Early experience of thalidomide therapy for high-grade peripheral and facial arteriovenous malformations.

BACKGROUND: Arteriovenous malformations (AVMs) are developmental defects in the vascular system with abnormal connections between arteries and veins. A minority of AVMs are characterized by aggressive growth and continue to proliferate despite maximal surgical and interventional therapy. We report our outcomes with the use of thalidomide as the only UK specialist center adopting this novel approach for the management of AVMs refractory to conventional therapy. METHODS: This was a retrospective case series which included only complex and proliferative AVM lesions (Schobinger grade III and IV). All patients prescribed thalidomide on a compassionate basis between September 2006 and August 2022 after attempts at embolosclerotherapy without satisfactory response were reviewed. RESULTS: Eleven patients were included in our study. The median total duration of thalidomide use was 10 months. Two thirds of patients with pain (six of nine) reported an improvement, three quarters reported a reduction in swelling (six of eight) and all who presented with bleeding reported improvement in overall volume or frequency (four of four). Over the study period, 45% achieved a non-proliferative state with no further target vessel demonstrable on angiography. Mild, tolerable side effects such as fatigue were common (73%). There was only one major adverse reaction (neutropenia) necessitating cessation of therapy. CONCLUSIONS: We can conclude that thalidomide is able to reduce the symptom burden for patients with complex and proliferative AVMs that were refractory to established treatment modalities. Adverse effects are common, but the benefit achieved from taking thalidomide in otherwise treatment resistant cases outweighs the risks, most of which are manageable.

Efficacy and safety of foam sclerotherapy with sodium tetradecyl sulfate as preferred sclerosant of venous malformations based on experience from a single specialist center.

OBJECTIVE: We have assessed the efficacy and safety of interventional therapy for venous malformations (VMs), with foam sclerotherapy as the treatment of choice according to our experience at a single specialist center. METHODS: All the patients with VMs who had undergone interventional therapy (ie, embolo-sclerotherapy and/or open surgery) from January 1, 2015 to December 31, 2019 were identified through a prospective database. The VM types were classified according to the Puig classification. The outcome measures assessed included the efficacy and complications. The former was divided into four groups: no response, mild response, moderate response, and complete response. The complications were defined as any tissue or functional damage, distal embolization, or tissue reaction. The continuous variables were compared using the analysis of variance F test, and discrete variables were analyzed using the χ2 tests. P values < .05 were considered statistically significant. RESULTS: A total of 207 patients were included. Puig type I lesions were significantly less likely to have received foam sclerotherapy using sodium tetradecyl sulfate (STS) 3% (P ≤ .001) and more likely to have been surgically excised (P ≤ .001). At the patient's first procedure during the study period, the volumes of foam STS 3% were significantly different across all types of VM (P ≤ .001). The patients with type I VMs had received a lower volume of STS 3% compared with those with type II and III VMs. The efficacy outcome categories were significantly different across all types of VMs (P ≤ .001). Overall, only 14 patients (6.8%) had reported no improvement in efficacy, and 38 patients (18%) had not attended follow-up. Therefore, 154 patients (74.8%) had experienced some form of efficacious outcome. Ten patients (4.8%) had developed complications such as hematoma, thrombophlebitis, and ulceration. The incidence of complications differed significantly across the categories (P = .030), with more complications reported for those with type I VMs. CONCLUSIONS: We found that intervention with foam sclerotherapy using STS 3% is clinically effective and safe for patients with VMs and was most successful for those with Puig type I and II VMs.

Lower Limb Weakness due to Spinal Venous Congestion in Chronic Inferior Vena Cava Occlusion: A Case Report.

CASE REPORT: A 31 year-old male presented with a long history of reduced sensation and motor function in his lower limbs upon waking every morning, lasting 30-50 minutes during which he was unable to ambulate. He was involved in a severe road traffic accident as a child, and was born prematurely requiring prolonged neonatal hospitalisation. Both duplex ultrasonography and magnetic resonance venography identified an occlusion of the IVC, with patent common femoral and iliac veins draining into large spinal collaterals. No other cause was identified for his symptoms. After appropriate multidisciplinary team discussion and patient counselling, the patient proceeded to have endovenous recanalization of his IVC and common iliac veins with dedicated venous stents. Post-operatively, the patient reported an immediate resolution of neurological symptoms, with an improvement in quality of life questionnaire scores and with stent patency at 9-month follow up. CONCLUSION: IVC occlusion with symptomatic spinal venous congestion is a rare condition which may be successfully treated with endovascular iliocaval recanalization, although long-term outcomes of this treatment are still unknown.

