A comparison between intravascular ultrasound and venography in identifying key parameters essential for iliac vein stenting

Venous Insufficiency: Wound Management

PURPOSE OF REVIEW

Venous leg ulcers (VLUs) are one of the most common forms of chronic wounds and with nearly half the people having recurrent episodes, this significantly impacts a patient's quality of life. As such, VLU is a chronic disease that requires lifelong maintenance and awareness. A correct diagnosis of VLU is essential for management.

RECENT FINDINGS

VLUs can be of mixed etiology and treatment should be aimed at optimizing the underlying venous hypertension based on its cause. If there is an anatomical venous reflux contributing to the non-healing of the VLU, early treatment of incompetent veins can improve healing rates. All aspects contributing to the patient's ongoing venous hypertension should be addressed to provide appropriate treatment. This can include venous interventions but also through conservative measures. Patient education and their engagement in their own care is essential for good outcomes.

Inferior and Superior Vena Cava Reconstruction

Obstructions of the superior and inferior vena cava are prevalent etiologies of deep venous obstruction, presenting a spectrum of clinical manifestations ranging from life-threatening conditions to asymptomatic states. The etiological diversity inherent to these central venous obstructions necessitates a subtle approach to their diagnosis and management. This discrepancy in clinical presentations emphasizes the importance of a differentiated diagnostic and therapeutic strategy, tailored to the specific form of vena cava obstruction encountered. This article aims to delineate the various manifestations of vena cava obstruction and encourages specific diagnostic and treatment pathways.

Quantitative 2-Dimensionsal Digital Subtraction Venography for Venous Interventions: Validation in Phantom and In Vivo Porcine Models

PURPOSE

To determine the feasibility of using a 2-dimensional quantitative digital subtraction venography (qDSV) technique that employs a temporally modulated contrast medium injection to quantify blood velocity in phantom, normal, and stenotic porcine iliac vein models.

MATERIALS AND METHODS

Blood velocity was calculated using qDSV following temporally modulated pulsed injections of iodinated contrast medium and compared with Doppler ultrasound (US) measurements (phantom, in-line sensor; in vivo, diagnostic linear probe). Phantom evaluation was performed in a compliant polyethylene tube phantom with simulated venous flow. In vivo evaluation of qDSV was performed in normal (n = 7) and stenotic (n = 3) iliac vein models. Stenoses were created using endovenous radiofrequency ablation, and blood velocities were determined at baseline, after stenosis, after venoplasty, and after stent placement.

RESULTS

In the phantom model, qDSV-calculated blood velocities (12-50 cm/s) had very strong correlations with US-measured velocities (13-51 cm/s) across a range of baseline blood velocities and injection protocols (slope, 1.01-1.13; R2 = 0.96-0.99). qDSV velocities were similar to US velocities regardless of injection method: (a) custom injector, (b) commercial injector, or (c) hand injection. In the normal in vivo model, qDSV-calculated velocities (5-18 cm/s) had strong correlation (slope, 1.22; R2 = 0.90) with US-measured velocities (3-20 cm/s). In the stenosis model, blood velocities at baseline, after stenosis, after venoplasty, and after stent placement were similar on qDSV and US at all time points.

CONCLUSIONS

Venous blood velocity was accurately quantified in a venous phantom and in vivo porcine models using qDSV. Intraprocedural changes in porcine iliac vein blood velocity were quantified with qDSV after creation of a stenosis and subsequently treating it with venoplasty and stent placement.

Preliminary application of three-dimensional venography and fusion navigation technique in May-Thurner syndrome

OBJECTIVE

The purpose of this study was to report a technique for intraprocedural guidance of endovascular iliac vein stenting procedures using three-dimensional (3D) venography images as an overlay on live biplanar fluoroscopy.

METHODS

Using 3D venography and a fusion navigation technique, percutaneous transluminal angioplasty and stent placement were performed to evaluate the feasibility of using 3D venography images and the fusion navigation technique to treat MTS compared with traditional digital subtraction angiography. The general epidemiologic data (ie, age, gender), clinical manifestations (ie, major symptoms, affected extremity, CEAP [clinical, etiology, anatomy, pathophysiology] classification, comorbidity, stenosis rate), intraoperative findings (ie, stent type, stent count, stent to inferior vena cava distance, procedure time, radiation dose, contrast agent dosage), and postoperative recovery were obtained and analyzed.

RESULTS

A total of 30 consecutive patients with symptomatic MTS from our institution were enrolled in the present study. Of the 30 patients, 12 (group A) were treated using 3D venography images and fusion navigation and 18 (group B) were treated with two-dimensional venography images during endovascular management. Significant differences were observed between the two groups with respect to the procedure time (64.42 ± 4.35 minutes vs 76.61 ± 3.47 minutes; P = .04), radiation dose (2152 ± 124.7 mGy vs 2561 ± 105.6 mGy; P = .02), and contrast agent dosage (71.42 ± 4.87 mL vs 86.17 ± 4.14 mL; P = .03).

CONCLUSIONS

3D venography and its fusion navigation technique can improve prediction of the coverage area of the stent. Its use can also shorten the procedure time and reduce the contrast agent dose and radiation exposure, making it a valuable tool for both the diagnosis and the treatment of symptomatic MTS.

Diagnosis of chronic iliac venous obstruction

Stenting has become the first line of treatment for symptomatic chronic iliofemoral venous obstruction in patients with quality-of-life-impairing clinical manifestations who have failed conservative therapy. Patient selection for such intervention is, however, dependent on clear identification of relevant clinical manifestations and subsequent testing to confirm the diagnosis. In this regard, the physician engaged in management of such patients needs to be well-aware of symptoms and signs of chronic iliofemoral venous obstruction, and instruments used to grade chronic venous insufficiency and determine quality of life, in addition to diagnostic tests available and their individual roles. This review serves to provide an overview of the diagnosis of chronic iliofemoral venous obstruction and patient selection for stenting.

Percutaneous Image-Guided Treatment of Pediatric Deep-Vein Occlusions

Pediatric venous occlusions are a growing cause of morbidity and mortality, especially in hospitalized patients. Catheter-directed recanalization is a safe and effective treatment option in appropriately selected patients. Benefits of catheter directed therapies (CDTs) include the prevention of pulmonary embolism and end organ failure acutely as well as superior vena cava syndrome and post-thrombotic syndrome chronically. Timely diagnosis, recognition of underlying factors for thrombosis, and familiarity with the spectrum of tools and techniques for CDT are essential to optimizing outcomes in the acute setting. Recanalization of chronic venous occlusions can similarly provide symptomatic relief and achieve long term vessel patency. This review will detail the scope, techniques, and outcomes for CDT in the treatment of acquired systemic deep vein occlusions.

A meta-analysis of the medium- to long-term outcomes in patients with chronic deep venous disease treated with dedicated venous stents

OBJECTIVE

This review summarizes the safety profile, stent patency, and clinical effectiveness of dedicated venous stents for the treatment of chronic deep venous disease. The approaches to stenting and post-procedural management of different vascular units are also explored.

METHODS

The MEDLINE and Embase databases were searched for pertinent literature published from January 2010 to January 2023. Outcomes related to post-stenting symptoms and health-related quality of life were described narratively. A meta analysis was conducted to evaluate stent patency, ulcer healing, bleeding, and 30-day stent thrombosis, and these outcomes were presented as proportion event rates.

