Search Results (50)

Background/Objectives: Arteriovenous grafts (AVGs) are critical for hemodialysis access in patients with inadequate native vasculature. The Xeltis aXess graft, a novel bioresorbable vascular access conduit, promotes endogenous tissue restoration. While early outcomes have been promising, longer-term data remain limited. This report presents the longest reported, four-year follow-up on two of the first implanted aXess devices. Case Summaries: Case 1: A 64-year-old woman underwent aXess graft placement on 10 June 2021, between the right brachial artery and vein. She experienced graft thrombosis after 12 months and 18 months, both of which were successfully resolved with thrombectomy, in one instance in combination with drug-coated balloon (DCB) angioplasty. The graft remains functional. Case 2: A 76-year-old man received an aXess graft on 11 June 2021, in the left arm. After 6 months, he underwent balloon and DCB angioplasty for graft–vein (G–V) anastomosis stenosis. After 28 months, to resolve multiple pseudoaneurysms, followed by aneurysm resection and AVG reconstruction at month 29, a tunneled catheter was placed to perform dialysis sessions in the meantime. At month 44, graft-venous (G–V) angioplasty with DCB was performed to resolve G–V and axillary vein stenoses diagnosed at month 43. The graft remains in use. Results: Both patients retained functional dialysis access after four years, despite requiring multiple interventions for thrombosis, stenosis, and pseudoaneurysms. Conclusions: These cases demonstrate that the aXess graft can maintain functionality over four years with appropriate management, although close surveillance and reinterventions may be required. Full article

Background/Objectives: Heart failure (HF) causes systemic and regional haemodynamic alterations that extend beyond the heart, profoundly affecting splanchnic circulation. Venous congestion is a hallmark of heart failure (HF) and a major determinant of clinical deterioration and multiorgan dysfunction. The splanchnic venous system—comprising the portal, hepatic, and renal veins—acts as a key reservoir for intravascular volume redistribution. Conventional ultrasound (US), using grayscale and Doppler imaging, offers a direct, non-invasive approach to visualize these haemodynamic changes. This review, Part 1 of a two-part series, summarizes the current evidence and clinical applications of conventional US for assessing splanchnic, cardiac and pulmonary vascular alterations in patients with HF. Methods: A systematic review was performed in PubMed, Embase, and the Cochrane Library up to current date, following PRISMA 2020 guidelines. Eligible studies included adult human investigations evaluating splanchnic vascular changes in HF using B-mode, color Doppler, or pulsed Doppler ultrasonography. Exclusion criteria were pediatric, animal, or non-English studies and non-standard imaging methods. Data on ultrasonographic parameters, haemodynamic correlations, and prognostic value were extracted and qualitatively synthesized; Results: A total of 148 eligible studies (n ≈ 7000 patients) demonstrated consistent associations between HF severity and alterations in splanchnic, cardiac and pulmonary flow. Findings included increased bowel wall thickness, portal vein dilation with elevated pulsatility, and monophasic or reversed hepatic vein waveforms, all correlating with higher right atrial pressure and adverse clinical outcomes. The integration of these parameters into the Venous Excess Ultrasound (VExUS) framework enhanced detection of systemic venous congestion, in addition to the study of the cardiac and pulmonary circulation. Conclusions: Conventional ultrasound assessment of splanchnic vasculature provides valuable, reproducible insight into systemic congestion in HF. Incorporating hepatic and portal Doppler indices into standard evaluation protocols may improve risk stratification, optimize decongestion therapy, and guide management. Further prospective randomized and outcome-driven studies are required before VExUS-based therapeutic thresholds can be universally recommended and define prognostic thresholds. Full article

Acute pulmonary embolism (APE) remains a significant cause of mortality and morbidity despite increasing prophylaxis for deep venous thrombosis (DVT). The IVC filter is a temporary or permanent intravascular device that traps migrating thrombi from their origin in the pelvis or a lower limb into the pulmonary vasculature, thereby preventing significant APE. The current and longstanding indications for placing an IVC filter are in patients with documented lower extremity DVT and acute APE who also have absolute contraindications to anticoagulation or have experienced an acute, hemodynamically unstable APE requiring ventilatory and vasoactive support, with limited cardiovascular reserve. Updated guidelines have led to a significant rise in IVC filter placements for specific therapeutic indications of venous thromboembolism compared to prophylactic use. Meta-analyses show that IVC filter placement is associated with a lower risk of subsequent APE but an increased risk of DVT. However, there appears to be no significant reduction in APE-related mortality and no change in all-cause mortality. Early complications after IVC filter placement typically relate to procedural issues and include bleeding or infection at the venous access site, development of arteriovenous fistulas, accidental arterial puncture, and post-procedural access site hematoma or thrombosis. Additional early complications include IVC filter malposition, incomplete expansion, IVC penetration, or guidewire entrapment. Delayed complications may involve DVT below the filter, IVC occlusion due to the filter, IVC filter migration, fracture of one of the IVC filter components, IVC rupture, or IVC thrombosis. Retrieval of IVC filters by simple, advanced, or open techniques should be considered after weighing the risk-to-benefit for the individual patient. Deployment of the IVC filter remains an important component of interventional APE management within the narrow indications currently proposed. Current guidance recommends that an untethered temporary IVC filter should be placed and retrieved once the contraindication to anticoagulation is resolved. Full article

