Hemodynamic Assessment of a Large Pulmonary Arteriovenous Malformation in a Neonate: Case Report and Review of Literature.

Herein we report the case of a neonate with a prenatally diagnosed large pulmonary arteriovenous malformation, managed with minimally invasive hemodynamic monitoring in our Neonatal Intensive Care Unit. The combination of Near-Infrared Spectroscopy and Pressure Recording Analytical Method could guide neonatal management of critical cases of vascular anomalies: immediate data are offered to clinicians, from which therapeutic decisions such as timing of surgical resection are made to achieve a positive outcome. We also systemically collected and summarized information on patients' characteristics of previous cases reported in literature to data, and we compared them to our case.

Assessment of Duplex Ultrasound Carried Out by the Vascular Surgeon After Locoregional Anesthesia for Preferred Arteriovenous Fistula Access.

BACKGROUND: Preoperative vascular mapping by duplex ultrasound is required in construction of an arteriovenous fistula for hemodialysis (AVF). Due to venous vasospasm in cool temperatures and variability of the dialysis patient's blood volume, the conditions for performing this examination may be less than ideal. However, local regional anesthesia (LRA) resulting in vasodilation of the limb, can allow the use of veins considered to be of insufficient caliber during preoperative ultrasound mapping. The aim of this study was to assess the functionality of AVF when duplex ultrasound is performed by the surgeon following LRA. These results were compared with those from the preceding year, during which preoperative duplex ultrasound had been performed without LRA by vascular specialists, (Clinical Trial registration number: NCT04978155). MATERIALS AND METHODS: This is a prospective study of all the patients having received AVF after systematic immediate preoperative ultrasound (US) under LRA (US-LRA group) in 2020. The initial surgical programming based on the Silva criteria was reported by a vascular medicine specialist. The change of AVF strategy following US-LRA was reported together with AVF usability and patency and compared to the results of the control group, in which AVF had been performed in 2019 without US-LRA. RESULTS: Ninety patients were included in the US-LRA group and 93 in the control group. Modified surgical planning was observed in 38% of cases (35/90) in the US-LRA group including more distal AVF in 28% of patients (26/90) and alternative target vein in 6.6% (6/90). AVF usability at 6 weeks was 80% (72/90) in the US-LRA group and 51.6% (48/93) in the control group (P < 0.001). Median follow-up was 12 months [IQR:9-15] in the US-LRA group and 13 months [IQR:9-18] in the control group. Primary patency at 6, 12, 18 months was significantly better in the US-LRA group (73.6% vs. 57.4%, 54.4% vs. 40.2%, 31.3% vs. 28.2%, respectively, P < 0.001). Assisted patency and secondary patency were comparable in the two groups. CONCLUSIONS: This study showed the benefit of having the surgeon perform US-LRA before starting the procedure, thereby allowing for more distal AVF, better usability and patency.

Avaliação clínica da maturação da fístula arteriovenosa para hemodiálise: revisão de escopo / Evaluación clínica de la maduración de la fístula arteriovenosa para hemodiálisis: revisión de alcance / Arteriovenous fistula maturation clinical assessment for hemodialysis: a scoping review

Resumo Objetivo: Mapear as evidências de pesquisa disponíveis para avaliação clínica da maturação da fístula arteriovenosa. Métodos: Estudo do tipo Scoping review, com busca realizada entre outubro a novembro de 2019 nas bases de dados JBI, Cochrane, Biblioteca Virtual em Saúde, PubMed, e CINAHL, sendo incluídos estudos com pacientes maiores de 18 anos, com doença renal crônica pré-dialítica ou já em hemodiálise, submetidos à cirurgia da fístula arteriovenosa; texto disponível; e idiomas inglês, espanhol ou português. Foram excluídos estudos relacionados a fase pós-operatória ou relacionados a cuidados com próteses/enxertos arteriovenosos. Resultados: Foram identificadas 1954 publicações elegíveis, dos quais 38 compuseram a amostra final. O estudo compreendeu publicações entre 1998 e 2018, com abrangência internacional do tema (94,7%). O profissional executor da avaliação foi predominantemente o enfermeiro ou equipe de enfermagem (47,4%), e a avaliação teve início no pós-cirúrgico imediato, até meses após a cirurgia. Dentre as técnicas de avaliação clínica, 23 estudos (60,5%) recomendaram o exame físico e 15 (39,5%) a combinação anamnese e exame físico. Conclusão: A presente revisão apresentou o mapeamento de evidências, nas quais a avaliação clínica da fístula arteriovenosa deve incluir anamnese e exame físico, sendo apresentados vários elementos ligados a permeabilidade e respostas vasculares do acesso. Houve a predominância do profissional enfermeiro como avaliador, sendo ressaltada a necessidade do treinamento para execução da avaliação, além de uma avaliação mais abrangente, com aplicação do Processo e Teorias de Enfermagem, e Linguagens Padronizadas, o que pode propiciar um novo campo de investigação e desenvolvimento na área.

