Practical guide of vascular ultrasound in arteriovenous fistulae.

The use of vascular ultrasound, especially with the increasing prevalence of percutaneous arteriovenous fistulas, has taken a central role as a diagnostic and therapeutic imaging procedure in vascular access creation. The current review article stresses the importance of vascular ultrasound in arteriovenous fistula, from planning to creation to maintenance. It summarises and gives practical guidance regarding sonographic criteria for vascular access procedure planning, the application of vascular ultrasound intraoperatively and during follow-up. Ultrasound education and training modalities to meet high standards of patient care in hemodialysis are presented.

Ultrasound-guided venous pressure measurement.

Current standard technique for venous pressure measurement is still invasive, requiring insertion of a catheter. Additionally, clinical estimation of central venous pressure (CVP) has proven unreliable compared to invasive methods. Meanwhile, different non-invasive ultrasound guided modalities may provide a valid alternative to invasive venous pressure measurement. Particularly promising is a novel compression ultrasound (CUS) which combines ultrasound properties with a tissue pressure manometer enabling even further future applications. This review provides an overview using ultrasound guided non-invasive venous pressure measurement (UGPni) in clinical trials so far and focuses on three objectives: (1) To summarize the main methods using UGPni for central venous pressure measurement (2) To outline the key findings of previous clinical trials for UGPni regarding CVP measurement with primary focus on novel compression ultrasound of a forearm vein (3) To point out limitations and possible future clinical implications of these ultrasound modalities UGPni represents an easy-to-perform and safe alternative to invasive "gold standard" diagnostic tools for measuring central venous pressure. After a brief introduction, non-specialist personnel using a portable ultrasound device can apply this method in a feasible way. Of all mentioned methods in this review CUS is the method of choice underscoring its ability to assess a patient's CVP categories correctly. Furthermore, detection of non-invasive central venous pressure in the emergency room represents an independent predictor for cardiac rehospitalization in patients with decompensated heart failure, thus helping in risk stratification as well as being an additive tool in general hemodynamic management of critically ill patients. This review concludes a significant role for ultrasound guided non-invasive venous pressure measurement suitable for a wide range of everyday clinical practice. However, further studies are warranted to proof a causal relationship in this regard.

External stenting and disease progression in vein grafts 1 year after open surgical repair of popliteal artery aneurysm.

OBJECTIVE: Open surgical repair remains the gold standard treatment for popliteal artery aneurysms (PAA). The objective of this study was to evaluate the safety of external stenting and its medium-term effect on vein graft disease after open PAA repair. METHODS: Between December 2017 and September 2019, 12 consecutive patients with PAA underwent open surgical repair with externally stented saphenous vein grafts. Duplex ultrasound scanning of the grafts was performed at discharge and at 3, 6, and 12 months after the procedure to evaluate graft patency, average lumen diameter and lumen uniformity. RESULTS: Eleven patients underwent aneurysm ligation and bypass grafting and one patient was treated with aneurysm exclusion and interposition of a venous segment. External stenting of the vein graft was successful in all patients. The mean follow-up time was 12 months (range, 7-17 months), with a primary patency rate of 100% and no graft revisions or reinterventions. The mean lumen diameters at 3, 6, and 12 months were 5.9 ± 1.2 mm, 5.7 ± 0.8 mm, and 5.7 ± 0.7 mm, respectively, with no significant changes between 3 and 6 (P = .34) and between 6 and 12 months (P = .34). The coefficient of variance at 3, 6, and 12 months was 8.2 ± 9.3, 9.4 ± 7.2, and 10.4 ± 8.9, respectively, with no significant change between 3 and 6 months (P = .78) or 6 and 12 months (P = .98). No mortality or amputations were recorded throughout the follow-up period. CONCLUSIONS: External stenting of vein grafts in open surgical repair of PAA is feasible and safe. This technique may potentially improve the outcomes of surgical repair in patients with PAA.

PAD screening: why? whom? when? how? - a systematic review.

An estimated 237 million people suffer from peripheral arterial disease (PAD), which is associated with high morbidity and mortality, and prevalence is still increasing. Currently, we do not have any randomized trials that compare screening to no screening specifically for PAD in the general population. Presently, PAD screening is not generally established. This systematic review gives an overview of relevant literature and guidelines. Screening usually focuses on ankle-brachial index (ABI)-measurement, which enables detection of asymptomatic and symptomatic PAD, but has limitations in diabetics. There are no sufficient data on PAD screening. Guideline recommendations are heterogeneous. While some advocate no screening until better data are available, most recommend selective screening despite insufficient data on morbidity and mortality reduction in consequence of screening. We support the only evidence-based screening strategy for PAD: combined screening for abdominal aortic aneurysm (AAA), PAD and arterial hypertension in men aged 65-74 according to the VIVA study. We additionally suggest a new simple three-step screening strategy for symptomatic PAD in all individuals aged 40 and older, who see a general practitioner: Asking one question ("Do you have pain or cramps in the legs during normal walking?") followed by physical examination (normal lower extremity pulse status?) in those, whose answer is "yes", and ABI measurement unless all pulses are normal.