RESULTS

Seventeen studies were identified comprising of 2218 patients. 62.7% of individuals had post-thrombotic stenosis or occlusion. The majority of patients (78.6%) were noted to have complete occlusions of their deep veins before stenting. Eleven different dedicated venous stents were deployed. At 12 months, the primary patency rate was 83% (95% confidence interval [CI]: 76%-90%), the primary-assisted patency rate was 90% (95% CI: 85%-96%), and the secondary patency rate was 95% (95% CI: 92%-98%). A significant improvement in health-related quality of life was demonstrated after intervention. In total, 68.8% (95% CI: 52.0%-83.7%) of ulcers healed at the last follow-up. The remaining symptomatic changes were described narratively; improvements in pain, venous claudication, and edema after stenting were observed. Seventeen deaths occurred, but none were linked to the stenting procedures. A total of 159 cases (7.2% of patients) of in-stent stenosis were observed, whereas 110 stents (5.0% of patients) were occluded. The incidence of major and minor bleeding was 1.7% (95% CI: 1.0%-2.5%) and 3.2% (95% CI: 1.3%-5.6%), respectively, more commonly seen in patients undergoing hybrid intervention.

CONCLUSIONS

Deep venous stenting using dedicated venous stents is a safe technique to treat chronic deep venous stenosis and/or occlusion. Within the limitations of this study, deep venous stenting is associated with good patency rates and symptomatic improvement.

A cadaver study evaluating intraluminal anomalies of the left common iliac vein

OBJECTIVE

Intraluminal anomalies within the left common iliac vein, characteristic of iliac vein compression syndrome, are thought to result from compression by and pulsation of the overlying right common iliac artery. This cadaver study was designed to expand on the existing literature by surveying and photographing these spurs in addition to exploring whether certain factors, inherent to the cadaver, are associated with spur presence.

METHODS

Dissection to expose the aorta, inferior vena cava, and common iliac arteries and veins was performed in 51 cadavers. The spinal level at which the iliac vein confluence occurred was noted. The point at which the right common iliac artery crossed the left common iliac vein was examined for plaque presence. The overlying arterial structures were then transected to expose the venous system. The inferior vena cava was incised to facilitate observation into the mouth and full extent of the left common iliac vein. Spurs were photographed and documented. Statistical analysis was conducted to determine whether sex, body mass index (BMI), plaque presence, or level of the iliac vein confluence are associated with spur presence.

RESULTS

Spurs within the left common iliac vein were observed in 16 of 51 cadavers (31.4%). All spurs were located at the point that the right common iliac artery crossed the left common iliac vein. Using1 the classification system established by McMurrich, 67% of spurs (n = 10) were marginal and triangular; 25% (n = 4) were columnar. One marginal, linear spur (6%) and one partially obstructed spur with multiple synechiae (6%) were observed. Among this population, males were 73% less likely to have a spur (odds ratio, 0.269; P = .041). No significant relationship was found between plaque presence and spur presence (odds ratio, 0.933; P = .824) and no significant differences were noted between BMI and spur presence (χ2 = 1.752, P = .625). Last, a significantly greater percent of spurs was found within cadavers with an iliac vein confluence located at the L5/S1 disc space (χ2 = 9.650; P = .002).

CONCLUSIONS

Study findings show that spurs are more common when the confluence of the common iliac veins occurs at a lower spinal level. The level of the iliac vein confluence may be important in identifying patients at increased risk of venous disease. The findings also suggest that plaque within the right common iliac artery and BMI display no distinct relationship with spur presence. Further investigation is needed to understand exactly what factors lead to spur formation.

Intravascular Ultrasound Use in Peripheral Arterial and Deep Venous Interventions: Multidisciplinary Expert Opinion From SCAI/AVF/AVLS/SIR/SVM/SVS

Percutaneous revascularization is the primary strategy for treating lower extremity venous and arterial disease. Angiography is limited by its ability to accurately size vessels, precisely determine the degree of stenosis and length of lesions, characterize lesion morphology, or correctly diagnose postintervention complications. These limitations are overcome with use of intravascular ultrasound (IVUS). IVUS has demonstrated the ability to improve outcomes following percutaneous coronary intervention, and there is increasing evidence to support its benefits in the setting of peripheral vascular intervention. At this stage in its evolution, there remains a need to standardize the use and approach to peripheral vascular IVUS imaging. This manuscript represents considerations and consensus perspectives that emerged from a roundtable discussion including 15 physicians with expertise in interventional cardiology, interventional radiology, and vascular surgery, representing 6 cardiovascular specialty societies, held on February 3, 2023. The roundtable's aims were to assess the current state of lower extremity revascularization, identify knowledge gaps and need for evidence, and determine how IVUS can improve care and outcomes for patients with peripheral arterial and deep venous pathology.

Intravascular Ultrasound Use in Peripheral Arterial and Deep Venous Interventions: Multidisciplinary Expert Opinion From SCAI/AVF/AVLS/SIR/SVM/SVS

Percutaneous revascularization is the primary strategy for treating lower extremity venous and arterial disease. Angiography is limited by its ability to accurately size vessels, precisely determine the degree of stenosis and length of lesions, characterize lesion morphology, or correctly diagnose postintervention complications. These limitations are overcome with use of intravascular ultrasound (IVUS). IVUS has demonstrated the ability to improve outcomes following percutaneous coronary intervention, and there is increasing evidence to support its benefits in the setting of peripheral vascular intervention. At this stage in its evolution, there remains a need to standardize the use and approach to peripheral vascular IVUS imaging. This manuscript represents considerations and consensus perspectives that emerged from a roundtable discussion including 15 physicians with expertise in interventional cardiology, interventional radiology, and vascular surgery, representing 6 cardiovascular specialty societies, held on February 3, 2023. The roundtable's aims were to assess the current state of lower extremity revascularization, identify knowledge gaps and need for evidence, and determine how IVUS can improve care and outcomes for patients with peripheral arterial and deep venous pathology.

Noninvasive and invasive imaging of lower-extremity acute and chronic venous thrombotic disease

The spectrum of venous thromboembolic (VTE) disease encompasses both acute deep venous thrombosis (DVT) and chronic postthrombotic changes (CPC). A large percentage of acute DVT patients experience recurrent VTE despite adequate anticoagulation, and may progress to CPC. Further, the role of iliocaval venous obstruction (ICVO) in lower-extremity VTE has been increasingly recognized in recent years. Imaging continues to play an important role in both acute and chronic venous disease. Venous duplex ultrasound remains the gold standard for diagnosing acute VTE. However, imaging of CPC is more complex and may involve computed tomography, magnetic resonance, contrast-enhanced ultrasound, or intravascular ultrasound. In this narrative review, we aim to discuss the full spectrum of venous disease imaging for both acute and chronic venous thrombotic disease.

Novel venous balloon for compliance measurement and stent sizing in a post-thrombotic swine model

Objective: Real-time accurate venous lesion characterization is needed during endovenous interventions for stent deployment. The goal of this study is to validate a novel device for venoplasty sizing and compliance measurements. Methods: A compliance measuring sizing balloon (CMSB) uses real-time electrical conductance measurements based on Ohm's Law to measure the venous size and compliance in conjunction with pressure measurement. The sizing accuracy and repeatability of the CMSB system were performed with phantoms on the bench and in a swine model with an induced post thrombotic (PT) stenosis in the common femoral vein of swine. Results: The accuracy and repeatability of the CMSB system were validated with phantom bench studies of known dimensions in the range of venous diameters. In 9 swine (6 experimental and 3 control animals), the luminal cross-sectional areas (CSA) increased heterogeneously along the PT stenosis when the CMSB system was inflated by stepwise pressures. The PT stenosis showed lower compliance compared to the non-PT vein segments (5 mm2 vs. 10 mm2 and 13 mm2 at a pressure change of 40 cm H2O). Compliance had no statistical difference between venous hypertension (VHT) and Control. Compliance at PT stenosis, however, was significantly smaller than that at Control and VHT (p < 0.05, ANOVA). Conclusion: The CMSB system provides accurate, repeatable, real-time measurements of CSA and compliance for assessment of venous lesions to guide interventions. These findings provide the impetus for future first-in-human studies.