Background: Calvarial venous malformations (VMs) are rare and genetically understudied. While somatic TEK receptor tyrosine kinase (TEK) mutations drive sporadic VMs, their role in scalp–calvarial VMs is unknown. We report the first pediatric case of a calvarial VM with a pathogenic somatic TEK mutation and its molecular implications. Methods: A 16-year-old female with a symptomatic parietal scalp VM underwent neurosurgical resection. Exome sequencing was performed on both lesional and blood DNA. Single-cell RNA sequencing (scRNA-seq) data from normal brain vasculature were analyzed for TEK expression and pathway enrichment. Results: A novel somatic TEK L914F mutation (chr9:27212760-C-T [GRCh38]), absent in germline DNA and population databases, was identified and predicted to be deleterious (CADD: 24). scRNA-seq data analysis revealed TEK enrichment in endothelial cells, particularly in fetal and arterial subtypes, and implicated angiogenesis and PI3K/Rho signaling as potential downstream phenotypic and molecular consequences. Conclusions: This first pediatric scalp VM with a somatic TEK L914F mutation expands the phenotypes associated with TEK-related vascular anomalies. These findings emphasize the role of somatic TEK mutation in diverse VMs and support genetic testing in sporadic cases. Further studies are needed to define therapeutic targets. Full article

Background: Vascular malformations are relatively common in children. Current therapeutic strategies include observation, medical therapy, sclerotherapy or embolization, laser therapy, cryoablation, and surgery, depending on the type and anatomical location of the malformation. Surgery is commonly limited to small and/or circumscribed lesions, to debulking in case of large volumes, or in drug-resistant cases. Sclerotherapy is a minimally invasive treatment generally used to treat dysplastic vasculature and to significantly improve patients’ symptoms. Herein, we describe our preliminary experience with bleomycin electrosclerotherapy (BEST) in the treatment of peripheral low-flow venous and lymphatic malformations in the pediatric population. Methods: We prospectively collected and analyzed data from patients who underwent BEST for peripheral low-flow vascular malformations (venous and lymphatic) and were treated at our institution from May 2022 onward. Results: Twelve patients (4 boys and 8 girls) with peripheral low-flow vascular malformations who underwent BEST were enrolled in this preliminary study. The median patient age at the first procedure was 81 months (IQR = 46–128). The most frequent anomaly was peripheral low-flow venous malformation. No relevant postoperative complications were encountered in any of the patients. All patients underwent a clinical evaluation of the malformation 1 month after the procedure. A clinical and ultrasonographic evaluation of the malformation was performed 2 months after the procedure to determine whether to repeat BEST. In cases of clinical resolution, a second ultrasonographic evaluation was performed 6 months after the procedure. Conclusions: BEST appears to be a promising and safe option for treating peripheral low-flow vascular malformations in children. Further studies with a greater number of patients and longer follow-up periods are needed to confirm our preliminary experience. Full article

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare, progressive form of pre-capillary pulmonary hypertension characterized by persistent, organized thromboemboli in the pulmonary vasculature, leading to vascular remodeling, elevated pulmonary artery pressures, right heart failure, and significant morbidity and mortality if untreated. Despite advances, CTEPH remains underdiagnosed due to nonspecific symptoms and overlapping features with other forms of pulmonary hypertension. Basic Methodology: This review synthesizes data from large international registries, epidemiologic studies, translational research, and multicenter clinical trials. Key methodologies include analysis of registry data to assess incidence and risk factors, histopathological examination of lung specimens, and molecular studies investigating endothelial dysfunction and inflammatory pathways. Diagnostic modalities and treatment outcomes are evaluated through observational studies and randomized controlled trials. Recent Advances and Affected Population: Research has elucidated that CTEPH arises from incomplete resolution of pulmonary emboli, with subsequent fibrotic transformation mediated by dysregulated TGF-β/TGFBI signaling, endothelial dysfunction, and chronic inflammation. Affected populations are typically older adults, often with prior venous thromboembolism, splenectomy, or prothrombotic conditions, though up to 25% have no history of acute PE. The disease burden is substantial, with delayed diagnosis contributing to worse outcomes and higher societal costs. Microvascular arteriopathy and PAH-like lesions in non-occluded vessels further complicate the clinical picture. Conclusions: CTEPH is now recognized as a treatable disease, with multimodal therapies—surgical endarterectomy, balloon pulmonary angioplasty, and targeted pharmacotherapy—significantly improving survival and quality of life. Ongoing research into molecular mechanisms and biomarker-driven diagnostics promises earlier identification and more personalized management. Multidisciplinary care and continued translational investigation are essential to further reduce mortality and optimize outcomes for this complex patient population. Full article