Exercise induced leg pain due to endofibrosis of external iliac artery.

Due to monotonous movement patterns, muscular hypertrophy, and increased cardiac output peripheral vasculature of athletes are subject to extreme stresses during athletic performance. Individuals suffering from exercise induced non-traumatic lower leg pain may display underlying vascular pathology such as external iliac artery endofibrosis. Therefore, it is essential in the course of to discriminate vascular from non-vascular findings and prime the correct diagnostic path within the course of clinical examination. In this regard, interdisciplinary thinking and profound knowledge in exercise-associated pathologies of the musculoskeletal, nervous and vascular system is indispensable. Consequently, provocation testing displays an indispensable diagnostic tool and has to be continued until symptoms occur, or complete exhaustion is attained. Finally, selective assessment of conservative and surgical treatment options, as well as its ethical evaluation, are of major importance in order to protect, preserve and promote the health and physical integrity of our patients who are keen to perform.

Symptomatic type I endoleak following popliteal artery aneurysm repair.

A case of a symptomatic type Ib endoleak following popliteal artery aneurysm repair with successful interventional therapy introduces a short review of the limited literature to this relevant potential complication. Illustration of important factors supporting endoleak formation after endovascular popliteal artery repair and recommendation of a consequent surveillance are discussed.

Prevalence of carotid plaque stenosis after head and neck radiotherapy - an observational study of 156 survivors.

Background: Radiotherapy for head and neck cancer (HNC) represents a well-known predisposing factor for asymptomatic carotid artery lesions and acute cerebrovascular accidents. Our aim is to provide contemporary estimates on the prevalence, severity, and characteristics of carotid artery lesions in HNC survivors. Patients and methods: We prospectively included HNC patients who underwent radiotherapy and were free from the disease at the time of duplex ultrasound evaluation. Patients were re-contacted telephonically and those who agreed to participate were invited for an ambulatory visit when the investigators collected clinical information and performed duplex ultrasound examination based on a predefined protocol. Results: A total of 156 patients were included and underwent duplex ultrasound examination after a mean of 65.2 months from the last session of radiotherapy. A total of 36 patients (23.1%) had normal carotid arteries; mild, non-stenotic lesions were observed in 49.4% (n = 77) of patients; severe stenotic plaques were found in 27.5% (n = 43) of patients. One patient found with an asymptomatic occlusion of the left ICA. The prevalence of major cardiovascular risk factors and high radiation dose increased proportionally with plaque severity. Low echogenicity plaque was found in 59 (37.8%) patients on the right side and 57 (36.5%) on the left side; long segment plaque in 49 (31.4%) patients on the right side and in 47 (30.1%) on the left side; an atypical location of the lesions in 42 (26.9%) patients on the right side and in 48 (30.8%) on the left side. Conclusions: The prevalence of occlusion and severe stenosis after radiotherapy for HNC was very low in our study population. Low echogenicity plaque, long segment plaque, and an atypical location were common findings. Classic cardiovascular risk factors appear to have had a causative role: a routine screening of radiotherapy-treated patients might be necessary only in patients with concomitant cardiovascular risk factors or exposed to high-dose neck radiation.

Non-invasive ultrasound-based imaging of atherosclerosis.

Early detection of vascular damage in atherosclerosis and accurate assessment of cardiovascular risk factors are the basis for appropriate treatment strategies in cardiovascular medicine. The current review focuses on non-invasive ultrasound-based methods for imaging of atherosclerosis. Endothelial dysfunction is an accepted early manifestation of atherosclerosis. The most widely used technique to study endothelial function is non-invasive, flow-mediated dilation of the brachial artery under high-resolution ultrasound imaging. Although an increased intima-media thickness value is associated with future cardiovascular events in several large population studies, systematic use is not recommended in clinical practice for risk assessment of individual persons. Carotid plaque analysis with grey-scale median, 3-D ultrasound or contrast-enhanced ultrasound are promising techniques for further scientific work in prevention and therapy of generalized atherosclerosis.

Percutaneous sclerotherapy for spongiform venous malformations - analysis of patient-evaluated outcome and satisfaction.

