Impact of degree of stenosis in May-Thurner syndrome on iliac vein stenting

Surgical anteriorization of the left common iliac vein results in improved venous outflow and quality of life for May-Thurner syndrome

May-Thurner syndrome or left iliac vein compression occurs when the left common iliac vein is compressed by the right common iliac artery, leading to venous outflow obstruction. This obstruction can cause venous hypertension, resulting in lower extremity swelling, discoloration, pelvic congestion, and venous ulcerations. The standard surgical treatment of May-Thurner syndrome is endovascular venous stent placement. In a small, single-center sample, surgical anteriorization of the left common iliac vein was used to treat symptomatic left common iliac vein compression in younger patients, alleviating their symptoms, and can be considered an alternative treatment.

Impact of native iliac vein aspect ratio on initial clinical presentation and outcomes following stenting for symptomatic chronic iliofemoral venous obstruction

OBJECTIVE

Venous stenting has become the first line of treatment for patients with symptomatic chronic iliofemoral venous obstruction (CIVO) in whom conservative therapy has failed. Intravascular ultrasound (IVUS) interrogation with the use of normal minimal luminal diameters or areas has become the standard to confirm the diagnosis and determine the adequacy of stenting. However, the aspect ratio (ratio between the maximal and minimal luminal diameters) has also been put forth as a possible metric for determining stent adequacy. This study explores the utility of the native iliac vein and stent aspect ratios in determining the initial presentation and outcomes after stenting.

METHODS

A retrospective analysis of contemporaneously entered data from patients who underwent stenting for quality of life (QoL)-impairing clinical manifestations of CIVO for whom conservative therapy had failed formed the study cohort. The limbs were grouped into three at the time of intervention using the IVUS-determined native vein aspect ratio: group I, those with a ratio of ≤1.4; group II, those with a ratio of 1.41 to 1.99; and group III, those with a ratio of ≥2. The characteristics appraised initially and after stenting included the venous clinical severity score, grade of swelling (GOS), visual analog scale (VAS) for pain score, and the CIVIQ-20 QoL score. Analysis of variance and paired and unpaired t tests were used for comparison of clinical and QoL variables, and Kaplan-Meier analysis was used to evaluate stent patency, with the log-rank test used to discriminate between different curves.

RESULTS

There were a total of 236 limbs (236 patients). The median age for the entire cohort was 62 years (range, 16-92 years). There were 161 women in the study, and left laterality was more common (137 limbs). Post-thrombotic obstruction was noted in 201 limbs (86%). The median body mass index was 36 kg/m2. There were 54 (23%), 64 (27%), and 118 (50%) limbs in groups I, II, and III, respectively. The median follow-up was 65 months. For the entire cohort, after stenting, the venous clinical severity score improved from 6 to 4 (P < .0001) at 3 months and remained at 4 at 6 months (P < .0001), 12 months (P < .0001), and 24 months (P < .0001). The GOS for the entire cohort improved from 3 to 1 (P < .0001) at 3 months and remained at 1 at 6 months (P < .0001), 12 months (P < .0001), and 24 months (P < .0001). The VAS for pain score for the entire cohort improved from 7 to 0 (P < .0001) at 3 months, increased to 2 (P < .0001) at 6 months, and remained at 2 (P < .0001) at 12 months. At 24 months, the VAS for pain score worsened to 3 (P < .0001). For the entire cohort, the CIVIQ-20 score improved from 62 to 40 (P < .0001). There was no difference in the GOS, VAS for pain score, or CIVIQ-20 score between the groups at baseline or at 6, 12, and 24 months after intervention. At 60 months, the primary stent patency was 89% for group I, 80% for group II, and 75% for group III (P = .85). The primary assisted stent patency was 100% for group I, 98% for group II, and 98% for group III (P = .5). Secondary patency was 100% for groups II and III (P > .5). Reintervention was pursued for QoL-impairing clinical manifestations in 53 limbs (22%) without a significant difference between the three groups (P = .13).

CONCLUSIONS

The native vein aspect ratio does not appear to determine the initial clinical presentation or QoL or impact the clinical or QoL outcomes after stenting for CIVO. Following stenting, no patient had an aspect ratio >2, with 97% of patients having an aspect ratio ≤1.4 and the remaining 3% having an aspect ratio of 1.41 to 1.99. IVUS-determined minimal cross-sectional luminal area and not the aspect ratios should be used for confirmation of the diagnosis of CIVO and to assess the adequacy of stenting.

The beneficial role of complex decongestive therapy in patients with symptomatic chronic iliofemoral venous obstruction with phlebolymphedema

OBJECTIVE

Phlebolymphedema has been noted to be one of the most common causes of lymphedema in the lower extremity in western societies. Although complex decongestive therapy (CDT) represents the mainstay of lymphedema treatment, its role for phlebolymphedema arising from chronic iliofemoral venous obstruction (CIVO) merits further exploration. We evaluated this through the use of a protocol of CDT first for limbs with CEAP (clinical, etiologic, anatomic, pathophysiologic) clinical C3 disease and stent correction of obstruction before CDT for those with more advanced disease (CEAP C4-C6). In the present study, we analyzed the outcomes after the use of such a protocol.

METHODS

We analyzed prospectively collected data for 192 limbs (166 patients) that underwent treatment of quality-of-life (QoL) impairing symptoms from CIVO due to lymphoscintigraphically determined phlebolymphedema between 2017 and 2022. The characteristics evaluated included CEAP clinical class, venous clinical severity score (VCSS), grade of swelling (GOS), visual analog scale (VAS) pain score, QoL (CIVIQ-20 [20-item chronic venous disease quality of life questionnaire]), stenting for CIVO, and outcomes related to CDT and stenting. For the limbs undergoing CDT or stenting followed by CDT, the outcomes were evaluated at 6 weeks and 3, 6, and 12 months after completion of CDT. Paired and unpaired t tests, χ2 tests, and analysis of variance were used for comparisons of clinical variables. Kaplan-Meier analysis was used to evaluate stent patency, with the log-rank test used to discriminate between different curves.