Background: Arterial variations in the upper limb, although infrequent, carry critical clinical implications. The presence of superficial ulnar and radial arteries, especially when originating from high levels, increases the risk of iatrogenic injury, misdiagnosis, and surgical complications. To confirm and describe, through ultrasound and anatomical dissection, the presence of a high-origin superficial ulnar artery and a superficial radial artery in a cadaver, highlighting their anatomical trajectory and clinical relevance. Methods: A cross-sectional ultrasound and anatomical study was conducted on 150 upper limbs from fresh-frozen cadavers. High-frequency ultrasound was used to scan the vasculature from the axilla to the wrist. Subsequently, dissection was performed to confirm sonographic findings. Results: One case (0.66%) of concurrent superficial ulnar artery and superficial radial artery was identified in the left arm of a 79-year-old male cadaver. The superficial ulnar artery originated from the axillary artery and coursed superficially along the forearm, anterior to the flexor muscles. The superficial radial artery emerged from the brachial artery and ran subcutaneously in the distal forearm. These arteries remained in close relation to key neural and venous structures, increasing their vulnerability to clinical error. Conclusions: The identification of high-origin superficial arteries is essential for clinical practice. Ultrasound serves as a reliable, non-invasive method for detecting such variations preoperatively. Awareness of these anomalies can prevent inadvertent vascular injuries, improve diagnostic accuracy, and inform safer surgical and anesthetic approaches in upper limb interventions. Full article

Background: The brain’s vascular system has recently been shown to provide an important efflux pathway for cerebral waste clearance (CWC). However, little is known about the influence of aging or diabetes on the CWC. The aim of the current study is to investigate the vasculature contribution to CWC under aging and diabetic conditions. Methods: Male Wistar rats under aging and diabetic conditions were evaluated using dynamic intra-cisterna superparamagnetic iron oxide-enhanced susceptibility-weighted imaging (SPIO-SWI). Theoretical analysis of the expected signal intensity using SPIO-SWI was compared with the corresponding dynamic in vivo images. Quantitative susceptibility mapping (QSM) was used to evaluate the iron-based tracer concentration in the venous system. Results: Our data demonstrated that the theoretical analysis predicted the dynamic changes in the signal intensity after SPIO infusion. The distinct hyperintense signals due to the lower concentration of the SPIO over time in cerebrospinal fluid (CSF) and meningeal lymphatic (ML) vessels likely represented the CWC through various efflux pathways, including cerebral vascular and ML vessels. The QSM analysis further revealed reduced CWC from the vasculature in both the aged and diabetic groups compared to the younger group. Conclusions: Our results demonstrated that SPIO-SWI can quantitatively evaluate the CWC efflux contributions from cerebral vascular vessels under aging or diabetic conditions. Full article

Background/Objectives: Intracranial arteriovenous malformations (AVMs) exhibit a complex vasculature characterized by a locally occurring tangled nidus connecting the arterial and venous system bypassing the capillary network. Clinically available imaging modalities may not give sufficient spatial or temporal resolution. Adequate 3D models of large vascular areas and a detailed blood flow analysis of the nidus including the surrounding vessels are not available yet. Methods: Three representative AVM cases containing multimodal image data (3D rotational angiography, magnetic resonance angiography, magnetic resonance venography, and phase-contrast quantitative magnetic resonance imaging) are investigated. Image segmentation results in partial 3D models of the different vascular segments, which are merged into large-scale neurovascular models. Subsequently, image-based blood flow simulations are conducted based on the segmented models using patient-specific flow measurements as boundary conditions. Results: The segmentation results provide comprehensive 3D models of the overall arteriovenous morphology including realistic nidus vessels. The qualitative results of the hemodynamic simulations show realistic flow behavior in the complex vasculature. Feeding arteries exhibit increased wall shear stress (WSS) and higher flow velocities in two cases compared to contralateral vessels. In addition, feeding arteries are exposed to higher overall WSS with increased value variation between individual vessels (20.1 Pa ± 17.3 Pa) compared to the draining veins having a 62% lower WSS (8.9 Pa ± 5.9 Pa). Blood flow distribution is dragged towards the dominating circulation side feeding the nidus for all the cases quantified by the volume flow direction changes in the posterior communicating arteries. Conclusions: This multimodal study demonstrates the feasibility of the presented workflow to acquire detailed blood flow predictions in large-scale AVM models based on complex image data. The hemodynamic models serve as a base for endovascular treatment modeling influencing flow patterns in distally located vasculatures. Full article