Brazilian guidelines on chronic venous disease of the Brazilian Society of Angiology and Vascular Surgery

The Brazilian Society of Angiology and Vascular Surgery has set up a committee to provide new evidence-based recommendations for patient care associated with chronic venous insufficiency. Topics were divided in five groups: 1. Classification, 2. Diagnosis, 3. Conservative or non-invasive treatment, 4. Invasive treatment and 5. Treatment of small vessels. This last series is closely related to the activities of Brazilian angiologists and vascular surgeons, who are heavily involved in the treatment of small superficial veins. These guidelines are intended to assist in clinical decision-making for attending physicians and health managers. The decision to follow a guideline recommendation should be made by the responsible physician on a case-by-case basis taking into account the patient's specific condition, as well as local resources, regulations, laws, and clinical practice recommendations.

Acute and chronic venous occlusion

This review article provides an overview of acute and chronic venous occlusion, a condition that can cause significant morbidity and mortality if not diagnosed and treated promptly. The article begins with an introduction to the anatomy of the venous system, followed by a discussion of the causes and clinical features of venous occlusion. The diagnostic tools available for the assessment of venous occlusion, including imaging modalities such as ultrasound, CT, and MRI, are then discussed, along with their respective advantages and limitations. The article also covers the treatment options for acute and chronic venous occlusion, including anticoagulant therapy and endovascular interventions. This review aims to provide radiologists with an updated understanding of the pathophysiology, diagnosis, and management of acute and chronic venous occlusion.

Society of Interventional Radiology Position Statement on the Management of Chronic Iliofemoral Venous Obstruction with Endovascular Placement of Metallic Stents

PURPOSE

To state the position of the Society of Interventional Radiology (SIR) on the endovascular management of chronic iliofemoral venous obstruction with metallic stents.

MATERIALS AND METHODS

A multidisciplinary writing group with expertise in treating venous disease was convened by SIR. A comprehensive literature search was conducted to identify studies on the topic of interest. Recommendations were drafted and graded according to the updated SIR evidence grading system. A modified Delphi technique was used to achieve consensus agreement on the recommendation statements.

RESULTS

A total of 41 studies, including randomized trials, systematic reviews and meta-analyses, prospective single-arm studies, and retrospective studies were identified. The expert writing group developed 15 recommendations on the use of endovascular stent placement.

CONCLUSIONS

SIR considers the use of endovascular stent placement for chronic iliofemoral venous obstruction to be likely to help selected patients, but the risks and benefits have not been fully quantified in well-designed randomized studies. SIR recommends urgent completion of such studies. In the meantime, careful patient selection and optimization of conservative therapy are recommended prior to stent placement, with attention to appropriate stent sizing and quality procedural technique. The use of multiplanar venography with intravascular ultrasound is suggested in diagnosing and characterizing obstructive iliac vein lesions and in guiding stent therapy. After stent placement, SIR recommends close patient follow-up to ensure optimal antithrombotic therapy, durable symptom response, and early identification of adverse events.

Ultrasound-guided stenting in the common femoral vein for accurate stent distal landing

Objective/Background

Venous stenting has been reported with excellent clinical results; however, inadequate inflow can increase the risk of stent occlusion. When extending the stent into the common femoral vein (CFV), it is essential to ensure adequate inflow from the femoral vein, deep femoral vein (DFV), and great saphenous vein. Accurate identification of the distal landing zone (DLZ) of the stent is crucial to ensure adequate inflow. The DLZ is usually determined by venography or intravascular ultrasound (IVUS) with reference to bony landmarks. However, the uncertainty can lead to misidentification of the DLZ and inadequate stent placement, resulting in stent occlusion.

Methods

From December 2016 to December 2022, 42 venous stent placements were performed in 40 patients with post-thrombotic iliofemoral vein obstruction and/or stenosis. Three patients had developed early stent occlusion owing to a misidentified DLZ. To improve accuracy in identifying the DLZ during venous stenting, ultrasound-guided placement was performed in the CFV of five patients (four on the left and one on the right) with post-thrombotic changes in the CFV and occlusion of the common iliac vein and external iliac vein. The distal end of the stent was adjusted just above the saphenofemoral junction in two cases and just proximal to the DFV confluence in three cases. Stent placement was verified using both long-axis ultrasound and fluoroscopy.

Results

Ultrasound images of the CFV region provided clear visualization of the stent deployment site and accurate landmark locations, such as the saphenofemoral junction and DFV confluence, allowing for precise adjustments during stent deployment. This technique enabled easier and more definitive identification of other branches of the CFV than previously provided by IVUS and venography. No complications were observed in any of the 42 cases, and long-term patency was achieved at the final follow-up after stenting (average, 10 months; range, 3-14 months).

Conclusions

Ultrasound-guided stenting in the CFV allows for real-time and accurate stent deployment with precise adjustment to the optimal DLZ. Using this technique, combined with venography and IVUS, missed distal lesions and subsequent stent occlusion can be prevented, potentially contributing to better treatment outcomes.

Varicose Veins: Approach, Assessment, and Management to the Patient with Chronic Venous Disease

Varicose veins are tortuous and dilated veins commonly seen in chronic venous disease. This article will review chronic venous disease, including its differential diagnosis, workup, and treatment.

Association between the degree of iliac venous outflow obstruction by intravascular ultrasound and lower limb venous reflux

OBJECTIVE

The present study aims to evaluate the association between the degree of iliac venous outflow obstruction (IVOO) identified by intravascular ultrasound (IVUS) and venous reflux presentation in the lower limbs on duplex ultrasound (DU).

METHODS

Patients with bilateral chronic venous insufficiency, CEAP (clinical-etiology-anatomy-pathophysiology) C3 to C6, and a visual analog scale score for pain >5 underwent DU for reflux evaluation of the deep venous system (reflux ≥1 second); superficial system, great saphenous vein, and small saphenous vein (reflux ≥0.5 second); and perforator system (reflux ≥0.35 second). All patients underwent IVUS in the iliac venous territory. The area of the impaired venous segments was categorized as obstruction <50% (category 1), 50% to 79% (category 2), and ≥80% (category 3). The venous clinical severity score and reflux multisegment score (RMS) were assessed.

RESULTS

A total of 51 patients (n = 102 limbs; age, 50.53 ± 14.5 years; 6 men) were included. The predominant clinical severity CEAP class was C3 in 54 of 102 limbs (52.9%). The mean VCSS was 14.3 ± 6.7. A severe RMS (≥3) was registered in 63.4% of the limbs. Of the 102 limbs, 51 (50%) presented with category 1, 27 (26.5%) with category 2, and 24 (23.5%) with category 3. Previous deep vein thrombosis (DVT) was associated with critical obstruction (odds ratio [OR], 3.65; 95% confidence interval [CI], 1.29-10.38; P = .015). The superficial and perforator venous systems had no association with the degree of IVOO. Deep venous reflux (DVR) had a significant association with significant IVOO (obstruction ≥50%; OR, 6.44; 95% CI, 2.19-18.93; P = .001) and critical IVOO (obstruction ≥80%; OR, 4.57; 95% CI, 1.70-12.27; P = .003) and a significant linear association with the IVOO degree and reflux in the femoral veins (P < .001) and popliteal vein (P = .008). Significant lesions were significantly more likely to develop in the left limb (OR, 5.76; 95% CI, 2.46-13.50; P < .001). After multivariate analysis, DVR remained a predictor for significant and critical obstruction (P < .003 and P < .012, respectively). Left limb and previous DVT remained as predictors for IVOO of ≥50% and ≥80% (P < .001 and P = .043, respectively).