RESULTS

Of the 192 limbs (166 patients) in the entire cohort, 74 were in the C3 group and 118 were in the C4-C6 group. The median patient age was 63 years; 57 were men and 109 were women. In the C3 group, after CDT, improvement had occurred in the VCSS and VAS pain score at 6 weeks (P < .0001) and at 3 (P < .0001), 6 (P < .0001), and 12 (P < .0001) months. Improvement in the GOS was noted at 6 (P < .0001) and 12 (P = .0005) months. The CIVIQ-20 score improved from 63 to 38 (P = .009). Nine limbs (12%) in the C3 group required stenting after CDT. In the C4-C6 group, of the 118 limbs, 75 (64%) underwent stenting only and 43 (36%) underwent stenting followed by CDT for persistent QoL impairing symptoms. For this latter group, after CDT, improvement occurred in the VCSS, GOS, and VAS pain score at 6 weeks (P < .0001) and 3 (P < .0001), 6 (P < .0001), and 12 (P < .0001) months. The CIVIQ-20 score improved from 61 to 34 (P < .0001). The primary, primary assisted, and secondary patency in the C4-C6 group at 36 months was 92%, 100%, and 100%, respectively.

CONCLUSIONS

For CEAP C3 patients with phlebolymphedema due to CIVO, CDT should be a part of the first line of treatment. Stenting should be reserved for those with QoL impairing symptoms despite the use of CDT. Additionally, CDT helps provide symptom relief for patients with more advanced CEAP C4-C6 disease with persistent or residual edema after stenting. Further study is warranted.

Endovascular resolution of complete common iliac vein stenosis in a case of May-Thurner syndrome with underlying malignancy

INTRODUCTION AND IMPORTANCE

May-Thurner Syndrome (MTS) is an uncommon etiology of left common iliac vein thrombosis due to arterial compression. In this report, we describe a case of MTS with severe occlusion of the left common iliac vein in the context of a previously undiagnosed pancreatic cancer. We detail the endovascular resolution of the iliac vein compression and show long-term patency.

CASE PRESENTATION

A 33-year-old woman on oral contraceptive pills presented with extensive thrombosis of the left common iliac vein extending cephalad into the lower IVC and inferiorly to the femoral vein. The thrombus was refractory to therapeutic heparin. Mechanical thrombectomy removed the occluding thrombus. Intravenous ultrasound identified severe compression of the left common iliac vein by the right common iliac artery. Angioplasty and stenting provided complete resolution of the lesion. Imaging and hematologic workup revealed a pancreatic malignancy and concomitant hypercoagulable state that likely precipitated the patient's presentation.

CLINICAL DISCUSSION

Endovascular intervention provided complete resolution of severe iliac vein compression. Patency was maintained at 6-month follow-up. Research suggests that the anatomical lesion predisposing individuals to MTS is relatively common despite infrequent occurrence of the syndrome. This case highlights the importance of a high clinical suspicion for associated hypercoagulable states when MTS is discovered.

CONCLUSION

There is limited research exploring the relationship between severity of iliac vein compression and endovascular treatment outcome. This case documents endovascular resolution of a severe lesion with maintained patency.

Inguinal intranodal lymphangiography reveals a high incidence of suprainguinal lymphatic disease in patients with leg edema undergoing stenting for symptomatic chronic iliofemoral venous obstruction

OBJECTIVE

Recent studies have emphasized the important role lymphatics play in the drainage of interstitial fluid and edema prevention. Although the infrainguinal lymphatics have been studied in some depth, with patterns of pathology identified, such data above the groin are sparse, especially for patients with phlebolymphedema. The present study attempts to evaluate the status of lymphatic flow above the inguinal ligament in patients presenting with edema and undergoing stenting for symptomatic chronic iliofemoral venous obstruction (CIVO).

METHODS

A total of 31 lower limbs that underwent pedal lymphoscintigraphy for leg edema and subsequent stenting for symptomatic CIVO formed the study cohort. Each limb underwent intranodal lymphangiography of an ipsilateral inferior inguinal lymph node (10 mL of lipiodol) at the time of stenting. Fluoroscopic visualization of lipiodol transit was performed at 20, 40, and 60 minutes and 3 hours after injection. Enumeration of the lymph nodes and lymphatic collector vessels from above the inguinal ligament to L1, visualization of the thoracic duct, the time delay to visualization of the thoracic duct, and pathologic changes to the thoracic duct when present were all evaluated. These anomalies were independently scored, with the scores combined to generate a total suprainguinal score (range, 0-3). This score was then compared to the limb's lymphoscintigraphically derived infrainguinal score (total infrainguinal score range, 0-3) using the t test and Spearman correlation. The clinical outcomes (grade of swelling, venous clinical severity score) after stenting were appraised.

RESULTS

Of the 30 patients (31 limbs), 18 were women, with left laterality noted in 23 limbs. A nonthrombotic iliac vein lesion occurred in 9 limbs and post-thrombotic syndrome in 22 limbs. Of the 31 limbs, 24 (77%) had suprainguinal lymphatic disease (SLD), with 22 of the 24 limbs having severe SLD and 2, mild SLD. When SLD was compared with infrainguinal lymphatic disease, 6 limbs (19%) had the same degree of involvement above and below the groin (1 with normal and 5 with severe disease), 17 limbs (55%) had more severe SLD, and 8 limbs (26%) had more severe infrainguinal lymphatic disease. Three limbs with normal pedal lymphoscintigraphic findings had severe SLD. The Spearman correlation coefficient for the comparison of SLD and infrainguinal disease in the same limb was 0.1 (P = .69). At baseline, the limbs with severe SLD had the same degree of leg swelling and venous clinical severity score as the limbs with absent to mild SLD (P > .1) with similar improvements after stenting (P > .4). Seven limbs underwent complex decongestive therapy (all with severe SLD and concomitant severe infrainguinal disease in one) to treat significant residual leg edema, with improvement.

CONCLUSIONS

SLD appears to be common in patients with leg edema undergoing stenting for symptomatic CIVO. Such disease appears to affect the thoracic duct more commonly. Although patients with persistent or residual leg edema after stenting can benefit from complex decongestive therapy, further workup in the form of inguinal intranodal lymphangiography and targeted intervention might need to be considered for those who do not benefit from such therapy. Further study is warranted.

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.

The utility of computed tomography venography in the routine evaluation of patients who present to a lymphedema center with lower extremity edema

OBJECTIVE

Computed tomography venography (CTV) is not routinely used to screen patients presenting with a presumed lower extremity lymphedema diagnosis for left iliac vein obstruction (IVO) or May-Thurner syndrome (MTS). The objective of this study is to determine the utility of routine CTV screening for these patients by evaluating the proportion presenting with clinically significant CTV-identified left IVO.

METHODS

We retrospectively reviewed 121 patients who had presented to our lymphedema center with lower extremity edema between November 2020 and May 2022. Information regarding demographics, comorbidities, lymphedema characteristics, and imaging reports was collected. Cases of IVO present on CTV were reviewed by a multidisciplinary team to determine the clinical significance of the CTV findings.

