circulation; claudication or gangrene when affecting the limbs; aneurysm or dissection affecting the aorta. Various risk factors are known to affect the onset of the disease. They are divided into adjustable (dyslipoproteinemia, hypertension, diabetes mellitus, smoking, obesity, inactivity, emotional stress, etc.) and unadjustable (gender, age, family predisposition). The risk of developing atherosclerosis increases significantly in the presence of several risk factors. For example, the presence of 2 risk factors increases the risk of developing atherosclerosis 4 times. The atherosclerotic process is multifocal - it develops everywhere in the body - affecting the cardiac, cerebral and peripheral arteries almost simultaneously or sequentially. Its isolated manifestations in only one area are an exception.