CONCLUSIONS

We found a significant linear association between the degree of IVOO and reflux in the deep venous system on DU. Limbs with DVR, a severe RMS, loss of respiratory variation on DU, and previous DVT were more likely to be affected by IVOO of ≥50%, especially with left leg involvement.

Lessons Learned With Venous Stenting: In-flow, Outflow, and Beyond

Venous stents are being used with increasing frequency, with a multitude of dedicated venous stents now well established or emerging onto the market. This review explores the multifaceted aspects of venous stenting. We discuss the history of venous stents, indications for their use, the imaging required before, during and after stenting, as well as some technical tips and tricks which we have found to be helpful in our own daily practice with a particular focus on iliofemoral venous stenting. Ultimately, this article seeks to enhance the understanding of venous stenting, offering insights into what we feel are best practices, challenges, and prospects for improved patient outcomes.

Utilization of Intravascular Ultrasound in the Management of Venous Disease

As the field of Vascular and Interventional Radiology continues to grow, the variety of pathology treated, the approaches to treating various disease processes, and the vast options of equipment and devices continue to grow as well. Numerous venous disease processes have now become commonplace within the treatment realm of interventional radiologists and knowing how to approach each disease process is critical to successful management of these complex patients. A few of the most encountered venous disease processes include pelvic venous disorders, vena cava tumor involvement, venous thrombosis, and inferior vena cava filter placement; an understanding of the management of these processes is integral to the practice of today's interventional radiologists. Intravascular ultrasound (IVUS) has become increasingly important both in the diagnosis and in guiding treatment for venous disease. This article will describe in detail the multiple ways that IVUS can be used in the treatment of complex venous disorders.

Intravascular Ultrasound Versus Computed Tomography Angiography in Sizing and Operative Management of Endovascular Aortic Aneurysm Repair

OBJECTIVES

An abdominal aortic aneurysm (AAA) is a potentially life-threatening condition, the management of which has dramatically evolved over the past 2 decades with an increasing tendency toward endovascular repair (EVAR) rather than open surgical repair. Classically, contrast-enhanced multislice computed tomography (CT) angiography (CTA) is performed preoperatively for procedure sizing and EVAR planning. This entails voluminous contrast injection with risk of allergic reaction, nephropathy, and radiation exposure. Intra-vascular ultrasound (IVUS) has been increasingly used to guide EVAR procedures intraoperatively. The aim of this study is to investigate the accuracy of IVUS in sizing AAAs, device selection, and EVAR planning compared to the gold standard CTA.

DESIGN

This is a prospective observational study enrolling 10 patients who underwent standard infrarenal EVAR procedures performed for unruptured infrarenal AAAs over the course of 1 year. All patients had a preoperative CTA done upon which aneurysm sizing and device planning were performed, and the measurements obtained were compared to those obtained from intraoperative IVUS.

METHODS

All participating patients had unruptured infrarenal AAA, had no renal impairment, and had anatomical suitability for EVAR according to the instructions for use (IFU) of the device manufacturer. Primary endpoint was comparing anatomical measurements recorded by IVUS with those obtained from the preoperative CTA.

RESULTS

Mean age was 65.6 (±6.19), all patients were males and hypertensives and 4 (40%) had a positive family history for AAA. On comparing mean measurements taken by CTA and IVUS, there was no statistically significant differences with exception of maximal aortic diameter and aortic diameter at site of bifurcation (both p-values <.001). There were no statistically significant differences in length measurements between the 2 imaging modalities. Computed tomography angiography was more associated with neck thrombus detection, and IVUS was more associated with calcification detection.

CONCLUSION

Although CT angiography is still the gold standard imaging modality for AAA, IVUS use is very beneficial in EVAR sizing and planning, in addition to intra-operative guidance of the procedure, saving the patient significant time, contrast administration, and radiation exposure, especially in patients with renal impairment and contrast allergy.

CLINICAL IMPACT

A preoperative CT angiogram is the gold standard required investigation for planning and sizing EVARs, with subsequent contrast injection entailing a risk of contrast induced nephropathy and allergic reactions. IVUS has been used as an adjuvant technique to guide EVAR stent graft deployment. However, our study concluded that it can also be reliably used in sizing and planning of the EVAR stent graft along with complementary non contrast imaging, especially in patients with high risk for contrast induced nephropathy and contrast allergy.

Deep venous stenting in females

Deep venous stenting has gained increasing prominence in recent years. This issue focuses on special considerations in female patients. The specific challenge relates to the fact that these patients are often much younger than those in whom arterial stents are placed. The stents have to perform adequately over potentially 60 years- and there is no data of that length available.

An Overview of Specific Considerations in Chronic Venous Disease and Iliofemoral Venous Stenting

Unlike arterial disease, chronic venous disease (CVD) is rarely life-threatening or limb-threatening. However, it can impose substantial morbidity on patients by influencing their lifestyle and quality of life (QoL). The aim of this nonsystematic narrative review is to provide an overview of the most recent information on the management of CVD and specifically, iliofemoral venous stenting in the context of personalized considerations for specific patient populations. The philosophy of treating CVD and phases of endovenous iliac stenting are also described in this review. Additionally, the use of intravascular ultrasound is described as the preferred operative diagnostic procedural tool for iliofemoral venous stent placement.

Society of Interventional Radiology Position Statement on the Endovascular Management of Acute Iliofemoral Deep Vein Thrombosis

PURPOSE

To establish the updated position of the Society of Interventional Radiology (SIR) on the endovascular management of acute iliofemoral deep vein thrombosis (DVT).

MATERIALS AND METHODS

A multidisciplinary writing group with expertise in treating venous diseases was convened by SIR. A comprehensive literature search was conducted to identify studies on the topic of interest. Recommendations were drafted and graded according to the updated SIR evidence grading system. A modified Delphi technique was used to achieve consensus agreement on the recommendation statements.

RESULTS

A total of 84 studies, including randomized trials, systematic reviews and meta-analyses, prospective single-arm studies, and retrospective studies were identified and included in the review. The expert writing group developed 17 recommendations that pertain to the care of patients with acute iliofemoral DVT with the use of endovascular venous interventions.

CONCLUSIONS

SIR considers endovascular thrombus removal to be an acceptable treatment option in selected patients with acute iliofemoral DVT. Careful individualized risk assessment, high-quality general DVT care, and close monitoring during and after procedures should be provided.

Technique of stent sizing in patients with symptomatic chronic iliofemoral venous obstruction-the case for intravascular ultrasound-determined inflow channel luminal area-based stenting and associated long-term outcomes

OBJECTIVE

Femoroiliocaval stenting has become the standard of care for patients with quality-of-life impairing chronic iliofemoral venous obstruction not responding to conservative measures. Although improvement after stenting has been noted in multiple large studies, sizing of stents has been subjective in nature with a general tendency to use smaller stents that would be required to relieve venous hypertension. This study evaluates the authors' technique of using the intravascular ultrasound (IVUS) inflow channel luminal area to guide stent sizing.