RESULTS

Of the patients with complete imaging studies, 49% (n = 25) had abnormal lymphoscintigraphy findings, 45% (n = 46) had reflux on ultrasound, and 11.4% (n = 9) had IVO on CTV. Seven patients (6%) had CTV findings of IVO and edema of either the isolated left (n = 4) or bilateral (n = 3) lower extremities. Cases of IVO on CTV were determined by the multidisciplinary team to be the predominant cause of lower extremity edema for three of these seven cases (43%; or 2.5% of all 121 patients).

CONCLUSIONS

Six percent of patients presenting to a lymphedema center with lower extremity edema had left-sided IVO on CTV suggestive of MTS. However, the cases of IVO were determined to be clinically significant <50% of the time or for 2.5% of all patients. CTV should be reserved for patients with isolated left-sided or bilateral lower extremity edema with a greater left-sided component and a history of findings that raise clinical suspicion for MTS.

Delphi Consensus on Reporting Standards in Clinical Studies for Endovascular Treatment of Acute Iliofemoral Venous Thrombosis and Chronic Iliofemoral Venous Obstruction

Acute iliofemoral deep vein thrombosis and chronic iliofemoral venous obstruction cause substantial patient harm and are increasingly managed with endovascular venous interventions, including percutaneous mechanical thrombectomy and stent placement. However, studies of these treatment elements have not been designed and reported with sufficient rigor to support confident conclusions about their clinical utility. In this project, the Trustworthy consensus-based statement approach was utilized to develop, via a structured process, consensus-based statements to guide future investigators of venous interventions. Thirty statements were drafted to encompass major topics relevant to venous study description and design, safety outcome assessment, efficacy outcome assessment, and topics specific to evaluating percutaneous venous thrombectomy and stent placement. Using modified Delphi techniques for consensus achievement, a panel of physician experts in vascular disease voted on the statements and succeeded in reaching the predefined threshold of >80% consensus (agreement or strong agreement) on all 30 statements. It is hoped that the guidance from these statements will improve standardization, objectivity, and patient-centered relevance in the reporting of clinical outcomes of endovascular interventions for acute iliofemoral deep venous thrombosis and chronic iliofemoral venous obstruction in clinical studies and thereby enhance venous patient care.

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.

Predictors of long-term outcomes after catheter-directed thrombolysis combined with stent implantation in acute deep vein thrombosis secondary to iliac vein compression

The purpose of this study is to analyze predictive factors for long-term clinical outcomes after catheter-directed thrombolysis (CDT) combined with stent implantation for acute deep vein thrombosis (DVT) secondary to iliac vein compression (IVC). A retrospective analysis was performed to review clinical data and follow-up information on 52 patients who underwent CDT combined with stent implantation for acute DVT secondary to IVC from June 2015 to March 2020. Clinical outcomes including stent patency and incidence of postthrombotic syndrome (PTS) were investigated using Kaplan-Meier analysis. All included patients were categorized into 2 groups according to the presence of PTS. Potential risk factors, including age, gender, degree of iliac vein stenosis, time from onset to treatment, dosage of thrombolytic agent, stent extending below the inguinal ligament, and duration of anticoagulation for PTS were evaluated using multivariate logistic regression analysis. Over a median follow-up of 24 months, 4 individuals underwent reintervention due to in-stent stenosis or stent compression. Primary stent patency was 98.1% at 1 month, 94.2% at 6 months, 90.4% at 12 months, and 88.5% at 24 months. Freedom from PTS was 98.1% at 6 months, 84.6% at 12 months, and 75% at 24 months. No treatment-related mortality or morbidity was observed. Based on the development of PTS, 13 patients with PTS were classified into group A and 39 patients without PTS were regarded as group B. Upon multivariate logistic regression analysis, key prognostic factors for PTS were degree of iliac vein stenosis and time from onset to treatment. CDT combined with stent implantation is safe and effective for acute DVT secondary to IVC in the long-term perspective. Severe iliac vein stenosis and longer period from onset to treatment may be associated with a higher risk of PTS.

Improvement following restoration of inline flow argues against comprehensive thrombus removal strategies and for selective stenting in acute symptomatic iliofemoral venous thrombosis

OBJECTIVE

Randomized trials have demonstrated the benefit of thrombus removal strategies in iliofemoral deep venous thrombosis (IFDVT) in providing early symptom relief and decreasing the incidence of post-thrombotic syndrome (PTS), especially severe PTS. However, the impact of quantum of residual thrombus burden (RTB) on PTS as determined by intravascular ultrasound examination and the role of venous stenting in the acute setting have not been evaluated and represent the focus of this study.

METHODS

Sixty-nine limbs (65 patients) undergoing thrombus removal for acute symptomatic IFDVT between 2015 and 2021 formed the study cohort. The Venous Clinical Severity Score (VCSS) (range, 0-27) grade of swelling (GOS) (range, 0-4), and visual analog scale (VAS) pain scores (range, 0-10) were evaluated initially and at 6, 12, and 24 months after thrombus removal. Quality of life was appraised using the CIVIQ-20 instrument. The extent of initial and RTB after the intervention was estimated using intravascular ultrasound examination. Grading was done as less than 50% (1), 50% to 99% (2), or 100% (3) of luminal thrombus fill within each segment (common femoral vein, external iliac vein, and common iliac vein) by a blinded rater and then combined to generate a total score. The use of stenting, both concurrent (severe residual stenosis/persistent occlusion) and delayed (quality of life impairing residual or recurrent symptoms), was evaluated.

RESULTS

Of the 69 limbs, 53 underwent pharmacomechanical/mechanical thrombectomy (PMT), whereas 16 patients underwent PMT and catheter-directed thrombolysis with restoration of inline flow in all limbs. Post-intervention VCSS improved from 6 to 2 at 24 months (P < .0001). GOS improved from 4 to 0 at 24 months (P < .0001). The VAS pain score went from 5 to 0 at 6 months (P < .0001) and remained at 0 at 12 months (P < .0001), but increased to 3 at 24 months (P = .02). The CIVIQ-20 score improved from 38 to 22 (P = .001) over a median follow-up of 19 months. The median RTB total score improved from 9 to 4 (P < .0001). There was no impact of RTB total score (<3 vs >3) on VCSS (P = NS), GOS (P = NS), VAS pain score (P = NS) or CIVIQ-20 score (P = NS) at the various time points. Concurrent stenting was used in 23 limbs (33%) and delayed stenting was carried out in 10 limbs (14%). The median time to delayed stenting was 4 months after the initial thrombus removal intervention.

CONCLUSIONS

In patients undergoing PMT or PMT with catheter-directed thrombolysis for acute symptomatic IFDVT, the restoration of inline flow seems to be adequate to provide symptom relief and decrease the incidence of PTS. The extent of RTB does not seem to impact the VCSS, GOS, VAS pain score, or quality of life after such restoration. Stenting can be pursued selectively in the acute setting to help restore inline flow.