BACKGROUND: Congenital venous malformations are frequently treated with sclerotherapy. Primary treatment goal is to control the often size-related symptoms. Functional impairment and aesthetical aspects as well as satisfaction have rarely been evaluated. PATIENTS AND METHODS: Medical records of patients who underwent sclerotherapy of spongiform venous malformations were reviewed and included in this retrospective study. The outcome of sclerotherapy as self-reported by patients was assessed in a 21 item questionnaire. RESULTS: Questionnaires were sent to 166 patients with a total of 327 procedures. Seventy-seven patients (48 %) with a total of 159 procedures (50 %) responded to the survey. Fifty-seven percent of patients were male. The age ranged from 1 to 38.1 years with a median age of 16.4 years. The lower extremities were the most common treated area. Limitations caused by the venous malformation improved in the majority of patients (e.g. pain improvement 87 %, improvement of swelling 83 %) but also worsening of symptoms occurred in a minority of cases. Seventy-seven per cent would undergo sclerotherapy again. CONCLUSIONS: Sclerotherapy for treatment of venous malformations results in significant reduction of symptoms. Multiple treatments are often needed, but patients are willing to undergo them.

Long-term follow-up after endovascular revascularisation for acute limb ischaemia--a retrospective single-centre cohort.

BACKGROUND: We evaluated the long-term outcome after endovascular revascularisation for acute limb ischaemia (ALI). PATIENTS AND METHODS: From a prospectively maintained database, 318 endovascular interventions for ALI were identified between 2004 and 2010. Event history and survival were analysed using the Kaplan-Meier method and Cox regression. Endpoints were target vessel revascularisation (TVR), non-target extremity revascularisation (NTER), amputation, major vascular events, coronary artery revascularisation and amputation-free survival. RESULTS: Follow-up data of 303 patients (mean age 68.5 ± 12.7 years, 40% female) were available. The mean follow-up time was 38.7 ± 26.2 months. TVR was performed in 40.1 ± 2.9% at 1 year and 66.5 ± 3.8% at 5 years. NTER at 1 and 5 years were 7.1 ± 1.5% and 29.2 ± 4%, respectively. The proportion of patients who needed major or minor amputation was 4.3 ± 1.2% after 1 year and 9 ± 2.1% after 5 years. Amputation-free survival at 1 year was 90.3 ± 1.8% and 74.8 ± 3.2% at 5 years. Coronary artery disease (HR 2.22, 95% CI 1.33 to 3.7, p = 0.002) and atrial fibrillation (HR 2.56, % CI 1.3 to 5.04, p = 0.007) were independently associated with a worse amputation-free survival. The cumulative proportion surviving one year following acute limb ischemia was 95.4 ± 1.2% and 79.7 ± 3.1% after 5 years. CONCLUSIONS: Long-term amputation-free survival after successful revascularisation for ALI is high; negative predictors are coronary artery disease and atrial fibrillation.

Vertebral and internal mammary artery steal syndrome in patients with hemodialysis access.

BACKGROUND: Increased flow in the subclavian artery feeding a vascular access for hemodialysis can induce steal phenomena in the vertebral (VA) and internal mammary artery (IMA). The aim of this study was to describe the hemodynamic effects of access flow on the VA and IMA in patients with native fistulas and grafts. PATIENTS AND METHODS: Peak systolic (PSV) and end diastolic (EDV) velocity measurements of the VA, IMA and carotid arteries, as well as flow volume measurements of the subclavian artery, were performed. Flow measurements at the side of the vascular access were compared with the contralateral side. Fifty-five patients were consecutively included, most with a radio-cephalic fistula on the left arm with a mean shunt volume of 1156 ml/min. RESULTS: Pathologic flow patterns were observed in the ipsilateral VA in four patients (7.3 %); contralateral VA flow was normal in all patients. Peak systolic velocity of the VA was significantly decreased at the side of the shunt arm with a PSV of 42.6 ± 11.8 cm/s compared to 48.4 ± 15.6 cm/s contralateral (p < 0.05). The IMA flow pattern were normal in all patients. The PSV of the IMA was significantly decreased (p < 0.01) at the side of the shunt arm (87.5 ± 29.1 cm/s) compared to the non-shunt arm (95.9 ± 27.4 cm/s). CONCLUSION: We describe significant hemodynamic effects of fistulas to the vertebral and internal mammary arteries. Doppler spectral analysis of the vertebral and internal mammary arteries should be integrated in ultrasound, especially in patients with cerebrovascular or cardiac symptoms.

Acute effects of haemodialysis on central venous and arterial pressure characteristics.