METHODS

Patients who underwent femoroiliocaval stenting for quality-of-life impairing chronic iliofemoral venous obstruction and had failed conservative therapy from 2015 to 2021 were included in the study. Clinical outcomes including venous clinical severity score (VCSS), visual analog scale (VAS) pain score, and grade of swelling (GOS) were appraised before and after stenting. Also evaluated were quality of life (Chronic Venous Insufficiency Questionnaire-20 [CIVIQ-20] instrument) and stent outcomes including patencies and reinterventions. Comparisons were made between limbs that underwent placement of larger caliber stents (largest stent diameter >20 mm: >20 mm stent group) vs smaller caliber stents (largest stent diameter ≤20 mm: ≤20 mm stent group). t tests and analysis of variance were used to compare outcomes, whereas the Kaplan-Meier analysis was used to evaluate patencies with log rank used to compare the curves.

RESULTS

A total of 300 patients (300 limbs) underwent stenting with a median age of 58 years. There was a preponderance of men (159 of 300), left laterality (176 of 300), and post-thrombotic syndrome (176 of 300). The median body mass index was 41. There were 120 limbs in the >20 mm stent group and 180 limbs in the ≤20 mm stent group. The median follow-up was 23 months. There was no significant difference in baseline VCSS, VAS pain score, or GOS between the two groups. However, there was a significant difference in IVUS-determined inflow channel luminal area between the two groups (228 mm² >20 mm stent group vs 176 mm² for ≤20 mm stent group [P < .0001]). After stenting there was a significant improvement in the VCSS, VAS pain score, and GOS at 6 weeks, 3, 6, 12, and 24 months (P < .0001) without any difference between the groups (P > .05). The CIVIQ-20 score also improved from 58 to 38 (P < .0001) for the entire cohort and for the two groups (P < .0001). Overall primary, primary-assisted, and secondary patencies at 60 months were 84%, 100%, and 100%, respectively. Reintervention rate was 10% without any difference between the groups.

CONCLUSIONS

Stent sizing using IVUS-determined inflow channel luminal area in patients undergoing stenting for quality-of-life impairing chronic iliofemoral venous obstruction resulted in a significant improvement in the VCSS, VAS pain score, GOS, and quality of life (CIVIQ-20) after stenting. Excellent stent patencies and low reintervention rates were also noted. IVUS-determined inflow channel luminal area represents an objective technique of stent sizing in comparison to the subjective techniques that currently exist.

Iliac vein stent failure in community practice and results of corrective reinterventions

OBJECTIVE

The goal of endovenous stenting is to relieve venous obstruction and reduce peripheral venous hypertension by using large caliber venous stents in the presence of adequate venous inflow and outflow for the stented conduit. The aim of this report is to describe the technical reasons and outcomes for reinterventions in a subset of patients who had a history of iliac vein stenting and were now referred to us at a specialty venous clinic for further care.

METHODS

From January 2016 to December 2021, records of all patients who were referred to us with a history of iliac vein stenting performed at an outside facility and who had a reoperation performed at our center were retrospectively analyzed.

RESULTS

A total of 149 limbs underwent a deep venous reintervention after a failure of a trial of conservative therapy. The mean age of the sample was 57 ± 16 years. The ratio of non-thrombotic iliac vein lesions to post-thrombotic lesions was 1:2.5. The majority of the patients (84%) were CEAP class C4 or higher. The most common reason for reintervention was stent occlusion (74%), followed by iatrogenic stenosis (53%) and in-stent restenosis/shelving (38%). There was a trend for improvement in all clinical parameters (venous clinical severity score, visual analog scale for pain, and edema grade) after the reintervention. Poor inflow was present in 70% of limbs with stent occlusion. The median diameters of stented common femoral vein, external iliac vein, and common iliac vein prior to reintervention were 12, 12, and 13 mm, respectively. The median diameters of stented common femoral vein, external iliac vein, and common iliac vein after reintervention were 14, 15, and 16 mm, respectively. Eighty-eight percent of limbs required at least one further reintervention after initial reoperation.

CONCLUSIONS

Venous reoperations are generally infrequent and required in a small number of patients. Poor inflow appeared to be a common cause of stent occlusion. Iatrogenic stenosis is another common reason for venous reoperation and is difficult to fully rectify through current endovascular techniques and tools. Use of intravascular ultrasound planimetry routinely in every deep venous intervention and thorough knowledge of the principles of venous stenting outlined in this report may help forestall the need for reoperative deep venous surgery in some cases.

Case report: Non-thrombotic iliac vein lesion: an unusual cause of unilateral leg swelling in a patient with endometrial carcinoma

81-year-old female presented with subacute right lower extremity edema due to iliac vein compression by a markedly enlarged external iliac lymph node later identified as newly relapsed metastatic endometrial carcinoma. The patient underwent a full evaluation of the iliac vein lesion and cancer and had an intravenous stent placed with complete resolution of symptoms post-procedure.

Utilization of and Outcomes Associated with Intravascular Ultrasound during Deep Venous Stent Placement among Medicare Beneficiaries

PURPOSE

To evaluate temporal trends, practice variation, and associated outcomes with the use of intravascular ultrasound (US) during deep venous stent placement among Medicare beneficiaries.

MATERIALS AND METHODS

All lower extremity deep venous stent placement procedures performed between January 1, 2017, and December 31, 2019 among Medicare beneficiaries were included. Temporal trends in intravascular US use were stratified by procedural setting and physician specialty. The primary outcome was a composite of 12-month all-cause mortality, all-cause hospitalization, or repeat target vessel intervention. The secondary outcome was a composite of 12-month stent thrombosis, embolization, or restenosis.

RESULTS

Among the 20,984 deep venous interventions performed during the study period, 15,184 (72.4%) utilized intravascular US. Moderate growth in intravascular US use was observed during the study period in all clinical settings. There was a variation in the use of intravascular US among all operators (median, 77.3% of cases; interquartile range, 20.0%-99.2%). In weighted analyses, intravascular US use during deep venous stent placement was associated with a lower risk of both the primary (adjusted hazard ratio, 0.72; 95% confidence interval [CI], 0.69-0.76; P < .001) and secondary (adjusted hazard ratio, 0.32; 95% CI, 0.27-0.39; P < .001) composite end points.

CONCLUSIONS

Intravascular US is frequently used during deep venous stent placement among Medicare beneficiaries, with further increase in use from 2017 to 2019. The utilization of intravascular US as part of a procedural strategy was associated with a lower cumulative incidence of adverse outcomes after the procedure, including venous stent thrombosis and embolization.

Medium Term Outcomes of Deep Venous Stenting in the Management of Venous Thoracic Outlet Syndrome

OBJECTIVE

Venous thoracic outlet syndrome (vTOS) is a relatively rare condition associated with significant morbidity. Its management continues to evolve, with increasing use of endovascular adjuncts, such as percutaneous thrombectomy and angioplasty, in addition to first rib resection. The utility of stenting residual venous stenotic lesions is poorly defined within the literature. This study sought to review the medium term patency rates of upper limb deep venous stenting in the management of vTOS.

METHODS

A single centre, retrospective review of patients managed for vTOS with first rib resection followed by upper limb deep venous stenting between January 2012 and February 2021 was conducted. Post-procedural ultrasounds were reviewed to determine stent patency.

RESULTS

Twenty-six patients were included, with 33 stents placed. The median duration of follow up was 50 months. On venous duplex ultrasound at three years post-operatively, primary patency rates were 66%, primary assisted patency rates were 88%, secondary patency rates were 91%, and total occlusion rates were 9%. After stent placement, 80% of patients remained asymptomatic with regard to compression symptoms.