Comparison between a dedicated venous stent and standard composite Wallstent-Z stent approach to iliofemoral venous stenting: Intermediate-term outcomes

OBJECTIVE

Dedicated venous stents have not been used in the management of symptomatic chronic iliofemoral venous obstruction (CIVO) until recently. The Bard Venovo stent (Becton, Dickinson, and Co, Franklin Lakes, NJ) is one such stent noted to have an increased chronic outward force and radial resistive force compared with the Wallstent (Boston Scientific, Marlborough, MA). In the present study, we evaluated the outcomes following the use of the Bard Venovo stent vs a matched cohort of limbs that had undergone stenting with the Wallstent-Zenith (Z) stent (Cook Medical Inc, Bloomington, IN) composite configuration.

METHODS

A review of contemporaneously entered electronic medical record data for 167 patients (167 limbs) with initial iliofemoral stents placed from 2019 to 2020 for quality of life (QOL)-impairing CIVO that had failed conservative therapy was performed. The visual analog scale for pain score (score, 0-10), grade of swelling (score, 0-4), venous clinical severity score (score, 0-27), and the 20-item chronic venous insufficiency quality of life questionnaire instrument for QOL were evaluated before and after intervention to assess the effects of stenting. A Kaplan-Meier analysis was used to examine primary, primary-assisted and secondary stent patency, and analysis of variance with repeated measures was used to compare clinical outcomes.

RESULTS

A total of 167 limbs had undergone Bard Venovo stenting (56 men and 111 women). Their median age was 61 years. The laterality was right and left in 70 and 97 limbs, respectively. Post-thrombotic syndrome was seen in 84 limbs and nonthrombotic iliac vein lesions/May-Thurner syndrome in 83 limbs. At 6 months, the venous clinical severity score had improved from 7 to 4 in the limbs with a unilateral Venovo (UV) stent and from 5 to 4 in the composite Wallstent-Z stent group (P = .9). The grade of swelling had improved from 3 to 1 in the UV group and from 3 to 1 in the composite group (P = .6), and the visual analog scale for pain score had improved from 7 to 2 in the UV group and from 5 to 0 in the composite group (P = .007). At 12 months, ulcers had healed in 53% (8 of 15) of the UV group and 56% (5 of 9) of the composite group (P = .7). The global 20-item chronic venous insufficiency quality of life questionnaire scores had improved from 58 to 28 in the UV group and from 59 to 40 in the composite group (P = .6). The cumulative primary, primary-assisted, and secondary patency at 18 months was 81%, 97%, and 98% in the UV group and 87%, 98%, and 100% in the composite group, respectively (P > .4). No difference in the reintervention rates was noted between the two groups (P = .5).

CONCLUSIONS

For patients who had undergone stenting for QOL-impairing CIVO, the results with the Bard Venovo venous stent were comparable to those with the composite Wallstent-Z stent configuration for clinical outcomes, QOL improvement, and stent patency. Further study is, however, required to confirm this improvement in the long term.

Management of May Thurner Syndrome in Pregnant Patients

May Thurner Syndrome contributes to thromboembolic disease and can cause significant morbidity in pregnant patients secondary to exaggerated anatomic relationships and physiologic changes in the hematologic system favoring thrombogenesis. Because this condition is both underrecognized and underreported, management in pregnant and postpartum patients is based on expert opinion without any formal evidence-based guidance. Herein, we review five pregnancies in four patients with May Thurner Syndrome and general management strategies. Through collaborative and multidisciplinary care, patients with May Thurner Syndrome can be safely and successfully managed during pregnancy and the postpartum period with appropriate anticoagulation.

Iliofemoral venous configurations from three-dimensional computed tomography venogram and their relevance to stent design

OBJECTIVE

Iliofemoral venous stenting has become the standard of care for patients presenting with quality-of-life impairing symptoms of chronic iliofemoral venous obstruction not responding to conservative measures. This has led to an increased use of venous stenting over the last several years. However, iliofemoral venous anatomy in patients requiring such intervention remains poorly elucidated. This study attempts to fill that gap.

METHODS

Twenty-two consecutive patients with intravascular ultrasound examination-confirmed chronic iliofemoral venous obstruction underwent three-dimensional reconstruction of their computed tomography venogram images. Relevant angles, tortuosity (tort index-ratio between centerline length, and straight line length), lengths, and diameters were computed and analyzed. We used t tests for comparisons between the right and left sides. A P value of .05 or less was considered significant.

RESULTS

Of the angles calculated, the median of the angles between the horizontal and common iliac vein (CIV) was 66° on the right and 60° on the left (P < .01). The median inferior vena cava-CIV angle was 172° on the right and 165° on the left (P < .0001). The CIV-EIV angle was 159° on the right and 151° on the L (P = .01). Overall, the median tortuosity was 1.07 on the right and 1.12 on the left (P = .007). The median centerline length of the CIV was 42mm on the right and 60mm on the left (P < .0001). The median external iliac vein length was 73 mm on the right and 88 mm on the left (P < .0001). The overall median iliac vein length was 220 mm on the right and 237 mm on the left (P < .01). The median diameters of the inferior vena cava at the iliocaval confluence, 20, 40, and 60 mm cranial to the confluence, were 23, 20, 22, and 23 mm, respectively.

CONCLUSIONS

Overall, the left side has steeper angles, greater tortuosity, and longer lengths than the right side. These disparities should be considered during femoroiliocaval stent construction.

Role of lower extremity fasciectomy-fasciotomy in patients with persistent leg pain after stenting for chronic iliofemoral venous obstruction

Although clinical improvement after stenting for symptomatic iliofemoral venous obstruction has been demonstrated in multiple large studies, a small proportion of patients will experience persistent quality of life–impairing symptoms. Swelling in such a setting represents the concomitant presence of lymphedema and will respond to treatment directed at the lymphedema. In contrast, persistent pain likely arises from venous hypertension in the lower leg, leading to the development of chronic compartment syndrome. Evaluation of intracompartmental pressures in such patients can help confirm the diagnosis, and fasciectomy combined with fasciotomy will treat the issue. In the present series, we evaluated six patients (six limbs) who had undergone fasciectomy combined with fasciotomy and their outcomes.

A systematic review of current trends in pharmacologic management after stent placement in nonthrombotic iliac vein lesions

Objective

Stenting of the iliac vein is increasingly recognized as a treatment for chronic venous insufficiency (CVI). However, the pharmacologic management after stent placement is unclear. This review was conducted to illustrate recent trends in anticoagulation and antiplatelet regimens following stent placement for nonthrombotic iliac vein lesions (NIVL).