Presentation, treatment, and outcome of renovascular hypertension below 2 years of age.

Renovascular hypertension in most cases requires endovascular treatment and/or surgery. This is technically much more difficult in small children and there is very limited published knowledge in this age group. We here present treatment and outcome of young children with renovascular hypertension at our institution. Children below 2 years of age, with renovascular hypertension between January 1998 and March 2020 were retrospectively reviewed. Demographics and treatment modalities were noted. Primary outcome was blood pressure within a week after the procedures and at last available visit. Sixty-six angiographies were performed in 34 patients. Median age at time of first angiography was 1.03 (interquartile range (IQR) 0.4-1.4) years and systolic blood pressure at presentation 130 (IQR 130-150) mm Hg. Thirty-eight percent (13/34) of children were incidentally diagnosed and 18% (6/34) presented with heart failure. Twenty-six (76%) children had main renal artery stenosis and 17 (50%) mid-aortic syndrome. Seventeen (50%) children showed intrarenal, six (18%) mesenteric, and three (9%) cerebrovascular involvement. Twenty patients underwent 45 percutaneous transluminal angioplasty procedures and seven children surgeries. In 44% of the 16 patients who underwent only percutaneous transluminal angioplasty blood pressure was normalized, 38% had improvement on same or decreased treatment and 19% showed no improvement. Complications were seen in 7.5% (5/66) of angiographies. In four of the seven (57%) children who underwent surgery blood pressure was normalized, two had improved (29%) and one unchanged (14%) blood pressure. CONCLUSION: In small children with renovascular hypertension below the age of 2 years, percutaneous transluminal angioplasty caused significant improvement in blood pressure with low complication profile. Surgery can be recommended where percutaneous transluminal angioplasty and medical treatments failed. WHAT IS KNOWN: • Renovascular hypertension is diagnosed in all age groups from a few weeks of life until adulthood. • Both angioplasty and surgery are significantly more difficult to perform in small children and the published information on short and long-term outcome in these children is very scarce. WHAT IS NEW: • Children below the age of two years can safely and successfully undergo selective renal angiography and also safely be treated with angioplasty. • We here present a large group of babies and infants where angioplasty and in some cases surgery effectively and safely improved their blood pressure.

A patient-specific multi-modality abdominal aortic aneurysm imaging phantom.

PURPOSE: Multimodality imaging of the vascular system is a rapidly growing area of innovation and research, which is increasing with awareness of the dangers of ionizing radiation. Phantom models that are applicable across multiple imaging modalities facilitate testing and comparisons in pre-clinical studies of new devices. Additionally, phantom models are of benefit to surgical trainees for gaining experience with new techniques. We propose a temperature-stable, high-fidelity method for creating complex abdominal aortic aneurysm phantoms that are compatible with both radiation-based, and ultrasound-based imaging modalities, using low cost materials. METHODS: Volumetric CT data of an abdominal aortic aneurysm were acquired. Regions of interest were segmented to form a model compatible with 3D printing. The novel phantom fabrication method comprised a hybrid approach of using 3D printing of water-soluble materials to create wall-less, patient-derived vascular structures embedded within tailored tissue-mimicking materials to create realistic surrounding tissues. A non-soluble 3-D printed spine was included to provide a radiological landmark. RESULTS: The phantom was found to provide realistic appearances with intravascular ultrasound, computed tomography and transcutaneous ultrasound. Furthermore, the utility of this phantom as a training model was demonstrated during a simulated endovascular aneurysm repair procedure with image fusion. CONCLUSION: With the hybrid fabrication method demonstrated here, complex multimodality imaging patient-derived vascular phantoms can be successfully fabricated. These have potential roles in the benchtop development of emerging imaging technologies, refinement of novel minimally invasive surgical techniques and as clinical training tools.