Pulmonary hypertension (PH) is a progressive disorder characterized by obstructive changes in the pulmonary vasculature, leading to increased pulmonary vascular resistance (PVR), right ventricular (RV) strain, and eventual RV failure (RVF). Despite advancements in medical therapy, PH remains associated with significant morbidity and mortality, particularly in children. RVF is a clinical syndrome resulting from complex structural and functional remodeling of the right heart, leading to inadequate pulmonary circulation, reduced cardiac output, and elevated venous pressure. Management paradigms for pediatric PH diverge significantly from those in adults, particularly due to the predominance of congenital heart disease (CHD) and the dynamic nature of pediatric cardiovascular and pulmonary development. CHD remains a principal driver of PH in children, and its associated pathophysiology demands a nuanced approach. In patients with unrepaired left-to-right shunts, elevated pulmonary blood flow can lead to progressive pulmonary vascular remodeling and increased PVR. The postoperative persistence or progression of PH may occur if irreversible vascular changes have already developed. Current PH treatments primarily focus on reducing PVR, yet distinguishing between therapeutic approaches that target the pulmonary vasculature and those aimed at improving RV function remain challenging. In pediatric patients with progressive PH despite optimal therapy, additional targeted interventions may be necessary to mitigate RV dysfunction and disease progression. This review provides a comprehensive analysis of the mechanisms underlying RVF in PH, incorporating insights from clinical studies in adults and experimental models, while highlighting the unique considerations in children. Furthermore, it explores current pharmacological and interventional treatment strategies, emphasizing the need for novel therapeutic approaches aimed at directly reversing RV remodeling. Given the complexities of RV adaptation in pediatric PH, further research into disease-modifying treatments and innovative interventions is crucial to improving long-term outcomes in affected children. Full article

Vascular liver diseases (VLDs) include different pathological conditions that affect the liver vasculature at the level of the portal venous system, hepatic artery, or venous outflow system. Although serological investigations and sometimes histology might be required to clarify the underlying diagnosis, imaging has a crucial role in highlighting liver inflow or outflow obstructions and their potential causes. Cross-sectional imaging provides a panoramic view of liver vascular anatomy and parenchymal patterns of enhancement, making it extremely useful for the diagnosis and follow-up of VLDs. Nevertheless, multiparametric ultrasound analysis provides information useful for differentiating acute from chronic portal vein thrombosis, distinguishing neoplastic invasion of the portal vein from bland thrombus, and clarifying the causes of venous outflow obstruction. Color Doppler analysis measures blood flow velocity and direction, which are very important in the assessment of VLDs. Finally, liver and spleen elastography complete the assessment by providing intrahepatic and intrasplenic stiffness measurements, offering further diagnostic information. Full article

During the COVID-19 pandemic, there was increased interest in the issue of thrombotic complications of acute respiratory infections. Clinical reports and pathological studies have revealed that thrombus formation in COVID-19 may involve the venous and arterial vasculature. As thrombotic complications of infectious respiratory diseases are increasingly considered in the context of COVID-19, the fact that thrombosis in lung diseases of viral and bacterial etiology was described long before the pandemic is overlooked. Pre-pandemic studies show that bacterial and viral respiratory infections are associated with an increased risk of thrombotic complications such as myocardial infarction, ischemic stroke, pulmonary embolism, and other critical illnesses caused by arterial and venous thrombosis. This narrative review article aims to summarize the current evidence regarding thrombotic complications and their pathogenesis in acute lower respiratory tract infections. Full article