Methods

The MEDLINE database was searched using the term “iliac vein stent.” Retrieval of articles was limited to studies conducted on humans and published in English between 2010 and 2020. Studies were included that described iliac vein stent placement. Studies were excluded that contained fewer than 25 patients, performed procedures other than stent placement, did not specify the postoperative anticoagulant used, or treated lesions of thrombotic origin.

Results

12 articles were included in this review, yielding a total of 2782 patients with a male-to-female ratio of 0.77. The predominant CEAP classification encountered was C3. The most common stent used in the included studies was the Wallstent (9/12), and the most common pharmacologic regimen was 3 months of clopidogrel (6/12). Warfarin, aspirin, cilostazol, and rivaroxaban were among other agents used. Primary stent patency ranged from 63.1 to 98.3%. There was no apparent correlation between pharmacologic agent used and stent patency or subjective patient outcomes.

Conclusion

Multiple different approaches are being taken to pharmacologically manage patients following stent placement for NIVL. There is no consensus on which agent is best, nor is there a formal algorithmic approach for making this decision. Additionally, the findings in this study call into question whether anticoagulation following stenting for NIVL is necessary at all, given the similar outcomes among the different agents utilized. This review underscores the potential value of undertaking a multi-institutional prospective study to determine what is the best pharmacologic therapy following venous stent placement for NIVL.

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.

Effect of body mass index on initial presentation and outcomes after stenting for quality of life-impairing chronic iliofemoral venous obstruction

OBJECTIVE

The incidence of obesity has been increasing, with recent data indicating that the age-adjusted mean body mass index (BMI) is close to 30 kg/m² in the United States. Prior studies have raised concerns for an increased incidence of chronic venous insufficiency in the obese population. We aimed to build on current knowledge by assessing the effects of BMI on the initial presentation and outcomes after intravascular ultrasound (IVUS) luminal area-guided stenting in patients presenting with quality of life (QOL)-impairing chronic iliofemoral venous obstruction (CIVO).

METHODS

A retrospective analysis of contemporaneously entered electronic medical record data on 464 continuous patients (464 limbs) with initial iliofemoral stents (2014-2017) for QOL-impairing CIVO was performed. The characteristics evaluated and compared included the degree of iliofemoral compression, CEAP (clinical, etiologic, anatomic, pathophysiologic) clinical class, venous clinical severity score (VCSS), grade of swelling (GOS), visual analog scale (VAS) for pain score, ulcer healing, reflux (venous segmental disease score; venous filling index-90), calf pump function (ejection fraction; residual volume fraction), and quality of life (CIVIQ-20 [chronic lower limb venous insufficiency 20-item questionnaire]) for those with a BMI <30 kg/m² (group I) and a BMI ≥30 kg/m² (group II). Paired and unpaired t tests were used for comparisons of the clinical variables and a Kaplan-Meier analysis was used to evaluate stent patency.

RESULTS

Of the 464 limbs in the study cohort, 122 were in group I and 342 in group II. The median BMI was 26.3 kg/m² (interquartile range, 19.6-29.9 kg/m²) in group I and 38.9 kg/m² (interquartile range, 30.0-66.9 kg/m²) in group II. The IVUS luminal area-determined degree of compression was higher in group I than in group II across the common iliac, external iliac, and common femoral segments (P < .01). The supine foot venous and femoral venous pressures were higher in group II than in group I (P < .001). The ejection fraction was higher (57.4% vs 45.6%; P = .0008) and residual volume fraction was lower (27.5% vs 40.5%; P = .0008) in group II than in group I. Although the baseline VCSS and GOS were lower in group I than in group II (P < .05), no differences were found in the VAS for pain scores or ulcer prevalence. The median follow-up was 22 months. At 24 months after stenting, improvement was found in the VCSS, GOS, and VAS for pain score in both groups. The CIVIQ-20 QOL score had improved from 58.1 to 18.8 in group I (P = .0002) and from 60 to 37.5 in group II (P < .0001). At 5 years, primary patency was 70% in group I and 73% in group II (P = .6) and primary assisted patency was 100% in both groups (P = .99) without a significant difference in the reintervention rate (P = .5).

CONCLUSIONS

Obese patients with CIVO-impairing QOL have a lesser degree of iliofemoral venous stenosis, more severe venous hypertension, and better calf pump function than their nonobese counterparts. After stenting, no differences were found in the clinical, stent patency, or QOL-related outcomes between the two groups.

In-stent restenosis and stent compression following stenting for chronic iliofemoral venous obstruction

OBJECTIVE

In-stent restenosis (ISR) and stent compression (SC) are problems encountered after stenting for chronic iliofemoral venous obstruction that are responsible for a majority of reinterventions. However, characteristics of ISR and SC, in addition to outcomes after reintervention, have not been explored in detail and represent the focus of this study.

METHODS

A retrospective analysis of contemporaneously entered electronic medical record data on 578 limbs/patients with initial unilateral iliofemoral venous stents placed from 2014 to 2018 was performed. ISR was estimated from stent and flow channel diameters measured using duplex ultrasound. SC was estimated from rated stent diameter and actual stent diameter on duplex ultrasound. Characteristics evaluated included onset of ISR/SC after stent placement and progression over time. Analysis was performed to evaluate risk factors for the development of ISR and SC. Outcomes after reintervention for ISR/SC were also appraised.

RESULTS

A total of 578 limbs underwent stenting for stenotic lesions (nonthrombotic iliac vein lesion/post-thrombotic syndrome). ISR was noted in 27% of limbs on post-intervention day 1. The prevalence of ISR increased to 74% by 3 months and stabilized thereafter. SC was noted in 80% of limbs on day 1 and plateaued. Of the variables evaluated as potential risk factors for ISR, intravascular ultrasound determined that stent inflow luminal area and shear rate were found to be significant. For SC, asymmetric stent sizing was a significant risk factor. Over a median follow-up of 24 months, 95 of 578 (16.4%) limbs underwent reintervention for ISR, SC, or a combination. The median time to reintervention was 11 months. There was no statistically significant difference in the degree of ISR/SC among patients who underwent reintervention vs those who did not (P > .05). However, there was a statistically significant difference in the grade of swelling (P = .006) and visual analog scale pain scores (P < .0001) between those who underwent reintervention and those who did not. Primary, primary assisted, and secondary patencies at 60 months were 70%, 98%, and 84% after reintervention for ISR and 70%, 99%, and 84% for SC, respectively.