CONCLUSION

Upper limb deep venous stenting is an effective adjunct to surgical decompression in the management of vTOS. Stent medium term patency rates are promising; however, further studies with longer follow up and larger cohorts with multicentre results are required to confirm these early findings.

Intravascular ultrasound evaluation during iliofemoral venous stenting is associated with improved midterm patency outcomes

OBJECTIVE

Intravascular ultrasound (IVUS) examination is increasingly used in the treatment of iliofemoral venous disease and provides more sensitive and specific detection of stenotic lesions when compared with traditional multiplanar venography alone. Correlations with deep venous stent patency, however, have not yet been investigated. The objective of the study was to evaluate the impact of the use of IVUS examination in addition to multiplanar venography on iliofemoral venous patency.

METHODS

Consecutive patients who underwent stenting for symptomatic thrombotic or nonthrombotic iliofemoral venous lesions (NIVLs) between 2014 and 2020 at a single institution were identified and divided into two groups based on whether IVUS examination was used before stent deployment in addition to multiplanar venography compared with venography alone. A retrospective review of demographic, operative, and follow-up data was performed. Thirty-day and 2-year stent patency were measured as primary end points. χ² analysis, logistic regression models, and Kaplan-Meier survival analysis were used to determine outcomes. Technical details and outcomes were additionally examined among patients treated for acute deep venous thrombosis, post-thrombotic syndrome, or NIVLs separately on subgroup analysis.

RESULTS

We identified 150 patients (173 limbs, 23 bilateral) who underwent iliofemoral stenting during the study period at our institution (mean age: 48.8 ± 16.8 years, 61% female). Adjunctive IVUS utilization before stent deployment was reported in 69 of 173 (39.9%) treated limbs. IVUS examination was more likely to be used in patients who underwent stenting for NIVLs compared with thrombotic disease (41.0% vs 11.2%, P < .01). There was no difference in the number of stents deployed between IVUS and non-IVUS cohorts. However, IVUS examination was associated with the increased total length of the stent deployed (126 ± 56 vs 112 ± 48 mm, P = .04) and a higher rate of infrainguinal stent extension (17.4% vs 6.7%, P = .03). In addition, mean stent diameter was significantly higher when IVUS examination was performed before stent placement (16.3 ± 3.7 vs 15.2 ± 1.9 mm, P < .01). Both 30-day (98.5% vs 89.4%, P = .02) and 2-year (90.3% vs 78.7%, P = .03) primary patency were significantly higher in the IVUS cohort. Adjunctive IVUS use was found to significantly protect against stent reintervention at 2 years on adjusted Cox regression analysis (hazard ratio: 0.22, 95% confidence interval: 0.07-0.71, P = .01).

CONCLUSIONS

Adjunctive IVUS utilization is associated with differences in stent diameter and length selections as well as landing segments in the treatment of thrombotic and nonthrombotic iliofemoral venous disease. IVUS examination before stent deployment significantly protects against 30-day and 2-year stent reintervention when compared with the use of multiplanar venography alone. These data provide stronger evidence for routine IVUS use in addition to venography before iliofemoral venous stenting.

External iliac vein dimensions may change after placement of a more proximal iliac vein stent

OBJECTIVE

We have occasionally observed during vein stenting for proximal iliac vein stenosis, the appearance of a more distal stenosis in the iliac vein that had not been initially observed before placement of the more proximal vein stent. In the present retrospective study, we aimed to document this observation.

METHODS

We identified patients in whom changes in the area measurement and linear dimensions of the external iliac vein (EIV) were observed on venography and/or intravascular ultrasound (IVUS) after stent placement for chronic nonthrombotic iliac stenosis in the common iliac vein (CIV). The images of these IVUS scans were subsequently analyzed to determine the cross-sectional area, major axis, and minor axis measurements in the EIV, before and after placement of a proximal CIV stent.

RESULTS

A total of 32 limbs with complete and quality IVUS and venography images available that allowed for measurement of the EIV before and after vein stent placement in the CIV were evaluated. The patient cohort was 55% men, with a mean age of 63.8 ± 9.9 years and a mean body mass index of 27.8 ± 7.8 kg/m². Of the 32 limbs, 18 were left sided and 14 were right sided. Most (n = 12 [60%]) of the limbs had presented with venous-related skin changes (C4 disease). The remainder of the cohort had had active (C6 disease; n = 4 [20%]) or recently healed (C5 disease; n = 1 [5%]) venous ulceration and isolated venous-related edema (C3; n = 3 [15%]). The minimal CIV area before and after CIV stenting was 28.47 ± 23.53 mm² and 196.34 ± 42.62 mm², respectively. The minimal mean EIV cross-sectional area before and after CIV stenting was 87.44 ± 38.55 mm² and 50.69 ± 24.32 mm², respectively, a statistically significant reduction of 36.75 mm² (P < .001). The mean EIV major axis and minor axis had both decreased similarly. The minimal mean EIV major axis before and after CIV stenting was 15.22 ± 3.13 mm and 11.13 ± 3.58 mm, respectively (P < .001). The minimal mean EIV minor axis before and after CIV stenting was 7.26 ± 2.40 mm and 5.84 ± 1.42 mm, respectively (P < .001).

CONCLUSIONS

The results from the present study have shown that the dimensions of the EIV can change significantly after placement of a proximal CIV stent. Possible explanations include masked stenosis due to distal venous distention resulting from the more proximal stenosis, vascular spasm, and anisotropy. The presence of proximal CIV stenosis can potentially lessen the appearance, or completely mask the presence, of an EIV stenosis. This phenomenon appears unique to venous stenting, and the prevalence is unknown. These findings underscore the importance of completion IVUS and venography after venous stent placement.

Intravascular US: Applications in Interventional Radiology

Interventional radiology applications of intravascular US (IVUS) continue to expand, complementing intraprocedural angiography and providing a unique vantage from which to guide endovascular interventions. Vascular pathologic conditions become sonographically visualized rather than inferred from the planar appearance of the opacified vascular lumen. Perivascular targets become sonographically visualized rather than approximated on the basis of fluoroscopic landmarks. The authors introduce broad categories of IVUS catheters, namely radial and side-firing varieties, as well as prevailing options for each and their technical specifications. Common applications within interventional radiology are covered in a systems approach, including deep venous thrombosis, May-Thurner syndrome, nutcracker syndrome, transjugular intrahepatic portosystemic shunts, aortic interventions, peripheral arterial disease, and endovascular or perivascular biopsy. Discussions are accompanied by technical pearls from the authors, and summarized evidence where IVUS has been shown to reduce procedural time, intravascular contrast agent dose, radiation exposure, and morbidity in each space is presented. Finally, emerging applications and future directions are discussed. ^©RSNA, 2022.

Intravascular ultrasound guidance for lower extremity arterial and venous interventions

This review details the utility of intravascular ultrasound (IVUS) for the management of peripheral artery and venous disease. The purpose of this document is to provide an update in the use of IVUS in peripheral arterial and venous pathology and demonstrate the use of IVUS as a practical diagnostic imaging procedure to evaluate and treat peripheral vascular disorders. IVUS, a diagnostic tool that relies on sound waves to produce precise images of the vessel being evaluated, was originally introduced to the medical community for the purposes of peripheral artery imaging, though it was quickly adapted for coronary interventions with positive outcomes. The utility of IVUS includes vessel measurement, pre- and post-procedural planning, treatment optimisation, and detection of thrombus, dissection or calcium severity. While angiography remains the standard imaging approach during peripheral intervention, multiple observational studies and small prospective trials have shown that in comparison, IVUS provides more accurate imaging detail, which may improve procedural outcomes. IVUS can also address limitations of angiography, including the need to administer contrast medium and eliminate the ambiguity associated with other forms of imaging. This review provides contemporary examples of where IVUS is being used during peripheral intervention as well as representative imaging to serve as a resource for the practising clinician.

