Intravascular Imaging Methods for Venous Disorders

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.

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).

Intravascular ultrasonography provides more sensitive detection of subclavian vein stenosis than venography in patients presenting with Paget-Schroetter syndrome

OBJECTIVE

Spontaneous subclavian vein (SCV) thrombosis (Paget-Schroetter syndrome [PSS]) has been attributed to venous compression at the thoracic outlet and traditionally diagnosed using venography. Intravascular ultrasonography (IVUS) allows for a multidimensional view of vascular structures and might be more accurate in revealing venous compression. The goal of the present study was to compare venography and IVUS in patients presenting with PSS to assess the relative accuracy of each modality.

METHODS

Patients presenting for evaluation of PSS from 2013 to 2019 were evaluated for SCV compression using venography and IVUS. Venography and IVUS measurements of stenosis were performed of the index and contralateral limbs in both neutral and stress (arm overhead) positions. The IVUS data included the SCV diameters in the anteroposterior (AP) plane, craniocaudal (CC) plane, and cross-sectional area (CSA). Stenosis was reported as the percentage of reduction from a reference point (lateral margin of the first rib) for the venography and IVUS data.

RESULTS

For the 35 subjects, the average age was 35 years, 57% were women, 20% had presented with a documented pulmonary embolus, and 70% had initially been treated with thrombolysis. Venography demonstrated SCV occlusion in 3 patients (16%) with the index limb in the neutral position and in 18 patients (54%) with the limb in the stress position. The average stenosis in the index limbs was 41.5% (venography), and the average IVUS stenosis was 41.9% (CC), 61.8% (AP), and 74.5% (CSA; P < .05). A subset analysis revealed that in 10 of 35 patients (28%) in whom venography had identified no significant stenosis (average, 10%), IVUS had identified significant stenosis (33.5% CC, 54.3% AP, 68.7% CSA; P < .05).

CONCLUSIONS

IVUS proved more sensitive than venography in detecting significant stenosis leading to SCV thrombosis. A reduction in the CSA was the most sensitive measure of stenosis. IVUS identified significant stenosis in patients in whom venography failed to do so. The greatest utility of IVUS is in the evaluation of patients with PSS in whom venography shows no evident compression.

Venous Compression Syndromes

Venous compression syndromes occur due to extrinsic compression causing complications of venous hypertension or venous thrombosis. This review focuses on 4 venous compression syndromes involving the left common iliac vein, subclavian vein, left renal vein, and popliteal vein. Clinical presentation, diagnostic methods, and management options are reviewed. When properly diagnosed and treated, long-term consequences can be avoided.

Chronic Venous Obstruction: Diagnostic Considerations and Therapeutic Role of Percutaneous Iliac Stenting

Iliac venous outflow obstruction has an important role in the expression of symptomatic chronic venous insufficiency. This anatomic obstruction is frequently overlooked, owing in part to diagnostic difficulty. The combination of venous obstruction and reflux leads to more severe clinical disease. Current diagnostic modalities do not allow an definitive assessment of hemodynamically critical venous obstruction. No single invasive or noninvasive study can accurately detect borderline obstruction of potential hemodynamic significance. A high index of suspicion is critical in the initial recognition of chronic venous obstruction. The diagnosis relies on clinical signs and symptoms and radiologic assessment of morphologic venous outflow obstruction. Treatment strategy should be based on the results of morphologic investigations such as transfemoral phlebography or, preferably, intravascular ultrasonography. Percutaneous iliac venous stenting offers a safe and efficient method to correct pelvic venous obstruction. Percutaneous iliac stenting does not preclude subsequent venous bypass or corrective superficial and deep reflux surgery. This article reviews the etiologic factors and diagnostic modalities of iliac venous obstruction. The therapeutic role of percutaneous iliac stenting in the management of venous obstruction is also discussed.

May-Thurner syndrome and other obstructive iliac vein lesions: meaning, myth, and mystery

Acute and chronic venous disorders of the lower extremities affect millions of people and cause substantial disability. Long ago, surgeons and pathologists identified the presence of 'spur-like' abnormalities of the left common iliac vein; these abnormalities were hypothesized to result from compression and/or irritation from the adjacent crossing right common iliac artery. In the 1990s, physicians, starting to perform catheter-directed thrombolysis to treat extensive deep vein thrombosis (DVT), observed that about 50% of patients had an iliac vein stenosis. Vascular physicians have become aware of the occasional patient with otherwise-unexplained extremity swelling and/or pain but without a DVT history who is subsequently found to have an iliac vein abnormality. These 'lesions' have been hypothesized to elevate ambulatory venous pressures and thereby produce lower-extremity symptoms, increase the risk of initial and recurrent DVT episodes, and increase the risk of treatment failure with medical and endovascular therapies for thrombotic and non-thrombotic venous conditions. As a result, many practitioners now actively seek iliac venous obstructive 'lesions' when evaluating patients with known or suspected venous disease. However, for many patients, it continues to be unclear what degree of obstruction to venous blood flow is being caused by such lesions, how clinically significant they are, how much emphasis should be placed on identifying them, and when they should be treated. This article seeks to improve the knowledge base of vascular practitioners who make clinical decisions about the diagnosis and treatment of obstructive iliac vein lesions.