CONCLUSIONS

Although ISR and SC are both common after stenting for chronic iliofemoral venous obstruction, neither are relentlessly progressive. Indication for reintervention must be a recurrence of symptoms with impairment of quality of life and not the percentage of ISR or degree of SC. After reintervention good outcomes can be expected both in terms of clinical improvement and stent patency. Further study of the impact of shear rate on stent flow is required to help reduce the incidence of ISR.

Utility of the 50% stenosis criterion for patients undergoing stenting for chronic iliofemoral venous obstruction

OBJECTIVE

The criterion for venous stenting in symptomatic chronic iliofemoral venous obstruction has been the arbitrary use of stenosis of ≥50%. In the present study, we evaluated the intravascular ultrasound (IVUS)-determined degree of stenosis in patients who had undergone stenting for quality of life (QOL)-impairing symptoms and assessed the utility of the 50% stenosis cutoff.

METHODS

A retrospective review of contemporaneously entered electronic medical record data from 480 continuous patients (480 limbs) with initial iliofemoral stents placed (2014 to 2017) for symptomatic chronic iliofemoral venous obstruction impairing their QOL was performed. The IVUS-determined normal minimal luminal areas for the common femoral vein (125 mm), external iliac vein (150 mm), and common iliac vein (200 mm) were used to group limbs as having <50% (low-grade stenosis [LGS]) or ≥50% (high-grade stenosis [HGS]) stenosis. The variables compared included the visual analog scale (VAS) for pain score, venous clinical severity score (VCSS; range, 0-27), ulcer healing, supine foot venous pressures, QOL (20-item chronic venous disease QOL questionnaire), and stent patency. A composite chronic venous insufficiency score (CCVIS) incorporating the VAS score, VCSS, and CIVIQ-20 score for predicting improvement after stenting was evaluated.

RESULTS

Of the 480 limbs, 283 and 197 were in the LGS and HGS groups, respectively. A preponderance of women, left laterality, and post-thrombotic syndrome were noted in both groups. At baseline, although no difference was found in the VAS for pain score between groups, the LGS group had a higher VCSS than did the HGS group (P = .05). The baseline median supine foot venous pressure was 15 and 14 mm Hg in the LGS and HGS groups, respectively (P = .17). At 24 months after stenting, the mean VCSS had improved from 6.3 to 4.4 (P < .0001) and from 5.7 to 3.7 (P < .0001) in the LGS and HGS groups, respectively, without significant differences between the two groups (P = .07). A greater prevalence of ulcers was found in the LGS group (18% vs 11%; P = .04), with no differences in healing (P = .41) or recurrence rates (P = .36). The QOL scores had improved in both groups (LGS, from 58 to 37 [P < .0001]; HGS, from 61 to 35 [P < .0001]), without differences between the two groups (P > .3). No significant differences in stent patency or reinterventions rates were found. A baseline CCVIS of ≥84.5, ≥86.9, or ≥105.3 was needed for a 30-, 40-, and 50-point improvement in most limbs after stenting.

CONCLUSIONS

The degree of IVUS-determined iliofemoral venous stenosis did not appear to affect the initial clinical presentation, CEAP (clinical, etiologic, anatomic, pathophysiologic) clinical class, supine foot venous pressure, clinical improvement, QOL improvement, stent patency, or reintervention rates after stenting. Patients presenting with QOL-impairing symptoms in whom conservative treatment has failed merit consideration of correction of their obstruction even if the degree of stenosis is <50%. The use of a CCVIS might be helpful but requires further study.

Comparative angiotomographic study of swine vascular anatomy: contributions to research and training models in vascular and endovascular surgery

Background

Medium and large animal models allow researchers to evaluate the efficacy and safety of cardiovascular procedures in systems that resemble human anatomy and can be used to simulate scenarios for training purposes. Although porcine models have been used extensively, many physiological and anatomical features remain unknown or only superficially described.

Objectives

To describe the normal porcine vascular anatomy on computed tomography scans, compare it to human vascular anatomy, and discuss the application of porcine models for open and endovascular procedures.

Methods

Three male Landrace pigs underwent computed tomography. The vascular anatomy of the neck, thorax, abdomen, and limbs was analyzed and described; relevant similarities and differences between porcine and human vascular anatomies and the implications for vascular procedures in pigs are highlighted.

Results

The carotid territory, aortic arch, and terminal aorta branches all show marked differences in pigs compared to their human counterparts. Compressions of both left renal and common iliac veins were detected, analogous to those seen in human Nutcracker and May-Thurner syndromes. Vascular measurements (diameters, lengths, and angles) of several different porcine territories are presented.

Conclusions

The data presented should be useful for planning preclinical trials and basic research and for refining surgical training using porcine models in vascular fields.

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.

Role of laser ablation in recalcitrant instent restenosis post iliofemoral venous stenting

Instent restenosis (ISR) represents the most common reason for recurrent symptoms requiring reintervention in patients who have undergone venous stenting for chronic iliofemoral venous obstruction. Treatment of ISR requires stent angioplasty typically using angioplasty balloons equal to or larger than the rated diameter of the stent. At times this does not yield the required result, and in these patients, utilization of a laser catheter supported by an angled sheath is helpful to ablate the ISR or make it more amenable to repeat balloon angioplasty. The authors report their experience with this technique for 18 patients with recurrent symptoms impacting quality of life as a result of recalcitrant ISR in this retrospective review of contemporaneously entered electronic medical record data. 12 (67%) limbs underwent laser ablation only, while 6 (33%) limbs underwent additional angioplasty post laser ablation. Post intervention for ISR, at 12 months, the venous clinical severity score improved from 5 to 3.5 (P = .0005) and the VAS pain score went from 7 to 5 (P = .0005). At 10 months, primary patency was 87% and primary assisted patency was 100%. There were no stent occlusions. Laser ablation of recalcitrant instent restenosis in patients presenting with recurrent chronic iliac venous obstruction post iliofemoral venous stenting is a safe and effective option. Corroboration from larger studies is warranted.

A retrospective comparison of thrombectomy followed by stenting and thrombectomy alone for the management of deep vein thrombosis with May-Thurner syndrome

OBJECTIVE

To summarize the clinical results of thrombectomy with stenting (TBS) in patients with deep venous thrombosis (DVT) secondary to May-Thurner syndrome (MTS) compared with the outcomes in patients treated with thrombectomy alone (TB).

METHODS

A retrospective observation of patients with proximal DVT secondary to MTS was conducted in our institution. Patients accepted treatment including either catheter-directed TBS or TB. The complications and stent patency rates were recorded after treatments. The clinical results were assessed in both groups. The independent predictors for in-stent restenosis were further calculated in this study.