Platelet Biomarkers in Patients with Atherosclerotic Extracranial Carotid Artery Stenosis: A Systematic Review.

OBJECTIVE: The aim was to enhance understanding of the role of platelet biomarkers in the pathogenesis of vascular events and risk stratifying patients with asymptomatic or symptomatic atherosclerotic carotid stenosis. DATA SOURCES: Systematic review conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. REVIEW METHODS: A systematic review collated data from 1975 to 2020 on ex vivo platelet activation and platelet function/reactivity in patients with atherosclerotic carotid stenosis. RESULTS: Forty-three studies met the inclusion criteria; the majority included patients on antiplatelet therapy. Five studies showed increased platelet biomarkers in patients with ≥ 30% asymptomatic carotid stenosis (ACS) vs. controls, with one neutral study. Preliminary data from one study suggested that quantification of "coated platelets" in combination with stenosis severity may aid risk stratification in patients with ≥ 50% - 99% ACS. Platelets were excessively activated in patients with ≥ 30% symptomatic carotid stenosis (SCS) vs. controls (≥ 11 positive studies and one neutral study). Antiplatelet-High on Treatment Platelet Reactivity (HTPR), previously called "antiplatelet resistance", was observed in 23% - 57% of patients on aspirin, with clopidogrel-HTPR in 25% - 100% of patients with ≥ 50% - 99% ACS. Aspirin-HTPR was noted in 9.5% - 64% and clopidogrel-HTPR in 0 - 83% of patients with ≥ 50% SCS. However, the data do not currently support the use of ex vivo platelet function/reactivity testing to tailor antiplatelet therapy outside of a research setting. Platelets are excessively activated (n = 5), with increased platelet counts (n = 3) in recently symptomatic vs. asymptomatic patients, including those without micro-emboli on transcranial Doppler (TCD) monitoring (n = 2). Most available studies (n = 7) showed that platelets become more reactive or activated following carotid endarterectomy or stenting, either as an acute phase response to intervention or peri-procedural treatment. CONCLUSION: Platelets are excessively activated in patients with carotid stenosis vs. controls, in recently symptomatic vs. asymptomatic patients, and may become activated/hyper-reactive following carotid interventions despite commonly prescribed antiplatelet regimens. Further prospective multicentre studies are required to determine whether models combining clinical, neurovascular imaging, and platelet biomarker data can facilitate optimised antiplatelet therapy in individual patients with carotid stenosis.

Quality of life and mental health of patients with vascular malformations in a single specialist center in the United Kingdom.

OBJECTIVE: Patients with vascular malformations suffer from chronic debilitating symptoms that have been shown to contribute negatively to their quality of life (QoL) and mental health. Despite this, the current literature evaluating the QoL and mental health of patients with vascular malformations remains scarce. Our aim was to evaluate the QoL and mental health of patients with vascular malformations. METHODS: We prospectively analyzed the validated health-related QoL (HRQoL) questionnaires: the RAND Health Care 36-Item Short Form Survey (SF-36), Hospital Anxiety and Depression Scale (HADS), and visual analogue score for pain reported by 253 patients with vascular malformations in a specialist center of vascular anomalies in the UK over 2 years. RESULTS: Patients with vascular malformations reported significantly poorer SF-36 scores in all domains compared with the UK general population. Patients with low-flow vascular malformations and arteriovenous malformations reported little variations in SF-36, HADS, and visual analogue score for pain scores. No significant association was found between age and any of the health-related QoL scores, other than the physical functioning in SF-36. Female patients reported significantly lower physical and social functioning of SF-36 and worse HADS-Depression than their male counterparts. Patients with syndromic vascular malformations reported significantly lower SF-36 scores in role-physical, role-emotional and bodily pain than nonsyndromic vascular malformations. CONCLUSIONS: This study concluded that patients with vascular malformations reported worse QoL than the UK general population. Therefore, the assessment and management of QoL and mental health should be incorporated into the overall treatment strategies of patients with vascular malformations.