Resumen Objetivo: Mapear las evidencias de investigación disponibles para evaluación clínica de la maduración de la fístula arteriovenosa. Métodos: Estudio tipo scoping review, cuya búsqueda fue realizada entre octubre y noviembre de 2019 en las bases de datos JBI, Cochrane, Biblioteca Virtual em Saúde, PubMed y CINAHL. Se incluyeron estudios con pacientes mayores de 18 años, con enfermedad renal crónica predialítica o ya en hemodiálisis, sometidos a cirugía de fístula arteriovenosa y textos disponibles en inglés, español o portugués. Se excluyeron estudios relacionados con la fase posoperatoria o relacionados con cuidados de prótesis/injertos. Resultados: Se identificaron 1.954 publicaciones elegibles, de las cuales 38 formaron parte de la muestra final. El estudio comprendió publicaciones entre 1998 y 2018, con alcance internacional del tema (94,7 %). El profesional que ejecutó la evaluación fue predominantemente el enfermero o el equipo de enfermería (47,4 %) y la evaluación comenzó en el posoperatorio inmediato, hasta meses después de la cirugía. Entre las técnicas de evaluación clínica, 23 estudios (60,5 %) recomendaron el examen físico y 15 (39,5 %) la combinación entre anamnesis y examen físico. Conclusión: La revisión presentó el mapeo de evidencias, en las cuales la evaluación clínica de la fístula arteriovenosa debe incluir anamnesis y examen físico. También se presentaron varios elementos relacionados con la permeabilidad y respuestas vasculares del acceso. Hubo una predominancia del profesional enfermero como evaluador y se destaca la necesidad de entrenamiento para llevar a cabo la evaluación, además de una evaluación más abarcadora, con aplicación del proceso y teorías de enfermería y un lenguaje estandarizado, lo que puede proporcionar un nuevo campo de investigación y desarrollo del área.

Abstract Objective: To map the available research evidence for arteriovenous fistula maturation clinical assessment. Methods: A scoping review, with a search conducted between October and November 2019 at JBI, Cochrane, Virtual Health Library, PubMed, and CINAHL. Studies with patients over 18 years old, with pre-dialysis chronic kidney disease or already under hemodialysis, who underwent arteriovenous fistula surgery were included; available text; and in English, Spanish, and Brazilian Portuguese. Studies related to the postoperative phase or related to care with prostheses/arteriovenous grafts were excluded. Results: One thousand nine hundred and fifty-four eligible studies were identified; 38 made up the final sample. The study comprised studies between 1998 and 2018, with an international scope of the theme (94.7%). The professional who performed the assessment was predominantly the nurse or nursing team (47.4%), and assessment started in the immediate post-surgical period, even months after surgery. Among the clinical assessment techniques, 23 studies (60.5%) recommended physical examination and 15 (39.5%) the combination of medical history and physical examination. Conclusion: This review presented the mapping of evidence, in which arteriovenous fistula clinical assessment must include medical history and physical examination. Several elements related to the permeability and vascular responses of the access were presented. There was a predominance of professional nurses as evaluators. There was need for training to carry out the assessment, in addition to a more comprehensive assessment, with the application of the Nursing Theory and Standardized Languages and Process, which may provide with a new field of research and development in the area.

Long-Term Functional Patency and Cost-Effectiveness of Arteriovenous Fistula Creation under Regional Anesthesia: a Randomized Controlled Trial.

