Endovascular versus medical treatment of venous compression syndrome of the iliac vein - a systematic review.

The treatment of non-thrombotic iliac vein lesions (NIVL) remains debatable with many advocating conservative treatments, whilst others offering venous stenting. The objective of this review was to systematically assess the treatment options for symptomatic iliac vein compression syndrome (IVCS) in patients without evidence of thrombotic disease at the time of diagnosis. An online search of published literature looking for randomised controlled trials and observational studies that evaluated the treatment for symptomatic NIVL was performed. Nine studies were included with a total 953 patients of which 782 patients had NIVL. Patency rates ranged between 94.8%-100% in the first month, 88.2%-94.1% in six months and 73.4%-98% in 12 months, in patients with NIVL post stenting. Longer follow-up of up to 5 years shows promising patency rates of 94% in patients with IVCS. Patients with IVCS are likely to benefit from a combination of endovenous treatment at the time of diagnosis including stent placement to maintain lumen patency and prevent recurrent deep venpus thrombosis and/or postthrombotic syndrome.

End-To-Side versus Side-To-Side Anastomosis in Upper Limb Arteriovenous Fistula for Dialysis Access: A Systematic Review and a Meta-Analysis.

BACKGROUND: An arteriovenous fistula (AVF) is the best modality for hemodialysis access. The end-to-side (ETS) technique has been suggested in the literature to produce superior results to the side-to-side (STS) approach; however, in the absence of a systematic review, this practice remains debatable. METHODS: Online search for randomized controlled trials and observational studies that compared the ETS versus the STS anastomosis techniques in creating an upper limb AVF. Aims were to systematically assess the difference between both procedures in terms of access maturation, patency, and postoperative complications. RESULTS: Seven studies were included with 463 patients in the ETS group and 523 in the STS group. The difference between the 2 techniques was not significant in relation to patency rates at 3, 6, 12, and 24 months (P values: 0.28, 0.82, 0.54, and 0.21, respectively). There were fewer cases of postoperative hematoma in the ETS group; however, the difference was not significant (P = 0.09). Arterial steal syndrome was found to be significantly associated with the STS configuration in pooled analysis (pooled risk ratio = 0.11 [0.01-0.88], 95% CI, P = 0.04). CONCLUSIONS: Similar maturation rates between ETS and STS fistula configuration, however, arterial steal syndrome was significantly associated with the STS technique. ETS will likely remain as the preferred AVF configuration as it is less technically demanding.

Supervised exercise therapy in the management of peripheral arterial disease - an assessment of compliance.

BACKGROUND: Supervised exercise therapy (SET) is an effective option in the management of peripheral arterial disease (PAD). Unfortunately, poor compliance remains prevalent. This study aimed to assess patient exercise compliance and to identify factors influencing symptomatic improvement and SET participation. PATIENTS AND METHODS: Data regarding attendance at SET for this cohort study were extracted from a prospectively maintained database of patients with claudication attending SET at Dublin City University. All patients had ankle brachial index confirmed PAD with associated intermittent claudication. Exercise performance and symptomatic data were gathered retrospectively using patient charts and interviews. RESULTS: Ninety-eight patients were referred for SET during the study period. The mean age was 69.2 (± 10.1) with 18 % being female. Median follow-up was 25.1 months (IQ range 17.0-31.6). Overall, the mean number of sessions attended per patient was 19.5. Exercise compliance was associated with a significant improvement in symptoms (p = 0.001). Other factors including anatomical level of claudication (P = 0.042) and educational level (p = 0.007) were found to affect the outcome of SET. Multivariate analysis revealed hypertension as a predictor of symptomatic outcome after SET (p = 0.045). Furthermore, ex-smokers (p = 0.021) and those previously diagnosed with hypercholesterolaemia (p = 0.020) or ischaemic heart disease (p = 0.029) had superior exercise compliance. Using linear regression, smoking history (p = 0.024) was identified as a predictor of compliance to SET. CONCLUSIONS: Establishing exercise compliance remains challenging in the PAD cohort. Pre-exercise patient education and personalised exercise prescriptions may result in improvements in function and compliance.

The Use of Intermittent Pneumatic Compression in Orthopedic and Neurosurgical Postoperative Patients: A Systematic Review and Meta-analysis.