Single Center Experience of Sirolimus Therapy in Head and Neck Low-flow Vascular Malformations.

OBJECTIVE: Recently, studies have shown that sirolimus is clinically efficacious in the treatment of some low-flow vascular malformations (LFVM). This study aimed to assess the efficacy and safety of sirolimus in treating complex head and neck (H&N) LFVM that were challenging and/or refractory to standard treatment. METHODS: Each patient had baseline and 6-months assessments consisting of clinical history and examination, quality of life (QoL) questionnaires, laboratory investigations, MRI and medical photography. Patients were followed up 1-week and then 1-monthly for 6-months. Wilcoxon signed-rank test was used to compare pre-and 6-months treatment in all 8 domains of RAND 36-Item Short Form Health Survey (SF-36), hospital anxiety and depression scale (HADS), and visual analog score for pain (VAS-P). P < 0.05 was considered significant. RESULTS: Seven patients (median age 43 years, range 23-65 years) were recruited. Six patients completed the six-months course of therapy with 1 patient withdrawing due to intolerable side effects. All six patients reported reduction of swelling with and without other symptom improvement related to the vascular malformations while on treatment. However, at 1-month review after discontinuation of sirolimus, 5 patients reported return of initial symptoms. Overall, patients demonstrated an improvement in QoL six-months treatment but there was no statistical significance (P > 0.05) in all 8 domains of SF-36, HADS and VAS-P. Five patients demonstrated a minimum 10% decrease in lesion size six-months treatment (median 21%, range 13-40%). A Wilcoxon signed-rank test showed that sirolimus treatment did elicit a statistically significant change in lesion size in either direction (Z = -1.992, P = 0.046). The most common side effects found were dyslipidaemia (n-4) and mouth ulcers (n = 2). CONCLUSION: In our preliminary experience, sirolimus is effective and safe in treating patients with complex H&N LFVM. This provides an alternative treatment where standard treatment is challenging and/or refractory.

Patient radiation exposure from embolo-sclerotherapy of peripheral vascular malformations.

OBJECTIVE: Embolo-sclerotherapy (EST) is the mainstay therapy for peripheral vascular malformations that involves the exposure of patients to ionizing radiation. We analyzed the radiation exposure to patients from EST of peripheral vascular malformations during a 5-year period in a single specialist center. METHODS: All patients who had undergone EST at a single specialist center for peripheral vascular malformations from January 1, 2013 to January 8, 2018 were identified from a prospectively collected database. Data collection included basic demographics, procedure date, anatomic site, type of vascular malformations, and procedural details. Radiation exposure, measured as the dose-area product (DAP) and fluoroscopy time, of all patients who had undergone EST during the study period were retrospectively reviewed. Statistical analysis was performed using the Mann-Whitney U and Kruskal-Wallis tests for comparison between subgroups. P < .05 was considered statistically significant. RESULTS: A total of 237 patients (median age, 30 years; range, 1-73 years) had undergone 419 EST sessions during the study period. Of the 237 patients, 61 (25.7%) had had arteriovenous malformations (AVMs) and had undergone 140 EST sessions (33.4%) and 176 (74.3%) had had venous and lymphatic malformations and had undergone 279 EST sessions (66.6%). Patients with AVMs had undergone a median of 2 procedures (range, 1-13) compared with a median of 1 (range, 1-6) for venous and lymphatic malformations within the study period. The median DAP for the single and cumulative EST for peripheral vascular malformations was 1.26 Gycm2 (range, 0.00-698.36 Gycm2) and 1.91 Gycm2 (range, 0.00-1300.24 Gycm2), respectively. The median fluoroscopy time for single and cumulative EST was 19 seconds (range, 1-3846 seconds) and 30 seconds (range, 1-5843 seconds), respectively. Significantly greater patient radiation exposure, in DAP and fluoroscopy time, was measured for single and cumulative EST for AVMs compared with venous and lymphatic malformations (P < .01 for both; Mann-Whitney U test). A significant difference in DAP but not fluoroscopy time was found when the anatomic areas of vascular malformations were compared. CONCLUSIONS: Patient radiation exposure for EST for peripheral vascular malformations, measured in DAP and fluoroscopy time, appeared to be generally less than that reported for endovascular arterial and deep venous interventions. However, some patients with peripheral vascular malformations received relatively high radiation doses. Further studies to investigate the risk factors and long-term side effects of radiation exposure in these patients and strategies to reduce these are required.