AIM: Haemodynamic stability of patients during haemodialysis (HD) sessions is of pivotal importance and accurate determination of dry weight remains a challenge. Little information is available about central venous and aortic pressure during dialysis. In this pilot study we used a non-invasive technique to describe the changes in central venous pressure (CVP) during dialysis. METHODS: An ultrasound-assisted pressure-manometer was used at the cephalic vein during haemodialysis to quantify CVP. Central aortic pressure changes were assessed as aortic augmentation index and subendocardial viability ratio. Bioimpedance was applied to measure total body water, as well as extracellular and intracellular water before and after HD. Measurements were performed prior during and after 1 and 2 h on HD. RESULTS: Ten patients were included with a median age of 72 years (23-82). Haemodialysis reduced the weight by 2.0 kg, corresponding to a measured decrease in total body water of 1.9 L. The mean CVP showed a significant decrease (9.0-0.8 cmH2O; P = 0.0005) during dialysis. The significant drop in CVP was found during the first hour (9-2.8 cmH2O). Starting and stopping dialysis was reflected by a reduction of 2.6 cmH2O and a rise of 2.8 cmH2O (n.s.). Aortic augmentation index decreased from 26.1% to 21.0% (n.s.). Subendocardial viability ratio increased from 126% to 156% (P < 0.05) during HD, and decreased to 139% direct after HD (n.s.). CONCLUSION: This is the first study that illustrates a prominent reduction of CVP during the first hour of haemodialysis. Non-invasive CVP measurement is feasible during haemodialysis and adds another piece in the puzzle of factors involved in haemodynamic stability.

Markers of arterial stiffness in peripheral arterial disease.

Increased arterial stiffness results from reduced elasticity of the arterial wall and is an independent predictor for cardiovascular risk. The gold standard for assessment of arterial stiffness is the carotid-femoral pulse wave velocity. Other parameters such as central aortic pulse pressure and aortic augmentation index are indirect, surrogate markers of arterial stiffness, but provide additional information on the characteristics of wave reflection. Peripheral arterial disease (PAD) is characterised by its association with systolic hypertension, increased arterial stiffness, disturbed wave reflexion and prognosis depending on ankle-brachial pressure index. This review summarises the physiology of pulse wave propagation and reflection and its changes due to aging and atherosclerosis. We discuss different non-invasive assessment techniques and highlight the importance of the understanding of arterial pulse wave analysis for each vascular specialist and primary care physician alike in the context of PAD.

Carotid artery disease after head and neck radiotherapy.

Radiation induced atherosclerosis of the carotid artery is a clinically relevant late complication after head and neck radiotherapy. Improved long-term survival after multimodality therapy in neck malignancies result in an increased risk of carotid artery disease in patients after radiotherapy (RT). This review focuses on the current knowledge of occlusive carotid disease after head and neck radiotherapy and highlights the exceeding morphologic post-radiation vessel wall pathologies. More severe and extensive carotid artery atherosclerosis with plaque in all segments including the common carotid artery is a frequent finding after RT. Therefore, colour coded duplex ultrasound surveillance in patients after head and neck RT is recommended. Some histopathological studies indicate differences to “classical” atherosclerosis, and pathogenesis of chronic radiation vasculopathy is still under discussion.

Vascular accesses for hemodialysis - an update.

During the last two decades the prevalence of patients needing chronic renal replacement therapy has increased progressively. Furthermore, the dialysis population has significantly changed. Patients are older, have multiple comorbidities, and have a particularly high cardio-vascular risk. Therefore, the prerequisites for the formation of fistulae have become worse. Many centres (including our own) have formed interdisciplinary vascular access teams to provide an optimal service for these patients. Herein, we review recent studies regarding the diagnostic and therapeutic approaches for access failure. As many clinical decisions remain opinion -based we also include our personal approach resulting from regular interdisciplinary board meetings.

Association of Intrarenal Resistance Index and Systemic Atherosclerosis After Kidney Transplantation.

BACKGROUND/AIM: Patients after kidney transplants are at risk of cardiovascular morbidity. An elevated resistance index (RI) is associated with renal graft failure, while a decreased RI can be due to a renal artery stenosis. The RI can also be measured in the carotid artery. Whether a correlation between intrarenal RI after kidney transplant in adult patients and the RI of the internal carotid artery exists is still unclear. PATIENTS AND METHODS: In this prospective cross-sectional study, RI of kidney transplants and of the internal carotid artery were measured with duplex sonography. Carotid intima-media thickness as well as the Framingham risk score and the Augmentation index, all known markers of atherosclerosis, were assessed. Correlations between the RI in Carotid artery and the RI of the kidney transplant were based on Spearmen test with the level of significance set at p<0.05. RESULTS: Ninety-eight consecutive patients [60% male, mean age of 48.7 (±15.6)] were included. The mean interval after transplantation was 27.5 (±8.5) months and mean serum creatinine was 308 (±220.3) mmol/ml The RI of the internal carotid artery and the renal transplant were significantly correlated (p<0.05). A correlation between the RIs and the Augmentation Index was found. CONCLUSION: The RI of the kidney transplant is correlated with the RI of the carotid artery and to markers of general atherosclerosis. This observation may be helpful to identify patients after kidney transplant with higher risk for cardiovascular events and gain indirect information on transplant renal artery stenosis.