OBJECTIVE: The objective of this systematic review and meta-analysis was to carry out an up-to-date evaluation on the use of compression devices as deep vein thrombosis (DVT) prophylaxis methods in orthopedic and neurological patients. SUMMARY OF BACKGROUND DATA: There is an increased risk of DVT with surgery, particularly in patients who are not expected to mobilize soon after their procedures, such as orthopedic and neurosurgical patients. Compression devices are often employed for DVT prophylaxis in these patients. However, the true efficacy of these devices and the standardization of use with these devices are yet to be established. METHODS: Medline, CINAHL, Embase, Google Scholar, and the Cochrane library electronic databases were searched to identify randomized controlled trials and observational studies reporting on the use of compression devices for DVT prevention. RESULTS: Nine studies were included for review and meta-analysis. Use of an intermittent pneumatic compression device alone is neither superior nor inferior to chemoprophylaxis. CONCLUSIONS: In the absence of large randomized multicenter trials comparing the use of intermittent pneumatic compression or chemoprophylaxis alone to a combination of both treatments, the current evidence supports the use of a combined approach in high-risk surgical patients.

Can a Neutrophil-Lymphocyte Ratio Derived from Preoperative Blood Tests Predict Arteriovenous Fistula Maturation?

BACKGROUND: To evaluate the association between inflammatory markers expressed as neutrophil-lymphocyte ratio (NLR) and process of arteriovenous fistula (AVF) maturation. METHODS: A retrospective review of patients with end-stage renal disease referred for formation of a new AVF in one center. Patients referred to the vascular service in the University Hospital of Limerick for creation of vascular access between 2009 and 2013. The association between NLR, calculated from preoperative blood tests, and functional fistula maturation, as determined by successful use of the AVF for 6 consecutive hemodialysis sessions, was investigated using univariate and logistic regression analyses. A logistic regression analysis was carried out to assess potential influence from other factors related to AVF maturation. Stepwise regression test was performed including the NLR. RESULTS: Overall AVF functional maturation rate in our study was 53.7% (66/123). Patients with matured AVFs had an NLR of 4.850 (1.8-15.7) compared with 3.554 (1.7-15.0); this difference was found to be significant (P = 0.024). Female gender (P = 0.008) and a history of kidney transplant (P = 0.004) were the only independent factors of fistula maturation outcome in a logistic regression model. CONCLUSION: Increased level of NLR was found to be associated with fistula maturation; however, more studies are needed to validate this finding.

Arteriovenous fistula in dialysis patients: Factors implicated in early and late AVF maturation failure.

Increasing numbers of patients are being diagnosed with end-stage renal disease (ESRD), and the demand for on haemodialysis (HD) is rising. Arteriovenous fistulae (AVFs) remain the best conduit for adequate HD, with fewer complications associated with long-term use compared to bypass grafts and central venous catheters. However, it is known that many newly formed fistulae do not mature to provide useful HD access. The paper provides a narrative overview of factors influencing the process of AVF maturation failure.

Evidence for varicose vein surgery in venous leg ulceration.

BACKGROUND: Venous leg ulcers affect 1-3% of adults with a significant economic impact, utilizing 1% of annual healthcare budgets in some western European countries. OBJECTIVES: To determine the effects of intervention for incompetent superficial veins on ulcer healing and recurrence in patients with active or healed venous ulcers. SEARCH METHODS: In October 2014, we searched Medline, CINAHL, EMBASE, Scopus, the Cochrane library and Web of Science without date or language restriction for relevant randomized or observational studies. Bibliographies of included studies were also searched for additional studies. SELECTION CRITERIA: Observational studies or randomized controlled trials comparing intervention for varicose veins with compression therapy alone for venous leg ulcers were eligible. In addition, studies compared open to endovenous therapy for varicose veins in patients with leg ulcers and those compared treating saphenous and perforating veins to treating saphenous veins only were also included. Studies had to report at least one ulcer-related outcome (healing rate, recurrence or time to healing). DATA COLLECTION AND ANALYSIS: Details of potentially eligible studies were extracted and summarized using a data extraction table. Data extraction and quality assessment were performed independently by two review authors, and any disagreements resolved by consensus or by arbitration of a third author. RESULTS: Intervention for superficial venous reflux improved ulcer healing (risk ratio = 1.11 [1.00, 1.22], 95% CI, p = 0.04) and reduced recurrence (risk ratio = 0.48 [0.32, 0.67], 95% CI, p < 0.0001) compared to compression alone, with low level of evidence. CONCLUSION: This review confirmed that the evidence for a beneficial effect of endovenous and open surgery for varicose vein in venous leg ulcer is at beast weak. A well-structured RCT is required to investigate the role of endovenous ablation of incompetent superficial veins in improving venous leg ulcer outcomes.