Obesity as a Risk Factor for Radiographic Contrast-Induced Nephropathy.

Contrast-induced nephropathy (CIN) is common. Risk factors include preexisting renal impairment, diabetes, elderly age, and dehydration. In a single-centre prospective study, we investigated which factors are implicated for CIN in patients with peripheral arterial disease due for angiography. Serum creatinine was measured before, 1, 2, and 7 days post-angiography. We also considered the chronic kidney disease stage of the patients at admission and 48 hours post-contrast. All patients received 500 mL normal saline pre- and post-angiography and a low-osmolality contrast medium. 6 of 94 patients developed CIN: 1 required dialysis and 1 died partly due to renal failure. Only 2 factors were associated with CIN: body mass index (BMI; P = .019) and kidney function (P = .001); 4 of 6 patients with CIN were obese (BMI ≥30) and only 2 were nonobese (P = .0092). Diabetes, contrast volume, and age were not significant risk factors. Our results confirm renal impairment raises the risk of CIN. To our knowledge, we report for the first time that obesity may be a risk factor for CIN. Pending confirmatory studies and given the rising prevalence of obesity, this finding could help identify at-risk patients and hence reduce the burden of CIN.

Emerging importance of molecular pathogenesis of vascular malformations in clinical practice and classifications.

Vascular malformations occur during early vascular development resulting in abnormally formed vessels that can manifest as arterial, venous, capillary or lymphatic lesions, or in combination, and include local tissue overdevelopment. Vascular malformations are largely caused by sporadic somatic gene mutations. This article aims to review and discuss current molecular signaling pathways and therapeutic targets for vascular malformations and to classify vascular malformations according to the molecular pathways involved. A literature review was performed using Embase and Medline. Different MeSH terms were combined for the search strategy, with the aim of encompassing all studies describing the classification, pathogenesis, and treatment of vascular malformations. Major pathways involved in the pathogenesis of vascular malformations are vascular endothelial growth factor (VEGF), Ras/Raf/MEK/ERK, angiopoietin-TIE2, transforming growth factor beta (TGF-ß), and PI3K/AKT/mTOR. These pathways are involved in controlling cellular growth, apoptosis, differentiation, and proliferation, and play a central role in endothelial cell signaling and angiogenesis. Many vascular malformations share similar aberrant molecular signaling pathways with cancers and inflammatory disorders. Therefore, selective anticancer agents and immunosuppressants may be beneficial in treating vascular malformations of specific mutations. The current classification systems of vascular malformations, including the International Society of the Study of Vascular Anomalies (ISSVA) classification, are primarily observational and clinical, and are not based on the molecular pathways involved in the pathogenesis of the condition. Several molecular pathways with potential therapeutic targets have been demonstrated to contribute to the development of various vascular anomalies. Classifying vascular malformations based on their molecular pathogenesis may improve treatment by determining the underlying nature of the condition and their potential therapeutic target.

Specific Conformational Dynamics and Expansion Underpin a Multi-Step Mechanism for Specific Binding of p27 with Cdk2/Cyclin A.