RESULTS

We included 372 patients with DVT secondary to MTS. Two hundred twenty-one patients received treatment with thrombectomy with TBS and 151 with TB. A longer mean procedure time (65.1 ± 13.9 minutes vs 49.5 ± 15.7 minutes; P < .001) and higher venous perforation rate (23 patients vs 5 patients; P = .011) were observed in the TBS group than in the TB group. The median follow-up time was 34 months. The patency rates in the TBS group at 36 months were as follows: primary patency rate of 74.0% and secondary patency rate of 92.1%. Independent predictors for restenosis included visible remaining collateral vessels (hazard ratio [HR], 1.12-3.29; P = .02), residual thrombus (HR, 1.40-4.38; P = .002), and tapered iliac vein (HR, 1.26-4.06; P = .006). Clinical results, including Venous Clinical Severity Scores (TBS, 8.0 ± 3.0; TB, 11.4 ± 3.2), Chronic Venous Insufficiency Questionnaire score (TBS, 76.4 ± 4.0; TB, 83.1 ± 4.6), Villalta scores (TBS, 3.8 ± 1.7; TB, 6.6 ± 3.2), and edema scores (TBS, 0.7 ± 0.7; TB, 1.6 ± 0.6), improved significantly in the TBS group.

CONCLUSIONS

TBS is effective and feasible for patients with proximal DVT secondary to MTS. Furthermore, compared with TB, additional stenting might be effective in improving the venous clinical results at follow-up observations.

Long-term outcomes following use of a composite Wallstent-Z stent approach to iliofemoral venous stenting

OBJECTIVE

An endovascular approach has essentially replaced open surgery in the management of symptomatic chronic obstructive iliofemoral venous disease. In the last several years, such a minimally invasive approach has shifted from use of Wallstents alone to a combination of Wallstent-Z stent (composite stenting) to better deal with the iliocaval confluence. This study evaluates the clinical and stent related outcomes following use of composite stenting.

METHODS

A retrospective review of contemporaneously entered EMR data on 535 patients (545 limbs) with initial iliofemoral stents placed over a 4-year period from 2014 to 2017 for symptomatic chronic iliofemoral venous obstruction was performed. Patients who underwent stenting after intervention for acute deep venous thrombosis were excluded. The impact of stenting on clinical outcomes before and after the intervention were evaluated through use of the visual analog scale pain score (0-10), grade of swelling (0-4), and Venous Clinical Severity Score (0-27). Quality of life was appraised using the Chronic Venous Disease quality of life Questionnaire 20 instrument. Kaplan-Meier analysis was used to assess primary, primary assisted and secondary stent patencies, and paired and unpaired t-tests were used to examine clinical outcomes.

RESULTS

Of the 545 limbs that underwent stenting, 183 were in men and 362 were in women. The median age was 60 years. Laterality was right in 205 limbs and left in 340 limbs. Post-thrombotic syndrome was seen in 441 limbs and nonthrombotic iliac vein lesions/May-Thurner syndrome in 104 limbs. At 24 months, visual analog scale pain score went from 5 to 2 (P < .0001), grade of swelling went from 3 to 1 (P < .0001), and Venous Clinical Severity Score went from 6 to 4 (P < .0001). Ulcers were present in 67 limbs and had healed in 49 limbs (73%) over a median follow-up of 26 months. Global Chronic Venous Disease quality of life Questionnaire scores improved from 60 to 36 (P < .0001) after stenting. Cumulative primary, primary-assisted, and secondary patencies at 60 months were 70%, 99% and 91%, respectively. Thirty limbs (5.5%) required contralateral stenting. There was only one instance (0.2%) of contralateral iliofemoral deep venous thrombosis. One hundred eleven limbs (20%) underwent reintervention, including for in-stent restenosis in 44 limbs, stent compression in 2 limbs, in-stent restenosis and stent compression in 48 limbs, and stent occlusion in 17 limbs.

CONCLUSIONS

In patients undergoing iliofemoral venous stenting for obstructive disease, clinical improvement, quality of life improvement, and stent patencies after use of a composite stent configuration are comparable with those seen after exclusive use of Wallstents. However, the use of a composite stent configuration not only decreases the need for contralateral stenting to relieve chronic obstruction, but also decreases the incidence of contralateral iliofemoral deep venous thrombosis.

Three-dimensional computed tomography venogram enables accurate diagnosis and treatment of patients presenting with symptomatic chronic iliofemoral venous obstruction

OBJECTIVE

The last several years has witnessed an increase in the diagnosis and treatment of chronic iliofemoral venous obstructive lesions. Although intravascular ultrasound (IVUS) examination has become the gold standard in the management of chronic iliofemoral venous obstruction (CIVO), it is an invasive technique. To ascertain the usefulness of noninvasive imaging technology in diagnosing and treating CIVO in symptomatic patients, we compared three-dimensional (3D) reconstructions from computed tomography venogram (CTV) with IVUS examination.

METHODS

Twenty-two continuous patients who underwent IVUS interrogation during intervention for CIVO formed the study cohort. Patients who had stenting performed in the setting of chronic total occlusion of the iliofemoral segment or acute iliofemoral deep venous thrombosis were excluded. All patients underwent CTV as part of their standard preoperative work up. Minimal (smallest) luminal areas of the common iliac vein (CIV), external iliac vein (EIV), common femoral vein (CFV) and the inflow channel (segment caudal to the CFV) were obtained from 3D CTV and IVUS. Centerline length measurements were obtained from 3D CTV to estimate the length of the venous stents necessary; the inflow channel luminal area was used to predict the required stent diameter. Pearson correlation was used to evaluate the association between the luminal areas obtained from the two techniques. Agreement was ascertained by use of Bland-Altman limits of agreement. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 3D CTV in predicting luminal areas was also determined. Predicted stent diameters and lengths were compared against actual stent diameters and lengths used.

RESULTS

Pearson correlation statistic for luminal areas between 3D CTV and IVUS for the CIV was 0.89 (P < .01), for EIV was 0.77 (P < .01), and for CFV was 0.69 (P < .01). The correlation statistic for the inflow channel luminal area was 0.90 (P < .01). The sensitivity of 3D CTV in diagnosing CIVO in the CIV, EIV, and CFV were 100%, 100% and 80%, respectively. The specificity was 67%, 57%, and 86%, respectively, in the CIV, EIV, and CFV segments. The positive predictive value of 3D CTV in determining CIVO in the CIV, EIV, and CFV segments was 89%, 83%, and 92%, and the negative predictive value was 100%, 100%, and 67%, respectively. The overall accuracy was 91%, 86%, and 82% in the CIV, EIV, and CFV segments. Thus, 3D CTV is able to predict stent length within 9.5 mm of the actual stent length used. With respect to stent diameter, 3D CTV was able to predict within 2 mm of the actual stent diameter used 91% (20/22) and within 4 mm of the actual stent diameter used 100% (22/22) of the time.