BACKGROUND: Regional anesthesia improves short-term blood flow through arteriovenous fistulas (AVFs). We previously demonstrated that, compared with local anesthesia, regional anesthesia improves primary AVF patency at 3 months. METHODS: To study the effects of regional versus local anesthesia on longer-term AVF patency, we performed an observer-blinded randomized controlled trial at three university hospitals in Glasgow, United Kingdom. We randomly assigned 126 patients undergoing primary radiocephalic or brachiocephalic AVF creation to receive regional anesthesia (brachial plexus block; 0.5% L-bupivacaine and 1.5% lidocaine with epinephrine) or local anesthesia (0.5% L-bupivacaine and 1% lidocaine). This report includes findings on primary, functional, and secondary patency at 12 months; reinterventions; and additional access procedures (primary outcome measures were previously reported). We analyzed data by intention to treat, and also performed cost-effectiveness analyses. RESULTS: At 12 months, we found higher primary patency among patients receiving regional versus local anesthesia (50 of 63 [79%] versus 37 of 63 [59%] patients; odds ratio [OR], 2.7; 95% confidence interval [95% CI], 1.6 to 3.8; P=0.02) as well as higher functional patency (43 of 63 [68%] versus 31 of 63 [49%] patients; OR, 2.1; 95% CI, 1.5 to 2.7; P=0.008). In 12 months, 21 revisional procedures, 53 new AVFs, and 50 temporary dialysis catheters were required. Regional anesthesia resulted in net savings of £195.10 (US$237.36) per patient at 1 year, and an incremental cost-effectiveness ratio of approximately £12,900 (US$15,694.20) per quality-adjusted life years over a 5-year time horizon. Results were robust after extensive sensitivity and scenario analyses. CONCLUSIONS: Compared with local anesthesia, regional anesthesia significantly improved both primary and functional AVF patency at 1 year and is cost-effective. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: Local Anaesthesia versus Regional Block for Arteriovenous Fistulae, NCT01706354.

Incidence and Management of Late Adverse Radiation Effects After Arteriovenous Malformation Radiosurgery.

BACKGROUND: Late adverse radiation effects (ARE) typically occur many years after stereotactic radiosurgery (SRS) of intracranial arteriovenous malformations (AVM). They are characterized by perilesional edema or cyst formation and are distinct from radiation-induced changes (RIC) noted in the first 1 to 2 years after AVM SRS and radiation necrosis. OBJECTIVE: To determine the incidence of late ARE after AVM SRS. METHODS: Retrospective review of 233 AVM patients having SRS from 1990 to 2009. Patients had sporadic AVM, no prior radiation, and a minimum of 5 years of magnetic resonance imaging (MRI) follow-up. The median MRI follow-up after SRS was 9.8 years (range, 5-24.2). RESULTS: Late ARE were observed in 16 patients (6.9%) at a median of 8.7 years after SRS (range, 2.0-16.1). The 5-, 10-, and 15-year incidence of late ARE was 0.4%, 7.7%, and 12.5%, respectively. Eight patients (3.4%) were symptomatic at the time of ARE detection. Three of 8 patients who were initially asymptomatic had documented cyst progression (at 11, 40, and 42 months), for an overall symptomatic rate of 4.7%. Five patients with asymptomatic ARE have been observed for a median of 9.3 years (range, 2.0-14.1) without progression. Patients having early RIC (hazard ratio [HR] = 2.11, P < .001), patients having obliteration (HR = 1.24, P = .02), and patients having SRS before April 1997 (HR = 1.12, P = .02) were more likely to develop late ARE. CONCLUSION: Late ARE are common in AVM patients who develop early RIC after SRS. Resection of the thrombosed AVM and the adjacent damaged tissue is effective at eliminating the mass effect and improving patients' neurological condition.

Two- and three-dimensional transthoracic echocardiography in the assessment of acquired ascending aortic aneurysm to pulmonary artery fistula.

Aorta to pulmonary artery fistula is an uncommon and potentially fatal condition. This case is of a 48-year-old Caucasian male with congestive heart failure and multiple aortic valve replacement surgeries who presented with an acquired ascending aortic aneurysm to pulmonary artery fistula diagnosed using two-dimensional transthoracic echocardiography via nonstandard imaging windows. Three-dimensional transthoracic echocardiography using live/real time three-dimensional color Doppler was used to assess the size of the opening of the fistula, providing additional value. This patient was surgically managed and is doing well 8 months postoperation.

Experimental validation of a pulse wave propagation model for predicting hemodynamics after vascular access surgery.

Hemodialysis patients require a vascular access that is, preferably, surgically created by connecting an artery and vein in the arm, i.e. an arteriovenous fistula (AVF). The site for AVF creation is chosen by the surgeon based on preoperative diagnostics, but AVFs are still compromised by flow-associated complications. Previously, it was shown that a computational 1D-model is able to describe pressure and flow after AVF surgery. However, predicted flows differed from measurements in 4/10 patients. Differences can be attributed to inaccuracies in Doppler measurements and input data, to neglecting physiological mechanisms or to an incomplete physical description of the pulse wave propagation after AVF surgery. The physical description can be checked by validating against an experimental setup consisting of silicone tubes mimicking the aorta and arm vasculature both before and after AVF surgery, which is the aim of the current study. In such an analysis, the output uncertainty resulting from measurement uncertainty in model input should be quantified. The computational model was fed by geometrical and mechanical properties collected from the setup. Pressure and flow waveforms were simulated and compared with experimental waveforms. The precision of the simulations was determined by performing a Monte Carlo study. It was concluded that the computational model was able to simulate mean pressures and flows accurately, whereas simulated waveforms were less attenuated than experimental ones, likely resulting from neglecting viscoelasticity. Furthermore, it was found that in the analysis output uncertainties, resulting from input uncertainties, cannot be neglected and should thus be considered.