The protein p27, a prominent regulatory protein in eukaryotes and an intrinsically disordered protein (IDP), regulates cell division by causing cell cycle arrest when bound in ternary complex with cyclin-dependent kinase (Cdk2) and cyclins (e.g., Cdk2/Cyclin A). We present an integrative study of p27 and its binding to Cdk2/Cyclin A complex by performing single-molecule multiparameter fluorescence spectroscopy, stopped-flow experiments, and molecular dynamics simulations. Our results suggest that unbound p27 adopts a compact conformation and undergoes conformational dynamics across several orders of magnitude in time (nano-to milliseconds), reflecting a multi-step mechanism for binding Cdk2/Cyclin A. Mutagenesis studies reveal that the region D1 in p27 plays a significant role in mediating the association kinetics, undergoing conformational rearrangement upon initial binding. Additionally, FRET experiments indicate an expansion of p27 throughout binding. The detected local and long-range structural dynamics suggest that p27 exhibits a limited binding surface in the unbound form, and stochastic conformational changes in D1 facilitate initial binding to Cdk2/Cyclin A complex. Furthermore, the post-kinase inhibitory domain (post-KID) region of p27 exchanges between distinct conformational ensembles: an extended regime exhibiting worm-like chain behavior, and a compact ensemble, which may protect p27 against nonspecific interactions. In summary, the binding interaction involves three steps: (i) D1 initiates binding, (ii) p27 wraps around Cdk2/Cyclin A and D2 binds, and (iii) the fully-formed fuzzy ternary complex is formed concomitantly with an extension of the post-KID region. An understanding of how the IDP nature of p27 underpins its functional interactions with Cdk2/Cyclin A provides insight into the complex binding mechanisms of IDPs and their regulatory mechanisms.

Development of a structured virtual reality curriculum for laparoscopic appendicectomy.

BACKGROUND: Laparoscopic appendicectomy (LA) is a common surgical emergency procedure mainly performed by trainees. The aim was to develop a step-wise structured virtual reality (VR) curriculum for LA to allow junior surgeons to hone their skills in a safe and controlled environment. METHODS: A prospective randomized study was designed using a high-fidelity VR simulator. Thirty-five novices and 25 experts participated in the assessment and their performances were compared to assess construct validity. Learning curve analysis was performed. RESULTS: Five of the psychomotor tasks and all appendicectomy tasks showed construct validity. Learning was demonstrated in the majority of construct-valid tasks. A novel goal-directed VR curriculum for LA was constructed. CONCLUSIONS: A step-wise structured VR curriculum for LA is proposed with a framework which includes computer generated metrics and supports deliberate practice, spacing intervals, human instruction/feedback and assessment. Future study should test the feasibility of its implementation and transferability of acquired skill.

Successful Repair of a Vasculopathic Aneurysmal Brachial Artery in a Patient with Type 1 Neurofibromatosis.

Vasculopathy is a well-recognized abnormality associated with neurofibromatosis type 1(NF1) and may cause stenoses, aneurysms, and arteriovenous malformations. We report a challenging case of a woman with NF1, who presented with spontaneous rupture of a brachial aneurysm around her right elbow, on a background of previous debulking and soft tissue reconstructive surgery in the same arm. She underwent successful delayed reconstruction of the brachial artery using an autologous great saphenous vein graft.

Optimal Antiplatelet Therapy in Moderate to Severe Asymptomatic and Symptomatic Carotid Stenosis: A Comprehensive Review of the Literature.

OBJECTIVES: Carotid stenosis patients are at risk of vascular events despite antiplatelet therapy. Data on prescribed antiplatelet regimens have not been comprehensively collated from trials to guide optimal therapy in this population. METHODS: This review was conducted in line with the current Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Medline, Ovid, Embase, Web of Science, and Google Scholar from 1988 to 2018 were searched using the search terms "carotid stenosis", "asymptomatic", "symptomatic", "antiplatelet", and "anti-platelet" to identify randomised trials in patients with asymptomatic or symptomatic extracranial moderate-severe carotid stenosis on any form of antiplatelet therapy in which vascular events and pre specified composite outcome events were reported. RESULTS: Twenty-five studies were judged eligible for inclusion. Data from one randomised controlled trial showed no significant difference in benefit with aspirin versus placebo in asymptomatic carotid stenosis, but it is still reasonable to recommend aspirin (81-325 mg daily) for prevention of vascular events in these patients. Low to medium dose aspirin (81-325 mg daily) is superior to higher doses (>650 mg daily) at preventing recurrent vascular events in patients undergoing endarterectomy. Data from endovascular treatment (EVT) trials support peri-procedural treatment of asymptomatic and symptomatic patients with 81-325 mg of aspirin daily. The use of peri-procedural aspirin-clopidogrel in patients undergoing EVT is based on one pilot trial, but appears safe. Short-term aspirin-dipyridamole or aspirin-clopidogrel treatments are equally effective at reducing micro-embolic signals on transcranial Doppler ultrasound in patients with ≥50% symptomatic carotid stenosis. There is insufficient evidence to recommend routine aspirin-clopidogrel combination therapy to reduce the risk of recurrent clinical ischaemic events in patients with symptomatic moderate-severe carotid stenosis. CONCLUSIONS: This comprehensive review outlines an evidence based approach to antiplatelet therapy in carotid stenosis patients. Future trials should randomise such patients to receive different antiplatelet regimens to assess their efficacy and safety and to optimise peri-procedural and long-term preventive treatment in this patient cohort.