Does longitudinal or transverse orientation of the ultrasound probe improve cannulation success in minimally invasive venous surgery: A multicentre randomised controlled trial.

OBJECTIVE: This study evaluates the effect of transverse and longitudinal ultrasound transducer orientation on saphenous vein cannulation during endovenous ablation. METHODS: A single-blinded, multicentre, randomised controlled trial was performed in patients undergoing ultrasound-guided venous cannulation for saphenous ablation. The primary outcomes were overall cannulation success and time to successful cannulation. RESULTS: In total, 100 patients were assigned to parallel longitudinal orientation and transverse orientation groups. Cannulation success was 100%. There was no significant variation in time to cannulation detected between the transverse orientation and longitudinal orientation (85 s vs. 71 s, p = 0.314). Longitudinal orientation was associated with significantly fewer needle passes [median 3 (interquartile range 1-5) vs. 2 (interquartile range 1-3), p = 0.026] and less pain (median visual analogue scale score 1 vs. 2.5, p = 0.039) than those in the transverse orientation group. CONCLUSION: This trial has shown that while longitudinal orientation is associated with less procedural pain it has no significant effect on time to target vein cannulation during endovenous ablation.

Reducing Surgical Site Infections in Abdominal Surgery: Are Ring Retractors Effective? A Systematic Review and Meta-Analysis.

BACKGROUND: Surgical site infection (SSI) is one of the main causes of morbidity and death after surgical intervention. The use of physical barriers, including gloves, drapes, and gowns to reduce SSI after abdominal surgery is long-standing practice. The aim of this systematic review and meta-analysis was to determine the efficacy of ring incision retractors in reducing the risk of SSI in abdominal surgery. METHODS: PubMed, CINAHL, the Cochrane randomized controlled trials (RCTs) Central Register, and the ISRCTN registry were searched for RCTs in which ring retractors were utilized to reduce SSI in abdominal surgery. The PRISMA guidelines and RevMan 5.3 were used for study selection and analysis. Additional subgroup analyses were performed, including trials using incision class (clean, clean-contaminated contaminated, and dirty) and trials that used the U.S. Centers for Disease Control and Prevention's SSI definition in their protocol. RESULTS: A total of 19 RCTs inclusive of 4,229 patients were included. The utility of ring retractors in reducing SSI was suggested by an overall risk ratio of 0.62 (95% confidence interval 0.48-0.81). However, study heterogeneity caused by differences in effect size between individual RCTs, the non-standardized utilization of concomitant measures to reduce SSI, and an overall lack of high-quality trials was found. CONCLUSION: A reduction in SSI incidence with the use of ring retractors is suggested by the findings. However, this result must be treated with caution because in addition to some old trials poor quality and the large number of factors affecting SSI, there were substantial differences between trials in effect sizes in statistical heterogeneity. Further RCTs are needed to confirm this provisional finding.

The Role of Shear Stress in Arteriovenous Fistula Maturation and Failure: A Systematic Review.

INTRODUCTION: Non-maturation and post-maturation venous stenosis are the primary causes of failure within arteriovenous fistulae (AVFs). Although the exact mechanisms triggering failure remain unclear, abnormal hemodynamic profiles are thought to mediate vascular remodelling and can adversely impact on fistula patency. AIM: The review aims to clarify the role of shear stress on outward remodelling during maturation and evaluate the evidence supporting theories related to the localisation and development of intimal hyperplasia within AVFs. METHODS: A systematic review of studies comparing remodelling data with hemodynamic data obtained from computational fluid dynamics of AVFs during and after maturation was conducted. RESULTS: Outward remodelling occurred to reduce or normalise the level of shear stress over time in fistulae with a large radius of curvature (curved) whereas shear stress was found to augment over time in fistulae with a small radius of curvature (straight) coinciding with minimal to no increases in lumen area. Although this review highlighted that there is a growing body of evidence suggesting low and oscillating shear stress may stimulate the initiation and development of intimal medial thickening within AVFs. Further lines of evidence are needed to support the disturbed flow theory and outward remodelling findings before surgical configurations and treatment strategies are optimised to conform to them. This review highlighted that variation between the time of analysis, classification of IH, resolution of simulations, data processing techniques and omission of various shear stress metrics prevented forming pooling of data amongst studies. CONCLUSION: Standardised measurements and data processing techniques are needed to comprehensively evaluate the relationship between shear stress and intimal medial thickening. Advances in image acquisition and flow quantifications coupled with the increasing prevalence of longitudinal studies commencing from fistula creation offer viable techniques and strategies to robustly evaluate the relationship between shear stress and remodelling during maturation and thereafter.