Incremental role of three-dimensional over two-dimensional ultrasound in the assessment of traumatic peripheral arteriovenous fistula.

We present a patient with an accidental self-inflicted stab wound to his right thigh in whom three-dimensional (3D) ultrasound was able to find two communications between the right femoral artery and the femoral vein, in contrast to two-dimensional (2D) peripheral ultrasound which could find only one communication between them, thereby showing an incremental value of 3D over 2D ultrasound.

Giant saccular aneurysm of coronary arteriovenous fistula to the main pulmonary artery: intraoperative assessment by using fluorescent imaging.

Coronary arteriovenous fistulas (CAF) and coronary artery aneurysms (CAA) are uncommon, but their detection has recently increased. In this case we succeeded in identifying the residual shunt flow by using an intraoperative fluorescence imaging technique with indocyanine green after surgical treatment. The photodynamic eye imaging system is based on fluorescence of indocyanine green. This is the first report to identify residual shunt flow with such a giant coronary aneurysm by using fluorescence imaging, and the result indicates that this technique is useful for acceptance as one of the examinations to evaluate CAAs. Furthermore, it may be useful for the detection of shunt cases, such as congenital heart disease.

Assessment of wall shear stress changes in arteries and veins of arteriovenous polytetrafluoroethylene grafts using magnetic resonance imaging.

The purpose of the study was to determine simultaneously the temporal changes in luminal vessel area, blood flow, and wall shear stress (WSS) in both the anastomosed artery (AA) and vein (AV) of arteriovenous polytetrafluoroethylene (PTFE) grafts. PTFE grafts were placed from the iliac artery to the ipsilateral iliac vein in 12 castrated juvenile male pigs. Contrast-enhanced magnetic resonance angiography with cine phase-contrast magnetic resonance imaging was performed. Luminal vessel area, blood flow, and WSS in the aorta, AA, AV, and inferior vena cava were determined at 3 days (D3), 7 days (D7), and 14 days (D14) after graft placement. Elastin von Gieson staining of the AV was performed. The average WSS of the AA was highest at D3 and then decreased by D7 and D14. In contrast, the average WSS and intima-to-media ratio of the AV increased from D3 to D7 and peaked by D14. Similarly, the average area of the AA was highest by D7 and began to approximate the control artery by D14. The average area of the AV had decreased to its lowest by D7. High blood flows through the AA causes a decrease in average WSS and increase in the average luminal vessel area, whereas at the AV, the average WSS and intima-to-media ratio both increase while the average luminal vessel area decreases.

Utility of ultrasonographic venous assessment prior to forearm arteriovenous fistula creation.

AIM: The purpose of this study was to evaluate the clinical utility of Doppler ultrasound (US) prior to native forearm arteriovenous fistula (AVF) creation. MATERIALS AND METHODS: US mapping was carried out pre-operatively to evaluate the major veins and arteries in the appropriate arm. One hundred and 6 patients were identified retrospectively over 2 years with complete clinical and US data. A failed fistula was defined as an inability to provide blood flow to meet adequacy targets by 6 months (urea reduction ratio > or = 65%). RESULTS: Twenty-nine patients (27.4%) had successful forearm AVFs. The mean minimum forearm cephalic vein diameter (CVD) was 2.51 +/- 0.14 and 2.23 +/- 0.06 mm in successful and failed fistulae, respectively (p = 0.04). This result was primarily due to differences observed in women. A receiver operator curve analysis showed that a cutpoint of 2.6 mm for minimum forearm CVD had the greatest predictive value with a likelihood ratio of 3.94 (95% CI: 1.97 - 7.84) for fistula failure. Multivariate logistic regression analysis determined that male gender and minimum forearm CVD were the only significant predictors for fistula success with odds ratios of 3.90 (95% CI: 1.30 - 11.68) and 2.31 (95% CI: 1.00 - 5.43), respectively. The study is limited by the possibility that US results in patients may have lead to an alternative type of access being attempted. CONCLUSIONS: US mapping prior to forearm AVF creation is of modest benefit. Only male gender and minimum forearm CVD were predictive of AVF success.