Endothelin-1 (ET-1) is a potent vasoconstrictor produced by endothelial cells and cleared from circulating blood mainly in the pulmonary vasculature. In a healthy pulmonary circulation, the rate of local production of ET-1 is less than its rate of clearance. In the present study, we aimed to investigate whether the abnormal pulmonary circulatory handling of ET-1 relates to poor clinical outcomes in patients with coronavirus disease 2019 (COVID-19)-induced acute respiratory distress syndrome (ARDS). To this end, central venous and systemic arterial ET-1 plasma levels were simultaneously measured on Days 1 and 3 following ICU admission in mechanically ventilated COVID-19 patients with ARDS (COVID-19 ARDS, N = 18). Central venous and systemic arterial ET-1 plasma levels were also measured in two distinct SARS-CoV-2-negative mechanically ventilated critically ill patient groups, matched for age, sex, and critical illness severity, with ARDS (non-COVID-19 ARDS, N = 14) or without ARDS (non-COVID-19 non-ARDS, N = 20). Upon ICU admission, COVID-19-induced ARDS patients had higher systemic arterial and central venous ET-1 levels compared to the non-COVID-19 ARDS and non-COVID-19 non-ARDS patients (p < 0.05), yet a normal systemic arterial:central venous (A:V) ET-1 ratio [0.63 (0.49–1.02)], suggesting that pulmonary ET-1 clearance is intact in these patients. On the other hand, the non-COVID-19 ARDS patients demonstrated abnormal ET-1 handling [A:V ET-1 ratio 1.06 (0.93–1.20)], while the non-COVID-19 non-ARDS group showed normal ET-1 handling [0.79 (0.52–1.11)]. On Day 3, the A:V ratio in all three groups was <1. When the COVID-19 ARDS patients were divided based on 28-day ICU mortality, while their systemic arterial and central venous levels did not differ, the A:V ET-1 ratio was statistically significantly higher upon ICU admission in the non-survivors [0.95 (0.78–1.34)] compared to the survivors [0.57 (0.48–0.92), p = 0.027]. Our results highlight the potential importance of ET-1 as both a biomarker and a therapeutic target in critically ill COVID-19 patients. The elevated A:V ET-1 ratio in non-survivors suggests that the early disruption of pulmonary ET-1 handling may be a key marker of poor prognosis. Full article

Coronavirus disease of 2019 (COVID-19) is the respiratory viral infection caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite being a primary respiratory illness, it is commonly complicated by systemic involvement of the vasculature leading to arterial and venous thrombosis. In this review, we will focus on the association between COVID-19 and thrombosis. We will highlight the pathophysiology of COVID-19 coagulopathy. The clinical manifestations of COVID-19 vasculopathy will be discussed with a focus on venous and arterial thromboembolic events. COVID-19 vasculopathy and disseminated intravascular coagulation (DIC) are distinguished within, as well as areas of controversy, such as “long COVID”. Finally, the current professional guidelines on prevention and treatment of thrombosis associated with SARS-CoV-2 infection will be discussed. Full article

Background: This pilot study aimed to evaluate the Retinal Function Imager (RFI) for visualizing retinal vasculature and assessment of blood flow characteristics in patients with retinal vasculitis. The RFI is a non-invasive imaging device measuring the blood flow velocity (BFV) in secondary and tertiary retinal vessels using hemoglobin as an intrinsic motion-contrast agent. Methods: To test the feasibility of the RFI for patients with retinal vasculitis, capillary perfusion maps (nCPMs) were generated from 15 eyes of eight patients (five females; mean age: 49 ± 12 years) with a mean uveitis duration of 74 ± 85 months. Five of these patients had birdshot chorioretinopathy, and three had primarily non-occlusive venous retinal vasculitis of unknown origin. To reflect that the BFV may be more reduced in patients with prolonged disease, patients were classified into a short-term (uveitis duration: 8–15 months) and a long-term uveitis group (uveitis duration: 60–264 months). Data were compared with healthy controls (16 eyes of 11 patients; mean age 45 ± 12 years; 8 females). Results: The mean BFV in the controls was 3.79 ± 0.50 mm/s in the retinal arteries and 2.35 ± 0.44 mm/s in the retinal veins, which was significantly higher compared to the retinal vasculitis group. Patients revealed an arterial BFV of 2.75 ± 0.74 mm/s (p < 0.001) and a venous BFV of 1.75 ± 0.51 mm/s (p = 0.016). In the short-term group, a trend towards a decreased venular and arteriolar BFV was seen, while a significant reduction was observed in the long-term group. The patients’ microvasculature anatomy revealed by the nCPMs appeared unevenly distributed and a lower number of blood vessels were seen, along with a lower degree of complexity of their branching patterns, when compared with controls. Conclusions: This study demonstrated a reduction in venular and arteriolar BFVs in patients with retinal vasculitis. BFV alterations were already observed in early disease stages and became more pronounced in progressed disease. Additionally, we showed that retinal microvasculature changes may be observed by nCPMs. Retinal imaging with the RFI may serve as a diagnostic and quantifying tool in retinal vasculitis. Full article