In vivo validation of the in silico predicted pressure drop across an arteriovenous fistula.

The creation of an arteriovenous fistula offers a unique example of vascular remodelling and adaption. Yet, the specific factors which elicit remodelling events which determine successful maturation or failure have not been unambiguously determined. Computational fluid dynamic (CFD) simulations are increasingly been employed to investigate the interaction between local hemodynamics and remodelling and can potentially be used to assist in clinical risk assessment of maturation or failure. However, these simulations are inextricably linked to their prescribed boundary conditions and are reliant on in vivo measurements of flow and pressure to ensure their validity. The study compares in vivo measurements of the pressure distribution across arteriovenous fistulae against a representative numerical model. The results of the study indicate relative agreement (error ≈ 8-10%) between the in vivo and CFD prediction of the mean pressure drop across the AVFs. The large pressure drop across the AVFs coincided with a palpable thrill (perivascular vibration) in vivo and fluctuations were observed in the numerical pressure drop signal due to flow instabilities arising at the anastomosis. This study provides a benchmark of the pressure distribution within an AVF and validates that CFD solutions are capable of replicating the abnormal physiological flow conditions induced by fistula creation.

Predictive parameters of arteriovenous fistula functional maturation in a population of patients with end-stage renal disease.

INTRODUCTION: With increasing numbers of patients diagnosed with ESRD, arteriovenous fistula (AVF) maturation has become a major factor in improving both dialysis related outcomes and quality of life of those patients. Compared to other types of access it has been established that a functional AVF access is the least likely to be associated with thrombosis, infection, hospital admissions, secondary interventions to maintain patency and death. AIM: Study of demographic factors implicated in the functional maturation of arteriovenous fistulas. Also, to explore any possible association between preoperative haematological investigations and functional maturation. METHODS: We performed a retrospective chart review of all patients with ESRD who were referred to the vascular service in the University Hospital of Limerick for creation of vascular access for HD. We included patients with primary AVFs; and excluded those who underwent secondary procedures. RESULTS: Overall AVF functional maturation rate in our study was 53.7% (52/97). Female gender showed significant association with nonmaturation (P = 0.004) and was the only predictor for non-maturation in a logistic regression model (P = 0.011). Patients who had history of renal transplant (P = 0.036), had relatively lower haemoglobin levels (P = 0.01) and were on calcium channel blockers (P = 0.001) showed better functional maturation rates. CONCLUSION: Female gender was found to be associated with functional non-maturation, while a history kidney transplant, calcium channel-blocker agents and low haemoglobin levels were all associated with successful functional maturation. In view of the conflicting evidence in the literature, large prospective multi-centre registry-based studies with well-defined outcomes are needed.

One-stage vs. two-stage brachio-basilic arteriovenous fistula for dialysis access: a systematic review and a meta-analysis.

INTRODUCTION: A brachiobasilic arteriovenous fistula (BB-AVF) can provide access for haemodialysis in patients who are not eligible for a more superficial fistula. However, it is unclear whether one- or two-stage BB-AVF is the best option for patients. AIM: To systematically assess the difference between both procedures in terms of access maturation, patency and postoperative complications. METHODS: Online search for randomised controlled trials (RCTs) and observational studies that compared the one-stage versus the two-stage technique for creating a BB-AVF. RESULTS: Eight studies were included (849 patients with 859 fistulas), 366 created using a one-stage technique, while 493 in a two-stage approach. There was no statistically significant difference between the two groups in the rate of successful maturation (Pooled risk ratio = 0.95 [0.82, 1.11], P = 0.53). Similarly, the incidence of postoperative haematoma (Pooled risk ratio = 0.73 [0.34, 1.58], P = 0.43), wound infection (Pooled risk ratio = 0.77 [0.35, 1.68], P = 0.51) and steal syndrome (Pooled risk ratio = 0.65 [0.27, 1.53], P = 0.32) were statistically comparable. CONCLUSION: Although more studies seem to favour the two-stage BVT approach, evidence in the literature is not sufficient to draw a final conclusion as the difference between the one-stage and the two-stage approaches for creation of a BB-AVF is not statistically significant in terms of the overall maturation rate and postoperative complications. Patency rates (primary, assisted primary and secondary) were comparable in the majority of studies. Large randomised properly conducted trials with superior methodology and adequate sub-group analysis are needed before making a final recommendation.

Cerebral hypoperfusion secondary to radiation arteritis presenting with recurrent syncope.