Surgical and endovascular treatment of spinal dural arteriovenous fistulas: long-term disability assessment and prognostic factors.

OBJECT: The authors assessed clinical outcomes of patients with treated spinal dural arteriovenous fistulas (DAVFs) and investigated prognostic factors. METHODS: Thirty consecutive patients with spinal DAVFs were treated at the authors' institution during the past 15 years: seven underwent surgery; seven underwent surgery after failed embolization: and 16 underwent embolization alone. The outcomes of gait and micturition disability, were analyzed. Follow up averaged 3.4 years (range 1 month-11.8 years). Age, duration of symptoms, pre- and postintervention magnetic resonance (MR) imaging findings, and preintervention disability were correlated with outcome. Seventeen patients (57%) experienced improved gait, 12 (40%) were unchanged, and one (3%) was worse. In 11 patients (37%) micturition function was improved, in 15 (50%) it was unchanged, and in four (13%) it was worse. Gait disability, as measured by the Aminoff-Logue Scale, was significantly improved after treatment, from 3.4+/-1.4 (average +/- standard deviation) to 2.7+/-1.5 (p = 0.007). Mean micturition disability scores decreased, but not significantly, from 1.9+/-1 to 1.6+/-1.1 (p = 0.20). Preintervention gait disability was not associated with improvement except for patients with Aminoff-Logue Scale Grade 4 disability (eight of nine improved; p = 0.024). For patients treated within 13 months of symptom onset, mean micturition disability decreased (p = 0.035). No association was found between clinical improvement and age, a symptom duration less than 30 months, or pre- and postintervention MR imaging-documented spinal cord edema. CONCLUSIONS: Spinal DAVF treatment significantly improved patients' mean gait disability score by almost one grade at last follow up. The mean micturition disability score was not significantly improved, unless treatment was performed within 13 months of symptom onset. Longer and more uniform follow-up study is needed to determine if improved and stabilized clinical outcomes are sustained.

Improve scheduling of fistula patients to slash unnecessary costs, improve care for ESRD.

A $20 cab ride makes the difference. When ESRD patients needed emergency surgery, Senatra Norfolk General Hospital found scheduling to be a huge problem. A little investigation and a $20 cab ride are two of the several tactics administrators used to cut costs dramatically among this population.

Comparison of cost affecting parameters and costs of the "closed" and "open" in situ bypass technique.

OBJECTIVES: The "closed" in situ bypass results in a reduction of wound complications compared to the "open" technique. This advantage is partly diminished by extra costs for the "closed" procedure and a larger percentage of residual arteriovenous (AV)-fistulae. This aim of this study was to analyse costs related to "closed" and "open" procedures. METHODS: The cost affecting parameters: (1) duration of operation; (2) length of hospital stay; and (3) number of treated residual AV-fistulae, were analysed in a randomised group of 73 patients (35 "closed" and 38 "open") in two centres. In addition, costs of the operation, nursing care and treatment of AV-fistulae were analysed. RESULTS: The "closed" and "open" group showed a median duration of operation of 210 min (range 105-570) and 154 min (range 90-355) (p < 0.05), length of hospital stay of 16 days (range 5-51) and 25 days (range 12-65) (p < 0.01), and a percentage of patients treated for residual AV-fistulae of 40% and 5%, respectively (p < 0.01). The median "closed" operation was US$798 more expensive than the "open". Median postoperative care was US$2664 less for the "closed" group. Mean estimated costs for treatment of AV-fistulae was US$9 in the "open" and US$167 in the "closed" group. CONCLUSION: The "closed" in situ vein bypass technique is cost-effective in comparison with the "open" technique.

The preoperative assessment of stroke risk in lesions involving the internal carotid artery.

Patients with vascular or tumourous lesions involving the internal carotid artery are at risk of damage or occlusion of this vessel during surgical or endovascular procedures. To assess the stroke risk transcranial Doppler aided carotid compression tests were performed in 82 patients. Based on changes of blood flow velocity (BFV), pulsatility index, systolic/diastolic ratio and length of transient hyperaemic response three groups could be differentiated. Patients in group A (31%) showed only a slight reaction of BFV and were at minimal risk in case of carotid occlusion. Patients in group B (52%) underwent a distinct decrease of Doppler readings with partial improvement and were considered to have moderate to high stroke risk. In group C patients (17%) trial occlusion caused a dramatic reduction of BFV with no recovery (p < 0.01), which denotes a very high stroke risk. Transcranial Doppler aided carotid occlusion manoeuvres provide useful information on cerebrovascular collateral capacity and prognosis of stroke risk.