Intravascular ultrasound in the evaluation and management of cerebral venous disease

BACKGROUND

Intravascular ultrasound (IVUS) is an important diagnostic tool in many interventions, particularly coronary and carotid artery angioplasty and stenting. In contrast, its application in the management of diseases of the cerebral venous system remains an unexplored territory. We report three patients in whom IVUS was used during angiography for the evaluation of venous flow obstruction secondary to venous sinus thrombosis, venous sinus stenosis, and a transverse sinus mass lesion, respectively. In addition, we review current literature to summarize previous experience, focusing on the advantages and limitations of IVUS technology in interventional cardiology, carotid artery disease, and venous disease.

CASE DESCRIPTIONS

In all three cases, IVUS was used without any complications and provided critical information that guided further management of these distinct diseases. IVUS helped diagnose the presence of intraluminal thrombus, severe stenosis, and a mass lesion in the transverse sinuses and also helped assess the response to angioplasty of the stenotic regions.

CONCLUSIONS

IVUS is a promising tool that has potential to improve diagnostic accuracy and to guide the management of several diseases of the cerebral venous system. The cases we describe suggest that IVUS can be successfully used when performing endovascular interventions in patients with obstruction of venous outflow secondary to venous sinus stenosis, thrombosis, or mass lesions.

Transjugular intravascular ultrasound for the evaluation of hepatic vasculature and parenchyma in patients with chronic liver disease

Background

The evaluation of the hepatic parenchyma in patients with chronic liver disease is important to assess the extension, localization and relationship with adjacent anatomical structures of possible lesions. This is usually performed with conventional abdominal ultrasound, CT-scan or magnetic resonance imaging. In this context, the feasibility and the safety of intravascular ultrasound in the liver have not been assessed yet.

Methods

We tested the safety and performance of an intracardiac echography (ICE) catheter applied by a transjugular approach into the hepatic veins in patients with chronic liver disease undergoing hepatic hemodynamic measurements.

Results

Five patients were enrolled in this pilot study. The insertion of the ICE catheter was possible into the right and middle, but not into the left hepatic vein. The position of the ICE was followed using fluoroscopy and external conventional ultrasound. Accurate imaging of focal hepatic parenchymal lesions, Doppler ultrasound of surrounding blood vessels and assessment of liver surface and ascites were achieved without complications.

Conclusions

This study demonstrated that a diagnostic approach using an ICE device inserted in the hepatic veins is feasible, safe and well tolerated. However, it remains for the moment only an experimental investigative tool. Whether ICE adds further information regarding parenchymal lesions and associated vascular alterations as compared to other techniques, needs additional investigation.

Chronic deep venous obstruction: definition, prevalence, diagnosis, management

Ilio-caval venous obstruction has an important role in the expression of symptomatic chronic venous disease regardless of aetiology. The presence of obstruction has been more or less previously ignored and emphasis placed on reflux alone. Stenting of the ilio-femoral veins guided by intravascular ultrasound (IVUS) can now be performed with low morbidity and mortality using appropriate technique. Current diagnostic modalities do not allow a definitive assessment of haemodynamically critical venous obstruction, which hampers selection of limbs for treatment. The diagnosis must be based on morphological studies (preferably IVUS) in patient selected with specific history, signs and symptoms. A high index of suspicion and generous use of morphological investigations are critical in the initial recognition of venous outflow obstruction. Stenting of the ilio-femoral vein appears to be durable with a substantial improvement in limb pain and swelling, high rate of ulcer healing, enhanced quality of life and decreased disability. The beneficial clinical outcome occurs regardless of the presence of remaining reflux, adjunct saphenous procedures or aetiology of obstruction.

Mechanisms in Experimental Venous Valve Failure and their Modification by Daflon© 500 mg

OBJECTIVES

To characterize the acute response of the vein wall to venous hypertension and associated altered fluid shear stress and to test the effect of micronized purified flavonoid fraction (MPFF, Daflon 500), on this response.

MATERIAL AND METHODS

A femoral arteriovenous fistula was created in Wistar rats (n=48). A cohort of 24 rats received oral treatment with MPFF (100 mg/kg/day body weight), 24 rats underwent the arteriovenous fistula procedure and received no treatment. At days 1, 7 and 21 the animals (n=8 at each time point) were killed. Experimental parameters measured included limb circumference, blood flow at the sapheno-femoral junction, leukocyte infiltration and gelatinase activity (matrix metalloproteinase, MMP).

RESULTS

The acute rise in venous hypertension was accompanied by limb edema and venous reflux together with an eventual loss of valve leaflets in the saphenous vein. There was an increase in granulocyte and macrophage infiltration into the venous wall and the surrounding tissue, and a lesser increase in T- and B-lymphocyte infiltration. These changes were accompanied by a local increase in the proteolytic enzymes, MMP-2 and MMP-9. Administration of MPFF reduced the edema and lessened the venous reflux produced by the acute arteriovenous fistula. Decreased levels of granulocyte and macrophage infiltration into the valves were also observed compared with untreated animals.

CONCLUSIONS

Venous hypertension caused by an arteriovenous fistula resulted in the development of venous reflux and an inflammatory reaction in venous valves culminating in their destruction. MPFF was able to delay the development of reflux and suppress damage to the valve structures in this rat model of venous hypertension.