Radiation arteritis can lead to significant extracranial carotid artery stenosis, affecting the circle of Willis. Cerebral hypoperfusion due to arterial insufficiency is often considered as a differential diagnosis in cases of syncope but rarely proven. We present a case of a 61-year-old man with repeated episodes of syncope-negative cardiac investigations. He had a history of cervical radiation therapy for tonsillar squamous cell carcinoma 15 years previously. Carotid duplex revealed bilateral carotid occlusive disease. MR angiography showed severe multilevel extracranial carotid stenosis bilaterally with occluded left vertebral artery. A diagnosis of cerebral hypoperfusion was performed following single-photon emission CT scan. The patient underwent a left subclavian to carotid bypass, which alleviated his symptoms.

Pre-operative ultrasonography and arteriovenous fistulae maturation.

BACKGROUND: Arteriovenous fistulae (AVF) are preferred for haemodialysis access, but maturation is unpredictable. RESULTS: Clinical examination alone is unreliable for AVF planning. Duplex ultrasonography may provide useful anatomical and physiological data to allow more accurate prediction of likely AVF success. CONCLUSION: Selective use of duplex ultrasonography appears to enhance AVF success rates, but there are insufficient data to recommend routine duplex screening of AVF candidates. Agreed vessel criteria are needed.

Effects of neck radiation therapy on extra-cranial carotid arteries atherosclerosis disease prevalence: systematic review and a meta-analysis.

INTRODUCTION: Radiation arteritis following neck irradiation as a treatment for head and neck malignancy has been well documented. The long-term sequelae of radiation exposure of the carotid arteries may take years to manifest clinically, and extra-cranial carotid artery (ECCA) stenosis is a well-recognised vascular complication. These carotid lesions should not be regarded as benign and should be treated in the same manner as standard carotid stenosis. Previous studies have noted increased cerebrovascular events such as stroke in this cohort of patients because of high-grade symptomatic carotid stenosis resulting in emboli. AIM: To evaluate the effect of radiation therapy on ECCA atherosclerosis progression. METHODS: Online search for case-control studies and randomised clinical trials that reported on stenosis in extra-cranial carotid arteries in patients with neck malignancies who received radiation therapy (RT) comparing them to patients with neck malignancies who did not receive RT. RESULTS: Eight studies were included in the final analysis with total of 1070 patients - 596 received RT compared to 474 in the control group. There was statistically significant difference in overall stenosis rate (Pooled risk ratio  =  4.38 [2.98, 6.45], P  =  0.00001) and severe stenosis (Pooled risk ratio  =  7.51 [2.78, 20.32], P <0.0001), both being higher in the RT group. Pooled analysis of the five studies that reported on mild stenosis also showed significant difference (Pooled risk ratio  =  2.74 [1.75, 4.30], 95% CI, P  =  0.0001). CONCLUSION: The incidence of severe ECCA stenosis is higher among patients who received RT for neck malignancies. Those patients should be closely monitored and screening programs should be considered in all patients who receive neck RT.

Role of far infra-red therapy in dialysis arterio-venous fistula maturation and survival: systematic review and meta-analysis.

INTRODUCTION: A well-functioning arteriovenous fistula (AVF) is the best modality for vascular access in patients with end-stage renal disease (ESRD) requiring haemodialysis (HD). However, AVFs' main disadvantage is the high rate of maturation failure, with approximately one third (20%-50%) not maturing into useful access. This review examine the use of Far-Infra Red therapy in an attempt to enhance both primary (unassisted) and secondary (assisted) patency rates for AVF in dialysis and pre-dialysis patients. METHOD: We performed an online search for observational studies and randomised controlled trials (RCTs) that evaluated FIR in patients with AVF. Eligible studies compared FIR with control treatment and reported at least one outcome measure relating to access survival. Primary patency and secondary patency rates were the main outcomes of interest. RESULTS: Four RCTs (666 patients) were included. Unassisted patency assessed in 610 patients, and was significantly better among those who received FIR (228/311) compared to (185/299) controls (pooled risk ratio of 1.23 [1.12-1.35], p = 0.00001). In addition, the two studies which reported secondary patency rates showed significant difference in favour of FIR therapy--160/168 patients--compared to 140/163 controls (pooled risk ratio of 1.11 [1.04-1.19], p = 0.003). CONCLUSION: FIR therapy may positively influence the complex process of AVF maturation improving both primary and secondary patency rates. However blinded RCTs performed by investigators with no commercial ties to FIR therapy technologies are needed.