Appropriate Use of Intravascular Ultrasound During Arterial and Venous Lower Extremity Interventions

BACKGROUND

There has been growing use of intravascular ultrasound (IVUS) during lower extremity arterial and venous revascularization. Observational data suggest that the use of IVUS can improve periprocedural and long-term outcomes, but largescale prospective data remain limited. Consensus opinion regarding the appropriate use of IVUS during peripheral intervention is needed.

OBJECTIVES

The purpose of this consensus document is to provide guidance on the appropriate use of IVUS in various phases of peripheral arterial and venous interventions.

METHODS

A 12-member writing committee was convened to derive consensus regarding the appropriate clinical scenarios for use of peripheral IVUS. The group iteratively created a 72-question survey representing 12 lower extremity arterial interventional scenarios. Separately, a 40-question survey representing 8 iliofemoral venous interventional scenarios was constructed. Clinical scenarios were categorized by interventional phases: preintervention, intraprocedure, and postintervention optimization. Thirty international vascular experts (15 for each survey) anonymously completed the survey instrument. Results were categorized by appropriateness using the median value and disseminated to the voting panel to reevaluate for any disagreement.

RESULTS

Consensus opinion concluded that IVUS use may be appropriate during the preintervention phase for evaluating the etiology of vessel occlusion and plaque morphology in the iliac and femoropopliteal arteries. IVUS was otherwise rated as appropriate during iliac and femoropopliteal revascularization in most other preintervention scenarios, as well as intraprocedural and postprocedural optimization phases. IVUS was rated appropriate in all interventional phases for the tibial arteries. For iliofemoral venous interventions, IVUS was rated as appropriate in all interventional phases.

CONCLUSIONS

Expert consensus can help define clinical procedural scenarios in which peripheral IVUS may have value during lower extremity arterial and venous intervention while additional prospective data are collected.

Intravascular ultrasound in peripheral venous and arterial interventions: A contemporary systematic review and grading of the quality of evidence

Although angiography has been the primary imaging modality used in peripheral vascular intervention, this technique has major limitations due to the evaluation of three-dimensional vessels in two dimensions. Intravascular ultrasound (IVUS) is an important adjunctive tool that can address some of these limitations. This systematic review assesses the appropriateness of IVUS as an imaging modality for guiding peripheral intervention through evidence collection and clinical appraisal of studies. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a cohort of 48 studies (29 arterial; 19 venous) detailing IVUS use in peripheral vascular intervention were extracted. Qualitative assessment of the studies evaluated pre- and postprocedure efficacy of IVUS and revealed that IVUS-guided peripheral intervention in arterial and venous diagnosis and treatment was superior to other imaging techniques alone. Each study in the cohort was further assessed for reliability and validity using the Oxford Centre for Evidence Based Medicine (CEBM) level of evidence scale. The majority of both arterial (79.3%) and venous (73.7%) studies received a 2b rating, the second highest level of evidence rating. The evidence to date indicates that IVUS results in better clinical outcomes overall and should be more widely adopted as an adjunctive imaging modality during peripheral intervention. (PROSPERO Registration No.: CRD42021232353).

Diagnostic Value of the Iliac Vein Stenosis Percentage Combined With Indicators of Venous Reflux for Iliac Vein Compression Syndrome With Computed Tomography Venography

OBJECTIVES

To identify a cutoff value of iliac vein stenosis in computed tomography venography (CTV) for assisting in the diagnosis of iliac vein compression syndrome (IVCS). Meanwhile, determining whether the inclusion of venous return and collateral imaging findings could further enhance the diagnostic performance.

METHODS

We conducted a retrospective study on 264 patients suspected of IVCS who underwent both CTV and digital subtraction venography (DSV) from January 2016 to December 2020; they were assigned to either a control group (n = 101) or an IVCS group (n = 163) based on the DSV results. The narrowest anteroposterior diameter of the common iliac vein and the anteroposterior diameter of the distal end were measured to calculate the percentage of iliac vein stenosis. Receiver operating characteristic curve analysis was performed to determine the predictive accuracy of the percentage of iliac vein stenosis for IVCS and whether the inclusion of venous reflux indicators can further improve the diagnostic accuracy.

RESULTS

With respect to the DSV results, the area under the curve was 0.797 (P < 0.001). The best cutoff value was 46.67%, corresponding to a sensitivity of 83.44% and a specificity of 69.31% for predicting IVCS. Moreover, the combination diagnostic method had higher sensitivity and accuracy (94.48% vs 83.44% [P = 0.01] and 84.85% vs 78.03% [P = 0.04], respectively).

CONCLUSIONS

The best cutoff percentage of iliac vein stenosis to diagnose IVCS was 46.67% with CTV. The sensitivity and accuracy of the combined diagnostic method were higher than those of the iliac vein stenosis ratio diagnostic method.

Comparison of intravascular ultrasound and magnetic resonance venography in the diagnosis of chronic iliac venous disease

BACKGROUND

The diagnosis of chronic iliofemoral venous obstruction (CIVO) can be made with several different modalities. Intravascular ultrasound (IVUS) is the gold standard in the diagnosis of CIVO. However, being invasive, it should not be the initial examination to screen patients with CIVO. The aim of this report is to compare the performance of magnetic resonance venography (MRV) to IVUS in the diagnosis of CIVO.

METHODS

From January, 2016 to December, 2020, records of all patients who underwent pre-operative MRV and then IVUS in the evaluation of CIVO were retrospectively analyzed.

RESULTS

505 patients were evaluated by any modality for CIVO. 15% (78) of these patients were evaluated by MRV. Patients who had failed a trial of conservative therapy for at least 3 - 6 months and who had disabling and life-style limiting symptoms of CIVO were selected to undergo further evaluation with MRV at the treating physician's discretion. For inclusion in analysis, technically satisfactory IVUS and MRV data was mandatory. Data was available for 60 common iliac vein (CIV) segments and 61 external iliac vein (EIV) segments for comparative analysis after appropriate exclusions. The mean age of the patients was 56 ± 15 years. Male to female ratio was 1:2. The distribution of patients across different CEAP classes was as follows: CEAP 3: 28%, CEAP 4: 62%, CEAP 5: 2% and CEAP 6: 8%. Bland-Altman plots of mean difference in area between IVUS and MRI were 74.1% for CIV and 56.9% for EIV. The sensitivity of MRV was 93% and 100% while the specificity was 0 and 50% for CIV and EIV respectively. The positive predictive value was 93% and 86% while the negative predictive value was 0 and 50% for CIV and EIV respectively. Improvement was noted in clinical parameters (Venous Clinical Severity score; VCSS, visual analogue pain scale and grade of swelling) after IVUS and stenting following MRV investigation. For VCSS, the score improved from 6 ± 2.7 (pre-procedure) to 4 ± 2.7 (post-procedure), p=0.0001.

CONCLUSION

There is dimensional disparity between MRV and IVUS in the diagnosis of symptomatic CIVO. MRV has a high sensitivity but low specificity when compared to IVUS and overestimates the severity of the stenosis in both the EIV and CIV. MRV is not a reliable diagnostic tool for iliac vein stenosis and should not be used for the definitive disposition of CIVO patients.