Evaluation of experimental methods for nitric oxide release from cardiovascular implants; bypass grafts as an exemplar.

BACKGROUND: There is a great potential for nitric oxide (NO) eluting biomaterials in biomedical applications. These include the development of cardiovascular implants, wound healing products, or applications in cancer and respiratory therapy. While the potential of these materials as a therapy is becoming clearer, the real-time monitoring of NO is not easy and the success in the development of such materials depends on the accurate quantification of NO release. METHOD: To emphasize on the importance of a measurement technique on the outcome of an experiment, we compared total NO released from S-nitroso-N-acetyl-d-penicillamine (SNAP) incorporated nanocomposite polymer in the form of bypass grafts under simulated physiological conditions using amperometric and chemiluminescence techniques. RESULTS: We found that the total amount of NO measured by the amperometric technique was 35.8% of the theoretical amount. Similarly, on measuring NO release from the bypass grafts, we demonstrated that the chemiluminesence technique detected NO at a relatively higher level. CONCLUSIONS: The results of this study clearly demonstrate the relative difference between analysis techniques for accurate NO detection that can be applied to distinct experimental models associated with NO-eluting cardiovascular implants.

The performance of a small-calibre graft for vascular reconstructions in a senescent sheep model.

There is an acute clinical need for small-calibre (<6 mm) vascular grafts for surgery. The aim of this study was to evaluate the long-term performance of a small-calibre graft produced from a nanocomposite biomaterial, polyhedral oligomeric silsesquioxane poly(carbonate-urea)urethane (POSS-PCU), in a large animal model following Good Manufacturing Practice (GMP) and Good Laboratory Practice (GLP) protocols. Grafts were characterised and implanted into the left carotid artery (LCA) of senescent sheep (n = 11) for a period of 9 months. In vivo compliance and blood flow rates were measured using ultrasound wall tracking software and a Transonic flow meter. Graft patency and degree of intimal hyperplasia (IH) were examined at the study end point. Seven of the POSS-PCU grafts were free from thrombosis, IH, calcification and aneurysmal dilation, with 4 occluding within 14 days. All of the ePTFE controls (n = 4) were found to be occluded by day 32. The lumen of the patent POSS-PCU grafts was free from any cellular deposits, whilst perigraft tissue could be seen to be infiltrating into the body of the graft from the adventitia. No significant differences were detected between the blood flow rates (p = 0.3693) and compliance (p = 0.9706) of the POSS-PCU grafts and the native artery, either post-operatively or after 9 months implantation. Small-calibre vascular grafts produced from POSS-PCU offer a viable option for the clinical use in revascularisation procedures with a patency rate of 64%.

Best evidence for medical therapy for carotid artery stenosis.

Carotid atheromatous disease is an important cause of stroke and represents a key target in stroke prevention. Randomized trials have shown the efficacy of carotid endarterectomy in secondary stroke prevention. Carotid stenting presents a less invasive alternative to surgical intervention. Advances in medical management, if compliance can be ensured, are leading to improvement in outcomes when implemented as sole therapy in the treatment of atherosclerotic carotid stenosis. This includes lifestyle modification, blood pressure control, and antiplatelet and statin therapy. Over the last 20 years, the annual rate of ipsilateral stroke associated with asymptomatic carotid stenosis has decreased from 2% to 4% to less than 1%. This is largely due to improvements in medical therapy. However, despite numerous trials and years of clinical research, the optimal management of symptomatic and asymptomatic carotid disease remains controversial. This article presents and summarizes the evidence supporting best medical treatment for carotid artery stenosis.