CONCLUSIONS

From a diagnostic standpoint 3D CTV does well with an overall accuracy ranging from 82% in the CFV to 91% in the CIV in predicting CIVO. It is also able to accurately predict venous stent diameter and lengths required, rendering it a good tool in the diagnosis and treatment of symptomatic CIVO.

Imaging findings of pelvic venous insufficiency in patients with postural orthostatic tachycardia syndrome

OBJECTIVES

Some patients with postural orthostatic tachycardia syndrome (POTS) demonstrate improved dysautonomic symptoms following treatment for pelvic venous insufficiency (PVI). This study assessed the prevalence of significant left common iliac vein (LCIV) compression in POTS patients.

METHODS

Radiologists retrospectively reviewed CT images of pelvic veins for 216 women (191 with POTS and 25 age-comparable controls).Quantitative vascular analysis identified percent-diameter compression of the LCIV by the right common iliac artery. Significant LCIV compression was defined as >50%.

RESULTS

Significant LCIV compression was found in 69% (131/191) of females with POTS versus 40% (10/25) in controls. The hypothesis that venous compression and presence of POTS are independent was rejected (p = .005).

CONCLUSIONS

Significant LCIV compression was noted in a majority of female POTS patients, suggesting that incidence of iliac venous obstruction may be higher than the general population. Patients with POTS and symptoms of PVI may benefit from assessment for venous outflow obstruction.

Impact of Presence of Inferior Vena Cava Filter on Iliocaval Stent Outcomes

BACKGROUND

The impact of presence of an IVC filter in patients undergoing stenting for symptomatic femoroiliocaval obstruction has not been explored in detail. This study attempts to fill this gap by evaluating clinical and stent-related outcomes in such patients. The incidence of deep vein thrombosis (DVT) in this setting is also analyzed.

METHODS

A retrospective review of contemporaneously entered EMR data on initial iliocaval stents placed in patients with an indwelling IVC filter (or placed after stenting) over a 15-year period from 2000 to 2015 was performed. A separate matched cohort that underwent initial stenting during the time frame, but which did not have an IVC filter, was utilized as the control group. Clinical outcomes were evaluated through use of the venous clinical severity score (VCSS) and visual analog scale (VAS) pain scores. Incidence of deep venous thrombosis after stenting was also reviewed in both groups. The Kaplan-Meier analysis was used to assess stent patency after intervention while t-tests were used to examine preintervention and postintervention outcomes within and in-between groups.

RESULTS

A total of 50 limbs (40 patients) underwent placement of a femoroiliocaval stent in the setting of a preexisting (49) or post-stent (1) IVC filter [filter group]. The control group had 156 limbs (155 patients). There was no difference in VCSS, VAS pain score, or grade of swelling at baseline between the 2 groups. Over the median follow-up duration (43 months-filter group; 40 months-control group), VCSS went from 6 to 4 at 12 months (P = 0.0001) in the filter group and from 6 to 4 in the control group (P < 0.0001). VAS pain scores went from 7 to 0 at 12 months (P < 0.0001) in the filter group and from 5 to 0 in the control group (P < 0.0001). There was no significant difference in the VCSS scores or VAS pain score between the 2 groups at 12 months (P > 0.05). Overall, there was a statistically significant increase in the incidence of DVT in the filter group (10%) compared to the control group (3%) [P = 0.03%]. Primary, primary assisted, and secondary patencies in the filter/control groups at 48 months were 64%/65% (P = 0.6), 100%/97% (P = 0.5), and 100%/75% (P = 0.4), respectively. Reintervention from in-stent restenosis was noted in 16% of patients in the filter group compared to 4% in the control group (P = 0.006).

CONCLUSIONS

Patients with an IVC filter in the setting of a femoroiliocaval stent tend to have an increased rate of deep venous thrombosis on the stented side. In addition, an increased rate of reintervention secondary to in-stent restenosis was also noted. In light of this, every attempt should be made to remove the IVC filter as soon as the need for the filter no longer exists.

[Antithrombotic therapy after iliac vein stenting]

Stenting for iliac vein stenosis or compression has become a common therapeutic approach in recent years. The antithrombotic therapy after the stent deployment, however, reaches no consensus. Medications strategies and patients' prognoses differ in non-thrombotic, acute thrombotic and chronic thrombotic these three circumstances. Non-thrombotic patients usually possess satisfactory stent patency whatever antithrombotic therapy is used. Anticoagulant is the basic medication for acute thrombotic patients, benefits from additional antiplatelet drug remains to be clarified. In terms of chronic thrombotic patients, their prognoses are unsatisfactory under all antithrombotic therapies. In this review, we outlined the recent progress of antithrombotic therapy after iliac vein stenting, aiming to provide feasible medication plans for each circumstance.

A case report of May-Thurner syndrome induced by anterior lumbar disc herniation: Novel treatment with radiofrequency thermocoagulation

RATIONALE

Lumbar degeneration-related May-Thurner syndrome (dMTS) is characterized by venous compression induced by degenerated lower lumbar structures. Treatment strategies for May-Thurner syndrome (MTS) include clearing the thrombus and correcting venous compression. Despite having different etiological factors from other MTS types, treatments for dMTS are similar, including endovascular angioplasty and continuous anticoagulation therapies. Thus, a particular treatment was designed herein to focus on compressive lumbar structures instead of intravenous management.

PATIENT CONCERNS

A 59-year-old female patient with dMTS, which was induced by inferior vena cava (IVC) stenosis compressed by L4-5 anterior disc herniation.

DIAGNOSIS

The patient was diagnosed with IVC stenosis and L4-5 lumbar disc herniation based on abdominal computed tomography, ultrasound, and lumbar magnetic resonance imaging findings.

INTERVENTIONS

Radiofrequency thermocoagulation (RF) was applied to the patient to decrease the compression caused by anterior disc herniation.

OUTCOMES

After surgery, the patient's swelling started to improve within 5 hours and completely diminished after 48 hours. Postsurgical abdominal ultrasound showed that her IVC patency increased by 20%. On follow-up, her leg symptoms did not recur at 12 months after surgery.

LESSONS

We provided a novel idea in the treatment of dMTS, in which we shifted the treatment focus from endovascular patency restoration to extravascular decompression. Our case proved that RF was effective in treating dMTS, which is a complementary treatment modality to angioplasty.