Intravascular ultrasound for endovascular precision in pediatrics

Intravascular ultrasound (IVUS) is used as a diagnostic adjunct to angiography and has become a valuable diagnostic and interventional tool with a well-documented safety profile. The American College of Cardiology and the European Society of Cardiology have published guidelines regarding the use of IVUS in the setting of percutaneous coronary intervention. IVUS has gained popularity in the interventional radiology (IR) community in recent years; however, there are no consensus guidelines for utilization. Furthermore, IVUS remains an infrequently used modality in pediatric IR, likely because of unfamiliarity with the equipment and techniques, as well as concerns over the compatibility of these instruments with pediatric anatomy. IVUS can be safely used as a helpful and sometimes necessary tool for pediatric interventions in appropriately selected patients. The utility of IVUS for reducing both fluoroscopy time and contrast agent volume makes it particularly valuable in pediatric practice. This article presents an overview of both the rotational and phased-array IVUS types and an in-depth discussion on the most common applications of these techniques in the pediatric setting across multiple procedure categories.

Biomechanical behaviour of PEDOT:PSS-based hydrogels as an electrode for stent integrated enzyme biofuel cells

The possibility of creating a biofuel cell based on a metal stent was shown in this study. Given the existing stent implantation approaches, the integration of a biofuel cell into a stent naturally entails capacity for biofuel cells to be installed into a human body. As a counter electrode, a hydrogel based on iota-carrageenan, polyvinyl alcohol, and PEDOT:PSS, with an immobilized glucose oxidase enzyme, was proposed. Tension tests demonstrated that the hydrogel mechanical behavior resembles that of a bovine's vein. To obtain an analytical description, the deformation curves were fitted using Gent and Ogden models, prompting the fitting parameters which can be useful in further investigations. During cyclic biaxial studies the samples strength was shown to decreases insignificantly in the first 50 cycles and, further, remains stable up to more than 100 cycles. The biofuel cell was designed with the PEDOT:PSS based material as an anode and a Co–Cr self-expanding stent as a cathode. The maximum biofuel cell power density with a glucose concentration of 5 mM was 7.87 × 10⁻⁵ W in phosphate buffer and 3.98 × 10⁻⁵ W in blood mimicking buffer. Thus, the biofuel cell integration in the self-expanding stent was demonstrated.

Current Status and Prospect of Stent Placement for May-Thurner Syndrome

Stent implantation has been proven to be safe and has become the first-line intervention for May-Thurner syndrome (MTS), with satisfactory mid-term patency rates and clinical outcomes. Recent research has demonstrated that catheter-directed thrombolysis is the preferred strategy when MTS is combined with deep vein thrombosis after self-expanding stent placement. However, the stent used for the venous system was developed based on the experience obtained in the treatment of arterial disease. Consequently, relatively common corresponding complications may come along later, which include stent displacement, deformation, and obstruction. Different measures such as adopting a stent with a larger diameter, improving stent flexibility, and increasing stent strength have been employed in order to prevent these complications. The ideal venous stent is presently being evaluated and will be introduced in detail in this review.

[Innovations in the endovascular treatment of peripheral arterial disease]

The cooperation of physicians, engineers and other sciences results in a steady launching of effective tools for vascular treatment, which further support the dominating position of endovascular therapy in the field of PAD. Parallel to the treatment options, non-radiation based image guidance is another area, where innovation helps to reduce radiation burden for patient and staff members without losing procedural quality and despite a growing number of radiation based procedures. Meanwhile, the available portfolio of endovascular tools allows to treat every vessel segment with results comparable to or even better then open surgery. This survey presents new techniques, tools and recently published results from related trials, which will probably have further influence on PAD treatment in the coming years.

Interventionelle Therapie der akuten iliofemoralen Thrombose

Der Goldstandard in der Behandlung der Phlebothrombose ist die konservative Therapie mittels Antikoagulation und Kompression. Bei akuten proximalen iliofemoralen Thrombosen mit Beteiligung der Beckenvene muss jedoch hierbei mit einer Inzidenz für das Entstehen eines postthrombotischen Syndroms im Langzeitverlauf von bis zu 70 % gerechnet werden. Zur Prävention eines solchen Folgeschadens rückt neben der selten durchgeführten operativen venösen Thrombektomie in den letzten Jahren zunehmend die interventionelle rekanalisierende Therapie in den Fokus der Behandlungsstrategie. In dieser Übersicht werden die verschiedenen Techniken und aktuellen Entwicklungen dieser Therapie dargestellt und einer kritischen Wertung vor dem Hintergrund der bestehenden Evidenz unterzogen.

Dimensional disparity between duplex and intravascular ultrasound in the assessment of iliac vein stenosis

Minimum iliac vein caliber necessary to maintain normal peripheral venous pressure can be derived by the Poiseuille equation. Duplex was compared to intravascular ultrasound (IVUS) in the assessment of iliac vein stenosis in this single center retrospective study. Parallel IVUS and duplex caliber data for common iliac vein (CIV) and external iliac vein (EIV) in 382 limbs were separately compared. One or both segments were stenotic by IVUS criteria in 213 limbs. Neither segment was stenotic by IVUS in 22 limbs. Bland-Altman analyses and Passing-Bablok linear regressions were used. Duplex calibers were dimensionally smaller than corresponding IVUS images of CIV and EIV segments in Bland-Altman comparison by a mean of 54 mm² and 34 mm², respectively. Passing-Bablok regression suggested the difference was due to a systematic bias and not proportional. Duplex yields a smaller cross-sectional image of CIV and EIV compared to IVUS. Duplex is not a reliable diagnostic test for iliac vein stenosis.

Does ATTRACT change our DVT management practice?

In 2017, the long awaited results of the ATTRACT trial were published in the New England Journal of Medicine leaving the scientific community with disappointment as the study did not show the expected results. Producing not the expected outcome is not uncommon in science - furthermore, it is important to disapprove common beliefs. But has the ATTRACT trial really the power to change our practice? Are the results correct in terms of evidence based on the methods used?

Discriminating Reflux from Non-Reflux Diseases of Superficial Veins in Legs by Novel Non-Contrast MR with QFlow Technique

Objectives: To find an objective diagnostic tool for the superficial veins in legs. Methods: This study included 137 patients who underwent TRANCE-MRI from 2017 to 2020 (IRB: 202001570B0). Among them, 53 with unilateral leg venous diseases underwent a QFlow scan and were classified into the reflux and non-reflux groups according to the status of the great saphenous veins. Results: The QFlow, namely stroke volume (SV), forward flow volume (FFV), mean flux (MF), stroke distance (SD), and mean velocity (MV) measured in the external iliac, femoral, popliteal, and great saphenous vein (GSV). The SV, FFV, SD, MF, SD, and MV in the GSV (morbid/non-morbid limbs) demonstrated a favorable ability to discriminate reflux from non-reflux in the ROC curve. The SD in the GSV and GSV/PV ratio (p = 0.049 and 0.047/cutoff = 86 and 117.1) and the MV in the EIV/FV ratio, GSV, and GSV/PV ratio (p = 0.035, 0.034, and 0.025/cutoff = 100.9, 86.1, and 122.9) exhibited the ability to discriminate between reflux and non-reflux group. The SD, MV, and FFV have better ability to discriminate a reflux from non-reflux group than the SV and MF. Conclusions: QFlow may be used to verify the reflux of superficial veins in the legs. An increasing GSV/PV ratio is a hallmark of reflux of superficial veins in the legs.